Poly(vinylidene fluoride-trifluoroethylene) Porous Films: Tailoring Microstructure and Physical Properties by Solvent Casting Strategies

A systematic study for the production of porous poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), films using solvent evaporation and nonsolvent induced phase separation techniques is presented. Processing parameters such as copolymer volume fraction, solvent, preset exposure time to air before immersion, and nonsolvent and temperature of the coagulation bath were varied and the corresponding sample morphology, hydrophobicity, thermal, and mechanical properties were determined. Film morphologies including homogeneous pore distributions, micropores, microvoids, spherulites, and nonporous films were obtained. The morphology variations strongly influence sample hydrophobicity and mechanical properties. All samples crystallized in the electroactive β-phase with a degree of crystallinity around 30%.