Copolymers of vinylidene fluoride with functional comonomers and applications therefrom: Recent developments, challenges and future trends

The radical copolymerization of VDF with M monomer, the properties and applications of the resulting copolymers are presented. First, after listing a non-exhaustive series of comonomers and macromonomers, and their reactivity towards VDF deduced from the kinetics of copolymerizations to suggest a reactivity order. This review proposes non-exhaustive examples of conventional and controlled (RDRP) radical copolymerization. Other parameters to control these reactions were exposed, such as initiators including specific radicals (e.g., °CF3, °OCF3 and borane radicals), as well as various reaction media (aqueous, solution and supercritical CO2). Crosslinking of these VDF-based copolymers bearing peculiar functions is also useful to enhance the properties of such fluorinated materials. In addition, environmental concerns on such copolymers regarding their persistency are established but more recent studies claim that these macromolecules are polymers of low concern because of the high molar masses and thermal, chemical, photochemical, hydrolytic, inertness and biological stability to satisfy the regulatory assessment criteria. In that way, more recent studies on the mineralization of poly(VDF-co-M) copolymers under subcritical water led to fluoride anions which could react onto Calcium to yield CaF2 to close the loop of these fluorinated copolymers. Finally, several applications are supplied showing that these copolymers are key actors in our daily life (functional coatings, elastomers, thermoplastic elastomers, distillation membranes, and materials for Energy such as electrolytes for Lithium ion batteries, fuel cell membranes, sensors, actuators, dye sensitized solar cells and photovoltaics).