A highly stable aliphatic backbone from visible light-induced RAFT polymerization for anion exchange membranes

Abstract

Polyolefin-based anion exchange membranes have recently been increasingly studied, but obtaining polyolefins with controllable molecular weights and high chemical stability under facile and metal-free conditions remains a critical challenge. Here, we demonstrate a novel strategy of exploiting visible light-induced reversible addition–fragmentation chain transfer polymerization (Vis-RAFT) for the preparation of poly(2-chloroethyl vinyl ether) (PCEVE), which exhibits high alkaline stability. With this strategy, we can control the molecular weight of PCEVE by an “on/off” light procedure. The quaternization of PCEVE yields quaternized poly(2-chloroethyl vinyl ether) (PQEVE) membranes with a well-defined microphase-separated morphology, a high chloride conductivity of 26.1 mS cm⁻¹ at 30 °C, and a significantly reduced water swelling of 1.2% at 80 °C. We anticipate that this strategy can be a potent alternative to metal-catalysed coordination polymerization or metathesis polymerization in preparing high molecular weight polyolefins for membrane applications.