Well-Structured Random Copolymers Bearing Anionic and Cationic Pendants and Their Tunable Thermo-responsive Behavior in Aqueous Solution

摘要

Thermo-responsive polymers have potential applications in various fields like drug delivery, bio-separation, sensors and so on. 1 Herein, we present the controlled synthesis of styrene-type amphoteric random copolymers with cationic vinylbenzyltrimethylammonium chloride (VBTAC) and anionic sodium styrenesulfonate (NaSS) (P(VBTAC/NaSS)n;; n = 20 and 97) via reversible addition-fragmentation chain transfer (RAFT) polymerization method (Fig. 1a). 4-Cyano pentanoic acid dithiobenzoate was used as a chain transfer agent. NaCl aqueous solution/methanol mixture was used as a polymerization solvent. These polymers showed upper critical solution temperature (UCST) type phase transition in NaCl aqueous solutions based on charge interactions.