Effect of rGO concentrations on the structural, vibrational, and dielectric properties of PVDF-HFP/rGO composite

Abstract

A series of flexible polymer composite films with rGO as conducting filler and PVDF-HFP as polymer matrix having general formula: PVDF-HFP + φ wt% rGO (φ = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0) are prepared by solution casting technique. The structural, vibrational and dielectric properties of the composite films are studied as a function of rGO concentration. XRD analysis shows that the β phase fraction increases with the increase of rGO concentrations up to φ = 1.5wt% and after that its value decreases. The dielectric constant of the composites also increases with increase in filler concentrations and the maximum value of dielectric constant is observed for φ = 1.5 wt% similar to the variation of β phase fraction in XRD data. There is an enhancement of the dielectric constant of two times for φ = 1.5 wt%. i.e., 17 at 10 kHz as compared to the pure polymer matrix PVDF-HFP (ϵr = 8). FTIR analysis suggests that the interactions between the carboxyl functional group of rGO sheets with fluorine atom of PVDF-HFP is responsible for the enhancement of β phase which is well correlated with XRD study. The work shows that the polymer composite could be useful as flexible sensor or self-powered devices.