One-pot synthesis of PTFEMA-b-PMMA-b-PTFEMA by controlled radical polymerization with a difunctional initiator in conjugation with photoredox catalyst of Ir(ppy)_3 under visible light

摘要

Visible-light-induced free radical polymerization of methyl methacrylate (MMA) and 1,1,1-trifluoroethyl methacrylate (TFEMA) with a difunctional initiator, dimethyl 2,6-dibromoheptanedioate (DMDBHD), conjugated with a photoredox catalyst, tris(2-phenylpyridinato)iridium(III) (fac-[Ir(ppy)_3]), is investigated. Kinetic studies demonstrate that homopolymerizations of both MMA and TFEMA are controlled radical polymerizations. The linear increase of molecular weights with monomer conversion and the narrow PDIs (1.2-1.4) reveal a good living character. In addition, PTFEMA-b-PMMA-b-PTFEMA triblock copolymer is prepared by a one-pot process with sequential monomer addition. The M?n of the triblock copolymers increases linearly with monomer conversion and the PDI of block copolymers is still maintained around 1.2-1.4. Experimental data confirm that the products are pure block polymers. Furthermore, the molar fraction of the TFEMA monomeric unit in the block copolymer is about 21.96%, close to the theoretical value 21.00% calculated from the monomer conversion.