Enzyme catalysis-induced RAFT polymerization in water for the preparation of epoxy-functionalized triblock copolymer vesicles

Abstract

Enzyme catalysis is a mild and efficient technique that has been widely used in organic chemistry and polymer chemistry. In this work, enzyme catalysis-induced aqueous reversible addition–fragmentation chain transfer (RAFT) polymerization was conducted at room temperature for the preparation of a series of epoxy-functionalized triblock copolymer vesicles. Specifically, poly(glycerol monomethacrylate)-b-poly(2-hydroxypropyl methacrylate) (PGMA-PHPMA) diblock copolymer vesicles were first prepared via enzyme-initiated aqueous RAFT dispersion polymerization, and subsequently used as seeds for chain extension of glycidyl methacrylate (GlyMA) via enzyme-initiated seeded RAFT emulsion polymerization. Nanoscale phase separation was observed at higher degree of polymerization (DP) of PGlyMA. The room temperature feature of enzyme-initiated RAFT polymerization is critical to ensure the survival of epoxy groups after the polymerization. The obtained triblock copolymer vesicles were evaluated as an efficient Pickering emulsifier for hexane-in-water emulsions. In addition, the triblock copolymer vesicles were found to be tolerant to the challenge of surfactant in water. Finally, the epoxy groups in the vesicular membrane were utilized to react with ethylene diamine, allowing the preparation of cross-linked vesicles as well as silver composite vesicles.