Download or read book Synthesis and Aqueous Solution Studies of Stimuli responsive Block Copolymers Synthesized by Reversible Addition fragmentation Chain Transfer Polymerization written by Anthony Joseph Convertine and published by . This book was released on 2006 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Stimuli responsive Block Copolymers Via Reversible Addition fragmentation Chain Transfer Polymerization written by Brent Sterling Sumerlin and published by . This book was released on 2003 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Hydrogel Forming Thermo responsive Block Copolymers of Increasing Structural Complexity written by Anna Miasnikova and published by . This book was released on 2012 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Polymerization Reactions written by Wayne F. Reed and published by John Wiley & Sons. This book was released on 2014-01-21 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers new strategies to optimize polymer reactions With contributions from leading macromolecular scientists and engineers, this book provides a practical guide to polymerization monitoring. It enables laboratory researchers to optimize polymer reactions by providing them with a better understanding of the underlying reaction kinetics and mechanisms. Moreover, it opens the door to improved industrial-scale reactions, including enhanced product quality and reduced harmful emissions. Monitoring Polymerization Reactions begins with a review of the basic elements of polymer reactions and their kinetics, including an overview of stimuli-responsive polymers. Next, it explains why certain polymer and reaction characteristics need to be monitored. The book then explores a variety of practical topics, including: Principles and applications of important polymer characterization tools, such as light scattering, gel permeation chromatography, calorimetry, rheology, and spectroscopy Automatic continuous online monitoring of polymerization (ACOMP) reactions, a flexible platform that enables characterization tools to be employed simultaneously during reactions in order to obtain a complete record of multiple reaction features Modeling of polymerization reactions and numerical approaches Applications that optimize the manufacture of industrially important polymers Throughout the book, the authors provide step-by-step strategies for implementation. In addition, ample use of case studies helps readers understand the benefits of various monitoring strategies and approaches, enabling them to choose the best one to match their needs. As new stimuli-responsive and "intelligent" polymers continue to be developed, the ability to monitor reactions will become increasingly important. With this book as their guide, polymer scientists and engineers can take full advantage of the latest monitoring strategies to optimize reactions in both the lab and the manufacturing plant.
Download or read book Aqueous Reversible Addition fragmentation Chain Transfer Polymerization of Functional Monomers and Their Incorporation Into Stimuli responsive Amphiphilic Block Copolymers written by Bradley Steward Lokitz and published by . This book was released on 2007 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stimuli Responsive Gels written by Dirk Kuckling and published by MDPI. This book was released on 2018-10-11 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Stimuli-Responsive Gels" that was published in Gels
Download or read book Design Synthesis and Application of Stimuli responsive Block Copolymers written by Muhammad Rabnawaz and published by . This book was released on 2013 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the preparation of novel multi-responsive and multiply stimulable triblock copolymers. The resultant polymers were used to coat cotton fabrics and glass to render them amphiphobic. Further, a method was developed for the preparation of poly(ethylene glycol)-block-poly(hydroxyethyl methacrylate) (PEG-b-PHEMA) via anionic polymerization. The multi-responsive copolymer refers to poly(ethylene glycol)-orthonitrobenzyl-poly[2-(perfluorooctyl)ethyl methacrylate)-block-poly(2-cinnamoloxyethyl methacrylate) (PEG-ONB-PFOEMA-b-PCEMA, or P1). P1 was synthesized via atom transfer radical polymerization (ATRP) of FOEMA and a precursory monomer of CEMA using a PEG macroinitiator. The copolymer was multi-responsive or dual light-responsive because the ONB junction cleaves and PCEMA block becomes crosslinked upon UV photolysis. The multiply stimulable copolymers are a series of poly(ethylene glycol)-disulfide-poly[2-(perfluorooctyl)ethyl methacrylate)-block-poly(2-cinnamoloxyethyl methacrylate) (PEG-S2-PFOEMA-b-PCEMA) copolymers. These polymers were synthesized by the end-coupling Py-S2-PFOEMA-b-PHEMA and PEG-SH, and subsequent cinnamation of the PHEMA block. These polymers are multiply stimulable because the S2 junction and PCEMA block respond to different stimulations, such as reducing agents and light, respectively. These synthetic strategies will advance the field of stimuli-responsive polymers by providing novel functional polymers for the generation of durable self-cleaning surfaces. The above polymers form micelles in water or water/organic solvent mixtures because of the water-soluble PEG blocks. Polymer-coated cotton was obtained by immersing cotton in micellar copolymer solutions before subsequent drying and annealing treatment. Upon photolysis, the PEG block was cleaved and the PCEMA anchoring layer became crosslinked. Such a crosslinked and stable layer was rendered amphiphobic because of the exposed PFOEMA block. A similar coating can be obtained from P2. Two types of stimulations including photolysis and reduction treatment need to be applied to yield amphiphobic textiles. This coating strategy is unique and environmentally friendly because the water- and oil-repellent coatings were prepared from an aqueous solution for the first time. In a further study, a novel and long-sought method was developed for the anionic polymerization of PEG-b-PHEMA. A PEG-DPE macroinitiator was synthesized and subsequently converted into an active initiator by reaction with sec-butyl lithium. Consequently, the active initiator underwent polymerization with HEMA-TMS to yield PEG-b-P(HEMA-TMS). Upon post-polymerization modification, PEG-b-PHEMA was obtained with a low polydispersity of 1.08.
