Precision control of temperature response by copolymerization of di(ethylene glycol) acrylate and an acrylamide comonomer.

Abstract

The readily tuned thermoresponsive behavior of well-defined statistical and block copolymers of di(ethylene glycol)ethyl ether acrylate (DEGA) and N,N-dimethylacrylamide (DMA) was investigated. DEGA and DMA were copolymerized with various comonomer feed ratios by reversible addition–fragmentation chain transfer (RAFT) polymerization. Reactivity ratios were determined, which allowed copolymers with precisely tuned compositions to be prepared. The cloud point of the resulting copolymers was observed to vary linearly with the mole fraction of hydrophilic DMA over the range of 10–90 °C. Block copolymers of DEGA were also prepared by chain extension of poly(DEGA) homopolymers with DMA. The resulting block copolymers formed well-defined polymeric micelles when heated above the cloud point of the poly(DEGA) block. Thus, copolymerization of DEGA was shown to be a convenient route to thermoresponsive polymers with specific and predictable transition temperatures.