Abstract
Synthesis of poly(vinylidene fluoride)-based functional polymers with tunable wettability was achieved viaradical copolymerizations of vinylidene fluoride (VDF) with tert-butyl 2-trifluoromethacrylate (MAF-TBE)followed by hydrolysis of the tert-butyl ester groups. Radical copolymerizations of VDF with 2-trifluoromethylacrylic acid (MAF) and MAF-TBE were investigated under various experimental conditions:initiators, temperatures, and solvents. The polymerizations using peroxide initiators led to good yield(≥57%), while azo initiators did not lead to any polymerization. The compositions and microstructures ofall the obtained copolymers were determined by 1H and 19F NMR spectroscopies. The very low yield(23%) achieved in radical copolymerization of VDF with MAF in water was attributed to the regioselectivenucleophilic addition of water onto MAF, yielding a potential fluorosurfactant, 3-hydroxy-2-(trifluoromethyl)propanoic acid in good yield (85%). In contrast, no reaction was observed between MAF-TBE andwater, even in the presence of ammonium perfluorooctanoate as a (fluorinated) surfactant. Thepoly(VDF-co-MAF-TBE) copolymer was shown to be easily hydrolyzed under mild conditions to prepare–COOH-functionalized PVDF copolymers, without any dehydrofluorination of VDF units. The wettabilitiesof these copolymers were studied by water contact angle (WCA) measurement. Compared to thepoly(VDF-co-MAFTBE) copolymers (WCA = 102°), the –COOH functionalized PVDF copolymer exhibits alower WCA (57°). This work paves the way for the synthesis of PVDF-based functional copolymers withtunable wettability for potential applications in the preparation of membranes for water purification, coatingsor oil recovery systems.