Critical Behavior of Electrical Conductivity for Reduced Graphene Oxide/Epoxy Resin Composites

Abstract

In this paper, we analyze the dc and ac electrical conductivities, in the 240 to 400 K temperature range and 10² to 10⁶Hz frequency range, of a percolating system synthesized by mixing reduced graphene oxide (rGO) particles in insulating epoxy resin matrix, diglycidyl ether of bisphenol A (DGEBA). We found that the dc electrical conductivity of the samples is strongly related to the rGO content, indicating a percolating behavior with percolation threshold ϕ_c ≈ 4 %. The critical behavior of the dc electrical conductivity as a function of the temperature indicates a strong positive temperature coefficient and a negative temperature coefficient of resistivity below and above the transition temperature T_g, respectively. Moreover, the results showed that the dc conductivity obeys the Arrhenius law and the ac electrical conductivity is both frequency and temperature dependent and follows the Jonscher’s power law.

Keywords:Composites, Dielectric properties, Fillers, Glass transition, Graphene.