The effects of conductive nano fillers alignment on the dielectric properties of copolymer matrix

Abstract

This research focuses on the improvement of the dielectric and energy harvesting properties of piezoelectric P(VDF-TrFE) copolymer matrix by the alignment of conductive reduced graphene oxide nano fillers. The dispersion and the morphology of the conductive nano fillers on the co-polymer matrix were characterized by scanning electron microscopy which showed a configurational phase transition due to highly conductive nano channel formation, steric hindrance, excluded volume interaction van-der-walls forces between adjacent reduced graphene oxide sheets. Five different piezoelectric nanocomposites were prepared by varying the reduced graphene oxide contents in P(VDF-TrFE) matrix to realize its optimum concentration in the matrix. From our analysis, we observed that, an optimized morphological structure plays a vital role in the formation of polar electroactive β phase on the co-polymer matrix through the good dispersion, filler alignment and interfacial interaction of reduced graphene oxide nano fillers. The as prepared nanocomposite film showed an enhanced crystallinity (50 ∼ 52%), dielectric constant (72 at 1 kHz), piezoelectric charge constant (−23 pC/N) with an output power of 3.2 µW at 1.8 MΩ load for 2 N mechanical force. All the outputs were observed without applying poling process. We expect that our synthesized self-poled nanocomposite can be a useful candidate for energy harvesting applications.