Controlled Synthesis of Fluorinated Copolymers via Cobalt-Mediated Radical Copolymerization of Perfluorohexylethylene and VinylAcetate

International audience: Designing novel polyfluoropolymer architecturesis attractive for the development of new applications, such asadvanced coatings, purification membranes, or materials forenergy. Nevertheless, controlling the radical polymerization offluoroalkenes is very challenging due to the high reactivity of thepropagating fluorinated macroradicals. This study aims atexploring the controlled copolymerization of perfluorohexylethylene(PFHE) and vinyl acetate (VAc) in order toprepare a range of well-defined statistical poly(PFHE-stat-VAc)copolymers with different compositions. Cobalt-mediated radicalpolymerization demonstrated to be active at 40 °C starting froman alkylcobalt(III) initiator, and copolymers with a fluorinated monomer content as high as ca. 80 wt % were successfullyprepared. Reactivity ratios were determined to be rVAc = 0.18 and rPFHE = 0 at 40 °C and emphasized a clear tendency foralternation. Unprecedented PFHE/VAc containing block copolymers were also prepared via a single-step approach or throughsequential copolymerizations. Finally, hydrolysis of the pendant ester groups of these copolymers led to the correspondingfluorinated copolymers bearing vinyl alcohol (VOH). A preliminary solution behavior study, carried out by dynamic lightscattering and transmission electron microscopy on block copolymers composed of PFHE and VAc or VOH units, evidenced amarked amphiphilicity of the copolymer composed of an extremely hydrophobic PFHE block associated with a highlyhydrophilic PVOH segment