Increased electroactive properties of poly(vinylidene fluoride) films by thermo-mechanical post-processing

Abstract

Due to its outstanding electroactive properties, poly(vinylidene fluoride) (PVDF) is widely used in the energy, electronic, and biomedical fields. In particular, the highly polar and electroactive β-phase obtained by low temperature solvent evaporation has numerous technological applications due to its piezo-, pyro- and ferroelectric properties, but typically presents a porous morphology. PVDF membranes were prepared by non-solvent induced phase separation (NIPS) from a dimethylformamide (DMF) solution, and post-processed by thermo-mechanical compression under varying temperature and pressure to produce solid films. The effect of these parameters on the morphology, β-phase content, thermal properties, crystalline phase content and piezoelectric response was evaluated. Thermo-mechanical treatment reduces porosity leading to a compact morphology, while also increases the βphase content and the degree of crystallinity. Also, it enhances the mechanical properties and increases the piezoelectric value. It is to notice that this simple processing method is compatible with the large-scale manufacturing of electroactive PVDF samples in an industrial setting.