On the structural, dielectric, piezoelectric, and energy storage behavior of polyvinylidene fluoride (PVDF) thick film: Role of annealing temperature

The optimization of the processing condition of polyvinylidene fluoride (PVDF) plays a pivotal role in determining the structural, dielectric, and energy storage behavior. The present work addresses the effect of annealing on the structural, dielectric, piezoelectric, and energy storage behavior of the PVDF thick film. X-ray diffractogram/Fourier transform infrared spectroscopy/RAMAN reveals the enhancement in the β crystalline phase of PVDF with annealing temperature which is highest for the film annealed at 110 °C. The film annealed at 110 °C exhibited the dielectric constant, dielectric loss, and piezoelectric coefficient as 14.02, 0.05 at 100 Hz and 24 pC/N, respectively. A systematic enhancement of 21% in dielectric constant, 46% in discharge energy density, and 87% in piezoelectric coefficient is reported for the PVDF film annealed at 110 °C as compared to the film annealed at 50 °C. The enhancement in dielectric and energy storage properties is attributed to the alignment of CH₂–CF₂ by virtue of molecular motion in the PVDF chain. This work suggests the adaptation of annealing for modifying the dielectric and energy storage behavior which is momentous for various electronic applications.