Facile synthesis of dual-responsive thioether-bridging graft copolymers by combination of controlled polymerization and thio-bromo click reaction

Abstract

Synthesis of stimuli-responsive exact graft polymers with multisegmented backbone and well-controlled grafting density can provide us with insights into structure-property correlations as well as multipurpose applications in smart materials. Given the great potential of stimuli-labile linkages in materials science, this study describes synthesis of thermo/oxidation-responsive poly(N-isopropylacrylamide)-graft-poly(ε-caprolactone) copolymers via consecutive RAFT process, thio-bromo click reaction and ring-opening polymerization. The cloud point of various graft copolymers was liable to enhance with decreasing chain length of PCL grafts and oxidation of thioether groups. Thermo and oxidation stimuli enabled the formation of distinct morphologies involving micelles and their clusters, necklace-like micelles, vesicles, and their mixtures. A robust method is developed to achieve graft copolymers comprising oxidizable and hydrolyzable backbone, which allows for further researches on special functions and applications of multicleavable smart materials.