[ { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/r9ppf-j2b23", "eprint_status": "archive", "datestamp": "2023-10-27 16:34:16", "lastmod": "2023-10-27 16:34:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Lealia-L", "name": { "family": "Xiong", "given": "Lealia L." }, "orcid": "0000-0001-7636-5936" }, { "id": "Garrett-Michael-A", "name": { "family": "Garrett", "given": "Michael A." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Shapiro-M-G", "name": { "family": "Shapiro", "given": "Mikhail G." }, "orcid": "0000-0002-0291-4215" } ] }, "title": "Living Material with Temperature\u2010Dependent Light Absorption", "ispublished": "pub", "full_text_status": "public", "keywords": "General Physics and Astronomy; General Engineering; Biochemistry, Genetics and Molecular Biology (miscellaneous); General Materials Science; General Chemical Engineering; Medicine (miscellaneous)", "note": "
\u00a9 2023 The Authors. Advanced Science published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
\n\nThe authors thank Hanwei Liu, David Tirrell, Priya Chittur, Seunghyun Sim, and Jolena Jie Zhou for helpful discussions about engineered living materials, as well as Red Lhota, Robert Learsch, and Justin Bois for assistance with instrument design. This research was supported by the Defense Advanced Research Project Agency (HR0011-17-2-0037 to M.G.S. and J.A.K.), the Institute for Collaborative Biotechnologies (W911NF-19-D-0001 to M.G.S.), the Jacobs Institute for Molecular Engineering for Medicine (to J.A.K.), and the Elizabeth W. Gilloon Chair (to J.A.K.). L.L.X. was supported by the NSF Graduate Research Fellowship Program. M.A.G. was supported by the NIH MBRS Research Initiative for Scientific Enhancement Program. M.G.S. was an Investigator at the Howard Hughes Medical Institute. Related research in the Shapiro lab was supported by the David and Lucile Packard Foundation and the Dreyfus Foundation.
\n\nL.L.X. and M.G.S. conceived the study. L.L.X. and M.A.G. planned and performed experiments. L.L.X. analyzed data. J.A.K. provided input on research design and data interpretation. L.L.X. and M.G.S. wrote the manuscript with input from all other authors. M.G.S. and J.A.K. supervised the research.
\n\nThe data that support the findings of this study are available from the corresponding author upon reasonable request.
\n\nThe authors declare no conflict of interest.
", "abstract": "Engineered living materials (ELMs) exhibit desirable characteristics of the living component, including growth and repair, and responsiveness to external stimuli. Escherichia coli (E. coli) are a promising constituent of ELMs because they are very tractable to genetic engineering, produce heterologous proteins readily, and grow exponentially. However, seasonal variation in ambient temperature presents a challenge in deploying ELMs outside of a laboratory environment because E. coli growth rate is impaired both below and above 37 \u00b0C. Here, a genetic circuit is developed that controls the expression of a light\u2010absorptive chromophore in response to changes in temperature. It is demonstrated that at temperatures below 36 \u00b0C, the engineered E. coli increase in pigmentation, causing an increase in sample temperature and growth rate above non\u2010pigmented counterparts in a model planar ELM. On the other hand, at above 36 \u00b0C, they decrease in pigmentation, protecting the growth compared to bacteria with temperature\u2010independent high pigmentation. Integrating the temperature\u2010responsive circuit into an ELM has the potential to improve living material performance by optimizing growth and protein production in the face of seasonal temperature changes.
", "date": "2023-10-26", "date_type": "published", "publication": "Advanced Science", "volume": "10", "number": "30", "publisher": "Wiley", "pagerange": "2301730", "issn": "2198-3844", "official_url": "https://authors.library.caltech.edu/records/r9ppf-j2b23", "funders": { "items": [ { "grant_number": "HR0011-17-2-0037" }, { "grant_number": "W911NF\u201019\u2010D\u20100001" }, {}, { "grant_number": "Graduate Research Fellowship" }, {}, {}, {}, {} ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.1002/advs.202301730", "pmcid": "PMC10602556", "primary_object": { "basename": "Advanced Science - 2023 - Xiong - Living Material with Temperature\u2010Dependent Light Absorption.pdf", "url": "https://authors.library.caltech.edu/records/r9ppf-j2b23/files/Advanced Science - 2023 - Xiong - Living Material with Temperature\u2010Dependent Light Absorption.pdf" }, "related_objects": [ { "basename": "advs6342-sup-0001-suppmat.pdf", "url": "https://authors.library.caltech.edu/records/r9ppf-j2b23/files/advs6342-sup-0001-suppmat.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Xiong, Lealia L.; Garrett, Michael A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/p7hcy-mf449", "eprint_id": 121404, "eprint_status": "archive", "datestamp": "2023-08-22 21:09:15", "lastmod": "2023-10-20 15:27:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Molnar-Kristof", "name": { "family": "Molnar", "given": "Kristof" }, "orcid": "0000-0002-5393-2130" }, { "id": "Sasidharan-Pillai-Aswathy", "name": { "family": "Sasidharan Pillai", "given": "Aswathy" } }, { "id": "Chen-Dongjie", "name": { "family": "Chen", "given": "Dongjie" }, "orcid": "0000-0001-5817-4298" }, { "id": "Kaszas-Gabor", "name": { "family": "Kaszas", "given": "Gabor" } }, { "id": "McKenna-Gregory-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Puskas-Judit-E", "name": { "family": "Puskas", "given": "Judit E." }, "orcid": "0000-0001-5282-5256" } ] }, "title": "Investigation of the structure, filler interaction and degradation of disulfide elastomers made by Reversible Radical Recombination Polymerization (R3P)", "ispublished": "pub", "full_text_status": "public", "keywords": "Organic Chemistry; Polymers and Plastics; General Physics and Astronomy; Materials Chemistry", "note": "\u00a9 2023 Elsevier. \n\nThis work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, United States under Award #DE\u2010SC0018891 and a start-up fund of The Ohio State University, United States #11232011000-11-PUSKAS. The work at TTU and Caltech was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, United States under Awards DE-SC0018657 and DE-SC0018655. The authors also gratefully acknowledge funding from USDA-NIFA to Hatch project number OHO01417. GBM also acknowledges support from the Department of Chemical and Biomolecular Engineering at NC State University, United States. The authors thank Maggie Gottfried for her assistance in the synthesis of pDODTs, and Dr. Miroslawa El Fray (West Pomeranian University of Technology, Szeczin, Poland) for the use of the DSC instrument. \n\nCRediT authorship contribution statement. Kristof Molnar: Methodology, Validation, Investigation, Formal analysis, Writing \u2013 original draft, Writing \u2013 review & editing, Visualization. Aswathy Sasidharan Pillai: Methodology, Validation, Investigation, Formal analysis, Writing \u2013 original draft, Visualization. Dongjie Chen: Formal analysis, Writing \u2013 original draft. Gabor Kaszas: Investigation, Formal analysis, Writing \u2013 original draft, Visualization. Gregory B. McKenna: Writing \u2013 original draft, Writing \u2013 review & editing, Supervision, Funding acquisition. Julia A. Kornfield: Writing \u2013 original draft, Writing \u2013 review & editing, Supervision, Funding acquisition. Judit E. Puskas: Conceptualization, Methodology, Writing \u2013 original draft, Writing \u2013 review & editing, Supervision, Funding acquisition. \n\nData availability. Data will be made available on request. \n\nThe authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Judit E. Puskas reports financial support was provided by US Department of Energy. Gregory B. McKenna reports financial support was provided by US Department of Energy. Julia A. Kornfield reports financial support was provided by US Department of Energy. Kristof Molnar reports financial support was provided by US Department of Energy. Dongjie Chen reports financial support was provided by US Department of Energy.", "abstract": "In this paper we report the synthesis and analysis of cyclic polydisulfides, their redox depolymerization as well as their interaction with carbon black. Cyclic poly(3,6-dioxa-1,8-octanedithiol)s (pDODT) were synthesized by Reversible Radical Recombination Polymerization (R3P). R3P is a scalable \"green\" polymerization process using triethylamine (TEA), H\u2082O\u2082 and air for the polymerization of dithiol monomers. pDODTs were synthesized in 5 and 20 g batches. The effect of peroxide concentration (3, 5, 10, 20, 30 %) was investigated. It was found that the molecular weights increased exponentially with increasing peroxide concentrations. At 30 % peroxide concentration pDODTs with M\u2099 up to 400,000 g/mol and polydispersity of 2 were obtained. 700 and 800 MHz NMR were used for investigating the chemical structure of the polymers. The absence of thiol end group signals in polymers made with > 10 wt % H\u2082O\u2082 and M\u2099 < 100,000 g/mol, including a sample of a fractionated polymer with starting M\u2099 = 600,000 g/mol, verified cyclic structures. Dithiothreitol reduced the polymers to monomer and a small percentage of oligomers. Carbon black was shown to increase the moduli of high molecular weight pDODTs. Swelling tests in chloroform showed that polymers made with 20 and 30 w% peroxide swelled 14 and 10 times of their starting weight without dissolving, indicating chemical interaction between the polymers and carbon black. Further analysis of these interesting elastomers, available at the 20 g scale, is in progress.", "date": "2023-06-13", "date_type": "published", "publication": "European Polymer Journal", "volume": "191", "publisher": "Pergamon Press", "pagerange": "Art. NO. 112033", "id_number": "CaltechAUTHORS:20230515-138536000.17", "issn": "0014-3057", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230515-138536000.17", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE\u2010SC0018891" }, { "agency": "Ohio State University", "grant_number": "11232011000-11-PUSKAS" }, { "agency": "North Carolina State University" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018657" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018655" }, { "agency": "Department of Agriculture", "grant_number": "OHO01417" } ] }, "doi": "10.1016/j.eurpolymj.2023.112033", "resource_type": "article", "pub_year": "2023", "author_list": "Molnar, Kristof; Sasidharan Pillai, Aswathy; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/gsq04-jx080", "eprint_id": 120125, "eprint_status": "archive", "datestamp": "2023-08-20 16:42:17", "lastmod": "2023-10-25 16:53:28", "type": "monograph", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Lealia-L", "name": { "family": "Xiong", "given": "Lealia L." }, "orcid": "0000-0001-7636-5936" }, { "id": "Garrett-Michael-A", "name": { "family": "Garrett", "given": "Michael A." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Shapiro-M-G", "name": { "family": "Shapiro", "given": "Mikhail G." }, "orcid": "0000-0002-0291-4215" } ] }, "title": "Self-regulating living material with temperature-dependent light absorption", "ispublished": "unpub", "full_text_status": "public", "note": "The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. \n\nThe authors thank Hanwei Liu, David Tirrell, Priya Chittur, and Seunghyun Sim for helpful discussions about engineered living materials, as well as Red Lhota, Robert Learsch, and Justin Bois for assistance with instrument design. This research was supported by the Defense Advanced Research Project Agency (HR0011-17-2-0037 to M.G.S. and J.A.K.), the Institute for Collaborative Biotechnologies (W911NF-19- D-0001 to M.G.S.), the Jacobs Institute for Molecular Engineering for Medicine (to J.A.K.), and the Elizabeth W. Gilloon Chair (to J.A.K.). L.L.X. was supported by the NSF Graduate Research Fellowship Program. M.A.G. was supported by the NIH MBRS Research Initiative for Scientific Enhancement Program. M.G.S. is an Investigator of the Howard Hughes Medical Institute. Related research in the Shapiro lab is supported by the David and Lucile Packard Foundation and the Dreyfus Foundation. \n\nAUTHOR CONTRIBUTIONS. L.L.X. and M.G.S. conceived the study. L.L.X. and M.A.G. planned and performed experiments. L.L.X. analyzed data. J. A. K. provided input on research design and data interpretation. L.L.X. and M.G.S. wrote the manuscript with input from all other authors. M.G.S. and J.A.K. supervised the research. \n\nThe authors have declared no competing interest.\n\nSubmitted - 2023.03.11.532239v1.full.pdf
Supplemental Material - media-1.pdf
", "abstract": "Engineered living materials (ELMs) exhibit desirable characteristics of the living component, including growth and repair, and responsiveness to external stimuli. Escherichia coli are a promising constituent of ELMs because they are very tractable to genetic engineering, produce heterologous proteins readily, and grow exponentially. However, seasonal variation in ambient temperature presents a challenge in deploying ELMs outside of a laboratory environment, because E. coli growth rate is impaired both below and above 37\u00b0C. Here, we develop a genetically-encoded mechanism for autonomous temperature homeostasis in ELMs containing E. coli by engineering circuits that control the expression of a light-absorptive chromophore in response to changes in temperature. We demonstrate that below 36\u00b0C, our engineered E. coli increase in pigmentation, causing an increase in sample temperature and growth rate above non-pigmented counterparts in a model planar ELM. On the other hand, above 36\u00b0C, they decrease in pigmentation, protecting their growth compared to bacteria with temperature-independent high pigmentation. Integrating our temperature homeostasis circuit into an ELM has the potential to improve living material performance by optimizing growth and protein production in the face of seasonal temperature changes.", "date": "2023-03-22", "date_type": "published", "id_number": "CaltechAUTHORS:20230316-181929000.6", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230316-181929000.6", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Defense Advanced Research Projects Agency (DARPA)", "grant_number": "HR0011-17-2-0037" }, { "agency": "Army Research Office (ARO)", "grant_number": "W911NF-19-D-0001" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "Elizabeth W. Gilloon Professor of Chemical Engineering" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NIH" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.1101/2023.03.11.532239", "primary_object": { "basename": "2023.03.11.532239v1.full.pdf", "url": "https://authors.library.caltech.edu/records/gsq04-jx080/files/2023.03.11.532239v1.full.pdf" }, "related_objects": [ { "basename": "media-1.pdf", "url": "https://authors.library.caltech.edu/records/gsq04-jx080/files/media-1.pdf" } ], "resource_type": "monograph", "pub_year": "2023", "author_list": "Xiong, Lealia L.; Garrett, Michael A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/as7q4-tm007", "eprint_id": 119885, "eprint_status": "archive", "datestamp": "2023-08-22 19:01:26", "lastmod": "2023-10-25 16:47:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chen-Dongjie", "name": { "family": "Chen", "given": "Dongjie" }, "orcid": "0000-0001-5817-4298" }, { "id": "Moln\u00e1r-Krist\u00f3f", "name": { "family": "Molnar", "given": "Kristof" }, "orcid": "0000-0002-5393-2130" }, { "id": "Kim-Hojin", "name": { "family": "Kim", "given": "Hojin" } }, { "id": "Helfer-Carin-A", "name": { "family": "Helfer", "given": "Carin A." }, "orcid": "0000-0003-4550-4942" }, { "id": "Kaszas-Gabor", "name": { "family": "Kaszas", "given": "Gabor" } }, { "id": "Puskas-Judit-E", "name": { "family": "Puskas", "given": "Judit E." }, "orcid": "0000-0001-5282-5256" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "McKenna-Gregory-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" } ] }, "title": "Linear Viscoelastic Properties of Putative Cyclic Polymers Synthesized by Reversible Radical Recombination Polymerization (R3P)", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2023 American Chemical Society. \n\nThis work was primarily supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Awards # DESC0018657 (DC and GBM), #DESC0018891 (C.A.H., K.M., J.E.P., and G.K.), #DE-SC0018655 (H.K. and J.A.K). The authors at OSU also gratefully acknowledge funding from USDA-NIFA under Hatch project number OHO01417. G.B.M. and D.C. thank the John R. Bradford Endowment at Texas Tech University for partial support, and G.B.M. is thankful to the Department of Chemical and Biomolecular Engineering at North Carolina State University for partial support. \n\nThe authors declare no competing financial interest.", "abstract": "Linear viscoelastic properties in both melt and solution states are reported for a series of poly(3,6-dioxa-1,8-octanedithiol) (polyDODT) made by reversible radical recombination polymerization (R3P) under conditions designed to produce linear (LDODT), cyclic (RDODT), and linear\u2013cyclic mixtures (LRDODT). PolyDODT is amorphous (T_g < \u221250 \u00b0C) and highly flexible (entanglement molecular weight M_(e,lin) \u2248 1850 g/mol for LDODT). PolyDODT's low T_g and low M_(e,lin) enable characterization over a wide dynamic range and a wide range of dimensionless weight-average molecular weight Z_w = M_w/M_(e,lin). Measurements at temperatures from \u221257 to 100 \u00b0C provide up to 18 decades of reduced frequency, which is necessary to characterize RDODT melts with Z_w from 23 to 300. The two highest-molecular-weight polymers in the present RDODT series have such high M_w (406k and 556k g/mol) that mass spectrometry, NMR spectroscopy, and even chemical assays for chain ends are unable to rule out up to 2 mol % of linear contaminant. By studying the samples in solution (using dilution to reduce Z_w), we could compare their dynamics with those of previously established high-purity polystyrene (PS) rings (limited to Z_w \u2264 13.6). RDODT solutions with Z_w < 15 (concentrations <5 wt % for RDODT-406k and 556k) have dynamic moduli G* that accord with LCCC-purified PS rings in terms of the frequency dependence (including the absence of a plateau), the progression of shapes of G* as a function of Z_w, and the linear scaling of their zero-shear viscosity \u03b7\u2080 with M_w. The shape of G* as a function of Z_w for solutions of RDODT-406k and -556k also accords with lower Mw RDODT melts (which have \u22641.3 mol % of linear contaminant). Thus, the measurement of the linear viscoelastic properties of appropriate concentrations of high M_w (>200k g/mol) putative cyclic polymers, in which linear chains evade spectroscopic detection, may provide an alternative means (though not fully proven) of validation of sample purity. When Z_w > 15 (including all seven RDODT melts and eight of their solutions), G* has a rubbery plateau. This suggests that the onset of entanglement-like behavior in rings requires 4\u20135-fold greater Z_w than is required for linear chains. Further, the plateau moduli of RDODT samples are indistinguishable from G\u2070_N of the corresponding LDODT (melt or matched-concentration solutions). In entangled linear polymers, the observation that G\u2070_N is independent of Z_w follows from limitations on lateral fluctuations due to neighboring chains becoming independent of position along a given chain. The present results for RDODT suggest that this holds for sufficiently long endless chains, too. While the RDODTs have the same G\u2070_N as entangled LDODTs, when Z_w > 60, the terminal relaxation, if reached at all, of RDODT extends to orders of magnitude lower frequency than an entangled linear polymer of the same Z_w. Consequently, the viscosity of RDODT with Z_w > 60 increases with Z_w much more strongly than the 3.4 power observed for entangled linear polymers. Finally, these novel polymers, with a disulfide-linked backbone and broad relaxation time distribution, may prove important in relation to biodegradable elastomers and materials with exceptional low-frequency dissipation, extending at least 12 decades below the onset of the rubbery plateau.", "date": "2023-02-14", "date_type": "published", "publication": "Macromolecules", "volume": "56", "number": "3", "publisher": "American Chemical Society", "pagerange": "1013-1032", "id_number": "CaltechAUTHORS:20230307-207211000.46", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230307-207211000.46", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018657" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018891" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018655" }, { "agency": "Department of Agriculture", "grant_number": "OHO01417" }, { "agency": "Texas Tech University" }, { "agency": "North Carolina State University" } ] }, "doi": "10.1021/acs.macromol.2c00892", "resource_type": "article", "pub_year": "2023", "author_list": "Chen, Dongjie; Molnar, Kristof; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/smzr5-fh725", "eprint_id": 116722, "eprint_status": "archive", "datestamp": "2023-08-22 17:27:49", "lastmod": "2023-10-24 21:09:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ylitalo-Andrew-S", "name": { "family": "Ylitalo", "given": "Andrew S." }, "orcid": "0000-0003-4086-3508" }, { "id": "Chao-Huikuan", "name": { "family": "Chao", "given": "Huikuan" }, "orcid": "0000-0001-9930-3586" }, { "id": "Walker-Pierre-J", "name": { "family": "Walker", "given": "Pierre J." }, "orcid": "0000-0001-8628-6561" }, { "id": "Crosthwaite-Jacob", "name": { "family": "Crosthwaite", "given": "Jacob" }, "orcid": "0000-0003-4950-3576" }, { "id": "Fitzgibbons-Thomas-C", "name": { "family": "Fitzgibbons", "given": "Thomas C." }, "orcid": "0000-0002-8330-1102" }, { "id": "Ginzburg-Valeriy-G", "name": { "family": "Ginzburg", "given": "Valeriy G." } }, { "id": "Zhou-Weijun", "name": { "family": "Zhou", "given": "Weijun" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Di-Maio-Ernesto", "name": { "family": "Di Maio", "given": "Ernesto" }, "orcid": "0000-0002-3276-174X" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Competition between CO\u2082-philicity and Mixing Entropy Leads to CO\u2082 Solubility Maximum in Polyether Polyols", "ispublished": "pub", "full_text_status": "public", "keywords": "Industrial and Manufacturing Engineering; General Chemical Engineering; General Chemistry", "note": "\u00a9 2022 The Authors. Published by American Chemical Society\nPermits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). \n\nThe authors express their gratitude to Prof. Richard C. Flagan of Caltech for helpful discussions while planning, performing, and writing up this work and to Dr. Sriteja Mantha of Caltech for help with the group contribution method. The authors would also like to thank Dr. Maria Rosaria Di Caprio for help training A.S.Y. to use G-ADSA at the University of Naples. A.S.Y. acknowledges support by the Dow University Partnership Initiative and the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. \n\nThe authors declare no competing financial interest.\n\nPublished - ie2c02396.pdf
Supplemental Material - ie2c02396_si_001.pdf
", "abstract": "In carbon dioxide-blown polymer foams, the solubility of carbon dioxide (CO\u2082) in the polymer profoundly shapes the structure and, consequently, the physical properties of the foam. One such foam is polyurethane-commonly used for thermal insulation, acoustic insulation, and cushioning which increasingly relies on CO\u2082 to replace environmentally harmful blowing agents. Polyurethane is produced through the reaction of isocyanate and polyol, of which the polyol has the higher capacity for dissolving CO\u2082. While previous studies have suggested the importance of the effect of hydroxyl end groups on CO\u2082 solubility in short polyols (<1000 g/mol), their effect in polyols with higher molecular weight (\u22651000 g/mol) and higher functionality (>2 hydroxyls per chain)-as are commonly used in polyurethane foams-has not been reported. Here, we show that the solubility of CO\u2082 in polyether polyols decreases with molecular weight above 1000 g/mol and decreases with functionality using measurements performed by gravimetry-axisymmetric drop-shape analysis. The nonmonotonic effect of molecular weight on CO\u2082 solubility results from the competition between effects that reduce CO\u2082 solubility (lower mixing entropy) and effects that increase CO\u2082 solubility (lower ratio of hydroxyl end groups to ether backbone groups). To generalize our measurements, we modeled the CO\u2082 solubility using a perturbed chain-statistical associating fluid theory (PC-SAFT) model, which we validated by showing that a density functional theory model based on the PC-SAFT free energy accurately predicted the interfacial tension.", "date": "2022-08-31", "date_type": "published", "publication": "Industrial & Engineering Chemistry Research", "volume": "61", "number": "34", "publisher": "American Chemical Society", "pagerange": "12835-12844", "id_number": "CaltechAUTHORS:20220906-252603000", "issn": "0888-5885", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220906-252603000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" } ] }, "doi": "10.1021/acs.iecr.2c02396", "primary_object": { "basename": "ie2c02396.pdf", "url": "https://authors.library.caltech.edu/records/smzr5-fh725/files/ie2c02396.pdf" }, "related_objects": [ { "basename": "ie2c02396_si_001.pdf", "url": "https://authors.library.caltech.edu/records/smzr5-fh725/files/ie2c02396_si_001.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Ylitalo, Andrew S.; Chao, Huikuan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6jexs-vjx27", "eprint_id": 117468, "eprint_status": "archive", "datestamp": "2023-08-20 08:18:48", "lastmod": "2023-10-24 22:32:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lad-Eleonora-M", "name": { "family": "Lad", "given": "Eleonora M." } }, { "id": "Boyer-David-S", "name": { "family": "Boyer", "given": "David S." }, "orcid": "0000-0001-9219-1614" }, { "id": "Heier-Jeffrey-S", "name": { "family": "Heier", "given": "Jeffrey S." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julie A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kuppermann-Baruch-D", "name": { "family": "Kuppermann", "given": "Baruch D." } }, { "id": "Quiroz-Mercado-Hugo", "name": { "family": "Quiroz-Mercado", "given": "Hugo" }, "orcid": "0000-0003-0063-9552" }, { "id": "Aubel-Janine-M", "name": { "family": "Aubel", "given": "Janine M." } }, { "id": "Karageozian-Lisa-S", "name": { "family": "Karageozian", "given": "Lisa S." } }, { "id": "Karageozian-Hampar-L", "name": { "family": "Karageozian", "given": "Hampar L." } }, { "id": "Sarayba-Melvin-A", "name": { "family": "Sarayba", "given": "Melvin A." } }, { "id": "Karageozian-Vicken-H", "name": { "family": "Karageozian", "given": "Vicken H." } }, { "id": "Kaiser-Peter-K", "name": { "family": "Kaiser", "given": "Peter K." } } ] }, "title": "Color Vision and Microperimetry Changes in Nonexudative Age-Related Macular Degeneration After Risuteganib Treatment: Exploratory Endpoints in a Multicenter Phase 2a Double-Masked, Randomized, Sham-Controlled, Crossover Clinical Trial", "ispublished": "pub", "full_text_status": "public", "note": "David S. Boyer and Julie A. Kornfield report receiving a research grant from Allegro Ophthalmics. Janine M. Aubel, Lisa S. Karageozian, Hampar L. Kara-geozian, Melvin A. Sarayba, and Vicken H. Karageozian are employees of Allegro Ophthalmics. Eleonora M. Lad, David S. Boyer, Jeffrey S. Heier, Baruch D. Kuppermann, and Peter K. Kaiser are consultants of Allegro Ophthalmics. David S. Boyer, Jeffrey S. Heier, Baruch D. Kuppermann, Peter K. Kaiser, Janine M. Aubel, Lisa S. Karageozian, Hampar L. Karageozian, Melvin A. Sarayba, Julie A. Kornfield, Hugo Quiroz-Mercado, and Vicken H. Karageozian own Allegro Ophthalmics.", "abstract": "BACKGROUND AND OBJECTIVE:To explore the association between best-corrected visual acuity (BCVA) improvement and changes in microperimetry (MP) and color vision in patients with nonexudative age-related macular degeneration following administration of two 1.0-mg intravitreal doses of risuteganib.\n\nPATIENTS AND METHODS:In a phase 2a, prospective, double-masked, sham-controlled study, eyes with nonexudative age-related macular degeneration and Early Treatment Diabetic Retinopathy Study BCVA between 20/40 and 20/200 were randomized to intravitreal risuteganib (1.0 mg) or sham injection. The risuteganib group received a second 1.0-mg dose, and patients in the sham group crossed over to receive 1.0 mg of risuteganib at week 16. Exploratory endpoints included changes in color vision and mesopic MP.\n\nRESULTS:Thirty-nine patients (risuteganib, n = 25; sham, n = 14) completed the study. There was a significant (P < .05) correlation between BCVA and the total error score (TES) for both Lanthony and Hue Style. Confusion index was close to the criterion for significance (P = .056) in the risuteganib group. All color vision metrics demonstrated a trend toward improvement in risuteganib responders (BCVA letter gain \u22658 letters) and no change in the nonresponders, with significant differences seen in confusion index between the risuteganib and control group (P = .0493) and between responders and nonresponders (P = .0478). MP showed that risuteganib responders improved in mean sensitivity and change in number of loci \u226411 dB and \u22640 dB, whereas nonresponders worsened.\n\nCONCLUSION:All color vision and MP parameters tested trended toward improvement in risuteganib-treated patients and risuteganib responders. Statistically significant improvement was evident in two metrics: confusion index (in risuteganib-treated patients and responders) and number of loci with decreased sensitivity (in responders). A significant correlation between BCVA and both TES Lanthony and TES Hue Style in risuteganib patients provides concurrent evidence of objective and subjective improvement of retinal function.", "date": "2022-08", "date_type": "published", "publication": "Ophthalmic Surgery, Lasers and Imaging Retina", "volume": "53", "number": "8", "publisher": "SLACK, Inc.", "pagerange": "430-438", "id_number": "CaltechAUTHORS:20221017-14861600.30", "issn": "2325-8160", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221017-14861600.30", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Allegro Ophthalmics" } ] }, "doi": "10.3928/23258160-20220725-02", "resource_type": "article", "pub_year": "2022", "author_list": "Lad, Eleonora M.; Boyer, David S.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0m0cw-8nh28", "eprint_id": 115699, "eprint_status": "archive", "datestamp": "2023-08-22 16:53:44", "lastmod": "2023-11-16 16:24:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Lealia-L", "name": { "family": "Xiong", "given": "Lealia L." }, "orcid": "0000-0001-7636-5936" }, { "id": "Garrett-Michael-A", "name": { "family": "Garrett", "given": "Michael A." } }, { "id": "Buss-Marjorie-T", "name": { "family": "Buss", "given": "Marjorie T." }, "orcid": "0000-0002-4266-9197" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Shapiro-M-G", "name": { "family": "Shapiro", "given": "Mikhail G." }, "orcid": "0000-0002-0291-4215" } ] }, "title": "Tunable Temperature-Sensitive Transcriptional Activation Based on Lambda Repressor", "ispublished": "pub", "full_text_status": "public", "keywords": "thermal control; temperature; transactivation; transcription factors; microbial synthetic biology; Biochemistry, Genetics and Molecular Biology (miscellaneous); Biomedical Engineering; General Medicine", "note": "\u00a9 2022 The Authors. Published by American Chemical Society. Attribution 4.0 International (CC BY 4.0).\n\nPublished online 16 June 2022. Published in issue 15 July 2022. \n\nThe authors thank Mohamad Abedi, Cameron Smith, Di Wu, and Deepak Mishra for helpful discussions. Flow cytometry was performed at the Caltech Flow Cytometry Facility. This research was supported by the Defense Advanced Research Project Agency (HR0011-17-2-0037 to M.G.S. and J.A.K.) and the Institute for Collaborative Biotechnologies (W911NF-19-D-0001 to M.G.S.). L.L.X. and M.T.B. were supported by the NSF Graduate Research Fellowship Program. M.A.G. was supported by the NIH MBRS Research Initiative for Scientific Enhancement Program. M.G.S. is an Investigator of the Howard Hughes Medical Institute. Related research in the Shapiro lab is supported by the David & Lucile Packard Foundation and the Dreyfus Foundation. \n\nAuthor Contributions. L.L.X. and M.G.S. conceived the study. L.L.X., M.A.G., and M.T.B. planned and performed experiments. L.L.X. analyzed data. L.L.X. and M.G.S. wrote the manuscript with input from all other authors. M.G.S. and J.A.K. supervised the research. \n\nThe authors declare no competing financial interest.\n\nPublished - acssynbio.2c00093.pdf
Supplemental Material - sb2c00093_si_001.pdf
", "abstract": "Temperature is a versatile input signal for the control of engineered cellular functions. Sharp induction of gene expression with heat has been established using bacteria- and phage-derived temperature-sensitive transcriptional repressors with tunable switching temperatures. However, few temperature-sensitive transcriptional activators have been reported that enable direct gene induction with cooling. Such activators would expand the application space for temperature control. In this technical note, we show that temperature-dependent versions of the Lambda phage repressor CI can serve as tunable cold-actuated transactivators. Natively, CI serves as both a repressor and activator of transcription. Previously, thermolabile mutants of CI, known as the TcI family, were used to repress the cognate promoters PR and PL. We hypothesized that TcI mutants can also serve as temperature-sensitive activators of transcription at CI's natural PRM promoter, creating cold-inducible operons with a tunable response to temperature. Indeed, we demonstrate temperature-responsive activation by two variants of TcI with set points at 35.5 and 38.5 \u00b0C in E. coli. In addition, we show that TcI can serve as both an activator and a repressor of different genes in the same genetic circuit, leading to opposite thermal responses. Transcriptional activation by TcI expands the toolbox for control of cellular function using globally or locally applied thermal inputs.", "date": "2022-07-15", "date_type": "published", "publication": "ACS Synthetic Biology", "volume": "11", "number": "7", "publisher": "American Chemical Society", "pagerange": "2518-2522", "id_number": "CaltechAUTHORS:20220720-917501000", "issn": "2161-5063", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220720-917501000", "funders": { "items": [ { "agency": "Defense Advanced Research Projects Agency (DARPA)", "grant_number": "HR0011-17-2-0037" }, { "agency": "Army Research Office (ARO)", "grant_number": "W911NF-19-D-0001" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/acssynbio.2c00093", "pmcid": "PMC9295150", "primary_object": { "basename": "acssynbio.2c00093.pdf", "url": "https://authors.library.caltech.edu/records/0m0cw-8nh28/files/acssynbio.2c00093.pdf" }, "related_objects": [ { "basename": "sb2c00093_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0m0cw-8nh28/files/sb2c00093_si_001.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Xiong, Lealia L.; Garrett, Michael A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1ckyy-tqc83", "eprint_id": 114838, "eprint_status": "archive", "datestamp": "2023-08-22 15:45:16", "lastmod": "2023-10-24 15:12:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Magee-Eimear", "name": { "family": "Magee", "given": "Eimear" } }, { "id": "Tang-Fengzai", "name": { "family": "Tang", "given": "Fengzai" } }, { "id": "Ozdemir-Esra", "name": { "family": "Ozdemir", "given": "Esra" } }, { "id": "Walker-Marc", "name": { "family": "Walker", "given": "Marc" } }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "Tiziana" }, "orcid": "0000-0001-8947-0655" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Zak-Alla", "name": { "family": "Zak", "given": "Alla" }, "orcid": "0000-0002-3807-3454" }, { "id": "Tenne-Reshef", "name": { "family": "Tenne", "given": "Reshef" }, "orcid": "0000-0003-4071-0325" }, { "id": "McNally-Tony", "name": { "family": "McNally", "given": "Tony" }, "orcid": "0000-0001-5436-4211" } ] }, "title": "WS\u2082 Nanotubes as a 1D Functional Filler for Melt Mixing with Poly(lactic acid):Implications for Composites Manufacture", "ispublished": "pub", "full_text_status": "public", "keywords": "Biopolymers, Composites, Organic polymers, Plastics, Polymers; General Materials Science", "note": "\u00a9 2022 The Authors. Published by American Chemical Society. Attribution 4.0 International (CC BY 4.0).\n\nReceived: February 1, 2022; Accepted: April 20, 2022;\nPublished: May 3, 2022.\n\nThe authors thank WMG, University of Warwick, the \"Weizmann UK\u2500Making Connections\" program, the Israel Science Foundation (no. 330/16), and the PAZY Israeli Foundation for funding this work. T.D.L. thanks Steven Weigand of the 5ID-D beamline at the APS for support during the synchrotron experiments. \n\nThe authors declare no competing financial interest.\n\nPublished - acsanm.2c00489.pdf
Supplemental Material - an2c00489_si_001.pdf
", "abstract": "Multi-walled WS\u2082 nanotubes (NTs) with lengths ranging from 2 to 65 \u03bcm and widths from 50 to 110 nm were synthesized in a horizontal quartz-made reactor by a process yielding NTs with aspect ratios (ARs) between \u223c40 and >1000. The NTs obtained were thermally stable in air up to 400 \u00b0C but were oxidized within the temperature range 400\u2013550 \u00b0C to produce yellow WO\u2083 particles. Critically, 400 \u00b0C is well above the temperature used to mix additives with the majority of melt-processable polymers. The hydrophilic WS\u2082 NTs were easily dispersed in poly(lactic) acid (PLA) using a twin-screw extruder, but the shear stresses applied during melt mixing resulted in chopping of the NTs such that the AR decreased by >95% and the tensile mechanical properties of the PLA were unchanged. Although the as-extruded unfilled PLA was >99% amorphous, the much-shortened WS\u2082 NTs had a significant effect on the crystallization behavior of PLA, inducing heterogeneous nucleation, increasing the crystallization temperature (T\ua700) by \u223c3 \u00b0C and the crystalline content by 15%, and significantly increasing the rate of PLA crystallization, producing smaller and more densely packed spherulites. The reduction in the AR and the nucleating effect of WS\u2082 NTs for PLA are critical considerations in the preparation, by melt mixing, of composites of rigid 1D NTs and polymers, irrespective of the target application, including bone tissue engineering and bioresorbable vascular scaffolds.", "date": "2022-05-27", "date_type": "published", "publication": "ACS Applied Nano Materials", "volume": "5", "number": "5", "publisher": "American Chemical Society", "pagerange": "6385-6397", "id_number": "CaltechAUTHORS:20220520-388233000", "issn": "2574-0970", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-388233000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "University of Warwick" }, { "agency": "Weizmann UK" }, { "agency": "Israel Science Foundation", "grant_number": "330/16" }, { "agency": "PAZY Foundation" } ] }, "doi": "10.1021/acsanm.2c00489", "primary_object": { "basename": "acsanm.2c00489.pdf", "url": "https://authors.library.caltech.edu/records/1ckyy-tqc83/files/acsanm.2c00489.pdf" }, "related_objects": [ { "basename": "an2c00489_si_001.pdf", "url": "https://authors.library.caltech.edu/records/1ckyy-tqc83/files/an2c00489_si_001.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Magee, Eimear; Tang, Fengzai; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1d2fz-k5485", "eprint_id": 113211, "eprint_status": "archive", "datestamp": "2023-08-22 13:53:37", "lastmod": "2023-10-23 22:59:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Molnar-Kristof", "name": { "family": "Molnar", "given": "Kristof" }, "orcid": "0000-0002-5393-2130" }, { "id": "Kim-Hojin", "name": { "family": "Kim", "given": "Hojin" } }, { "id": "Chen-Dongjie", "name": { "family": "Chen", "given": "Dongjie" } }, { "id": "Helfer-Carin-A", "name": { "family": "Helfer", "given": "Carin A." }, "orcid": "0000-0003-4550-4942" }, { "id": "Kaszas-Gabor", "name": { "family": "Kaszas", "given": "Gabor" } }, { "id": "McKenna-Gregory-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Yuan-Chunhua", "name": { "family": "Yuan", "given": "Chunhua" }, "orcid": "0000-0003-2209-4653" }, { "id": "Puskas-Judit-E", "name": { "family": "Puskas", "given": "Judit E." }, "orcid": "0000-0001-5282-5256" } ] }, "title": "PolyDODT: a macrocyclic elastomer with unusual properties", "ispublished": "pub", "full_text_status": "public", "keywords": "Organic Chemistry; Polymers and Plastics; Biochemistry; Bioengineering", "note": "\u00a9 The Royal Society of Chemistry 2022. \n\nReceived 22nd October 2021, Accepted 23rd December 2021, First published\t04 Jan 2022. \n\nThis work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE\u2013SC0018891 and a start-up fund of The Ohio State University #11232011000-11-PUSKAS. The work at TTU and Caltech was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Awards DE-SC0018657 and DE-SC0018655. \n\nThere are no conflicts to declare.\n\nSupplemental Material - d1py01426a1.pdf
", "abstract": "The effect of reaction conditions on the structure of poly(3,6-dioxa-1,8-octanedithiol) (polyDODT) made by Reversible Radical Recombination Polymerization (R3P) using triethylamine (TEA), H\u2082O\u2082 and air was investigated. 800 MHz (1 and 2D) NMR was used to investigate the polymer structures. Sensitivity analysis provided direct evidence for high purity cyclic polyDODT up to M_n \u223c 100\u2006000 g mol\u207b\u00b9. Comparative analysis by High Resolution Multidetector Size Exclusion Chromatography (SEC) using integrated data showed that the cycles had lower viscosity and were more compact (both for R_g and R_h) than linear samples of similar molecular weight. However, differential data revealed unusual behavior. While lower molecular weight cyclic polymers eluted later and had lower intrinsic viscosity than their linear counterparts at the same molecular weight, at higher molecular weights the polymers showed strange behavior: both the diffusion coefficient measured by Quasielastic Light Scattering (QELS) and Mark\u2013Houwink\u2013Sakurada plots of intrinsic viscosity for linear and cyclic polyDODT were found to converge. R3P, an aqueous based \"green\" method is capable of producing polymers at the 10\u2013100 g scale in the lab, which will allow more detailed studies of this new class of biodegradable elastomers so further experimentation can be performed to elucidate the reasons for the unusual findings.", "date": "2022-02-07", "date_type": "published", "publication": "Polymer Chemistry", "volume": "13", "number": "5", "publisher": "Royal Society of Chemistry", "pagerange": "668-676", "id_number": "CaltechAUTHORS:20220202-908512300", "issn": "1759-9954", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220202-908512300", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018891" }, { "agency": "Ohio State University", "grant_number": "11232011000-11-PUSKAS" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018657" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018655" } ] }, "doi": "10.1039/d1py01426a", "primary_object": { "basename": "d1py01426a1.pdf", "url": "https://authors.library.caltech.edu/records/1d2fz-k5485/files/d1py01426a1.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Molnar, Kristof; Kim, Hojin; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/kr4aw-77227", "eprint_id": 112183, "eprint_status": "archive", "datestamp": "2023-09-22 22:31:02", "lastmod": "2023-10-23 23:23:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ramachandran-Karthik", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Shao-Zixuan", "name": { "family": "Shao", "given": "Zixuan" }, "orcid": "0000-0002-4676-6023" }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "Tiziana" }, "orcid": "0000-0001-8947-0655" }, { "id": "Shen-Bo", "name": { "family": "Shen", "given": "Bo" } }, { "id": "Ruiz-Bello-Edgar-E", "name": { "family": "Ruiz Bello", "given": "Edgar E." } }, { "id": "Tammaro-Loredana", "name": { "family": "Tammaro", "given": "Loredana" } }, { "id": "Villani-Fulvia", "name": { "family": "Villani", "given": "Fulvia" }, "orcid": "0000-0001-7301-9819" }, { "id": "Loffredo-Fausta", "name": { "family": "Loffredo", "given": "Fausta" } }, { "id": "Borriello-Carmela", "name": { "family": "Borriello", "given": "Carmela" }, "orcid": "0000-0001-8412-530X" }, { "id": "Di-Benedetto-Francesca", "name": { "family": "Di Benedetto", "given": "Francesca" } }, { "id": "Magee-Eimear", "name": { "family": "Magee", "given": "Eimear" } }, { "id": "McNally-Tony", "name": { "family": "McNally", "given": "Tony" }, "orcid": "0000-0001-5436-4211" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Tungsten disulfide nanotubes enhance flow-induced crystallization and radio-opacity of polylactide without adversely affecting in vitro toxicity", "ispublished": "pub", "full_text_status": "public", "keywords": "Polylactide (PLA); Tungsten disulfide (WS2) nanotubes; Flow-induced crystallization; Biocompatible nanocomposites; Coronary Heart Disease; Bioresorbable Vascular Scaffolds (BVS); Molecular Biology; Biomedical Engineering; Biochemistry; Biomaterials; General Medicine; Biotechnology", "note": "\u00a9 2021 Acta Materialia Inc. Published by Elsevier. \n\nReceived 26 July 2021, Revised 17 October 2021, Accepted 4 November 2021, Available online 17 November 2021. \n\nThis research used resources of the Advanced Photon Source (APS), a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357. We are grateful to the staff of APS beamline 5-D-D, Steven Weigand and James Rix in particular, for their invaluable assistance in acquiring synchrotron X-ray scattering data. We are also indebted to Dan Zhou, a graduate student in the Kornfield group, Dr. Jeremy Wei, a former research scientist in the Kornfield group, and Mark Ladinsky, a scientist at the Caltech electron microscopy core, for their help in microtoming PLA/PLA-WSNT sections and acquiring GPC data and TEM images respectively. This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sk\u0142odowska-Curie grant agreement No 691238, the Jacobs Institute for Molecular Engineering for Medicine at Caltech, the Rosen Center for Bioengineering at Caltech, a National Institutes of Health (NIH) training grant (T32GM112592) and the National Heart, Lung, and Blood Institute of the NIH under Award Number F31HL137308. \n\nThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\n\nAccepted Version - nihms-1757868.pdf
Supplemental Material - 1-s2.0-S1742706121007467-mmc1.docx
Supplemental Material - 1-s2.0-S1742706121007467-mmc2.zip
Supplemental Material - 1-s2.0-S1742706121007467-mmc3.zip
", "abstract": "Treatment of vascular disease, from peripheral ischemia to coronary heart disease (CHD), is poised for transformation with the introduction of transient implants designed to \"scaffold\" regeneration of blood vessels and ultimately leave nothing behind. Improved materials could expand the use of these devices. Here, we examine one of the leading polymers for bioresorbable scaffolds (BRS), polylactide (PLA), as the matrix of nanocomposites with tungsten disulfide (WS\u2082) nanotubes (WSNT), which may provide mechanical reinforcement and enhance radio-opacity. We evaluate in vitro cytotoxicity using vascular cells, flow-induced crystallization and radio-opacity of PLA-WSNT nanocomposites at low WSNT concentration. A small amount of WSNT (0.1 wt%) can effectively promote oriented crystallization of PLA without compromising molecular weight. And radio-opacity improves significantly: as little as 0.5 to 1 wt% WSNT doubles the radio-opacity of PLA-WSNT relative to PLA at 17 keV. The results suggest that a single component, WSNT, has the potential to increase the strength of BRS to enable thinner devices and increase radio-opacity to improve intraoperative visualization. The in vitro toxicity results indicate that PLA-WSNT nanocomposites are worthy of investigation in vivo. Although substantial further preclinical studies are needed, PLA-WSNT nanocomposites may provide a complement of material properties that may improve BVS and expand the range of lesions that can be treated using transient implants.", "date": "2022-01-15", "date_type": "published", "publication": "Acta Biomaterialia", "volume": "138", "publisher": "Elsevier", "pagerange": "313-326", "id_number": "CaltechAUTHORS:20211202-230941847", "issn": "1742-7061", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211202-230941847", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-06CH11357" }, { "agency": "Marie Curie Fellowship", "grant_number": "691238" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "Donna and Benjamin M. Rosen Bioengineering Center" }, { "agency": "NIH Predoctoral Fellowship", "grant_number": "T32GM112592" }, { "agency": "NIH Postdocotral Fellowship", "grant_number": "F31HL137308" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" }, { "id": "Rosen-Bioengineering-Center" } ] }, "doi": "10.1016/j.actbio.2021.11.005", "pmcid": "PMC9505057", "primary_object": { "basename": "1-s2.0-S1742706121007467-mmc2.zip", "url": "https://authors.library.caltech.edu/records/kr4aw-77227/files/1-s2.0-S1742706121007467-mmc2.zip" }, "related_objects": [ { "basename": "1-s2.0-S1742706121007467-mmc3.zip", "url": "https://authors.library.caltech.edu/records/kr4aw-77227/files/1-s2.0-S1742706121007467-mmc3.zip" }, { "basename": "nihms-1757868.pdf", "url": "https://authors.library.caltech.edu/records/kr4aw-77227/files/nihms-1757868.pdf" }, { "basename": "1-s2.0-S1742706121007467-mmc1.docx", "url": "https://authors.library.caltech.edu/records/kr4aw-77227/files/1-s2.0-S1742706121007467-mmc1.docx" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Ramachandran, Karthik; Shao, Zixuan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ra47v-w1r44", "eprint_id": 114452, "eprint_status": "archive", "datestamp": "2023-08-22 10:46:02", "lastmod": "2023-10-24 14:58:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Rocher-Lison", "name": { "family": "Rocher", "given": "L." }, "orcid": "0000-0002-6383-565X" }, { "id": "Lennon-Alex-B", "name": { "family": "Lennon", "given": "A. B." }, "orcid": "0000-0003-2722-8227" }, { "id": "Ylitalo-Andrew-S", "name": { "family": "Ylitalo", "given": "A. S." }, "orcid": "0000-0003-4086-3508" }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "T." }, "orcid": "0000-0001-8947-0655" }, { "id": "Menary-Gary-H", "name": { "family": "Menary", "given": "G. H." }, "orcid": "0000-0003-2771-7258" }, { "id": "Miscioscia-Riccardo", "name": { "family": "Miscioscia", "given": "R." }, "orcid": "0000-0001-6586-4182" }, { "id": "De-Filippo-Giovanni", "name": { "family": "De Filippo", "given": "G." } }, { "id": "Pandolfi-Giuseppe", "name": { "family": "Pandolfi", "given": "G." }, "orcid": "0000-0002-3784-8326" }, { "id": "Villani-Fulvia", "name": { "family": "Villani", "given": "F." }, "orcid": "0000-0001-7301-9819" } ] }, "title": "Metastable structures, interplay of sequential deformations, and interactions between tungsten disulfide nanotubes and poly(L-lactide) studied by in situ X-ray scattering", "ispublished": "pub", "full_text_status": "public", "keywords": "stretch-blow molding; WS2NT; flow-induced crystallization; microdiffraction; SAXS/WAXS", "note": "\u00a9 2021 International Union of Crystallography.\n\nPublished - a60156.pdf
", "abstract": "Polymer crystallization, particularly near the glass transition, exhibits strong nonlinearities and prolonged metastability that enable fabrication of devices with complex hierarchal structure from nm to mm. A fascinating example arises in the production of bioresorbable\nscaffolds (BRS) from poly(L-lactide) (PLLA), in which a sequence of processes (extrusion, stretch-blow molding and crimping) create diverse semicrystalline morphologies, side-by-side within a span of a hundred microns (Figure 1). To discover how these structures form, we need to examine transient structure under conditions that mimic manufacturing processes. An apparatus that enables scattering measurements during the stretch-blow molding step, called \"tube expansion\" imposes a nearly constant-width elongation as it converts an extruded \"preform\" into an \"expanded tube\". To increase the range of accessible properties of PLLA-based BRS, we use this\napparatus to examine inorganic nanotubes as potential reinforcing agents that also enhance radiopacity, relevant to clinical applications. Understanding how their microstructure develops during processing is relevant to increasing strength to enable thinner devices and improving radiopacity to enable imaging during implantation. Consistent with the premise of this MS, in-situ X-ray scattering reveals unanticipated phenomena in the transient microstructure of PLLA/WS2NTs nanocomposites during \"tube expansion\" (Figure 2).", "date": "2021-08", "date_type": "published", "publication": "Acta Crystallographica Section A", "volume": "A77", "number": "S1", "publisher": "International Union of Crystallography", "pagerange": "Art. No. C575", "id_number": "CaltechAUTHORS:20220425-171236077", "issn": "2053-2733", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220425-171236077", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1107/S0108767321091194", "primary_object": { "basename": "a60156.pdf", "url": "https://authors.library.caltech.edu/records/ra47v-w1r44/files/a60156.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Kornfield, J. A.; Rocher, L.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/a038v-nnp59", "eprint_id": 112461, "eprint_status": "archive", "datestamp": "2023-08-20 04:33:30", "lastmod": "2023-10-23 22:33:30", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia Ann" }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Polymers and nanocomposites to treat vascular disease without a trace", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2021 American Chemical Society.", "abstract": "A wave of bioresorbable devices are being introduced to treat vascular disease in the heart and limbs. Biodegradable semicryst. polymers provide the structural material of leading bioresorbable scaffolds (BRSs), a credit to innovative processing methods developed to achieve new combinations of strength, toughness and hydrolysis profiles. With Abbott Vascular, we discovered the key to resilient poly L-lactide (PLLA) lies in the interaction of two manufg. steps-tube expansion and crimping. X-ray microdiffraction revealed dramatic gradients of structure created during crimping slow hydrolysis precisely where stress is concd., preserving strength where it is needed most. Even after 9 mo of hydrolysis in vitro, despite a 40% decrease in PLLA mol. wt., the BRS retains its initial strength. Clin. complications motivate thinner devices that are visible in x-ray radiog. during and after implantation. Toward the goal of stronger, radiopaque, bioresorbable materials, we explore PLLA reinforcement by inorg. nanotubes (NT) with strong x-ray absorption, specifically, tungsten disulfide (WS2). The effects of WS2NT on PLLA crystn. reveal a new interaction between early processing steps in BRS manuf. (preform extrusion and tube expansion). Innovative processing methods developed by biomedical device manufacturers give PLLA resilience to survive crimping, deployment and months of hydrolysis, fueling optimism that scaffolds will support arteries' ability to heal, ultimately enabling recovery from vascular diseases without leaving a trace.", "date": "2021-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20211215-162926638", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211215-162926638", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2021", "author_list": "Kornfield, Julia Ann" }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/tjy1r-6b253", "eprint_id": 112493, "eprint_status": "archive", "datestamp": "2023-08-20 04:34:42", "lastmod": "2023-10-23 22:34:40", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Lealia", "name": { "family": "Xiong", "given": "Lealia" } }, { "id": "Garrett-Michael-A", "name": { "family": "Garrett", "given": "Michael A." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia Ann" }, "orcid": "0000-0001-6746-8634" }, { "id": "Shapiro-M-G", "name": { "family": "Shapiro", "given": "Mikhail G." }, "orcid": "0000-0002-0291-4215" } ] }, "title": "Toward a thermally self-regulating living material", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2021 American Chemical Society.", "abstract": "Engineered living materials (ELMs) retain desirable characteristics of the living component, such as exponential growth, self-repair, and responsiveness to external stimuli. Escherichia coli are a promising constituent of ELMs because they are very tractable to genetic engineering.Variation in ambient temp. presents a challenge in deploying ELMs outside of a lab. environment. E. coli experience maximal growth near 37\u00b0C. In addn., E. coli protein synthesis decreases below 37\u00b0C, while protein misfolding and aggregation tends to increase with temp.Here, we develop a genetically encoded\nmechanism for autonomous temp. homeostasis in ELMs contg. E. coli by engineering circuits that change expression of a light-absorptive chromophore in response to changes in temp. Our simulations show that by increasing absorptivity below 36\u00b0C, the material will heat above the ambient temp. to preserve optimal growth and protein expression, and thus material functionality.We program bacteria to respond to temp. using temp.-sensitive transcriptional repressors (TSRs). \n\nTwo families of TSRs with switching temps. ranging from 36\u00b0C to 44\u00b0C have been developed in our lab by directed evolution of TcI, a temp.-sensitive mutant of bacteriophage l repressor cI, and TlpA, a transcriptional auto-repressor from the virulence plasmid of Salmonella typhimurium. These thermal bioswitches can be further tuned for optimal switching in the ELM application. Formation of a black chromophore from a pale yellow precursor is enzymically catalyzed. Integrating the gene for this enzyme into a genetic circuit with a down-shifted mutant of TlpA enables E. coli to express black chromophore at low temps. and not at high temps.We measure the ability of patches of E. coli (simulating an E. coli-based ELM) to grow in a custom lighted incubator at different ambient temps. by observing patch diam. and thickness. We continuously monitor E. coli temp. under illumination using thermal IR imaging with custom controller software. Comparison of exptl. results and simulations will be presented. We demonstrate thermal control of pigmentation and resulting increase in sample temp.", "date": "2021-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20211216-234818185", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211216-234818185", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2021", "author_list": "Xiong, Lealia; Garrett, Michael A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/df124-y1h41", "eprint_id": 110376, "eprint_status": "archive", "datestamp": "2023-08-20 03:33:23", "lastmod": "2023-10-23 19:37:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Boyer-David-S", "name": { "family": "Boyer", "given": "David S." }, "orcid": "0000-0001-9219-1614" }, { "id": "Gonzalez-Victor-H", "name": { "family": "Gonzalez", "given": "Victor H." } }, { "id": "Kunimoto-Derek-Y", "name": { "family": "Kunimoto", "given": "Derek Y." } }, { "id": "Maturi-Raj-K", "name": { "family": "Maturi", "given": "Raj K." }, "orcid": "0000-0002-8894-1846" }, { "id": "Roe-Richard-H", "name": { "family": "Roe", "given": "Richard H." } }, { "id": "Singer-Michael-A", "name": { "family": "Singer", "given": "Michael A." } }, { "id": "Xavier-Samantha", "name": { "family": "Xavier", "given": "Samantha" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julie A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kuppermann-Baruch-D", "name": { "family": "Kuppermann", "given": "Baruch D." } }, { "id": "Quiroz-Mercado-Hugo", "name": { "family": "Quiroz-Mercado", "given": "Hugo" }, "orcid": "0000-0003-0063-9552" }, { "id": "Aubel-Janine", "name": { "family": "Aubel", "given": "Janine" }, "orcid": "0000-0003-3428-311X" }, { "id": "Karageozian-Hampar-L", "name": { "family": "Karageozian", "given": "Hampar L." } }, { "id": "Park-John-Y", "name": { "family": "Park", "given": "John Y." } }, { "id": "Karageozian-Vicken-H", "name": { "family": "Karageozian", "given": "Vicken H." } }, { "id": "Karageozian-Lisa", "name": { "family": "Karageozian", "given": "Lisa" } }, { "id": "Sarayba-Melvin-A", "name": { "family": "Sarayba", "given": "Melvin A." } }, { "id": "Kaiser-Peter-K", "name": { "family": "Kaiser", "given": "Peter K." } } ] }, "title": "Safety and Efficacy of Intravitreal Risuteganib for Non-Exudative AMD: A Multicenter, Phase 2a, Randomized, Clinical Trial", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2021 Boyer, Gonzalez, Kunimoto et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International ( https://creativecommons.org/licenses/by-nc/4.0). This license allows users to copy and distribute, to remix, transform, and build upon the article non-commercially, provided the author is attributed and the new work is non-commercial. \n\nOriginally submitted December 17, 2020. Revision received February 18, 2021. Accepted for publication March 23, 2021. \n\nDr. Boyer reports grants and personal fees from Allergan, Aerpio, Allegro, Allergan, Boehringer Ingelheim, Clearside, Ionis, Genentech, Graybug, Novartis, Iveric, Regeneron, and Stealth; personal fees from Alcon, Acucela, Bausch + Lomb, BioMotiv, Glaukos, Kala, and Thea; and grants from Bayer and Santen outside the submitted work. Dr. Gonzalez is a consultant for and has received research support from Genentech, Regeneron, Oxurion (a Thrombogenics Inc. subsidiary), Alcon/Novartis, Allergan, Valeant, Santen Pharmaceutical, and Astellas Institute for Regenerative Medicine; is a consultant for, has received research support from, and has personal financial interests in Alimera; is a consultant for Bausch + Lomb, Topcon, Beaver-Visitec International Inc., and Abbvie; has personal financial interest in Panoptica; and has received financial support from Iconic Therapeutics, Allegro Ophthalmics, DRCRNet, Boehringer Ingelheim, Insite Vision Inc., Graybug Vision, Inc., Chengdu Kanghong Biotechnology Co, Ltd, Mallinckrodt ARD Inc., Opthea Ltd., 60\u00b0 Pharmaceuticals, Apellis Pharmaceuticals, and Ribomic USA Inc. outside the submitted work. Dr. Kunimoto is a consultant for and has received research grants from Allegro, Allergan, and Genentech; is a consultant for Bausch + Lomb, D.O.R.C., Novartis, and Regeneron; and has received research grants from Roche outside the submitted work. Dr. Maturi has received research grants from Aerpio, Allegro, Allergan, Boehringer Ingelheim, Genentech, Graybug, Inc., Gyroscope, Kalvista, Samsung Bioepis, Santen, and Oxurion outside the submitted work. Dr. Singer is a consultant for and has received research grants from Aerie, Allegro, Kodiak, and Santen; is a consultant/speaker for and has received research grants from Allergan, Genentech, Novartis, and Regeneron; is a consultant for Eyepoint; is a speaker for Mallinckrodt and Spark; and has received research funding from DRCRNet, Icon, Ionis, Kalvista, Ophthea, Optos, Senju, and Sydnexis outside the submitted work. Dr. Xavier has received grants from Allegro Ophthalmics, LLC outside the submitted work. Dr. Kornfield received grants and non-financial support from Allegro Ophthalmics, LLC, during the conduct of this study, as well as profits interest units (PIU) in Allegro Ophthalmics outside the submited work. Dr. Kupperman has received clinical research funding from Alcon, Apellis, Clearside, GSK, and Ionis; is a consultant for and has received clinical research funding from Allergan, Genentech, IVERIC Bio, jCYTE, Novartis, and Regeneron; and is a consultant for Allegro, Aprea, Cell Care, Dose, Eyedaptic, Galimedix, Glaucos, Interface Biologics, Oculis, Revana, Ripple Therapeutics, and Theravance Biopharma outside the submitted work. Dr. Quiroz-Mercado has stock in Allegro Ophthalmics, LLC. Ms. Aubel, Dr. H Karageozian, Dr. Park, Dr. V Karageozian, Ms. Karageozian, Dr. Sarayba, and Dr. Kaiser are employees of and have stock in Allegro Ophthalmics, LLC. Dr. Roe reports no relevant financial disclosures.\n\nPublished - 23258160-20210528-05.pdf
