Synthesis of Poly(N-isopropylacrylamide)-Block-Poly (tert-Butyl Methacrylate) Block Copolymer by Visible Light-Induced Metal-Free Atom Transfer Polymerization

摘要

Atom transfer radical polymerization (ATRP) is one of the most powerful methodologies for polymerization. Well-controlled ATRP of N-isopropylacrylamide (NIPAAm) could be obtained in organic-water mixture solvent with conventional metal catalyst/ligand catalyst system. However, the mixture solvent is not suitable for copolymerization of NIPAAm with hydrophobic monomers. Moreover, further purification of metal was required for biomedical polymerization. Here, poly(N-isopropylacrylamide) (PNIPAAm) is synthesized by visible light-induced metal-free ATRP using a photoredox catalyst. PNIPAAm is obtained with high conversion and controlled molecular weight with low dispersity. Moreover, poly(N-isopropylacrylamide)-block-poly(tert-butyl methacrylate) (PNIPAAm-b-PMAA) block copolymer can be synthesized by such metal-free ATRP. PNIPAAm-b-PMAA can be obtained by following hydrolysis.