Applying Control of Heterogeneity Within Atom Transfer Radical Polymerization

This work explores the application and control of heterogeneity within ATRP. The term “heterogeneity” can be applied to polymers in many ways however, this dissertation focuses on molecular weight distribution (MWD) and copolymer composition. The first chapter reviews not only controlled radical polymerizations (CRPs) but also current research on heterogeneity within CRPS, including methods to reduce or purposefully incorporate MWD into polymers as well as advances made to intricate copolymer compositions such as sequence controlled or gradient copolymers. Chapters II and III discuss avenues to reduce MWD values in homogeneous and heterogeneous media, respectively. Dual initiating systems are utilized to provide well controlled polymerizations of methyl acrylate in Chapter II while Chapter III details the synthesis of new active yet hydrophobic ligands for use in ARGET ATRP miniemulsion polymerizations. On the other hand, work in Chapter IV focuses on synthesizing block copolymers with broad MWD through the manipulation of catalyst concentration in ARGET ATRP. Chapter V utilizes the concepts and procedures of Chapter IV to generate gradient copolymers with broad MWD whose quality of gradient architecture is with MWD values. ABA triblock copolymers with disperse center blocks were generated in Chapter VI, however this was not accomplished with ATRP but with polycondensation. From the disperse telechelic macroinitiator synthesized via polycondensation, outer blocks were polymerized under ATRP conditions. The final chapter studies the effects of composition (random, block, and gradient) and topology (linear and star) copolymers utilized as polymeric surfactants in emulsions.