", "abstract": "Background and Objective: To evaluate the safety and efficacy of 1.0 mg risuteganib in subjects with nonexudative age-related macular degeneration (AMD). \n\nPatients and Methods: This was a phase 2a, prospective, double-masked, sham-controlled study. Eyes with nonexudative (dry) AMD and Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA) between 20/40 and 20/200 were included. Subjects were randomized to intravitreal 1.0 mg risuteganib or sham injection. At Week 16, subjects in the risuteganib group received a second 1.0-mg dose and the sham group crossed over to receive a dose of 1.0 mg risuteganib and were evaluated at Week 28. The primary endpoint was proportion of subjects with 8 letters ETDRS or more BCVA gain from baseline to Week 28 in the risuteganib group versus baseline to Week 12 for the sham group. BCVA was tested and subjects were observed for adverse events (AEs) every 4 weeks until completion of the study at 32 weeks. \n\nResults: Forty-five subjects (risuteganib, n = 29; sham, n = 16) were enrolled in the study, of whom 39 (risuteganib, n = 25; sham, n = 14) completed the study and were included in the per protocol efficacy analysis. At baseline, mean age was 78.8 and 75.9 years and mean BCVA was 67.1 and 64.4 letters in the sham and risuteganib groups, respectively. The primary endpoint was met by 48% of the risuteganib group at Week 28 and 7% of the sham group at Week 12 (P = .013). Of the risuteganib subjects, 20% gained 15 letters or more at Week 28, whereas no patients in the sham group at Week 12 achieved this visual acuity gain. The only ocular treatment-related treatment-emergent AE was vitreous floaters, which spontaneously recovered without sequelae. No drug-related serious AE was reported. \n\nConclusions: Risuteganib demonstrated significant BCVA improvement in patients with non-exudative AMD. No drug-related AEs were seen during a 32-week observation period.", "date": "2021-06", "date_type": "published", "publication": "Ophthalmic Surgery, Lasers and Imaging Retina", "volume": "52", "number": "6", "publisher": "SLACK, Inc.", "pagerange": "327-335", "id_number": "CaltechAUTHORS:20210823-142252660", "issn": "2325-8160", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210823-142252660", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.3928/23258160-20210528-05", "primary_object": { "basename": "23258160-20210528-05.pdf", "url": "https://authors.library.caltech.edu/records/df124-y1h41/files/23258160-20210528-05.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Boyer, David S.; Gonzalez, Victor H.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1yg85-0pf76", "eprint_id": 111628, "eprint_status": "archive", "datestamp": "2023-08-20 03:33:44", "lastmod": "2023-10-23 20:39:51", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shao-Zixuan", "name": { "family": "Shao", "given": "Zixuan" }, "orcid": "0000-0002-4676-6023" }, { "id": "Hackett-Sean-F", "name": { "family": "Hackett", "given": "Sean F." }, "orcid": "0000-0002-9553-4341" }, { "id": "Formica-Raquel", "name": { "family": "Formica", "given": "Raquel" } }, { "id": "Kanan-Yogita", "name": { "family": "Kanan", "given": "Yogita" } }, { "id": "Zhou-Dan", "name": { "family": "Zhou", "given": "Dan" } }, { "id": "Park-John-Y", "name": { "family": "Park", "given": "John Y." } }, { "id": "Karageozian-Hampar-L", "name": { "family": "Karageozian", "given": "Hampar L." } }, { "id": "Karageozian-Vicken-H", "name": { "family": "Karageozian", "given": "Vicken H." } }, { "id": "Campochiaro-Peter-A", "name": { "family": "Campochiaro", "given": "Peter A." }, "orcid": "0000-0003-2531-8229" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Suppression of Murine Choroidal and Retinal Neovascularization by Risuteganib and the Accompanying Transcriptome Changes in the OIR Retina", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2021 Association for Research in Vision and Ophthalmology.\nThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.\n\nPublished - Shao_2021p186.pdf
", "abstract": "Purpose : Wet age-related macular degeneration and diabetic retinopathy are leading causes of blindness with characteristic neovascularization (NV) of the choroid (CNV) or retina (RNV), respectively. This preclinical study explores effects of the investigational drug, risuteganib (RSG), in cell culture and three murine disease models using histology and transcriptomics.\n\nMethods : In photocoagulation-induced CNV model, 1-50\u00b5g RSG or control peptides were intraocularly injected, followed by measurement of NV area on day 14 (n=4). The rho/VEGF model of subretinal NV was used to examine: i) injection of vehicle, 25\u00b5g RSG, 10\u03bcg ranibizumab, or combination of two drugs, followed by NV area measurement on day 7 (n=5), and ii) vascular leakage 1 day after PBS or 25\u00b5g RSG injection (n=8). In oxygen-induced retinopathy (OIR) RNV model, 0.1-50\u00b5g of RSG or PBS were injected and NV area was measured on day 5 (n=8). Student's t-test was used except with ANOVA in the rho/VEGF study of NV. Transcriptome changes associated with RNV and 10\u00b5g RSG injection was measured by RNA-seq. Changes in gene levels were determined by edgeR and enrichment of biological processes/pathways by goseq. RT-CES-based HREC cell adhesion and migration assays were used to test effect of 43-1393\u00b5M RSG on surfaces coated with vitronectin (VN) or fibronectin (FN) (n=2), statistical test by ANOVA.\n\nResults : In the photocoagulation model, 10 and 25\u00b5g RSG reduced the area of CNV (p=0.0453, 0.0498). In the rho/VEGF model, RSG (p<0.001) and ranibizumab (p<0.001) both reduced NV area, while combination showed further reduction (p<0.05); RSG reduced vascular leakage by 24% (p=0.017). In OIR, 12.5, 25, and 50\u00b5g RSG (p=0.0271, 0.0414, 0.0403) reduced NV area. Transcriptome data showed biological processes and pathways related to angiogenesis, inflammation, integrin, cell adhesion and migration were enriched in genes elevated in OIR retina and reduced with RSG. Cell migration on FN was inhibited at low RSG dose (p<0.01), while migration on VN (p<0.01), adhesion on VN (p<0.05) and FN (p<0.01) were inhibited at high RSG dose.\n\nConclusions : RSG demonstrated anti-NV property, reduced retinal vascular leakage, and inhibited cell adhesion and migration. Transcriptome data suggest important pathological cellular responses are modulated by RSG, with possible therapeutic implication for treatment of human retinal diseases.", "date": "2021-06", "date_type": "published", "publication": "Investigative Ophthalmology & Visual Science", "volume": "62", "number": "8", "publisher": "Association for Research in Vision and Ophthalmology", "pagerange": "Art. No. 186", "id_number": "CaltechAUTHORS:20211025-153919809", "issn": "0146-0404", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211025-153919809", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "primary_object": { "basename": "Shao_2021p186.pdf", "url": "https://authors.library.caltech.edu/records/1yg85-0pf76/files/Shao_2021p186.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Shao, Zixuan; Hackett, Sean F.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/5hmwc-xne42", "eprint_id": 109375, "eprint_status": "archive", "datestamp": "2023-08-22 09:56:51", "lastmod": "2023-10-23 17:53:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rocher-Lison", "name": { "family": "Rocher", "given": "Lison" } }, { "id": "Ylitalo-Andrew-S", "name": { "family": "Ylitalo", "given": "Andrew S." }, "orcid": "0000-0003-4086-3508" }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "Tiziana" } }, { "id": "Miscioscia-Riccardo", "name": { "family": "Miscioscia", "given": "Riccardo" }, "orcid": "0000-0001-6586-4182" }, { "id": "De-Filippo-Giovanni", "name": { "family": "De Filippo", "given": "Giovanni" } }, { "id": "Pandolfi-Giuseppe", "name": { "family": "Pandolfi", "given": "Giuseppe" } }, { "id": "Villani-Fulvia", "name": { "family": "Villani", "given": "Fulvia" } }, { "id": "Zak-Alla", "name": { "family": "Zak", "given": "Alla" } }, { "id": "Menary-Gary-H", "name": { "family": "Menary", "given": "Gary H." }, "orcid": "0000-0003-2771-7258" }, { "id": "Lennon-Alex-B", "name": { "family": "Lennon", "given": "Alex B." }, "orcid": "0000-0003-2722-8227" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Interaction of Poly L-Lactide and Tungsten Disulfide Nanotubes Studied by in Situ X-ray Scattering during Expansion of PLLA/WS\u2082NT Nanocomposite Tubes", "ispublished": "pub", "full_text_status": "public", "keywords": "polylactide; tungsten disulfide nanotubes; nanocomposites; blow molding; WAXS; SAXS; bioresorbable vascular scaffold", "note": "\u00a9 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). \n\nReceived: 21 April 2021; Revised: 19 May 2021; Accepted: 24 May 2021; Published: 27 May 2021. \n\nL.R. would like to thank Graham Garrett for his help and advice during tube extrusion, Boston Scientific Ltd. (Marlborough, MA, USA) for their support and collaboration, and Corbion Biomaterials, The Netherlands, for the kind gift of PLLA. The authors acknowledge Karthik Ramachandran for providing the initial Matlab code to analyze the scattering data, Orland Bateman, Karl Joyce, Brian Dillon, and John Dale for their help and expertise with the microcopy analysis, and also Jordan Barr and Judith Cameron for performing the offline experiments in water bath. The authors would also like to thank all the staff at beamline 5-ID-D DND-CAT of the Advanced Photon Source (APS) at the Argonne National Laboratories, especially Steven Weigand, for their invaluable support for the success of the experiments. \n\nThis project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sk\u0142odowska-Curie grant agreements No 813869 and No 691238. This publication article reflects only the author's view, and the REA is not responsible for any use that may be made of the information it contains. A.Y. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. A. Z. acknowledges Israel Science Foundation (ISF 330-16) for supporting synthesis of WS\u2082 nanotubes.\n\nAuthor Contributions: A.Z. synthesized the WS\u2082 nanotubes and analyzed them by SEM and TEM; G.H.M., A.B.L., T.D.L. and J.A.K. designed research; L.R. manufactured the preforms; R.M., G.D.F., and G.P. constructed the apparatus; L.R., A.S.Y., F.V., R.M., G.D.F., G.P. and T.D.L. performed experiments; L.R., A.S.Y., T.D.L. and J.A.K. analyzed data; L.R., R.M., A.S.Y., A.Z., G.H.M., A.B.L., T.D.L. and J.A.K. wrote the paper. All authors have read and agreed to the published version of the manuscript. \n\nInstitutional Review Board Statement: Not applicable. \n\nInformed Consent Statement: Not applicable. \n\nData Availability Statement: Not applicable. \n\nThe authors declare no conflict of interest.\n\nPublished - polymers-13-01764.pdf
", "abstract": "In situ synchrotron X-ray scattering was used to reveal the transient microstructure of poly(L-lactide) (PLLA)/tungsten disulfide inorganic nanotubes (WS\u2082NTs) nanocomposites. This microstructure is formed during the blow molding process (\"tube expansion\") of an extruded polymer tube, an important step in the manufacturing of PLLA-based bioresorbable vascular scaffolds (BVS). A fundamental understanding of how such a microstructure develops during processing is relevant to two unmet needs in PLLA-based BVS: increasing strength to enable thinner devices and improving radiopacity to enable imaging during implantation. Here, we focus on how the flow generated during tube expansion affects the orientation of the WS\u2082NTs and the formation of polymer crystals by comparing neat PLLA and nanocomposite tubes under different expansion conditions. Surprisingly, the WS\u2082NTs remain oriented along the extrusion direction despite significant strain in the transverse direction while the PLLA crystals (c-axis) form along the circumferential direction of the tube. Although WS\u2082NTs promote the nucleation of PLLA crystals in nanocomposite tubes, crystallization proceeds with largely the same orientation as in neat PLLA tubes. We suggest that the reason for the unusual independence of the orientations of the nanotubes and polymer crystals stems from the favorable interaction between PLLA and WS\u2082NTs. This favorable interaction leads WS\u2082NTs to disperse well in PLLA and strongly orient along the axis of the PLLA tube during extrusion. As a consequence, the nanotubes are aligned orthogonally to the circumferential stretching direction, which appears to decouple the orientations of PLLA crystals and WS\u2082NTs.", "date": "2021-05-28", "date_type": "published", "publication": "Polymers", "volume": "13", "number": "11", "publisher": "MDPI", "pagerange": "Art. No. 1764", "id_number": "CaltechAUTHORS:20210603-162823845", "issn": "2073-4360", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210603-162823845", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Marie Curie Fellowship", "grant_number": "813869" }, { "agency": "Marie Curie Fellowship", "grant_number": "691238" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" }, { "agency": "Israel Science Foundation", "grant_number": "330-16" } ] }, "doi": "10.3390/polym13111764", "pmcid": "PMC8198810", "primary_object": { "basename": "polymers-13-01764.pdf", "url": "https://authors.library.caltech.edu/records/5hmwc-xne42/files/polymers-13-01764.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Rocher, Lison; Ylitalo, Andrew S.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1w7k5-09830", "eprint_id": 106966, "eprint_status": "archive", "datestamp": "2023-08-22 09:02:12", "lastmod": "2023-10-23 15:13:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Laccetti-Benjamin", "name": { "family": "Laccetti", "given": "Benjamin" }, "orcid": "0000-0002-0399-1204" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia" }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Ballistic delivery of compounds to inner layers of the cornea is limited by tough mechanical properties of stromal tissue", "ispublished": "pub", "full_text_status": "public", "keywords": "Cornea; Drug-delivery; Keratoconus; Gelatin; Penetration", "note": "\u00a9 2020 Published by Elsevier. \n\nReceived 10 July 2020, Revised 19 November 2020, Accepted 29 November 2020, Available online 5 December 2020. \n\nWe would like to acknowledge Professor Alex Groisman for getting our group started with technology for ballistics research. Also, we would like to thank Professor Guruswamy Ravichandran for fruitful discussions regarding impact mechanics. \n\nWe would like to thank Sakura Finetek for funding to complete this research. Also, we would like to thank The Jacobs Institute for Molecular Medicine for funding and the Rosen Center for Bioengineering. We would also like to thank the Caltech Biotechnology Leadership Program (a pre-doctoral program focusing on Micro/Nano medicine) for their support through NIH grant T32GM112592. \n\nData availability statement: The data that support the findings of this study are available from the corresponding author upon request. \n\nCRediT authorship contribution statement: Benjamin Laccetti: Methodology, Software, Validation, Formal analysis, Investigation, Data curation, Writing - original draft, Visualization. Julia Kornfield: Conceptualization, Writing - review & editing, Supervision, Project administration, Funding acquisition. \n\nThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\n\nSupplemental Material - 1-s2.0-S1751616120307852-mmc1.docx
", "abstract": "The barrier characteristics of the cornea are interrogated using the impact of micro-particles into ex vivo porcine cornea. Using a commercial gene gun (BioRad; PDS1000), microparticles were accelerated and made to embed in target materials: either ballistic gelatin as a reference or corneal tissue. Statistical analysis of penetration of polydisperse spherical microparticles (5\u201322 \u03bcm dia.) with density of 2.5 g/cc, 4.2 g/cc, and 7.8 g/cc (soda-lime glass, barium-titanate glass and stainless steel; more limited examination of 1.1 g/cc polyethylene and 19.2 g/cc tungsten) spanned almost two decades in kinetic energy. Penetration profiles in ballistic gelatin show that the particle embedding depth is sensitive to particle size and density. In the cornea, penetration is a weak function of size and density, and the corneal stroma is an effective stopping medium for high velocity microparticles. Despite the high water content of corneal tissue (76% w/w) compared to the stratum corneum of skin (40% w/w), the resistance to penetration of the cornea is comparable to what is seen in previous research of penetration in skin tissue. Using low density polymer particles with a therapeutic agent payload, it is demonstrated that bulk material can be ballistically delivered to the central 1 cm\u00b2 of the corneal epithelium in an even layer with high bioavailability of therapeutic compound.", "date": "2021-03", "date_type": "published", "publication": "Journal of the Mechanical Behavior of Biomedical Materials", "volume": "115", "publisher": "Elsevier", "pagerange": "Art. No. 104246", "id_number": "CaltechAUTHORS:20201208-105038922", "issn": "1751-6161", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201208-105038922", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Sakura Finetek" }, { "agency": "Joseph J. Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "Donna and Benjamin M. Rosen Bioengineering Center" }, { "agency": "NIH Predoctoral Fellowship", "grant_number": "T32GM112592" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" }, { "id": "Rosen-Bioengineering-Center" } ] }, "doi": "10.1016/j.jmbbm.2020.104246", "primary_object": { "basename": "1-s2.0-S1751616120307852-mmc1.docx", "url": "https://authors.library.caltech.edu/records/1w7k5-09830/files/1-s2.0-S1751616120307852-mmc1.docx" }, "resource_type": "article", "pub_year": "2021", "author_list": "Laccetti, Benjamin and Kornfield, Julia" }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/jf744-rkz87", "eprint_id": 107732, "eprint_status": "archive", "datestamp": "2023-08-20 01:31:12", "lastmod": "2023-10-23 16:10:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Loffredo-Fausta", "name": { "family": "Loffredo", "given": "Fausta" } }, { "id": "Tammaro-Loredana", "name": { "family": "Tammaro", "given": "Loredana" } }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "Tiziana" }, "orcid": "0000-0001-8947-0655" }, { "id": "Borriello-Carmela", "name": { "family": "Borriello", "given": "Carmela" } }, { "id": "Villani-Fulvia", "name": { "family": "Villani", "given": "Fulvia" } }, { "id": "De-Vito-Saverio", "name": { "family": "De Vito", "given": "Saverio" } }, { "id": "Ramachandran-Karthik", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing", "ispublished": "pub", "full_text_status": "public", "keywords": "Poly(lactic acid) (PLA), Tungsten disulfide (WS2) nanotubes, Nanocomposites, Strain-induced\ncrystallization, Uniaxial deformation, Raman spectroscopy", "note": "\u00a9 2021 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. \n\nReceived 23 October 2020; Accepted 03 January 2021; Published 26 January 2021.\n\nThe authors kindly acknowledge the Department of Industrial Engineering, (Prof. Giuliana Gorrasi), University of Salerno, Italy for the support in the tensile tests. Steven Weigand, beamline scientist at Beamline 5-ID-D of the APS at ANL, is especially acknowledged for his support with WAXS data collection and analysis. Dr. Alla Zak (Holon Institute of Technology) is acknowledged for providing a special purchase price of the WS_2 NTs from NanoMaterials in 2011 and useful discussions on their purification and dispersion. \n\nThis project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk\u0142odowska-Curie grant agreement No 691238, the Jacobs Institute for Molecular Engineering for Medicine at the California Institute of Technology, and the National Heart, Lung, And Blood Institute of the National Institutes of Health under Award Number F31HL137308. \n\nAvailability of data and materials: Not applicable. \n\nAuthor Contributions: Di Luccio and Kornfield designed the research, Di Luccio coordinated the activities. Tammaro manufactured the samples. Tammaro, Borriello, Villani, Loffredo, Ramachandran and Di Luccio performed experiments and analyzed the data. De Vito developed the code for Raman data analysis. All the authors reviewed and approved the manuscript. \n\nThe authors declare that they have no competing interests.\n\nPublished - Loffredo2021_Article_EffectOfTungstenDisulfideNanot.pdf
Supplemental Material - Images_1-13.zip
", "abstract": "Tungsten disulfide (WS\u2082) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS\u2082 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS\u2082 nanocomposite films varying the concentration of WS\u2082 NTs from 0 (neat PLA) to 0.6\u2009wt%. The films were uniaxially drawn at 90\u2009\u00b0C and annealed at the same temperature for 3 and 10\u2009min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS\u2082 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6\u2009wt% of WS\u2082 induces the same level of crystallinity in as stretched PLA-WS\u2082 as annealing in neat PLA for 10\u2009min. These data provide useful insights into the role of WS\u2082 NTs on the structural evolution of PLA-WS\u2082 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.", "date": "2021-01-26", "date_type": "published", "publication": "Functional Composite Materials", "volume": "2", "number": "1", "publisher": "Springer Science and Business Media LLC", "pagerange": "Art. No. 3", "id_number": "CaltechAUTHORS:20210126-142455748", "issn": "2522-5774", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210126-142455748", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Marie Curie Fellowship", "grant_number": "691238" }, { "agency": "Joseph J. Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "NIH Postdocotral Fellowship", "grant_number": "F31HL137308" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.1186/s42252-021-00016-2", "pmcid": "PMC8198810", "primary_object": { "basename": "Images_1-13.zip", "url": "https://authors.library.caltech.edu/records/jf744-rkz87/files/Images_1-13.zip" }, "related_objects": [ { "basename": "Loffredo2021_Article_EffectOfTungstenDisulfideNanot.pdf", "url": "https://authors.library.caltech.edu/records/jf744-rkz87/files/Loffredo2021_Article_EffectOfTungstenDisulfideNanot.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Loffredo, Fausta; Tammaro, Loredana; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/skcvm-qcc32", "eprint_id": 106967, "eprint_status": "archive", "datestamp": "2023-08-22 08:32:37", "lastmod": "2023-10-23 15:13:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Moln\u00e1r-Krist\u00f3f", "name": { "family": "Molnar", "given": "Kristof" }, "orcid": "0000-0002-5393-2130" }, { "id": "Helfer-Carin-A", "name": { "family": "Helfer", "given": "Carin A." }, "orcid": "0000-0003-4550-4942" }, { "id": "Kaszas-Gabor", "name": { "family": "Kaszas", "given": "Gabor" } }, { "id": "Krisch-Eniko", "name": { "family": "Krisch", "given": "Eniko" } }, { "id": "Chen-Dongjie", "name": { "family": "Chen", "given": "Dongjie" } }, { "id": "McKenna-Gregory-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Puskas-Judit-E", "name": { "family": "Puskas", "given": "Judit E." }, "orcid": "0000-0001-5282-5256" } ] }, "title": "Liquid chromatography at critical conditions (LCCC): Capabilities and limitations for polymer analysis", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Liquid chromatography; Sensitivity; Poly(3,6-dioxa-1,8-octanedithiol); Critical conditions; Polyisobutylene; Disulfide cyclic polymers", "note": "\u00a9 2020 Published by Elsevier. \n\nReceived 8 September 2020, Revised 27 October 2020, Accepted 2 December 2020, Available online 5 December 2020. \n\nThe Authors would like to thank Dr. Prajakatta Mulay, Mauricio Azevedo de Freitas and Andres Munoz Salgado for their contribution to this work. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0018891. \n\nAuthor Contributions: Kristof Molnar \u2013 Investigation, formal analysis, Writing - Original Draft, Writing - Review & Editing Carin A. Helfer \u2013 Investigation, formal analysis, Writing - Original Draft, Gabor Kaszas - Investigation, formal analysis Eniko Krisch - Writing - Original Draft, Writing - Review & Editing, Visualization Dongjie Chen \u2013 Writing - Original Draft, Writing - Review & Editing Gregory B. McKenna \u2013 Writing - Original Draft, Writing - Review & Editing, Funding aquisition, Supervision Julia A. Kornfield - Writing - Original Draft, Writing - Review & Editing, Supervision, Funding aquisition, Judit E. Puskas - Writing - Original Draft, Writing - Review & Editing, Funding aquisition, Supervision.", "abstract": "This paper investigates liquid chromatography at critical condition (LCCC) for polymer analysis. Based on controversial claims on the separation of cyclic polymers from linear analogues in the literature, the efficiency of LCCC for separation and purity analysis is questioned. Polyisobutylene (PIB) and poly(3,6-dioxa-1,8-octanedithiols) (polyDODT) were used for the study. The structure of low molecular weight cyclic and linear polyDODT was demonstrated by MALDI-ToF. NMR did not show the presence of thiol end groups in higher molecular weight PIB-disulfide and polyDODT samples, so they were considered cyclic polymers. When a low molecular weight polyDODT oligomer with only traces of cycles, as demonstrated by MALDI-ToF, was mixed with an M_n = 27 K g/mol cyclic sample, LCCC did not detect the presence of linear oligomers at 6 wt%. Based on the data presented here, it can be concluded that the LCCC method is not capable of measuring <6 wt% linear contamination so earlier claims for cyclic polystyrene (PS) samples purified by LCCC having <3% linear contaminants are questioned.", "date": "2021-01-15", "date_type": "published", "publication": "Journal of Molecular Liquids", "volume": "322", "publisher": "Elsevier", "pagerange": "Art. No. 114956", "id_number": "CaltechAUTHORS:20201208-105039049", "issn": "0167-7322", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201208-105039049", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0018891" } ] }, "doi": "10.1016/j.molliq.2020.114956", "resource_type": "article", "pub_year": "2021", "author_list": "Molnar, Kristof; Helfer, Carin A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/x6dw3-hp957", "eprint_id": 105456, "eprint_status": "archive", "datestamp": "2023-08-19 21:42:24", "lastmod": "2023-10-20 22:00:57", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhou-Dan", "name": { "family": "Zhou", "given": "Dan" } }, { "id": "Chwa-Marilyn", "name": { "family": "Chwa", "given": "Marilyn" } }, { "id": "Shao-Zixuan", "name": { "family": "Shao", "given": "Zixuan" } }, { "id": "Koo-Jin-Mo", "name": { "family": "Koo", "given": "Jin Mo" } }, { "id": "Park-John-Y", "name": { "family": "Park", "given": "John Y." } }, { "id": "Karageozian-H-L", "name": { "family": "Karageozian", "given": "Hampar L." } }, { "id": "Karageozian-V-H", "name": { "family": "Karageozian", "given": "Vicken H." } }, { "id": "Kenney-C-M", "name": { "family": "Kenney", "given": "Cristina M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Mechanism of Action of Risuteganib for Retinal Diseases through Protection of Retinal Pigment Epithelium (RPE) and Enhancement of Mitochondrial Functions", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 Association for Research in Vision and Ophthalmology.\nThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.\n\nPublished - Zhou_2020p4949.pdf
", "abstract": "Purpose : Risuteganib is a novel synthetic peptide that has advanced through Phase II clinical trials, showing promising efficacy in retinal diseases, including dry age-related macular degeneration (AMD) and diabetic macular edema (DME). This study is to explore the mechanism of action (MOA) of risuteganib by uncovering its functional target(s) and the associated cell layer. \n\nMethods : Fluorescent staining of mouse and rat retinal cryo-sections was performed with risuteganib-dye conjugates and compared with control peptide. Protective effects against oxidative stress was studied in ARPE-19 cell line challenged with tert-Butyl Hydroperoxide (tBHP) using WST-1 assay and Caspase 3/7 apoptosis assay. Mitochondrial bioenergetics were measured using Seahorse XF cell mito stress test. \n\nResults : Peptide-dye staining of animal retinal tissue indicated preferential localization of risuteganib in the RPE layer. 24hr risuteganib pretreatment significantly rescued ARPE-19 cells from tBHP-induced oxidative stress in WST-1 assay (p<0.05) and Caspase 3/7 apoptosis assay (p<0.01). Seahorse bioenergetics measurement of ARPE-19 cells showed that risuteganib dose-dependently enhanced mitochondrial basal, maximal and ATP-related respirations of RPE cells. \n\nConclusions : Oxidative stress is one of the hallmarks of retinal diseases AMD and DME, and is associated with impaired RPE function. The observations of preferential binding to RPE layers in retina and the protection of mitochondrial function in RPE cells against oxidative stress in vitro, suggest that the clinically observed therapeutic effect of risuteganib in dry AMD and DME may be associated with supporting RPE cells and maintaining mitochondrial stability and function. Such a novel MOA of risuteganib could lead to new strategies for treatment of retinal diseases.", "date": "2020-06", "date_type": "published", "publication": "Investigative Ophthalmology and Visual Science", "volume": "61", "number": "7", "publisher": "Association for Research in Vision and Ophthalmology", "pagerange": "Art. No. 4949", "id_number": "CaltechAUTHORS:20200921-110447558", "issn": "0146-0404", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200921-110447558", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "primary_object": { "basename": "Zhou_2020p4949.pdf", "url": "https://authors.library.caltech.edu/records/x6dw3-hp957/files/Zhou_2020p4949.pdf" }, "resource_type": "article", "pub_year": "2020", "author_list": "Zhou, Dan; Chwa, Marilyn; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/nma9s-5dx48", "eprint_id": 105460, "eprint_status": "archive", "datestamp": "2023-08-19 21:42:29", "lastmod": "2023-10-20 22:01:17", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Maturi-Raj", "name": { "family": "Maturi", "given": "Raj" } }, { "id": "Jaffe-G-J", "name": { "family": "Jaffe", "given": "Glenn J." } }, { "id": "Ehlers-J-P", "name": { "family": "Ehlers", "given": "Justis P." } }, { "id": "Kaiser-P-K", "name": { "family": "Kaiser", "given": "Peter K." } }, { "id": "Boyer-D-S", "name": { "family": "Boyer", "given": "David S." } }, { "id": "Heier-J-S", "name": { "family": "Heier", "given": "Jeffrey S." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kuppermann-B-D", "name": { "family": "Kuppermann", "given": "Baruch D." } }, { "id": "Quiroz-Mercado-H", "name": { "family": "Quiroz-Mercado", "given": "Hugo" } }, { "id": "Aubel-J", "name": { "family": "Aubel", "given": "Janine" } }, { "id": "Karageozian-L", "name": { "family": "Karageozian", "given": "Lisa" } }, { "id": "Karageozian-V-H", "name": { "family": "Karageozian", "given": "Vicken H." } }, { "id": "Sarayba-M", "name": { "family": "Sarayba", "given": "Melvin" } } ] }, "title": "Safety and Efficacy of Risuteganib in Intermediate Non-exudative Age-Related Macular Degeneration", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 Association for Research in Vision and Ophthalmology.\nThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.\n\nPublished - Maturi_2020p1944.pdf
", "abstract": "Purpose : Risuteganib is a small synthetic peptide that regulates select integrin functions involved in the pathogenesis of dry age-related macular degeneration (AMD). This study evaluated the safety and efficay of risuteganib for the treatment of dry AMD. \n\nMethods : Randomized, double-masked, placebo-controlled Phase 2 study in eyes with intermediate dry AMD presenting with best-corrected visual acuity (BCVA) between 20/40-20/200 was conducted across multiple centers in the United States. Patients were randomized to receive either intravitreal 1.0mg risuteganib or sham injection at baseline. At week 16, patients in the risuteganib group received a second dose and the sham group crossed over and receive a single dose of 1.0mg risuteganib. The primary endpoint was the percentage of population with \u2265 8 letters BCVA gain from baseline to week 28 in 1.0mg risuteganib vs baseline to week 12 for sham. \n\nResults : Forty-five patients were enrolled in the study. At baseline, mean patient age was 78.8 and 75.9 years and mean baseline BCVA was 67.1 and 64.4 letters in the sham and risuteganib groups, respectively. The primary endpoint was met; 48% of patients in the risuteganib group at week 28 and 7% of patients in the sham group at week 12 gained > 8 letters from baseline (p=0.013). Of the risuteganib treated patients, 20% gained > 15 letters at week 28; no patients in the sham group at week 12 had this gain. On a post-hoc masked analysis by 2 independent reading centers, greater outer retinal and photoreceptor thickness and volume and smaller ellipsoid zone defect area in the central 1 mm zone at baseline were associated with increased BCVA response to risuteganib. Risuteganib demonstrated a good safety profile in this study. \n\nConclusions : Risuteganib showed significant benefit over sham in patients with dry AMD with respect to proportion of patients gaining > 8 letters of BCVA from baseline. Furthermore, post hoc analysis provides preliminary insights into baseline anatomic features that may help to determine likelihood of BCVA response to risuteganib. These findings will be confirmed in an upcoming larger trial.", "date": "2020-06", "date_type": "published", "publication": "Investigative Ophthalmology and Visual Science", "volume": "61", "number": "7", "publisher": "Association for Research in Vision and Ophthalmology", "pagerange": "Art. No. 1944", "id_number": "CaltechAUTHORS:20200921-142348069", "issn": "0146-0404", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200921-142348069", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "primary_object": { "basename": "Maturi_2020p1944.pdf", "url": "https://authors.library.caltech.edu/records/nma9s-5dx48/files/Maturi_2020p1944.pdf" }, "resource_type": "article", "pub_year": "2020", "author_list": "Maturi, Raj; Jaffe, Glenn J.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6zsvy-3g175", "eprint_id": 107842, "eprint_status": "archive", "datestamp": "2023-08-19 21:00:19", "lastmod": "2023-12-22 23:10:29", "type": "patent", "metadata_visibility": "show", "creators": { "items": [ { "id": "Faber-K-T", "name": { "family": "Faber", "given": "Katherine T." }, "orcid": "0000-0001-6585-2536" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Arai-Noriaki", "name": { "family": "Arai", "given": "Noriaki" }, "orcid": "0000-0002-3040-2997" }, { "id": "Bateman-Orland", "name": { "family": "Bateman", "given": "Orland" } }, { "id": "Ismagilov-R-F", "name": { "family": "Ismagilov", "given": "Rustem F." }, "orcid": "0000-0002-3680-4399" } ] }, "title": "Freeze-cast ceramic membrane for size based filtration", "ispublished": "unpub", "full_text_status": "public", "note": "2018-08-24: Priority to US201862722689P.\n2019-08-23: Application filed by California Institute of Technology.\n2020-04-16: Publication of US20200115291A1\n\nPublished - US20200115291A1.pdf
Published - WO2020041759A1.pdf
", "abstract": "Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.", "date": "2020-04-16", "date_type": "published", "publisher": "U.S. Patent Office", "id_number": "CaltechAUTHORS:20210201-150525983", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210201-150525983", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "local_group": { "items": [ { "id": "Division-of-Biology-and-Biological-Engineering" } ] }, "primary_object": { "basename": "US20200115291A1.pdf", "url": "https://authors.library.caltech.edu/records/6zsvy-3g175/files/US20200115291A1.pdf" }, "related_objects": [ { "basename": "WO2020041759A1.pdf", "url": "https://authors.library.caltech.edu/records/6zsvy-3g175/files/WO2020041759A1.pdf" } ], "resource_type": "patent", "pub_year": "2020", "author_list": "Faber, Katherine T.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6ycbs-adv63", "eprint_id": 94096, "eprint_status": "archive", "datestamp": "2023-08-19 15:09:00", "lastmod": "2023-10-20 17:40:30", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Mitigating post-impact energy release from liquid fuels", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2019 American Chemical Society.", "abstract": "Impacts that target fuel depots, fuel tanker trucks or rail cars, or the fuel tanks of vehicles, in addn. to impacts that use a fully fueled vehicle as a weapon, inflict greater damage by rapidly releasing much of the energy content of the fuel. Here, high-performance polymers are used to inhibit misting of fuel following impact to mitigate fuel explosion/conflagration. The approach is complementary to strategies that modify materials of construction of vehicles or buildings. Polymers added to fuel can mitigate impact-induced damage even when it is not possible to retrofit existing equipment or structures. Mist control polymers are complementary to approaches that provide fire retardant when impact is detected. Mist control polymers dissolved in fuel function through their innate response to rapid elongational deformation and do not require sensors or control devices to activate their response. The present polymers overcome prior obstacles to mist control fuel additives: 1) they do not degrade during transport of fuel through pumps and pipelines; 2) they remain sol. at low temps. (down to the f.p. of kerosene); 3) they are compatible with necessary fuel processing (filtering and dewatering); and 4) they burn in unmodified engines without measurably affecting power output or fuel efficiency. This combination of attributes was guided by theor. predictions of the mol. structure and concn. range in which end-to-end assocn. of polymers could produce a significant population of supramols. having mol. wt. greater than 5 Mg/mol, referred to as \"megasupramols.\" This talk will summarize the theor. basis for the mol. design, the synthetic route to the polymers and characterization of their mol. structure, their rheol. properties in shear flow, and their performance in various fuel tests, including qual. observations regarding post impact misting, ignition and flame propagation.", "date": "2019-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20190325-090635232", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190325-090635232", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2019", "author_list": "Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/e008j-adv88", "eprint_id": 89697, "eprint_status": "archive", "datestamp": "2023-08-19 11:54:51", "lastmod": "2023-10-18 22:55:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ramachandran-Karthik", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "Tiziana" }, "orcid": "0000-0001-8947-0655" }, { "id": "Ailianou-Artemis", "name": { "family": "Ailianou", "given": "Artemis" } }, { "id": "Kossuth-Mary-Beth", "name": { "family": "Kossuth", "given": "Mary Beth" } }, { "id": "Oberhauser-James-P", "name": { "family": "Oberhauser", "given": "James P." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Crimping-induced structural gradients explain the lasting strength of poly L-lactide bioresorbable vascular scaffolds during hydrolysis", "ispublished": "pub", "full_text_status": "public", "keywords": "PLLA | hydrolysis | coronary heart disease | BVS | X-ray microdiffraction", "note": "\u00a9 2018 The Author(s). Published under the PNAS license. \n\nEdited by Frank S. Bates, University of Minnesota, Minneapolis, MN, and approved August 17, 2018 (received for review May 9, 2018). PNAS published ahead of print September 17, 2018 https://doi.org/10.1073/pnas.1807347115 \n\nWe thank Dr. Zhonghou Cai (Advanced Photon Source, APS) for his assistance in collecting X-ray microdiffraction data and Troy Carter (Abbott Vascular) for sectioning the scaffolds. This research used resources of the APS, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357. This work was supported by Abbott Vascular, the Jacobs Institute for Molecular Engineering for Medicine, and the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award F31HL137308. \n\nAuthor contributions: K.R. and J.A.K. designed research; K.R. and T.D.L. performed research; A.A., M.B.K., and J.P.O. contributed new reagents/analytic tools; K.R. and J.A.K. analyzed data; and K.R. and J.A.K. wrote the paper. \n\nConflict of interest statement: M.B.K. and J.P.O. are employees of Abbott Vascular. Funding for this research was provided by Abbott Vascular. \n\nThis article is a PNAS Direct Submission. \n\nThis article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1807347115/-/DCSupplemental.\n\nPublished - 10239.full.pdf
Supplemental Material - pnas.1807347115.sapp.pdf
", "abstract": "Biodegradable polymers open the way to treatment of heart disease using transient implants (bioresorbable vascular scaffolds, BVSs) that overcome the most serious complication associated with permanent metal stents\u2014late stent thrombosis. Here, we address the long-standing paradox that the clinically approved BVS maintains its radial strength even after 9 mo of hydrolysis, which induces a \u223c40% decrease in the poly L-lactide molecular weight (Mn). X-ray microdiffraction evidence of nonuniform hydrolysis in the scaffold reveals that regions subjected to tensile stress during crimping develop a microstructure that provides strength and resists hydrolysis. These beneficial morphological changes occur where they are needed most\u2014where stress is localized when a radial load is placed on the scaffold. We hypothesize that the observed decrease in Mn reflects the majority of the material, which is undeformed during crimping. Thus, the global measures of degradation may be decoupled from the localized, degradation-resistant regions that confer the ability to support the artery for the first several months after implantation.", "date": "2018-10-09", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "115", "number": "41", "publisher": "National Academy of Sciences", "pagerange": "10239-10244", "id_number": "CaltechAUTHORS:20180918-095157859", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180918-095157859", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-06CH11357" }, { "agency": "Abbott Vascular" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "NIH Postdoctoral Fellowship", "grant_number": "F31HL137308" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.1073/pnas.1807347115", "pmcid": "PMC6187115", "primary_object": { "basename": "10239.full.pdf", "url": "https://authors.library.caltech.edu/records/e008j-adv88/files/10239.full.pdf" }, "related_objects": [ { "basename": "pnas.1807347115.sapp.pdf", "url": "https://authors.library.caltech.edu/records/e008j-adv88/files/pnas.1807347115.sapp.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Ramachandran, Karthik; Di Luccio, Tiziana; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8yh9d-1j412", "eprint_id": 87770, "eprint_status": "archive", "datestamp": "2023-08-21 23:41:21", "lastmod": "2024-01-14 20:24:24", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tammaro-L", "name": { "family": "Tammaro", "given": "Loredana" } }, { "id": "Di-Luccio-T", "name": { "family": "Di Luccio", "given": "Tiziana" }, "orcid": "0000-0001-8947-0655" }, { "id": "Borriello-C", "name": { "family": "Borriello", "given": "Carmella" } }, { "id": "Loffredo-F", "name": { "family": "Loffredo", "given": "Fausta" } }, { "id": "Ramachandran-K", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Villani-F", "name": { "family": "Villani", "given": "Fulvia" } }, { "id": "Di-Benedetto-F", "name": { "family": "Di Benedetto", "given": "Francesca" } }, { "id": "Schiller-T", "name": { "family": "Schiller", "given": "Tara" } }, { "id": "Minarini-C", "name": { "family": "Minarini", "given": "Carla" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Effect of tungsten disulfide (WS_2) nanotubes on structural, morphological and mechanical properties of poly(L-lactide) (PLLA) films", "ispublished": "unpub", "full_text_status": "public", "keywords": "Polylactide; tungsten disulfide nanotubes; nanocomposites; bioresorbable vascular scaffolds", "note": "\u00a9 2018 AIP Publishing. \n\nThis work was supported by the Marie Curie RISE action Bi-Stretch-4-Biomed project (G.A. n. 691238).\n\nPublished - 1.5045935.pdf
", "abstract": "Poly(L-lactide) (PLLA) is a semicrystalline, biocompatible and biodegradable polymer widely employed in many applications (food packaging, biomedical devices, drug delivery systems). This work deals with nanocomposites of PLLA and tungsten disulfide (WS_2) nanotubes (NTs) as a novel material to obtain thinner and stronger bioresorbable vascular scaffolds. We studied the influence of WS_2 NTs on the mechanical properties of PLLA-WS_2 films. Polarized optical microscopy reveals a high degree of orientation of the polymer molecules in stretched films that further increases with a post-stretching annealing treatment. At the same time, X-ray diffraction (XRD) and Raman spectroscopy confirm enhancement of the crystallinity induced by the WS_2 NTs.", "date": "2018-07-11", "date_type": "published", "publisher": "American Institute of Physics", "place_of_pub": "Melville, NY", "pagerange": "Art. No. 020073", "id_number": "CaltechAUTHORS:20180711-145601857", "isbn": "978-0-7354-1697-0", "book_title": "9th International Conference on \"Times of Polymers and Composites\"", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180711-145601857", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Marie Curie Fellowship", "grant_number": "691238" } ] }, "contributors": { "items": [ { "id": "D'Amore-A", "name": { "family": "D'Amore", "given": "Alberto" } }, { "id": "Acierno-D", "name": { "family": "Acierno", "given": "Domenico" } }, { "id": "Grassia-L", "name": { "family": "Grassia", "given": "Luigi" } } ] }, "doi": "10.1063/1.5045935", "primary_object": { "basename": "1.5045935.pdf", "url": "https://authors.library.caltech.edu/records/8yh9d-1j412/files/1.5045935.pdf" }, "resource_type": "book_section", "pub_year": "2018", "author_list": "Tammaro, Loredana; Di Luccio, Tiziana; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/hz0qx-6ct32", "eprint_id": 89962, "eprint_status": "archive", "datestamp": "2023-08-19 10:05:36", "lastmod": "2023-10-18 23:07:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Quiroz-Mercado-H", "name": { "family": "Quiroz-Mercado", "given": "Hugo" } }, { "id": "Boyer-D-S", "name": { "family": "Boyer", "given": "David S." } }, { "id": "Campochiaro-P-A", "name": { "family": "Campochiaro", "given": "Peter A." } }, { "id": "Heier-J-S", "name": { "family": "Heier", "given": "Jeffrey S." } }, { "id": "Kaiser-P-K", "name": { "family": "Kaiser", "given": "Peter K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julie" }, "orcid": "0000-0001-6746-8634" }, { "id": "Kuppermann-B-D", "name": { "family": "Kuppermann", "given": "Baruch D." } }, { "id": "Karageozian-V-H", "name": { "family": "Karageozian", "given": "Vicken H." } }, { "id": "Karageozian-H-L", "name": { "family": "Karageozian", "given": "Hampar L." } }, { "id": "Karageozian-L", "name": { "family": "Karageozian", "given": "Lisa" } }, { "id": "Park-John-Y", "name": { "family": "Park", "given": "John Y." } }, { "id": "Sarayba-M", "name": { "family": "Sarayba", "given": "Melvin" } } ] }, "title": "Randomized, Prospective, Double-Masked, Controlled Phase 2b Trial to Evaluate the Safety & Efficacy of ALG-1001 (Luminate\u00ae) in Diabetic Macular Edema", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. \n\nCommercial Relationships Hugo Quiroz-Mercado, Allegro Ophthalmics (I), Allegro Ophthalmics (C); David Boyer, Aerpio (F), Aerpio (C), Allegro Ophthalmics (I), Allegro Ophthalmics (C), Allergan (F), Allergan (C), Bayer (F), Bayer (C), Boehringer-Ingelheim (F), Boehringer-Ingelheim (C), Genentech (F), Genentech (C), Novartis (F), Novartis (C), Nuerotech (I), Nuerotech (C), Ohr (I), Ohr (C), Ophthotech (I), Regeneron (F), Regeneron (C), River Vision (F), River Vision (C), Roche (F), Roche (C); Peter Campochiaro, Aerpio (F), Aerpio (C), Alimera (F), Alimera (C), Allegro Ophthalmics (F), Allegro Ophthalmics (I), Allegro Ophthalmics (C), Allergan (F), Allergan (C), Applied Genetic Technologies (C), AsclipiX (F), AsclipiX (C), Genentech/Roch (C), Genentech/Roche (F), Genzyme (F), GlaxoSmithKline (F), Graybug (I), Intrexon (C), Merck (C), Oxford Biomedica (F), Regeneron (F), Regenxbio (F), Regenxbio (C), Rxi (F), Rxi (C); Jeffrey Heier, Aerpio (F), Aerpio (C), Allegro Ophthalmics (I), Asclepix (C), Bayer (C), Daiichi-Sankyo (C), Daiichi-Sankyo (F), Genentech/Roche (C), Genentech/Roche (F), Novartis (C), Regeneron (C), Regeneron (F), SciFluor (C), SciFluor (F); Peter Kaiser, Aerie (C), Aerpio (C), Alcon (C), Allegro Ophthalmics (I), Allegro Ophthalmics (C), Allergan (C), Bayer (C), Biogen Idec (C), Boerenger Ingelheim (C), Galecto Biotech (C), Hospira (C), jCyte (C), Kanghong (C), Kodiak (C), Novartis (C), Ohr (C), Omeros (C), Regeneron (C), Retinal Sciences (C), Santen (C), SciFluor (C), Shire (C), Stealth Biotherapeutics (C), Thrombogenics (C); Julie Kornfield, Allegro Ophthalmics (I), Allegro Ophthalmics (C); Baruch Kuppermann, Aerpio (C), Alcon (C), Alcon (F), Alimera (C), Alimera (F), Allegro Ophthalmics (F), Allegro Ophthalmics (I), Allegro Ophthalmics (C), Allergan (C), Allergan (F), Ampio (C), Catalyst (C), Dose (C), Eyedaptic (C), Genentech (F), Genetech (C), Glaukos (C), Ionis (C), J-Cyte (C), J-Cyte (F), Novartis (C), Ophthotech (C), Ophthotech (F), Regeneron (C), Regeneron (F); Vicken Karageozian, Allegro Ophthalmics (I), Allegro Ophthalmics (E); Hampar Karageozian, Allegro Ophthalmics (I), Allegro Ophthalmics (E); Lisa Karageozian, Allegro Ophthalmics (I), Allegro Ophthalmics (E); John Park, Allegro Ophthalmics (I), Allegro Ophthalmics (E); Melvin Sarayba, Allegro Ophthalmics (I), Allegro Ophthalmics (E). \n\nSupport: None.", "abstract": "Purpose : Currently, there is only one predominant treatment paradigm for diabetic macular edema (DME): anti-VEGF agent as first line, followed by corticosteroids as second line. We performed a double-masked, placebo-controlled, randomized multi-center phase 2b trial to evaluate the safety & efficacy of ALG-1001, a novel first-in-class integrin inhibitor, as compared to bevacizumab in DME.\n\nMethods : 80 subjects were randomly assigned to 5 treatment groups: 1.25mg bevacizumab control arm of 5 monthly injections (Group 1); single treatment of 1.25mg bevacizumab at week 0 followed by three ALG-1001 injections (1.0mg or 0.5mg) at weeks 1, 4 and 8 (Groups 2 & 3); ALG-1001 (1.0mg or 0.5mg) given in direct combination with bevacizumab 1.25mg at weeks 1, 4 and 8 (Groups 4 & 5). Efficacy outcomes were change from baseline in BCVA and OCT CMT at week 20.\n\nResults : 65 subjects were included in the per protocol population. Group 2 demonstrated the best efficacy among the ALG-1001 groups. Mean change in BCVA were 6.7 and 7.1 letters for 1.25mg bevacizumab and ALG-1001 1.0mg in sequential treatment, respectively. BCVA improved earlier than CMT improvements suggesting a new mechanism of action unlike anti-VEGF. There were no drug related SAEs in ALG-1001 groups.\n\nConclusions : Primary endpoint of non-inferiority in BCVA was met with sequential dosing of a single bevacizumab treatment plus 3 doses of 1.0mg ALG-1001 vs 6 doses of 1.25 mg bevacizumab (\u22643 letters difference) at week 20. ALG-1001 showed 12-week durability in all study subjects in sequential therapy arms.", "date": "2018-07", "date_type": "published", "publication": "Investigative Ophthalmology and Visual Science", "volume": "59", "number": "9", "publisher": "Association for Research in Vision and Ophthalmology (ARVO)", "pagerange": "Art. No. 1960", "id_number": "CaltechAUTHORS:20180926-125651369", "issn": "0146-0404", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180926-125651369", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2018", "author_list": "Quiroz-Mercado, Hugo; Boyer, David S.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/smxpk-3jw68", "eprint_id": 86115, "eprint_status": "archive", "datestamp": "2023-08-21 22:56:37", "lastmod": "2023-10-18 19:15:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ramachandran-Karthik", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Miscioscia-Riccardo", "name": { "family": "Miscioscia", "given": "Riccardo" }, "orcid": "0000-0001-6586-4182" }, { "id": "De-Filippo-Giovanni", "name": { "family": "De Filippo", "given": "Giovanni" } }, { "id": "Pandolfi-Giuseppe", "name": { "family": "Pandolfi", "given": "Giuseppe" } }, { "id": "Di-Luccio-Tiziana", "name": { "family": "Di Luccio", "given": "Tiziana" }, "orcid": "0000-0001-8947-0655" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Tube Expansion Deformation Enables In Situ Synchrotron X-ray Scattering Measurements during Extensional Flow-Induced Crystallization of Poly l-Lactide Near the Glass Transition", "ispublished": "pub", "full_text_status": "public", "keywords": "PLLA; bioresorbable vascular scaffolds; stretch blow molding; biaxial elongation; SAXS; WAXS", "note": "\u00a9 2018 The Author(s). Licensee MDPI, Basel, Switzerland. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0). \n\nReceived: 11 February 2018 / Revised: 4 March 2018 / Accepted: 6 March 2018 / Published: 8 March 2018. \n\n(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers) \n\nThis research used resources of the Advanced Photon Source (APS), a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357. The authors acknowledge all the staff at beamline 5-ID-D DND-CAT of the Advanced Photon Source (APS) at the Argonne National Laboratories, especially Steven Weigand and James Rix for their support before and during the synchrotron experiments. The authors acknowledge Mary Beth Kossuth at Abbott Vascular for providing the preforms. KR and TDL are very thankful to Giuseppe Nenna at ENEA for useful discussions on ray tracing calculations. This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sk\u0142odowska-Curie grant agreement No 691238, the Jacobs Institute for Molecular Engineering for Medicine at the California Institute of Technology, and the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Number F31HL137308. \n\nAuthor Contributions: Karthik Ramachandran and Julia A. Kornfield designed research; Karthik Ramachandran, Riccardo Miscioscia, Giovanni De Filippo, Giuseppe Pandolfi and Tiziana Di Luccio performed research; Karthik Ramachandran, Riccardo Miscioscia, Tiziana Di Luccio and Julia A. Kornfield analyzed data; and Karthik Ramachandran, Riccardo Miscioscia, Tiziana Di Luccio and Julia A. Kornfield wrote the paper. \n\nThe authors declare no conflict of interest.\n\nPublished - polymers-10-00288.pdf
Supplemental Material - polymers-10-00288-s001.pdf
", "abstract": "Coronary Heart Disease (CHD) is one of the leading causes of death worldwide, claiming over seven million lives each year. Permanent metal stents, the current standard of care for CHD, inhibit arterial vasomotion and induce serious complications such as late stent thrombosis. Bioresorbable vascular scaffolds (BVSs) made from poly l-lactide (PLLA) overcome these complications by supporting the occluded artery for 3\u20136 months and then being completely resorbed in 2\u20133 years, leaving behind a healthy artery. The BVS that recently received clinical approval is, however, relatively thick (~150 \u00b5m, approximately twice as thick as metal stents ~80 \u00b5m). Thinner scaffolds would facilitate implantation and enable treatment of smaller arteries. The key to a thinner scaffold is careful control of the PLLA microstructure during processing to confer greater strength in a thinner profile. However, the rapid time scales of processing (~1 s) defy prediction due to a lack of structural information. Here, we present a custom-designed instrument that connects the strain-field imposed on PLLA during processing to in situ development of microstructure observed using synchrotron X-ray scattering. The connection between deformation, structure and strength enables processing\u2013structure\u2013property relationships to guide the design of thinner yet stronger BVSs", "date": "2018-03-08", "date_type": "published", "publication": "Polymers", "volume": "10", "number": "3", "publisher": "MDPI", "pagerange": "Art. No. 288", "id_number": "CaltechAUTHORS:20180430-101112370", "issn": "2073-4360", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180430-101112370", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-06CH11357" }, { "agency": "Marie Curie Fellowship", "grant_number": "691238" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "NIH Postdocotral Fellowship", "grant_number": "F31HL137308" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.3390/polym10030288", "pmcid": "PMC6415077", "primary_object": { "basename": "polymers-10-00288-s001.pdf", "url": "https://authors.library.caltech.edu/records/smxpk-3jw68/files/polymers-10-00288-s001.pdf" }, "related_objects": [ { "basename": "polymers-10-00288.pdf", "url": "https://authors.library.caltech.edu/records/smxpk-3jw68/files/polymers-10-00288.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Ramachandran, Karthik; Miscioscia, Riccardo; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/03p8a-r1p62", "eprint_id": 82831, "eprint_status": "archive", "datestamp": "2023-08-19 06:07:19", "lastmod": "2023-10-17 22:42:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wingstrand-S-L", "name": { "family": "Wingstrand", "given": "Sara L." }, "orcid": "0000-0002-4555-4571" }, { "id": "Shen-Bo", "name": { "family": "Shen", "given": "Bo" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Mortensen-K", "name": { "family": "Mortensen", "given": "Kell" } }, { "id": "Parisi-D", "name": { "family": "Parisi", "given": "Daniele" } }, { "id": "Vlassopoulos-D", "name": { "family": "Vlassopoulos", "given": "Dimitris" } }, { "id": "Hassager-O", "name": { "family": "Hassager", "given": "Ole" }, "orcid": "0000-0003-2695-6791" } ] }, "title": "Rheological Link Between Polymer Melts with a High Molecular Weight Tail and Enhanced Formation of Shish-Kebabs", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: September 15, 2017; Accepted: October 26, 2017; Publication Date (Web): October 31, 2017. \n\nThe authors thank Aage og Johanne Louis-Hansen fonden for financial support. Furthermore, we thank Qian Huang and Prof. Nicolas J. Alvarez for fruitful discussions on the work. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - mz7b00718_si_001.pdf
