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 b 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 (À23 pC/N) with an output power of 3.2 mW at 1.8 MX 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.

Enhanced Power Generation by Piezoelectric P(VDF-TrFE)/rGO Nanocomposite Thin Film

“…At 10 4 Hz frequency, the dielectric constant value was 17 for the pristine P(VDF-TrFE) film and reached a maximum value of 21 at a rGO concentration of 0.002 wt%. As shown in Figure S1a, this trend can be explained by a model of micro-capacitor formation [43]. In the model, the nanocomposite thin film with the optimum amount (0.002 wt%) of rGO shows higher dielectric constant than that for any other films because rGO particles form proper number of micro-capacitors.…”

“…These two attractive forces of hydrogen bonding and dipolar interaction helped dipole orientation in P(VDF-TrFE) chains in the nanocomposite film of P(VDF-TrFE)/rGO [41,42]. This result of optimum rGO content can be explained in terms of interaction between surface charge due to oxygencontaining functional groups such as C-O, C=O, COO-, OH and delocalized π electrons of rGO and -CH 2 -CF 2 dipoles in polymer chains [15,43]. This interaction accommodates the P(VDF-TrFE)/rGO nanocomposite film to form the β-phase easily.…”