Fabrication and Characterization of PVDF-Ba0.8Ca0.15Zr0.1Ti0.9O3 (BCZT)
Composite Films

Abstract

In recent years significant attention has been focused on development of ferroelectric ceramic-polymer composite for flexible capacitor and piezoelectric energy harvesting device applications. In those applications either high permittivity or high piezoelectric property of the ceramic phase was utilized. Polymer is preferred due to their ease of fabrication, cost effectiveness and flexibility.
Present thesis comprises preparation of ferroelectric ceramic-polymer composite films by solu-tion casting method, consisting of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) particles*in*the form of fillers and PVDF polymer as matrix material. In this regard we prepared BCZT powder by two different*routes*namely by solid*state route*via planetary milling (PM) and molten salt syn-thesis (MSS) route. Increase in ceramic volume fraction within*the*matrix, resulted in the im-provement of dielectric properties. However, incorporation of ceramic phase resulted in poor tensile properties of the composite. Planetary milled samples showed maximum value of relative permittivity at 50vol% of BCZT filler that is 47 & tan δ is 0.4. With the increase of ceramic content we observed the depressed peak of PVDF polymer and beyond certain extent this peak completely diminishes. Tensile strength can be retained up to 20 vol% of BCZT. FESEM images showed homogeneous distribution of filler in the matrix, increase in filler volume fraction results in agglomerate formation and settling of particles in the matrix. Films prepared by using plane-tary milled powder showed better mechanical properties. On the other hand, films prepared using molten salt route were showing much improved dielectric properties. Such deviation in the be-havior of the films is due to the morphology of ceramic powder.
In order to improve the properties of the films multi wall carbon nano tube (MWCNTs) were in-corporated into the ceramic polymer composite, which improved dielectric and mechanical prop-erties of composite.