A Facile Visible-Light-Induced Route to Functionalize Polymeric Substrates by Combining Controlled Radical Grafting Polymerization and Thiol−Yne Click Chemistry with Photoredox Catalyst Ir(ppy)3

A novel strategy, based on surface-initiated grafting polymerization and post-polymerization thiol-yne click chemistry, with Ir(ppy) 3 as a sole photoredox catalyst, under visible light irradiation is developed. The “livingness” of the grafting polymerization is demonstrated by the linear increase of the graft yield with irradiation time and the block grafting polymerization. Then, acetenyl groups of poly(propargyl methacrylate) (PPMA) grafting chains are reacted with pentaerythritoltetra-(3-mercaptopropionate) via the thiol-yne click reaction. The successful introduction of reactive thiol groups onto the low-density polyethylene- graft -poly(propargyl methacrylate) (LDPE- g -PPMA) films is demonstrated by Fourier transform IR (FTIR) and X-ray photoelectron spectra (XPS) spectroscopy, and the thiol-ene click reaction with N -(1-pyrenyl) maleimide.