Ferroelectric ceramic dispersion to enhance the beta phase of polymer for improving dielectric and ferroelectric properties of the composites

Abstract

Ferroelectric ceramic-polymer composites consisting of Poly Vinyledine Fluoride-Hexa Fluoro Propylene (PVDF-HFP) as polymer host and 0.5Ba(Zr0.2Ti0.8)O-3-0.5(Ba0.7Ca0.3)TiO3(BZT-BCT) ceramics as filler were prepared using solution casting technique. These composites are characterized for structural, microstructural, vibrational, optical, dielectric and ferroelectric properties at various experimental conditions. The electroactive beta phase fraction (observed from XRD and FTIR analysis) increases as the filler concentration increases up to 20 wt% of BZT-BCT and above that its value decreases. FTIR results were analyzed to understand the mechanism of enhancement of beta phase by the interaction between negatively surface charged ions of filler with the CH(2)dipole of polymer matrix. UV-visible spectroscopy also employed to confirm polymer-ceramic filler interaction. Variation of the dielectric constant with different filler concentrations is explained using the percolation theory. Finally, the interplay between the functional properties and the beta phase is discussed in detail