Enhancement of dielectric properties and AC electrical conductivity of nanocomposite using poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) filled with graphene oxide

Abstract

Synthesis of a new nanocomposite composed of poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) copolymer and graphene oxide (GO) was successfully achieved using solution casting technique. Dielectric properties of the nanocomposite were investigated in the frequency range (10 Hz to 10 MHz) over the temperature range (298–373 K). Many variables such as: dielectric constant, dielectric loss, loss tangent, electric moduli and AC conductivity were studied with changing frequency and temperature, showing improvement in the nanocomposite properties with both of them. The non-Debye behaviour of the samples was confirmed from the electric modulus analysis. AC conductivity (σac) was found to follow Jonscher’s universal power law. The enhancement in (σac) with frequency and temperature has implied the presence of free charge carriers that pass by hopping through defect sites over the potential barriers separating them in the PVVH/GO matrix. The correlated barrier hopping (CBH) model was found to be the best choice for describing AC conduction mechanism in the current nanocomposite over the above temperature range. Scaling of (σac) carried out for the prepared samples has exhibited that charge carriers within the current matrix follow a common conduction mechanism. A comparison between maximum barrier height and activation energy has been carried out to demonstrate the charge carriers transport mechanism. The PVVH-based nanocomposite with the highest concentration of GO (4 wt%) has achieved the highest enhancement in (σac) and mechanical properties, suggesting the feasibility of using it in designing electrochemical and energy storage devices.