", "abstract": "Presence of an ultra high molecular weight (UHMw) fraction in flowing polymer melts is known to facilitate formation of oriented crystalline structures significantly. The UHMw fraction manifests itself as a minor tail in the molar mass distribution and is hardly detectable in the canonical characterization methods. In this study, alternatively, we demonstrate how the nonlinear extensional rheology reveals to be a very sensitive characterization tool for investigating the effect of the UHMw-tail on the structural ordering mechanism. Samples containing a UHMw-tail relative to samples without, exhibit a clear increase in extensional stress that is directly correlated with the crystalline orientation of the quenched samples. Extensional rheology, particularly, in combination with linear creep measurements, thus, enables the conformational evolution of the UHMw-tail to be studied and linked to the enhanced formation of oriented structures.", "date": "2017-11-21", "date_type": "published", "publication": "ACS Macro Letters", "volume": "6", "number": "11", "publisher": "American Chemical Society", "pagerange": "1268-1273", "id_number": "CaltechAUTHORS:20171101-114633022", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171101-114633022", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Aage og Johanne Louis-Hansen fonden" } ] }, "doi": "10.1021/acsmacrolett.7b00718", "primary_object": { "basename": "mz7b00718_si_001.pdf", "url": "https://authors.library.caltech.edu/records/03p8a-r1p62/files/mz7b00718_si_001.pdf" }, "resource_type": "article", "pub_year": "2017", "author_list": "Wingstrand, Sara L.; Shen, Bo; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/vp53d-0fr14", "eprint_id": 81368, "eprint_status": "archive", "datestamp": "2023-08-19 04:25:56", "lastmod": "2023-10-17 19:47:54", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ford-R", "name": { "family": "Ford", "given": "Rachel" } }, { "id": "Kim-Joey", "name": { "family": "Kim", "given": "Joey" }, "orcid": "0000-0002-3359-4875" }, { "id": "Diallo-M-S", "name": { "family": "Diallo", "given": "Mamadou" }, "orcid": "0000-0002-2571-1568" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia" }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Probing in-situ polymeric particle growth in mixed matrix membranes using ultra-small angle neutron scattering", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society.", "abstract": "Recent advances in the prepn. of mixed matrix membranes with embedded polymeric particles are providing new opportunities to develop the next generation of multifunctional membranes for sustainable chem., engineering, and materials (SusChEM). One such advance combines the durability of polyvinylidene fluoride with the diverse functionality of hydrophilic polymers. Essential to the prepn. of these membranes is the in-situ synthesis of microgel particles in the membrane casting soln. The fouling resistance, stability, and facile functionalization (e.g., metal binding) of these membranes have been well documented; however, understanding the structure-function relationship has proven challenging due to their optical opacity and lack of x-ray scattering contrast. To address this challenge, we developed a new method using ultra-small angle neutron scattering (USANS) to measure microstructure formation in membrane casting solns. Previously, USANS has been limited to equilibrated systems. Here, we use USANS to measure transient structural changes during microgel particle growth. This method will enable not only in-depth structural anal. of membrane casting solns., but also the study of transient microstructure in multicomponent polymer systems in general.", "date": "2017-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20170912-135313235", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170912-135313235", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "collection": "CaltechAUTHORS", "resource_type": "conference_item", "pub_year": "2017", "author_list": "Ford, Rachel; Kim, Joey; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/fy84f-jdp96", "eprint_id": 81396, "eprint_status": "archive", "datestamp": "2023-08-19 04:26:39", "lastmod": "2023-10-17 19:49:11", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Hule-R-A", "name": { "family": "Hule", "given": "Rohan" } }, { "id": "Pirogovsky-P", "name": { "family": "Pirogovsky", "given": "Paul" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia" }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Self-assembly of liquid-crystalline block-copolymers for responsive nematic gels", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society.", "abstract": "Liq. crystals (LCs) are combined with polymers to create soft, rapidly responsive, reversible gels using selfassembly\nof block copolymers having a very long side-group liq.-cryst. polymer (SGLCP) midblock with LCphobic\nendblocks. The unusually high mol.-wt. SGLCP domains used allow gels to form at relatively low concns. that are amenable to alignment by surface anchoring, shear, or magnetic fields. The high content of small-mol.\nliq. crystal (>95%) allows them to reorient quickly. At elevated temps., above the nematic to isotropic\ntransition, the gel dissolves due to the sudden change in solvent quality for the end blocks. To understand the\nreversible self-assembly process, we examine diblock polymers that form responsive micelles rather than\ngels. Small angle neutron scattering (SANS) reveals that the micelles' anisotropic cores have long axes\northogonal to those of the SGLCP corona chains. Flipping the side group orientation from parallel to the\nbackbone (side-on attached mesogens) to perpendicular to the backbone (end-on attachment) flips the anisotropy of both the core and the corona relative to the nematic director. Thus, SANS shows us that the innate orientation of the mesogenic side groups relative to the flexible backbone in the SGLCP block dictates a hierarchy of anisotropy. When the corona chains are SGLCPs having a prolate conformation due to side-on mesogen attachment, the corona mirrors their prolate shape, elongated parallel to the director; in contrast, the micelle core is oblate with its short axis along the director. For SGLCPs that are oblate due to end-on attached mesogens, the corona again has a similar shape and orientation relative to the director. Pairs of polymers with matched LC-phobic blocks have identical size and shape of the core: interfacial tension penalizes prolate cores and dominates over corona crowding in detg. the aggregation no. of the micelle core. Effects of the relative lengths of the coil and SGLCP domains will be described, along with implications for LC physics and technol.", "date": "2017-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20170913-082700658", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170913-082700658", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "collection": "CaltechAUTHORS", "resource_type": "conference_item", "pub_year": "2017", "author_list": "Kurji, Zuleikha; Hule, Rohan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/b4ebh-pb323", "eprint_id": 77229, "eprint_status": "archive", "datestamp": "2023-08-19 02:24:57", "lastmod": "2023-10-25 21:59:49", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhou-Dan", "name": { "family": "Zhou", "given": "Dan" } }, { "id": "Shao-Zixuan", "name": { "family": "Shao", "given": "Zixuan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Exploring the mechanism of action of a newly-discovered therapeutic peptide for blinding retinal diseases by identifying its receptors", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society.", "abstract": "Diabetic and age-related retinopathies, both assocd. with growth of abnormal blood vessels, are leading causes of blindness in the developed world. Current treatments, such as Laser Photocoagulation and anti-Vascular Endothelial Growth Factor (VEGF) drugs, have limited efficacy and undesirable side effects. A recently discovered therapeutic peptide Luminate has proven to be effective in human clin. trials. Over half of the patients in phase I human clin. trial demonstrated vision improvement with 4 lines or over, and in some patients, the macular thicknesses was reduced back to the healthy state. It has shown significantly longer\nlasting benefits than anti-VEGF treatments and shows synergistic effects when used with them. Thus, the\npeptide appears to act through a different pathway than anti-VEGF agents. Finding that pathway may provide\nnew insights into the retinopathies and their managements. Therefore, we are using the peptide as a tool to\nfind the mol. mechanism of its clin. obsd. therapeutic effects. The peptide and its scrambled counterparts\nare used to prep. fluorophore-peptide conjugates and peptide-directed coupling reagents. Results will be\npresented from in-vitro and ex-vivo expts. to visualize the distribution of Luminate binding using fluorophorepeptide\nconjugates. Progress toward enrichment of binding using ligand-directed receptor \"pull down\" will be described. Our goal is to enrich and identify the assocd. receptors by drug-directed crosslinking and immunopercipitation. If successful, identification of the receptor that binds Luminate could provide further insight into the mol. basis of retinopathies, which could guide novel therapeutic agents to prevent vision loss.", "date": "2017-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20170505-130924722", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170505-130924722", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2017", "author_list": "Zhou, Dan; Shao, Zixuan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/k40ec-b8503", "eprint_id": 77117, "eprint_status": "archive", "datestamp": "2023-08-19 02:19:24", "lastmod": "2023-10-25 21:53:34", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lhota-R", "name": { "family": "Lhota", "given": "Red" } }, { "id": "McMullen-R-M", "name": { "family": "McMullen", "given": "Ryan" }, "orcid": "0000-0003-1371-7150" }, { "id": "Huynh-David", "name": { "family": "Huynh", "given": "David" } }, { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "name": { "family": "McKeon", "given": "Beverley" }, "orcid": "0000-0003-4220-1583" } ] }, "title": "Megasupramolecules as molecular probes of turbulence", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society.", "abstract": "Ultralong polymers in dil. soln. have been known since the 1940s to significantly modify turbulent flow, a phenomenon called drag redn., but these long covalent chains suffer from bond scission under stress. As a result of degrdn. and the complexity of turbulence, the mechanism of how long chains impact flow is still not well understood. To imitate ultralong polymers and study the interaction between chains and turbulence, we use long end-associative polymers with hydrogen-bonding end-groups that link in soln. at low concns. to form multi-million mol. wt. supramols. (megasupramols.). These megasupramols. can stretch to\nmicrons in length, while reversibly breaking and reforming in flow conditions, and can be designed to target different length and energy scales in turbulence. Changing the backbone length of the associative units adjusts the reach of the megasupramols., both in the coiled and stretched states. Changing the assocn. strength by choosing alternate functional groups adjusts the stress the megasupramol. will withstand before disassocg. The action of the mols. on the flow is obsd. through particle imaging velocimetry, a technique for detg. detailed velocity profiles and fluctuations, with increased reproducibility due to the ability of the megasupramols. to reversibly associative instead of permanently degrading. Using these megasupramols. as probes explores suppression of different turbulence modes as a route to understand both how drag redn. occurs in polymer solns. and how turbulence can be characterized and manipulated.", "date": "2017-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20170502-080408690", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170502-080408690", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "local_group": { "items": [ { "id": "GALCIT" } ] }, "resource_type": "conference_item", "pub_year": "2017", "author_list": "Lhota, Red; McMullen, Ryan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/2jmg0-v3s73", "eprint_id": 77146, "eprint_status": "archive", "datestamp": "2023-08-19 02:20:50", "lastmod": "2023-10-25 21:55:11", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Earl-C", "name": { "family": "Earl", "given": "Cameron" } }, { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Modular liquid crystal elastomer synthesis: Acid catalyzed oxa-Michael addition", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society.", "abstract": "Incorporating functional groups into liq. crystal elastomer (LCE) networks can help amplify microscopic properties to the macroscopic scale. In 2015, the Yakacki group at the University of Colorado at Denver reported the synthesis of a tailorable and programmable LCE using a two-stage thiol acrylate Michael addn. and photopolymn. This synthesis is highly modular; nearly any diacrylate, and any di- and tetra-thiol can be used to make an elastomer so new functional groups may be introduced to the system by adding new thiol- or acrylate-functionalized monomer to tailor the LCE's properties. Thiols, however, are difficult to synthesize and di- and tetra-functional thiols are hard to find com. Most low mol. wt. thiols also have an extremely low odor threshold (around 0.011 ppm). In contrast, however, terminal alcs. are effectively odorless, more shelf-stable, and available com. in much larger varieties. Taking advantage of the oxa-Michael addn. mechanism, these\nterminal alcs. may provide a viable substitute for the thiol monomers to create a system with even greater\nmodularity. Here we report that through a qual. screening process, triflic and tosyl acid catalysts were found to\nsuccessfully catalyze the polymn. and crosslinking of a model diacrylate with di- and tetra-functional terminal\nalcs. Both traditional heating and microwave radiation were able to activate the reaction. FTIR spectroscopy is being used to first confirm the oxa-Michael reaction, and to monitor reaction kinetics over time.", "date": "2017-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20170503-095921816", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170503-095921816", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2017", "author_list": "Earl, Cameron; Kurji, Zuleikha; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/qqz1t-b1020", "eprint_id": 77159, "eprint_status": "archive", "datestamp": "2023-08-19 02:22:01", "lastmod": "2023-10-25 21:55:58", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Bernhardt-E", "name": { "family": "Bernhardt", "given": "Elizabeth" } }, { "id": "Kuzyk-M-G", "name": { "family": "Kuzyk", "given": "Mark G." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Moldable photo-responsive elastomers from thermoreversible networks formed by triblock copolymer selfassembly", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society.", "abstract": "Photo-responsive soft materials that retain the responsive optical anisotropy of liq. crystals can serve as\nmechano-optic actuators for applications that include non-invasively steering fiber optics for biomedical applications. Here we report that reproducible thermoreversible networks are formed by self-assembly of\ncoil-liq. crystal-coil triblock copolymers: the coil (polystyrene) end-blocks phase segregate from the liq. crystal midblock, forming of uniform and uniformly-spaced phys. crosslinks, These polymers are elastic in the melt\n(at room temp.) and can be easily molded into desired shapes. Starting from identical triblock prepolymers\n(with polystyerene end blocks and 1,2-polybutadiene midblocks), a matched pair (3% azobenzene, and no\nazobenzene) of liq. crystal triblock copolymers was synthesized. These triblocks were then blended to prep. a\nseries of elastomers with 0 to 3% azobenzene groups, while matching in nearly all other phys. properties\n(cross-link d., modulus, birefringence, etc.), and photo-response was quant. measured, allowing us to isolate\nthe effect of concn. of photo-responsive azobenzene groups on photo-response.", "date": "2017-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20170503-125111530", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170503-125111530", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "collection": "CaltechAUTHORS", "resource_type": "conference_item", "pub_year": "2017", "author_list": "Kurji, Zuleikha; Bernhardt, Elizabeth; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dtvda-3z197", "eprint_id": 73362, "eprint_status": "archive", "datestamp": "2023-08-22 19:40:09", "lastmod": "2023-10-24 15:15:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhou-Yuchen", "name": { "family": "Zhou", "given": "Yuchen" } }, { "id": "Huang-Junjie", "name": { "family": "Huang", "given": "Junjie" } }, { "id": "Sun-Wei", "name": { "family": "Sun", "given": "Wei" } }, { "id": "Ju-Yuanlai", "name": { "family": "Ju", "given": "Yuanlai" } }, { "id": "Yang-Pinghui", "name": { "family": "Yang", "given": "Pinghui" } }, { "id": "Ding-Lingyun", "name": { "family": "Ding", "given": "Lingyun" } }, { "id": "Chen-Zhongren", "name": { "family": "Chen", "given": "Zhongren" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Fabrication of Active Surfaces with Metastable Microgel Layers Formed during Breath Figure Templating", "ispublished": "pub", "full_text_status": "public", "keywords": "breath figure method; interfacial assembly of microgels; morphological transitions; responsive patterned polymer surfaces; wettability variations", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: October 24, 2016; Accepted: January 9, 2017; Published: January 9, 2017. \n\nFinancial support from the National Natural Science Foundation of China (No. 21104036), Program for Zhejiang Leading S&T Innovation Team (No. 2011R50001-07), the Natural Science Foundation of Ningbo (No. 2015A610057), Scientific Research Funding of Ningbo University (No. xkl11050, No. xyl14014) and K. C. Wong Magna Fund in Ningbo University is gratefully acknowledged.\n\nSupplemental Material - am6b13525_si_001.pdf
", "abstract": "Patterned porous surfaces with responsive functionalities are fabricated by a thermo-responsive microgel-assisted breath figure (BF) process. When water droplets submerge into a polystyrene (PS) solution during formation of a porous surface by the bottom-up BF process, poly(N-isopropylacrylamide)-co-acrylic acid (PNIPAm-co-AA) microgels dispersed in the solution spontaneously assemble at the water-organic interfaces like \"Pickering emulsions\", reinforced by capillary flow. The conformal layer of PNIPAm-co-AA microgels lining the pores appears in images of scanning electron microscope (SEM) either as a smooth surface layer (L) or as an array of dome-like protrusions (D), depending on the conditions at which the sample was dried for SEM. The change between L and D morphology correlates with the volume phase transition behavior of the microgels freely suspended: drying at a temperature below the Volume Phase Transition Temperature (VPTT) gives L, and the D morphology is formed by drying at a temperature greater than the VPTT of PNIPAm-co-AA microgels. The morphological transition is shown to accompany a significant change in surface contact angle (CA) relative to a corresponding pore layer made of PS, with L having a CA that is reduced by 85\u00b0 relative to PS, while the decrease is only 22\u00b0 for D. Porous structures with morphologically responsive surfaces could find application in biocatalysis or tissue engineering, for example, with functional enzymes sequestered when microgels are collaped and accessible when the microgels are swollen.", "date": "2017-02-01", "date_type": "published", "publication": "ACS Applied Materials & Interfaces", "volume": "9", "number": "4", "publisher": "American Chemical Society", "pagerange": "4177-4183", "id_number": "CaltechAUTHORS:20170110-094112417", "issn": "1944-8244", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170110-094112417", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21104036" }, { "agency": "Program for Zhejiang Leading S&T Innovation Team", "grant_number": "2011R50001-07" }, { "agency": "Natural Science Foundation of Ningbo", "grant_number": "2015A610057" }, { "agency": "Ningbo University", "grant_number": "xkl11050" }, { "agency": "Ningbo University", "grant_number": "xyl14014" } ] }, "doi": "10.1021/acsami.6b13525", "primary_object": { "basename": "am6b13525_si_001.pdf", "url": "https://authors.library.caltech.edu/records/dtvda-3z197/files/am6b13525_si_001.pdf" }, "resource_type": "article", "pub_year": "2017", "author_list": "Zhou, Yuchen; Huang, Junjie; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/56rte-vm112", "eprint_id": 88146, "eprint_status": "archive", "datestamp": "2023-08-18 23:57:44", "lastmod": "2024-01-14 20:29:28", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kuzyk-M-G", "name": { "family": "Kuzyk", "given": "Mark G." } } ] }, "title": "Photo-responsive and thermoreversible networks from the self-assembly of azobenzene-containing liquid crystal triblock copolymers", "ispublished": "unpub", "full_text_status": "public", "note": "\u00a9 2016 Society of Photo-optical Instrumentation Engineers (SPIE).", "abstract": "We report the synthesis of azobenzene-containing coil-liquid crystal-coil triblock copolymers that can serve as mechano-optic actuators for applications that include non-invasively steering fiber optics. The coil (polystyrene) end-blocks phase segregate from the liquid crystal midblock forming of uniform and uniformly-spaced physical crosslinks, resulting in highly reproducible and thermoreversible networks by self-assembly. These polymers are elastic in the melt (at room temperature) and can be easily spun, coated or molded. Mechanical stretching results in a temporary monodomain alignment. Starting from identical triblock prepolymers (with polystyerene end blocks and 1,2-polybutadiene midblocks), a matched pair (azobenzene-containing, and non-azobenzene-containing) of liquid crystal triblock copolymers was synthesized. These triblocks were then be blended to prepare a series of elastomers with 0 to 5% azobenzene groups, while matching in nearly all other physical properties (cross-link density, modulus, birefringence, etc.), allowing the effect of concentration of photo-responsive groups to be unambiguously determined. Results will be presented that demonstrate this approach to independent control of optical density and photo-mechanical sensitivity.", "date": "2016-11-03", "date_type": "published", "publisher": "Society of Photo-optical Instrumentation Engineers (SPIE)", "place_of_pub": "Bellingham, WA", "pagerange": "Art. No. 99390B", "id_number": "CaltechAUTHORS:20180723-155342466", "isbn": "9781510602694", "book_title": "Light Manipulating Organic Materials and Devices III", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180723-155342466", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Haley-J-E", "name": { "family": "Haley", "given": "Joy E." } }, { "id": "Schuller-J-A", "name": { "family": "Schuller", "given": "Jon A." } }, { "id": "Eich-M", "name": { "family": "Eich", "given": "Manfred" } }, { "id": "Nunzi-J-M", "name": { "family": "Nunzi", "given": "Jean-Michel" } } ] }, "doi": "10.1117/12.2238494", "resource_type": "book_section", "pub_year": "2016", "author_list": "Kurji, Zuleikha; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/nnr05-k2k67", "eprint_id": 70635, "eprint_status": "archive", "datestamp": "2023-08-22 18:54:46", "lastmod": "2023-10-20 23:17:07", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ailianou-Artemis", "name": { "family": "Ailianou", "given": "Artemis" } }, { "id": "Ramachandran-Karthik", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Kossuth-Mary-Beth", "name": { "family": "Kossuth", "given": "Mary Beth" } }, { "id": "Oberhauser-James-Paul", "name": { "family": "Oberhauser", "given": "James Paul" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Multiplicity of morphologies in poly (L-lactide) bioresorbable vascular scaffolds", "ispublished": "pub", "full_text_status": "public", "keywords": "structural transformation; ductility; poly (L-lactide); coronary heart disease; microdiffraction", "note": "\u00a9 2016 National Academy of Sciences. \n\nEdited by John A. Rogers, University of Illinois, Urbana, IL, and approved August 12, 2016 (received for review April 22, 2016) \n\nThis research used resources of the Advanced Photon Source (APS), a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357. We thank Dr. Zhonghou Cai at APS for his assistance in collecting x-ray microdiffraction data, and Mr. Troy P. Carter (Abbott Vascular) for sectioning the scaffolds. We appreciate the assistance of Dr. Nobumichi Tamura at the Advanced Light Source, Lawrence Berkeley National Laboratories, for proof-of-concept x-ray microdiffraction measurements. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under Contract DE-AC02-05CH1123. Funding for this research was provided by Abbot Vascular. \n\nA.A and K.R contributed equally to this work. \n\nAuthor contributions: A.A., K.R., and J.A.K. designed research; A.A. and K.R. performed research; M.B.K., J.P.O., and J.A.K. contributed new reagents/analytic tools; A.A., K.R., and J.A.K. analyzed data; and A.A., K.R., and J.A.K. wrote the paper. \n\nConflict of interest statement: M.B.K. and J.P.O. are employees of Abbott Vascular. Funding for this research was provided by Abbott Vascular. \n\nThis article is a PNAS Direct Submission. \n\nThis article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1602311113/-/DCSupplemental.\n\nPublished - PNAS-2016-Ailianou-11670-5.pdf
Supplemental Material - pnas.201602311SI.pdf
", "abstract": "Poly(L-lactide) (PLLA) is the structural material of the first clinically approved bioresorbable vascular scaffold (BVS), a promising alternative to permanent metal stents for treatment of coronary heart disease. BVSs are transient implants that support the occluded artery for 6 mo and are completely resorbed in 2 y. Clinical trials of BVSs report restoration of arterial vasomotion and elimination of serious complications such as late stent thrombosis. It is remarkable that a scaffold made from PLLA, known as a brittle polymer, does not fracture when crimped onto a balloon catheter or during deployment in the artery. We used X-ray microdiffraction to discover how PLLA acquired ductile character and found that the crimping process creates localized regions of extreme anisotropy; PLLA chains in the scaffold change orientation from the hoop direction to the radial direction on micrometer-scale distances. This multiplicity of morphologies in the crimped scaffold works in tandem to enable a low-stress response during deployment, which avoids fracture of the PLLA hoops and leaves them with the strength needed to support the artery. Thus, the transformations of the semicrystalline PLLA microstructure during crimping explain the unexpected strength and ductility of the current BVS and point the way to thinner resorbable scaffolds in the future.", "date": "2016-10-18", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "113", "number": "42", "publisher": "National Academy of Sciences", "pagerange": "11670-11675", "id_number": "CaltechAUTHORS:20160928-105122973", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160928-105122973", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-06CH11357" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH1123" }, { "agency": "Abbot Vascular" } ] }, "doi": "10.1073/pnas.1602311113", "pmcid": "PMC5081625", "primary_object": { "basename": "pnas.201602311SI.pdf", "url": "https://authors.library.caltech.edu/records/nnr05-k2k67/files/pnas.201602311SI.pdf" }, "related_objects": [ { "basename": "PNAS-2016-Ailianou-11670-5.pdf", "url": "https://authors.library.caltech.edu/records/nnr05-k2k67/files/PNAS-2016-Ailianou-11670-5.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Ailianou, Artemis; Ramachandran, Karthik; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/cj67z-pzh10", "eprint_id": 75474, "eprint_status": "archive", "datestamp": "2023-08-20 13:39:41", "lastmod": "2023-10-25 15:04:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kuppermann-B-D", "name": { "family": "Kuppermann", "given": "Baruch D." } }, { "id": "Boyer-D-S", "name": { "family": "Boyer", "given": "David S." } }, { "id": "Kaiser-P-K", "name": { "family": "Kaiser", "given": "Peter K." } }, { "id": "Heier-J-S", "name": { "family": "Heier", "given": "Jeffrey S." } }, { "id": "Campochiaro-P-A", "name": { "family": "Campochiaro", "given": "Peter A." } }, { "id": "Quiroz-Mercado-H", "name": { "family": "Quiroz-Mercado", "given": "Hugo" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia" }, "orcid": "0000-0001-6746-8634" }, { "id": "Karageozian-L", "name": { "family": "Karageozian", "given": "Lisa" } }, { "id": "Genead-M-A", "name": { "family": "Genead", "given": "Mohamed A." } }, { "id": "Karageozian-H-L", "name": { "family": "Karageozian", "given": "Hampar L." } }, { "id": "Karageozian-V-H", "name": { "family": "Karageozian", "given": "Vicken H." } } ] }, "title": "Topline Results From Prospective, Double-masked, Placebo Controlled Phase 2 Clinical Study Evaluating Luminate\u00ae (ALG-1001) in Patients with Symptomatic Focal Vitreomacular Adhesion", "ispublished": "pub", "full_text_status": "public", "note": "These abstracts are licensed under a Creative Commons Attribution-NonCommercial-No Derivatives 4.0 International License. Go to http://iovs.arvojournals.org/ to access the versions of record.\n\nPublished - Kuppermann_2016p1809.pdf
", "abstract": "Purpose : To investigate the safety and efficacy of Luminate (ALG-1001), a synthetic anti-angiogenic and vitreolytic oligopeptide, administered intravitreally in patients with focal vitreomacular adhesion (VMA) or vitreomacular traction (VMT).", "date": "2016-09", "date_type": "published", "publication": "Investigative Ophthalmology and Visual Science", "volume": "57", "number": "12", "publisher": "Association for Research in Vision and Ophthalmology", "pagerange": "Art. No. 1809", "id_number": "CaltechAUTHORS:20170328-105955940", "issn": "1552-5783", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170328-105955940", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "primary_object": { "basename": "Kuppermann_2016p1809.pdf", "url": "https://authors.library.caltech.edu/records/cj67z-pzh10/files/Kuppermann_2016p1809.pdf" }, "resource_type": "article", "pub_year": "2016", "author_list": "Kuppermann, Baruch D.; Boyer, David S.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dh56r-r2r81", "eprint_id": 70316, "eprint_status": "archive", "datestamp": "2023-08-20 13:08:06", "lastmod": "2023-10-20 22:09:24", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kim-Joey", "name": { "family": "Kim", "given": "Joey" }, "orcid": "0000-0002-3359-4875" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Conformation of the backbone of bottlebrush polymers", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2016 American Chemical Society.", "abstract": "Bottlebrush polymers are a hierarchal arrangement of linear polymer chains into two domains: the side chain domain\n(which disfavors crowding) densely grafted onto a backbone domain (which resists stretching). The net result of the\ninteractions between the two domains is a relatively expanded conformation of the backbone. Despite numerous theor.,\nsimulation and exptl. approaches, there is still controversy on the soln. behavior of bottlebrush polymers. Exptl., a main\nproblem can be attributed to limitations that result from the complex architecture; isolating the behavior of each domain is\nvery difficult. Therefore, exptl. detn. on each domain thus far has only been inferred from the overall structure as\nopposed to being directly measured. Using small-angle neutron scattering (SANS) and selective deuterium labeling, we\nobtained exptl. conformation of the backbone domain alone. To our knowledge, we are the first to obtain these results.\nThe current accepted model in literature was developed by Birshtein et al. in 1985, which is a self-avoiding walk of 'super'\nblobs. Our SANS results build on to this exceptional model and provides addnl. insight that has not yet been discussed\nin literature in the bottlebrush context.", "date": "2016-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20160913-124545450", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160913-124545450", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2016", "author_list": "Kim, Joey and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ncmge-5r666", "eprint_id": 70391, "eprint_status": "archive", "datestamp": "2023-08-20 13:09:06", "lastmod": "2023-10-20 22:54:47", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kim-Joey", "name": { "family": "Kim", "given": "Joey" }, "orcid": "0000-0002-3359-4875" }, { "id": "Hadjichristidis-N", "name": { "family": "Hadjichristidis", "given": "Nikos" }, "orcid": "0000-0003-1442-1714" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Crystallization-driven ordering and self-assembly in bottlebrush polymers", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2016 American Chemical Society.", "abstract": "The natural building blocks of linear polymer are monomers. Similarly, the natural building blocks of bottblebrush\npolymers are linear polymers (commonly referred to as polymacromonomers). It is well established that many properties\nof linear polymers can be tuned by using different copolymer systems. Similarly, we expect tunability of bottlebrush\npolymers by using chem. distinct polymer chains. A collaborative effort with Hadjichristidis from KAUST led us to a\ndeeper study on the arrangement of chem. distinct polymeric units within the bottlebrush architecture. We have\norganized these samples into four categories based on the geometric connectivity: homo-bottlebrush polymer (H) in\nwhich all side chains have identical chem. functionality, main chain block bottlebrush polymers (M) which has chem.\ndistinct side chains are grafted in groups along the backbone, random-co-bottlebrush (R) in which the sequence of\ngrafting is detd. by the no. fraction of each chem. distinct side chain, and diblock side chains bottlebrush polymer (D) in\nwhich the side chains themselves are block copolymers. Three chem. distinct polymers were chosen as side chains to\nexplore the effects of chem. functionality as well as the crystn. on behavioral properties: polyethylene (E),\npolycaprolactone (C), and atactic-polystyrene (S). The former two are known to be semicryst. In the melt phase we\nused differential scanning calorimeter (DSC) and in soln., we used small-angle neutron scattering (SANS). Our results\nindicate connectivity has a large impact on the behavior of bottlebrush polymers.", "date": "2016-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20160916-092708085", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160916-092708085", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2016", "author_list": "Kim, Joey; Hadjichristidis, Nikos; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6ghgd-gtv73", "eprint_id": 65960, "eprint_status": "archive", "datestamp": "2023-08-20 10:36:03", "lastmod": "2023-10-18 17:00:04", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Interplay of macromolecular architecture and flow in polymer crystallization", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2016 American Chemical Society.", "abstract": "Processing flow can accelerate crystn. by orders of magnitude compared to the quiescent case, allowing lowcost,\nhigh-vol. manufg. Flow can also induce highly oriented crystal morphologies that allow simple polymers\nto attain exceptional properties. Among synthetic polymers, semicryst. polyolefins are the dominant materials\ndue to their vast importance to quality of life worldwide. The architecture of the longest, slowest relaxing\nchains profoundly affects the kinetics and morphol. of flow-induced nuclei; and the \"long chains\" can exert\nstrong effects even at low concn. This talk focuses on the importance of long-chain branching. We have\nexamd. model binary blends of well-defined, H-polymer chains at low concns. in a matrix of entangled\npolyethylene chains. A new class of model branched polyethylenes is synthesized having H architecture with a\n\"strut\" that is free of short chain branching and \"arms\" that have a few percent short chain branching.\nTransient measurements of flow-induced crystn. in these binary blends reveal the effects of precisely tailored\nH-shaped polyethylenes on the nucleation and growth of polymer crystals.", "date": "2016-03", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20160406-095202682", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160406-095202682", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2016", "author_list": "Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7dy8d-vmh31", "eprint_id": 65894, "eprint_status": "archive", "datestamp": "2023-08-20 10:35:28", "lastmod": "2023-10-18 16:54:30", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ramachandran-K", "name": { "family": "Ramachandran", "given": "Karthik" }, "orcid": "0000-0003-1820-7555" }, { "id": "Ailianou-A", "name": { "family": "Ailianou", "given": "Artemis" } }, { "id": "Kossuth-M-B", "name": { "family": "Kossuth", "given": "Mary Beth" } }, { "id": "Oberhauser-J-P", "name": { "family": "Oberhauser", "given": "James" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Morphological variations in poly (L-Lactic Acid) (PLLA) vascular scaffolds for the treatment of coronary heart disease (CHD)", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2016 American Chemical Society.", "abstract": "Poly (L-lactic Acid) (PLLA) is a semicryst. and biocompatible polymer that is used in bioresorbable vascular\nscaffolds for the treatment of Coronary Heart Disease (CHD). To treat CHD, a PLLA scaffold is deployed in the\noccluded artery to restore blood circulation. Implants made of PLLA undergo hydrolysis to form L-lactic acid that\nis readily metabolized by the human body, allowing them to harmlessly disappear in two years. The polymer is\nsubjected to tube expansion and laser cutting before it is crimped onto a balloon. When the crimped scaffold is\nin position in the diseased artery, the balloon is inflated to deploy the scaffold. The resulting semicryst.\nstructure changes over distances of a few microns, requiring X-ray microdiffraction to shed light on the\nstructural changes that occur in PLLA vascular scaffolds which govern their therapeutic function. Crimping\nplaces the outer bend (OB) of a U-crest under elongation and the inner bend (IB) under compression. X-ray\ndiffraction patterns indicate highly oriented PLLA crystallites where elongation was imposed (near the OB) and\ncrystallites tilted out of plane where compression was imposed (at the IB). Between the IB and the OB, there is\nan unperturbed region with an orientation similar to the expanded tube. Deployment profoundly alters the\nstructure created during crimping. The tilting of crystallites at the IB during crimping allows them to gracefully\nsep. into diamond shaped voids when the IB is placed under tension during deployment. Consequently, the OB\nexperiences relatively mild compressive stress during deployment and a highly uniform structure is obsd.\nDespite PLLA's reputation as a brittle plastic, the solid state deformation does not fracture the scaffold; rather,\nthe deployed PLLA scaffold has a high degree of orientation, giving the scaffold the radial strength to hold the\nblood vessel open.", "date": "2016-03", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20160404-131359139", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160404-131359139", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2016", "author_list": "Ramachandran, Karthik; Ailianou, Artemis; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/3v5cp-es551", "eprint_id": 63332, "eprint_status": "archive", "datestamp": "2023-08-20 08:34:20", "lastmod": "2024-01-13 16:30:46", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kuzyk-M-G", "name": { "family": "Kuzyk", "given": "Mark G." } } ] }, "title": "Model photo-responsive elastomers based on the self-assembly of side group liquid crystal triblock copolymers (Presentation Recording)", "ispublished": "unpub", "full_text_status": "public", "note": "\u00a9 2015 SPIE.\n\nPublished - 95640I.pdf
", "abstract": "We report the synthesis of azobenzene-containing coil-liquid crystal-coil triblock copolymers that form uniform and highly reproducible elastomers by self-assembly. To serve as actuators to (non-invasively) steer a fiber optic, for example in deep brain stimulation, the polymers are designed to become monodomain \"single liquid crystal\" elastomers during the fiber-draw process and to have a large stress/strain response to stimulation with either light or heat. A fundamental scientific question that we seek to answer is how the interplay between the concentration of photoresponsive mesogens and the proximity to the nematic-isotropic transition governs the sensitivity of the material to stimuli. Specifically, a matched pair of polymers, one with ~5% azobenzene-containing side groups (~95% cyanobiphenyl side groups) and the other with 100% cyanobiphenyl side groups were synthesized from identical triblock pre-polymers (with polystyerene end blocks and 1,2-polybutadiene midblocks). These can be blended in various ratios to prepare a series of elastomers that are precisely matched in terms of the backbone length between physical crosslinks (because each polymer is derived from the same pre-polymer), while differing in % azobenzene side groups, allowing the effect of concentration of photoresponsive groups to be unambiguously determined.", "date": "2015-10-05", "date_type": "published", "publisher": "Society of Photo-Optical Instrumentation Engineers", "place_of_pub": "Bellingham, WA", "pagerange": "Art. No. 95640I", "id_number": "CaltechAUTHORS:20160104-130309600", "isbn": "978-1-62841-730-2", "book_title": "Light Manipulating Organic Materials and Devices II", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160104-130309600", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Schuller-J-A", "name": { "family": "Schuller", "given": "Jon A." } } ] }, "doi": "10.1006/jcis.1997.537910.1117/12.2186347", "primary_object": { "basename": "95640I.pdf", "url": "https://authors.library.caltech.edu/records/3v5cp-es551/files/95640I.pdf" }, "resource_type": "book_section", "pub_year": "2015", "author_list": "Kurji, Zuleikha; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/x8e3w-v6735", "eprint_id": 63328, "eprint_status": "archive", "datestamp": "2023-08-20 08:34:16", "lastmod": "2024-01-13 16:30:44", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } } ] }, "title": "Thermoreversible networks for moldable photo-responsive elastomers (Presentation Recording)", "ispublished": "unpub", "full_text_status": "public", "note": "\u00a9 2015 SPIE. Date Published: 5 October 2015. \n\nView presentation video on SPIE's Digital Library: http://dx.doi.org/10.1117/12.2187717.4519371758001\n\nPublished - 95640H.pdf
", "abstract": "Soft-solids that retain the responsive optical anisotropy of liquid crystals (LC) can be used as mechano-optical, electro-optical and electro-mechanical elements. We use self-assembly of block copolymers to create reversible LC gels and elastomers that flow at elevated temperatures and physically cross link upon cooling. In the melt, they can be spun, coated or molded. Segregation of the end-blocks forms uniform and uniformly spaced crosslinks. Matched sets of block copolymers are synthesized from a single \"prepolymer.\" Specifically, we begin with polymers having polystyrene (PS) end blocks and a poly(1,2-butadiene) midblock. The pendant vinyl groups along the backbone of the midblock are used to graft mesogens, converting it to a side-group LC polymer (SGLCP). In the present case, cyanobiphenyl groups are used as the nonphotoresponsive mesogens and azobenzene groups are used as photoresponsive mesogens. Here we show that matched pairs of block copolymers, with and without photo-responsive mesogens, provide model systems in which the optical density can be adjusted while holding other properties fixed (cross-link density, modulus, birefringence, isotropic-nematic transition temperature). For example, a triblock in which the SGLCP block has 95% cyanobiphenyl and 5% azo side groups is miscible with one having 100% cyanobiphenyl side groups. Simply blending the two gives a series of LC elastomers that have from 0 to 5% azo, while having all other physical properties matched. Results will be presented that show the outcomesof this approach to systematic and largely independent control of optical density and photo-mechanical sensitivity.", "date": "2015-10-05", "date_type": "published", "publisher": "Society of Photo-Optical Instrumentation Engineers", "place_of_pub": "Bellingham, WA", "pagerange": "Art. No. 95640H", "id_number": "CaltechAUTHORS:20160104-114138928", "isbn": "978-1-62841-730-2", "book_title": "Light Manipulating Organic Materials and Devices II", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160104-114138928", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Schuller-J-A", "name": { "family": "Schuller", "given": "Jon A." } } ] }, "doi": "10.1117/12.2187717", "primary_object": { "basename": "95640H.pdf", "url": "https://authors.library.caltech.edu/records/x8e3w-v6735/files/95640H.pdf" }, "resource_type": "book_section", "pub_year": "2015", "author_list": "Kornfield, Julia A. and Kurji, Zuleikha" }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/nwaa5-ran48", "eprint_id": 60693, "eprint_status": "archive", "datestamp": "2023-08-20 08:32:52", "lastmod": "2023-10-24 21:06:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } }, { "id": "Li-Boyu", "name": { "family": "Li", "given": "Boyu" } }, { "id": "David-R-L-A", "name": { "family": "David", "given": "R. L.Ameri" } }, { "id": "Jones-S-C", "name": { "family": "Jones", "given": "Simon C." }, "orcid": "0000-0002-1952-3720" }, { "id": "Saohia-V", "name": { "family": "Sarohia", "given": "Virendra" } }, { "id": "Schmitigal-J-A", "name": { "family": "Schmitigal", "given": "Joel A." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Megasupramolecules for safer, cleaner fuel by end association of long telechelic polymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Association for the Advancement of Science. \n\nReceived for publication 30 March 2015. Accepted for publication 30 July 2015. \n\nFunding for this research was provided from U.S. Army TARDEC, FAA, and NASA (NAS7-03001) and the Gates Grubstake Fund. B.L. is grateful for support from the Schlumberger Foundation Faculty for the Future Program. We thank P. Arakelian (GALCIT) and T. Wynne (JPL) for assistance with the fuel impact tests; B. Hammouda (NIST) and L. He (ORNL) for assistance with SANS; T. Durbin, R. Russell, D. Pacocha, and K. Bumiller at UCR CE-CERT for assistance with engine tests; A. Meyer at Wyatt Technology and Caltech graduate student J. Kim for assistance with MALLS; and Caltech undergraduates S. Li and A. Guo for assistance with shear degradation tests and rheological measurements. A patent application (WO/2014/145920) based on some results reported here has been submitted.\n\nSupplemental Material - Wei.SM.pdf
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", "abstract": "We used statistical mechanics to design polymers that defy conventional wisdom by self-assembling into \"megasupramolecules\" (\u22655000 kg/mol) at low concentration (\u22640.3 weight percent). Theoretical treatment of the distribution of individual subunits\u2014end-functional polymers\u2014among cyclic and linear supramolecules (ring-chain equilibrium) predicts that megasupramolecules can form at low total polymer concentration if, and only if, the backbones are long (>400 kg/mol) and end-association strength is optimal. Viscometry and scattering measurements of long telechelic polymers having polycyclooctadiene backbones and acid or amine end groups verify the formation of megasupramolecules. They control misting and reduce drag in the same manner as ultralong covalent polymers. With individual building blocks short enough to avoid hydrodynamic chain scission (weight-average molecular weights of 400 to 1000 kg/mol) and reversible linkages that protect covalent bonds, these megasupramolecules overcome the obstacles of shear degradation and engine incompatibility.", "date": "2015-10-02", "date_type": "published", "publication": "Science", "volume": "350", "number": "6256", "publisher": "American Association for the Advancement of Science", "pagerange": "72-75", "id_number": "CaltechAUTHORS:20151001-124940671", "issn": "0036-8075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151001-124940671", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC)" }, { "agency": "Federal Aviation Administration (FAA)" }, { "agency": "NASA", "grant_number": "NAS7-03001" }, { "agency": "Gates Grubstake Fund" }, { "agency": "Schlumberger Foundation" } ] }, "doi": "10.1126/science.aab0642", "primary_object": { "basename": "Wei.SM.pdf", "url": "https://authors.library.caltech.edu/records/nwaa5-ran48/files/Wei.SM.pdf" }, "related_objects": [ { "basename": "aab0642s1.mov", "url": "https://authors.library.caltech.edu/records/nwaa5-ran48/files/aab0642s1.mov" }, { "basename": "aab0642s2.mov", "url": "https://authors.library.caltech.edu/records/nwaa5-ran48/files/aab0642s2.mov" }, { "basename": "aab0642s3.mov", "url": "https://authors.library.caltech.edu/records/nwaa5-ran48/files/aab0642s3.mov" }, { "basename": "aab0642s4.mov", "url": "https://authors.library.caltech.edu/records/nwaa5-ran48/files/aab0642s4.mov" }, { "basename": "aab0642s5.mov", "url": "https://authors.library.caltech.edu/records/nwaa5-ran48/files/aab0642s5.mov" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Wei, Ming-Hsin; Li, Boyu; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dv9vf-ff279", "eprint_id": 60343, "eprint_status": "archive", "datestamp": "2023-08-20 07:52:52", "lastmod": "2023-10-24 16:27:18", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Yanfei", "name": { "family": "Li", "given": "Yanfei" } }, { "id": "Hsiao-Kai-Wen", "name": { "family": "Hsiao", "given": "Kai-Wen" } }, { "id": "Brockman-C-A", "name": { "family": "Brockman", "given": "Christopher A." } }, { "id": "Yates-D-Y", "name": { "family": "Yates", "given": "Daniel Y." } }, { "id": "Robertson-Anderson-R-M", "name": { "family": "Robertson-Anderson", "given": "Rae M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "San-Francisco-M-J", "name": { "family": "San Francisco", "given": "Michael J." } }, { "id": "Schroeder-C-M", "name": { "family": "Schroeder", "given": "Charles M." } }, { "id": "McKenna-G-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" } ] }, "title": "When Ends Meet: Circular DNA Stretches Differently in Elongational Flows", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2015 American Chemical Society.\n\nReceived: June 23, 2015; Revised: July 25, 2015; Published: August 7, 2015. \n\nThe work at TTU Chemical Engineering was supported by the John R. Bradford Endowment and the Paul Whitfield Horn Professorship. The work at UIUC was funded by a Dow Graduate Fellowship for K.-W.H. and C.A.B., and the David and Lucile Packard Foundation, NSF CAREER Award CBET-1254340, and the Camille and Henry Dreyfus Foundation for C.M.S. R.M.R.-A. was funded by the AFOSR Young Investigator Program, Grant No. FA95550-12-1-0315. \n\nThe authors declare no competing financial interest.", "abstract": "Chain topology has a profound impact on the flow behavior of single macromolecules. For circular polymers, the absence of free ends results in a unique chain architecture compared to linear or branched chains, thereby generating distinct molecular dynamics. Here, we report the direct observation of circular DNA dynamics in transient and steady flows for molecular sizes spanning the range of 25.0\u2013114.8 kilobase pairs (kbp). Our results show that the longest relaxation times of the rings follow a power-law scaling relation with molecular weight that differs from that of linear chains. Also, relative to their linear counterparts, circular DNA molecules show a shifted coil-to-stretch transition and less diverse \"molecular individualism\" behavior as evidenced by their conformational stretching pathways. These results show the impact of chain topology on dynamics and reveal commonalities in the steady state behavior of circular and linear DNA that extends beyond chain architecture.", "date": "2015-08-25", "date_type": "published", "publication": "Macromolecules", "volume": "48", "number": "16", "publisher": "American Chemical Society", "pagerange": "5997-6001", "id_number": "CaltechAUTHORS:20150918-143504780", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150918-143504780", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "John R. Bradford Endowment" }, { "agency": "Paul Whitfield Horn Professorship" }, { "agency": "Dow Graduate Fellowship" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "NSF", "grant_number": "CBET-1254340" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "FA95550-12-1-0315" } ] }, "doi": "10.1021/acs.macromol.5b01374", "resource_type": "article", "pub_year": "2015", "author_list": "Li, Yanfei; Hsiao, Kai-Wen; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/g3kqb-ms706", "eprint_id": 60031, "eprint_status": "archive", "datestamp": "2023-08-20 07:30:42", "lastmod": "2023-10-24 14:49:43", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Seeing clearly: Using protein nanofibers to promote orderly corneal wound healing", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2015 American Chemical Society.", "abstract": "The study evaluates the ability of electrospun protein nanofibers to display topog. and biochem. cues to\nsupport epithelial closure, foster fibroblast recruitment and mitigate myofibroblast phenotype. Gelatin\nelectrospun nanofibers were used to present integrin binding sites and mech. cues. By control of the\nelectrode geometry, we prep. nanofiber mats with three types of orientation: isotropic, radial, and uniaxial.\nRates of epithelial and fibroblast cell migration in vitro, measured using a mock wound healing assay,\nshowed a result for epithelial cells. While fibroblasts (and a variety of cells in the literature) migrate rapidly on\noriented nanofibers, corneal epithelial cells migrate faster on isotropic nanofibers than on aligned\nnanofibers or planar controls. Of particular importance, prodn. of smooth muscle actin (\u03b1SMA, green in\nimage) by myofibroblasts (TGF-\u03b2 transformed fibroblasts) was reduced in cells cultured on oriented nanofiber\nsubstrates. Nanofiber diam. over the range 100-220 nm does not measurably affect migration or \u03b1SMA\nexpression. The mol. mechanism by which myofibroblasts respond to topog. cues was explored using siRNA\ntransfected cells with knockdown of kinases assocd. with integrin mediated response (FAK and Raf-1) and\ntranscriptional regulators assocd. with mechanotransduction (YAP and TAZ). We were surprised that the\nresponse does not involve integrin-mediated transduction; it involves YAP and TAZ (indicative of\nmechanostranduction). Preliminary in vivo expts. in mice and rabbits showed reepithelialization occurs as\nquickly over nanofiber scaffolds as it does over the native corneal stroma. The population of inflammatory\ncells was reduced in wound beds treated with nanofiber scaffolds relative to untreated controls. Oriented\nnanofiber scaffolds do not elicit an inflammatory response and have an anti-inflammatory effect. Oriented\nnanofiber substrates are well suited for corneal wound applications due to their transparency, non-cytotoxicity\nand ability to modulate the myofibroblast phenotype.", "date": "2015-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20150902-105126759", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150902-105126759", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2015", "author_list": "Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/rtw32-kx436", "eprint_id": 58199, "eprint_status": "archive", "datestamp": "2023-08-22 15:52:40", "lastmod": "2023-10-23 19:09:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hu-Miao", "name": { "family": "Hu", "given": "Miao" } }, { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "Daeffler-C-S", "name": { "family": "Daeffler", "given": "Christopher S." } }, { "id": "Wang-Jinhua", "name": { "family": "Wang", "given": "Jinhua" } }, { "id": "McKenna-G-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "The linear rheological responses of wedge-type polymers", "ispublished": "pub", "full_text_status": "restricted", "keywords": "branched; glassy polymers; macromonomers; rheology; viscoelastic properties; viscosity", "note": "\u00a9 2015 Wiley Periodicals, Inc.\n\nReceived 2 November 2014; Revised 18 February 2015; Accepted 1 March 2015; Published online 27 March 2015.\n\nThis research was supported primarily by the U.S. Department\nof Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-\n05ER46218. Partial support was also provided the National Science Foundation under grant DMR-1207070 and by the John R. Bradford Endowment at Texas Tech University.", "abstract": "The linear rheological responses of a series of specially designed wedge-type polymers synthesized by the polymerization of large molecular weight monomers have been measured. These wedge polymers contained large side groups which contained three flexible branch chains per polymer chain unit. The master curves for these polymers were obtained by time temperature superposition of dynamic data at different temperatures from the terminal flow regime to well below the glass transition temperature, T_g. While these polymers maintained a behavior similar to that of linear polymers, the influence of the large side group structure lead to low entanglement densities and extremely low rubbery plateau modulus values, being near to 13 kPa. The viscosity molecular weight dependence was also somewhat higher than that normally observed for linear polymers, tending toward a power law near to 4.2 rather than the typical 3.4 found in entangled linear chains. The glassy modulus of these branched polymers is also found to be extremely low, being less than 100 MPa at T_g \u221260 \u00b0C.", "date": "2015-07-01", "date_type": "published", "publication": "Journal of Polymer Science, Part B: Polymer Physics", "volume": "53", "number": "13", "publisher": "John Wiley & Sons, Inc.", "pagerange": "899-906", "id_number": "CaltechAUTHORS:20150611-124509841", "issn": "0887-6266", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150611-124509841", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-05ER46218" }, { "agency": "NSF", "grant_number": "DMR-1207070" }, { "agency": "Texas Tech University John R. Bradford Endowment" } ] }, "doi": "10.1002/polb.23716", "resource_type": "article", "pub_year": "2015", "author_list": "Hu, Miao; Xia, Yan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/tedtn-xdd52", "eprint_id": 56434, "eprint_status": "archive", "datestamp": "2023-08-20 05:06:38", "lastmod": "2023-10-23 15:24:21", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Mega-supramolecules for energy conservation and fire safety using long end-associative telechelics in fuel", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2015 American Chemical Society.", "abstract": "Liq. fuels (petroleum, diesel, kerosene, etc.) are the world's dominant power source (34\u0302 of global energy\nconsumption, 32.5 Billion barrels in 2011). Transportation relies on liq. fuels, presenting the risk of explosive\ncombustion in the event of impact. Ultra-long linear polymers offer the benefits of reduced risk of post-crash\nfires and reduced energy consumption used to transport fuel across the US. Problems with shear degrdn. and\nincompatibility with engine operation caused them to be largely abandoned since 1984. Here we provide an\n\"existence proof\" for supramols. that are so long that they confer the benefits of ultra-long covalent polymers\n(e.g., >4M g/mol polyisobutylene), without their deficiencies. Based on the statistical mechanics of ringchain\nequil., to form \"mega-supramols.\" at low concn., very long building blocks are designed. Adopting the\nHilmyer-Macosco protocol for ROMP of cyclooctadiene with CTAs bearing end-groups, improvements in\nmonomer purifn. enabled synthesis of telechelics with unprecedented length (telechelic polymers with\nMw>400 kg/mol). Simple carboxylic acid - tertiary amine pairs are designed to provide complementary endassocn.\nthat is amenable to scale up; surprisingly, they also proved to be more effective than such multidentate\n\"stickers\" as Hamilton receptor and cyanuric acid. Steady shear viscometry confirmed the dramatic\nenhancement in the rheol. effect brought by longer backbone length. GPC-MALLS and SANS were performed to\nstudy the distributions and structures of supramols. Long end-associative polymers are as effective as ultralong\nlinears-and have excellent shear resistance. Specifically, megasupramols. control post impact misting,\nwhich prevents hot fireballs from forming. In addn., megasupramols. reduce turbulent drag without degrading,\nrelevant to energy conservation in fuel distribution pipelines. These \"megasupramoleules\" have no adverse\neffect on power output, fuel efficiency or emissions in unmodified diesel engines. In fact, they provide a 12\u0302\n(p=0.002) redn. in diesel soot.", "date": "2015-03", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "249", "publisher": "American Chemical Society", "pagerange": "PMSE-49", "id_number": "CaltechAUTHORS:20150407-131420618", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150407-131420618", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2015", "author_list": "Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/zvp62-3wg14", "eprint_id": 53601, "eprint_status": "archive", "datestamp": "2023-08-20 04:43:47", "lastmod": "2023-10-19 21:54:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Fu-Amy", "name": { "family": "Fu", "given": "Amy" } }, { "id": "Gwon-Kihak", "name": { "family": "Gwon", "given": "Kihak" } }, { "id": "Kim-Mihye", "name": { "family": "Kim", "given": "Mihye" } }, { "id": "Tae-Giyoong", "name": { "family": "Tae", "given": "Giyoong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Visible-Light-Initiated Thiol\u2212Acrylate Photopolymerization of Heparin-Based Hydrogels", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. \n\nReceived: October 21, 2014. Revised: December 16, 2014. Publication Date (Web): December 23, 2014. \n\nThis project was supported by the \"GIST-Caltech Research Collaboration Project\" through a grant provided by the Gwangju Institute of Science and Technology, Korea. We thank Dr. Matthew Mattson and Karthik Ramachandran for their assistance in using ZEMAX ray tracing software.\n\nSupplemental Material - bm501543a_si_001.pdf
