DOCSLIB.ORG

PDF (Complete Thesis)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
PDF (Complete Thesis) Intramolecular Conflict: Conformation and Self-Assembly of Architecturally Complex Macromolecules in Solution Thesis by Paul Pirogovsky In Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2014 (Defended Nov 1st, 2013) ii 2014 Paul Pirogovsky All Rights Reserved iii ACKNOWLEDGEMENTS I am grateful to all of the people who have contributed to the completion of this thesis either by furthering the work detailed within or by supporting me during the process. First of all I would like to thank my advisor Julie Kornfield for taking me under her wing and keeping me inspired during all of the years that it took to complete this work. Her enthusiasm and insight helped me to look past the failures and to see opportunities and always helped me to see the beautiful science hidden behind all of the dirty glassware. I would also like to thank Zhen-Gang Wang for being my first mentor at Caltech and for continuing to support me even when I was struggling and unsure of what to do next. I am grateful to Milo Koretsky and Skip Rochefort who let me muddle about in their labs as an undergraduate and thereby gave me my first taste of research. I appreciate the time and energy put in by the members of my committee (Professors Mark Davis, David Tirrell and Zhen-Gang Wang) in reviewing my thesis. Throughout my time at Caltech I have always been amazed at just how helpful people can be. Mike Roy made a lot of parts for my half-baked designs and more importantly was always happy to teach me how to do it myself next time. Rick Gerhardt is amazing with glassware and never made me feel too badly about having broken a Schlenk line. Everyone on the second floor of Spalding has been nice and willing to go out of their way to help. Suresh Gupta kept the computers crunching numbers and securely storing data and was instrumental in setting up the Kornfield lab cluster. Marcy Fowler and later Andrea Arias kept track of the craziness that is the Kornfield lab calendar and made travel a breeze. Kathy Bubash and Karen Baumgartner were always there to discuss the meaning of life and also make sure that forms made it to the right place and things actually got done. The best part of a lab is always the people and it was a pleasure to work with the awesome folks in the Kornfield lab. I enjoyed the many interesting and in-depth conversations that I had with Matthew Mattson and Loddie Foose, both kind and thoughtful people even if their political views fall on opposite ends of the spectrum. Nothing brings people closer than sleepless nights spent together surrounded by giant machinery running neutron and x-ray iv experiments. I will always happily remember the scattering trips with my brothers and sisters in arms: Zuli Kurji, Rohan Hule, Artemis Ailianou, Joey Kim and Boyu Li. It’s been fun hanging out and complaining about life with Amy Fu, with whom I feel comfortable talking about pretty much everything. Jeremy Wei was always there to help out with anything in the lab, kept us all safe, and taught me the little that I know about synthetic procedures. Brad Olsen is a nice guy, a fantastic role model, and the most talented person with whom I have had the privilege of working. I am really grateful to have spent my grad school years surrounded by great people, as it really made the time fly. Many of the experiments described in this thesis were conducted at various national laboratory facilities. I would like to acknowledge the Department of Energy (DOE) and Department of Commerce for supporting the facilities of Argonne National Laboratory (ANL), Lawrence Berkeley National Laboratory (LBNL), the National Institute of Standards and Technology (NIST), Los Alamos National Laboratory (LANL) and Oak Ridge National Laboratory (ORNL). I am grateful for the opportunity to learn about experimental techniques and data analysis provided by the DOE in the form of the National School of X-ray and Neutron Scattering. It was awesome to get a chance to learn from the leading experts in the field. Some of those same experts later helped me with the experiments. They designed, built and supported the scattering instruments at the national laboratory facility and help even the most demanding and difficult of users. I would like to thank Boualem Hammouda, John Barker, Lionel Porcar, Cedric Gagnon, Jeff Kryzwon, Kim Tomasi, Rex Hjelm, Monika Hartl, Ken Littrell, Lilin He, Kathy Bailey, John Ankner, Jim Browning and Candice Halbert for all of their help in making the scattering happen. I am grateful to my family for being supportive and for always being there to help or just to lend an ear. Michael and Karen accepted me into their family and made me feel loved whenever we saw each other. Megan and Dane are the siblings that I never had. My parents Peter and Nina inspired me to go into science and provided the financial, intellectual and emotional support that I needed to get to the end of this journey. My grandfather Oleg and grandmother Sylvia were always there to share tales of research in a very different environment and were happy to listen to me talk about my work while feeding me as much v as I could possibly eat. Without family, life