Photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization using titanium dioxide

Photoinitiated living radical polymerization has attracted wide attention in recent years. Titanium dioxide (TiO2) is a kind of semi-conducting metal oxide which is widely used in water treatment, photovoltaics and organic synthesis. However, there is few application in living radical polymerization. In this study, photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization of methyl methacrylate (MMA) using TiO2 as photoredox catalyst is successfully carried out. It offers good control over molecular weights and polydispersities (PDI). The end group fidelity of PMMA is successfully demonstrated by chain extension for the preparation of poly(methyl methacrylate)-b-poly(dimethylaminoethyl methacrylate) (PMMA-b-PDMAEMA) copolymer. Moreover, the polymerization can be controlled by switching “ON” and “OFF” the light.[graphic not available: see fulltext]