", "abstract": "An in situ heparin-based forming hydrogel that cures under visible-light is formulated using eosin Y as a photoinitiator with triethanolamine as an electron donor to initiate reaction of thiolated-heparin with acrylate-ended poly(ethylene glycol). Formulations and irradiation conditions are presented for control of heparin content (1.6 to 3.3% w/v), modulus (100\u201310\u202f000 Pa), and gelation time (30\u2013600 s). Encapsulation of 3T3 fibroblasts in the hydrogel gave over 96% viability for all conditions examined. In vitro characterization of epidermal growth factor released from the hydrogel confirmed that the growth factor remains bioactive. The ability to deliver growth factors, fast gelation kinetics under visible light, and independent control of physical and biochemical properties makes this system a promising candidate for use in regenerative medicine. In particular, irradiation conditions that achieve gelation in 150s are compatible with the stringent light exposure limits of the retina, which affords a wide safety margin for use with other tissues.", "date": "2015-02", "date_type": "published", "publication": "Biomacromolecules", "volume": "16", "number": "2", "publisher": "American Chemical Society", "pagerange": "497-506", "id_number": "CaltechAUTHORS:20150113-070659617", "issn": "1525-7797", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150113-070659617", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Gwangju Institute of Science and Technology, Korea" } ] }, "doi": "10.1021/bm501543a", "primary_object": { "basename": "bm501543a_si_001.pdf", "url": "https://authors.library.caltech.edu/records/zvp62-3wg14/files/bm501543a_si_001.pdf" }, "resource_type": "article", "pub_year": "2015", "author_list": "Fu, Amy; Gwon, Kihak; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/tv2xy-be341", "eprint_id": 61301, "eprint_status": "archive", "datestamp": "2023-08-20 04:11:14", "lastmod": "2024-01-13 16:26:29", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Boyu", "name": { "family": "Li", "given": "Boyu" } }, { "id": "Kim-Joey", "name": { "family": "Kim", "given": "Joey" }, "orcid": "0000-0002-3359-4875" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "A Molecular Picture for the Thermo-Reversibility of Gels Formed by Isophthalic Acid-Ended Telechelic Polymers", "ispublished": "unpub", "full_text_status": "public", "note": "\u00a9 2015 Materials Research Society.\n\nPublished - Boyu_2015p2110340.pdf
", "abstract": "We demonstrate that isophthalic acid-ended telechelic poly(1,5-cyclooctadiene)s (A-PCODs) form thermo-reversible gels in non-polar solvent with a unique molecular mechanism for their thermo-reversibility. Like other associative telechelic polymers, A-PCODs form \"flower-like\" micelles at low concentration and form gels through bridging at higher concentration which exhibit linear viscoelasticity. However, unlike the widely studied hydrophobically end-capped PEOs, A-PCODs show clear thermo-reversibility in viscosity and dynamic modulus around 30 \u00b0C due to the hydrogen-bonding end groups. In addition, they differ from other reported thermo-reversible gelators (eg. Pluronics, PNIPAm containing block copolymers, etc.): neither the end group nor the backbone in the present system has a critical solution temperature within the measured temperature range (0 \u00b0C to 60 \u00b0C), indicating that the present system has a unique mechanism for its thermo-reversibility. To obtain a molecular picture of the mechanism, rheology and small angle neutron scattering (SANS) studies were implemented. Topological changes above the transition temperature (30 \u00b0C) were observed in both oscillatory rheology and SANS. SANS reveals that the size of clusters, which are formed by interacting micelles, depends highly on temperature (T) but independent of polymer concentration. These results cannot be explained by current theories on associative telechelic polymers which assume constant and large aggregation number of end groups at all temperatures and concentrations. We hypothesize that the temperature-sensitive sol-gel transition is due to a decrease in aggregation number for T above the critical temperature in our system, and this temperature-dependence of aggregation number is further determined by the chemical structure and hydrogen-bonding property of isophthalic acid ends.", "date": "2015", "date_type": "published", "publisher": "Materials Research Society", "id_number": "CaltechAUTHORS:20151020-080830474", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151020-080830474", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Li-D", "name": { "family": "Li", "given": "D." } } ] }, "doi": "10.1557/opl.2015.638", "primary_object": { "basename": "Boyu_2015p2110340.pdf", "url": "https://authors.library.caltech.edu/records/tv2xy-be341/files/Boyu_2015p2110340.pdf" }, "resource_type": "book_section", "pub_year": "2015", "author_list": "Li, Boyu; Kim, Joey; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/jvwv9-c1v43", "eprint_id": 56077, "eprint_status": "archive", "datestamp": "2023-08-20 02:30:36", "lastmod": "2023-10-20 23:37:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Pirogovsky-P", "name": { "family": "Pirogovsky", "given": "Paul" } }, { "id": "Hule-R-A", "name": { "family": "Hule", "given": "Rohan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Anisotropy across length scales: Conformation and self-assembly of coil-liquid crystal diblock coplymers in nematic solvent", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Coil- Liq. Cryst. diblock copolymers exhibit ordered morphologies in liq. crystal (LC) solvent that reflect the interplay\nbetween microphase segregation of the coil (LC phobic) block and the spontaneous anisotropy in the local chain\nconformation of the LC block. The self- assembly of \"end- on\" and \"side- on\" coil- LC diblock copolymers with near const.\nside group liq. crystal polymer (SGLCP) block lengths and increasing coil (polystyrene) block lengths (40 kg /mol to 120 kg\n/mol) was investigated using SANS and TEM. SANS measurements of dil. solns. of these coil- SGLCP diblocks in aligned\nnematic LC solvent reveal the formation of anisotropic, self- assembled micelles. Unstained and pos.- stained TEM enabled a\ndirect correspondence between the structural features found in the anisotropic scattering and micelle sizes. Size scales of the\nmorphol. features at both at the network (>100 nm) and intrachain (5- 100 nm) levels were examd. The shape and\nanisotropy of the micelle core appears to depend on both the SGLCP block and the polystyrene block lengths.", "date": "2014-08-10", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "248", "publisher": "American Chemical Society", "pagerange": "611-PMSE", "id_number": "CaltechAUTHORS:20150325-133945135", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150325-133945135", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Kurji, Zuleikha; Pirogovsky, Paul; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/3fdg5-dtm27", "eprint_id": 55956, "eprint_status": "archive", "datestamp": "2023-08-20 02:28:02", "lastmod": "2023-10-20 23:28:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Takagi-Akira", "name": { "family": "Takagi", "given": "Akira" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Interplay between end-association and entanglement in hydrogen-bonded telechelic polymers: A sticky situation", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "A relatively new class of supramols.-highly entangled, end-functional polymers-are accessible through efficient\nROMP+CTA (ring-opening metathesis polymn. with chain transfer agents) synthesis. At high concn. or in the\nmelt, assocn. among the end-groups of entangled chains (>25 M_e) frustrates their reptation relaxation. This\nbroadens the time range in which the materials behave in an elastomeric manner. The activation energy of\nend-assocn. can be tuned using polyvalent hydrogen bonding. Here, we compare polybutadienes that have\neither two or four carboxylate groups at each end. The activation energy for end-assocn. controls the time\nscale and temp. dependence of the terminal relaxation. For example, having two carboxylates at each end\nslows the terminal relaxation of a 50kg/mol PB by three orders of magnitude at ambient temp.-and by more\nthan four orders of magnitude at 5\u00b0C. Thus, the terminal relaxation shifts more strongly with temp. than the\nchain segmental motion, giving an enlightening failure of time-temp. superposition. Two relaxation modes are\nevident: a \"fast mode\" assigned to the rearrangement of entangled chains constrained by end assocn. and a\n\"slow mode\" assigned to the end group exchange. Adding short polybutadiene as a dilutent helps to expose\nthe underlying dynamics and leads to interesting adhesive materials.", "date": "2014-08-10", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "248", "publisher": "American Chemical Society", "pagerange": "523-PMSE", "id_number": "CaltechAUTHORS:20150323-084316686", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150323-084316686", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Takagi, Akira and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/83gr4-55p44", "eprint_id": 48306, "eprint_status": "archive", "datestamp": "2023-08-20 02:04:56", "lastmod": "2023-10-17 18:41:30", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Pirogovsky-P", "name": { "family": "Pirogovsky", "given": "Paul" } }, { "id": "Hule-R-A", "name": { "family": "Hule", "given": "Rohan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Anisotropy across length scales: Conformation and self-assembly of coil-liquid diblock coplymers in nematic solvent", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Coil-Liq. Cryst. diblock copolymers exhibit ordered morphologies in liq. crystal (LC) solvent that reflect the interplay between microphase segregation of the coil (LC phobic) block and the spontaneous anisotropy in the local chain conformation of the LC block. The self-assembly of \"end-on\" and \"side-on\" coil-LC diblock copolymers with near const. side group liq. crystal polymer (SGLCP) block lengths and increasing coil (polystyrene) block lengths (40 kg/mol to 120 kg/mol) was investigated using SANS and TEM. SANS measurements of dil. solns. of these coil-SGLCP diblocks in aligned nematic LC solvent reveal the formation of anisotropic, self-assembled micelles. Unstained and pos.-stained TEM enabled a direct correspondence between the structural features found in the anisotropic scattering and micelle sizes. Size scales of the morphol. features at both at the network (>100 nm) and intrachain (5-100 nm) levels were examd. The shape and anisotropy of the micelle core appears to depend on both the SGLCP block and the polystyrene block lengths.", "date": "2014-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20140811-125620250", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140811-125620250", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2014", "author_list": "Kurji, Zuleikha; Pirogovsky, Paul; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dnpev-1tm75", "eprint_id": 48312, "eprint_status": "archive", "datestamp": "2023-08-20 02:05:26", "lastmod": "2023-10-17 18:41:50", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Boyu", "name": { "family": "Li", "given": "Boyu" } }, { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Mega-supramolecules by end-association of very long telechelics: Highly potent rheological modifiers and mist controllers", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "To form mega linear supramols. by assocn. of telechelic polymers at concn. as low as possible, very long chain lengths are used; telechelic polymers with Mw>400 kg/mol were synthesized to mimic multimillion MW polymers as rheol. modifiers-and they did. Building on the Hilmyer-Macosco protocol for ROMP of cyclooctadiene with CTAs bearing end-groups, improvements in monomer purifn. enabled synthesis of telechelics with unprecedented length. Steady shear viscometry confirmed the dramatic enhancement in the rheol. effect brought by longer backbone length. And pairwise associative telechelics showed more potent rheol. consequences comparing to self-associative ones; esp. in mist-control effect. Mega-linear polymers (Mw > 1e6 g/mol) have been known for decades to suppress mist formation and improve fuel safety under severe impact (Figure 2a). However, their use is limited by \"shear degrdn.,\" (Figure 2b). Long pairwise associative polymers are as effective as mega-linears-and have excellent shear resistance (Figure 2d). GPC-MALLS and SANS were performed to study the distributions and structures of supramols.", "date": "2014-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20140811-131024568", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140811-131024568", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2014", "author_list": "Li, Boyu; Wei, Ming-Hsin; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/f02bb-f5e86", "eprint_id": 48308, "eprint_status": "archive", "datestamp": "2023-08-20 02:05:03", "lastmod": "2023-10-17 18:41:37", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } }, { "id": "Li-Boyu", "name": { "family": "Li", "given": "Boyu" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Synthesis and potency of long end-associative polymers for mist control", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Long linear 1, 4-polybutadienes end-functionalized with associative groups were studied as additives to hydrocarbon fluids to mitigate the fire hazard of their mist in crash scenarios. These polymers were molecularly designed to overcome both the shear-degrdn. of long polymer chains in turbulent flows, and the chain collapse induced by the random placement of associative groups along polymer backbones. Linear polymers with discrete nos. of carboxyl groups on chain ends were investigated first: an innovative synthetic strategy was devised to achieve unprecedented backbone lengths and precise control of the no. of carboxyl groups on chain ends (N). A very narrow range of N was found to allow both sufficient end-assocn. strength and polymer soly. in apolar media. Shear rheol. revealed the end-assocn. of very long chains in apolar media leads to the formation of flower-like micelles interconnected by bridging chains. The polymer with N = 4 and Mw= 430 kg/mol was found shear-resistant, effective in providing fire protection to jet fuel at concns. as low as 0.3wt%, well-sol. in jet fuel ranging from -30 to +70\u00b0C, and showing little interference with dewatering. Four pairs of complementary associative end-groups of varying strengths were also investigated, in the hope of achieving supramols. with both mist-control ability and better utilization of polymer building blocks. Shear rheol. revealed the strength of complementary end-assocn. required to achieve supramols. capable of modulating soln. rheol. properties.", "date": "2014-08", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20140811-130435415", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140811-130435415", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2014", "author_list": "Wei, Ming-Hsin; Li, Boyu; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/m0xec-wc975", "eprint_id": 60166, "eprint_status": "archive", "datestamp": "2023-08-20 01:23:20", "lastmod": "2023-10-20 23:05:55", "type": "patent", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Flagan-R-C", "name": { "family": "Flagan", "given": "Richard C." }, "orcid": "0000-0001-5690-770X" } ] }, "title": "Systems and methods for concentrating solar energy without tracking the sun", "ispublished": "unpub", "full_text_status": "public", "note": "Publication number\tUS8748730B2.\nPublication type\tGrant.\nPublication date\tJune 10, 2014.\nApplication number\tUS20100258170A1.\nApplication publication date Oct. 14, 2010.\nFiling date\tMar 13, 2010.\nPriority date\tMar 13, 2009.\n\nGovernment Interests: The U.S. Government has certain rights in this invention pursuant to Grant No. DMR0505393 awarded by the National Science Foundation.\n\nParent Case Text: The present application claims the benefit of U.S. Provisional Application No. 61/160,108, filed Mar. 13, 2009, entitled \"Concentrating Solar Energy--Without Tracking the Sun\", the entire content of which is incorporated herein by reference.\n\nPublished - US20100258170.pdf
Published - US8748730B2.pdf
", "abstract": "Systems and methods for concentrating solar energy without tracking the sun are provided. In one embodiment, the invention relates to a solar collector assembly for collecting and concentrating light for solar cell assemblies, the collector assembly including an array of solar collectors, each including a funnel shaped collector including a side wall defining a tapered opening having a base aperture and an upper aperture, the side wall including an outer surface, and a solar cell assembly positioned at the base aperture, where the outer surface is coated with a material that substantially reflects light, where the upper aperture is wider than the base aperture, where the funnel shaped collector is configured to substantially confine light, incident via the upper aperture, within the funnel shaped collector until the light exits proximate the base aperture, and where the solar cell assembly is configured to capture light exiting the base aperture.", "date": "2014-06-10", "date_type": "published", "publisher": "U.S. Patent Office", "id_number": "CaltechAUTHORS:20150910-090608953", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150910-090608953", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR0505393" } ] }, "primary_object": { "basename": "US20100258170.pdf", "url": "https://authors.library.caltech.edu/records/m0xec-wc975/files/US20100258170.pdf" }, "related_objects": [ { "basename": "US8748730B2.pdf", "url": "https://authors.library.caltech.edu/records/m0xec-wc975/files/US8748730B2.pdf" } ], "resource_type": "patent", "pub_year": "2014", "author_list": "Kornfield, Julia A. and Flagan, Richard C." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/web5m-ff411", "eprint_id": 46402, "eprint_status": "archive", "datestamp": "2023-08-22 12:47:49", "lastmod": "2023-10-26 19:43:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tiboni-M", "name": { "family": "Tiboni", "given": "Marcela" } }, { "id": "Grzybowski-A", "name": { "family": "Grzybowski", "given": "Adelia" } }, { "id": "Bald-G-R", "name": { "family": "Baldo", "given": "Gizele Rejane" } }, { "id": "Dias-E-F-Jr", "name": { "family": "Dias", "given": "Edson Flausino, Jr." } }, { "id": "Tanner-R-D", "name": { "family": "Tanner", "given": "Robert D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia Ann" }, "orcid": "0000-0001-6746-8634" }, { "id": "Fontana-J-D", "name": { "family": "Fontana", "given": "Jos\u00e9 Domingos" } } ] }, "title": "Thermopressurized diluted phosphoric acid pretreatment of ligno(hemi)cellulose to make free sugars and nutraceutical oligosaccharides", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Bifidobacteria; Lactobacilli; Galactoglucomannan oligosaccharides; Xylo-oligosaccharides", "note": "\u00a9 2014 Society for Industrial Microbiology and Biotechnology.\n\nReceived: 12 December 2013; Accepted: 19 February 2014; Published online: 18 April 2014.\n\nThe authors would like to thank the National Council for Scientific and Technological Development (CNPq), the Coordination for the Improvement of Higher Education Personnel (CAPES), and the Araucaria Foundation from SETI-PR.", "abstract": "Ligno(hemi)cellulosics (L(h)Cs) as sugarcane bagasse and loblolly pine sawdust are currently being used to produce biofuels such as bioethanol and biobutanol through fermentation of free sugars that are often obtained enzymatically. However, this bioconversion requires a pretreatment to solubilize the hemicellulose fractions, thus facilitating the action of the cellulolytic enzymes. Instead of the main free monosaccharides used in these current models, the modulation of thermopressurized orthophosphoric acid as a pretreatment, in the ranges of 3\u201312 atm and pH 1.5\u20132.5, can produce nondigestible oligosaccharides (NDOS) such as xylo-oligosaccharides (XOS) because heteroxylan is present in both types of hardwood and softwood hemicelluloses. A comparative thin-layer chromatographic analysis of the hydrolytic products showed the best conditions for NDOS production to be 7 atm/water, pH 2.25 and 2.50, and 8.5 atm/water for both sources. Particular hydrolysates from 7 atm (171 \u00b0C) at pHs 2.25 and 2.50 both for cane bagasse and pine sawdust, with respective oligosaccharide contents of 57 and 59 %, once mixed in a proportion of 1:1 for each plant source, were used in vitro as carbon sources for Bifidobacterium or Lactobacillus. Once both bacteria attained the stationary phase of growth, an unforeseen feature emerged: the preference of B. animalis for bagasse hydrolysates and, conversely, the preference of L. casei for pine hydrolysates. Considering the fact that nutraceutical oligosaccharides from both hemicelluloses correspond to higher value-added byproducts, the technology using a much diluted thermopressurized orthophosphoric acid pretreatment becomes an attractive choice for L(h)Cs.", "date": "2014-06", "date_type": "published", "publication": "Journal of Industrial Microbiology and Biotechnology", "volume": "41", "number": "6", "publisher": "Springer", "pagerange": "957-964", "id_number": "CaltechAUTHORS:20140620-134714828", "issn": "1367-5435", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140620-134714828", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Conselho Nacional de Desenvolvimento Cient\u00edfico e Tecnol\u00f3gico (CNPq)" }, { "agency": "Coordena\u00e7\u00e3o de Aperfei\u00e7oamento de Pessoal de N\u00edvel Superior (CAPES)" }, { "agency": "SETI-PR Araucaria Foundation" } ] }, "doi": "10.1007/s10295-014-1426-3", "resource_type": "article", "pub_year": "2014", "author_list": "Tiboni, Marcela; Grzybowski, Adelia; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0tkn3-75r04", "eprint_id": 55776, "eprint_status": "archive", "datestamp": "2023-08-20 00:00:38", "lastmod": "2023-10-20 23:09:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Yanfei", "name": { "family": "Li", "given": "Yanfei" } }, { "id": "Brockman-C", "name": { "family": "Brockman", "given": "Christopher" } }, { "id": "Yates-D", "name": { "family": "Yates", "given": "Daniel" } }, { "id": "McKenna-G-B", "name": { "family": "McKenna", "given": "Gregory" }, "orcid": "0000-0002-5676-9930" }, { "id": "Schroeder-C-M", "name": { "family": "Schroeder", "given": "Charles" } }, { "id": "San-Francisco-M", "name": { "family": "San Francisco", "given": "Michael" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Anderson-R", "name": { "family": "Anderson", "given": "Rae" } } ] }, "title": "Comparison of the coil-stretch transition of linear and circular DNA in planar extensional flow", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Understanding the elongational flow behavior of macromols. is of great interest due to its application in turbulent drag redn.\nand fiber spinning. It was predicted by P.G. De Gennes in 1974 that above a crit. extension rate, a coiled polymer would\nexperience a coil-stretch transition (CST) to adopt a relatively open configuration. This has been proven to be true for\nlinear polymers by both birefringence and microfluidic techniques. On the other hand, understanding the extensional\nbehavior of ring-like polymers is vital due to its application in the gene therapy studies using plasmid DNA. However, it\nremains unknown whether ring-like polymers exhibit a similar transition, and, if so, how their CST behavior compares with\nthat of linear counterparts. In the present investigation, we examine the dynamics of large ring-like and linear DNA mols.\nwith the goal of providing fundamental data related to the coil-stretch transition (CST), hysteresis in CST, and mol.\nindividualism. To do this, we combined biol. synthesis of DNA mols. following the procedures of D.E. Smith and coworkers\nwith direct imaging of fluorescently labeled DNA at the stagnation point in a novel microfluidic device that has a cross-slot\ndesign to develop a stagnation point extensional flow that permits direct imaging of the fluorescently labeled DNA.\nPreliminary results show for 45 kbp DNAs that both cyclic and linear DNA exhibit CST at a Weissenberg no. close to 0.5,\ncorresponding to a faster extension rate for the ring-like DNA (which has a relaxation time three times faster than a linear\nDNA of the same mol. wt.). Results will be presented for a range of DNA and circular DNA contour lengths.", "date": "2014-03-16", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "247", "publisher": "American Chemical Society", "pagerange": "420-PMSE", "id_number": "CaltechAUTHORS:20150316-093513196", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150316-093513196", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Li, Yanfei; Brockman, Christopher; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/qghwd-zjy08", "eprint_id": 55770, "eprint_status": "archive", "datestamp": "2023-08-20 00:00:04", "lastmod": "2023-10-20 23:09:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Li-Boyu", "name": { "family": "Li", "given": "Boyu" } }, { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } } ] }, "title": "Mega-supramolecules by end-association of very long telechelics: Highly potent rheology modifiers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "To favor linear end-to-end assocn. of telechelic polymers, very long chain lengths are used to inhibit cyclic configurations.\nSpecifically, based on theor. predictions, telechelic polymers with high mol. wt. (Mw>400k g/mol) were synthesized to see if\nthey could mimic multi- million MW polymers- and they did (in shear rheol. and mist suppression). Building on the Hilmyer-\nMacosco protocol for ROMP of cyclooctadiene with CTAs bearing functional groups, improvements in monomer purifn. enabled\nsynthesis of telechelics with unprecedented length. The importance of chain length was confirmed by examg. telechelics\nfrom 75k to >400k g/mol. To test theor. expectations that donor-acceptor assocn. would yield more potent rheol. modifiers\nthan self-assocn., carboxylate- functional telechelics were paired with amine-functional ones and they did increase viscosity\nmore strongly than self-assocg. chains of similar assocn. energy, length and concn. Motivated by rheol. evidence of difference\nin supramol. structures, SANS measurements were performed and preliminary results correspond with theor. expectations.", "date": "2014-03-16", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "247", "publisher": "American Chemical Society", "pagerange": "52-PMSE", "id_number": "CaltechAUTHORS:20150316-085805066", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150316-085805066", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Kornfield, Julia A.; Li, Boyu; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/z7hqg-n3s28", "eprint_id": 45104, "eprint_status": "archive", "datestamp": "2023-08-19 23:38:45", "lastmod": "2023-10-26 17:33:44", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Fu-Amy", "name": { "family": "Fu", "given": "Amy" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Electrospun nanofibrous scaffolds for the promotion of scar-free corneal wound healing", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Transparency of the healthy cornea comes from its highly ordered nanostructure, which is maintained by specialized fibroblast\ncells. During corneal injury, these cells differentiate into repair cells - myofibroblasts - which close the wound and remodel the\ntissue. However, myofibroblasts contain stress fibers that distort the cornea's refracting surface. Efforts to develop wound\nhealing materials have been largely unsuccessful for corneal applications, where stringent optical requirements necessitate a\ntransparent wound dressing to foster scar-free tissue remodeling. We approach this problem with a protein-polymer scaffold\nthat contains electrospun nanofibers characteristic of the highly-ordered structure of the healthy cornea. We examine\nmyofibrobalst responses to electrospun nanofiber mats in-vitro using a mock wound healing assay, ex-vivo using intact rabbit\neyes and in-vivo using a mouse model. We show that the material is well-suited for corneal applications because of its\ntransparency, ability to recruit epithelial and fibroblast cells and capability to regulate the fibroblast repair phenotype.", "date": "2014-03", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20140422-091325621", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140422-091325621", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2014", "author_list": "Fu, Amy and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/sgg0p-bzh82", "eprint_id": 44909, "eprint_status": "archive", "datestamp": "2023-08-19 23:36:59", "lastmod": "2023-10-26 17:22:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Li-Boyu", "name": { "family": "Li", "given": "Boyu" } }, { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } } ] }, "title": "Mega-supramolecules by end-association of very long telechelics: Highly potent rheology modifiers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "To favor linear end-to-end assocn. of telechelic polymers, very long chain lengths are used to inhibit cyclic configurations.\nSpecifically, based on theor. predictions, telechelic polymers with high mol. wt. (Mw>400k g/mol) were synthesized to see if\nthey could mimic multi-million MW polymers-and they did (in shear rheol. and mist suppression). Building on the Hilmyer-\nMacosco protocol for ROMP of cyclooctadiene with CTAs bearing functional groups, improvements in monomer purifn. enabled\nsynthesis of telechelics with unprecedented length. The importance of chain length was confirmed by examg. telechelics\nfrom 75k to >400k g/mol. To test theor. expectations that donor-acceptor assocn. would yield more potent rheol. modifiers than\nself-assocn., carboxylate-functional telechelics were paired with amine-functional ones and they did increase viscosity more\nstrongly than self-assocg. chains of similar assocn. energy, length and concn. Motivated by rheol. evidence of differences in\nsupramol. structures, SANS measurements were performed and preliminary results correspond with theor. expectations.", "date": "2014-03", "date_type": "published", "publication": "PMSE Preprints", "publisher": "American Chemical Society", "pagerange": "PMSE-52", "id_number": "CaltechAUTHORS:20140414-085916058", "issn": "1550-6703", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-085916058", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Kornfield, Julia A.; Li, Boyu; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/gawq6-w0804", "eprint_id": 45102, "eprint_status": "archive", "datestamp": "2023-08-19 23:38:39", "lastmod": "2023-10-26 17:33:40", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Miller-S-E", "name": { "family": "Miller", "given": "Sophie E." } }, { "id": "Sun-Wei", "name": { "family": "Sun", "given": "Wei" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Nanoparticle-decorated honeycomb-structured polymeric films via breath figures with Janus particles", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Microporous polymer scaffolds decorated with nanoparticles could provide functional membranes that are\nneeded in solar-to-fuel technologies. Therefore, efficient prodn. processes are needed for high surface area,\nporous membranes with distinct catalytic nanoparticles on opposite sides of a support that resists oxidn. and\nseparates the products, e.g., hydrogen and oxygen. Breath figure (BF) patterning is an established method\nto create microstructured honeycomb-patterned porous polymer films. This research shows that surfaceactive\nnanoparticles can self-assemble onto the interfaces between the templating BF water droplets and the\npolymer soln. to control micrometer and nanometerscale hierarchical structure. Here, amphiphilic \"Janus\"\nnanoparticles serve as both solid surfactants and Pickering emulsion stabilizing agents, thus able to optimize\nordering degree of the honeycomb structures and nanoparticle enrichment in the pore walls. Janus\nnanoparticles were synthesized using literature methods (with improvements that will be presented):\nfunctionalizing only the exposed surface of particles embedded on the surface of wax microspheres\n(colloidosomes) renders half of the particle hydrophobic. They were then employed in the BFs templating\nmethod for the first time, resulting in regular, porous films with uniform, high nanoparticle d. Humble\nmaterials (silica and polystyrene) demonstrate the method, and can now be replaced by catalyst\nnanoparticles (e.g., nickel, molybdenum sulfide, or cobalt-based) embedded in a semiconducting polymer to\ncreate membranes for photocatalytic water splitting.", "date": "2014-03", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20140422-090849228", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140422-090849228", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2014", "author_list": "Miller, Sophie E.; Sun, Wei; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/aeyn9-32n44", "eprint_id": 37852, "eprint_status": "archive", "datestamp": "2023-08-19 19:10:56", "lastmod": "2023-10-23 19:03:27", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Fu-Amy", "name": { "family": "Fu", "given": "Amy" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Electrospun nanofibrous scaffolds for the promotion of scarfree corneal wound healing", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2013 American Chemical Society.", "abstract": "Irregular healing following corneal injury accounts for approx. 1.5 million new cases of\nmonocular blindness every year. Unlike cataracts, such cases of blindness are irreversible\nwithout corneal transplantation. Efforts to develop biomaterials that promote wound\nhealing have been largely unsuccessful for corneal applications, where stringent optical\nrequirements necessitate a transparent wound dressing to promote host-cell infiltration\nand foster scar-free tissue remodeling. We approach this problem with a novel proteinpolymer\nscaffold that contains nanofibrillar elements characteristic of the highly-ordered\nstructure of a healthy corneal stroma. To evaluate the role of this fibrillar nanostructure,\nwe examine cell responses to electrospun nanofiber mats both in-vitro and in-vivo. We\nshow that the material is well-suited for corneal applications because of its transparency,\nability to recruit epithelial and fibroblast cells and capability to regulate the fibroblast repair\nphenotype.", "date": "2013-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20130410-102006664", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130410-102006664", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2013", "author_list": "Fu, Amy and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/a851x-tv327", "eprint_id": 37857, "eprint_status": "archive", "datestamp": "2023-08-19 19:11:02", "lastmod": "2023-10-23 19:03:41", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Melt relaxation dynamics as a function of ring-expansion polymerization conditions", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2013 American Chemical Society.", "abstract": "Melt viscoelastic properties of the products of ring-expansion metathesis (REMP) reveal\nstructural changes that relate to the catalyst structure and reaction conditions.\nConsideration of the rates of monomer addn., intramol. chain transfer, interchain fusion\nand catalyst release provides insight into variations in the relaxation dynamics of the\nresulting melts.", "date": "2013-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20130410-105513446", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130410-105513446", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2013", "author_list": "Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/n2g43-z6807", "eprint_id": 37813, "eprint_status": "archive", "datestamp": "2023-08-19 19:10:01", "lastmod": "2023-10-23 18:05:08", "type": "conference_item", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Hule-R-A", "name": { "family": "Hule", "given": "Rohan" } }, { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Pirogovsky-P", "name": { "family": "Pirogovsky", "given": "Paul" } } ] }, "title": "Self-assembly of coil-liquid crystal (LC) diblocks in LC solvent: Hierarchies of anisotropies", "ispublished": "unpub", "full_text_status": "restricted", "note": "\u00a9 2013 American Chemical Society.", "abstract": "Spontaneous anisotropy in the local chain conformation of Side-Group Liq. Cryst. Polymers\n(SGLCPs) drives the formation of anisotropic self-assembled microstructures of diblock\ncopolymers consisting of an SGLCP block and a random coil block when dissolved in a\nsmall mol. LC, as obsd. by SANS and TEM. A phys.-inspired, segment-based model allows\nus to predict scattering profiles for different proposed arrangements of the block\ncopolymers within the microstructure. Predicted scattering patterns, spanning the range\nfrom the overall assembly (>100nm) to the intrachain scale (5-100nm), are compared with\nthe obsd. scattering profiles to discriminate between different possible self-assembled\nstructures.", "date": "2013-04", "date_type": "published", "publisher": "Caltech Library", "id_number": "CaltechAUTHORS:20130408-154331705", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130408-154331705", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "conference_item", "pub_year": "2013", "author_list": "Kornfield, Julia A.; Hule, Rohan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/08s84-4mq92", "eprint_id": 37681, "eprint_status": "archive", "datestamp": "2023-08-19 14:48:01", "lastmod": "2023-10-23 17:56:27", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Bo", "name": { "family": "Shen", "given": "Bo" } }, { "id": "Liang-Yongri", "name": { "family": "Liang", "given": "Yongri" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Han-Charles-C", "name": { "family": "Han", "given": "Charles C." } } ] }, "title": "Mechanism for Shish Formation under Shear Flow: An Interpretation from an in Situ Morphological Study", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society.\n\nReceived: November 20, 2012;\nRevised: January 23, 2013;\nPublished: February 11, 2013.\n\n\nThis work has been financially supported by NSFC Project\n50930003.\n\nThe authors declare no competing financial interest.\n\nPublished - ma3023958.pdf
Supplemental Material - ma3023958_si_001.pdf
", "abstract": "Isotactic polypropylene has been systematically studied with in situ optical microscopy to obtain a real space view of the morphology evolution of shear induced crystallization as a function of shear rates and shear time to elucidate the mechanism of shish formation. The critical shear time for inception of shish formation on the shear rate have provided an important understanding of the molecular and entangled network relaxation in relation to the shish formation. Also the observation of a typical shear time dependent comet like shish-kebab structure formation on the interface and the morphological growth of the shish from a fiber inside our sample have led to a new hypothesis that the shish is formed through a multiple discrete steps instead of forming directly to the final most stable state, this means that a transition state may be existed before shish growth. Two steps shear experiments with various time intervals between each step were designed to verify our proposed transition state mechanism, which can be observed much directly and obviously through real-space morphology, especially at low shear rate with long shear time. Another time dependent relaxation time is introduced base on shear rate dependent experiment after the first step shear and has close relationship with the existence of the critical shear time. A general framework for the shish formation has been established which can capture all the observed morphological features well, including the existence of the critical shear time at a given shear rate.", "date": "2013-02-26", "date_type": "published", "publication": "Macromolecules", "volume": "46", "number": "4", "publisher": "American Chemical Society", "pagerange": "1528-1542", "id_number": "CaltechAUTHORS:20130329-081350926", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130329-081350926", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSFC Project", "grant_number": "50930003" } ] }, "doi": "10.1021/ma3023958", "primary_object": { "basename": "ma3023958_si_001.pdf", "url": "https://authors.library.caltech.edu/records/08s84-4mq92/files/ma3023958_si_001.pdf" }, "related_objects": [ { "basename": "ma3023958.pdf", "url": "https://authors.library.caltech.edu/records/08s84-4mq92/files/ma3023958.pdf" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Shen, Bo; Liang, Yongri; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/xsgjt-pkz95", "eprint_id": 35171, "eprint_status": "archive", "datestamp": "2023-08-19 12:30:32", "lastmod": "2023-10-20 15:47:36", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ronca-S", "name": { "family": "Ronca", "given": "S." }, "orcid": "0000-0003-3434-6352" }, { "id": "Forte-G", "name": { "family": "Forte", "given": "G." } }, { "id": "Ailianou-A", "name": { "family": "Ailianou", "given": "A." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Rastogi-S", "name": { "family": "Rastogi", "given": "S." } } ] }, "title": "Direct Route to Colloidal UHMWPE by Including LLDPE in Solution during Homogeneous Polymerization of Ethylene", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society.\n\nReceived: July 19, 2012.\nAccepted: August 17, 2012.\nPublished: August 24, 2012.\nA.A. and J.A.K. acknowledge funding provided by the U.S.\nNational Science Foundation under grant DMR-0710662-Materials World Network.\n\nPublished - mz300369x.pdf
Supplemental Material - mz300369x_si_001.pdf
", "abstract": "The usual aggregation and precipitation driven by crystallization of nascent PE during homogeneous polymerization of ultra-high molecular weight polyethylene (UHMWPE) is inhibited by including linear low-density polyethylene (LLDPE) in the catalyst solution prior to addition of ethylene monomer. Co-crystallization of newly formed PE and dissolved LLDPE creates a polymer brush on the fold surfaces of the nascent crystallites. Consequently, aggregation is inhibited by steric stabilization. Scanning electron microscopy (SEM) images show that individual lamellae (approximately 10\u201320 nm thick) typically have lateral dimensions of 0.5 \u03bcm \u00d7 3.5 \u03bcm and form \"bowtie\" shaped stacks that are approximately 200\u2013500 nm thick. This simple method for stabilizing nascent crystals against precipitation is enabling fundamental studies of their metastable \"disentangled\" state and may open scalable routes to compounding UHMWPE.", "date": "2012-09", "date_type": "published", "publication": "ACS Macro Letters", "volume": "1", "number": "9", "publisher": "American Chemical Society", "pagerange": "1116-1120", "id_number": "CaltechAUTHORS:20121030-094207306", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121030-094207306", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Materials World Network", "grant_number": "DMR-0710662" } ] }, "doi": "10.1021/mz300369x", "primary_object": { "basename": "mz300369x.pdf", "url": "https://authors.library.caltech.edu/records/xsgjt-pkz95/files/mz300369x.pdf" }, "related_objects": [ { "basename": "mz300369x_si_001.pdf", "url": "https://authors.library.caltech.edu/records/xsgjt-pkz95/files/mz300369x_si_001.pdf" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Ronca, S.; Forte, G.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/sbag9-9k884", "eprint_id": 34784, "eprint_status": "archive", "datestamp": "2023-08-19 12:24:17", "lastmod": "2023-10-19 21:52:26", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Fernandez-Ballester-L", "name": { "family": "Fernandez-Ballester", "given": "Lucia" } }, { "id": "Thurman-D-W", "name": { "family": "Thurman", "given": "Derek W." } }, { "id": "Zhou-Weijun", "name": { "family": "Zhou", "given": "Weijun" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Effect of Long Chains on the Threshold Stresses for Flow-Induced Crystallization in iPP: Shish Kebabs vs Sausages", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society. Received: January 5, 2012.\nRevised: June 2, 2012. Published: August 1, 2012. We thank Dr. Robert Sammler of Dow Chemical Company for kindly providing the matrix iPP materials used in this study. We\nare also grateful to Dr. Igors Sics and Dr. Lixia Rong of\nbeamline X27C (NSLS) for assistance in X-ray experiments.\nThe ITP workshop is acknowledged, including discussions with\nTom McLeish and Scott Milner. Funding was provided by the\nNational Science Foundation under Grant DMR-0505393. The authors declare no competing financial interest. This article posted ASAP on August 1, 2012. Figures 8 and 12\nhave been revised. The correct version posted on August 2,\n2012.\n\nPublished - ma3000384.pdf
", "abstract": "The addition of small concentrations (2 wt % or less) of ultrahigh molecular weight isotactic polypropylene (M_L ~3500 kg/mol) to a matrix of lower molecular weight chains (MS ~ 186 kg/mol, e.g. M_L/M_S ~ 20) substantially decreases the critical stress for inducing a highly oriented skin under flow-induced crystallization conditions\u2014significantly more than for blends of M_L/M_S ~ 5 (Seki et al.)\u2014and promotes the formation of point precursors and oriented \"sausage-like\" structures not observed for M_L/M_S ~ 5. These differences correlate with the onset of long chain stretching during shear: the ratio of long chains' Rouse time to short chains' disengagement time indicates that 3500 kg/mol chains can easily stretch if tethered onto a point nuclei and even when untethered. Adding 3500 kg/mol chains has strong effects that saturate beyond the overlap concentration, suggesting that an uninterrupted supply of long chains greatly accelerates formation of threads. A conceptual model is proposed that distinguishes between a critical stress for shish initiation and that for propagation.", "date": "2012-08-28", "date_type": "published", "publication": "Macromolecules", "volume": "45", "number": "16", "publisher": "American Chemical Society", "pagerange": "6557-6570", "id_number": "CaltechAUTHORS:20121009-112542596", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121009-112542596", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0505393" } ] }, "doi": "10.1021/ma3000384", "primary_object": { "basename": "ma3000384.pdf", "url": "https://authors.library.caltech.edu/records/sbag9-9k884/files/ma3000384.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Fernandez-Ballester, Lucia; Thurman, Derek W.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dsjkw-8ab48", "eprint_id": 30397, "eprint_status": "archive", "datestamp": "2023-08-19 10:26:45", "lastmod": "2023-10-17 15:41:53", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Muzhou", "name": { "family": "Wang", "given": "Muzhou" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Measuring shear strength of soft-tissue adhesives", "ispublished": "pub", "full_text_status": "restricted", "keywords": "tissue adhesion, hydrogel, stress, rheometer,\ntorsion", "note": "\u00a9 2012 Wiley Periodicals, Inc. Received 17 October 2010; revised 5 April 2011; accepted 2 June 2011. Published online 10 February 2012 in Wiley Online Library. The authors thank Dr. Michael Mackel, Dr. Matthew Mattson, and Dr. Ladan Foose for experimental suggestions and editing. We are grateful for funding from the Jacobs Institute for Molecular Engineering for Medicine at Caltech.", "abstract": "A method for evaluating strength of adhesives for hydrogels and soft tissues is presented. Quantitative measurements of shear strength for applications in tissue engineering and biomedicine are performed in torsion using a rheometer. Small, disk shaped specimens of soft biological tissues and/or hydrogels (8 mm diameter, 1\u20132 mm thick) are mounted onto rheometer tools and then bonded together using the adhesive to be tested. The torsional loading geometry imposes simple shear without deforming the planar adhesive bond, in contrast to the lap-shear test. It retains the advantages of the napkin ring test while reducing artifacts due to cutting and handling soft specimens. The method is demonstrated by measuring the shear strength of two types of biomedical adhesives (cyanoacrylate and polyethylene glycol-based) between model hydrogels (gelatin) and tissues (corneal stroma and skin).", "date": "2012-04", "date_type": "published", "publication": "Journal of Biomedical Materials Research Part B", "volume": "100B", "number": "3", "publisher": "Wiley", "pagerange": "618-623", "id_number": "CaltechAUTHORS:20120430-104835198", "issn": "1552-4973", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120430-104835198", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech Jacobs Institute for Molecular Engineering and Medicine" } ] }, "doi": "10.1002/jbm.b.31981", "resource_type": "article", "pub_year": "2012", "author_list": "Wang, Muzhou and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/yvhjz-r3153", "eprint_id": 25500, "eprint_status": "archive", "datestamp": "2023-08-19 08:02:23", "lastmod": "2023-10-24 15:55:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hu-Miao", "name": { "family": "Hu", "given": "Miao" } }, { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "McKenna-G-B", "name": { "family": "McKenna", "given": "Gregory B." }, "orcid": "0000-0002-5676-9930" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Linear Rheological Response of a Series of Densely Branched Brush Polymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2011 American Chemical Society. \n\nReceived: April 27, 2011. Revised: July 24, 2011. Publication Date (Web): August 4, 2011. \n\nThis research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-05ER46218.", "abstract": "We have examined the linear rheological responses of a series of welldefined, dense, regularly branched brush polymers. These narrow molecular weight distribution brush polymers had polynorobornene backbones with degrees of\npolymerization (DP) of 200, 400, and 800 and polylactide side chains with molecular weight of 1.4 kDa, 4.4 kDa, and 8.7 kDa. The master curves for these brush polymers\nwere obtained by time temperature superposition (TTS) of the dynamic moduli over the range from the glassy region to the terminal flow region. Similar to other long chain branched polymers, these densely branched brush polymers show a sequence of relaxation. Subsequent to the glassy relaxation, two different relaxation processes can be observed for samples with the high molecular weight (4.4 and 8.7 kDa) side chains, corresponding to the relaxation of the side chains and the brush polymer backbone. Influenced by the large volume fraction of high molecular weight side chains, these brush polymers are unentangled. The lowest plateau observed in the dynamic response is not the rubbery entanglement plateau but is instead associated with the steady state recoverable compliance. Side chain properties affect the rheological responses of these\ndensely branched brush polymers and determine their glassy behaviors.", "date": "2011-09-13", "date_type": "published", "publication": "Macromolecules", "volume": "44", "number": "17", "publisher": "American Chemical Society", "pagerange": "6935-6943", "id_number": "CaltechAUTHORS:20110929-140501977", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110929-140501977", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-05ER46218" } ] }, "doi": "10.1021/ma2009673", "resource_type": "article", "pub_year": "2011", "author_list": "Hu, Miao; Xia, Yan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/x832a-q8m14", "eprint_id": 25482, "eprint_status": "archive", "datestamp": "2023-08-19 08:02:15", "lastmod": "2023-10-24 15:54:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Smirnova-D-S", "name": { "family": "Smirnova", "given": "Diana S." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Lohse-D-J", "name": { "family": "Lohse", "given": "David J." } } ] }, "title": "Morphology Development in Model Polyethylene via\n Two-Dimensional Correlation Analysis", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2011 American Chemical Society. Received: April 11, 2011\nRevised: June 29, 2011. Publication Date (Web): August 15, 2011. We thank ExxonMobil Research and Engineering Company\n(Clinton, NJ) and funding from the National Science Foundation (DMR-0505393 and GOALI-0523083). We thank the\nbeamline scientists at X27C at NSLS BNL (Dr. Lixia Rong and\nJie Zhu). Important preliminary experiments were performed at 7.3.3 at ALS LBL with assistance from Dr. Alexander Hexemer and Eliot Gann, as well as Zuleikha Kurji (Caltech). We thank Maria Xenidou and Charles Symon for the synthesis of the polymer used in this study.", "abstract": "Two-dimensional (2D) correlation analysis is applied to synchrotron X-ray scattering data to characterize\nmorphological regimes during nonisothermal crystallization of a model ethylene copolymer (hydrogenated polybutadiene,\nHPBD). The 2D correlation patterns highlight relationships\namong multiple characteristics of structure evolution, particularly the extent to which separate features change simultaneously versus sequentially. By visualizing these relationships during cooling, evidence is obtained for two separate physical processes occurring in what is known as \"irreversible crystallization\" in random ethylene copolymers. Initial growth of primarily lamellae into unconstrained melt (\"primary-irreversible crystallization\") is distinguished from subsequent secondary lamellae formation in the constrained, noncrystalline regions\nbetween the primary lamellae (\"secondary-irreversible crystallization\"). At successively lower temperatures (\"reversible crystallization\"), growth of the crystalline reflections is found to occur simultaneously with the change in shape of the amorphous halo, which is inconsistent with the formation of an additional phase. Rather, the synchronous character supports the view that growth of frustrated crystals distorts the adjacent noncrystalline material. Furthermore, heterocorrelation analysis of small-angle and wideangle X-ray scattering data from the reversible crystallization regime reveals that the size of new crystals is consistent with fringedmicellar structures (~9 nm). Thus, 2D correlation analysis provides new insights into morphology development in polymeric systems.", "date": "2011-09-13", "date_type": "published", "publication": "Macromolecules", "volume": "44", "number": "17", "publisher": "American Chemical Society", "pagerange": "6836-6848", "id_number": "CaltechAUTHORS:20110929-071111864", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110929-071111864", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0505393" }, { "agency": "NSF", "grant_number": "GOALI-0523083" } ] }, "doi": "10.1021/ma200774u", "resource_type": "article", "pub_year": "2011", "author_list": "Smirnova, Diana S.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/2kq6b-2tp95", "eprint_id": 21386, "eprint_status": "archive", "datestamp": "2023-08-22 01:26:14", "lastmod": "2023-10-20 23:59:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mathias-E-V", "name": { "family": "Mathias", "given": "Errol V." } }, { "id": "Aponte-J", "name": { "family": "Aponte", "given": "Julia" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Ba-Yong", "name": { "family": "Ba", "given": "Yong" } } ] }, "title": "Properties of small molecular drug loading and diffusion in a fluorinated PEG hydrogel studied by ^1H molecular diffusion NMR and ^(19)F spin diffusion NMR", "ispublished": "pub", "full_text_status": "public", "keywords": "Fluoroalkyl double-ended poly(ethylene glycol); Hydrogel; 5-Fluorouracil; 1,3-Dimethyl-5-fluorouracil Dug delivery; Molecular diffusion; Spin diffusion; NMR", "note": "\u00a9 The Author(s) 2010. This article is published with open access at Springerlink.com.\n\nThis article is distributed under the terms of the\nCreative Commons Attribution Noncommercial License which permits\nany noncommercial use, distribution, and reproduction in any\nmedium, provided the original author(s) and source are credited.\n\nReceived: 8 June 2010; Revised: 19 September 2010; Accepted: 20 September 2010; Published online: 5 October 2010.\n\nThis research was supported by the NSF Grant\n0351848 and NSF Grant 0619147 for an NMR facility upgrade at\nCSULA.\n\nPublished - Mathias2010p12132Colloid_Polym_Sci.pdf
", "abstract": "R_f-PEG (fluoroalkyl double-ended poly(ethylene glycol)) hydrogel is potentially useful as a drug delivery depot due to its advanced properties of sol\u2013gel two-phase coexistence and low surface erosion. In this study, ^1H molecular diffusion nuclear magnetic resonance (NMR) and ^(19)F spin diffusion NMR were used to probe the drug loading and diffusion properties of the R_f-PEG hydrogel for small anticancer drugs, 5-fluorouracil (FU) and its hydrophobic analog, 1,3-dimethyl-5-fluorouracil (DMFU). It was found that FU has a larger apparent diffusion coefficient than that of DMFU, and the diffusion of the latter was more hindered. The result of ^(19)F spin diffusion NMR for the corresponding freeze-dried samples indicates that a larger portion of DMFU resided in the R_f core/IPDU intermediate-layer region (where IPDU refers to isophorone diurethane, as a linker to interconnect the R_f group and the PEG chain) than that of FU while the opposite is true in the PEG\u2013water phase. To understand the experimental data, a diffusion model was proposed to include: (1) hindered diffusion of the drug molecules in the R_f core/IPDU-intermediate-layer region; (2) relatively free diffusion of the drug molecules in the PEG-water phase (or region); and (3) diffusive exchange of the probe molecules between the above two regions. This study also shows that molecular diffusion NMR combined with spin diffusion NMR is useful in studying the drug loading and diffusion properties in hydrogels for the purpose of drug delivery applications.", "date": "2010-12", "date_type": "published", "publication": "Colloid and Polymer Science", "volume": "288", "number": "18", "publisher": "Springer", "pagerange": "1655-1663", "id_number": "CaltechAUTHORS:20101215-145930575", "issn": "0303-402X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101215-145930575", "rights": "This article is distributed under the terms of the\nCreative Commons Attribution Noncommercial License which permits\nany noncommercial use, distribution, and reproduction in any\nmedium, provided the original author(s) and source are credited.", "funders": { "items": [ { "agency": "NSF", "grant_number": "0351848" }, { "agency": "NSF", "grant_number": "0619147" } ] }, "doi": "10.1007/s00396-010-2304-9", "primary_object": { "basename": "Mathias2010p12132Colloid_Polym_Sci.pdf", "url": "https://authors.library.caltech.edu/records/2kq6b-2tp95/files/Mathias2010p12132Colloid_Polym_Sci.pdf" }, "resource_type": "article", "pub_year": "2010", "author_list": "Mathias, Errol V.; Aponte, Julia; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/hsvek-j2q17", "eprint_id": 104627, "eprint_status": "archive", "datestamp": "2023-08-19 04:40:17", "lastmod": "2023-10-20 20:40:45", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mathias-E-V", "name": { "family": "Mathias", "given": "Errol V." } }, { "id": "Aponte-J", "name": { "family": "Aponte", "given": "Julia" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Ba-Yong", "name": { "family": "Ba", "given": "Yong" } } ] }, "title": "Properties of small molecular drug loading and diffusion in a fluorinated PEG hydrogel studied by \u00b9H molecular diffusion NMR and \u00b9\u2079F spin diffusion NMR", "ispublished": "pub", "full_text_status": "public", "keywords": "Fluoroalkyl double-ended poly(ethylene glycol), Hydrogel, 5-Fluorouracil, 1,3-Dimethyl-5-fluorouracil, Dug delivery, Molecular diffusion, Spin diffusion, NMR", "note": "\u00a9 The Author(s) 2010. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. \n\nReceived: 8 June 2010; Revised: 19 September 2010; Accepted: 20 September 2010; Published online: 5 October 2010. \n\nThis research was supported by the NSF Grant 0351848 and NSF Grant 0619147 for an NMR facility upgrade at CSULA.\n\nPublished - Mathias2010_Article_PropertiesOfSmallMolecularDrug.pdf
