Fabrication of lead zirconate titanate-based polyvinylidene fluoride polymer nano-composites: microcrystalline, morphological and electrical studies

Abstract

Lead zirconate titanate (PZT) nanoparticles were prepared by the sol-gel process followed by the hydrothermal method. The as-prepared PZT showed Pb(Zr0.52Ti0.48)O-3 phase which was successfully incorporated into a polyvinylidene fluoride (PVDF) polymer matrix by a simple solvent casting method. The X-ray diffraction and field emission scanning electron microscopy (FESEM) results showed phase purity and formation of PZT nanoparticles composited along with alpha and beta-phase PVDF polymer. The dielectric properties of PZT-PVDF nano-composites were evaluated in detail concerning different frequencies and it was observed that the dielectric constant and dielectric loss tangent increased with the PZT content. Mixing a moderate amount (0.5 wt%) of PZT into the PVDF matrix not only enhances the dielectric constant of the matrix but also encourages the transformation of the PVDF crystal from alpha-phase into beta-phase. These effects can improve the dielectric constant, conductivity, and dielectric loss with good dielectric stability. Room temperature dielectric measurement of 0.5PZT-PVDF composites at 30 kHz gives 10-11 times higher electrical conductivity compared to neat PVDF. Besides, it is found that dielectric permittivity values at the lower frequency are affected by space charges while in the higher frequencies the influence of relaxation effect in the materials was observed. It was realized that 0.5PZT-PVDF polymer matrix can withstand optimum temperature and the DSC thermogram exhibited good endothermic peak. Our experimental results reveal that the dielectric parameters like real, imaginary modulus and dielectric loss have a strong frequency reliance.