Download or read book Synthesis and Characterization of Stimuli Responsive Block Copolymers Self assembly Behavior and Applications written by Michael Duane Determan and published by . This book was released on 2006 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water-soluble stimuli responsive block copolymers are a rapidly emerging class of materials with great potential in biomedical and technological applications. In this work a novel class of pentablock copolymers are synthesized via atom transfer radical polymerization techniques and their stimuli-responsive self-assembly properties are characterized. Aqueous solutions of these materials are observed to form micelles and hydrogels in response to changes in both temperature and pH. Cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron and X-ray scattering (SANS and SAXS) techniques are used to investigate the nanoscale structures formed by these pentablock copolymers in solution. The gel structure and mechanical properties are investigated with SANS and rheological techniques. The multi-responsive properties of these materials are utilized to formulate a stimuli responsive drug delivery formulation that exhibits thermoreversible gelation and pH dependent release rate of model drugs.
Download or read book Self assembly and Gold Nanoparticle Cross linking of Stimuli responsive Block Copolymers Synthesized by Reversible Addition fragmentation Chain Transfer Polymerization written by Adam Eugene Smith and published by . This book was released on 2010 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Solution Behavior of Doubly Responsive Hydrophilic Block Copolymers written by Xueguang Jiang and published by . This book was released on 2010 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the synthesis of stimuli-sensitive hydrophilic polymers, particularly doubly responsive hydrophilic block copolymers, by controlled radical polymerizations and the study of their solution behavior in water. By incorporating a small amount of stimuli-responsive groups into the thermosensitive block of a hydrophilic block copolymer, the lower critical solution temperature (LCST) of the thermosensitive block can be tuned by a stimulus and multiple micellization/dissociation transitions can be achieved by combining two external triggers. Chapter 1 describes the synthesis and thermosensitive properties of two new watersoluble polystyrenics with a short oligo(ethyl glycol) pendant from each repeat unit and the study of hydrophobic end group effects on cloud points of thermosensitive polystyrenics. Well-defined polymers were prepared from monomer-based initiators via nitroxide-mediated polymerization and the alkoxyamine end groups were removed by tri(n-butyl)tin hydride, yielding thermoresponsive polystyrenics with essentially no end groups. The results showed that hydrophobic end groups could significantly change the cloud points and the molecular weight dependences of cloud points of polystyrenics. Chapter 2 presents the synthesis of thermo- and light-sensitive hydrophilic block copolymers, poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate), and their responsive behavior in dilute aqueous solutions. Dynamic light scattering and fluorescence spectroscopy studies showed that these copolymers were molecularly dissolved in water at lower temperatures and self-assembled into micelles at temperatures above the LCST of the thermosensitive block. Upon UV irradiation, the o-nitrobenzyl group was cleaved and the LCST of the thermosensitive block was increased, causing the dissociation of micelles into unimers. The resultant copolymers underwent thermo-induced reversible micellization at higher temperatures. Chapter 3 describes multiple micellization/dissociation transitions of thermo- and pH-sensitive hydrophilic block copolymers, poly(ethylene oxide)-b-poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid), in response to temperature and pH changes. The LCST of the thermosensitive block can be reversibly tuned and precisely controlled by solution pH. Chapter 4 presents the study on multiple sol-gel-sol transitions of a 20.0 wt % aqueous solution of poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate) induced by temperature changes and UV irradiation. The solution underwent thermo-induced sol-gel-sol transitions. Upon UV irradiation to dissociate micelles, the gel was transformed into a free-flowing liquid, which upon heating underwent sol-gel-sol transitions again.