", "abstract": "R_f-PEG (fluoroalkyl double-ended poly(ethylene glycol)) hydrogel is potentially useful as a drug delivery depot due to its advanced properties of sol\u2013gel two-phase coexistence and low surface erosion. In this study, \u00b9H molecular diffusion nuclear magnetic resonance (NMR) and \u00b9\u2079F spin diffusion NMR were used to probe the drug loading and diffusion properties of the R_f-PEG hydrogel for small anticancer drugs, 5-fluorouracil (FU) and its hydrophobic analog, 1,3-dimethyl-5-fluorouracil (DMFU). It was found that FU has a larger apparent diffusion coefficient than that of DMFU, and the diffusion of the latter was more hindered. The result of \u00b9\u2079F spin diffusion NMR for the corresponding freeze-dried samples indicates that a larger portion of DMFU resided in the R_f core/IPDU intermediate-layer region (where IPDU refers to isophorone diurethane, as a linker to interconnect the R_f group and the PEG chain) than that of FU while the opposite is true in the PEG\u2013water phase. To understand the experimental data, a diffusion model was proposed to include: (1) hindered diffusion of the drug molecules in the R_f core/IPDU-intermediate-layer region; (2) relatively free diffusion of the drug molecules in the PEG-water phase (or region); and (3) diffusive exchange of the probe molecules between the above two regions. This study also shows that molecular diffusion NMR combined with spin diffusion NMR is useful in studying the drug loading and diffusion properties in hydrogels for the purpose of drug delivery applications.", "date": "2010-12", "date_type": "published", "publication": "Colloid and Polymer Science", "volume": "288", "number": "18", "publisher": "Springer", "pagerange": "1655-1663", "id_number": "CaltechAUTHORS:20200728-174942361", "issn": "0303-402X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200728-174942361", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0351848" }, { "agency": "NSF", "grant_number": "CHE-0619147" } ] }, "doi": "10.1007/s00396-010-2304-9", "primary_object": { "basename": "Mathias2010_Article_PropertiesOfSmallMolecularDrug.pdf", "url": "https://authors.library.caltech.edu/records/hsvek-j2q17/files/Mathias2010_Article_PropertiesOfSmallMolecularDrug.pdf" }, "resource_type": "article", "pub_year": "2010", "author_list": "Mathias, Errol V.; Aponte, Julia; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/w3v38-xkq09", "eprint_id": 21204, "eprint_status": "archive", "datestamp": "2023-08-19 04:23:26", "lastmod": "2023-10-20 23:50:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Olsen-B-D", "name": { "family": "Olsen", "given": "Bradley D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Yielding Behavior in Injectable Hydrogels from Telechelic Proteins", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2010 American Chemical Society. \n\nReceived June 28, 2010; Revised Manuscript Received September 27, 2010. Published on Web 10/13/2010. \n\nThis work was supported by the NSF Center for the Science and Engineering of Materials and NIH Grant EB1971. B.D.O. was supported by Award F32GM0834 from the National Institute of General Medical Sciences and by a Beckman Institute Postdoctoral Fellowship. We thank Professor S. E. Fraser for suggesting the method of flow visualization reported in Figure 3.\n\nAccepted Version - nihms245292.pdf
Supplemental Material - ma101434a_si_001.pdf
", "abstract": "Injectable hydrogels show substantial promise for use in minimally invasive tissue engineering and drug delivery procedures. A new injectable hydrogel material, developed from recombinant telechelic proteins expressed in E. coli, demonstrates shear thinning by 3 orders of magnitude at large strains. Large-amplitude oscillatory shear illustrates that shear thinning is due to yielding within the bulk of the gel, and the rheological response and flow profiles are consistent with a shear-banding mechanism for yielding. The sharp yielding transition and large magnitude of the apparent shear thinning allow gels to be injected through narrow gauge needles with only gentle hand pressure. After injection the gels reset to full elastic strength in seconds due to rapid re-formation of the physical network junctions, allowing self-supporting structures to be formed. The shear thinning and recovery behavior is largely independent of the midblock length, enabling genetic engineering to be used to control the equilibrium modulus of the gel without loss of the characteristic yielding behavior. The shear-banding mechanism localizes deformation during flow into narrow regions of the gels, allowing more than 95% of seeded cells to survive the injection process.", "date": "2010-11-09", "date_type": "published", "publication": "Macromolecules", "volume": "43", "number": "21", "publisher": "American Chemical Society", "pagerange": "9094-9099", "id_number": "CaltechAUTHORS:20101207-081608961", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101207-081608961", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "NIH", "grant_number": "EB1971" }, { "agency": "NIH Postdoctoral Fellowship", "grant_number": "F32GM0834" }, { "agency": "Caltech Beckman Institute" } ] }, "doi": "10.1021/ma101434a", "pmcid": "PMC3017468", "primary_object": { "basename": "ma101434a_si_001.pdf", "url": "https://authors.library.caltech.edu/records/w3v38-xkq09/files/ma101434a_si_001.pdf" }, "related_objects": [ { "basename": "nihms245292.pdf", "url": "https://authors.library.caltech.edu/records/w3v38-xkq09/files/nihms245292.pdf" } ], "resource_type": "article", "pub_year": "2010", "author_list": "Olsen, Bradley D.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4crpd-wpt41", "eprint_id": 18616, "eprint_status": "archive", "datestamp": "2023-08-19 02:38:56", "lastmod": "2023-10-20 16:35:53", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mattson-M-S", "name": { "family": "Mattson", "given": "Matthew S." } }, { "id": "Huynh-Joyce", "name": { "family": "Huynh", "given": "Joyce" } }, { "id": "Wiseman-M", "name": { "family": "Wiseman", "given": "Meredith" } }, { "id": "Coassin-M", "name": { "family": "Coassin", "given": "Marco" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Schwartz-D-M", "name": { "family": "Schwartz", "given": "Daniel M." } } ] }, "title": "An In Vitro Intact Globe Expansion Method for Evaluation of Cross-linking Treatments", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2010 Association for Research in Vision and Ophthalmology. \n\nSubmitted for publication May 18, 2009; revised October 6, 2009; accepted December 15, 2009. \n\nSupported by That Man May See; National Institutes of Health Grant EY017484-01; the Jacobs Institute for Molecular Engineering for Medicine; and Caltech SURF (Summer Undergraduate Research Fellowship)\n\nPublished - Mattson2010p10206Invest_Ophth_Vis_Sci.pdf
", "abstract": "Purpose. To measure the tissue mechanical response to elevated\nintraocular pressure (IOP) using intact globe expansion\nof rabbit eyes. This method examined rabbit kit (2\u20133 weeks\nold) eyes as a model for weakened tissue and evaluated riboflavin/\nUVA and glyceraldehyde cross-linking treatments.\nMethods. The ocular shape of enucleated eyes was photographed\nduring a 24-hour period while a controlled IOP was\nimposed (either low IOP 22 mm Hg or high IOP 85 mm\nHg). Untreated controls consisted of kit eyes tested at both\nlow- and high IOP and adult eyes tested at high IOP. Treated kit\neyes (dextran controls, riboflavin/UVA treatment of the cornea,\nand glyceraldehyde treatment of the entire globe) were tested\nat high IOP.\nResults. Low IOP elicited negligible creep of the sclera and\nvery gradual creep of the cornea. In contrast, high IOP induced\nup to an 8% strain in the sclera and a 15% strain in the cornea\nof rabbit kit eyes. The expansion of adult eyes was less than\none third that of kit eyes at the same, high IOP. Riboflavin/UVA\ntreatment of corneas reduced expansion compared with that in\nboth dextran-treated and untreated control corneas. Glyceraldehyde\ntreatment prevented expansion of the cornea and\nsclera.\nConclusions. The intact globe expansion method (GEM) imposes\na loading geometry comparable to in vivo conditions and\ncan quantify changes in mechanical stability as a function of\ntesting conditions (e.g., IOP, tissue maturation, and therapeutic\ncross-linking) with small sample sizes and small variability.\nRabbit kit eyes provide a model of weak tissue suitable for\nscreening treatments that strengthen the cornea and sclera.", "date": "2010-06", "date_type": "published", "publication": "Investigative Ophthalmology and Visual Science", "volume": "51", "number": "6", "publisher": "Lippincott, Williams & Wilkins", "pagerange": "3120-3128", "id_number": "CaltechAUTHORS:20100609-094136042", "issn": "0146-0404", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100609-094136042", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "EY017484-01" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "That Man May See Foundation" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.1167/iovs.09-4001", "pmcid": "PMC2891471", "primary_object": { "basename": "Mattson2010p10206Invest_Ophth_Vis_Sci.pdf", "url": "https://authors.library.caltech.edu/records/4crpd-wpt41/files/Mattson2010p10206Invest_Ophth_Vis_Sci.pdf" }, "resource_type": "article", "pub_year": "2010", "author_list": "Mattson, Matthew S.; Huynh, Joyce; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6pwqh-kyq38", "eprint_id": 18331, "eprint_status": "archive", "datestamp": "2023-08-19 00:57:28", "lastmod": "2023-10-20 16:07:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Dong-Yul", "name": { "family": "Lee", "given": "Dong-Yul" } }, { "id": "Seo-Jung-Min", "name": { "family": "Seo", "given": "Jung-Min" } }, { "id": "Khan-Waliullah", "name": { "family": "Khan", "given": "Waliullah" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kurji-Zuleikha", "name": { "family": "Kurji", "given": "Zuleikha" } }, { "id": "Park-Soo-Young", "name": { "family": "Park", "given": "Soo-Young" } } ] }, "title": "pH-responsive aqueous/LC interfaces using SGLCP-b-polyacrylic acid block copolymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2010 The Royal Society of Chemistry.\nReceived 15th December 2009, Accepted 22nd February 2010.\nFirst published as an Advance Article on the web 26th March 2010.\n\nPublished - Lee2010p9955Soft_Matter.pdf
Supplemental Material - b926461b.mpg
Supplemental Material - b926461b.pdf
", "abstract": "Block copolymers that combine a side-group liquid crystalline polymer (SGLCP) block and\na pH-responsivehydrophilic block, poly(acrylic acid) (PAA), are shown to confer pH-dependent anchoring of the director orientation at the aqueous/LC interface. The SGLCP block, poly(4-cyanobiphenyl-4-oxyundecylacrylate), was chosen based on its ability to influence the director field of the 5CB (4-cyano-4'-pentylbiphenyl). At low pH the PAA block collapses and the inherent, planar alignment tendency of 5CB at a water interface prevails. As pH increases, the polyelectrolyte block becomes increasingly charged and expands, producing a change to homeotropic anchoring. The change in anchoring occurs as quickly as the buffer can be changed (within ~2 s) and is reversible, with a response that is repeatable over as many cycles as were tested (approximately 20 cycles). The polymer-mediated anchoring persists for 6 days, indicating that the SGLCP block secures the self-assembled layer on the 5CB, even under conditions that cause repulsive interactions among the PAA blocks. Thus, SGLCP blocks can translate conformational changes of a responsive hydrophilic block into rapid, reversible changes in the director field", "date": "2010", "date_type": "published", "publication": "Soft Matter", "volume": "6", "number": "9", "publisher": "Royal Society of Chemistry", "pagerange": "1964-1970", "id_number": "CaltechAUTHORS:20100517-153103244", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100517-153103244", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "collection": "CaltechAUTHORS", "doi": "10.1039/b926461b", "primary_object": { "basename": "Lee2010p9955Soft_Matter.pdf", "url": "https://authors.library.caltech.edu/records/6pwqh-kyq38/files/Lee2010p9955Soft_Matter.pdf" }, "related_objects": [ { "basename": "b926461b.mpg", "url": "https://authors.library.caltech.edu/records/6pwqh-kyq38/files/b926461b.mpg" }, { "basename": "b926461b.pdf", "url": "https://authors.library.caltech.edu/records/6pwqh-kyq38/files/b926461b.pdf" } ], "resource_type": "article", "pub_year": "2010", "author_list": "Lee, Dong-Yul; Seo, Jung-Min; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0342e-h8p61", "eprint_id": 17432, "eprint_status": "archive", "datestamp": "2023-08-19 00:56:00", "lastmod": "2023-10-19 23:53:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "Olsen-B-D", "name": { "family": "Olsen", "given": "Bradley D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Efficient Synthesis of Narrowly Dispersed Brush Copolymers and Study of Their Assemblies: The Importance of Side Chain Arrangement", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2009 American Chemical Society. \n\nReceived October 2, 2009. Publication Date (Web): November 30, 2009. \n\nThis work was supported by the Department of Energy (DE-FG02-05ER46218). We gratefully acknowledge Professor James R. Heath for the use of the AFM, Brookhaven National Lab for the use of SAXS, Lixia Rong for assistance with SAXS measurement, and Edward H. Bramston-Cook for assistance with AFM measurement. BDO thanks the Caltech Beckman Institute for a postdoctoral fellowship.\n\nSupplemental Material - ja908379q_si_001.pdf
", "abstract": "Efficient, one-pot preparation of synthetically challenging, high molecular weight (MW), narrowly dispersed brush block copolymers and random copolymers in high conversions was achieved by ring-opening metathesis (co)polymerization (ROMP) of various macromonomers (MMs) using the highly active, fast-initiating ruthenium olefin metathesis catalyst (H_2IMes)(pyr)_2(Cl)_2RuCHPh. A series of random and block copolymers were prepared from a pair of MMs containing polylactide (PLA) and poly(n-butyl acrylate) (PnBA) side chains at similar MWs. Their self-assembly in the melt state was studied by small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). In brush random copolymers containing approximately equal volume fractions of PLA and PnBA, the side chains segregate into lamellae with domain spacing of 14 nm as measured by SAXS, which was in good agreement with the lamellar thickness measured by AFM. The domain spacings and order\u2212disorder transition temperatures of brush random copolymers were insensitive to the backbone length. In contrast, brush block copolymers containing approximately equal volume fractions of these MMs self-assembled into highly ordered lamellae with domain spacing over 100 nm. Their assemblies suggested that the brush block copolymer backbone adopted an extended conformation in the ordered state.", "date": "2009-12-30", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "131", "number": "51", "publisher": "American Chemical Society", "pagerange": "18525-18532", "id_number": "CaltechAUTHORS:20100209-102313120", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100209-102313120", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-05ER46218" }, { "agency": "Caltech Beckman Institute" } ] }, "doi": "10.1021/ja908379q", "primary_object": { "basename": "ja908379q_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0342e-h8p61/files/ja908379q_si_001.pdf" }, "resource_type": "article", "pub_year": "2009", "author_list": "Xia, Yan; Olsen, Bradley D.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4q9m4-d5b94", "eprint_id": 17194, "eprint_status": "archive", "datestamp": "2023-08-21 22:54:06", "lastmod": "2023-10-19 23:38:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "David-R-L-A", "name": { "family": "David", "given": "R. L. Ameri" } }, { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Effects of pairwise, donor-acceptor functional groups on polymer solubility, solution viscosity and mist control", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Donor-acceptor interactions; Extensional rheology; Mist control", "note": "\u00a9 2009 Published by Elsevier Ltd. Received 19 June 2009; \nrevised 29 September 2009; \naccepted 3 October 2009. \nAvailable online 16 October 2009.\nFunding for this research was provided by the FAA and NASA,\nthe Caltech Milliken Foundation, and the Caltech Gates Grubstake\nFund. We acknowledge the contributions of Brett F. Bathel and Prof.\nAlbert Ratner (University of Iowa) in the drop breakup experiments\nand of Dr. Jan P. Plog (Thermo Fisher Scientific) in the CaBER\nexperiments. We also thank Dr. Steven Smith of Proctor and Gamble\nCompany for supplying the 1,2-PB precursor materials, and Dr.\nSuneel Kunamaneni for contributing the ideas that initiated the\ndirection of this work.", "abstract": "Homologous series of functionalized polymers were used to compare the solution properties of donor\u2013acceptor (DA) interpolymer mixtures with those of self-associating and non-associating polymer analogues. Polymer analogous synthesis was used to produce a series of polymers from a specific, anionically-polymerized prepolymer (1250 kg/mol polybutadiene), using thiol-ene coupling to incorporate systematically-varied contents of side groups: either tertiary amines (as proton acceptors) or carboxylic acids (both as proton donors in donor\u2013acceptor mixtures, or as self-associating moieties in single-polymer solutions). Comparison with controls reveals that, relative to the effects of self-associations, DA interpolymer interactions more strongly affect solution properties such as phase behavior, interpolymer aggregation, shear viscosity, and elastic response in extensional flow. Specifically, DA associations lead to (i) greater reductions in polymer solubility in hydrocarbon solvents, (ii) interpolymer aggregation into larger clusters, and (iii) greater shear viscosity in solution. Nevertheless, DA associations reduced solution elasticity and mist suppression\u2014a highly unanticipated result in light of the prior literature.", "date": "2009-12-10", "date_type": "published", "publication": "Polymer", "volume": "50", "number": "26", "publisher": "Elsevier", "pagerange": "6323-6330", "id_number": "CaltechAUTHORS:20100114-153329967", "issn": "0032-3861", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100114-153329967", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "FAA" }, { "agency": "NASA" }, { "agency": "Caltech Milliken Foundation" }, { "agency": "Caltech Gates Grubstake Fund" } ] }, "doi": "10.1016/j.polymer.2009.10.032", "resource_type": "article", "pub_year": "2009", "author_list": "David, R. L. Ameri; Wei, Ming-Hsin; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/12yvr-xnq57", "eprint_id": 16455, "eprint_status": "archive", "datestamp": "2023-08-18 23:56:13", "lastmod": "2023-10-19 22:15:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Fernandez-Ballester-L", "name": { "family": "Fernandez-Ballester", "given": "Lucia" } }, { "id": "Thurman-D-W", "name": { "family": "Thurman", "given": "Derek W." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Real-time depth sectioning: Isolating the effect of stress on structure development in pressure-driven flow", "ispublished": "pub", "full_text_status": "public", "keywords": "channel flow, crystallisation, polymer blends, rheology, shear strength, X-ray scattering", "note": "\u00a92009 The Society of Rheology. \n\nReceived 24 February 2009; revised 10 June 2009. \n\nFinancial support for this work was provided by the National Science Foundation under Grant Nos. DMR-0505393 and DMI-0218112, and by the ARCS Foundation. We are grateful to Dr. Weijun Zhou and Dr. R. L. Sammler of Dow Chemical Co. for kindly providing the materials used in this study. We thank Jan Willem Housmans for microfocus measurements, and Lixia Rong and Igors Sics for help with experimental setup at X27C (NSLS). We acknowledge NSLS and ESRF for providing beamtime and facilities.\n\nPublished - FernandezBallester2009p6106J_Rheol.pdf
", "abstract": "Transient structure development at a specific distance from the channel wall in a pressure-driven flow is obtained from a set of real-time measurements that integrate contributions throughout the thickness of a rectangular channel. This \"depth sectioning method\" retains the advantages of pressure-driven flow while revealing flow-induced structures as a function of stress. The method is illustrated by applying it to isothermal shear-induced crystallization of an isotactic polypropylene using both synchrotron x-ray scattering and optical retardance. Real-time, depth-resolved information about the development of oriented precursors reveals features that cannot be extracted from ex-situ observation of the final morphology and that are obscured in the depth-averaged in-situ measurements. For example, at 137 \u00b0C and at the highest shear stress examined (65 kPa), oriented thread-like nuclei formed rapidly, saturated within the first 7 s of flow, developed significant crystalline overgrowth during flow and did not relax after cessation of shear. At lower stresses, threads formed later and increased at a slower rate. The depth sectioning method can be applied to the flow-induced structure development in diverse complex fluids, including block copolymers, colloidal systems, and liquid-crystalline polymers.", "date": "2009-09", "date_type": "published", "publication": "Journal of Rheology", "volume": "53", "number": "5", "publisher": "Society of Rheology", "pagerange": "1229-1254", "id_number": "CaltechAUTHORS:20091022-125318589", "issn": "0148-6055", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091022-125318589", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0505393" }, { "agency": "NSF", "grant_number": "DMI-0218112" }, { "agency": "Arcs Foundation" } ] }, "doi": "10.1122/1.3164970", "primary_object": { "basename": "FernandezBallester2009p6106J_Rheol.pdf", "url": "https://authors.library.caltech.edu/records/12yvr-xnq57/files/FernandezBallester2009p6106J_Rheol.pdf" }, "resource_type": "article", "pub_year": "2009", "author_list": "Fernandez-Ballester, Lucia; Thurman, Derek W.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/v2be1-fmf47", "eprint_id": 15589, "eprint_status": "archive", "datestamp": "2023-08-20 02:01:21", "lastmod": "2023-10-19 14:36:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Efficient Synthesis of Narrowly Dispersed Brush Polymers via Living Ring-Opening Metathesis Polymerization of Macromonomers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2009 American Chemical Society. \n\nReceived February 6, 2009; Revised Manuscript Received March 19, 2009. Publication Date (Web): April 20, 2009. \n\nThis work was supported by the Department of Energy (DE-FG02-05ER46218) and the National Science Foundation (CHE-0410425). We gratefully acknowledge Dr. Bradley D. Olsen and Peigen Cao for helpful discussions about the AFM, and Professor James R. Heath for the use of the AFM. \n\nSupporting Information: Additional GPC traces of prepolymers, macromonomers, and brush polymers, 1H NMR spectra of brush polymers, and AFM cross-sectional analysis of brush polymer. This material is available free of charge via the Internet at http://pubs.acs.org.\n\nSupplemental Material - Xiama900280c_si_001.pdf
", "abstract": "Various macromonomers (MMs) were efficiently synthesized through the copper-catalyzed \"click\" coupling of a norbornene moiety to the chain end of poly(methylacrylate), poly(t-butylacrylate), and polystyrene that were prepared using atom transfer radical polymerization. Ring-opening metathesis polymerization (ROMP) of these MMs was carried out using the highly active, fast-initiating ruthenium catalyst (H_2IMes)(pyr)_2(Cl)_2RuCHPh in THF at room temperature. ROMP of MMs was found to be living with almost quantitative conversions (>90%) of MMs, producing brush polymers with very low polydispersity indices of 1.01\u22121.07 and high Mn's of 200\u22122600 kDa. The efficient ROMP of such MMs provides facile access to a variety of brush polymers and overcomes previous difficulties in the controlled polymerization of MMs. Atomic force microscopy of the brush polymer products revealed extended, wormlike shapes as a result of significant steric repulsion of densely grafted side chains.", "date": "2009-06-09", "date_type": "published", "publication": "Macromolecules", "volume": "42", "number": "11", "publisher": "American Chemical Society", "pagerange": "3761-3766", "id_number": "CaltechAUTHORS:20090903-150642857", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090903-150642857", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-05ER46218" }, { "agency": "NSF", "grant_number": "CHE-0410425" } ] }, "doi": "10.1021/ma900280c", "primary_object": { "basename": "Xiama900280c_si_001.pdf", "url": "https://authors.library.caltech.edu/records/v2be1-fmf47/files/Xiama900280c_si_001.pdf" }, "resource_type": "article", "pub_year": "2009", "author_list": "Xia, Yan; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/2p6qz-wrj51", "eprint_id": 15550, "eprint_status": "archive", "datestamp": "2023-08-20 01:00:41", "lastmod": "2023-10-19 14:33:47", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "Boydston-A-J", "name": { "family": "Boydston", "given": "Andrew J." } }, { "id": "Yao-Yefeng", "name": { "family": "Yao", "given": "Yefeng" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Gorodetskaya-I-A", "name": { "family": "Gorodetskaya", "given": "Irina A." } }, { "id": "Spiess-H-W", "name": { "family": "Spiess", "given": "Hans W." } }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Ring-Expansion Metathesis Polymerization: Catalyst-Dependent Polymerization Profiles", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2009 American Chemical Society. \n\nReceived October 25, 2008. Publication Date (Web): January 29, 2009. \n\nSupporting Information Available: Kinetic plot of catalyst initiation studies, Mw versus time for REMP of COE, GPC traces of REMP of COE and COE macrocycles, and 1H NMR spectrum of COE macrocycles. This material is available free of charge via the Internet at http://pubs.acs.org. \n\nThis work was supported by the Department of Energy (DE-FG02-05ER46218). We gratefully acknowledge Materia, Inc. for the generous gift of catalyst 1. A.J.B. thanks the NIH/NCI for a postdoctoral fellowship. We thank Professor Manfred Wilhelm and Dr. Robert Graf for help with the melt-state 13C NMR spectroscopy, Professor Gregory B. McKenna for helpful discussions, Matthew M. Van Wingerden and Dr. Nathan F. Dalleska for help with ICP-MS, and John B. Matson and Ron Walker for maintaining the GPC.\n\nAccepted Version - nihms-91949.pdf
Supplemental Material - Xia2009p1659J_Am_Chem_Soc_supp.pdf
", "abstract": "Ring-expansion metathesis polymerization (REMP) mediated by recently developed cyclic Ru catalysts has been studied in detail with a focus on the polymer products obtained under varied reaction conditions and catalyst architectures. Depending upon the nature of the catalyst structure, two distinct molecular weight evolutions were observed. Polymerization conducted with catalysts bearing six-carbon tethers displayed rapid polymer molecular weight growth which reached a maximum value at ca. 70% monomer conversion, resembling a chain-growth polymerization mechanism. In contrast, five-carbon-tethered catalysts led to molecular weight growth that resembled a step-growth mechanism with a steep increase occurring only after 95% monomer conversion. The underlying reason for these mechanistic differences appeared to be ready release of five-carbon-tethered catalysts from growing polymer rings, which competed significantly with propagation. Owing to reversible chain transfer and the lack of end groups in REMP, the final molecular weights of cyclic polymers was controlled by thermodynamic equilibria. Large ring sizes in the range of 60\u2212120 kDa were observed at equilibrium for polycyclooctene and polycyclododecatriene, which were found to be independent of catalyst structure and initial monomer/catalyst ratio. While six-carbon-tethered catalysts were slowly incorporated into the formed cyclic polymer, the incorporation of five-carbon-tethered catalysts was minimal, as revealed by ICP-MS. Further polymer analysis was conducted using melt-state magic-angle spinning ^(13)C NMR spectroscopy of both linear and cyclic polymers, which revealed little or no chain ends for the latter topology.", "date": "2009-02-25", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "131", "number": "7", "publisher": "American Chemical Society", "pagerange": "2670-2677", "id_number": "CaltechAUTHORS:20090902-085242708", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090902-085242708", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-05ER46218" }, { "agency": "NIH" } ] }, "doi": "10.1021/ja808296a", "pmcid": "PMC2658644", "primary_object": { "basename": "Xia2009p1659J_Am_Chem_Soc_supp.pdf", "url": "https://authors.library.caltech.edu/records/2p6qz-wrj51/files/Xia2009p1659J_Am_Chem_Soc_supp.pdf" }, "related_objects": [ { "basename": "nihms-91949.pdf", "url": "https://authors.library.caltech.edu/records/2p6qz-wrj51/files/nihms-91949.pdf" } ], "resource_type": "article", "pub_year": "2009", "author_list": "Xia, Yan; Boydston, Andrew J.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/cgp3k-22v96", "eprint_id": 14130, "eprint_status": "archive", "datestamp": "2023-08-20 00:51:49", "lastmod": "2023-10-18 16:08:54", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "David-R-L-A", "name": { "family": "David", "given": "R. L. Ameri" } }, { "id": "Wei-Ming-Hsin", "name": { "family": "Wei", "given": "Ming-Hsin" } }, { "id": "Liu-David", "name": { "family": "Liu", "given": "David" } }, { "id": "Bathel-B-F", "name": { "family": "Bathel", "given": "Brett F." } }, { "id": "Plog-J-P", "name": { "family": "Plog", "given": "Jan P." } }, { "id": "Ratner-A", "name": { "family": "Ratner", "given": "Albert" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Effects of pairwise, self-associating functional side groups on polymer solubility, solution viscosity, and mist control", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2009 American Chemical Society.\nReceived September 9, 2008; revised manuscript received December 15, 2008. Publication Date (Web): February 3, 2009. \nFunding for this research was provided by the FAA and NASA, the Caltech Milliken Foundation, and the Caltech Gates Grubstake Fund. We thank Dr. Steven Smith of Procter and Gamble Company for supplying the 1,2-PB precursor materials and Dr. Suneel Kunamaneni for contributing the ideas that initiated the direction of this work.\nSupporting Information Available: Method for the determination of the acid content of functionalized polymer; extensional viscosity results of select solutions; numerical approach for the study of the chain statistics of self-associating chains at infinite dilution in \u0398-solvent. This material is available free of charge via the Internet at http://pubs.acs.org.\n\nSupplemental Material - ma802058s_si_001.pdf
", "abstract": "Solution properties are reported for homologous series of narrowly distributed polymers with systematically varied content of self-associating groups. Anionically polymerized polybutadienes of two lengths (510 and 1250 kg/mol) serve as prepolymers that are modified by incorporation of carboxylic acid side groups using thiol\u2212ene coupling to pendant vinyl groups. Carboxylic acid groups strongly reduce polymer solubility in hydrocarbon solvents, restricting the extent of functionalization that can be examined in single-phase solutions (e.g., in chlorododecane, functionalization must be kept <1.8 mol % even for the shorter of the two backbones). In the single-phase regime, addition of hydrogen bond \"stickers\" weakly affects solution viscosity. Even at concentrations that produce overlap at the scale of strand length between stickers, viscosity increases are less than 1 order of magnitude. These controlled studies (using functionalized and unmodified polymer homologues of matched, well-defined length) challenge the pre-existing understanding of the rheology of self-associating polymers. The results indicate that effects of intrachain pairing are important beyond the dilute regimebehavior unaccounted for in earlier experimental and theoretical studies. The implications for mist control of aviation fuel are that self-associating polymers of acceptable solubility in the fuel are not superior to nonassociating polymers even at concentrations several times above overlap.", "date": "2009-02-03", "date_type": "published", "publication": "Macromolecules", "volume": "42", "number": "4", "publisher": "American Chemical Society", "pagerange": "1380-1391", "id_number": "CaltechAUTHORS:20090501-105915785", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090501-105915785", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "FAA" }, { "agency": "NASA" }, { "agency": "Caltech Milliken Foundation" }, { "agency": "Caltech Gates Grubstake Fund" } ] }, "doi": "10.1021/ma802058s", "primary_object": { "basename": "ma802058s_si_001.pdf", "url": "https://authors.library.caltech.edu/records/cgp3k-22v96/files/ma802058s_si_001.pdf" }, "resource_type": "article", "pub_year": "2009", "author_list": "David, R. L. Ameri; Wei, Ming-Hsin; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6fzt1-g9r02", "eprint_id": 13188, "eprint_status": "archive", "datestamp": "2023-08-20 00:34:31", "lastmod": "2023-10-17 22:45:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Scruggs-N-R", "name": { "family": "Scruggs", "given": "Neal R." } }, { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Uhring-D", "name": { "family": "Uhrig", "given": "David" } }, { "id": "Khan-Waliullah", "name": { "family": "Khan", "given": "Waliullah" } }, { "id": "Park-Soo-Young", "name": { "family": "Park", "given": "Soo-Young" } }, { "id": "Lal-Jyotsana", "name": { "family": "Lal", "given": "Jyotsana" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Self-Assembly of Coil/Liquid-Crystalline Diblock Copolymers in a Liquid Crystal Solvent", "ispublished": "pub", "full_text_status": "public", "note": "Copyright \u00a9 2008 American Chemical Society. \n\nReceived July 16, 2008; Revised Manuscript Received October 18, 2008. Publication Date (Web): December 5, 2008. \n\nA portion of the results shown in this report are derived from work performed at Argonne National Laboratory. Argonne is operated by UChicago Argonne, LLC, for the U.S. Department of Energy under Contract DE-AC02-06CH11357. Another portion of this work was performed at Oak Ridge National Laboratory's Center for Nanophase Materials Sciences which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. This work benefited from use of the shared facilities supported by the MRSEC Program of the National Science Foundation under Award DMR-0080065. N.R.S., R.V., and J.A.K. acknowledge financial support from the AFOSR LC-MURI (f4962-97-1-0014); S.-Y.P. and J.A.K. acknowledge financial support from MOST and AFOSR NBIT 2007 program. We thank Ed Lang and Zuleika Kurji for assistance with neutron scattering experiments. National Defense Science and Engineering Graduate Fellowships awarded to N.R.S. and R.V. are greatly appreciated. \n\nSupporting Information: Table of solution transition temperatures, results from side-on diblock copolymer solutions, and dynamic moduli of end-on diblock copolymer solutions. This material is available free of charge via the Internet at http://pubs.acs.org.\n\nSupplemental Material - SCRUm09supp.pdf
", "abstract": "Diblock copolymers having a random-coil polymer block (polystyrene, PS) connected to a side-group liquid crystal polymer (SGLCP) self-assemble in a nematic liquid crystal (LC), 4-pentyl-4\u2032-cyanobiphenyl, into micelles with PS-rich cores and SGLCP-rich coronas. The morphologies of block copolymers with varying PS content are characterized as a function of temperature and concentration using small-angle neutron scattering, rheometry, and transmission electron microscopy. Unlike conventional solvents, the nematic LC can undergo a first-order transition between distinct fluid phases, accessing the regimes of both strong and slight selectivity in a single polymer/solvent pair. Micelles dissolve away above a microphase separation temperature (MST) that is often equal to the solution's isotropization point, TNI. However, increasing or decreasing the polymer's PS content can shift the MST to be above or below TNI, respectively, and in the former case, micelles abruptly swell with solvent at TNI. Comparable effects can be achieved by modulating the overall polymer concentration.", "date": "2009-01", "date_type": "published", "publication": "Macromolecules", "volume": "42", "number": "1", "publisher": "American Chemical Society", "pagerange": "299-307", "id_number": "CaltechAUTHORS:SCRUm09", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SCRUm09", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy", "grant_number": "DE-AC02-06CH11357" }, { "agency": "Oak Ridge National Laboratory" }, { "agency": "National Science Foundation", "grant_number": "DMR-0080065" }, { "agency": "Air Force Office of Scientific Research", "grant_number": "f4962-97-1-0014" }, { "agency": "Ministry of Science and Technology (MOST) (Korea)" }, { "agency": "Department of Defense" } ] }, "doi": "10.1021/ma801598y", "primary_object": { "basename": "SCRUm09supp.pdf", "url": "https://authors.library.caltech.edu/records/6fzt1-g9r02/files/SCRUm09supp.pdf" }, "resource_type": "article", "pub_year": "2009", "author_list": "Scruggs, Neal R.; Verduzco, Rafael; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/32wjt-z8w29", "eprint_id": 11840, "eprint_status": "archive", "datestamp": "2023-08-22 13:08:03", "lastmod": "2023-10-17 15:49:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Boydston-A-J", "name": { "family": "Boydston", "given": "Andrew J." } }, { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Gorodetskaya-I-A", "name": { "family": "Gorodetskaya", "given": "Irina A." } }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Cyclic Ruthenium-Alkylidene Catalysts for Ring-Expansion Metathesis Polymerization", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2008 American Chemical Society. \n\nReceived May 27, 2008. Web Release Date: August 27, 2008. \n\nWe gratefully acknowledge Materia, Inc. for the generous gift of catalyst 1. We thank the DOE (DE-FG02-05ER46218), NIH (5RO1GM-31332), and the California Institute of Technology for generous financial support. A.J.B. thanks the NIH/NCI for a postdoctoral fellowship. We thank Professor Gregory B. McKenna for helpful discussions, as well as Matthew T. Whited, Larry M. Henling, and Dr. Michael W. Day for help in obtaining X-ray data. \n\nSupporting Information Available: Additional representations of Figure 4, NMR spectra for all new compounds, CIF files containing X-ray structural data, atomic coordinates, thermal parameters, bond distances, and bond angles for complexes 5cyc\u00b7H2, 6cyc, and 6cyc\u00b7H2. This material is available free of charge via the Internet at http://pubs.acs.org.\n\nAccepted Version - nihms86291.pdf
Supplemental Material - ja8037849-File004.pdf
Supplemental Material - ja8037849-File005.cif
Supplemental Material - ja8037849-File006.cif
Supplemental Material - ja8037849-File007.cif
Cover Image - ja-2008-037849_0012.gif
", "abstract": "A series of cyclic Ru-alkylidene catalysts have been prepared and evaluated for their efficiency in ring-expansion metathesis polymerization (REMP). The catalyst structures feature chelating tethers extending from one N-atom of an N-heterocyclic carbene (NHC) ligand to the Ru metal center. The catalyst design is modular in nature, which provided access to Ru complexes having varying tether lengths, as well as electronically different NHC ligands. Structural impacts of the tether length were unveiled through 1H NMR spectroscopy as well as single-crystal X-ray analyses. Catalyst activities were evaluated via polymerization of cyclooctene, and key data are provided regarding propagation rates, intramolecular chain transfer, and catalyst stabilities, three areas necessary for the efficient synthesis of cyclic poly(olefin)s via REMP. From these studies, it was determined that while increasing the tether length of the catalyst leads to enhanced rates of polymerization, shorter tethers were found to facilitate intramolecular chain transfer and release of catalyst from the polymer. Electronic modification of the NHC via backbone saturation was found to enhance polymerization rates to a greater extent than did homologation of the tether. Overall, cyclic Ru complexes bearing 5- or 6-carbon tethers and saturated NHC ligands were found to be readily synthesized, bench-stable, and highly active catalysts for REMP.", "date": "2008-09-24", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "130", "number": "38", "publisher": "American Chemical Society", "pagerange": "12775-12782", "id_number": "CaltechAUTHORS:BOYjacs08", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:BOYjacs08", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-05ER46218" }, { "agency": "NIH", "grant_number": "5RO1GM-31332" }, { "agency": "Caltech" }, { "agency": "National Cancer Institute" } ] }, "doi": "10.1021/ja8037849", "pmcid": "PMC2636571", "primary_object": { "basename": "medium.png", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/medium.png" }, "related_objects": [ { "basename": "nihms86291.pdf", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/nihms86291.pdf" }, { "basename": "small.png", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/small.png" }, { "basename": "ja-2008-037849_0012.gif", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/ja-2008-037849_0012.gif" }, { "basename": "ja8037849-File004.pdf", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/ja8037849-File004.pdf" }, { "basename": "ja8037849-File005.cif", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/ja8037849-File005.cif" }, { "basename": "ja8037849-File006.cif", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/ja8037849-File006.cif" }, { "basename": "ja8037849-File007.cif", "url": "https://authors.library.caltech.edu/records/32wjt-z8w29/files/ja8037849-File007.cif" } ], "resource_type": "article", "pub_year": "2008", "author_list": "Boydston, Andrew J.; Xia, Yan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/w2w4q-0f140", "eprint_id": 79296, "eprint_status": "archive", "datestamp": "2023-08-19 22:22:21", "lastmod": "2023-10-26 14:46:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Krishnaswamy-R-K", "name": { "family": "Krishnaswamy", "given": "Rajendra K." } }, { "id": "Yang-Qing", "name": { "family": "Yang", "given": "Qing" } }, { "id": "Fernandez-Ballester-L", "name": { "family": "Fernandez-Ballester", "given": "Lucia" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Effect of the Distribution of Short-Chain Branches on Crystallization Kinetics and Mechanical Properties of High-Density Polyethylene", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2008 American Chemical Society. \n\nReceived 21 February 2007. Published online 8 February 2008. Published in print 1 March 2008. \n\nThe authors would like to acknowledge useful discussions with Prof. Stephen Cheng (University of Akron) and Prof. Garth Wilkes (Virginia Tech). Dr. Paul DesLauriers and Dr. David Rohlfing are acknowledged for molecular weight and rheological characterization of the polymers and blends. The authors are also grateful to Barbara Lewis, Jim French, Jerry Stark, David Higbee, Tim Harper, and Delores Henson for performing most of the experiments. Financial support by the National Science Foundation (Grants DMI-0218112 and DMI-0523083) is acknowledged.", "abstract": "The effects of the placement of short-chain branches (SCB) on crystallization kinetics, morphology and mechanical properties of high-density polyethylene (HDPE) are examined using bimodal blends of short (S \u223c40 kg/mol) and long (L \u223c400 kg/mol and 550 kg/mol) polyethylenes with SCB (1-hexene comonomer) incorporated in either the high or the low molecular weight component. A pair of blends that has nearly matched molecular weight distribution and average SCB content shows that placement of branches preferentially on the longer molecules results in slower crystallization kinetics at high crystallization temperatures relative to the material with branches on the short chains. Blends with SCB on the high molecular weight components have superior ultimate mechanical properties, and their resistance to slow crack growth is tremendously enhanced. These improved mechanical properties are attributed to an increase in the amount of tie chains that form when branches are placed on the long chains. A conceptual model based on the interplay of inherent crystallization kinetics of each species and their competition at the growth front in binary blends qualitatively explains the effects of SCB distribution on crystallization kinetics, lamellar thickness and inferred formation of tie chains.", "date": "2008-03-11", "date_type": "published", "publication": "Macromolecules", "volume": "41", "number": "5", "publisher": "American Chemical Society", "pagerange": "1693-1704", "id_number": "CaltechAUTHORS:20170724-102215381", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-102215381", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMI-0218112" }, { "agency": "NSF", "grant_number": "DMI-0523083" } ] }, "doi": "10.1021/ma070454h", "resource_type": "article", "pub_year": "2008", "author_list": "Krishnaswamy, Rajendra K.; Yang, Qing; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/2n9dm-src64", "eprint_id": 70300, "eprint_status": "archive", "datestamp": "2023-08-22 11:15:52", "lastmod": "2023-10-20 22:07:59", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Fernandez-Ballester-L", "name": { "family": "Fernandez-Ballester", "given": "Lucia" } }, { "id": "Gough-T", "name": { "family": "Gough", "given": "Tim" } }, { "id": "Meneau-F", "name": { "family": "Meneau", "given": "Florian" } }, { "id": "Bras-Wim", "name": { "family": "Bras", "given": "Wim" } }, { "id": "Ania-F", "name": { "family": "Ania", "given": "Fernando" } }, { "id": "Balta-Calleja-F-J", "name": { "family": "Balta-Calleja", "given": "Francisco Jose" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Simultaneous birefringence, small- and wide-angle X-ray scattering to detect precursors and characterize morphology development during flow-induced crystallization of polymers", "ispublished": "pub", "full_text_status": "public", "keywords": "simultaneous; optical; SAXS; WAXD; flow-induced crystallization; polymer; birefringence", "note": "\u00a9 2008 International Union of Crystallography. \n\nReceived 30 April 2007; Accepted 23 January 2008. \n\nThis work was funded by the National Science Foundation under awards DMR-0080065 and DMR-0505393. The authors are grateful to Dr Jan Verhoeven (Amolf) for providing the Al-coated mica mirrors. We acknowledge the European Synchrotron Radiation Facility and the Netherlands Organization for Scientific Research for provision of synchrotron radiation facilities, and all DUBBLE staff for assistance during experiments. Mr B. Vrolijk of Element 6 is thanked for advice on how to mount the diamond windows. FA and FJBC wish to acknowledge the 'Ministerio de Educaci\u00f3n y Ciencia' (grant FIS2004-01331), Spain, for financial support. LFB wishes to acknowledge the 'la Caixa' fellowship program.\n\nPublished - S0909049508002598.pdf
", "abstract": "An experimental configuration that combines the powerful capabilities of a short-term shearing apparatus with simultaneous optical and X-ray scattering techniques is demonstrated, connecting the earliest events that occur during shear-induced crystallization of a polymer melt with the subsequent kinetics and morphology development. Oriented precursors are at the heart of the great effects that flow can produce on polymer crystallization (strongly enhanced kinetics and formation of highly oriented crystallites), and their creation is highly dependent on material properties and the level of stress applied. The sensitivity of rheo-optics enables the detection of these dilute shear-induced precursors as they form during flow, before X-ray techniques are able to reveal them. Then, as crystallization occurs from these precursors, X-ray scattering allows detailed quantification of the characteristics and kinetics of growth of the crystallites nucleated by the flow-induced precursors. This simultaneous combination of techniques allows unambiguous correlation between the early events that occur during shear and the evolution of crystallization after flow has stopped, eliminating uncertainties that result from the extreme sensitivity of flow-induced crystallization to small changes in the imposed stress and the material. Experimental data on a bimodal blend of isotactic polypropylenes are presented.", "date": "2008-03", "date_type": "published", "publication": "Journal of Synchrotron Radiation", "volume": "15", "number": "2", "publisher": "International Union of Crystallography", "pagerange": "185-190", "id_number": "CaltechAUTHORS:20160913-100354709", "issn": "0909-0495", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160913-100354709", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0080065" }, { "agency": "NSF", "grant_number": "DMR-0505393" }, { "agency": "Ministerio de Educaci\u00f3n y Ciencia (MEC)", "grant_number": "FIS2004-01331" }, { "agency": "La Caixa Fellowship" } ] }, "doi": "10.1107/S0909049508002598", "primary_object": { "basename": "S0909049508002598.pdf", "url": "https://authors.library.caltech.edu/records/2n9dm-src64/files/S0909049508002598.pdf" }, "resource_type": "article", "pub_year": "2008", "author_list": "Fernandez-Ballester, Lucia; Gough, Tim; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/74c1x-9zg78", "eprint_id": 104626, "eprint_status": "archive", "datestamp": "2023-08-19 22:19:32", "lastmod": "2023-10-20 20:40:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Liu-Xiangli", "name": { "family": "Liu", "given": "Xiangli" } }, { "id": "Mao-Yougang", "name": { "family": "Mao", "given": "Yougang" } }, { "id": "Mathias-E-V", "name": { "family": "Mathias", "given": "Errol V." } }, { "id": "Ma-Collin", "name": { "family": "Ma", "given": "Collin" } }, { "id": "Franco-O", "name": { "family": "Franco", "given": "Osmundo" } }, { "id": "Ba-Yong", "name": { "family": "Ba", "given": "Yong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Wang-Tieli", "name": { "family": "Wang", "given": "Tieli" } }, { "id": "Xue-Lijun", "name": { "family": "Xue", "given": "Lijun" } }, { "id": "Zhou-Bing-Sen", "name": { "family": "Zhou", "given": "Bing-Sen" } }, { "id": "Yen-Yun", "name": { "family": "Yen", "given": "Yun" } } ] }, "title": "Study the property of double-ended fluoroalkyl poly(ethylene glycol) hydrogel as a depot for hydrophobic drug delivery using electron paramagnetic resonance technique and cell proliferation assay", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Polymeric drug depot, Rf-PEG hydrogel, Controlled release, Tempol, Chlorambucil, Proliferation assay, Electron paramagnetic resonance", "note": "\u00a9 Springer Science+Business Media, LLC 2007. \n\nReceived: 31 August 2007; Accepted: 12 November 2007; Published online: 13 December 2007. \n\nThis project is supported by the NSF Grant 0351848. Thanks to DOD for funding the EPR spectrometer under the grant d20030904hsi.", "abstract": "Hydrogel formed by fluoroalkyl double-ended polyethylene glycol (R_f-PEG) micelles was studied to assess its properties to encapsulate a hydrophobic electron spin labeled drug, Chlorambucil\u2013Tempol adduct (CT), and to control and sustain the drug release. The drug loaded hydrogel samples were characterized with variable-temperature dependent EPR experiment, and EPR theoretical lineshape analysis. It was found that CT molecules reside in the hydrophobic R_f-cores/IPDU shells of the R_f-PEG micelles and the maximum molecular-level loading capacity was estimated to be 18.8 mg per gram of the R_f-PEG. It has been known that R_f-PEG hydrogel with certain molecular masses for the fluoroalkyl group and the PEG chain shows properties of sol/gel phase coexistence and surface erosion, which represent the favorable condition for a pharmaceutical depot to control the kinetics of drug release. To evaluate the R_f-PEG's biocompatibility and kinetics of the drug release, a cell proliferation assay was carried out on human oropharyngeal carcinoma (KB) cells. The results show that R_f-PEG is biocompatible and able to release CT to the cell media with a constant equilibrium concentration independent of the amount of CT loaded hydrogel.", "date": "2008-03", "date_type": "published", "publication": "Journal of Sol-Gel Science and Technology", "volume": "45", "number": "3", "publisher": "Springer", "pagerange": "269-278", "id_number": "CaltechAUTHORS:20200728-174942242", "issn": "0928-0707", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200728-174942242", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "0351841" }, { "agency": "Department of Defense", "grant_number": "d2003090hsi" } ] }, "doi": "10.1007/s10971-007-1659-y", "resource_type": "article", "pub_year": "2008", "author_list": "Liu, Xiangli; Mao, Yougang; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4m7wh-dj110", "eprint_id": 77951, "eprint_status": "archive", "datestamp": "2023-08-19 22:12:41", "lastmod": "2023-10-25 23:36:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ameri-David-R-L", "name": { "family": "Ameri David", "given": "R. L." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Facile, Efficient Routes to Diverse Protected Thiols and to Their Deprotection and Addition to Create Functional Polymers by Thiol\u2212Ene Coupling", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2008 American Chemical Society. \n\nReceived August 14, 2007; Revised Manuscript Received November 21, 2007. Publication Date (Web): January 25, 2008. \n\nFunding for this research was provided by the Milliken Foundation and the Gates Grubstake Fund at Caltech. We thank Dr. Steven Smith of Procter and Gamble Company for supplying the 1,2-PB precursor materials, as well as Alessa Gambardella and Ming-Hsin Wei for assistance with the synthesis of the protected thiols.\n\nSupplemental Material - ma0718393-file003.pdf
", "abstract": "Carbazole, dinitrobenzoate, phenol, pyridine, and 4-cyano-4'-alkoxybiphenyl side groups were grafted onto pendant vinyl groups of polybutadiene (PB) by thiol\u2212ene addition to yield functional polymer of polydispersity equal to that of the precursor material. Synthesis protocols that are clean (>90% conversion to desired product) and scalable were developed to incorporate a protected thiol group into functional precursors. The resulting acetyl or benzoyl thioesters are suitable for long-term storage, and are conveniently deprotected and added to polymer in a matter of hours in a straightforward procedure that does not require isolation of the thiol intermediate. Alternatively, PB functionalization could be achieved with equal success by reaction with \u03b2-mercaptoethanol (BME), and subsequent esterification of the incorporated hydroxyl groups with a suitable acyl halide. The chemistry described can potentially be applied to add any side group onto any polymer, copolymer, or block copolymer displaying pendant vinyl groups.", "date": "2008-02-26", "date_type": "published", "publication": "Macromolecules", "volume": "41", "number": "4", "publisher": "American Chemical Society", "pagerange": "1151-1161", "id_number": "CaltechAUTHORS:20170605-161033934", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170605-161033934", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Milliken Foundation" }, { "agency": "Gates Grubstake Fund" } ] }, "doi": "10.1021/ma0718393", "primary_object": { "basename": "ma0718393-file003.pdf", "url": "https://authors.library.caltech.edu/records/4m7wh-dj110/files/ma0718393-file003.pdf" }, "resource_type": "article", "pub_year": "2008", "author_list": "Ameri David, R. L. and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/nvh52-akt51", "eprint_id": 68688, "eprint_status": "archive", "datestamp": "2023-08-19 22:08:51", "lastmod": "2023-10-19 23:16:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xia-Yan", "name": { "family": "Xia", "given": "Yan" } }, { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Well-Defined Liquid Crystal Gels from Telechelic Polymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2008 American Chemical Society. Received September 17, 2007.\n\nPublication Date (Web): January 16, 2008.\n\nThis work was supported by the U.S.\nDepartment of Energy. Y.X. thanks the Li Ming Foundation\nfor a Li Ming scholarship. R.V. thanks the James-Irvine\nFoundation and the National Defense Science and Engineering\nfor fellowhips.\n\nSupplemental Material - ja077192j-file002.pdf
