Anionic Polymerizations of Perfluoroalkyl Methacrylates and Synthesis of Well-Defined ABC Triblock Copolymers of Methacrylates Containing Hydrophilic, Hydrophobic, and Perfluoroalkyl Groups

Abstract

Anionic polymerizations of three perfluoroalkyl methacrylates, 2,2,2-trifluoroethyl- (1), 2-(perfluorobutyl)ethyl- (2), and 2-(perfluorooctyl)ethyl methacrylates (3), were carried out in THF at −78 °C for 1 h with 1,1-diphenyl-3-methylpentyllithium in the presence of 5-fold lithium chloride. Poly(1) and poly(2) were obtained in quantitative yields and those possessed predicted molecular weights based on the molar ratios of monomers and initiator and narrow molecular weight distributions (MWD, Mw/Mn<1.15). Polymerization of 3 also proceeded quantitatively to give poly (3) showing very limited solubility. Sequential anionic copolymerizations of 2, tert-butyl methacrylate (tBMA), and 2-(trimethylsilyloxsy)ethyl methacrylate and the subsequent deprotection of trimethylsilyl group afforded a series of well-defined ABC triblock copolymers by changing the additional order of three comonomers. 1H NMR spectra of the resulting triblock copolymers suggested the formation of their micelles in the selective solvents. Contact angle and X-ray photoelectron spectroscopic measurements of the triblock copolymer films confirmed the enrichment of the poly(2) segment at the film surface in dry state and the surface rearrangement in respect to changing the environmental conditions. It was suggested that segmental sequence in the triblock copolymers affected the structure in solution and at surface.