Oxygen Tolerance Study of Photoinduced Electron Transfer-Reversible Addition-Fragmentation Chain Transfer (PET-RAFT) Polymerization Mediated by Ru(bpy)3Cl2

This study reports a highly efficient photoredox catalyst, Ru(bpy)(3)Cl-2, capable of controlling the polymerization of methacrylates, acrylates, and acrylamides in the presence of thiocarbonylthio compounds via a photoinduced electron transfer-reversible addition-fragmentation chain (PET-RAFT) process. This polymerization technique was performed in a closed vessel in the presence or absence of air. Online Fourier transform near-infrared spectroscopy (FTNIR) was employed to monitor the monomer conversions of methyl methacrylate, methyl acrylate, and N,N'-dimethylacrylamide in the presence or absence of air. Interestingly, after an induction period, the polymerization proceeded in the presence of air to yield well-defined polymers (PDI < 1.20). The polymers were characterized by H-1 NMR, UV-vis spectroscopy, and gel permeation chromatography. Excellent end-group retention was also demonstrated by NMR, UV-vis, and successive chain extensions of the resulting homopolymers to yield diblock and multiblock copolymers (decablock copolymers).