Synthesis and Property of Photo- and Temperature-Dual-responsive Amphiphilic Block Copolymers

Photo- and temperature-responsive amphiphilic block copolymers, poly(ethylene glycol)-b-poly {(N-isopropylacrylamide-co-6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate), denoed as PEO-b-P(NIPAM-co-MAZO), were designed and synthesized by atom transfer radical polymerization (ATRP). The macroinitiator based on poly(ethylene glycol) (PEG, M-n, = 2000 Da) was utilized to initiate the copolymerization of N-isopropylacrylamide (NIPAM) and 6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate (MAZO). The resultant copolymers, combining photo-responsive moieties with thermal-responsive moieties, possess photo- and temperature- dual-responsive property, among of which, PNIPAM shows lower critical solution temperature (LCST) and PMAZO exhibits reversible trans-cis isomerization under UV/vis irradiation. In selective solution they can form selective micro-tunnel with excellent controlled release, and can be used as drug carrier and controllable membrane.