is empty, and thanks to you mine has always been full. Finally I want to thank the wonderful lady who came with me to Southern California and agreed to be my wife. Mallory is wonderful, smart, sweet, and snarky and has always made me smile, even when absolutely nothing was working. We also got to share the PhD experience, and she led the way, becoming the first Dr. Pirogovsky of our generation. It’s been grand, so long, and thanks for all the fish. vi ABSTRACT The solution behavior of linear polymer chains is well understood, having been the subject of intense study throughout the previous century. As plastics have become ubiquitous in everyday life, polymer science has grown into a major field of study. The conformation of a polymer in solution depends on the molecular architecture and its interactions with the surroundings. Developments in synthetic techniques have led to the creation of precision-tailored polymeric materials with varied topologies and functionalities. In order to design materials with the desired properties, it is imperative to understand the relationships between polymer architecture and their conformation and behavior. To meet that need, this thesis investigates the conformation and self-assembly of three architecturally complex macromolecular systems with rich and varied behaviors driven by the resolution of intramolecular conflicts. First we describe the development of a robust and facile synthetic approach to reproducible bottlebrush polymers (Chapter 2). The method was used to produce homologous series of bottlebrush polymers with polynorbornene backbones, which revealed the effect of side-chain and backbone length on the overall conformation in both good and theta solvent conditions (Chapter 3). The side-chain conformation was obtained from a series of SANS experiments and determined to be indistinguishable from the behavior of free linear polymer chains. Using deuterium-labeled bottlebrushes, we were able for the first time to directly observe the backbone conformation of a bottlebrush polymer which showed self-avoiding walk behavior. Secondly, a series of SANS experiments was conducted on a homologous series of Side Group Liquid Crystalline Polymers (SGLCPs) in a perdeuterated small molecule liquid crystal (5CB). Monodomain, aligned, dilute samples of SGLCP-b-PS block copolymers were seen to self- assemble into complex micellar structures with mutually orthogonally oriented anisotropies at vii different length scales (Chapter 4). Finally, we present the results from the first scattering experiments on a set of fuel-soluble, associating telechelic polymers. We observed the formation of supramolecular aggregates in dilute (≤0.5wt%) solutions of telechelic polymers and determined that the choice of solvent has a significant effect on the strength of association and the size of the supramolecules (Chapter 5). A method was developed for the direct estimation of supramolecular aggregation number from SANS data. The insight into structure- property relationships obtained from this work will enable the more targeted development of these molecular architectures for their respective applications. viii TABLE OF CONTENTS Acknowledgements ........................................................................................................ iii Abstract ........................................................................................................................... vi Table of Contents ......................................................................................................... viii List of Figures .................................................................................................................. x List of Tables ................................................................................................................. xii List of Schemes ............................................................................................................ xiii Chapter 1: Introduction 1.1 Intramolecular Conflict .................................................................................... I-1 1.2 Polymer Chains in Solution ............................................................................. I-3 1.3 Experimental Characterization of Polymers .................................................. I-12 1.4
Load more

Recommended publications
  • Synthesis, Rheology, Neutron Scattering
    Downloaded from orbit.dtu.dk on: May 16, 2018 Entangled Polymer Melts in Extensional Flow: Synthesis, Rheology, Neutron Scattering Dorokhin, Andriy Publication date: 2018 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Dorokhin, A. (2018). Entangled Polymer Melts in Extensional Flow: Synthesis, Rheology, Neutron Scattering. DTU Nanotech. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Entangled Polymer Melts in Extensional Flow: Synthesis, Rheology, Neutron Scattering Andriy Dorokhin PhD Thesis December 2017 Ph.D. Thesis Doctor of Philosophy Entangled Polymer Melts in Extensional Flow: Synthesis, Rheology, Neutron Scattering Andriy Dorokhin Kongens Lyngby 2018 DTU Nanotech Department of Micro- and Nanotechnology Technical University of Denmark Produktionstorvet,
    [Show full text]