Download or read book Aqueous Micellar Gels of Multiresponsive Hydrophilic ABA Linear Triblock Copolymers written by Jeremiah Wallace Woodcock and published by . This book was released on 2011 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the synthesis of a series of well-defined multiresponsive hydrophilic ABA linear triblock copolymers and the study of their aqueous micellar gels. By incorporating a small amount of stimuli-responsive groups into thermosensitive outer blocks of ABA triblock copolymers, the lower critical solution temperatures (LCST) of thermosensitive blocks can be modified by external stimuli. Consequently, the sol-gel transition temperatures (Ts̳o̳l̳-g̳e̳l̳) of their aqueous solutions can be altered. Chapter 1 describes the synthesis and solution behavior of a series of thermo- and light-sensitive triblock copolymers, poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate)-b-poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate), with different contents of light-responsive o-nitrobenzyl groups. Aqueous solutions of these block copolymers with a 10.0 wt% concentration exhibited thermo-induced sol-gel transitions. Upon UV irradiation, the hydrophobic o-nitrobenzyl groups were cleaved, resulting in an increase in the LCST and consequently gel-to-sol transitions. The UV-irradiated solutions again underwent temperature-induced sol-gel transitions but at higher temperatures. The change of Ts̳o̳̳l̳-g̳e̳l̳ was, in general, larger for the copolymer with a higher o-nitrobenzyl content after UV irradiation. Chapter 2 presents the synthesis of thermo- and enzyme-responsive ABA triblock copolymers, poly(ethoxydi(ethylene glycol) acrylate-co-4-((dihydroxyphosphoryl)oxy)butyl acrylate)-b-poly(ethylene oxide)-b-poly(ethoxydi(ethylene glycol) acrylate-co-4-((dihydroxyphosphoryl)oxy)butyl acrylate), and the enzyme-induced formation of thermoreversible micellar gels from their moderately concentrated aqueous solutions at 37 °C. The dephosphorylation by acid phosphatase decreased the LCST of thermosensitive outer blocks from above to below 37 °C. The enzyme-induced gelation of 7.9 wt % aqueous polymer solutions at pH 4.4 was monitored by rheological measurements. The Ts̳o̳̳l̳-g̳e̳l̳ decreased and the gel strength increased with the increase of reaction time. The gels formed were thermoreversible. Chapter 3 presents the synthesis of two thermo- and pH-sensitive tertiary amine-containing ABA triblock copolymers and the sol-gel transitions of their aqueous solutions with a 10 wt% concentration at different pH values. Chapter 4 describes the use of reversible addition-fragmentation chain transfer (RAFT) polymerization for the synthesis of well-defined thermosensitive polymethacrylates and polyacrylates. Eight chain transfer agents were synthesized. The RAFT polymerizations of alkoxyoligo(ethylene glycol) (meth)acrylates using these chain transfer agents were well controlled, producing well-defined polymers. A summary of this dissertation research and future work are presented in Chapter 5.
