Nano to micrometer range particle size effect on the electrical and piezoelectric energy harvesting performances of hydroxide mediated crosslinked PVDF composites

The polar phase and piezoelectric response of filler-loaded PVDF-based composites very often depend on the interfacial interaction between the filler surface and PVDF dipoles. In this regard, hydrogen bonding interaction has shown a much stronger effect compared to other interactions. In order to induce hydrogen bonding interaction, the filler surface is commonly modified by various modifiers. In the present work, instead of filler surface modification, we introduce ZnSn(OH)6 filler (hydroxide filler having a high number of –OH groups) into the PVDF matrix in order to facilitate the hydrogen bonding interaction. Not only the hydroxide fillers but the effect of wide particle size variation (from nano to micrometer range) into PVDF has also been shown here for the very first time. ZnSn(OH)6 fillers with similar morphology but different sizes have been synthesized by using a variety of techniques and then incorporated into the PVDF matrix. The microstructural defects of the composite films have been found to be gradually increased with the increase in filler size which in turn caused to gradually increase their space charge polarization. Filler, with 915 nm size has shown the best polar phase formation (∼84 %), dielectric permittivity (∼10 at 1 kHz), and piezoelectric energy harvesting performance (output voltage ∼20 V) of the resulting PVDF-based composite and hence has been used for various real-life applications. All of these results have been suitably explained here on the basis of interfacial interaction, microstructural defect, and the mechanism of formation of space charge polarization.