TITLE: Designing Hydrogel Microspheres from Liquid-Liquid Phase Transitions of Aqueous Polymer Solutions

This thesis focuses on reactive water-soluble polymers suitable for forming liquid-liquid phase transitions from both polyelectrolyte complexation and thermal induction. Novel hydrogel microspheres are formed by liquid-liquid phase transition followed by crosslinking reactions. Besides studying the properties of polymers and hydrogel microspheres formed, the mechanism of liquid-liquid phase transitions as well as potential applications of these systems in protein separation and encapsulation are discussed. Chapter 1 describes the background of liquid-liquid phase transitions of aqueous polymer solutions, including polyelectrolyte complexation, thermally induced phase transition and their application in designing hydrogel microspheres. Chapter 2 describes the thermo-responsive properties of fully MPEG-grafted maleic anhydride copolymers in aqueous solutions. The phase transitions are ascribed to the cooperative effects of intra/intermolecular hydrogen bonding and hydrophobic interactions. Chapter 3 describes the use of analogous partially MPEG-grafted malei