Download or read book Synthesis of Amino Functional Monomers Via Controlled Radical Polymerization written by Xeniya Savelyeva and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Controlled radical polymerization (CRP) techniques has allowed the synthesis of numerous polymeric materials with comparable control to that of true "living" techniques without the need for stringent manipulation techniques. The control over chain length, dispersity and composition is desirable in many fields, such as stimuli-responsive (temperature or pH) drug carriers. These thermoresponsive polymers in aqueous media are often characterized by lower critical solution temperature (LCST) behavior, where the polymer becomes insoluble with temperature increases. The LCST can be tuned by the structural features of the constituent monomer, molecular weight, molecular weight distribution and copolymerization with other monomers. Narrow molecular weight distribution is the key factor determining the sharpness needed for determining the LCST, which is often exemplified by the cloud point temperature (CPT). Using CRP techniques, specifically nitroxide mediated polymerization (NMP), with an alkoxyamine unimolecular initiator, 2-([tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]amino]oxy)-2-methylpropanoic acid (BlocBuilder) and an additional free nitroxide (SG1), the effect of controlling comonomer (9-(4-vinylbenzyl)-9H-carbazole (VBK)) on polymerization kinetics of N-(2-methacryloyloxyethyl) pyrrolidone (MAEPYR) and the effect of final copolymer composition on CPT was studied. Adding at least 5 mol% VBK, the dispersity Đ of the poly(MAEPYR-stat-VBK) copolymers was below 1.4. The CPT decreased from 59.0 °C to 49.7 °C with addition of only 1 mol% of VBK in the copolymer, and it can be further fine-tuned by changing the solution concentration and the heating rate. Another CRP technique, reversible addition fragmentation chain-transfer polymerization (RAFT), was applied to homopolymerization of N-(3-methoxypropyl) acrylamide (MPAM) to yield well-defined polymers (with (M_n)− = 14.3 - 25.2 kg mol-1 and low Đ ~ 1.17 - 1.47) needed for precise determination of CPT. Thermoresponsive behaviour of poly(MPAM) in aqueous media revealed CPTs between 73 and 92 °C, unlike other literature reports where the polymers, synthesized by conventional radical polymerization, showed conflicting results regarding their LCST" --
Download or read book Synthesis of Stimuli responsive Polymers Via Nitroxide Mediated Polymerization and Characterization in Aqueous and Ionic Liquid Solutions written by Chi Zhang and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Stimuli-responsive polymers have been touted as "smart" due to their fast and reversible responses to environmental changes. It is imperative for these polymers to have well-defined structures so that their performance can be consistent and predictable. In order to achieve this, nitroxide mediated polymerization (NMP) was employed as the synthesis technique for the microstructured polymers that form the core of the investigations presented in this thesis. As one of the main controlled radical polymerization techniques, NMP stands out for its simplicity in both required ingredients and purification procedures. Many known stimuli-responsive polymers are poly(methacrylates). However, homopolymerization of methacrylates has been challenging for NMP mainly due to the large equilibrium constant that resulted in high concentration of active radicals and thus excessive irreversible terminations. By using a small amount of "controlling co-monomer" such as styrene, copolymerizations with methacrylate-rich feeds can be controlled using the commercially available alkoxyamine initiator BlocBuilderTM via NMP, featuring linear increases in number average molecular weight versus conversion, and narrow molecular weight distribution.In this thesis, two methacrylates, namely 2-(dimethylamino)ethyl methacrylate (DMAEMA) and benzyl methacrylate (BzMA), whose homopolymers exhibit LCST-type phase separation behaviours in aqueous and ionic liquid (IL) solutions, respectively, were copolymerized with various controlling co-monomers by NMP to demonstrate the versatility of NMP in tuning thermo-responsive properties. For both methacrylates, styrene was initially used as the controlling co-monomer to obtain copolymers with relatively narrow molecular weight distribution and ability to extend chains to form block copolymers when reinitiated with a fresh batch of monomer. 2-Vinylpyridine (2VP) was then chosen to copolymerize with DMAEMA for its lower hydrophobicity compared to styrene and pH-sensitivity, where about 2 - 5 mol% 2VP was shown sufficient to obtain well-defined DMAEMA/2VP copolymers. The detailed phase behaviour characterization of these DMAEMA-rich copolymers in aqueous solutions revealed the effects of important factors such as pH, copolymer composition, solution concentration and polymer microstructure, on the tuning of transition temperatures.For BzMA, 9-(4-vinylbenzyl)-9H-carbazole (VBK) was used as an alternative controlling co-monomer. Controlled and pseudo-"living" copolymerizations were achieved with as little as 2 mol% VBK in the feed, demonstrating significant improvement compared to the BzMA/styrene system. The incorporation of fluorescent VBK resulted