Photoenzymatic RAFT Emulsion Polymerization with Oxygen Tolerance

Abstract

Photoenzymatic reversible addition-fragmenatation chain transfer (RAFT) emulsion polymerization, surfactant-free or ab initio, of various monomers is reported with oxygen tolerance. In surfactant-free emulsion polymerizatoin, poly(N, N-dimethylacrylamide)s were used as stabilizer blocks for emulsion polymerization of methyl acrylate, n-butyl acrylate and styrene, producing well-defined amphiphilic block copolymers, including those with an ultrahigh molecular weight, at quantitative conversions. The controlled character of surfactant-free emulsion polymerization was confirmed by kinetic studies, chain extension studies and GPC analyses. Temporal control was demonstrated by light ON/OFF experiments. In ab initio emulsion polymerization of methyl acrylate and methyl methacrylate, low-dispersity hydrophobic polymers were synthesized with predictable molecular weights. This study extends the monomer scope suitable for photoenzymatic RAFT polymerization from hydrophilic to hydrophobic monomers and demonstrates that oxygen-tolerance can be equally achieved for emulsion polymerization with excellent RAFT control.