Enhancement of electroactive β phase crystallization and dielectric constant of PVDF by incorporating GeO2 and SiO2 nanoparticles

Abstract

Poly(vinylidene fluoride) (PVDF) nanocomposites are recently gaining importance due to their unique dielectric and electroactive responses. In this study, GeO₂ nanoparticles/PVDF and SiO₂ nanoparticles/PVDF nanocomposite films were prepared by a simple solution casting technique. The surface morphology and structural properties of the as-prepared films were studied by X-ray diffraction, scanning electron microscopy, and FT-IR spectroscopy techniques. The studies reveal that the incorporation of GeO₂ or SiO₂ nanoparticles leads to an enhancement in the electroactive β phase fraction of PVDF due to the strong interactions between the negatively charged nanoparticle surface and polymer. Analysis of the thermal properties of the as-prepared samples also supports the increment of the β phase fraction in PVDF. Variation of dielectric constant, dielectric loss, and ac conductivity with frequency and loading fraction of the nanoparticles were also studied for all the as-prepared films. Dielectric constant of the nanocomposite films increases with increasing nanofiller concentration in PVDF. 15 mass% SiO₂-loaded PVDF film shows the highest dielectric constant, which can be attributed to the smaller size of SiO₂ nanoparticles and the homogeneous and discrete dispersion of SiO₂ nanoparticles in PVDF matrix.