  • Form and Structure Factors: Modeling and Interactions Jan Skov Pedersen, Department of Chemistry and Inano Center University of Aarhus Denmark SAXS Lab
    Form and Structure Factors: Modeling and Interactions Jan Skov Pedersen, Department of Chemistry and iNANO Center University of Aarhus Denmark SAXS lab 1 Outline • Model fitting and least-squares methods • Available form factors ex: sphere, ellipsoid, cylinder, spherical subunits… ex: polymer chain • Monte Carlo integration for form factors of complex structures • Monte Carlo simulations for form factors of polymer models • Concentration effects and structure factors Zimm approach Spherical particles Elongated particles (approximations) Polymers 2 Motivation - not to replace shape reconstruction and crystal-structure based modeling – we use the methods extensively - alternative approaches to reduce the number of degrees of freedom in SAS data structural analysis (might make you aware of the limited information content of your data !!!) - provide polymer-theory based modeling of flexible chains - describe and correct for concentration effects 3 Literature Jan Skov Pedersen, Analysis of Small-Angle Scattering Data from Colloids and Polymer Solutions: Modeling and Least-squares Fitting (1997). Adv. Colloid Interface Sci. , 70 , 171-210. Jan Skov Pedersen Monte Carlo Simulation Techniques Applied in the Analysis of Small-Angle Scattering Data from Colloids and Polymer Systems in Neutrons, X-Rays and Light P. Lindner and Th. Zemb (Editors) 2002 Elsevier Science B.V. p. 381 Jan Skov Pedersen Modelling of Small-Angle Scattering Data from Colloids and Polymer Systems in Neutrons, X-Rays and Light P. Lindner and Th. Zemb (Editors) 2002 Elsevier
    [Show full text]
  • Polymers: Structure
    Polymers: Structure W. Pyckhout-Hintzen This document has been published in Manuel Angst, Thomas Brückel, Dieter Richter, Reiner Zorn (Eds.): Scattering Methods for Condensed Matter Research: Towards Novel Applications at Future Sources Lecture Notes of the 43rd IFF Spring School 2012 Schriften des Forschungszentrums Jülich / Reihe Schlüsseltechnologien / Key Tech- nologies, Vol. 33 JCNS, PGI, ICS, IAS Forschungszentrum Jülich GmbH, JCNS, PGI, ICS, IAS, 2012 ISBN: 978-3-89336-759-7 All rights reserved. E 2 Polymers: Structure W. Pyckhout-Hintzen Jülich Centre for Neutron Science 1 & Institute for Complex Systems 1 Forschungszentrum Jülich GmbH Contents 1 Introduction............................................................................................... 2 2 Polymer Chain Models and Architecture............................................... 3 3 Scattering: intra- and inter-chain contributions.................................... 7 4 Blend of linear Polymers .......................................................................... 9 5 Tri-block copolymers..............................................................................13 6 Branched Chains .....................................................................................15 7 Summary..................................................................................................18 Appendix ............................................................................................................19 References ..........................................................................................................20
    [Show full text]
  • Form and Structure Factors: Modeling and Interactions Jan Skov Pedersen, Inano Center and Department of Chemistry SAXS Lab University of Aarhus Denmark
    Form and Structure Factors: Modeling and Interactions Jan Skov Pedersen, iNANO Center and Department of Chemistry SAXS lab University of Aarhus Denmark 1 New SAXS instrument in ultimo Nov 2014: Funding from: Research Council for Independent Research: Natural Science The Carlsberg Foundation The Novonordisk Foundation 2 Liquid metal jet X-ray sourcec Gallium Kα X-rays (λ = 1.34 Å) 3 x 109 photons/sec!!! 3 Special Optics Scatterless slits + optimized geometry: High Performance 2D 10 3 x 10 ph/sec!!! Detector Stopped-flow for rapid mixing Sample robot 4 Outline • Model fitting and least-squares methods • Available form factors ex: sphere, ellipsoid, cylinder, spherical subunits… ex: polymer chain • Monte Carlo integration for form factors of complex structures • Monte Carlo simulations for form factors of polymer models • Concentration effects and structure factors Zimm approach Spherical particles Elongated particles (approximations) Polymers 5 Motivation for ‘modelling’ - not to replace shape reconstruction and crystal-structure based modeling – we use the methods extensively - alternative approaches to reduce the number of degrees of freedom in SAS data structural analysis (might make you aware of the limited information content of your data !!!) - provide polymer-theory based modeling of flexible chains - describe and correct for concentration effects 6 Literature Jan Skov Pedersen, Analysis of Small-Angle Scattering Data from Colloids and Polymer Solutions: Modeling and Least-squares Fitting (1997). Adv. Colloid Interface Sci., 70, 171-210. Jan Skov Pedersen Monte Carlo Simulation Techniques Applied in the Analysis of Small-Angle Scattering Data from Colloids and Polymer Systems in Neutrons, X-Rays and Light P. Lindner and Th.
