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 non-solvent induced phase separation techniques is presented. Processing parameters such as copolymer volume fraction, solvent, preset exposure time to air before immersion, and non-solvent 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 non-porous films were obtained. The morphology variations strongly influence sample hydrophobicity and mechanical properties. All samples crystallize in the electroactive β-phase with a degree of crystallinity around 30 %.

This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2013 and PEST-C/ QUI/UIO686/2013 and the project Matepro –Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER- 000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). V.F.C. thanks the FCT for the SFRH/BPD/98109/2013 grants.