Inverse Miniemulsion Photoiniferter Polymerization for the Synthesis of Ultrahigh Molecular Weight Polymers

Abstract

We describe the synthesis of ultrahigh molecular weight water-soluble polymers via photoiniferter polymerization under inverse miniemulsion conditions. The catalyst-free heterogeneous process is mediated using low-intensity UV irradiation and offers rapid polymerization rates, excellent molecular weight control, polymer end-group fidelity, temporal control, advanced architectures, and most notably, viscosity control. We refined the polymerization conditions by considering the nature of the surfactant, costabilizer, and iniferter agent to achieve acrylamido homopolymers and block copolymers of molecular weights exceeding 1,000,000 Da at ambient temperature. This approach to well-defined ultrahigh molecular weight polymers overcomes the complications of high viscosity to facilitate eventual scale-up.