    [Show full text]
  • Form and Structure Factors: Modeling and Interactions Jan Skov Pedersen, Department of Chemistry and Inano Center University of Aarhus Denmark SAXS Lab
    Form and Structure Factors: Modeling and Interactions Jan Skov Pedersen, Department of Chemistry and iNANO Center University of Aarhus Denmark SAXS lab 1 Outline • Model fitting and least-squares methods • Available form factors ex: sphere, ellipsoid, cylinder, spherical subunits… ex: polymer chain • Monte Carlo integration for form factors of complex structures • Monte Carlo simulations for form factors of polymer models • Concentration effects and structure factors Zimm approach Spherical particles Elongated particles (approximations) Polymers 2 Motivation for ‘modelling’ - not to replace shape reconstruction and crystal-structure based modeling – we use the methods extensively - alternative approaches to reduce the number of degrees of freedom in SAS data structural analysis (might make you aware of the limited information content of your data !!!) - provide polymer-theory based modeling of flexible chains - describe and correct for concentration effects 3 Literature Jan Skov Pedersen, Analysis of Small-Angle Scattering Data from Colloids and Polymer Solutions: Modeling and Least-squares Fitting (1997). Adv. Colloid Interface Sci., 70, 171-210. Jan Skov Pedersen Monte Carlo Simulation Techniques Applied in the Analysis of Small-Angle Scattering Data from Colloids and Polymer Systems in Neutrons, X-Rays and Light P. Lindner and Th. Zemb (Editors) 2002 Elsevier Science B.V. p. 381 Jan Skov Pedersen Modelling of Small-Angle Scattering Data from Colloids and Polymer Systems in Neutrons, X-Rays and Light P. Lindner and Th. Zemb (Editors)
    [Show full text]
  • Multiple-Length-Scale Small-Angle X-Ray Scattering Analysis On
    conference papers Journal of Applied Multiple-length-scale small-angle X-ray scattering Crystallography analysis on maghemite nanocomposites ISSN 0021-8898 Angel Millan,a* Ainhoa Urtizberea,a Nuno Joao de Oliveira Silva,b Peter Boesecke,c Received 16 August 2006 Eva Natividad,a Fernando Palacio,a Etienne Snoeck,d Leonardo Soriano,e Alejandro Accepted 26 February 2007 Gutie´rreze and Carlos Quiro´sf aInstituto de Ciencia de Materiales de Arago´n, Spain, bDepartamento de Fı´sica, Universidade de Aveiro, Portugal, cEuropean Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex, France, dCEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse Cedex, France, eDepartamento de Fı´sica Aplicada, Universidad Auto´noma de Madrid, Madrid, E-28049, Spain, and fDepartamento de Fı´sica, Universidad de Oviedo, Avda. Calvo Sotelo s/n, 33007 Oviedo, Spain. Correspondence e-mail: [email protected] Small-angle X-ray scattering (SAXS) analysis has been performed on maghemite–poly(4-vinylpyridine) nanocomposites prepared by in situ precipita- tion from iron–polymer coordination compounds. According to electron microscopy observations, the nanocomposites contain isolated spherical particles with a narrow size distribution, uniformly distributed throughout the polymer matrix. The scattering intensity of nanocomposites has relevant contributions from both the polymer and the nanocomposites, showing features characteristic of multiscale structured systems, namely two power laws and a Guinier regime. The data have been analysed in terms of Beaucage’s unified approach and it is found that the maghemite particle size increases with the iron/ polymer weight ratio used in the preparation of the nanocomposites. SAXS curves also feature a bump that was analysed as arising from a second particle population or from interactions.
