Enhanced Electroactive Phases in Bi3·3La0·7Ti3O12-poly (vinylidene fluoride) composites with Improved Dielectric Properties

Abstract

Lead-free ceramic-polymer nanocomposites comprising poly (vinylidene fluoride) (PVDF) and homogeneously dispersed Bi3·3La0·7Ti3O12 (BLT) ceramic particles were synthesized using the solution casting method. The effect of BLT addition on the growth rate of different crystalline phases of PVDF was systematically investigated. X-ray diffraction analysis showed the presence of β-phase in all the composite samples. FTIR and Raman spectroscopy analysis also confirmed the enhancement in the electroactive β and γ phases with BLT addition. The fraction of β-phase i.e., F(β)% has been found to be 64.5% at 10 wt % BLT loading. The homogeneous distribution of ceramic particles in PVDF matrix was confirmed using field emission scanning electron microscopic analysis. The dielectric constant of the nanocomposites with 10 wt % of BLT loading can reach up to 53.5 at 100 Hz, which is attributed to the enhanced interfacial polarization and relative enhancement of electroactive phases of PVDF. The temperature-dependent dielectric measurement shows an enhancement in the dielectric constant with increasing temperature. The nanocomposites also exhibit excellent ferroelectric properties with enhancement in remanent polarization. This work suggests the possibility of enhancing the electroactive phases of PVDF with superior dielectric and ferroelectric properties. These lead-free nanocomposites may prove to have a tremendous potential in flexible sensors, data storage, and energy harvesting applications.