P[CF3(CF2)5CH2MA-co-MMA] and P[CF3(CF2)5CH2MA-co-BA] Copolymers: Reactivity Ratios and Surface Properties

This study aimed at reducing the surface energy of coatings by copolymerization of commonly used monomers with fluorine-containing monomers. Copolymers of 1,1-dihydroperfluoroheptyl methacrylate (FHMA) and methyl methacrylate (MMA) or butyl acrylate (BA) are prepared by low-conversion polymerization in solution. Using 1H-NMR data and nonlinear least-squares data fitting, reactivity ratios of these systems at 80°C are determined to be rFHMA = 1.31, rMMA = 0.76, and rFHMA = 3.15, rBA = 0.38, respectively. We assume that the penultimate unit effect plays an important role in these systems. Introduction of the perfluoroalkyl side chain lowers the polymer surface energy significantly; copolymers of MMA and FHMA show a reduction in total surface energy of about 50 % at a content of 15 mol % FHMA as compared with pure PMMA. The attainable reduction in surface energy is much larger than with, for example, Teflon. This is due to the preferential adsorption of the - CF3 groups of the fluoroalkyl side chain, if compared to that of the - CF2 - groups of Teflo