PVDF Phase Formation and Its Influence on Electrical and Structural Properties of PZT-PVDF Composites

Abstract

The aim of the study is to find the role of lead zirconate titanate (PZT) in the phase formation of poly vinylidene fluoride (PVDF) and its effect on electrical and structural properties of PZT-PVDF composites (50 Vol%) with 0–3 connectivity. PZT particles of different sizes ranging from micron to nano are used. The particle size (<100 nm) were determined from TEM and the broadening of the characteristic diffraction peaks in the x-ray diffraction (XRD) pattern. Scanning electron microscopy (SEM), studies were performed to analyze the nature of ceramic particle distribution within the matrix. The percentage of polymer crystallinity was determined from differential scanning calorimetry (DSC) and found to decrease with decrease in ceramic particle size. The decrease in the crystallinity percentage is due the hindrance offered by ceramic during the crystallization of the polymer. The melting endotherms of the composites were deconvoluted and the amount of PVDF β-phase present in the composites were determined and was found to decrease with decrease in ceramic particle size. Fourier transform infrared spectroscopy (FTIR) studies were also carried out to confirm the decrease in the β-phase content with decrease in particle size. The variation in the amount of β-phase of the polymer is due to the presence of PZT which acts as a source of electric field during poling and converts other polymer phases to β-phase. The piezoelectric coefficient and remnant polarization was found to decrease with decrease in ceramic particle size and is due to the decrease in percentage of β phase in the composites.