Thermoresponsive property of poly(N,N-bis(2-ethoxyethyl)acrylamide) and its multiblock copolymers with poly(N,N-dimethylacrylamide) prepared by hydrosilylation-promoted group transfer polymerization

Abstract

Poly(N,N-bis(2-ethoxyethyl)acrylamide) (PEOEAm), a new thermoresponsive polyacrylamide, has been studied from the perspectives of synthesis and thermal phase transition. PEOEAm without any initiator residue at the chain end was synthesized via hydrosilylation-promoted group transfer polymerization (GTP) to exclude the effect of polymer end groups on the thermoresponsive properties of the polymer. To extend thermoresponsive PEOEAm to its copolymer systems, the GTP tendency of EOEAm was evaluated and compared with that of N,N-dimethylacrylamide (DMAm). There exists a significant difference between the polymerization reactivities of EOEAm and DMAm, and this difference was applied to realize the random group transfer copolymerization (GTcoP) of EOEAm (“A” unit) and DMAm (“B” unit) for the one-pot synthesis of a BA-block copolymer. A series of block copolymer architectures, such as AB-, ABA-, BAB-, and BABA-block copolymers, were similarly prepared. The thermoresponsive properties of the block copolymers were evaluated by measuring the cloud-point temperature and hydrodynamic radius of their aqueous solutions.