Photoenzymatic RAFT Emulsion Polymerization with Oxygen Tolerance

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.

Automated summary

This study demonstrates the oxygen tolerance of surfactant-free or ab initio photoenzymatic reversible addition-fragmenatation chain transfer (RAFT) emulsion polymerization for various monomers, producing well-defined amphiphilic block copolymers with ultrahigh molecular weight. The controlled character of surfactant-free emulsion polymerization and the synthesis of low-dispersity hydrophobic polymers in ab initio emulsion polymerization were confirmed through kinetic studies, chain extension studies, and GPC analyses. Temporal control and extension of suitable monomers for photoenzymatic RAFT polymerization from hydrophilic to hydrophobic monomers were also achieved in this study.