", "abstract": "Well-defined liquid crystal networks with controlled molecular weight between cross-links and cross-link functionality were prepared by \"click\" cross-linking of telechelic polymers produced by ring-opening metathesis polymerization (ROMP). The networks readily swell in a small molecule liquid crystal, 5CB, to form LC gels with high swelling ratios. These gels exhibit fast, reversible, and low-threshold optic switching under applied electric fields when they are unconstrained between electrodes. For a given electric field, the LC gels prepared from shorter telechelic polymers showed a reduced degree of switching than their counterparts made from longer polymer strands. The reported approach provides control over important parameters for LC networks, such as the length of the network strands between cross-links, cross-linker functionality, and mesogen density. Therefore, it allows a detailed study of relationships between molecular structure and macroscopic properties of these scientifically and technologically interesting networks.", "date": "2008-02-06", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "130", "number": "5", "publisher": "American Chemical Society", "pagerange": "1735-1740", "id_number": "CaltechAUTHORS:20160627-114737497", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160627-114737497", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)" }, { "agency": "Li Ming Foundation" }, { "agency": "James-Irvine Foundation" }, { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" } ] }, "doi": "10.1021/ja077192j", "primary_object": { "basename": "ja077192j-file002.pdf", "url": "https://authors.library.caltech.edu/records/nvh52-akt51/files/ja077192j-file002.pdf" }, "resource_type": "article", "pub_year": "2008", "author_list": "Xia, Yan; Verduzco, Rafael; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/vejsz-r2735", "eprint_id": 76955, "eprint_status": "archive", "datestamp": "2023-08-19 22:08:35", "lastmod": "2023-10-25 17:01:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mathias-E-V", "name": { "family": "Mathias", "given": "Errol V." } }, { "id": "Liu-Xiangli", "name": { "family": "Liu", "given": "Xiangli" } }, { "id": "Franco-O", "name": { "family": "Franco", "given": "Osmundo" } }, { "id": "Khan-I", "name": { "family": "Khan", "given": "Imran" } }, { "id": "Ba-Yong", "name": { "family": "Ba", "given": "Yong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Model of Drug-Loaded Fluorocarbon-Based Micelles Studied by Electron-Spin Induced ^(19)F Relaxation NMR and Molecular Dynamics Simulation", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2008 American Chemical Society. \n\nReceived June 21, 2007. In Final Form: October 4, 2007.\nPublication Date (Web): December 1, 2007. \n\nThis research was supported by NSF Grant 0351848 and NSF Grant 0619147 for a NMR facility upgrade at CSULA.", "abstract": "R_f-IPDU-PEGs belong to a class of fluoroalkyl-ended poly(ethylene glycol) polymers (R_f-PEGs), where the IPDU (isophorone diurethane) functions as a linker to connect each end of the PEG chain to a fluoroalkyl group. The R_f-IPDU-PEGs form hydrogels in water with favorable sol\u2212gel coexistence properties. Thus, they are promising for use as drug delivery agents. In this study, we introduce an electron-spin induced ^(19)F relaxation NMR technique to probe the location and drug-loading capacity for an electron-spin labeled hydrophobic drug, CT (chlorambucil-tempol adduct), enclosed in the R_f-IPDU-PEG micelle. With the assistance of molecular dynamics simulations, a clear idea regarding the structures of the R_f-IPDU-PEG micelle and its CT-loaded micelle was revealed. The significance of this research lies in the finding that the hydrophobic drug molecules were loaded within the intermediate IPDU shells of the R_f-IPDU-PEG micelles. The molecular structures of IPDU and that of CT are favorably comparable. Consequently, it appears that this study opens a window to modify the linker between the R_f group and the PEG chain for achieving customized structure-based drug-loading capabilities for these hydrogels, while the advantage of the strong affinity among the R_f groups to hold individual micelles together and to interconnect the micellar network is still retained in hopes of maintaining the sol\u2212gel coexistence of the R_f-PEGs.", "date": "2008-02-05", "date_type": "published", "publication": "Langmuir", "volume": "24", "number": "3", "publisher": "American Chemical Society", "pagerange": "692-700", "id_number": "CaltechAUTHORS:20170426-134750006", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170426-134750006", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0351848" }, { "agency": "NSF", "grant_number": "CHE-0619147" } ] }, "doi": "10.1021/la701833w", "resource_type": "article", "pub_year": "2008", "author_list": "Mathias, Errol V.; Liu, Xiangli; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/gfjq3-agd70", "eprint_id": 104411, "eprint_status": "archive", "datestamp": "2023-08-22 10:55:23", "lastmod": "2023-10-20 20:26:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nickerson-C-S", "name": { "family": "Nickerson", "given": "Charles S." } }, { "id": "Park-John", "name": { "family": "Park", "given": "John" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Karageozian-H-L", "name": { "family": "Karageozian", "given": "Hampar" } } ] }, "title": "Rheological properties of the vitreous and the role of hyaluronic acid", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Rheology; Eye; Hyaluronan; Biomechanics; Tension", "note": "\u00a9 2008 Elsevier Ltd. \n\nAccepted 8 April 2008, Available online 4 June 2008. \n\nThe authors wish to thank Prof. Zhen-Gang Wang and Jennifer Witman for discussions regarding network tension. Funding was provided by Vitreoretinal Technologies, Inc. C.S.N. is an ARCS Foundation scholar. \n\nConflict of interest: Two of us (J.P. and H.K.) are employees and stockholders of Vitreoretinal Technologies.", "abstract": "Coordinated rheological and biochemical measurements provide the linear and nonlinear mechanical properties of the vitreous and demonstrate the structural role of hyaluronic acid. \"Cleated\" tools are used to overcome wall slip and avoid tissue compression during measurements of the dynamic moduli of fresh porcine and bovine vitreous. Shear moduli decreased five-fold from initial to steady-state values in the first hour after dissection. Steady-state values (porcine: G\u2032=2.8\u00b10.9 Pa, n=9; bovine: G\u2032=7.0\u00b12.0 Pa, n=17) are significantly greater than previously reported. The decrease in modulus after removal from the eye correlates with a decrease in mass: even in the absence of external driving forces, porcine vitreous expels \u223c5% of its mass within 5 min and continues to decay to a steady-state mass \u223c10% lower than its initial mass. The expelled fluid has a substantial hyaluronan concentration, but very low protein content. These results indicate that the vitreous network is under tension at its native volume and its high initial modulus results from this state of tension. We hypothesize that hyaluronan plays a role in sustaining the \"internal tension\" by Donnan swelling.", "date": "2008-01", "date_type": "published", "publication": "Journal of Biomechanics", "volume": "41", "number": "9", "publisher": "Elsevier", "pagerange": "1840-1846", "id_number": "CaltechAUTHORS:20200716-141332435", "issn": "0021-9290", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200716-141332435", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Vitreoretinal Technologies, Inc." }, { "agency": "ARCS Foundation" } ] }, "doi": "10.1016/j.jbiomech.2008.04.015", "resource_type": "article", "pub_year": "2008", "author_list": "Nickerson, Charles S.; Park, John; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/r01qd-v7406", "eprint_id": 12905, "eprint_status": "archive", "datestamp": "2023-08-19 21:42:45", "lastmod": "2023-10-17 21:14:03", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kimata-Shuichi", "name": { "family": "Kimata", "given": "Shuichi" } }, { "id": "Sakurai-Takashi", "name": { "family": "Sakurai", "given": "Takashi" } }, { "id": "Nozue-Yoshinobu", "name": { "family": "Nozue", "given": "Yoshinobu" } }, { "id": "Kasahara-Tatsuya", "name": { "family": "Kasahara", "given": "Tatsuya" } }, { "id": "Yamaguchi-Noboru", "name": { "family": "Yamaguchi", "given": "Noboru" } }, { "id": "Karino-Takeshi", "name": { "family": "Karino", "given": "Takeshi" } }, { "id": "Shibayama-Mitsuhiro", "name": { "family": "Shibayama", "given": "Mitsuhiro" } } ] }, "title": "Molecular Aspects of Flow-Induced Crystallization of Polymers", "ispublished": "pub", "full_text_status": "public", "note": "Copyright \u00a9 2008 Progress of Theoretical Physics. \n\nCollaborators on this research include former graduate students Lucia Fernandez-Ballaster (ESRF, France), Derek Thurman (ExxonMobil, USA), Guruswamy Kumaraswamy (NCL, India), academic collaborators including Mitsuhiro Shibayama (ISSP U. Tokyo, Japan) and industrial scientists including Motohiro Seki (Mitsubishi Chemical, Japan), Shuichi Kimata (Sumitomo Chemical, Japan), Raj Krishnaswamy (Metabolix, USA), J.P. Autran (Procter & Gamble), David Lohse (ExxonMobil) and their colleagues.", "abstract": "Like teeth, bone and sea shells, semicrystalline polymers combine strength with toughness by forming a nano-scale composite with platelet-like crystals stacked with noncrystalline material between them. The morphology and orientation distribution of the nanostructure dictate the material properties. Dynamics of polymer chains in the melt play an important role in controlling the morphology, especially under the influence of flow. Using bimodal isotactic polypropylenes to reveal the effects of small concentrations of very long chains, in collaboration with Mitsubishi Chemical, we show that long chains have a profound effect when they are so long that they can undergo chain stretching, particularly when the long chain concentration is at or above their overlap concentration. When subjected to identical stress at identical subcooling, the blends containing long chains undergo dramatically faster crystallization with very strong orientation. The \"long chains\" enhance formation of highly oriented crystallization precursors (\"shish\") on which oriented lamellae (\"kebabs\") subsequently grow. In collaboration with Sumitomo Chemical and The University of Tokyo, we test the hypothesis that the kebabs are actually composed of long chains using isotopic labelling of selected fractions and small angle neutron scattering (SANS). The results show that long chains in the shish are at the same concentration as they are everywhere else: there is no neutron scattering contrast when the long chains are the deuterium labelled ones! The long chains are essential for the formation of shish and they play their role by \"recruiting\" adjacent chains into formation of the shish. Placing molecular defects on the longest chains inhibits their ability to serve this role, providing a molecular tool to independently control the melt elasticity (by choice of the length and concentration of the long chains) and the flow-induced crystallization behavior (by selecting the comonomer content, for example, of the long chains).", "date": "2008", "date_type": "published", "publication": "Progress of Theoretical Physics Supplement", "number": "175", "publisher": "Progress of Theoretical Physics", "pagerange": "10-16", "id_number": "CaltechAUTHORS:KORptps08", "issn": "0375-9687", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KORptps08", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2008", "author_list": "Kornfield, Julia A.; Kimata, Shuichi; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/k7zqf-8zb92", "eprint_id": 79295, "eprint_status": "archive", "datestamp": "2023-08-19 20:55:40", "lastmod": "2023-10-26 14:46:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rendon-S", "name": { "family": "Rendon", "given": "Stanley" } }, { "id": "Burghardt-W-R", "name": { "family": "Burghardt", "given": "Wesley R." } }, { "id": "Auad-M-L", "name": { "family": "Auad", "given": "Maria L." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Shear-Induced Alignment of Smectic Side Group Liquid Crystalline Polymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2007 American Chemical Society. \n\nReceived 19 December 2006. Published online 14 August 2007. Published in print 1 September 2007. \n\nWe thank Michael. D. Kempe for synthesizing the SGLCPs used in this investigation. We gratefully acknowledge financial support from the Air Force Office of Scientific Research (AFOSR)-LC MURI, the National Science Foundation (Grants DMI-0099542 and DMI-0521823), Fundaci\u00f3n Antorchas (Argentina), and CONICET (Argentina). X-ray scattering experiments were conducted at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) Synchrotron Research Center located at Sector 5 of the Advanced Photon Source of Argonne National Laboratory. DND-CAT is supported by the E.I. DuPont de Nemours & Co., the Dow Chemical Company, and the National Science Foundation through Grant DMR-9304725 and the State of Illinois through the Department of Commerce and the Board of Higher Education Grant IBHE HECA NWU 96. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Basic Energy Sciences, Office of Energy Research, under Contract No. W-31-102-Eng-38.", "abstract": "Large amplitude oscillatory shear (LAOS) is frequently capable of generating macroscopic alignment from an initially random orientation distribution in ordered polymer fluids. Side-group liquid crystalline polymers are of special interest in that the flow field may couple differently to the polymer backbone and the mesogen ordering. We report combined rheological and in situ X-ray scattering investigations of LAOS-induced alignment in smectic side-group LCPs. Synchrotron X-ray scattering is used to study orientation development using a rotating disk shear cell in which orientation is tracked within the flow-vorticity (1\u22123) plane. In all cases, we find that shear promotes anisotropic orientation states in which the lamellar normal tends to align along the vorticity direction of the shear flow (\"perpendicular\" alignment). We examine the effects of shear strain amplitude and polymer backbone molecular weight on the ability of LAOS to induce alignment. Rheological measurements of the dynamic moduli reveal that large amplitude shearing in the smectic phase causes a notable decrease in the modulus. X-ray and rheological data demonstrate that increasing strain promotes higher degrees of orientation, while increasing molecular weight impedes development of smectic alignment.", "date": "2007-09-04", "date_type": "published", "publication": "Macromolecules", "volume": "40", "number": "18", "publisher": "American Chemical Society", "pagerange": "6624-6630", "id_number": "CaltechAUTHORS:20170724-101025537", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-101025537", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)" }, { "agency": "NSF", "grant_number": "DMI-0099542" }, { "agency": "NSF", "grant_number": "DMI-0521823" }, { "agency": "Fundaci\u00f3n Antorchas" }, { "agency": "Consejo Nacional de Investigaciones Cient\u00edficas y T\u00e9cnicas (CONCIET)" }, { "agency": "E.I. DuPont de Nemours & Co." }, { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "DMR-9304725" }, { "agency": "Illinois Department of Commerce", "grant_number": "IBHE HECA NWU 96" }, { "agency": "Department of Energy (DOE)", "grant_number": "W-31-102-Eng-38" }, { "agency": "Illinois Board of Higher Education" } ] }, "doi": "10.1021/ma062912c", "resource_type": "article", "pub_year": "2007", "author_list": "Rendon, Stanley; Burghardt, Wesley R.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/n3n5k-w7q62", "eprint_id": 8799, "eprint_status": "archive", "datestamp": "2023-08-22 09:35:57", "lastmod": "2023-10-16 21:44:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Scruggs-N-R", "name": { "family": "Scruggs", "given": "Neal R." } }, { "id": "Sprunt-S", "name": { "family": "Sprint", "given": "Samuel" } }, { "id": "Palffy-Muhoray-P", "name": { "family": "Palffy-Muhoray", "given": "Peter" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Director dynamics in liquid-crystal physical gels", "ispublished": "pub", "full_text_status": "public", "note": "This journal is \u00a9 The Royal Society of Chemistry 2007. \n\nReceived 19th January 2007, Accepted 14th May 2007. First published on the web 30th May 2007.", "abstract": "Nematic liquid-crystal (LC) elastomers and gels have a rubbery polymer network coupled to the nematic director. While LC elastomers show a single, non-hydrodynamic relaxation mode, dynamic light-scattering studies of self-assembled liquid-crystal gels reveal orientational fluctuations that relax over a broad time scale. At short times, the relaxation dynamics exhibit hydrodynamic behavior. In contrast, the relaxation dynamics at long times are non-hydrodynamic, highly anisotropic, and increase in amplitude at small scattering angles. We argue that the slower dynamics arise from coupling between the director and the physically associated network, which prevents director orientational fluctuations from decaying completely at short times. At long enough times the network restructures, allowing the orientational fluctuations to fully decay. Director dynamics in the self-assembled gels are thus quite distinct from those observed in LC elastomers in two respects: they display soft orientational fluctuations at short times, and they exhibit at least two qualitatively distinct relaxation processes.", "date": "2007-08", "date_type": "published", "publication": "Soft Matter", "volume": "3", "number": "8", "publisher": "Soft Matter", "pagerange": "993-1002", "id_number": "CaltechAUTHORS:VERsm07", "issn": "1744-6848", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:VERsm07", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1039/b700871f", "primary_object": { "basename": "VERsm07.gif", "url": "https://authors.library.caltech.edu/records/n3n5k-w7q62/files/VERsm07.gif" }, "related_objects": [ { "basename": "VERsm07.pdf", "url": "https://authors.library.caltech.edu/records/n3n5k-w7q62/files/VERsm07.pdf" }, { "basename": "medium.png", "url": "https://authors.library.caltech.edu/records/n3n5k-w7q62/files/medium.png" }, { "basename": "small.png", "url": "https://authors.library.caltech.edu/records/n3n5k-w7q62/files/small.png" } ], "resource_type": "article", "pub_year": "2007", "author_list": "Verduzco, Rafael; Scruggs, Neal R.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/kabkr-98r09", "eprint_id": 51949, "eprint_status": "archive", "datestamp": "2023-08-19 20:12:54", "lastmod": "2023-10-18 18:44:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kimata-Shuichi", "name": { "family": "Kimata", "given": "Shuichi" } }, { "id": "Sakurai-Takashi", "name": { "family": "Sakurai", "given": "Takashi" } }, { "id": "Nozue-Yoshinobu", "name": { "family": "Nozue", "given": "Yoshinobu" } }, { "id": "Kasahara-Tatsuya", "name": { "family": "Kasahara", "given": "Tatsuya" } }, { "id": "Yamaguchi-Noboru", "name": { "family": "Yamaguchi", "given": "Noboru" } }, { "id": "Karino-Takeshi", "name": { "family": "Karino", "given": "Takeshi" } }, { "id": "Shibayama-Mitsuhiro", "name": { "family": "Shibayama", "given": "Mitsuhiro" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Molecular Basis of the Shish-Kebab Morphology in Polymer Crystallization", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2007 American Association for the Advancement of Science.\n\nReceived 19 January 2007; accepted 23 March 2007.\n\nThis work was performed using SANS-U of the Institute\nfor Solid State Physics, the University of Tokyo\n(no. 05.5542). Supported by the NSF Division of\nMaterials Research (DMR-0505393 and Materials\nResearch Science and Engineering Center DMR-0080065).\n\nSupplemental Material - Kimata.SOM.pdf
", "abstract": "In the rich and long-standing literature on the flow-induced formation of oriented precursors to polymer crystallization, it is often asserted that the longest, most extended chains are the dominant molecular species in the \"shish\" of the \"shish-kebab\" formation. We performed a critical examination of this widely held view, using deuterium labeling to distinguish different chain lengths within an overall distribution. Small-angle neutron-scattering patterns of the differently labeled materials showed that long chains are not overrepresented in the shish relative to their concentration in the material as a whole. We observed that the longest chains play a catalytic role, recruiting other chains adjacent to them into formation of the shish.", "date": "2007-05-18", "date_type": "published", "publication": "Science", "volume": "316", "number": "5827", "publisher": "American Association for the Advancement of Science", "pagerange": "1014-1017", "id_number": "CaltechAUTHORS:20141119-095352598", "issn": "0036-8075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141119-095352598", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0505393" }, { "agency": "NSF", "grant_number": "DMR-0080065" } ] }, "doi": "10.1126/science.1140132", "primary_object": { "basename": "Kimata.SOM.pdf", "url": "https://authors.library.caltech.edu/records/kabkr-98r09/files/Kimata.SOM.pdf" }, "resource_type": "article", "pub_year": "2007", "author_list": "Kimata, Shuichi; Sakurai, Takashi; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0jxvd-j9649", "eprint_id": 76264, "eprint_status": "archive", "datestamp": "2023-08-22 08:39:47", "lastmod": "2023-10-25 15:36:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hernandez-L", "name": { "family": "Hernandez", "given": "L." } }, { "id": "Rudolph-M", "name": { "family": "Rudolph", "given": "M." } }, { "id": "Lammertink-R", "name": { "family": "Lammertink", "given": "R." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J." }, "orcid": "0000-0001-6746-8634" }, { "id": "Zurita-C", "name": { "family": "Zurita", "given": "C." } }, { "id": "Gomez-F-A", "name": { "family": "Gomez", "given": "F. A." } } ] }, "title": "Determination of Binding Constants of Polyethylene Glycol Vancomycin Derivatives to Peptide Ligands Using Affinity Capillary Electrophoresis", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Affinity capillary electrophoresis; Vancomycin; Binding constants; Polyethylene glycol", "note": "\u00a9 Friedr. Vieweg & Sohn Verlag/GWV Fachverlage GmbH 2006. \n\nReceived: 2 August 2006 / Revised: 7 November 2006 / Accepted: 21 November 2006 / Online publication: 21 December 2006 \n\nThe authors gratefully acknowledge financial support for this research by grants from the National Science Foundation (CHE-0515363, DMR-0351848, DMR-0080065, DMR-0520565), and the National Institutes of Health (1R15 AI055515-01, 1R15AI65468-01, and GM54939).", "abstract": "Vancomycin (Van) from Streptomyces orientalis has been derivatized with polyethylene glycol [PEG; PEG-550 (1), 750 (2), 1,100 (3), 2,000 (4), 5,000 (5), and 8,000 (6) g mol\u22121] at the N-terminus of the glycopeptide backbone and their binding to d-Ala-d-Ala terminus peptides assessed using affinity capillary electrophoresis (ACE). Utilizing ACE, a plug of Van-PEG and non-interacting standards are injected and electrophoresed. Analysis of the change in the relative migration time ratio of the Van-PEG species, relative to the non-interacting standards, as a function of the concentration of peptide, yields a value for the binding constant (K_b). Values of K_b for N-acetyl-d-Ala-d-Ala, 7 to the Van-PEG derivatives are weaker than those for N_\u03b1,N_\u03b5-diacetyl-Lys-d-Ala-d-Ala, 8 (for example, values of K_b for 7-1 and 8-1 are 1.8 and 47.7 \u00d7 10^3 M^(\u22121), respectively). These results demonstrate that derivatization of Van with PEG has little effect on the affinity of d-Ala-d-Ala peptide ligands to it. The findings further prove the versatility of ACE and its ability to estimate binding parameters of ligands to antibiotics.", "date": "2007-03", "date_type": "published", "publication": "Chromatographia", "volume": "65", "number": "5-6", "publisher": "Springer", "pagerange": "299-303", "id_number": "CaltechAUTHORS:20170408-165046683", "issn": "0009-5893", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-165046683", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-0515363" }, { "agency": "NSF", "grant_number": "DMR-0351848" }, { "agency": "NSF", "grant_number": "DMR-0080065" }, { "agency": "NSF", "grant_number": "DMR-0520565" }, { "agency": "NIH", "grant_number": "1R15 AI055515-01" }, { "agency": "NIH", "grant_number": "1R15AI65468-01" }, { "agency": "NIH", "grant_number": "GM54939" } ] }, "doi": "10.1365/s10337-006-0148-8", "resource_type": "article", "pub_year": "2007", "author_list": "Hernandez, L.; Rudolph, M.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/vg383-s9p87", "eprint_id": 79317, "eprint_status": "archive", "datestamp": "2023-08-19 19:29:58", "lastmod": "2023-10-26 14:48:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mackel-M-J", "name": { "family": "Mackel", "given": "Michael J." } }, { "id": "Sanchez-S", "name": { "family": "Sanchez", "given": "Sergio" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Humidity-Dependent Wetting Properties of High Hysteresis Surfaces", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2007 American Chemical Society. \n\nReceived 20 June 2006. Published online 9 November 2006. Published in print 1 January 2007. \n\nWe thank Jeffrey A. Hubbell for inspiration. Sandra M. Troian assisted us with two especially valuable conversations during the early stages of this project. 6KC10 was synthesized by Giyoong Tae. Ellipsometry was performed at the Molecular Materials Research Center of the Beckman Institute of the California Institute of Technology. M.J.M. was supported in part by a NSF Graduate Student Fellowship.", "abstract": "The advancing contact angle (\u03b8_(adv)) of water on thin films (\u223c1 \u03bcm) of poly(ethylene glycol) (PEG) with fluoroalkyl endgroups (6 kg/mol PEG with 10-carbon fluoroalkyl, denoted 6KC10) changes strongly with relative humidity (RH). Films of 6KC10 on silicon wafers pretreated with a fluorinated alkylsilane (TFOS) display \u03b8adv increasing from 75\u00b0 at 12% RH to 95\u00b0 at 94% RH. The surprising transition to nonwetting character at high humidity is attributed to fluoroalkyl groups ordering at the air\u2212hydrogel interface when they are liberated by dissolution of PEG crystallites above 85% RH. When water is withdrawn from a drop on 6KC10, the contact line does not recede. This extreme hysteresis is attributed to restructuring of the gel to bury the fluoroalkyl groups when in contact with water.", "date": "2007-01-02", "date_type": "published", "publication": "Langmuir", "volume": "23", "number": "1", "publisher": "American Chemical Society", "pagerange": "3-7", "id_number": "CaltechAUTHORS:20170725-072343555", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170725-072343555", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1021/la0617762", "resource_type": "article", "pub_year": "2007", "author_list": "Mackel, Michael J.; Sanchez, Sergio; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/jv9f5-ttb62", "eprint_id": 53243, "eprint_status": "archive", "datestamp": "2023-08-19 19:18:21", "lastmod": "2023-10-19 14:40:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Wei", "name": { "family": "Shen", "given": "Wei" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Dynamic Properties of Artificial Protein Hydrogels Assembled through Aggregation of Leucine Zipper Peptide Domains", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2007 American Chemical Society\n\nReceived July 6, 2006; Revised Manuscript Received November 21, 2006\n\nThe authors acknowledge the NSF Center for the Science and Engineering of Materials for financial support.\n\nSupplemental Material - ma0615194si20061121_061257.pdf
", "abstract": "Network relaxation dynamics of hydrogels formed from a genetically engineered multidomain protein (AC_(10)A, where A is an associative leucine zipper domain and C_(10) is a random-coil polyelectrolyte domain) were investigated by shear rheometry. Physical gels form by tetrameric association of the leucine zipper end-blocks (A). The longest stress relaxation time (\u03c4_r) of these gels varies strongly with pH, increasing from \u03c4_r \u2248 80 s at pH 8.0 to \u03c4_r \u2248 1000 s at pH 7.0. The rate of strand exchange of the end-blocks was studied by using fluorescence quenching of the labeled form of the A domain. Fluorescence is quenched in solutions of fluorescein-labeled A; dequenching occurs when labeled A is mixed with a 60-fold excess of the unlabeled peptide. The dequenching transient after mixing reveals the characteristic strand exchange time (\u03c4_e) of the A domain. As pH decreases from 8.0 to 7.0, \u03c4_e increases from ca. 200 s to ca. 4500 s. Thus, \u03c4_r of AC_(10)A hydrogels and \u03c4_e of the A domain vary in parallel with pH. The strong correlation between macroscopic and molecular properties indicates that network relaxation is regulated by the lifetime of associations in the transient network. Because the rate of leucine zipper strand exchange is sensitive to interstrand electrostatic interactions, the relaxation behavior of artificial protein hydrogels can be engineered systematically by genetic programming of the amino acid sequence.", "date": "2007", "date_type": "published", "publication": "Macromolecules", "volume": "40", "number": "3", "publisher": "American Chemical Society", "pagerange": "689-692", "id_number": "CaltechAUTHORS:20150114-134355362", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150114-134355362", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/ma0615194", "primary_object": { "basename": "ma0615194si20061121_061257.pdf", "url": "https://authors.library.caltech.edu/records/jv9f5-ttb62/files/ma0615194si20061121_061257.pdf" }, "resource_type": "article", "pub_year": "2007", "author_list": "Shen, Wei; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/aq5tr-zm118", "eprint_id": 8568, "eprint_status": "archive", "datestamp": "2023-08-22 07:55:02", "lastmod": "2023-10-16 21:33:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Wei", "name": { "family": "Shen", "given": "Wei" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Structure and mechanical properties of artificial protein hydrogels assembled through aggregation of leucine zipper peptide domains", "ispublished": "pub", "full_text_status": "public", "note": "This journal is \u00a9 The Royal Society of Chemistry 2007. \n\nReceived 31st July 2006, Accepted 20th October 2006. First published on the web 9th November 2006. \n\nThe authors acknowledge the NSF Center for the Science and Engineering of Materials for financial support.", "abstract": "Artificial protein hydrogels made from a triblock protein (designated AC10A, where A is an acidic zipper domain and C10 comprises 10 repeats of the nonapeptide sequence exhibit normalized plateau storage moduli (G/nkT) less than 0.13 at all concentrations, pH values, and ionic strengths examined. These gels are surprisingly soft due to loop formation at the expense of bridges between physical junctions. Molecular-level evidence of loop formation is provided by strong fluorescence energy transfer (FRET) between distinct chromophores placed at the C- and N-termini of labelled chains diluted in an excess of unlabelled chains. The tendency to form loops originates from the compact size of the random coil midblock (mean RH(C10) 20 \u00c5, determined from quasi-elastic light scattering of C10), and is facilitated by the ability of the leucine zipper domains to form antiparallel aggregates. Although the aggregation number of the leucine zipper domains is small (tetrameric, determined from multi-angle static light scattering of AC10 diblock), the average center-to-center distance between aggregates is roughly 1.5 times the average end-to-end distance of the C10 domain in a 7% w/v network. To avoid stretching the C10 domain, the chains tend to form loops. Changes in pH or ionic strength that expand the polyelectrolyte midblock favor bridging, leading to greater G as long as leucine zipper endblocks do not dissociate. Understanding of the network structure provided successful design strategies to increase the rigidity of these hydrogels. In contrast to intuitive design concepts for rubber and gel materials, it was shown that increasing either the length or the charge density of the midblock increases rigidity, because fewer chains are wasted in loop formation.", "date": "2007", "date_type": "published", "publication": "Soft Matter", "volume": "3", "number": "1", "publisher": "Soft Matter", "pagerange": "99-107", "id_number": "CaltechAUTHORS:SHEsm07", "issn": "1744-6848", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SHEsm07", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1039/b610986a", "primary_object": { "basename": "SHEsm07.gif", "url": "https://authors.library.caltech.edu/records/aq5tr-zm118/files/SHEsm07.gif" }, "related_objects": [ { "basename": "SHEsm07.pdf", "url": "https://authors.library.caltech.edu/records/aq5tr-zm118/files/SHEsm07.pdf" }, { "basename": "medium.png", "url": "https://authors.library.caltech.edu/records/aq5tr-zm118/files/medium.png" }, { "basename": "small.png", "url": "https://authors.library.caltech.edu/records/aq5tr-zm118/files/small.png" } ], "resource_type": "article", "pub_year": "2007", "author_list": "Shen, Wei; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/rf37y-rek90", "eprint_id": 59724, "eprint_status": "archive", "datestamp": "2023-08-19 18:55:44", "lastmod": "2023-10-23 22:39:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Olsen-A-P", "name": { "family": "Olsen", "given": "Adam P." } }, { "id": "Flagan-R-C", "name": { "family": "Flagan", "given": "Richard C." }, "orcid": "0000-0001-5690-770X" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Manipulation of Athermal Nuclei in Aqueous Poly(ethylene oxide) by Scanning Activity Gravimetric Analysis", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2006 American Chemical Society. \n\nReceived July 4, 2006. \n\nThe authors dedicate this paper to Hermann Janeschitz-Kriegl on the occasion of his 82nd birthday and thank him for stimulating this work. The authors also thank Zhen-Gang Wang of the California Institute of Technology for insightful discussions. This material is based upon work supported by the National Science Foundation under Grants 0505393 and 0080065.", "abstract": "We show that polymer solutions exhibit memory effects as they undergo repeated dissolution (deliquescence) and crystallization (efflorescence) transitions, similar to those previously observed in polymer melts. These memory effects have been probed using scanning activity gravimetric analysis (SAGA) on aqueous poly(ethylene oxide). SAGA is a new method that enables manipulation of the thermodynamic state of a polymer/solvent system under isothermal conditions. The measurements have been performed on individual micron-sized (\u223c10 ng) polymer particles that are levitated electrostatically and subjected to programmed changes in the activity of solvent vapor. The particle mass rapidly changes due to sorption or evaporation of solvent in response to changes in vapor activity, providing insights into the changing state of the polymer/solvent system. Repeated cycling of solvent activity within a levitated particle reveals systematic shifts up and down in the deliquescence and efflorescence activities depending upon the extreme activities reached. Melt memory effects have previously been attributed to remnants of lamellar crystals that persist beyond the nominal melting temperature. The present observations suggest that the thickness of these remnants evolves in solution, changing the supersaturation at which they may serve as athermal nuclei. An extension to the classical thermodynamic model of lamellae that includes a reduced interfacial tension at the perimeter of the high energy fold surface predicts the existence of a metastable radius that allows remnants to slowly increase or decrease in thickness under certain conditions, thereby rationalizing the ability to manipulate efflorescence behavior. We also present an analysis that suggests that SAGA can be extended to other polymer/solvent systems with the appropriate choice of temperature.", "date": "2006-11-28", "date_type": "published", "publication": "Macromolecules", "volume": "39", "number": "24", "publisher": "American Chemical Society", "pagerange": "8419-8427", "id_number": "CaltechAUTHORS:20150818-110056580", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-110056580", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "0505393" }, { "agency": "NSF", "grant_number": "0080065" } ] }, "doi": "10.1021/ma0614949", "resource_type": "article", "pub_year": "2006", "author_list": "Olsen, Adam P.; Flagan, Richard C.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/5d3cp-bkq74", "eprint_id": 59722, "eprint_status": "archive", "datestamp": "2023-08-19 18:27:46", "lastmod": "2023-10-23 22:39:10", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Olsen-A-P", "name": { "family": "Olsen", "given": "Adam P." } }, { "id": "Flagan-R-C", "name": { "family": "Flagan", "given": "Richard C." }, "orcid": "0000-0001-5690-770X" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Scanning Activity Gravimetric Analysis", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2006 American Chemical Society. \n\nReceived May 8, 2006; Revised Manuscript Received June 19, 2006. \n\nThe authors thank Professor Chris Sorenson and Matthew Berg of Kansas State University, Professor Zhen-Gang Wang of California Institute of Technology, and Professor Nitash Balsara of University of California - Berkeley for insightful discussions. This work was funded by the National Science Foundation (DMR-0505393 and the MRSEC Program under Award DMR-0080065).\n\nSupplemental Material - ma061027rsi20060619_050435.pdf
", "abstract": "We introduce a new technique -- scanning activity gravimetric analysis (SAGA)for investigating phase transitions in semicrystalline polymers. Isothermal growth and dissolution of polymer crystallites within picogram to milligram samples are manifested by mass changes in response to changes in the activity of sorbed solvent vapor. Single charged particles are levitated and weighed in an electrostatic field, providing access to highly supersaturated states. Phase transitions are inferred from simultaneous sorption and light scattering measurements. Analogous to differential scanning calorimetry, scanning solvent activity up and down exposes broad transitions between the semicrystalline solid state and the dissolved state, which are influenced by sample history. We demonstrate repeated dissolution and crystallization of an 11 ng sample of poly(ethylene oxide) by controlling the activity of sorbed water vapor and observe self-nucleation of crystallites from partially and fully solvated states.", "date": "2006-08-22", "date_type": "published", "publication": "Macromolecules", "volume": "39", "number": "17", "publisher": "American Chemical Society", "pagerange": "5946-5951", "id_number": "CaltechAUTHORS:20150818-105917885", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-105917885", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0505393" }, { "agency": "NSF", "grant_number": "DMR-0080065" } ] }, "doi": "10.1021/ma061027r", "primary_object": { "basename": "ma061027rsi20060619_050435.pdf", "url": "https://authors.library.caltech.edu/records/5d3cp-bkq74/files/ma061027rsi20060619_050435.pdf" }, "resource_type": "article", "pub_year": "2006", "author_list": "Olsen, Adam P.; Flagan, Richard C.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/qv4pr-7qk74", "eprint_id": 79292, "eprint_status": "archive", "datestamp": "2023-08-19 17:53:33", "lastmod": "2023-10-26 14:46:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Scruggs-N-R", "name": { "family": "Scruggs", "given": "Neal R." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Lal-Jyotsana", "name": { "family": "Lal", "given": "Jyotsana" } } ] }, "title": "Using the \"Switchable\" Quality of Liquid Crystal Solvents To Mediate Segregation between Coil and Liquid Crystalline Polymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2006 American Chemical Society. \n\nReceived 11 November 2005. Published online 6 May 2006. Published in print 1 May 2006. \n\nThis work benefited from use of the shared facilities supported by the MRSEC Program of the National Science Foundation under Award DMR-0080065. The authors also acknowledge financial support from the AFOSR LC-MURI (f4962-97-1-0014). We thank Ed Lang (Argonne National Laboratory, Intense Pulsed Neutron Source) for assistance with SANS experiments and Rafael Verduzco for helpful discussions. A National Defense Science and Engineering Graduate Fellowship awarded to N.R.S. is greatly appreciated.", "abstract": "The discontinuous change in solvent quality of a liquid crystal (LC) solvent, 5CB, at the nematic\u2212isotropic phase transition produces abrupt changes in the phase behavior of solutions of coil and LC polymers and in the self-assembly of coil\u2212LC block copolymers. Nematic 5CB is strongly selective for a side-group liquid crystal polymer (SGLCP), and isotropic 5CB is a good solvent for both SGLCP and a random coil (polystyrene, PS). In nematic 5CB, unfavorable LC\u2212PS interactions drive phase separation in SGLCP\u2212PS\u2212LC ternary solutions and drive micellization of PS\u2212SGLCP diblocks. In isotropic 5CB, rich phase behavior occurs in both ternary solutions and block copolymer solutions. Despite the fact that isotropic 5CB is a good solvent for both SGLCP and PS, segregation can occur due to the asymmetric solvent effect (i.e., the preference of the solvent for the SGLCP). In concentrated isotropic solutions, unfavorable SGLCP\u2212PS interactions become dominant.", "date": "2006-05-30", "date_type": "published", "publication": "Macromolecules", "volume": "39", "number": "11", "publisher": "American Chemical Society", "pagerange": "3921-3926", "id_number": "CaltechAUTHORS:20170724-094445465", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-094445465", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0080065" }, { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "f4962-97-1-0014" }, { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" } ] }, "doi": "10.1021/ma052414o", "resource_type": "article", "pub_year": "2006", "author_list": "Scruggs, Neal R.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/27e15-d5k74", "eprint_id": 3920, "eprint_status": "archive", "datestamp": "2023-08-22 05:34:36", "lastmod": "2023-10-16 16:13:08", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael D." } }, { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Scruggs-N-R", "name": { "family": "Scruggs", "given": "Neal R." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Rheological study of structural transitions in triblock copolymers in a liquid crystal solvent", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 The Royal Society of Chemistry 2006 \n\nReceived 12th January 2006, Accepted 23rd March 2006, First published on the web 4th April 2006 \n\nThe authors acknowledge financial support from the AFOSR LC-MURI (f4962-97-1-0014), the ARCS foundation, the NSF Department of Materials Research (DMR-0216491), the NDSEG fellowship, and the James-Irvine Foundation. We would like to thank Steven Smith of Procter and Gamble for providing us with 1,2-polybutadiene samples, and Mar\u00eda Lujan Auad for helpful discussions. \n\nM. D. K., R. V. and N. R. S. contributed equally to this work.", "abstract": "Rheological properties of triblock copolymers dissolved in a nematic liquid crystal (LC) solvent demonstrate that their microphase separated structure is heavily influenced by changes in LC order. Nematic gels were created by swelling a well-defined, high molecular weight ABA block copolymer with the small-molecule nematic LC solvent 4-pentyl-4-cyanobiphenyl (5CB). The B midblock is a side-group liquid crystal polymer (SGLCP) designed to be soluble in 5CB and the A endblocks are polystyrene, which is LC-phobic and microphase separates to produce a physically cross-linked, thermoreversible, macroscopic polymer network. At sufficiently low polymer concentration a plateau modulus in the nematic phase, characteristic of a gel, abruptly transitions to terminal behavior when the gel is heated into its isotropic phase. In more concentrated gels, endblock aggregates persist into the isotopic phase. Dramatic changes in network structure are observed over small temperature windows (as little as 1 \u00b0C) due to tccche rapidly changing LC order near the isotropization point. The discontinuous change in solvent quality produces an abrupt change in viscoelastic properties for three polymers having different pendant mesogenic groups and matched block lengths.", "date": "2006-05", "date_type": "published", "publication": "Soft Matter", "volume": "2", "number": "5", "publisher": "Soft Matter", "pagerange": "422-431", "id_number": "CaltechAUTHORS:KEMsoftm06", "issn": "1744-6848", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KEMsoftm06", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1039/b600483k", "primary_object": { "basename": "KEMsoftm06.pdf", "url": "https://authors.library.caltech.edu/records/27e15-d5k74/files/KEMsoftm06.pdf" }, "resource_type": "article", "pub_year": "2006", "author_list": "Kempe, Michael D.; Verduzco, Rafael; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/fbyfe-6fn23", "eprint_id": 2715, "eprint_status": "archive", "datestamp": "2023-08-22 05:31:16", "lastmod": "2023-10-13 23:41:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Meng-Guangnan", "name": { "family": "Meng", "given": "Guangnan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Meyer-R-B", "name": { "family": "Meyer", "given": "Robert B." } } ] }, "title": "Buckling Instability in Liquid Crystalline Physical Gels", "ispublished": "pub", "full_text_status": "public", "keywords": "stability; free energy; rubber; polymer gels; nematic liquid crystals; elastic deformation; buckling", "note": "\u00a9 2006 The American Physical Society \n\n(Received 1 December 2005; revised 28 February 2006; published 13 April 2006) \n\nThis work was supported by the Department of Defense, the James Irvine Foundation, AFOSR LC-MURI (F49620-97-1-0014), NSF Grant No. DMI-0523083, the W. M. Keck Foundation, and at Brandeis NSF Grant No. DMR-0322530.\n\nPublished - VERprl06.pdf
", "abstract": "In a nematic gel we observe a low-energy buckling deformation arising from soft and semisoft elastic modes. We prepare the self-assembled gel by dissolving a coil\u2013side-group liquid-crystalline polymer\u2013coil copolymer in a nematic liquid crystal. The gel has long network strands and a precisely tailored structure, making it ideal for studying nematic rubber elasticity. Under polarized optical microscopy we observe a striped texture that forms when gels uniformly aligned at 35 \u00b0C are cooled to room temperature. We model the instability using the molecular theory of nematic rubber elasticity, and the theory correctly captures the change in pitch length with sample thickness and polymer concentration. This buckling instability is a clear example of a low-energy deformation that arises in materials where polymer network strains are coupled to the director orientation.", "date": "2006-04-14", "date_type": "published", "publication": "Physical Review Letters", "volume": "96", "number": "14", "publisher": "American Physical Society", "pagerange": "Art. No. 147802", "id_number": "CaltechAUTHORS:VERprl06", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:VERprl06", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Defense" }, { "agency": "James Irvine Foundation" }, { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "F49620-97-1-0014" }, { "agency": "NSF", "grant_number": "DMI-0523083" }, { "agency": "W. M. Keck Foundation" }, { "agency": "NSF", "grant_number": "DMR-0322530" } ] }, "doi": "10.1103/PhysRevLett.96.147802", "primary_object": { "basename": "VERprl06.pdf", "url": "https://authors.library.caltech.edu/records/fbyfe-6fn23/files/VERprl06.pdf" }, "resource_type": "article", "pub_year": "2006", "author_list": "Verduzco, Rafael; Meng, Guangnan; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/hcbzz-2vn02", "eprint_id": 53273, "eprint_status": "archive", "datestamp": "2023-08-19 17:17:02", "lastmod": "2023-10-19 14:43:08", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Wei", "name": { "family": "Shen", "given": "Wei" } }, { "id": "Zhang-Kechun", "name": { "family": "Zhang", "given": "Kechun" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Tuning the erosion rate of artificial protein hydrogels through control of network topology", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2006 Nature Publishing Group\n\nReceived 23 June 2005; accepted 6 December 2005; published 29 January 2006.\n\nThe authors acknowledge the NSF Center for the Science and Engineering of Materials for financial support. Correspondence and requests for materials should be addressed to J.A.K. or D.A.T. Supplementary Information accompanies this paper on www.nature.com/naturematerials.\n\nSupplemental Material - nmat1573-s1.pdf
", "abstract": "Erosion behaviour governs the use of physical hydrogels in biomedical applications ranging from controlled release to cell encapsulation. Genetically engineered protein hydrogels offer unique means of controlling the erosion rate by engineering their amino acid sequences and network topology. Here, we show that the erosion rate of such materials can be tuned by harnessing selective molecular recognition, discrete aggregation number and orientational discrimination of coiled-coil protein domains. Hydrogels formed from a triblock artificial protein bearing dissimilar helical coiled-coil end domains (P and A) erode more than one hundredfold slower than hydrogels formed from those bearing the same end domains (either P or A). The reduced erosion rate is a consequence of the fact that looped chains are suppressed because P and A tend not to associate with each other. Thus, the erosion rate can be tuned over several orders of magnitude in artificial protein hydrogels, opening the door to diverse biomedical applications.", "date": "2006-02", "date_type": "published", "publication": "Nature Materials", "volume": "5", "number": "2", "publisher": "Nature Publishing Group", "pagerange": "153-158", "id_number": "CaltechAUTHORS:20150114-155726855", "issn": "1476-1122", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150114-155726855", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1038/nmat1573", "primary_object": { "basename": "nmat1573-s1.pdf", "url": "https://authors.library.caltech.edu/records/hcbzz-2vn02/files/nmat1573-s1.pdf" }, "resource_type": "article", "pub_year": "2006", "author_list": "Shen, Wei; Zhang, Kechun; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4ncj4-q7m59", "eprint_id": 4675, "eprint_status": "archive", "datestamp": "2023-08-22 04:51:44", "lastmod": "2023-10-16 17:52:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Olsen-A-P", "name": { "family": "Olsen", "given": "Adam P." } }, { "id": "Flagan-R-C", "name": { "family": "Flagan", "given": "Richard C." }, "orcid": "0000-0001-5690-770X" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Single-particle levitation system for automated study of homogeneous solute nucleation", "ispublished": "pub", "full_text_status": "public", "keywords": "electrostatic devices; nucleation; crystal growth from solution; humidity; chemical potential; humidity control; automation", "note": "\u00a92006 American Institute of Physics \n\n(Received 3 April 2006; accepted 13 May 2006; published online 5 July 2006) \n\nThis work was funded by the National Science Foundation (DMR-0505393 and the MRSEC Program under award DMR-0080065). The authors would also like to thank Professor Gary Lorden of Caltech for discussions regarding statistical analysis, and Professor Bill Bridges of Caltech for assistance in designing the optics for collection of Mie scattering.", "abstract": "We present an instrument that addresses two critical requirements for quantitative measurements of the homogeneous crystal nucleation rate in supersaturated aqueous solution. First, the need to perform repeated measurements of nucleation incubation times is met by automating experiments to enable programmable cycling of thermodynamic conditions. Second, the need for precise and robust control of the chemical potential in supersaturated aqueous solution is met by implementing a novel technique for regulating relative humidity. The apparatus levitates and weighs micron-sized samples in an electric field, providing access to highly supersaturated states. We report repeated observations of the crystal nucleation incubation time in a supersaturated aqueous sodium chloride droplet, from which we infer the nucleation rate.", "date": "2006-01", "date_type": "published", "publication": "Review of Scientific Instruments", "volume": "77", "number": "7", "publisher": "Review of Scientific Instruments", "pagerange": "Art. No. 073901", "id_number": "CaltechAUTHORS:OLSrsi06", "issn": "0034-6748", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:OLSrsi06", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1063/1.2212945", "primary_object": { "basename": "OLSrsi06.pdf", "url": "https://authors.library.caltech.edu/records/4ncj4-q7m59/files/OLSrsi06.pdf" }, "resource_type": "article", "pub_year": "2006", "author_list": "Olsen, Adam P.; Flagan, Richard C.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8ktdn-atr05", "eprint_id": 108363, "eprint_status": "archive", "datestamp": "2023-08-19 17:11:43", "lastmod": "2023-10-23 16:58:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Prabhutendolkar-Anuja", "name": { "family": "Prabhutendolkar", "given": "Anuja" } }, { "id": "Liu-Xiangli", "name": { "family": "Liu", "given": "Xiangli" } }, { "id": "Mathias-Errol-V", "name": { "family": "Mathias", "given": "Errol V." } }, { "id": "Ba-Yong", "name": { "family": "Ba", "given": "Yong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julie A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Synthesis of Chlorambucil-Tempol Adduct and its Delivery using Fluoroalkyl Double-Ended Poly (Ethylene Glycol) Micelles", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Chlorambucil, EPR, NMR, R_f-PEG, Tempol", "note": "\u00a9 2006 Informa Healthcare. \n\nReceived 20 Aug 2005, Accepted 18 Nov 2005, Published online: 10 Oct 2008. \n\nThis project is supported by NSF grant award #0351848. Thanks\nto the Department of Defense for funding the EPR spectrometer under grant d20030904hsi. Thanks to Dr. Y. Mao for his assistance in the EPR experiments.", "abstract": "In our pursuit to find potent anticancer drugs, we have covalently bonded free radical tempol to chlorambucil giving a chlorambucil-tempol (CT) adduct in which both of the anticancer active sites in tempol and chlorambucil were left intact. Analysis using NMR, Maldi-TOF, and EPR verified the designed chemical structure. Because the CT adduct is more hydrophobic than chlorambucil, its delivery also was investigated using fluoroalkyl double-ended poly (ethylene glycol) (R_f-PEG) micelles. Results from EPR spectra and\u00b9\u2079 F and\u00b9 H NMR spin lattice relaxation times show that the R_f-PEG micelles are able to encapsulate CT into the R_f cores of the micelles.", "date": "2006-01", "date_type": "published", "publication": "Drug Delivery", "volume": "13", "number": "6", "publisher": "Informa UK Limited", "pagerange": "433-440", "id_number": "CaltechAUTHORS:20210309-105356346", "issn": "1071-7544", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210309-105356346", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0351848" }, { "agency": "Department of Defense", "grant_number": "d20030904hsi" } ] }, "doi": "10.1080/10717540600559452", "resource_type": "article", "pub_year": "2006", "author_list": "Prabhutendolkar, Anuja; Liu, Xiangli; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ydk7m-9p985", "eprint_id": 103334, "eprint_status": "archive", "datestamp": "2023-08-19 16:21:04", "lastmod": "2023-10-20 15:56:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tae-Giyoong", "name": { "family": "Tae", "given": "Giyoong" }, "orcid": "0000-0001-9513-8093" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Hubbell-J-A", "name": { "family": "Hubbell", "given": "Jeffrey A." }, "orcid": "0000-0003-0276-5456" } ] }, "title": "Sustained release of human growth hormone from in situ forming hydrogels using self-assembly of fluoroalkyl-ended poly(ethylene glycol)", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2005 Elsevier Ltd. \n\nReceived 14 September 2004; accepted 17 January 2005. \n\nWe thank the National Hormone & Pituitary Program of National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and A.F. Parlow for providing human growth hormone. We gratefully acknowledge support from the Keck Discovery Fund and the Center for the Science and Engineering of Materials (an NSF MRSEC DMR-0080065) at Caltech.", "abstract": "Poly(ethylene glycol)s modified with fluorocarbon end groups are capable of in situ transition from an injectable liquid to a viscoelastic hydrogel by hydrophobic interaction of the end groups; this class of materials is useful for a variety of biomedical applications, including sustained protein release. The hydrogel state can be transformed into an injectable state by the addition of a toxicologically acceptable organic solvent, such as N-methyl pyrrolidone; after injection, this solution quickly returns to a gel state by diffusion of the water-miscible organic solvent into the surrounding environment. In vitro characterization of sustained release of human growth hormone (hGH) using this injectable depot shows that hGH remains stable inside the hydrogel formed, and demonstrates more than 2 weeks of prolonged release of hGH complexed with Zn\u00b2\u207a ions without protein aggregation or initial burst.", "date": "2005-09", "date_type": "published", "publication": "Biomaterials", "volume": "26", "number": "25", "publisher": "Elsevier", "pagerange": "5259-5266", "id_number": "CaltechAUTHORS:20200519-170818018", "issn": "0142-9612", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200519-170818018", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "W. M. Keck Foundation" }, { "agency": "NSF", "grant_number": "DMR-0080065" } ] }, "doi": "10.1016/j.biomaterials.2005.01.042", "resource_type": "article", "pub_year": "2005", "author_list": "Tae, Giyoong; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/v7exh-rj980", "eprint_id": 87988, "eprint_status": "archive", "datestamp": "2023-08-19 16:14:37", "lastmod": "2024-01-14 20:28:31", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Scruggs-N-R", "name": { "family": "Scruggs", "given": "Neal" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Liquid crystalline gels self-assembled from block copolymers", "ispublished": "unpub", "full_text_status": "public", "keywords": "liquid crystal, gel, nematic, self-assembly, block copolymer, display", "note": "\u00a9 2005 Society of Photo-Optical Instrumentation Engineers (SPIE).\n\nPublished - 59360H.pdf
", "abstract": "Self-assembly of coil-SGLCP-coil block copolymers provides a route to model liquid crystalline (LC) gels in concentrations ranging from bulk polymer to gels with as little as 5 wt % polymer in a small-molecule LC host. Triblock copolymers with LC-phobic endblocks associate in a nematic liquid crystal to create crosslinks. An SGLCP midblock allows for solubilization of the network. These materials have a precisely tailored network structure ideal for comparison to theory1 of liquid crystalline elastomers. In addition, the gel responds readily to external fields since the concentration of polymer can be relatively low. In this report we discuss rheological measurements that demonstrate gelation at low polymer concentrations. We show that the association of the PS blocks at low concentration is driven by the presence of the SGLCP, rather than incompatibility between PS and 5CB. We then discuss the alignment of the gels via shear, magnetic fields, electric fields, and alignment surfaces. Finally, we present results on a distinctive striped texture observed in aligned gels when subjected to an applied electric field or normal force. The exceptional electro-optic and mechano-optic responsiveness of these gels coupled with thermally reversible gelation suggests they would be ideal candidates for use in large-area printable display technology.", "date": "2005-08-20", "date_type": "published", "publisher": "Society of Photo-optical Instrumentation Engineers (SPIE)", "place_of_pub": "Bellingham, WA", "pagerange": "Art. No. 59360H", "id_number": "CaltechAUTHORS:20180718-165218339", "isbn": "0819459410", "book_title": "Liquid Crystals IX", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180718-165218339", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Khoo-Iam-Choo", "name": { "family": "Khoo", "given": "Iam-Choo" } } ] }, "doi": "10.1117/12.618477", "primary_object": { "basename": "59360H.pdf", "url": "https://authors.library.caltech.edu/records/v7exh-rj980/files/59360H.pdf" }, "resource_type": "book_section", "pub_year": "2005", "author_list": "Verduzco, Rafael; Scruggs, Neal; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/q7qd3-x6h46", "eprint_id": 79278, "eprint_status": "archive", "datestamp": "2023-08-19 16:12:51", "lastmod": "2023-10-26 14:45:37", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Auad-M-L", "name": { "family": "Auad", "given": "Maria L." } }, { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Rendon-S", "name": { "family": "Rendon", "given": "Stanley" } }, { "id": "Burghardt-W-R", "name": { "family": "Burghardt", "given": "Wesley R." } }, { "id": "Yoon-Kyunghwan", "name": { "family": "Yoon", "given": "Kyunghwan" } } ] }, "title": "Effect of Mesophase Order on the Dynamics of Side Group Liquid Crystalline Polymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2005 American Chemical Society.\n\nReceived 15 March 2005\nPublished online 16 July 2005\nPublished in print 1 August 2005\n\nWe gratefully acknowledge financial support from the Air Force Office of Scientific Research (AFOSR)-LC MURI (f4962-97-1-0014), Fundaci\u00f3n Antorchas (Argentina), CONICET (Argentina), and the National Science Foundation (DMI-0132519). X-ray scattering experiments were conducted at the DuPont\u2212Northwestern\u2212Dow Collaborative Access Team (DND-CAT) Synchrotron Research Center located at Sector 5 of the Advanced Photon Source of Argonne National Laboratory. DND-CAT is supported by the E.I. DuPont de Nemours & Co., the Dow Chemical Company, and the National Science Foundation through Grant DMR-9304725 and the State of Illinois through the Department of Commerce and the Board of Higher Education Grant IBHE HECA NWU 96. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Basic Energy Sciences, Office of Energy Research, under Contract No. W-31-102-Eng-38.\n\nSupplemental Material - ma050551fsi20050608_013004.pdf
