SET-LRP of semifluorinated acrylates and methacrylates

Abstract

Single electron transfer-living radical polymerization (SET-LRP) of 1H,1H,2H,2H-perfluorooctyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, and 1H,1H,5H-octafluoropentyl methacrylate up to [M]₀/[I]₀ = 30 and 1H,1H,5H-octafluoropentyl acrylate up to 93% monomer conversion targeting [M]₀/[I]₀ = 260 with excellent control of molecular weight and molecular weight distribution was accomplished in 2,2,2-trifluoroethanol (TFE) at 25 °C for the acrylates and 50 °C for the methacrylate. These experiments demonstrated that TFE serves as a very good solvent for SET-LRP of semifluorinated monomers using hydrazine activated Cu(0) wire as a catalyst, bis(2-bromopropionyl)ethane and p-toluene sulfonyl chloride as initiators, and Me₆-TREN as a ligand. Analysis of the kinetics of polymerization and of the polymer chain ends by a combination of ¹H-NMR, GPC, MALDI-TOF and chain-end functionalization by “thio-bromo” click reaction demonstrated the synthesis of perfect or near-perfect chain-end functional semifluorinated homopolymers.