Effect of hot press temperature on <i>β</i>-phase, dielectric and ferroelectric properties of solvent casted Poly(vinyledene fluoride) films

Abstract

Poly(vinylidene fluoride) (PVDF) films were prepared by solvent casting at different temperatures (40 °C, 50 °C, 60 °C) and each solvent casted film were hot pressed at 110 °C, 130 °C and 150 °C. The transition of electroactive β-phase from non-polar α-phase is deeply influenced by hot pressing temperature. Phase transition was studied by x-ray diffraction (XRD) and fraction of β-phase was calculated by analyzing Fourier Transform infrared (FTIR) spectra. Differential Scanning Calorimetry(DSC) was performed for all the samples to determine degree of crystallinity. Dielectric constant increased with increase in β-fraction. Remnant polarisation(Pr) and Coercive field(Ec) from ferroelectric hysteresis loop were influenced by both β-fraction and degree of crystallinity.