Base Catalyzed Thiol–Ene Click Chemistry toward Inner CHCF Bonds for Controlled Functionalization of Poly(vinylidene fluoride)

A facile and controlled base catalyzed thiol–ene click chemistry toward electron-deficient CHCF double bonds in poly(vinylidene fluoride) PVDF (P(VDF-DB)) is reported in present contribution for the first time. The addition reaction is carefully conducted under varied conditions including at the elevated temperature, in the different solvents, and with the altered catalysts and thiols. The addition reaction is well confirmed to follow the base catalyzed route and exhibits close dependence onto the reaction conditions. Besides the addition reaction, the other two side reactions catalyzed by alkylamines, including the further main chain degradation of P(VDF-DB) substrates together with the nucleophilic substitution of thiols to CHCF units, can be completely avoided by choosing a catalyst with a proper pK_a value. With respect to the universality and well controlled feature of the reaction, the low cost and readily prepared P(VDF-DB) substrate and the mild reaction conditions, this strategy may offer a robust tool for attaching various functional groups into PVDF side chain.