Bio-photo-Fenton-like RAFT polymerization under blue light†

Abstract

In this manuscript, we report a natural photoinitiation system for polymer synthesis by employing a combination of riboflavin 5′-monophosphate sodium salt (vitamin B2) and hydrogen peroxide, and later a glucose/glucose oxidase system, for conducting reversible addition–fragmentation chain transfer (RAFT) polymerization. Under blue LED irradiation (λ = 451 nm), the bioactive form of riboflavin, flavin mononucleotide (FMN), in the presence of hydrogen peroxide was able to initiate the controlled RAFT polymerization of N,N-dimethylacrylamide. The resulting polymer was found to also possess excellent chain fidelity after chain extension via characterization by GPC. The photopolymerization was found to reach a higher conversion in the presence of hydrogen peroxide than without. This feature was exploited by using a glucose/glucose oxidase mixture to produce hydrogen peroxide in situ during the photopolymerization while additionally introducing oxygen tolerance into the system. These results suggest the excellent potential for this mild and oxygen tolerant bio-photo-Fenton photoinitiation system to be applied.