Inspired from nature, polymeric materials that respond to pH, ionic strength, light, temperature, and other external stimuli represent an important category of materials synthesized by reversible addition fragmentation transfer (RAFT) polymerization.The focus of this study is on the self-assembly behavior in aqueous solutions of pH responsive amphiphilic diblock copolymers. 2-(Dimethylamino)ethyl methacrylate (DMAEMA)/styrene diblock copolymers with different hydrophilic block/hydrophobic block ratios were successfully synthesized via RAFT polymerization. The self-assembly properties of the diblock copolymers were studied by light scattering based techniques (automatic continuous mixing and dynamic light scattering) and transmission electron microscopy. Due to the hydrophilic/hydrophobic interactions, in aqueous environment, the copolymers undergo pH-dependent self-assembly, forming core-shell polymeric micelle-like structures, with styrene block being the hydrophobic core, stabilized by the hydrophilic DMAEMA corona.The way the polymer conformation was affected by the change in pH and ionic strength, stability, aggregation/micellization phenomena were correlated to the degree of polymerization and block lengths of the components. The size of the polymeric structures and their response to the pH of the environment can be tuned by adjusting the block copolymer composition, molecular mass and degree of hydrophobicity.

pH dependent self-assembly behavior of amphiphilic diblock copolymers by RAFT studied by light scattering-based methods

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.