in 5-fold fluorescence enhancement during the phase separation of BzMA/VBK copolymers from IL [C2mim][NTf2]. The enhancement resulted from heightened efficiency of the fluorescence resonance energy transfer (FRET) between BzMA and VBK during aggregation. However, the solvatophobicity of VBK also significantly reduced the solubility of BzMA/VBK copolymers in the IL and rendered the phase separation irreversible. Further investigation on the effects of solvatophilicity and chain mobility on phase separation and reversibility in ILs was carried out by incorporating varying amounts of solvatophilic co-monomer, namely methyl methacrylate (MMA) and oligo(ethylene glycol) methacrylate (OEGMA), yielding BzMA/MMA/VBK and BzMA/OEGMA/VBK terpolymers. It was found that molecular weight, glass transition temperature, and solution concentration all played important roles on phase separation temperature but sufficiently high solvatophilicity (quantified by the concentration of solvatophilic group) was essential to facilitate the re-dissolution process after phase separation. " --
Download or read book Complex Macromolecular Architectures written by Nikos Hadjichristidis and published by John Wiley & Sons. This book was released on 2011-04-20 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of CMA (complex macromolecular architecture) stands at the cutting edge of materials science, and has been a locus of intense research activity in recent years. This book gives an extensive description of the synthesis, characterization, and self-assembly of recently-developed advanced architectural materials with a number of potential applications. The architectural polymers, including bio-conjugated hybrid polymers with poly(amino acid)s and gluco-polymers, star-branched and dendrimer-like hyperbranched polymers, cyclic polymers, dendrigraft polymers, rod-coil and helix-coil block copolymers, are introduced chapter by chapter in the book. In particular, the book also emphasizes the topic of synthetic breakthroughs by living/controlled polymerization since 2000. Furthermore, renowned authors contribute on special topics such as helical polyisocyanates, metallopolymers, stereospecific polymers, hydrogen-bonded supramolecular polymers, conjugated polymers, and polyrotaxanes, which have attracted considerable interest as novel polymer materials with potential future applications. In addition, recent advances in reactive blending achieved with well-defined end-functionalized polymers are discussed from an industrial point of view. Topics on polymer-based nanotechnologies, including self-assembled architectures and suprastructures, nano-structured materials and devices, nanofabrication, surface nanostructures, and their AFM imaging analysis of hetero-phased polymers are also included. Provides comprehensive coverage of recently developed advanced architectural materials Covers hot new areas such as: click chemistry; chain walking; polyhomologation; ADMET Edited by highly regarded scientists in the field Contains contributions from 26 leading experts from Europe, North America, and Asia Researchers in academia and industry specializing in polymer chemistry will find this book to be an ideal survey of the most recent advances in the area. The book is also suitable as supplementary reading for students enrolled in Polymer Synthetic Chemistry, Polymer Synthesis, Polymer Design, Advanced Polymer Chemistry, Soft Matter Science, and Materials Science courses. Color versions of selected figures can be found at www.wiley.com/go/hadjichristidis
Download or read book Developments in Block Copolymer Science and Technology written by Ian W. Hamley and published by John Wiley & Sons. This book was released on 2004-03-05 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focuses on recent advances in research on block copolymers, covering chemistry (synthesis), physics (phase behaviors, rheology, modeling), and applications (melts and solutions). Written by a team of internationally respected scientists from industry and academia, this text compiles and reviews the expanse of research that has taken place over the last five years into one accessible resource. Ian Hamley is the world-leading scientist in the field of block copolymer research Presents the recent advances in the area, covering chemistry, physics and applications. Provides a broad coverage from synthesis to fundamental physics through to applications Examines the potential of block copolymers in nanotechnology as self-assembling soft materials