", "abstract": "Rheology and X-ray scattering were employed to probe the viscoelastic properties and structural transitions of model cyano-biphenyl-based side-group liquid\u2212crystalline polymers (SGLCPs) with molecular weights ranging from 91 to 1900 kg/mol. Temperature-dependent rheological data show a rapid change in dynamics over a small temperature range. Small-angle X-ray scattering reveals these changes to be associated with an isotropic to smectic transition with an appreciable biphasic region. The presence of a biphasic region is attributed to inhomogeneity in chain structure resulting from incomplete attachment of mesogens to every monomeric unit in the SGLCP polymer. While isotropic and smectic phase data may be separately time\u2212temperature shifted to create master curves for the individual phases, we argue against attempts to achieve superposition between the two phases in the high-frequency regime, since smectic ordering may not simply slow the dynamics but also increase the modulus of the sample. Molecular weight has a strong influence on rheology in the isotropic phase, where an entanglement plateau emerges; however, the smectic-phase rheology is dominated by the layer structure and is fairly insensitive to molecular weight.", "date": "2005-08-09", "date_type": "published", "publication": "Macromolecules", "volume": "38", "number": "16", "publisher": "American Chemical Society", "pagerange": "6946-6953", "id_number": "CaltechAUTHORS:20170724-070313798", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-070313798", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "f4962-97-1-0014" }, { "agency": "Fundaci\u00f3n Antorchas" }, { "agency": "Consejo Nacional de Investigaciones Cient\u00edficas y T\u00e9cnicas (CONICET)" }, { "agency": "NSF", "grant_number": "DMI-0132519" }, { "agency": "E.I. DuPont de Nemours & Co." }, { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "DMR-9304725" }, { "agency": "Illinois Department of Commerce", "grant_number": "IBHE HECA NWU 96" }, { "agency": "Department of Energy (DOE)", "grant_number": "W-31-102-Eng-38" }, { "agency": "Illinois Board of Higher Education" } ] }, "doi": "10.1021/ma050551f", "primary_object": { "basename": "ma050551fsi20050608_013004.pdf", "url": "https://authors.library.caltech.edu/records/q7qd3-x6h46/files/ma050551fsi20050608_013004.pdf" }, "resource_type": "article", "pub_year": "2005", "author_list": "Auad, Maria L.; Kempe, Michael D.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/5k3qv-qjf56", "eprint_id": 104551, "eprint_status": "archive", "datestamp": "2023-08-19 16:03:57", "lastmod": "2023-10-20 20:36:10", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Burghardt-W-R", "name": { "family": "Burghardt", "given": "Wesley R." } }, { "id": "Brown-E-F", "name": { "family": "Brown", "given": "Eric F." } }, { "id": "Auad-M-L", "name": { "family": "Auad", "given": "Maria Lujan" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Molecular orientation of a commercial thermotropic liquid crystalline polymer in simple shear and complex flow", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Shear Rate, Molecular Orientation, Liquid Crystalline Polymer, Normal Stress Difference, Anisotropy Factor", "note": "\u00a9 Springer-Verlag 2004. \n\nReceived: 15 June 2004. Accepted: 14 October 2004. Published online: 2 December 2004. \n\nThis work was funded by the Air Force Office of Scientific Research MURI on liquid crystals (Grant F49620-97) and by NSF grant DMI-0099542. We gratefully thank A.D. Gotsis for providing the Vectra B polymer. Portions of this work were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) Synchrotron Research Center located at Sector 5 of the Advanced Photon Source. DND-CAT is supported by E.I. DuPont de Nemours & Co., the Dow Chemical Company, the National Science Foundation through Grant DMR-9304725, and the State of Illinois through Department of Commerce and Board of Higher Education Grant IBHE HECA NWU 96. Use of the Advanced Photon Source was supported by the US Department of Energy, Basic Energy Sciences, Office of Energy Research, under Contract No. W-31-102-Eng-38.", "abstract": "In-situ X-ray scattering methods have been used to measure the average degree of molecular orientation in the commercial thermotropic copolyesteramide, Vectra B. Experiments were conducted in both homogeneous shear flow and in extrusion-fed channel flows that provided mixed shear/extensional deformations. In the channel flows, extension has a dramatic effect on the average orientation state in the vicinity of stagnation points or expansions/contractions in cross-sectional area. Of particular note, a temporary increase and subsequent decay in orientation observed in a 4:1 slit-contraction flow provides additional indirect evidence supporting the hypothesis that Vectra B exhibits director tumbling. This is consistent with results from other fully aromatic copolyesters but contrasts with findings in \"model\" thermotropes incorporating flexible spacers. Thus, it seems that the stiffer backbone of commercial main chain LCPs is the main feature which, apparently, leads to tumbling. Measurements of average molecular orientation in transient shear flows show some connections with the corresponding mechanical response, but fail to show the distinctive characteristics that have previously been associated with either tumbling or aligning in LCPs using similar procedures. These experiments might be adversely affected by the comparatively slow rate of data acquisition, which leads to lengthy experiments in which the sample is more prone to degradation.", "date": "2005-07", "date_type": "published", "publication": "Rheologica Acta", "volume": "44", "number": "5", "publisher": "Springer", "pagerange": "446-456", "id_number": "CaltechAUTHORS:20200723-174403394", "issn": "0035-4511", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200723-174403394", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "F49620-97" }, { "agency": "NSF", "grant_number": "DMI-0099542" }, { "agency": "E. I. DuPont de Nemours and Company, Inc." }, { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "DMR-9304725" }, { "agency": "Illinois Department of Commerce", "grant_number": "IBHE HECA NWU 96" }, { "agency": "Illinois Board of Higher Education" }, { "agency": "Department of Energy (DOE)", "grant_number": "W-31-102-Eng-38" } ] }, "doi": "10.1007/s00397-004-0424-1", "resource_type": "article", "pub_year": "2005", "author_list": "Burghardt, Wesley R.; Brown, Eric F.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/aaf1c-jwa53", "eprint_id": 53282, "eprint_status": "archive", "datestamp": "2023-08-19 15:45:20", "lastmod": "2023-10-19 14:43:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Wei", "name": { "family": "Shen", "given": "Wei" } }, { "id": "Lammertink-R-G-H", "name": { "family": "Lammertink", "given": "Rob G. H." } }, { "id": "Sakata-J-K", "name": { "family": "Sakata", "given": "Jill K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Assembly of an Artificial Protein Hydrogel through Leucine Zipper Aggregation and Disulfide Bond Formation", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2005 American Chemical Society\n\nReceived August 11, 2004; Revised Manuscript Received February 3, 2005\n\nThe authors acknowledge the NSF Center for the Science and Engineering of Materials for financial support.", "abstract": "We present a strategy to stabilize artificial protein hydrogels through covalent bond formation following physical association of terminal leucine zipper domains. Artificial proteins consisting of two terminal leucine zipper domains and a random coil central domain form transient networks above a certain concentration, but the networks dissolve when placed in excess buffer. Engineering of a cysteine residue into each leucine zipper domain allows formation of disulfide bonds templated by leucine zipper aggregation. Circular dichroism spectra show that the zipper domains remain helical after cysteine residues and disulfide bonds are introduced. Asymmetric placement of the cysteine residues in the leucine zipper domains suppresses intramolecular disulfide bonds and creates linked \"multichains\" composed of ca. 9 protein chains on average, as determined by multiangle light scattering measurements. These \"multichains\" act as the building units of the physical network formed by leucine zipper aggregation. The increased valency of the building units stabilizes the hydrogels in open solutions, while the physical nature of their association allows the reversibility of gelation to be retained. The gel networks dissolve at pH 12.2, where the helicity of the leucine zipper domains is reduced by ca. 90%, and re-form upon acidification. The hydrogels show anisotropic swelling when anchored on aminated surfaces and may find applications in tissue engineering, controlled release, and microarray technologies on the basis of their stability, reversibility, and swelling behavior.", "date": "2005-05-03", "date_type": "published", "publication": "Macromolecules", "volume": "38", "number": "9", "publisher": "American Chemical Society", "pagerange": "3909-3916", "id_number": "CaltechAUTHORS:20150120-120951540", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150120-120951540", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/ma048348s", "resource_type": "article", "pub_year": "2005", "author_list": "Shen, Wei; Lammertink, Rob G. H.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ydhp4-yjs44", "eprint_id": 79283, "eprint_status": "archive", "datestamp": "2023-08-19 14:43:52", "lastmod": "2023-10-26 14:45:59", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kumaraswamy-G", "name": { "family": "Kumaraswamy", "given": "Guruswamy" } }, { "id": "Verma-R-K", "name": { "family": "Verma", "given": "Ravi K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Yeh-Fengji", "name": { "family": "Yeh", "given": "Fengji" } }, { "id": "Hsiao-B-S", "name": { "family": "Hsiao", "given": "Benjamin S." } } ] }, "title": "Shear-Enhanced Crystallization in Isotactic Polypropylene. In-Situ Synchrotron SAXS and WAXD", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2004 American Chemical Society. \n\nReceived 4 December 2003. Published online 27 October 2004. Published in print 1 November 2004. \n\nSupport for this research was provided by the NSF (DMR-9901403 and DMR-0216491). X-ray experiments were performed at the National Synchrotron Light Source, Brookhaven National Laboratory, which is supported by the Department of Energy, Division of Materials Sciences (DE-AC02-98CH10886 and DE-FG02-99ER45760). We are very grateful to Prof. Buckley Crist for detailed comments on the manuscript.\n\nSupplemental Material - ma035840nsi20041021_045213.pdf
", "abstract": "In-situ synchtrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) are used to follow the isothermal crystallization (lamellar thickness, crystallinity, orientation, and parent-to-daughter ratio) of a polydisperse isotactic polypropylene subjected to \"short term shearing\" as a function of imposed shear stress, shearing duration, and crystallization temperature. The X-ray data are interpreted in view of the real-space morphological information from ex-situ microscopy. Under \"mild\" shearing conditions (shear stress less than a critical value and shearing duration less than a critical time), needlelike nuclei are induced during shear but are so far apart that crystallites splay substantially as they grow to form somewhat distorted spherulites; the X-ray results show weakly oriented growth on a time scale that is rapid compared to quiescent crystallization and show that the orientation distribution broadens as crystallization progresses. Stronger shearing leads to the elaboration of these nuclei into threadlike structures that template the formation of highly oriented crystals with fiberlike orientation. The parent-to-daughter ratio is influenced by both temperature and flow. As expected, increasing the crystallization temperature leads to fewer daughter crystals relative to the parents. Shear also enhances the formation of parents relative to daughters:\u2009 as parent crystals form with their chain axis along the flow direction, the epitaxial daughter crystals have their chain axis in an unfavorable direction, perpendicular to the flow.", "date": "2004-11-30", "date_type": "published", "publication": "Macromolecules", "volume": "37", "number": "24", "publisher": "American Chemical Society", "pagerange": "9005-9017", "id_number": "CaltechAUTHORS:20170724-073123746", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-073123746", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9901403" }, { "agency": "NSF", "grant_number": "DMR-0216491" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-98CH10886" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-99ER45760" } ] }, "doi": "10.1021/ma035840n", "primary_object": { "basename": "ma035840nsi20041021_045213.pdf", "url": "https://authors.library.caltech.edu/records/ydhp4-yjs44/files/ma035840nsi20041021_045213.pdf" }, "resource_type": "article", "pub_year": "2004", "author_list": "Kumaraswamy, Guruswamy; Verma, Ravi K.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8px0k-xe714", "eprint_id": 79290, "eprint_status": "archive", "datestamp": "2023-08-19 14:41:44", "lastmod": "2023-10-26 14:46:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Lal-Jyotsana", "name": { "family": "Lal", "given": "Jyotsana" } } ] }, "title": "Chain Anisotropy of Side-Group Liquid Crystalline Polymers in Nematic Solvents", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2004 American Chemical Society. \n\nReceived 17 June 2003. Published online 22 October 2004. Published in print 1 November 2004. \n\nThe authors acknowledge financial support from the AFOSR LC-MURI (f4962-97-1-0014) and the ARCS foundation. We thank Neal Scruggs and Rafael Verduzco for help with the neutron scattering experiments and Ed Lang from IPNS for helping with the SANS setup.", "abstract": "We demonstrate a method for measuring the anisotropy of a side group liquid crystalline polymer (SGLCP) in a perdeuterated nematic solvent using small-angle neutron scattering. In this system scattering originates from both the polymer backbone and the large pendant side groups, causing the measured anisotropy to vary with molecular weight. Since it is the backbone anisotropy that is of interest, we show how to mathematically account for scattering due to the side groups. Using a molecular weight series of SGLCPs that have an oblate conformation, this method yields a constant ratio of the backbone radii independent of molecular weight and spacer length.", "date": "2004-11-16", "date_type": "published", "publication": "Macromolecules", "volume": "37", "number": "23", "publisher": "American Chemical Society", "pagerange": "8730-8738", "id_number": "CaltechAUTHORS:20170724-093120654", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-093120654", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "f4962-97-1-0014" }, { "agency": "ARCS Foundation" } ] }, "doi": "10.1021/ma034825f", "resource_type": "article", "pub_year": "2004", "author_list": "Kempe, Michael D.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0trky-25w95", "eprint_id": 79302, "eprint_status": "archive", "datestamp": "2023-08-19 13:36:56", "lastmod": "2023-10-26 14:47:18", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Ober-Christopher K.", "name": { "family": "Ober", "given": "Christopher K." } }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "Steven D." } } ] }, "title": "Synthesis and Phase Behavior of Side-Group Liquid Crystalline Polymers in Nematic Solvents", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2004 American Chemical Society. \n\nReceived 17 June 2003. Published online 15 April 2004. Published in print 1 May 2004. \n\nThe authors acknowledge financial support from the AFOSR LC-MURI (f4962-97-1-0014) and the ARCS foundation. We thank Abelardo Bourbois for help with the refractive index measurements.", "abstract": "A model system of side-group liquid crystalline polymers (SGLCPs) with systematically varied molecular weight (from 78 to 420 kg/mol; PDI \u2264 1.16) and spacer length (8\u221212 atoms long) was prepared by polymer analogous synthesis. Matching the structure of the mesogenic units to that of the nematic solvent produced excellent solubility, even at molecular weights an order of magnitude greater than in prior literature on SGLCP solutions. Addition of up to 10 wt % polymer did not affect the ordinary and extraordinary refractive indices of the nematic host (4-pentyl-4'-cyanobiphenyl, 5CB), indicating that the order parameter was not significantly affected by the polymer.", "date": "2004-05-18", "date_type": "published", "publication": "Macromolecules", "volume": "37", "number": "10", "publisher": "American Chemical Society", "pagerange": "3569-3575", "id_number": "CaltechAUTHORS:20170724-112902051", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-112902051", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "f4962-97-1-0014" }, { "agency": "ARCS Foundation" } ] }, "doi": "10.1021/ma0348268", "resource_type": "article", "pub_year": "2004", "author_list": "Kempe, Michael D.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/gzbpn-rgb82", "eprint_id": 56638, "eprint_status": "archive", "datestamp": "2023-08-19 13:10:58", "lastmod": "2023-10-23 15:39:17", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael D." } }, { "id": "Scruggs-N-R", "name": { "family": "Scruggs", "given": "Neal R." } }, { "id": "Verduzco-R", "name": { "family": "Verduzco", "given": "Rafael" } }, { "id": "Lal-Jyotsana", "name": { "family": "Lal", "given": "Jyotsana" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Self-assembled liquid-crystalline gels designed from the bottom up", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2004 Nature Publishing Group.\n\nReceived 9 October 2003; Accepted 8 January 2004; Published online 15 February 2004.\n\nThe authors acknowledge financial support from the United States Air Force Office of Scientific Research Liquid Crystal Multidisciplinary Research Program of the University Research Initiative (LC-MURI) (f4962-97-1-0014), the ARCS Foundation, the United States National Science Foundation Department of Materials Research (DMR-0216491), and the United States National Defense Science and Engineering Graduate (NDSEG) Fellowship. We would like to thank Steven Smith of Proctor and Gamble for providing us with 1,2-polybutadiene samples.", "abstract": "Liquid crystals are often combined with polymers to influence the liquid crystals' orientation and mechanical properties, but at the expense of reorientation speed or uniformity of alignment. We introduce a new method to create self-assembled nematic liquid-crystal gels using an ABA triblock copolymer with a side-group liquid-crystalline midblock and liquid-crystal-phobic endblocks. In contrast to in situ polymerized networks, these physical gels are homogeneous systems with a solubilized polymer network giving them exceptional optical uniformity and well-defined crosslink density. Furthermore, the unusually high-molecular-weight polymers used allow gels to form at lower concentrations than previously accessible. This enables these gels to be aligned by surface anchoring, shear, or magnetic fields. The high content of small-molecule liquid crystal (\u226595%) allows access to a regime of fast reorientation dynamics.", "date": "2004-03", "date_type": "published", "publication": "Nature Materials", "volume": "3", "number": "3", "publisher": "Nature Publishing Group", "pagerange": "177-182", "id_number": "CaltechAUTHORS:20150414-131116182", "issn": "1476-1122", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150414-131116182", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "f4962-97-1-0014" }, { "agency": "ARCS Foundation" }, { "agency": "NSF", "grant_number": "DMR-0216491" }, { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" } ] }, "doi": "10.1038/nmat1074", "resource_type": "article", "pub_year": "2004", "author_list": "Kempe, Michael D.; Scruggs, Neal R.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7mq46-4db11", "eprint_id": 108367, "eprint_status": "archive", "datestamp": "2023-08-19 12:51:09", "lastmod": "2023-10-23 16:58:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Schwartz-Daniel-M", "name": { "family": "Schwartz", "given": "Daniel M." } }, { "id": "Sandstedt-Christian-A", "name": { "family": "Sandstedt", "given": "Christian A." } }, { "id": "Chang-Shiao-H", "name": { "family": "Chang", "given": "Shiao H." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julie A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "Robert H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Light-Adjustable Lens: Development of in Vitro Nomograms", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2004 American Ophthalmological Society. \n\nThis work is supported by grant 2R44EY012181-02 from the National Eye Institute. The authors state that they have a proprietary interest in the product described in this article.\n\nPublished - tao102pg067.pdf
", "abstract": "Purpose: To determine whether digital spatial intensity patterns can be developed to effect precise in vitro correction of myopic, hyperopic, and astigmatic refractive errors in a silicone light-adjustable lens (LAL). Also, to determine whether a new spatial intensity pattern for \"lock-in\" is effective in vitro. \n\nMethods: A digital interferometer/irradiation system was developed to irradiate LALs and measure the power change following irradiation. Light-adjustable lenses were mounted into a wet cell maintained at 35.0 \u00b1 0.5\u00b0C (simulated ocular temperature) and allowed to equilibrate for a minimum of 2 hours. Ultraviolet light was then applied with spatial light intensity patterns to correct hyperopia, myopia, and astigmatism. Light-adjustable lenses were also treated to effect lock-in with a separate spatial light intensity pattern. Treated lenses were characterized for power change and optical quality. In the case of lock-in, exhaustive chemical extraction was also performed to determine the percentage of remaining macromer. \n\nResults: Appropriate digital irradiation spatial intensity patterns were created to develop nomograms for in vitro correction of myopia, hyperopia, and astigmatism in approximate 0.25 D steps. Power changes were reproducible and did not alter optical quality of the LALs. Further, lock-in dosing of the LALs did not alter optical quality or significantly change LAL power. \n\nConclusions: In vitro nomograms have been developed for a silicone LAL that permit precise correction of myopia, hyperopia, and astigmatism. Furthermore, a spatial light intensity pattern has been devised that effects lock-in without significantly altering LAL power or optical quality.", "date": "2004", "date_type": "published", "publication": "Transactions of the American Ophthalmological Society", "volume": "102", "publisher": "American Ophthalmological Society", "pagerange": "67-74", "id_number": "CaltechAUTHORS:20210309-115036488", "issn": "1545-6110", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210309-115036488", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "2R44EY012181-02" } ] }, "pmcid": "PMC1280088", "primary_object": { "basename": "tao102pg067.pdf", "url": "https://authors.library.caltech.edu/records/7mq46-4db11/files/tao102pg067.pdf" }, "resource_type": "article", "pub_year": "2004", "author_list": "Schwartz, Daniel M.; Sandstedt, Christian A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/55sev-wjw14", "eprint_id": 79301, "eprint_status": "archive", "datestamp": "2023-08-19 12:37:31", "lastmod": "2023-10-26 14:47:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lammertink-R-G-H", "name": { "family": "Lammertink", "given": "Rob G. H." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Network Formation and Sieving Performance of Self-Assembling Hydrogels", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2003 American Chemical Society. \n\nReceived 12 November 2002. Published online 7 November 2003. Published in print 1 December 2003. \n\nThis research was supported in part by NSF (CTS-9729443 and MRSEC DMR-0080065), a postdoctoral fellowship from The Netherlands Organization for Scientific Research, NWO (R.G.H.L.) and by the W. M. Keck Foundation Fund for Discovery in Basic Medical Research at the California Institute of Technology. We thank Prof. Frank Gomez at the California State University of Los Angeles for helpful discussions.", "abstract": "Self-assembling hydrogels, consisting of aqueous solutions of poly(ethylene glycol)s end-capped with perfluorocarbon groups (Rf\u2212PEGs), were studied for their electrophoretic sieving performance. These materials form physical gels, with the end groups aggregated in hydrophobic cores. The gels display high sieving performance, expressed as a large mobility dependence on DNA size, for short double-stranded DNA fragments even at relatively low polymer concentrations (\u223c3 wt %). This interesting characteristic can be attributed to the dense packing of interconnected micelles that build up the hydrogel network. The physically connected micelles act as a permanent network on the time scale of DNA migration over the distance between micelle cores. A mobility plateau was observed for intermediate DNA sizes that were probably too large to sieve through the network of interconnected micelles and yet too small to reptate. This plateau was followed by a reptation regime for larger DNA sizes, that has similar resolving characteristics to that observed for entangled linear PEO solutions.", "date": "2003-12-02", "date_type": "published", "publication": "Macromolecules", "volume": "36", "number": "24", "publisher": "American Chemical Society", "pagerange": "9154-9161", "id_number": "CaltechAUTHORS:20170724-112901776", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-112901776", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CTS-9729443" }, { "agency": "NSF", "grant_number": "DMR-0080065" }, { "agency": "Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)" }, { "agency": "W. M. Keck Foundation" } ] }, "doi": "10.1021/ma0258253", "resource_type": "article", "pub_year": "2003", "author_list": "Lammertink, Rob G. H. and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/y0fw6-cvq79", "eprint_id": 77657, "eprint_status": "archive", "datestamp": "2023-08-19 11:50:59", "lastmod": "2023-10-25 23:20:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Ya-Dong", "name": { "family": "Zhang", "given": "Ya-Dong" } }, { "id": "Jespersen-K-G", "name": { "family": "Jespersen", "given": "Kim G." } }, { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Barlow-S", "name": { "family": "Barlow", "given": "Stephen" } }, { "id": "Kippelen-B", "name": { "family": "Kippelen", "given": "Bernard" } }, { "id": "Marder-S-R", "name": { "family": "Marder", "given": "Seth R." }, "orcid": "0000-0001-6921-2536" } ] }, "title": "Columnar Discotic Liquid-Crystalline Oxadiazoles as Electron-Transport Materials", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2003 American Chemical Society. \n\nReceived January 28, 2003. In Final Form: April 7, 2003.\nPublication Date (Web): May 10, 2003. \n\nThis material is based upon work supported in part by the STC Program of the National Science Foundation under Agreement No. DMR-0120967. We also gratefully acknowledge the NSF for a CAREER grant to B.K. and the Air Force Office of Scientific Research (through the LC MURI), the Office of Naval Research, the Defense Advanced Research Program Agency, and the National Renewable Energy Laboratory for financial support. We also thank the reviewers for helpful comments.\n\nSupplemental Material - la0341456si20030128_010056.pdf
", "abstract": "A range of discoid species with benzene or triazine cores and three (trialkoxyaryl)oxadiazole arms have been synthesized. 1,3,5-tris{5-[3,4,5-tris(octyloxy)phenyl]-1,3,4-oxadiazol-2-yl}benzene has been studied in detail; it exhibits a columnar discotic liquid-crystalline mesophase between 38 and about 210 \u00b0C. The time-of-flight electron mobility at room-temperature varies from about 10^(-3) to 10^(-4) cm^2 V^(-1) s^(-1), indicating these materials may find applications in organic electronics.", "date": "2003-08-05", "date_type": "published", "publication": "Langmuir", "volume": "19", "number": "16", "publisher": "American Chemical Society", "pagerange": "6534-6536", "id_number": "CaltechAUTHORS:20170523-104412243", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170523-104412243", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0120967" }, { "agency": "Air Force Office of Scientific Research (AFOSR)" }, { "agency": "Office of Naval Research (ONR)" }, { "agency": "Defense Advanced Research Projects Agency (DARPA)" }, { "agency": "National Renewable Energy Laboratory" } ] }, "doi": "10.1021/la0341456", "primary_object": { "basename": "la0341456si20030128_010056.pdf", "url": "https://authors.library.caltech.edu/records/y0fw6-cvq79/files/la0341456si20030128_010056.pdf" }, "resource_type": "article", "pub_year": "2003", "author_list": "Zhang, Ya-Dong; Jespersen, Kim G.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/wakd4-zxk25", "eprint_id": 1709, "eprint_status": "archive", "datestamp": "2023-08-22 00:19:24", "lastmod": "2023-10-13 22:57:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "M. D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Shear Alignment Behavior of Nematic Solutions Induced by Ultralong Side-Group Liquid Crystal Polymers", "ispublished": "pub", "full_text_status": "public", "keywords": "liquid crystal polymers; nematic liquid crystals; shear flow; velocity; molecular weight", "note": "\u00a9 2003 The American Physical Society \n\n(Received 10 October 2002; published 17 March 2003) \n\nWe thank Chris Ober and Jagdish Jethalamari for help with synthesis, Weijun Zhou for help with instrumentation, and AFOSR LC-MURI for funding for this project.\n\nPublished - KEMprl03.pdf
", "abstract": "Addition of a low concentration of a very long (430 kg/mol) side group liquid crystal polymer is shown to produce dramatic changes in the flow characteristics of a calamitic nematic liquid crystal. This polymer causes a typical flow-aligning nematic liquid crystal to align near the velocity gradient direction rather than near the velocity direction, corresponding to having a tumbling parameter lambda<\u20131, for concentrations greater than 7.5% polymer. Such flow-aligning behavior has not been reported previously in a calamitic nematic. The large molecular weight of the present polymer relative to those examined in the prior literature is responsible for these new phenomena.", "date": "2003-03-21", "date_type": "published", "publication": "Physical Review Letters", "volume": "90", "number": "11", "publisher": "American Physical Society", "pagerange": "Art. no. 115501", "id_number": "CaltechAUTHORS:KEMprl03", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KEMprl03", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)" } ] }, "doi": "10.1103/PhysRevLett.90.115501", "primary_object": { "basename": "KEMprl03.pdf", "url": "https://authors.library.caltech.edu/records/wakd4-zxk25/files/KEMprl03.pdf" }, "resource_type": "article", "pub_year": "2003", "author_list": "Kempe, M. D. and Kornfield, J. A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4aymj-3cc07", "eprint_id": 104412, "eprint_status": "archive", "datestamp": "2023-08-19 10:57:04", "lastmod": "2023-10-20 20:26:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tessier-F-J", "name": { "family": "Tessier", "given": "Frederic J." } }, { "id": "Monnier-V-M", "name": { "family": "Monnier", "given": "Vincent M." } }, { "id": "Sayre-L-M", "name": { "family": "Sayre", "given": "Lawrence M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Triosidines: novel Maillard reaction products and cross-links from the reaction of triose sugars with lysine and arginine residues", "ispublished": "pub", "full_text_status": "restricted", "keywords": "dihydroxyacetone, glycation, glyceraldehyde, glyceraldehyde-3-phosphate, tissue engineering", "note": "\u00a9 2003 Biochemical Society. \n\nReceived 26 April 2002/23 September 2002 ; accepted 14 October 2002. Published as BJ Immediate Publication 14 October 2002. \n\nWe thank Dr Marcus Glomb for his gift of argpyrimidine standard and Dr Robert Salomon (Department of Chemistry, Case Western Reserve University, OH, U.S.A.) for assistance with computerized systematic nomenclature. We also thank Drs David Sell and Tiberiu G. Mustata (Institute of Pathology, Case Western Reserve University, OH, U.S.A.) for help with determination of glyceraldehyde contaminants in commercial batches. This work was supported by a grant from the National Institute of Aging (AG 18629) and in part by the National Eye Institute (EY07099).", "abstract": "The role of the highly reactive triose sugars glyceraldehyde and glyceraldehyde-3-phosphate in protein cross-linking and other amino acid modifications during the Maillard reaction was investigated. From the incubation of glyceraldehyde with N\u03b1-acetyl-l-lysine and N\u03b1-acetyl-l-arginine, we isolated four new Maillard reaction pyridinium compounds named 'triosidines'. Two of them, 'lys-hydroxy-triosidine' {1-(5-amino-5-carboxypentyl)-3-[(5-amino-5-carboxypentylamino)methyl]-5-hydroxypyridinium} and 'arg-hydroxy-triosidine' {2-(4-amino-4-carboxybutylamino)-8-(5-amino-5-carboxypentyl)-6-hydroxy-3,4-dihydro-pyrido[2,3-d]pyrimidin-8-ium} are fluorescent, UV-active Lys\u2014Lys and Lys\u2014Arg cross-links respectively. Their structures were identified by NMR and MS. In addition, two UV-active lysine adducts, 'trihydroxy-triosidine' [1-(5-amino-5-carboxypentyl)-3,4-dihydroxy-5-(hydroxymethyl)pyridinium] and 'triosidine carbaldehyde' [1-(5-amino-5-carboxypentyl)-3-formylpyridinium] were tentatively identified by MS. All structures involve six sugar-derived carbons as part of the heterocyclic ring. Of the two novel cross-links, only arg-hydroxy-triosidine was formed by glyceraldehyde-3-phosphate, an intermediate metabolite of the glycolytic pathway. Lys-hydroxy-triosidine and arg-hydroxy-triosidine were detected in human and porcine corneas treated with glyceraldehyde. The HPLC-fluorescence identification was confirmed by MS. Triosidines were also formed from dihydroxyacetone, a widely used artificial sun-tanning agent. Triosidines are expected to be useful tools in tissue engineering, where the utilization of highly reactive sugars is needed to stabilize the loose matrix. In addition, they are expected to be present in selected biological conditions, such as on consumption of a high fructose diet, and syndromes associated with high glyceraldehyde excretion, such as Fanconi Syndrome, fructose-1,6-diphosphatase deficiency and tyrosinaemia.", "date": "2003-02-01", "date_type": "published", "publication": "Biochemical Journal", "volume": "369", "number": "3", "publisher": "Biochemical Society", "pagerange": "705-719", "id_number": "CaltechAUTHORS:20200716-141801845", "issn": "0264-6021", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200716-141801845", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "AG 18629" }, { "agency": "NIH", "grant_number": "EY07099" }, { "agency": "National Institute of Aging" }, { "agency": "National Eye Institute" } ] }, "doi": "10.1042/bj20020668", "pmcid": "PMC1223106", "resource_type": "article", "pub_year": "2003", "author_list": "Tessier, Frederic J.; Monnier, Vincent M.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7mq43-sny84", "eprint_id": 1710, "eprint_status": "archive", "datestamp": "2023-08-21 23:57:19", "lastmod": "2023-10-13 22:57:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wu-Shin-Tson", "name": { "family": "Wu", "given": "Shin-Tson" } }, { "id": "Wang-Qiong-Hua", "name": { "family": "Wang", "given": "Qiong-Hua" } }, { "id": "Kempe-M-D", "name": { "family": "Kempe", "given": "Michael D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Perdeuterated cyanobiphenyl liquid crystals for infrared applications", "ispublished": "pub", "full_text_status": "public", "keywords": "organic compounds; liquid crystal phase transformations; ferroelectric liquid crystals; permittivity; refractive index; infrared spectra", "note": "\u00a92002 American Institute of Physics. \n\n(Received 26 July 2002; accepted 18 September 2002) \n\nThe UCF group is supported by AFOSR under Contract No. F49620-01-1-0377. The authors are thankful to Dr. C. J. Wang and Vicky Wen for technical assistance.", "abstract": "Perdeuterated 4'-pentyl-4-cyanobiphenyl (D5CB) was synthesized and its physical properties evaluated and compared to those of 5CB. D5CB retains physical properties similar to those of 5CB, such as phase transition temperatures, dielectric constants, and refractive indices. An outstanding feature of D5CB is that it exhibits a much cleaner and reduced infrared absorption. Perdeuteration, therefore, extends the usable range of liquid crystals to the mid infrared by significantly reducing the absorption in the near infrared, which is essential for telecom applications.", "date": "2002-12-15", "date_type": "published", "publication": "Journal of Applied Physics", "volume": "92", "number": "12", "publisher": "Journal of Applied Physics", "pagerange": "7146-7148", "id_number": "CaltechAUTHORS:WUSjap02", "issn": "0021-8979", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WUSjap02", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1063/1.1521512", "primary_object": { "basename": "WUSjap02.pdf", "url": "https://authors.library.caltech.edu/records/7mq43-sny84/files/WUSjap02.pdf" }, "resource_type": "article", "pub_year": "2002", "author_list": "Wu, Shin-Tson; Wang, Qiong-Hua; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/mqqg2-z0e68", "eprint_id": 76849, "eprint_status": "archive", "datestamp": "2023-08-19 10:26:01", "lastmod": "2023-10-25 16:55:18", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Kumaraswamy-G", "name": { "family": "Kumaraswamy", "given": "Guruswamy" } }, { "id": "Issaian-A-M", "name": { "family": "Issaian", "given": "Ani M." } } ] }, "title": "Recent Advances in Understanding Flow Effects on Polymer Crystallization", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 1 April 2002. Date accepted 6 June 2002. Published online 19 October 2002. Published in print 1 December 2002. \n\nWe are very grateful to Dr. A. Prasad (Equistar Chemical) and Dr. R. L. Sammler (The Dow Chemical Co.) for providing the materials used in our studies. Synchrotron experiments were carried out at the beamline X27C of the National Synchrotron Light Source, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Divisions of Material Sciences and Chemical Sciences, under Contract DE-AC02-98CH10886. This work was made possible by a number of funding sources:\u2009 Financial support from Proctor and Gamble, the Cargill-NIST ATP, the Schlinger fund, and NSF (DMR9901403 and PHY99-07949) is gratefully acknowledged.", "abstract": "Molecular aspects of polymer melt rheology play an extremely strong role in governing the processing\u2212structure\u2212property relations of semicrystalline polymers, the dominant materials in the plastics industry. Recent advances in experimental apparatus and methods have revealed that the dramatic changes in crystallization kinetics and morphology induced during shear follow a kinetic pathway. The rate of formation of oriented precursors is not limited by the usual activation barrier to nucleation but instead occurs many orders of magnitude faster, at a rate that tracks the dynamics of the polymer chains in the melt. Model polymers and their binary blends have shown that the relevant melt dynamics that control formation of the oriented threadlike nuclei are those of the longest chains in the melt and that the effect of the long chains is cooperative, greatly enhanced by long chain\u2212long chain overlap. Thus, insights gained into the role of chain dynamics in the molecular mechanism of shear-enhanced crystallization may soon combine with parallel advances over the past decade regarding the dynamics of polydisperse melts to provide the underpinnings for truly predictive models of flow-enhanced crystallization of polymers.", "date": "2002-12-11", "date_type": "published", "publication": "Industrial & Engineering Chemistry Research", "volume": "41", "number": "25", "publisher": "American Chemical Society", "pagerange": "6383-6392", "id_number": "CaltechAUTHORS:20170424-105033192", "issn": "0888-5885", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170424-105033192", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-98CH10886" }, { "agency": "Proctor and Gamble" }, { "agency": "Cargill, Inc." }, { "agency": "Caltech Schlinger Fund" }, { "agency": "NSF", "grant_number": "DMR99-01403" }, { "agency": "NSF", "grant_number": "PHY99-07949" }, { "agency": "National Institute of Standards and Technology (NIST)" } ] }, "doi": "10.1021/ie020237z", "resource_type": "article", "pub_year": "2002", "author_list": "Kornfield, Julia A.; Kumaraswamy, Guruswamy; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/fmk71-5n194", "eprint_id": 77001, "eprint_status": "archive", "datestamp": "2023-08-19 10:10:20", "lastmod": "2023-10-25 17:12:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tae-Giyoong", "name": { "family": "Tae", "given": "Giyoong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Hubbell-J-A", "name": { "family": "Hubbell", "given": "Jeffrey A." } }, { "id": "Johannsmann-D", "name": { "family": "Johannsmann", "given": "Diethelm" } } ] }, "title": "Anomalous Sorption in Thin Films of Fluoroalkyl-Ended Poly(ethylene glycol)s", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 13 March 2002. Published online 17 September 2002. Published in print 1 October 2002. \n\nThis research was supported in part by a grant from NSF (CTS-9729443), a graduate fellowship from the Korean Ministry of Education (Giyoong Tae), and by the MRSEC Program of NSF (DMR-0080065).", "abstract": "Absorption, desorption and swelling behavior of polymers\nplay important roles in polymer processing and performance, ranging from issues of dimensional stability\nand permeability to controlling adhesion. Rich, nonlinear\nphenomena are associated with transient swelling and drying of glassy and semicrystalline polymers. Anomalous,\nnon-Fickian behaviors are broadly associated with the\nnonlinear effects of the penetrant on the dynamics of the\npolymers. Here we describe anomalous behavior of a\ndifferent type that is associated with a sorbent-triggered\nfirst-order phase transition. The system of interest is a\nhydrophilic, semicrystalline polymer with hydrophobic end\ngroups, placed in contact with humid air.Dueto the strong\ntendency to absorb water, the melting transition of the\ncrystallites can be induced by contact with sufficiently\nhumid air; during desorption, a sufficient supersaturation\nmustbe reached before nucleation and regrowth of crystals\noccur. This leads to very different hysteresis in the sorption isotherm and overshoot in transient sorption than has been reported previously in polymers.", "date": "2002-10-15", "date_type": "published", "publication": "Langmuir", "volume": "18", "number": "21", "publisher": "American Chemical Society", "pagerange": "8241-8245", "id_number": "CaltechAUTHORS:20170427-105022344", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170427-105022344", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CTS-9729443" }, { "agency": "Ministry of Education (Korea)" }, { "agency": "NSF", "grant_number": "DMR-0080065" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/la020255l", "resource_type": "article", "pub_year": "2002", "author_list": "Tae, Giyoong; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6jgj8-6fb56", "eprint_id": 88194, "eprint_status": "archive", "datestamp": "2023-08-19 09:59:08", "lastmod": "2024-01-14 20:29:59", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julie" }, "orcid": "0000-0001-6746-8634" }, { "id": "Clark-N-A", "name": { "family": "Clark", "given": "Noel A." } }, { "id": "Dalton-L", "name": { "family": "Dalton", "given": "Larry" } }, { "id": "Marder-S-R", "name": { "family": "Marder", "given": "Seth" } }, { "id": "Ober-Christopher K.", "name": { "family": "Ober", "given": "Chris" } }, { "id": "Palffy-Muhoray-P", "name": { "family": "Palffy-Muhoray", "given": "Peter" } }, { "id": "Perry-J-W", "name": { "family": "Perry", "given": "Joseph W." } }, { "id": "Thomas-Ned", "name": { "family": "Thomas", "given": "Ned" } }, { "id": "Walba-D-M", "name": { "family": "Walba", "given": "David M." } }, { "id": "Wu-Shin-Tson", "name": { "family": "Wu", "given": "Shin-Tson" } } ] }, "title": "New liquid crystal materials enabling revolutionary display devices", "ispublished": "unpub", "full_text_status": "public", "keywords": "analog FLC, LC elastomers, LC gels, LC block copolymers, organic laser, photobuffing, NLO, LC gratings", "note": "\u00a9 2002 Society of Photo-optical Instrumentation Engineers (SPIE).\n\nPublished - 336.pdf
", "abstract": "The Display and Beam Steering Thrust of the AFOSR Liquid Crystal MURI addressed key materials and device technology issues affecting performance of liquid crystal (LC) electro-optic (EO) devices, particularly device structures useful in information Displays and for Laser Beam Steering and Switching. Two basic themes were development of bulk LCs having high performance characteristics (nematic LCs, and chiral smectic LC devices having analog response), and development of novel LC electro-optic structures. Research on novel device structures led to advances in LC alignment and on photonic band-gap materials.", "date": "2002-08-28", "date_type": "published", "publisher": "Society of Photo-optical Instrumentation Engineers (SPIE)", "place_of_pub": "Bellingham, WA", "pagerange": "336-349", "id_number": "CaltechAUTHORS:20180724-131523915", "isbn": "9780819444622", "book_title": "Cockpit Displays IX: Displays for Defense Applications", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180724-131523915", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Hopper-D-G", "name": { "family": "Hopper", "given": "Darrel G." } } ] }, "doi": "10.1117/12.480960", "primary_object": { "basename": "336.pdf", "url": "https://authors.library.caltech.edu/records/6jgj8-6fb56/files/336.pdf" }, "resource_type": "book_section", "pub_year": "2002", "author_list": "Kornfield, Julie; Clark, Noel A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/s3asa-r5y04", "eprint_id": 79239, "eprint_status": "archive", "datestamp": "2023-08-19 09:30:58", "lastmod": "2023-10-26 14:43:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tae-Giyoong", "name": { "family": "Tae", "given": "Giyoong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Hubbell-J-A", "name": { "family": "Hubbell", "given": "Jeffrey A." } }, { "id": "Lal-Jyotsana", "name": { "family": "Lal", "given": "Jyotsana" } } ] }, "title": "Ordering Transitions of Fluoroalkyl-Ended Poly(ethylene glycol): Rheology and SANS", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 18 October 2001. Published online 27 April 2002. Published in print 21 May 2002. \n\nThis research was supported in part by a grant from NSF (CTS-9729443), a graduate fellowship from the Korean Ministry of Education (Giyoong Tae), and the MRSEC Program of NSF (DMR-0080065). This work benefitted from the use of the IPNS at Argonne National Laboratory (US DoE-BES contract W-31-109-ENG-38).", "abstract": "Aqueous solutions of associative polymers consisting of poly(ethylene glycol) (PEG) (6K or 10K g/mol) terminated at both ends with hydrophobic fluoroalkyl segments, \u2212(CH_2)_2CnF_(2n+1) (n = 6, 8, or 10), exhibit ordering transitions with increasing concentration. The hydrophobic cores of the micelle-like aggregates order into a body-centered-cubic (bcc) structure, as observed by small-angle neutron scattering. The aggregation number of the hydrophobic core N_(ag) is determined by the length of the hydrophobic end group and is insensitive to polymer concentration or temperature. Ordering is enhanced by reducing PEG length for a given end group (hence, similar N_(ag)) or by increasing end group length (larger N_(ag)) for a given PEG length. This micelle packing effect is manifested in changes in the viscoelastic properties. Specifically, the single-relaxation behavior in the dynamic moduli changes upon ordering as a new low-frequency elastic plateau appears, and in creep a linear response changes to yielding behavior.", "date": "2002-05-21", "date_type": "published", "publication": "Macromolecules", "volume": "35", "number": "11", "publisher": "American Chemical Society", "pagerange": "4448-4457", "id_number": "CaltechAUTHORS:20170720-084036432", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170720-084036432", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CTS-9729443" }, { "agency": "Ministry of Education (Korea)" }, { "agency": "NSF", "grant_number": "DMR-0080065" }, { "agency": "Department of Energy (DOE)", "grant_number": "W-31-109-ENG-38" } ] }, "doi": "10.1021/ma011809e", "resource_type": "article", "pub_year": "2002", "author_list": "Tae, Giyoong; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/zy9eh-zmh26", "eprint_id": 79236, "eprint_status": "archive", "datestamp": "2023-08-19 09:15:03", "lastmod": "2023-10-26 14:43:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Seki-Motohiro", "name": { "family": "Seki", "given": "Motohiro" } }, { "id": "Thurman-D-W", "name": { "family": "Thurman", "given": "Derek W." } }, { "id": "Oberhauser-J-P", "name": { "family": "Oberhauser", "given": "James P." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Shear-Mediated Crystallization of Isotactic Polypropylene: The Role of Long Chain\u2212Long Chain Overlap", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 30 July 2001. Published online 28 February 2002. Published in print 1 March 2002. \n\nFinancial support was provided by the National Science Foundation (DMR-9901403).", "abstract": "The role of long chains in shear-mediated crystallization was studied by in situ rheo-optical measurements and ex situ microscopic observations. To elucidate the effects of long chains, we prepared model blends in which fractionated isotactic polypropylene (iPP) (denoted L-PP) with high molecular weight (MW) and narrow molecular weight distribution was blended with a metallocene iPP (Base-PP) with lower molecular weight. The concentration of L-PP (c) was varied ranging from 0 to twice the concentration (c*) at which L-PP coils overlap. The crystallization of all blends after cessation of transient shearing was accelerated, while the quiescent crystallization kinetics were not affected by the addition of L-PP. A distinctive change in the development of birefringence after shearing was observed when the wall shear stress (\u03c3w) exceeded a critical value (\u03c3*). Below \u03c3*, irrespective of c, the birefringence after transient shearing increased gradually, reaching a small value at the end of crystallization. Above \u03c3*, a brief interval of shear induced highly oriented growth, manifested in the birefringence after cessation of flow and growing stronger and reaching a large value as crystallization proceeded. Further, the rate of growth of the birefringence exhibited a strong, nonlinear c dependence. The morphology of the skin layer showed a shish kebab type structure observed by TEM for samples subjected to stresses above \u03c3*. The number density and thickness of shish were affected by c and changed drastically at c near the overlap concentration of the long chains. This indicates that the role of long chains in shear-induced oriented crystallization is cooperative (rather than a single chain effect), enhanced by long chain\u2212long chain overlap.", "date": "2002-03-26", "date_type": "published", "publication": "Macromolecules", "volume": "35", "number": "7", "publisher": "American Chemical Society", "pagerange": "2583-2594", "id_number": "CaltechAUTHORS:20170720-083352229", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170720-083352229", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9901403" } ] }, "doi": "10.1021/ma011359q", "resource_type": "article", "pub_year": "2002", "author_list": "Seki, Motohiro; Thurman, Derek W.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1b4td-ghz27", "eprint_id": 79298, "eprint_status": "archive", "datestamp": "2023-08-19 09:07:24", "lastmod": "2023-10-26 14:46:59", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kumaraswamy-G", "name": { "family": "Kumaraswamy", "given": "Guruswamy" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Yeh-Fengji", "name": { "family": "Yeh", "given": "Fengji" } }, { "id": "Hsiao-Benjamin-S", "name": { "family": "Hsiao", "given": "Benjamin S." } } ] }, "title": "Shear-Enhanced Crystallization in Isotactic Polypropylene. 3. Evidence for a Kinetic Pathway to Nucleation", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 7 August 2001. Published online 1 February 2002. Published in print 1 February 2002. \n\nWe are grateful to Dr. A. Prasad (Equistar Chemical) for providing us with the polydisperse polymer used in this study and to Dr. R. L. Sammler (The Dow Chemical Co.) for providing us with the narrow distribution polymers. We thank Dr. Motohiro Seki (Mitsubishi Chemical Co.) for NMR tacticity determination and Dr. Markus Gahleitner (Borealis AG) for measuring the Chisso IR tacticity. Synchrotron experiments were carried out at the beamline X27C of the National Synchrotron Light Source, Brookhaven National Laboratory, which is supported by the US Department of Energy, Divisions of Material Sciences and Chemical Sciences under Contract Number DE-AC02-98CH10886. We are grateful to Dr. Weidong Liu, P. Wang, and Y. Sun for assistance with synchrotron measurements and to Prof. R. C. Flagan (Caltech) for helpful discussions and for critiquing this manuscript. Financial support from Procter and Gamble, the Cargill-NIST ATP, the Schlinger Fund, and the NSF (DMR9901403) is gratefully acknowledged.\n\nSupplemental Material - ma0114180_s1.pdf
", "abstract": "In situ rheo-optical techniques are combined with synchrotron wide-angle X-ray diffraction (WAXD) to investigate the oriented crystallization precursors that develop upon strongly shearing an isothermal melt of polydisperse isotactic polypropylene (iPP). The \"short-term shearing\" experimental protocol, developed by Janeschitz-Kriegl and co-workers, is used under conditions previously determined to induce oriented crystallite growth. Surprisingly, the time for these precursors to appear decreases with increasing temperature, tracking the melt dynamics of the polymer moleculesa behavior unanticipated by current models. Thus, nucleation proceeds via a \"nonclassical\" kinetic pathway that effectively eliminates the activation barrier for nucleation. To characterize the importance of chain length distribution for the formation of nucleation precursors, experiments were performed with model bidisperse systems containing a small percentage of high molecular weight iPP blended with lower molecular weight iPP of matched stereoregularity. Oriented crystallization was not observed for the individual components of the blend under the most extreme experimental conditions investigated, but it was readily observed for the bidisperse blend. This suggests that, under intense shear, nucleation of oriented crystallites is governed by the rheologically determined formation of a critical anisotropic configuration of polymer chains in the melt.", "date": "2002-02-26", "date_type": "published", "publication": "Macromolecules", "volume": "35", "number": "5", "publisher": "American Chemical Society", "pagerange": "1762-1769", "id_number": "CaltechAUTHORS:20170724-112028020", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-112028020", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-98CH10886" }, { "agency": "Procter and Gamble" }, { "agency": "Cargill" }, { "agency": "Schlinger Fund, Caltech" }, { "agency": "NSF", "grant_number": "DMR-9901403" }, { "agency": "National Institute of Standards and Technology (NIST)" } ] }, "doi": "10.1021/ma0114180", "primary_object": { "basename": "ma0114180_s1.pdf", "url": "https://authors.library.caltech.edu/records/1b4td-ghz27/files/ma0114180_s1.pdf" }, "resource_type": "article", "pub_year": "2002", "author_list": "Kumaraswamy, Guruswamy; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/mb8tx-4tq27", "eprint_id": 79232, "eprint_status": "archive", "datestamp": "2023-08-19 08:58:44", "lastmod": "2023-10-26 14:43:23", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Hee-Hyun", "name": { "family": "Lee", "given": "Hee Hyun" } }, { "id": "Jeong-Woon-Yong", "name": { "family": "Jeong", "given": "Woon-Yong" } }, { "id": "Kim-Jin-Kon", "name": { "family": "Kim", "given": "Jin Kon" } }, { "id": "Ihn-Kyo-Jin", "name": { "family": "Ihn", "given": "Kyo Jin" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Qi-Shuyan", "name": { "family": "Qi", "given": "Shuyan" } } ] }, "title": "Orientational Proliferation and Successive Twinning from Thermoreversible Hexagonal\u2212Body-Centered Cubic Transitions", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 31 May 2001. Published online 3 January 2002. Published in print 1 January 2002 \n\nWe acknowledge helpful discussions with Professors T. Hashimoto, T. Lodge, S. Okamoto, C. Y. Ryu, S. Sakurai and A. C. Shi. This work was supported by KOSEF (97-05-02-03-01-3), by the Applied Rheology Center governed by KOSEF (2000 G0202), by TND projects supported by the Ministry of Science and Technology (MOST) and by NSF (CTS-9729443) and AFOSR (LC MURI). Synchrotron SAXS at the PLS (3C2 and 4C1 beam lines) was supported by MOST and Pohang Iron and Steel Co. (POSCO). Vector 4111 was kindly provided by Professor C. D. Han at the University of Akron.", "abstract": "The deterministic proliferation of the orientation of hexagonally packed cylinders (HEX) from the twinned body-centered cubic (BCC) phase is investigated by synchrotron small-angle X-ray scattering (SAXS) and rheo-optical methods for di- and triblock copolymers of styrene and isoprene (SI and SIS). Repeated heating and cooling cycles starting from an initially aligned HEX produce a proliferation of cylinder orientations from successively twinned BCC states. The evolution of the orientation distribution of HEX cylinders produces a decrease in the birefringence and increase in the modulus with each successive generation. The cylinder axes of the degenerate HEX states coincide with the \u3008111\u3009 directions of the twinned BCC due to the epitaxial growth of cylinders from the twinned BCC. The distribution of the cylinder axes of the degenerate HEX states among the \u3008111\u3009 directions of the twinned BCC is found to be affected by memory of the prior HEX state, which decays with annealing time in the BCC state.", "date": "2002-01-29", "date_type": "published", "publication": "Macromolecules", "volume": "35", "number": "3", "publisher": "American Chemical Society", "pagerange": "785-794", "id_number": "CaltechAUTHORS:20170720-075310985", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170720-075310985", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Korea Science and Engineering Foundation", "grant_number": "97-05-02-03-01-3" }, { "agency": "Korea Science and Engineering Foundation", "grant_number": "2000 G0202" }, { "agency": "NSF", "grant_number": "CTS-9729443" }, { "agency": "Air Force Office of Scientific Research (AFOSR)" }, { "agency": "Pohang Iron and Steel co." }, { "agency": "Ministry of Science and Technology (Korea)" } ] }, "doi": "10.1021/ma010951c", "resource_type": "article", "pub_year": "2002", "author_list": "Lee, Hee Hyun; Jeong, Woon-Yong; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/hq9xx-q3e80", "eprint_id": 79294, "eprint_status": "archive", "datestamp": "2023-08-19 08:07:17", "lastmod": "2023-10-26 14:46:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tae-Giyoong", "name": { "family": "Tae", "given": "Giyoong" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Hubbell-J-A", "name": { "family": "Hubbell", "given": "Jeffrey A." } }, { "id": "Johannsmann-D", "name": { "family": "Johannsmann", "given": "Diethelm" } }, { "id": "Hogen-Esch-T-E", "name": { "family": "Hogen-Esch", "given": "Thieo E." } } ] }, "title": "Hydrogels with Controlled, Surface Erosion Characteristics from Self-Assembly of Fluoroalkyl-Ended Poly(ethylene glycol)", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2001 American Chemical Society. \n\nReceived 1 May 2001. Published online 31 July 2001. Published in print 1 August 2001. \n\nThis research was supported in part by a grant from NSF (CTS-9729443), a graduate fellowship from the Korean Ministry of Education (GT), and by the MRSEC Program of NSF (DMR-0080065).", "abstract": "Poly(ethylene glycol) (PEG) (M_w = 6k, 10k, and 20k g/mol) terminated at both ends by hydrophobic fluoroalkyl segments (\u2212(CH_2)_2C_nF_(2n+1), n = 6, 8, or 10) was synthesized and demonstrated to self-assemble into hydrogels with phase behavior and mechanical and erosion properties that can be systematically varied by molecular design. With increasing fluoroalkyl length relative to PEG length, the phase behavior of these polymers in aqueous solution changes from the single-phase behavior of familiar associative thickeners, to sol\u2212gel coexistence, to precipitation. For those polymers that exhibit sol\u2212gel coexistence, the equilibrium gel concentration (or swelling ratio of the gel phase) and the modulus of the gel phase are governed by the length of the PEG midblock, whereas the relaxation time is determined by the hydrophobe length. The erosion characteristics of these hydrogels correlate with their phase behavior. The gels of sol\u2212gel coexisting species exhibit surface erosion in an open system with a slow dissolution rate controlled by the end-group length; in contrast, hydrogels from polymers that show single-phase behavior exhibit bulk erosion that is relatively fast. Therefore, the molecular structure of this class of polymers produces hydrogels whose mechanical and erosion properties can be tailored for desired applications. Based on the established biocompatibility of PEG, the degree to which the characteristics of the gel phases can be tailored, and the surface erosion characteristics that can be achieved, these materials might have applications in implantable drug-release depots.", "date": "2001-08-08", "date_type": "published", "publication": "Macromolecules", "volume": "34", "number": "18", "publisher": "American Chemical Society", "pagerange": "6409-6419", "id_number": "CaltechAUTHORS:20170724-100201360", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-100201360", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CTS-9729443" }, { "agency": "Ministry of Education (Korea)" }, { "agency": "NSF", "grant_number": "DMR-0080065" } ] }, "doi": "10.1021/ma0107511", "resource_type": "article", "pub_year": "2001", "author_list": "Tae, Giyoong; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/xxptj-yzn39", "eprint_id": 103249, "eprint_status": "archive", "datestamp": "2023-08-19 07:51:49", "lastmod": "2023-10-20 15:50:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Schwartz-D-N", "name": { "family": "Schwartz", "given": "D. M." } }, { "id": "Jethmalani-J-M", "name": { "family": "Jethmalani", "given": "J. M." } }, { "id": "Sandstedt-C-A", "name": { "family": "Sandstedt", "given": "C. A." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Grubbs-R-H", "name": { "family": "Grubbs", "given": "R. H." }, "orcid": "0000-0002-0057-7817" } ] }, "title": "Post implantation adjustable intraocular lenses", "ispublished": "pub", "full_text_status": "public", "abstract": "To eliminate persistent refractive errors after cataract and phakic IOL surgery, photosensitive silicone IOLs have been developed. These IOL formulations enable precise laser adjustment of IOL power to correct spherical and toric errors post-operatively, after wound and IOL stabilization. Initial experience with these laser adjustable IOLs indicate excellent biocompatability and adjustability of more than five diopters.", "date": "2001-06", "date_type": "published", "publication": "Ophthalmology clinics of North America", "volume": "14", "number": "2", "publisher": "Elsevier", "pagerange": "339-45, viii", "id_number": "CaltechAUTHORS:20200515-153337604", "issn": "0896-1549", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200515-153337604", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2001", "author_list": "Schwartz, D. M.; Jethmalani, J. M.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/671q1-fv047", "eprint_id": 78910, "eprint_status": "archive", "datestamp": "2023-08-19 07:45:34", "lastmod": "2023-10-26 14:27:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhou-Wei-Jun", "name": { "family": "Zhou", "given": "Wei-Jun" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Burghardt-W-R", "name": { "family": "Burghardt", "given": "Wesley R." } } ] }, "title": "Shear Aligning Properties of a Main-Chain Thermotropic Liquid Crystalline Polymer", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2001 American Chemical Society. \n\nReceived October 27, 2000. Publication Date (Web): April 26, 2001. \n\nFinancial support was provided by the Air Force Office of Scientific Research Liquid Crystal-MURI (Grant F49620-97). We thank Prof. Peter Palffy-Muhoray of Kent State University for assistance with liquid crystal alignment.", "abstract": "We report the first direct, quantitative measurements of the shear aligning properties of a main-chain thermotropic liquid crystalline polymer (LCP). We find that a model thermotrope with alternating mesogen and spacer structure is of the shear aligning type throughout its nematic range. The director rotates uniformly in the shear flow toward the Leslie alignment angle as probed by in situ flow conoscopy. The Leslie alignment angle becomes progressively closer to the flow direction as temperature decreases, corresponding to a decrease of the tumbling parameter \u03bb with increasing order parameter S. Our measurements of \u03bb(S) enable direct comparison with predictions from molecular models, which predict that shear alignment prevails in the limit of flexible nematic chains. This is in direct contrast to rodlike lyotropic LCPs for which director tumbling is the rule.", "date": "2001-05-22", "date_type": "published", "publication": "Macromolecules", "volume": "34", "number": "11", "publisher": "American Chemical Society", "pagerange": "3654-3660", "id_number": "CaltechAUTHORS:20170710-150255505", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170710-150255505", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Air Force Office of Scientific Research (AFOSR)", "grant_number": "F49620-97" } ] }, "doi": "10.1021/ma0018493", "resource_type": "article", "pub_year": "2001", "author_list": "Zhou, Wei-Jun; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/tga2a-mq308", "eprint_id": 88022, "eprint_status": "archive", "datestamp": "2023-08-19 04:52:03", "lastmod": "2023-10-18 21:36:59", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kumaraswamy-G", "name": { "family": "Kumaraswamy", "given": "Guruswamy" } }, { "id": "Issaian-A-M", "name": { "family": "Issaian", "given": "Ani M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Shear-Enhanced Crystallization in Isotactic Polypropylene. 