    [Show full text]
  • Nanostructures Investigated by Small Angle Neutron Scat- Tering
    Nanostructures Investigated by Small Angle Neutron Scat- tering H. Frielinghaus This document has been published in Thomas Brückel, Gernot Heger, Dieter Richter, Georg Roth and Reiner Zorn (Eds.): Lectures of the JCNS Laboratory Course held at Forschungszentrum Jülich and the research reactor FRM II of TU Munich In cooperation with RWTH Aachen and University of Münster Schriften des Forschungszentrums Jülich / Reihe Schlüsseltechnologien / Key Tech- nologies, Vol. 39 JCNS, RWTH Aachen, University of Münster Forschungszentrum Jülich GmbH, 52425 Jülich, Germany, 2012 ISBN: 978-3-89336-789-4 All rights reserved. 5 Nanostructures Investigated by Small Angle Neutron Scattering H. Frielinghaus Julich¨ Centre for Neutron Science Forschungszentrum Julich¨ GmbH Contents 5.1 Introduction 2 5.2 Survey about the SANS technique 3 5.2.1 The scattering vector Q ............................ 5 5.2.2 The Fourier transformation in the Born approximation ............ 5 5.2.3 Remarksonfocusinginstruments . ..... 8 5.2.4 Measurement of the macroscopic cross section . ......... 10 5.2.5 Incoherentbackground. ... 10 5.2.6 Resolution ................................... 11 5.3 The theory of the macroscopic cross section 13 5.3.1 Spherical colloidal particles . ....... 17 5.3.2 Contrastvariation. ... 20 5.3.3 Scatteringofapolymer. ... 22 5.3.4 Thestructurefactor. ... 26 5.3.5 Microemulsions ................................ 30 5.4 Small angle x-ray scattering 32 5.4.1 Contrast variation using anomalous small angle x-ray scattering . 33 5.4.2 ComparisonofSANSandSAXS . 34 5.5 Summary 37 Appendices 38 References 42 Exercises 43 Lecture Notes of the JCNS Laboratory Course Neutron Scattering (Forschungszentrum Julich,¨ 2012, all rights reserved) 5.2 H. Frielinghaus 5.1 Introduction Small angle neutron scattering aims at length scales ranging from nanometers to microme- ters [1, 2].
    [Show full text]
  • Deformation Studies of Polymers and Polymer/Clay
    DEFORMATION STUDIES OF POLYMERS AND POLYMER/CLAY NANOCOMPOSITES A Dissertation Presented to The Academic Faculty by Bilge Gurun In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Polymer, Textile and Fiber Engineering Georgia Institute of Technology December 2010 COPYRIGHT 2010 BY BILGE GURUN DEFORMATION STUDIES OF POLYMERS AND POLYMER/CLAY NANOCOMPOSITES Approved by: Dr. David G. Bucknall, Co-advisor Dr. Donggang Yao School of Polymer, Textile and Fiber School of Polymer, Textile and Fiber Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Yonathan S. Thio, Co-advisor Dr. Kenneth Gall School of Polymer, Textile and Fiber School of Materials Science and Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Haskell W. Beckham School of Polymer, Textile and Fiber Engineering Georgia Institute of Technology Date Approved: October 22, 2010 To the everlasting love and support of my Dad, my Mom, my Sister and my Husband… ACKNOWLEDGEMENTS First and foremost, I would like to express my gratitude to my advisors, David Bucknall and Yonathan Thio who gave me an opportunity to work with them as their student at GaTech. They supervised me with their knowledge and experience throughout my time at GaTech, especially when things were tough. It was a great experience to work with them. I would like to thank - Drs. Beckham, Yao and Gall for serving on my dissertation committee and for their most valued inputs. I would like to thank all of them once more for allowing me to use their lab space and equipment whenever I needed.
    [Show full text]
  • Complexation of Cationic Polymers with Nucleic Acids for Gene Delivery
    Complexation of Cationic Polymers with Nucleic Acids for Gene Delivery A thesis submitted to the University of Manchester for the degree of Doctor of Philosophy in the Faculty of Engineering and Physical Sciences 2014 Amy Freund School of Physics and Astronomy 3 Abstract The prospect of gene delivery for therapeutic purposes has created much hope for the treatment and prevention of diverse illnesses, both inherited and environmental. One major challenge for the realisation of this potential is the availability of a suitable vector for trafficking foreign DNA into a cell. Many viruses are effective but carry unacceptable risks of dangerous host immune response or infection. Cationic polymers have been identified as promising candidates to neutralise the DNA's negative charge and gain entry to the cell. In this work a structural study was conducted on a range of established and novel cationic polymer vectors in complexation with nucleic acid molecules for gene delivery. The high neutron flux of the recently available SANS2D instrument on the second target station at the ISIS pulsed neutron source was used in conjunction with a stopped-flow apparatus to study the static and kinetic structure of aggregates of complexes formed between different architectures and molecular weights of polyethylenimine, a commonly used, highly cationic polyelectrolyte, and nucleic acids. Findings indicated the stability of high molecular weight branched polyethylenimine was superior to any other architecture studied. Subsequently, the zeta potential of these polymers complexed with biologically relevant siRNA molecules was studied, which suggested was established that aggregation still proceeds, even with the most apparently stable of the complexes.
