Dielectric properties of Poly(vinylidene fluoride) / CaCu3Ti4O12 composites

TL;DR

This study demonstrates that incorporating CaCu3Ti4O12 into PVDF significantly enhances the composite's dielectric constant, achieving values up to 95 at room temperature and 190 at elevated temperature, with stable dielectric loss below 40% CCTO loading.

Contribution

It introduces a melt-mixed PVDF/CCTO composite with high dielectric constant and analyzes its properties using multiple models, advancing polymer-ceramic dielectric materials.

Findings

Dielectric constant increases with CCTO volume fraction across frequencies.

Dielectric loss remains stable up to 40% CCTO loading.

High dielectric constant of 95 at 100Hz achieved with 55% CCTO.

Abstract

The possibility of obtaining relatively high dielectric constant polymer-ceramic composite by incorporating the giant dielectric constant material, CaCu3Ti4O12 (CCTO) in a Poly(vinylidene fluoride) (PVDF) polymer matrix by melt mixing and hot pressing process was demonstrated. The structure, morphology and dielectric properties of the composites were characterized using X ray diffraction, Thermal analysis, Scanning Electron Microscope, and Impedance analyzer. The effective dielectric constant of the composite increased with increase in the volume fraction of CCTO at all the frequencies (100 Hz to 1MHz) under study. The dielectric loss did not show any variation upto 40 % loading of CCTO, but showed an increasing trend beyond 40%. The room temperature dielectric constant as high as 95 at 100Hz has been realized for the composite with 55 Vol % of CCTO, which has increased to about 190 at 150oC. Theoretical models like Maxwells Clausius Mossotti, Effective medium theory, logarithmic law and Yamada were employed to rationalize the dielectric behaviour of the composite and discussed. Keywords: A. Ceramic; A. Polymer matrix composite