1. Correspondence between in Situ Rheo-Optics and ex Situ Structure Determination", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1999 American Chemical Society. \n\nReceived May 18, 1999; Revised Manuscript Received July 15, 1999. \nWe would like to acknowledge financial support from P&G, the Cargill-NIST ATP, NSF-DMR 9901403, and the Schlinger fund that made this project possible. One of the authors (K.G.) would like to acknowledge support from a Landau fellowship. We are very grateful to Dr. A. Prasad (Quantum Chemical) for providing us with the commercial grade polypropylene, PP8004MR (\"PP-300/6\"), for our experiments. We are grateful to Dr. R. L. Sammler (The Dow Chemical Co.) for providing us with the atactic polypropylene sample. We would also like to acknowledge help from Joanna Dodd for preliminary characterization of PP-300/6.", "abstract": "The effects of \"short term shearing\" on the subsequent crystallization of a polydisperse Ziegler\u2212Natta isotactic polypropylene are observed using in situ optical measurements and ex situ microscopy. Imposition of brief intervals of shear (0.25\u221220 s, less than a thousandth of the quiescent crystallization time) can reduce the crystallization time by 2 orders of magnitude (e.g., at 141 \u00b0C with a wall shear stress of 0.06 MPa). With increasing shearing time, the crystallization time saturates and highly anisotropic growth ensues. This transition to oriented growth correlates with changes in the transient behavior during flow and the semicrystalline morphology observed ex situ. During flow, we observe the generation of long-lived, highly oriented structures (evident in the transient birefringence) under all conditions that induce subsequent growth of highly oriented crystallites. In turn, the development of oriented crystallites observed in situ after cessation of flow correlates with development of a \"skin-core\" morphology (highly oriented skin on a spherulitic core) observed ex situ. Interestingly, the long-lived structures generated during flow appear at shorter times with increasing temperature (at fixed shear stress), the opposite of the trend one would expect on the basis of the temperature dependence of quiescent crystallization.", "date": "1999-11-02", "date_type": "published", "publication": "Macromolecules", "volume": "32", "number": "22", "publisher": "American Chemical Society", "pagerange": "7537-7547", "id_number": "CaltechAUTHORS:20180719-145939318", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180719-145939318", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Procter and Gamble" }, { "agency": "Cargill, Inc." }, { "agency": "National Institute of Standards and Technology (NIST)" }, { "agency": "NSF", "grant_number": "DMR-9901403" }, { "agency": "Schlinger Fund, Caltech" }, { "agency": "Landau fellowship" } ] }, "doi": "10.1021/ma990772j", "resource_type": "article", "pub_year": "1999", "author_list": "Kumaraswamy, Guruswamy; Issaian, Ani M.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7p5gh-nwr21", "eprint_id": 1712, "eprint_status": "archive", "datestamp": "2023-08-22 13:40:12", "lastmod": "2023-10-13 22:57:45", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kumaraswamy-G", "name": { "family": "Kumaraswamy", "given": "Guruswamy" } }, { "id": "Verma-R-K", "name": { "family": "Verma", "given": "Ravi K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Novel flow apparatus for investigating shear-enhanced crystallization and structure development in semicrystalline polymers", "ispublished": "pub", "full_text_status": "public", "keywords": "polymer melts; shear deformation; shear flow; crystallisation; channel flow; polymer structure", "note": "\u00a91999 American Institute of Physics. \n\n(Received 6 October 1998; accepted 12 January 1999) \n\nThe authors would like to acknowledge financial support from Procter & Gamble and the Schlinger fund that made this project possible. One of the authors (G.K.) would like to acknowledge support from a Landau fellowship. The authors are very grateful to Dr. A. Prasad (Equistar Chemical) for providing the commercial grade polypropylene, PP8004MR (PP-300/6), and to Dr. R. L. Sammler and Dr. C. P. Bosnyak (The Dow Chemical Company) for supplying the narrow polydispersity isotactic polypropylene (Dow developmental resin, PP-186/2.1). Dr. R. L. Sammler also gave a critical reading of the manuscript and very useful comments. Dr. G. Smedley and Professor R. C. Flagan (Caltech) gave valuable advice regarding the design of the instrument.", "abstract": "An instrument to study the effects of shearing on the crystallization process in semicrystalline polymers is described. It can impose transient stresses similar to those encountered in polymer processing and provides in situ monitoring of microstructure development during and after cessation of flow. Box-like wall shear stress profiles (rise and fall times under 50 ms with maximum wall shear stress on the order of 0.1 MPa) can be applied for controlled durations. A unique feature of our device is that it accommodates a wide variety of real-time probes of structure such as visible and infrared polarimetry and light and x-ray scattering measurements. The design also allows us to retrieve the sample for ex situ optical and electron microscopy. Data are acquired with millisecond resolution enabling us to record the extent of shear deformation of the polymer melt during the pressure pulse. Our device works with small sample quantities (as little as 5 g; each experiment takes ~ 500 mg) as opposed to the kilogram quantities required by previous instruments capable of imposing comparable deformations. This orders-of-magnitude reduction in the sample size allows us to study model polymers and new developmental resins, both of which are typically available only in gram-scale quantities. The compact design of the shear cell makes it possible to transport it to synchrotron light sources for in situ x-ray scattering studies of the evolution of the crystalline structure. Thus, our device is a valuable new tool that can be used to evaluate the crystallization characteristics of resins with experimental compositions or molecular architectures when subjected to processing-like flow conditions. We demonstrate some of the features of this device by presenting selected results on isotactic polypropylenes.", "date": "1999-04", "date_type": "published", "publication": "Review of Scientific Instruments", "volume": "70", "number": "4", "publisher": "Review of Scientific Instruments", "pagerange": "2097-2104", "id_number": "CaltechAUTHORS:KUMrsi99", "issn": "0034-6748", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUMrsi99", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1063/1.1149720", "primary_object": { "basename": "KUMrsi99.pdf", "url": "https://authors.library.caltech.edu/records/7p5gh-nwr21/files/KUMrsi99.pdf" }, "resource_type": "article", "pub_year": "1999", "author_list": "Kumaraswamy, Guruswamy; Verma, Ravi K.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/3ksgg-q4g25", "eprint_id": 103335, "eprint_status": "archive", "datestamp": "2023-08-22 13:06:23", "lastmod": "2023-10-20 15:56:18", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Saxena-S", "name": { "family": "Saxena", "given": "S." }, "orcid": "0000-0001-9098-6114" }, { "id": "Cizmeciyan-D", "name": { "family": "Cizmeciyan", "given": "D." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Solid state \u00b2H-NMR studies of segmental dynamics in polymer blends", "ispublished": "pub", "full_text_status": "restricted", "keywords": "\u00b2H-NMR; Deuterium; Glass transition", "note": "\u00a9 1998 Elsevier Science B.V. \n\nReceived 12 February 1998; revised 15 May 1998; accepted 16 May 1998.", "abstract": "Recent two-dimensional (2D) \u00b2H-NMR studies on nearly ideal mixtures are reviewed. The use of selective deuterium labeling allows the unambiguous observation of the individual segmental dynamics of each component in the blend. 2D exchange spectra provide both the mean motional rates and the motional distributions, which was necessary to discriminate among the disparate explanations of blend behavior. The components exhibit very different mean mobilities and broad mobility distributions near the glass transition. The broad macroscopic glass transition in the blends is attributed to both these two kinds of dynamic heterogeneities. The individual mean motional rates are used to define distinct glass transition temperatures, T_(g,i)* for each species, i. The separation between the T_(g,i)*,s of the two species increases with the content of the high-T_g component. The widths of their individual motional distributions also increase with the content of the high-T_g component. These two effects combine to produce the increase in both the anomalously broad glass transition and the thermorheological complexity of these blends with fraction of the high-T_g component.", "date": "1998-09", "date_type": "published", "publication": "Solid State Nuclear Magnetic Resonance", "volume": "12", "number": "2-3", "publisher": "Elsevier", "pagerange": "165-181", "id_number": "CaltechAUTHORS:20200519-170818650", "issn": "0926-2040", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200519-170818650", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1016/s0926-2040(98)00060-5", "resource_type": "article", "pub_year": "1998", "author_list": "Saxena, S.; Cizmeciyan, D.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/rpehe-5j006", "eprint_id": 88010, "eprint_status": "archive", "datestamp": "2023-08-19 02:02:43", "lastmod": "2023-10-18 21:36:10", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chen-Z-R", "name": { "family": "Chen", "given": "Z.-R." } }, { "id": "Issaian-A-M", "name": { "family": "Issaian", "given": "A. M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "S. D." } }, { "id": "Grothaus-J-T", "name": { "family": "Grothaus", "given": "J. T." } }, { "id": "Satkowski-M-M", "name": { "family": "Satkowski", "given": "M. M." } } ] }, "title": "Dynamics of Shear-Induced Alignment of a Lamellar Diblock:\u2009 A Rheo-optical, Electron Microscopy, and X-ray Scattering Study", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1997 American Chemical Society. \n\nReceived May 13, 1997; Revised Manuscript Received September 2, 1997. \n\nThis research was carried out with the support of the NSF-CTS 9421015, AFOSR-Liquid Crystals MURI, Chevron and Raychem. We thank Hans Spiess and Uli Wiesner for inspiring this work; Glenn Fredrickson, Scott Milner, Zhen-Gang Wang, Ron Larson, Frank Bates, Karen Winey, and Nitash Balsara for insightful discussions; and Richard Spontak, Steve Hudson, and Faith Morrison for valuable feedback on the manuscript.", "abstract": "In-situ rheo-optical methods are used to guide electron microscopy (TEM) and X-ray scattering (SAXS) studies of structure development during flow-induced alignment in a lamellar block copolymer melt (nearly symmetric polystyrene\u2212polyisoprene diblock, ODT \u2243 172 \u00b0C). The progress of shear-induced alignment is recorded in real-time using flow birefringence; at selected points during alignment samples are taken for ex-situ characterization by TEM and SAXS along all three axes (v, \u2207v, \u2207 \u00d7 v) of the flow geometry. Three different trajectories are examined:\u2009 perpendicular alignment and two qualitatively different routes to parallel alignment in the high-frequency regime (\u03c9 > \u03c9'_c). In general, the initial \"fast\" process not only enhances the projection of the orientation distribution that corresponds to the final state but also increases other projections of the distribution; the late-stage \"slow\" process eliminates these other projections and perfects a single alignment. For example, the highest frequency path to parallel alignment begins by transforming poorly organized regions into layers that are predominantly oriented along the parallel and transverse directions. The transition to the slow process is marked by the development of a characteristic texture in which tilt wall boundaries normal to the flow direction separate bands that form a repeating \"chevron\" pattern (layers tilted up and down about the \u2207\u00d7v axis). The coarsening of this pattern dominates the slow process, during which the transverse projection is also eliminated.", "date": "1997-11-17", "date_type": "published", "publication": "Macromolecules", "volume": "30", "number": "23", "publisher": "American Chemical Society", "pagerange": "7096-7114", "id_number": "CaltechAUTHORS:20180719-141226290", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180719-141226290", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CTS-9421015" }, { "agency": "Air Force Office of Scientific Research (AFOSR)" }, { "agency": "Chevron Corporation" }, { "agency": "Raychem" } ] }, "doi": "10.1021/ma9706743", "resource_type": "article", "pub_year": "1997", "author_list": "Chen, Z.-R.; Issaian, A. M.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/wha4d-fvm88", "eprint_id": 52310, "eprint_status": "archive", "datestamp": "2023-08-19 01:45:29", "lastmod": "2023-10-18 19:45:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chen-Zhong-Ren", "name": { "family": "Chen", "given": "Zhong-Ren" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "Steven D." } }, { "id": "Grothaus-J-T", "name": { "family": "Grothaus", "given": "Jeffrey T." } }, { "id": "Satkowski-M-M", "name": { "family": "Satkowski", "given": "Michael M." } } ] }, "title": "Pathways to Macroscale Order in Nanostructured Block Copolymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1997 American Association for the Advancement of Science.\n\nThis research was carried out with the support of\nNSF (grant CTS 9421015), the Air Force Office of\nScientific Research (Liquid Crystals MURI), Chevron,\nand Raychem.", "abstract": "Polymeric materials undergo dramatic changes in orientational order in response to dynamic processes, such as flow. Their rich cascade of dynamics presents opportunities to create and combine distinct alignments of polymeric nanostructures through processing. In situ rheo-optical measurements complemented by ex situ x-ray scattering reveal the physics of three different trajectories to macroscopic alignment of lamellar diblock copolymers during oscillatory shearing. At the highest frequencies, symmetry arguments explain the transient development of a bimodal texture en route to the alignment of layers parallel to the planes of shear. At lower frequencies, larger-scale relaxations introduce rearrangements out of the deformation plane that permit the formation of lamellae perpendicular to the shear plane. These explain the change in the character of the pathway to parallel alignment and the emergence of perpendicular alignment as the frequency decreases.", "date": "1997-08-29", "date_type": "published", "publication": "Science", "volume": "277", "number": "5330", "publisher": "American Association for the Advancement of Science", "pagerange": "1248-1253", "id_number": "CaltechAUTHORS:20141203-091201329", "issn": "0036-8075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141203-091201329", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CTS 9421015" }, { "agency": "Air Force Office of Scientific Research (AFOSR)" }, { "agency": "Chevron" }, { "agency": "Raychem" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1126/science.277.5330.1248", "resource_type": "article", "pub_year": "1997", "author_list": "Chen, Zhong-Ren; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/439bf-hnm37", "eprint_id": 88033, "eprint_status": "archive", "datestamp": "2023-08-19 01:04:26", "lastmod": "2023-10-18 21:38:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arendt-B-H", "name": { "family": "Arendt", "given": "B. H." } }, { "id": "Krishnamoorti-Ramanan", "name": { "family": "Krishnamoorti", "given": "R." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "S. D." } } ] }, "title": "Component Dynamics in Miscible Blends:\u2009 Equally and Unequally Entangled Polyisoprene/Polyvinylethylene", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1997 American Chemical Society. \n\nReceived June 21, 1996; Revised Manuscript Received December 3, 1996. \n\nWe gratefully acknowledge the support of the National Science Foundation Presidential Young Investigator Award (J.A.K.), the National Physical Science Consortium (B.H.A.), the Petroleum Research Fund administered by the American Chemical Society, Chevron, and the Caltech Consortium in Chemistry and Chemical Engineering:\u2009 E. I. du Pont de Nemours and Company, Inc. and Eastman Kodak Company.", "abstract": "Miscible blends of 1,4-polyisoprene (PIP) and polyvinylethylene (PVE) are studied using rheo-optical methods to extract the dynamics of each component in the blend. Since orientational coupling contributes to the birefringence, but not the stress, simultaneous analysis of these observables for bidisperse blends is used to determine the coupling coefficient, \u03b5. No systematic dependence of \u03b5 on composition or temperature was detected. The dynamics of the blend components extracted using the mean value of \u03b5 are in good agreement with those observed previously for equally entangled blends:\u2009 blending causes only small changes in the component entanglement molecular weights but dramatically alters the species' friction coefficients, with the dynamics of the high T_g species (PVE ) being more sensitive to both temperature and composition.", "date": "1997-02-24", "date_type": "published", "publication": "Macromolecules", "volume": "30", "number": "4", "publisher": "American Chemical Society", "pagerange": "1127-1137", "id_number": "CaltechAUTHORS:20180719-154658858", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180719-154658858", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "National Physical Science Consortium" }, { "agency": "American Chemical Society Petroleum Research Fund" }, { "agency": "Chevron Corporation" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" }, { "agency": "E. I. DuPont de Nemours and Company, Inc." }, { "agency": "Eastman Kodak Company" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/ma960901l", "resource_type": "article", "pub_year": "1997", "author_list": "Arendt, B. H.; Krishnamoorti, R.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8gaqz-mge33", "eprint_id": 88032, "eprint_status": "archive", "datestamp": "2023-08-19 01:04:18", "lastmod": "2023-10-18 21:38:21", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arendt-B-H", "name": { "family": "Arendt", "given": "B. H." } }, { "id": "Krishnamoorti-Ramanan", "name": { "family": "Krishnamoorti", "given": "R." } }, { "id": "Kannan-R-M", "name": { "family": "Kannan", "given": "R. M." } }, { "id": "Seitz-K", "name": { "family": "Seitz", "given": "K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Roovers-J", "name": { "family": "Roovers", "given": "J." } } ] }, "title": "Dynamics of Disordered Diblocks of Polyisoprene and Polyvinylethylene", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1997 American Chemical Society. \n\nReceived June 21, 1996; Revised Manuscript Received December 3, 1996. \n\nWe gratefully acknowledge the support of the National Science Foundation Presidential Young Investigator Award (J.A.K.), the National Physical Science Consortium (B.H.A.), the Caltech Summer Undergraduate Research Fellowship Program (K.S.), Chevron, and the Caltech Consortium in Chemistry and Chemical Engineering:\u2009 E. I. du Pont de Nemours and Company, Inc. and Eastman Kodak Company. We thank Dr. Fei Wang for preparing and characterizing the polymers", "abstract": "The apparent thermorheological simplicity of disordered diblocks is reconciled with the failure of time\u2212temperature superposition of corresponding miscible blends by examining the relaxation of the constituent blocks using rheo-optical techniques. Diblocks of 1,4-polyisoprene (PIP) and polyvinylethylene (PVE) are examined over a range of temperatures for two compositions (\u03c6_(PIP) = 0.25 and 0.75). Unlike blends of PIP and PVE, the block copolymers appear to obey time\u2212temperature superposition on the basis of their viscoelastic properties. However, departure from thermorheological simplicity is exposed in their stress\u2212optical behavior. In particular, the copolymer rich in the high T_g component (\u03c6_(PIP) = 0.25) shows distinct temperature dependencies for the individual blocks, in accord with the behavior of PIP/PVE blends. The block copolymer rich in the low T_g component (\u03c6_(PIP) = 0.75) is thermorheologically simple because both blocks have similar monomeric friction coefficients \u03b6_(o,PVE) \u2248 \u03b6_(o,PIP), again in accord with prior results on PIP/PVE blends. The failure of time\u2212temperature superposition in these diblocks was not previously observed because the change in \u03b6_(o,PVE)/\u03b6_(o,PIP) with temperature produces subtle changes in the overall relaxation spectrum relative to a linear chain of uniform friction.", "date": "1997-02-24", "date_type": "published", "publication": "Macromolecules", "volume": "30", "number": "4", "publisher": "American Chemical Society", "pagerange": "1138-1145", "id_number": "CaltechAUTHORS:20180719-154142453", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180719-154142453", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "National Physical Science Consortium" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "Chevron Corporation" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" }, { "agency": "E. I. DuPont de Nemours and Company, Inc." }, { "agency": "Eastman Kodak Company" } ] }, "doi": "10.1021/ma960902d", "resource_type": "article", "pub_year": "1997", "author_list": "Arendt, B. H.; Krishnamoorti, R.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/nm1eq-2bv92", "eprint_id": 86764, "eprint_status": "archive", "datestamp": "2023-08-20 04:43:26", "lastmod": "2023-10-18 20:33:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chung-Geunchang", "name": { "family": "Chung", "given": "G.-C." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "S. D." } } ] }, "title": "Compositional Dependence of Segmental Dynamics in a Miscible Polymer Blend", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1994 American Chemical Society. \n\nReceived May 19, 1994.\n\nWe gratefully acknowledge the support of the National Science Foundation Presidential Young Investigator Award (J.A.K.), Chevron, the Caltech Consortium in Chemistry and Chemical Engineering, du Pont de Nemours, Eastman Kodak, and the Petroleum Research Fund, administered by the American Chemical Society.", "abstract": "The segmental motion of each species in polyisoprene/poly(vinylethylene) (PI/PVE) miscible blends is studied at three different compositions using two-dimensional deuteron exchange NMR (2D ^2H NMR). The individual species exhibit widely different mean mobilities and broad mobility distributions near the glass transition of each blend. As the PVE content increases, both the difference in mean mobilities between the two species and the width of the mobility distribution for both components increase. The change in these two types of dynamic heterogeneity with PVE content appears to produce the anomalous broadening of the glass transition. The mean reorientational correlation times of each component can differ by 2 orders of magnitude under identical conditions. This difference can be described in terms of distinct effective glass transition temperatures, T_g*, for the two species. The separation between the two effective glass transition temperatures increases almost monotonically with PVE content, consistent with the more pronounced thermorheological complexity of blends rich in PVE. The individual T_g*'s also exhibit a different compositional dependence from that of the calorimetric T_g of the blend observed by differential scanning calorimetry (DSC). This behavior can give rise to the complex compositional dependence of individual mobilities, apparent when the mobilities are compared at the same T - T_g with respect to the DSC T_g of the blend.", "date": "1994-09-26", "date_type": "published", "publication": "Macromolecules", "volume": "27", "number": "20", "publisher": "American Chemical Society", "pagerange": "5729-5741", "id_number": "CaltechAUTHORS:20180601-160702859", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180601-160702859", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Chevron Corporation" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" }, { "agency": "E. I. DuPont de Nemours and Company, Inc." }, { "agency": "Eastman Kodak Company" }, { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1021/ma00098a030", "resource_type": "article", "pub_year": "1994", "author_list": "Chung, G.-C.; Kornfield, J. A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/p25pp-4f718", "eprint_id": 1714, "eprint_status": "archive", "datestamp": "2023-08-22 10:01:13", "lastmod": "2023-10-13 22:57:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Gupta-V-K", "name": { "family": "Gupta", "given": "Vinay K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Polarization modulation laser scanning microscopy: A powerful tool to image molecular orientation and order", "ispublished": "pub", "full_text_status": "public", "keywords": "MOLECULAR ORIENTATION; SCANNING LIGHT MICROSCOPY; IMAGE FORMING; SPATIAL RESOLUTION; POLARIZATION; OPTICAL ANISOTROPY; SENSITIVITY; LANGMUIR\u2013BLODGETT FILMS; DICHROISM", "note": "Copyright \u00a9 1994 American Institute of Physics. \n\n(Received 18 April 1994; accepted 17 May 1994) \n\nThis work was supported by Raychem, and the Caltech Consortium in Chemistry and Chemical Engineering: E. I. duPont de Nemours, Eastman Kodak, and 3M. The authors thank Dr. A. Ferencz and Professor G. Wegner at the Max-Planck-Institut-fur-Polymerforschung for providing the LB films. We also thank J. Revel at the Division of Biology at Caltech and Dr. P. Bauerschmidt at Zeiss for their support in modifying the Zeiss LSM, and Mr. A. Kratel for his contributions to the design of the polarization-modulating unit.", "abstract": "To image the orientational order in a broad class of biological and manufactured materials, a new microscope has been developed that integrates laser scanning microscopy with polarization modulation polarimetry. Polarimetry allows quantitative characterization of the molecular orientation and the degree of order through characterization of optical anisotropy. Combined with laser scanning microscopy, it is used here to image the anisotropy with high spatial resolution, sensitivity, and speed. The design of the microscope is presented; and the vast improvement in sensitivity achieved using PM-LSM over conventional polarization microscopy is illustrated by imaging the linear dichroism of ultrathin Langmuir\u2013Blodgett polymer films. PM-LSM allows imaging of the magnitude and orientation of linear dichroism in films as thin as three molecular layers (~66 \u00c5) at high resolution by rastering a diffraction limited spot of laser light across the sample. The rate of image acquisition is over 2000 pixels/s, two to three orders of magnitude faster than the previous methods of imaging optical anisotropy.", "date": "1994-09", "date_type": "published", "publication": "Review of Scientific Instruments", "volume": "65", "number": "9", "publisher": "Review of Scientific Instruments", "pagerange": "2823-2828", "id_number": "CaltechAUTHORS:GUPrsi94", "issn": "0034-6748", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:GUPrsi94", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1063/1.1144622", "primary_object": { "basename": "GUPrsi94.pdf", "url": "https://authors.library.caltech.edu/records/p25pp-4f718/files/GUPrsi94.pdf" }, "resource_type": "article", "pub_year": "1994", "author_list": "Gupta, Vinay K. and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/rfbx7-eae34", "eprint_id": 52553, "eprint_status": "archive", "datestamp": "2023-08-20 04:37:10", "lastmod": "2023-10-18 20:58:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Gupta-V-K", "name": { "family": "Gupta", "given": "V. K." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Ferencz-A", "name": { "family": "Ferencz", "given": "A." } }, { "id": "Wegner-G", "name": { "family": "Wegner", "given": "G." } } ] }, "title": "Controlling Molecular Order in \"Hairy-Rod\" Langmuir-Blodgett Films: A Polarization-Modulation Microscopy Study", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1994 American Association for the Advancement of Science.\n\nReceived 27 April 1994; accepted 27 June 1994.\n\nSupported by Raychem and the Caltech Consortium\nin Chemistry and Chemical Engineering: E. I. duPont\nde Nemours, Eastman Kodak, and 3M.", "abstract": "The interplay of molecular weight, layer thickness, and thermal annealing in controlling molecular order in ultrathin Langmuir-Blodgett films is characterized with the use of polarization-modulation laser-scanning microscopy. The degree and direction of molecular alignment can be imaged rapidly and sensitively through the magnitude and orientation of linear dichroism in Langmuir-Blodgett films of rodlike poly(phthalocyaninatosiloxane) (PcPS). Images are presented for films as thin as two molecular layers (\u223c44 angstroms). Molecular alignment along the transfer direction is much stronger for films of PcPS with \u223c25 repeat units (\u223c10 nanometers long) than for those with \u223c50 repeat units (\u223c20 nanometers long). Enhancement of alignment by thermal annealing is also much greater for PcPS-25 than PcPS-50. Intimate interaction with the substrate suppresses improvement in alignment by annealing, evident by an anomalously small increase in anisotropic absorption of the first two layers.", "date": "1994-08-12", "date_type": "published", "publication": "Science", "volume": "265", "number": "5174", "publisher": "American Association for the Advancement of Science", "pagerange": "940-942", "id_number": "CaltechAUTHORS:20141210-124151810", "issn": "0036-8075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141210-124151810", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Raychem" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" }, { "agency": "E. I. duPont de Nemours and Co." }, { "agency": "Eastman Kodak" }, { "agency": "3M" } ] }, "doi": "10.1126/science.265.5174.940", "resource_type": "article", "pub_year": "1994", "author_list": "Gupta, V. K.; Kornfield, J. A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/sgys3-wpp83", "eprint_id": 70102, "eprint_status": "archive", "datestamp": "2023-08-20 04:25:47", "lastmod": "2023-10-20 21:47:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arendt-B-H", "name": { "family": "Arendt", "given": "B. H." } }, { "id": "Kannan-R-M", "name": { "family": "Kannan", "given": "R. M." } }, { "id": "Zewail-M", "name": { "family": "Zewail", "given": "M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "S. D." } } ] }, "title": "Dynamics of each component in miscible blends of polyisoprene and polyvinylethylene", "ispublished": "pub", "full_text_status": "public", "keywords": "Polymer melt - dynamic moduli - flow birefringence - stress-optic rule - rheo-optical investigation - polymer blend", "note": "\u00a9 1994 Dr. Dietrich Steinkopff Verlag GmbH & Co.", "abstract": "The dynamics of the individual components in 1,4-polyisoprene/polyvinylethylene (PIP/PVE) miscible blends are studied using dynamic stress-optical measurements. While the homopolymers are thermorheologically simple and obey the stress-optic rule, the blends show failure of time-temperature superposition and complex stress-optic behavior. The way in which the stress-optic rule fails reveals the relaxation dynamics of each species. The dynamic modulus and complex birefringence coefficient are analyzed to infer the relaxation of each component. The entanglement molecular weight, M_e, and monomeric friction coefficient, \u03b6_0, of each species as a function of blend composition and temperature are determined from the contribution of each species to the dynamic modulus. The effect of blending on M_e of each component is small; however, its effect on \u03b6_0 of each species is dramatic. Blending strongly speeds the rate of relaxation of the high T_g component (PVE), while more modestly slowing the relaxation of the low T_g component (PIP). The dynamics of each species have different temperature dependencies in the blend, which leads to the failure of the superposition principle. Furthermore, both the difference between the friction coefficients of the two species and the difference in their temperature dependencies is greater in blends rich in the high T_g material (PVE).", "date": "1994-07", "date_type": "published", "publication": "Rheologica Acta", "volume": "33", "number": "4", "publisher": "Springer", "pagerange": "322-336", "id_number": "CaltechAUTHORS:20160901-075646346", "issn": "0035-4511", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160901-075646346", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1007/BF00366959", "resource_type": "article", "pub_year": "1994", "author_list": "Arendt, B. H.; Kannan, R. M.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/gcf05-89c27", "eprint_id": 86681, "eprint_status": "archive", "datestamp": "2023-08-20 03:59:14", "lastmod": "2023-10-18 19:52:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kannan-R-M", "name": { "family": "Kannan", "given": "Rangaramanujam M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Evolution of Microstructure and Viscoelasticity during Flow Alignment of a Lamellar Diblock Copolymer", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1994 American Chemical Society. \n\nReceived July 26, 1993; Revised Manuscript Received November 30, 1993. \n\nThis research was carried out with the support of the NSF-PYI program (J.A.K.), with matching funds provided by AT&T. Acknowledgment is also made to the donors of the Petroleum Research Fund, administered by the American Chemical Society, for partial support of this research. We thank Frank Bates for providing PEP-PEE-2. We are grateful to Frank Bates, Ron Larson, and Scott Milner for enlightening discussions.", "abstract": "The effects of flow alignment on the relaxation dynamics of a lamellar diblock copolymer melt and the dynamics of flow alignment itself are investigated using simultaneous measurements of shear stress and birefringence in both the flow plane and the sample plane. The primary advantage of this rheo-optical approach in the context of flow alignment is that it provides quantitative measurements of the evolution of\nthe macroscopic mechanical properties and the state of the microstructure in real time, in situ as alignment occurs. Further, it provides information on the molecular and microstructural dynamics that give rise to flow alignment. An entangled, nearly symmetric poly(ethylene-propylene)-poly(ethylethylene) of 50 kg/mol (PEP-PEE-2) is studied during flow alignment under two different conditions, one that enhances alignment of the lamellae parallel to the sample plane and another that induces alignment perpendicular to the sample plane (lamellar normal along the vorticity axis). The results suggest that the flow process leading to parallel alignment in PEP-PEE-2 is associated with inhomogeneous deformation such that the orientation of domains in the material undergoes irreversible \"rocking\", while the process that produces perpendicular alignment occurs under conditions in which the deformation is nearly homogeneous throughout the material.", "date": "1994-02-28", "date_type": "published", "publication": "Macromolecules", "volume": "27", "number": "5", "publisher": "American Chemical Society", "pagerange": "1177-1186", "id_number": "CaltechAUTHORS:20180529-145208002", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180529-145208002", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "AT&T" }, { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1021/ma00083a016", "resource_type": "article", "pub_year": "1994", "author_list": "Kannan, Rangaramanujam M. and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/95vzm-37c69", "eprint_id": 86680, "eprint_status": "archive", "datestamp": "2023-08-20 03:57:26", "lastmod": "2023-10-18 19:52:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chung-G-C", "name": { "family": "Chung", "given": "G.-C." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "S. D." } } ] }, "title": "Component Dynamics Miscible Polymer Blends: A Two-Dimensional Deuteron NMR Investigation", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1994 American Chemical Society. \n\nReceived August 9, 1993; Revised Manuscript Received November 22, 1993. \n\nWe gratefully acknowledge the support of the National Science Foundation Presidential Young Investigator Award (J.A.K.), Chevron, and the Caltech Consortium in Chemistry and Chemical Engineering: E. I. du Pont de Nemours and Co., Inc., and Eastman Kodak Co.", "abstract": "The dynamics of individual components in 1,4-polyisoprene/poly(vinylethylene) miscible blends are studied using two-dimensional deuteron exchange NMR. The rate of the backbone reorientation process near the glass transition is quantitatively determined for each species in a miscible blend as a function of temperature. We demonstrate that the broad glass transition arises both from a wide distribution of segmental motional rates for each species and from intrinsic differences in the motional rate between the two species. In addition, the temperature dependence of their motional rates in the blend DSC glass transition region suggests that the two components undergo distinct effective glass transitions, which is consistent with previously observed thermorheologically complex behavior. The origins of dynamic heterogeneity are examined further by comparing the experimental results with a simple model calculation that takes into account the effect of composition variations in an ideal miscible blend. This comparison suggests that the observed dynamic heterogeneities can be explained only by including two distinct contributions: local composition variations in the blend and intrinsic differences in chain mobilities.", "date": "1994-02-14", "date_type": "published", "publication": "Macromolecules", "volume": "27", "number": "4", "publisher": "American Chemical Society", "pagerange": "964-973", "id_number": "CaltechAUTHORS:20180529-144753548", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180529-144753548", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Chevron Corporation" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" } ] }, "doi": "10.1021/ma00082a013", "resource_type": "article", "pub_year": "1994", "author_list": "Chung, G.-C.; Kornfield, J. A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7qnta-28n05", "eprint_id": 86169, "eprint_status": "archive", "datestamp": "2023-08-20 02:36:25", "lastmod": "2023-10-18 19:19:03", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kannan-R-M", "name": { "family": "Kannan", "given": "Rangaramanujam M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Schwenk-N", "name": { "family": "Schwenk", "given": "Norbert" } }, { "id": "Boeffel-C", "name": { "family": "Boeffel", "given": "Christine" } } ] }, "title": "Rheology of side-group liquid-crystalline polymers: effect of isotropic-nematic transition and evidence of flow alignment", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1993 American Chemical Society. \n\nReceived November 16, 1992; Revised Manuscript Received January 7, 1993. \n\nWe gratefully acknowledge the support of the National Science Foundation Presidential Young Investigator Award (J.A.K.), the Gates Grubstake Fund, and the NATO-Travel Grant Program (CRG 901037). We thank Ute Pawelzik at the Max-Planck-Institut f\u00fcr Polymerforschung for synthesizing the polymers for this research.", "abstract": "The dynamics of a nematic sidegroup liquid-crystalline polymer (SG-LCP) melt are investigated using transient stress and birefringence measurements. This SG-LCP shows a pronounced drop in the dynamic moduli at sufficiently low frequency upon passing through the transition from the isotropic to the nematic state. In contrast to previous studies, this suggests that liquid-crystalline order does affect the relaxation dynamics of SG-LCP melts. In the isotropic phase we simultaneously measure dynamic birefringence and stress to determine the stress-optic ratio (SOR). Results in the isotropic state near T_(ni) show the anomalously large SOR characteristic of pretransitional effects in liquid-crystalline systems in general. In the nematic state, we find that prolonged, large-amplitude oscillatory shear dramatically reduces the turbidity and increases the birefringence of the sample, suggesting that shearing induces a preferred alignment in this SG-LCP melt. This is accompanied by a decrease in the effective dynamic moduli of the nematic.", "date": "1993-04-12", "date_type": "published", "publication": "Macromolecules", "volume": "26", "number": "8", "publisher": "American Chemical Society", "pagerange": "2050-2056", "id_number": "CaltechAUTHORS:20180501-151529412", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180501-151529412", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Caltech Gates Grubstake Fund" }, { "agency": "North Atlantic Treaty Organization (NATO)", "grant_number": "CRG 901037" } ] }, "doi": "10.1021/ma00060a038", "resource_type": "article", "pub_year": "1993", "author_list": "Kannan, Rangaramanujam M.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/y9jez-38f40", "eprint_id": 103257, "eprint_status": "archive", "datestamp": "2023-08-22 09:04:00", "lastmod": "2023-10-20 15:50:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kannan-R-M", "name": { "family": "Kannan", "given": "R. M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "The third-normal stress difference in entangled melts: Quantitative stress-optical measurements in oscillatory shear", "ispublished": "pub", "full_text_status": "public", "keywords": "third normal stress difference; oscillatory shear; flow birefringence; entangled melts; polyisoprene; poly(ethylene-propylene)", "note": "\u00a9 1992 Springer Verlag. \n\nReceived 25 July 1992; Revised 02 September 1992.", "abstract": "Stress-optical measurements are used to quantitatively determine the third-normal stress difference (N\u2083 = N\u2081 + N\u2082) in three entangled polymer melts during small amplitude (<15%) oscillatory shear over a wide dynamic range. The results are presented in terms of the three material functions that describe N\u2083 in oscillatory shear: the real and imaginary parts of its complex amplitude \u03c8*\u2083 = \u03c8\u2032\u2083- i\u03c8\u2033\u2083, and its displacement \u03c8^d\u2083. The results confirm that these functions are related to the dynamic modulus by \u03c9\u00b2\u03c8*\u00b2 (\u03c9)=(1-\u03b2)[G *(\u03c9))\u22121/2 G *(2\u03c9)] and \u03c9\u00b2\u03c8d\u00b2 (\u03c9)=(1- \u03b2)G\u2032(\u03c9) as predicted by many constitutive equations, where \u03b2 = \u2212N\u2082/N\u2081. The value of (1-\u03b2) is found to be 0.69\u00b10.07 for poly(ethylene-propylene) and 0.76\u00b10.07 for polyisoprene. This corresponds to \u2212N\u2082/N\u2081 = 0.31 and 0.24\u00b10.07, close to the prediction of the reptation model when the independent alignment approximation is used, i.e., \u2212N\u2082/N\u2081 = 2/7 \u2212 0.28.", "date": "1992-11", "date_type": "published", "publication": "Rheologica Acta", "volume": "31", "number": "6", "publisher": "Springer", "pagerange": "535-544", "id_number": "CaltechAUTHORS:20200518-073137020", "issn": "0035-4511", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200518-073137020", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1007/bf00367008", "resource_type": "article", "pub_year": "1992", "author_list": "Kannan, R. M. and Kornfield, J. A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/6av9z-13q73", "eprint_id": 88067, "eprint_status": "archive", "datestamp": "2023-08-20 01:37:37", "lastmod": "2023-10-18 21:41:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Chung-Geunchang", "name": { "family": "Chung", "given": "Geun Chang" } }, { "id": "Smith-S-D", "name": { "family": "Smith", "given": "Steven D." } } ] }, "title": "Reconsideration of deuterium NMR observations of orientational coupling in polymer networks in light of motional heterogeneity in styrene-d_8-styrene block copolymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1992 American Chemical Society. \n\nReceived December 16, 1991. Revised Manuscript Received May 5, 1992. \n\nThis work was supported by the NSF Presidential Young Investigator Program (J.A.K.).", "abstract": "To test the plausibility of substantial dynamic heterogeneity between dangling chains and true network chains, we characterize the difference in mobility between the ends and the center of an entangled linear polymer using styrene-d_8-styrene block copolymers.", "date": "1992-08-17", "date_type": "published", "publication": "Macromolecules", "volume": "25", "number": "17", "publisher": "American Chemical Society", "pagerange": "4442-4444", "id_number": "CaltechAUTHORS:20180720-130630439", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180720-130630439", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/ma00043a031", "resource_type": "article", "pub_year": "1992", "author_list": "Kornfield, Julia A.; Chung, Geun Chang; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/c90ny-yrc47", "eprint_id": 87987, "eprint_status": "archive", "datestamp": "2023-08-20 01:19:34", "lastmod": "2024-01-14 20:28:28", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Infrared polarimetry: gaining a molecular view of polymer viscoelasticity", "ispublished": "unpub", "full_text_status": "public", "note": "\u00a9 1992 Society of Photo-Optical Instrumentation Engineers (SPIE).\n\nPublished - 18.pdf
", "abstract": "Recent exciting advances have been made using infrared (IR) diode lasers to obtain sensitive and rapid measurements of molecular-level dynamics that control polymer material properties. Infrared diodes provide a bright, nearly monochromatic, polarized source that is excellent for use in polarimetry. Optical polarimetry is the measurement of the state of polarization of light. It is a powerful technique for studying molecular and microstructural anisotropy in a sample by measuring how the sample alters the polarization of a transmitted beam. In polymers, it is precisely such molecular anisotropy that underlies their viscoelastic properties. As theories are developed to predict the relaxation dynamics of individual parts of a polymer molecule, and of different species in polymer blends, there is increasing interest in experimental methods to distinguish these dynamics. Infrared polarimetry is extremely valuable in this regard, not only because of the direct relationship between the IR dichroism and molecular orientation, but also because it is amenable to labeling. The present paper reviews the basis of this technique and its application to study the effects of polydispersity on melt rheology, and the relaxation dynamics at different positions along a polymer chain. It concludes with an overview of research in progress and future problems to be tackled.", "date": "1992-05-14", "date_type": "published", "publisher": "Society of Photo-optical Instrumentation Engineers (SPIE)", "place_of_pub": "Bellingham, WA", "pagerange": "18-26", "id_number": "CaltechAUTHORS:20180718-164613247", "isbn": "0819407828", "book_title": "Applied Spectroscopy in Materials Science II", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180718-164613247", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Golden-W-G", "name": { "family": "Golden", "given": "William G." } } ] }, "doi": "10.1117/12.59291", "primary_object": { "basename": "18.pdf", "url": "https://authors.library.caltech.edu/records/c90ny-yrc47/files/18.pdf" }, "resource_type": "book_section", "pub_year": "1992", "author_list": "Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/cbj2k-bpt23", "eprint_id": 79152, "eprint_status": "archive", "datestamp": "2023-08-20 00:51:33", "lastmod": "2023-10-26 14:38:09", "type": "book_section", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chung-Geunchang", "name": { "family": "Chung", "given": "Geunchang" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Two-Dimensional Deuteron Exchange NMR Studies of the Dynamics of Individual Species in Miscible Blends", "ispublished": "unpub", "full_text_status": "public", "note": "\u00a9 1992 Elsevier B.V.", "abstract": "[no abstract]", "date": "1992", "date_type": "published", "publisher": "Elsevier", "place_of_pub": "Amsterdam", "pagerange": "333-335", "id_number": "CaltechAUTHORS:20170718-104237153", "isbn": "978-0-444-89007-8", "book_title": "Theoretical and Applied Rheology", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170718-104237153", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "contributors": { "items": [ { "id": "Moldenaers-P", "name": { "family": "Moldenaers", "given": "P." } }, { "id": "Keunings-R", "name": { "family": "Keunings", "given": "R." } } ] }, "doi": "10.1016/B978-0-444-89007-8.50136-2", "resource_type": "book_section", "pub_year": "1992", "author_list": "Chung, Geunchang and Kornfield, Julia A." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/tkxj8-8vh74", "eprint_id": 88069, "eprint_status": "archive", "datestamp": "2023-08-20 00:25:32", "lastmod": "2023-10-18 21:41:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Fuller-G-G", "name": { "family": "Fuller", "given": "Gerald G." }, "orcid": "0000-0002-2924-053X" }, { "id": "Pearson-D-S", "name": { "family": "Pearson", "given": "Dale S." } } ] }, "title": "Third normal stress difference and component relaxation spectra for bidisperse melts under oscillatory shear", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1991 American Chemical Society. \n\nReceived January 24, 1991; Revised Manuscript Received May 8, 1991. \n\nWe are grateful for support for this research from the National Science Foundation through the Presidential Young Investigator (G. Fuller) and Graduate Fellowship (J. Kornfield) programs and from the Exxon Foundation and the Center for Materials Research at Stanford University. We thank Lewis Fetters for synthesizing the polymers employed in this study. We would like to thank Ron Larson for reading the manuscript and for his helpful comments and suggestions.", "abstract": "A recently developed rheooptical technique that simultaneously measures infrared dichroism and birefringence is used to study bidisperse, linear polymer melts in an oscillatory shear. The method was used to individually measure the contribution of the high and low molecular weight components to the third normal stress difference. This was accomplished by measuring the infrared dichroism due to deuterium-labeled polymers. Binary blends are prepared from nearly monodisperse pairs of hydrogenated and deuteriated polyisoprenes of molecular weights 53 000 and 370 000 with volume fractions of long polymer, \u03a6_L, of 0.10, 0.20, 0.30, 0.50, and 0.75. The long-chain relaxation in the blends shows the appearance of a peak for compositions with \u03a6_L \u2264 0.50 at approximately the same frequency as a similar peak in the pure short polymer. The response of the short-chain relaxation in the blends shows the appearance of a low-frequency shoulder that becomes surprisingly large as the volume fraction of long chains increases. The results are used to test a modified reptation model that includes constraint release and a short-range orientational coupling between chain segments.", "date": "1991-09-16", "date_type": "published", "publication": "Macromolecules", "volume": "24", "number": "19", "publisher": "American Chemical Society", "pagerange": "5429-5441", "id_number": "CaltechAUTHORS:20180720-132716832", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180720-132716832", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Exxon Education Foundation" }, { "agency": "Stanford University" } ] }, "doi": "10.1021/ma00019a034", "resource_type": "article", "pub_year": "1991", "author_list": "Kornfield, Julia A.; Fuller, Gerald G.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/cy9ya-g9p70", "eprint_id": 88071, "eprint_status": "archive", "datestamp": "2023-08-20 00:20:41", "lastmod": "2023-10-18 21:43:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Spiess-H-W", "name": { "family": "Spiess", "given": "H. W." } }, { "id": "Nefzger-H", "name": { "family": "Nefzger", "given": "H." } }, { "id": "Hayen-H", "name": { "family": "Hayen", "given": "H." } }, { "id": "Eisenbach-C-D", "name": { "family": "Eisenbach", "given": "C. D." } } ] }, "title": "Deuteron NMR measurements of order and mobility in the hard segments of a model polyurethane", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1991 American Chemical Society. \n\nReceived December 18, 1990; Revised Manuscript Received March 25, 1991. \n\nSupport for this research was provided by the U.S. National Science Foundation through the NATO Postdoctoral Fellowship Program (supporting J. Kornfield) and by the Bundesminister f\u00fcr Forschung und Technologie (supporting H. Hayen, Grant No. 03EiBay 5). We appreciate the many fruitful discussions of this research with D. Meltzer, T. Pakula, and G. Planer.", "abstract": "Pulsed deuteron NMR results are reported for a series of segmented model polyurethanes with monodisperse hard segments containing specifically labeled sites. The hard segments consist of five piperazine rings ( 1-5) separated by carbonyloxytetramethyleneoxycarbonyl spacers; three labeled derivatives are used, with piperazine-d_8 at the 1,5-, 2,4-, and 3-rings. The soft segments are polydisperse poly(tetramethylene oxide) (M_n \u2248 2000). To facilitate interpretation of the polyurethane spectra, measurements are also made on model compounds of the hard segment oligomer, and a model polymer consisting of soft segments chain extended by individual piperazine-d_8 rings. The results indicate that 85% of the hard segments exist in the hard phase, with low mobility at temperatures below 410 K (\u2248T_m - 10 K). The rest of the hard segments appear to be dispersed in the soft phase, with high mobility at temperatures above 260 K (\u2248T_g + 60 K). Molecular mobility is much greater at the exterior than the center of hard segments in the hard phase at temperatures between 300 and 410 K. Comparison of changes in molecular mobility and in the storage modulus with temperature (T) shows that (1) as T increases from 200 to 280 K, increase in mobility of the soft phase due to the glass-to-rubber transition and crystallite melting correlates with the 100-fold decrease in modulus in this range, (2) as T increases to 400 K, increase in mobility at the exterior of the hard phase correlates with the gradual decrease in modulus, and (3) at T \u2248 410 K, onset of high mobility at the center of hard segments in the hard phase correlates with the loss of mechanical integrity.", "date": "1991-08-19", "date_type": "published", "publication": "Macromolecules", "volume": "24", "number": "17", "publisher": "American Chemical Society", "pagerange": "4787-4795", "id_number": "CaltechAUTHORS:20180720-133239634", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180720-133239634", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "North Atlantic Treaty Organization (NATO)" }, { "agency": "Bundesminister f\u00fcr Forschung und Technologie", "grant_number": "03EiBay 5" } ] }, "doi": "10.1021/ma00017a009", "resource_type": "article", "pub_year": "1991", "author_list": "Kornfield, J. A.; Spiess, H. W.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/41mp0-8za15", "eprint_id": 88074, "eprint_status": "archive", "datestamp": "2023-08-19 23:44:25", "lastmod": "2023-10-18 21:43:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ylitalo-C-M", "name": { "family": "Ylitalo", "given": "Caroline M." } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Fuller-G-G", "name": { "family": "Fuller", "given": "Gerald G." }, "orcid": "0000-0002-2924-053X" }, { "id": "Pearson-D-S", "name": { "family": "Pearson", "given": "Dale S." } } ] }, "title": "Molecular weight dependence of component dynamics in bidisperse melt rheology", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1991 American Chemical Society. \n\nReceived April 19, 1990; Revised Manuscript Received July 30, 1990. \n\nWe are grateful to the National Science Foundation for support through the Presidential Young Investigator program for G. Fuller. This work was also supported by the Exxon Foundation and the Center for Materials Research at Stanford University. We thank Lewis Fetters for synthesizing the polymers used in this study.", "abstract": "Simultaneous measurement of infrared dichroism and birefringence is used to study component relaxation in bimodal molecular weight distribution melts. Nearly monodisperse poly(ethylenepropylene) samples of molecular weights 53K, 125K, and 370K, all above the critical molecular weight for entanglement, were used. Results for the step-strain relaxation of each component and of the total sample are presented and discussed for binary blends of 10, 20, 30, 50, and 75% by volume of the higher molecular weight species for three seta of blends: 53K/125K, 53K/370K, and 125K/370K. For each sample, the relaxation dynamics of the blend and of each component depend upon the two polymer relaxation times and the blend composition. Effects of intermolecular orientational coupling interactions were observed, and a coupling strength of 0.45 was measured. The results of these experiments are compared to a reptation-based constraint release model, and a qualitative agreement is found.", "date": "1991-02-04", "date_type": "published", "publication": "Macromolecules", "volume": "24", "number": "3", "publisher": "American Chemical Society", "pagerange": "749-758", "id_number": "CaltechAUTHORS:20180720-134054459", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180720-134054459", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Exxon Educational Foundation" }, { "agency": "Stanford University" } ] }, "doi": "10.1021/ma00003a019", "resource_type": "article", "pub_year": "1991", "author_list": "Ylitalo, Caroline M.; Kornfield, Julia A.; et el." }, { "id": "https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8gf7q-b4m86", "eprint_id": 103256, "eprint_status": "archive", "datestamp": "2023-08-22 07:10:28", "lastmod": "2023-10-20 15:50:36", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "J. A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Fuller-G-G", "name": { "family": "Fuller", "given": "G. G." }, "orcid": "0000-0002-2924-053X" }, { "id": "Pearson-D-S", "name": { "family": "Pearson", "given": "D. S." } } ] }, "title": "Stress optical measurement of the third normal stress difference in polymer melts under oscillatory shear", "ispublished": "pub", "full_text_status": "public", "keywords": "Polyisoprenes; third normal stress difference; oscillatory flow; shear stress; dynamic moduli", "note": "\u00a9 1991 Springer Verlag. \n\nReceived 21 June 1989; Revised 22 February 1990.", "abstract": "Results are reported for the dynamic moduli, G\u2032 and G\u2033, measured mechanically, and the dynamic third normal stress difference, measured optically, of a series bidisperse linear polymer melts under oscillatory shear. Nearly monodisperse hydrogenated polyisoprenes of molecular weights 53000 and 370000 were used to prepare blends with a volume fraction of long polymer, \u03a6_L, of 0.10, 0.20, 0.30, 0.50, and 0.75. The results demonstrate the applicability of birefringence measurements to solve the longstanding problem of measuring the third normal stress difference in oscillatory flow. The relationship between the third normal stress difference and the shear stress observed for these entangled polymer melts is in agreement with a widely predicted constitutive relationship: the relationship between the first normal stress difference and the shear stress is that of a simple fluid, and the second normal stress difference is proportional to the first. These results demonstrate the potential use of 1,3-birefringence to measure the third normal stress difference in oscillatory flow. Further, the general constitutive equation supported by the present results may be used to determine the dynamic moduli from the measured third normal stress difference in small amplitude oscillatory shear. Directions for future research, including the use of birefringence measurements to determine N\u2082/N\u2081 in oscillatory shear, are described.", "date": "1990-03", "date_type": "published", "publication": "Rheologica Acta", "volume": "29", "number": "2", "publisher": "Springer", "pagerange": "105-116", "id_number": "CaltechAUTHORS:20200518-072632377", "issn": "0035-4511", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200518-072632377", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1007/bf01332377", "resource_type": "article", "pub_year": "1990", "author_list": "Kornfield, J. A.; Fuller, G. G.; et el." } ]