Controlled RAFT polymerization facilitated by a nanostructured enzyme mimic

Abstract

Recent reports have revealed the potential of nanostructured materials to display enzyme-like activity for a broad range of applications. In this study, a glycine modified metal–organic framework (MOF) MIL-53(Fe) composite was utilized as an enzyme (e.g. peroxidase) mimic for the generation of reactive oxygen species (ROS) from hydrogen peroxide. The resultant hydroxyl radicals can act as initiators in the presence of chain transfer agents and monomers in aqueous or organic media, allowing for controlled polymerization via reversible addition–fragmentation chain transfer (RAFT). The polymer products present controllable molecular weights, narrow polymer dispersities and high ‘livingness’ as revealed by a chain extension experiment and MALDI-ToF analysis. By continuously supplying hydrogen peroxide to the MOF peroxidase mimic, ultrahigh molecular weight polyacrylamides (M_n > 1 MDa) of low dispersity (Đ < 1.25) were also obtained. By incorporating low cost, highly stable and easily isolated peroxidase-mimicking catalysts, glycine modified MIL-53(Fe) represents a versatile synthetic strategy to produce well-defined polymers from both hydrophilic and hydrophobic monomers.