    [Show full text]
  • Optical Probe Diffusion in Polymer Solutions
    Optical Probe Diffusion in Polymer Solutions George D. J. Phillies∗ Department of Physics, Worcester Polytechnic Institute, Worcester, MA 01609 The experimental literature on the motion of mesoscopic probe particles through polymer solutions is systematically reviewed. The primary focus is the study of diffusive motion of small probe particles. Comparison is made with measurements of solution viscosities. A coherent description was obtained, namely that the probe diffusion coefficient generally depends on polymer concentration ν 0.8 as Dp = Dp0 exp(−αc ). One finds that α depends on polymer molecular weights as α ∼ M , and ν appears to have large-M and small-M values with a crossover linking them. The probe diffusion coefficient does not simply track the solution viscosity; instead, Dpη typically increases markedly with increasing polymer concentration and molecular weight. In some systems, e.g., hydroxypropylcellulose:water, the observed probe spectra are bi- or tri-modal. Extended analysis of the full probe phenomenology implies that hydroxypropylcellulose solutions are characterized by a single, concentration-independent, length scale that is approximately the size of a polymer coil. In a very few systems, one sees re-entrant or low-concentration-plateau behaviors of uncertain interpretation; from their rarity, these behaviors are reasonably interpreted as corresponding to specific chemical effects. True microrheological studies examining the motion of mesoscopic particles under the influence of a known external force are also examined. Viscosity from true microrheological measurements is in many cases substantially smaller than the viscosity measured with a macroscopic instrument. I. INTRODUCTION ticles are recorded. Historically, Brown used particle tracking to study This review treats probe diffusion and related methods the motion now called Brownian.
    [Show full text]
  • Open Agmcdermott - Dissertation
    The Pennsylvania State University The Graduate School Department of Materials Science and Engineering SCATTERING AND PHYSICAL AGING IN INTRINSICALLY MICROPOROUS POLYMERS A Dissertation in Materials Science and Engineering by Amanda Grace McDermott 2013 Amanda Grace McDermott Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2013 The dissertation of Amanda Grace McDermott was reviewed and approved* by the following: James Runt Professor of Materials Science and Engineering and Polymer Science Dissertation Advisor Chair of Committee Coray M. Colina Associate Professor of Materials Science and Engineering and Corning Faculty Fellow Ralph H. Colby Professor of Materials Science and Engineering and Chemical Engineering Scott T. Milner Joyce Chair and Professor of Chemical Engineering Joan M. Redwing Professor of Materials Science and Engineering, Chemical Engineering, and Electrical Engineering Chair, Intercollege Graduate Degree Program in Materials Science and Engineering *Signatures are on file in the Graduate School iii ABSTRACT Polymers of intrinsic microporosity (PIMs) form glassy, rigid membranes featuring a large concentration of pores smaller than 1 nm, a large internal surface area, and high gas permeability and selectivity. Porosity in these materials—closely related to free volume— arises from an unusual chain structure combining rigid segments with sites of contortion. Linear PIMs can be easily solution-cast into films whose interconnected networks of micropores can be exploited for applications such as gas separation and storage. Like other glasses, though, PIMs are subject to physical aging: a slow increase in density over time. This is accompanied by a decrease in permeability that reduces their performance as gas separation membranes.
    [Show full text]
  • Small- Angle X-Ray Scattering Study of Crazing in Bulk Thermoplastic Polymers
    Small-Angle X-ray Scattering Study of Crazing in Bulk Thermoplastic Polymers Gregory John Salomons A thesis submitted to the Department of Physics in conformity with the requirements for the degree of Doctor of Philosophy Queen's University Kingston, Ontario, Canada January 1998 Copyright @ Gregory John Salomons, January 1998 I VQbIU11611 LIU@UI J uiriiu., i".,"" ..u..rri r-.- of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. rue Wellington Ottawa ON KIA ON4 OttawaON K1AON4 Canada Canada Your ifk, Votre relërence Our file Notre réUrence The author has granted a non- L'auteur a accorde une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/^ de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or othenvise de celle-ci ne doivent être imprimes reproduced without the author's ou autrement reproduits sans son permission. autorisation. Abstract Crazing is a form of tension-induced deformation consisting of microscopic cracks spanned by load-bearing fibrils. This is generally considered to be the primary source of plastic strain response of rub ber-rnodified thermoplastics subjected to applied tensile stress.
    [Show full text]