Download or read book Handbook of Pyrrolidone and Caprolactam Based Materials 6 Volume Set written by Osama M. Musa and published by John Wiley & Sons. This book was released on 2021-07-06 with total page 2665 pages. Available in PDF, EPUB and Kindle. Book excerpt: HANDBOOK OF PYRROLIDONE AND CAPROLACTAM BASED MATERIALS Brings together, for the first time, a comprehensive review of all aspects of pyrrolidone- and caprolactam-based materials This comprehensive, six-volume set describes the broad technical universe of γ- and ε- lactams, reviewing in-depth the chemistry of the small lactam-based molecules, uncovering their unique properties and showing how they have enabled a myriad of commercially important applications. From synthesis, through production and into applications, this extensive work targets significant and recent trends in γ- and ε-lactam science and technology and addresses all key aspects of pyrrolidone- and caprolactam-based materials to produce a definitive overview of the field. Handbook of Pyrrolidone and Caprolactam Based Materials provides a detailed and modern portrait of the impact of pyrrolidone- and caprolactam-based materials on the world, as well as potential future possibilities. Volume One presents the chemistry of small lactam-based molecules and uncovers their unique properties. Volume Two covers polymeric materials, including polyvinyl pyrrolidone and polyvinyl caprolactam, and reviews homopolymerization, copolymerization, controlled radical polymermization and acrylate based pyrrolidone polymerizations. Volume Three examines the physical chemistry and molecular interactions of pyrrolidone and caprolactam based materials. Volume Four expands upon the characterization theme from the third volume, and includes detailed discussions of nuclear magnetic resonance (NMR) and Fourier transform-infrared (FT-IR) spectroscopy, thermal and mechanical properties, and imaging techniques. Volume Five explores pharmaceutical applications in both ingredients and materials, as well as the antimicrobial properties and applications of pyrrolidone and caprolactam-based materials, and their toxicology. Volume Six covers personal and home care, skin care, transdermal applications and wound care, oral care, adhesion related applications and digital applications such as inkjet technology. Handbook of Pyrrolidone and Caprolactam Based Materials will appeal to industrial scientists and engineers interested in polymer development and manufacturing. It will also benefit academic researchers working in the fields of chemistry, materials science, and chemical and process engineering.
Download or read book Synthesis and Characterization of Ionically Bonded Diblock Copolymers written by Lei Feng (Chemical engineer) and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers consist of two or more incompatible polymer chains linked by covalent bonds. These block copolymer can separate into nanometer sized domains whose morphology depends upon the size of the block and interactions between them. The properties of block copolymers can be modified and potentially improved by introducing noncovalent interactions to replace covalent linkages between blocks to form supramolecular block copolymers. These kinds of materials combine the microphase separation inherent to block copolymers with the facile synthesis of supramolecular materials thereby affording new and unique materials. This dissertation focuses on synthesis and characterization of PS-b-PMA block copolymers with ion-pair junctions.Firstly, the chain-end sulfonated polystyrene ([omega]-sulfonated PS) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization and postpolymerization modification. In the postpolymerization modification two methods were investigated: in the first one, the polymer was converted to a thiol-terminated polymer by aminolysis. Then a sulfonic acid end-group was produced then by oxidation of the thiol end-group with m-chloroperoxybenzoicacid (m-CPBA); in the second method, the RAFT-polymerized polymer was directly sulfonated by oxidation with m-CPBA. After purification by column chromatography, [omega]-sulfonated PS was obtained by both methods with greater than 95% end-group functionality as measured by titration. The sulfonic acid end-group could be neutralized with various ammonium or imidazolium counter ions through acid-base or ionic metathesis reactions. These polymers with ionic end-group can be used as model supramolecular building blocks.Secondly, ammonium end functionalized polymethylacrylate (PMA) was synthesized directly by RAFT polymerization using functional RAFT agent. Then chain-end sulfonated polystyrene and ammonium end functionalized polymethylacrylate (PMA) were used to synthesize A-B block copolymers by two different methods: the first method was by mixing two oppositely charged end group functionalized polymers; the second method was to ionically bond a RAFT agent to the chain end of an end sulfonated polymer to generate a supramolecular macro RAFT agent then an A-B block copolymer was prepared by RAFT polymerization using supramolecular macro-RAFT agent. The polymerization kinetics were investigated and the molecular weight and the chemical structure of the block copolymers were characterized by 1H-NMR and SEC. The results show that the ion-bonded supramolecular block copolymer, PS-PMA, have been successfully prepared with controlled molecular weight and narrow distribution.Thirdly, the morphology of the ion-bonded supramolecular PS-PMA diblock copolymers were investigated by small-angle X-ray scattering (SAXS) and rheological techniques. Several covalently bonded PS-PMA block copolymers were synthesized by RAFT polymerization and their micro domain structures and rheology behaviors were also investigated. The results showed that the electrostatic interactions between the end ion groups are able to overcome the thermodynamic repulsion of two blocks result in the formation of diblock copolymers with similar behaviors and morphology of traditional covalent bonded diblock copolymers and their micro domain structures remain to high temperatures.
