The preparation and electrical properties of the functionalized graphene/poly (ether sulfone) nanocomposites

Chemical functionalized graphene (f-G) was obtained by the reaction of the residual epoxide and carboxyl functional groups on the hydrazine-reduced graphene (G) sheets with hydroquinone. The efficacy of the functionalization reaction of graphene was confirmed by X-ray photoelectron spectroscopy and thermogravimetric analysis. Atomic force microscopy and transmission electron microscopy images showed that the functionalized graphene can be easily exfoliated into functionalized graphene nanosheets composed of single or bilayers of graphene sheets. The f-G was used to prepare conductive poly (ether sulfone) (PES) composites (f-G/PES) via the solution casting method and the alternating current (AC) and direct current (DC) properties of f-G/PES composites were investigated. It was observed that good dispersion of f-G nanosheets in PES matrix resulted in a low percolation threshold of 0.355 vol.%. Hopping type of charge transport occurred during the insulator-semiconductor transition of f-G/PES composites. Impedance measurement was carried out to evaluate interfacial capacitance of the composites, and the interfacial capacitance of the composites increased to 1041.9 pF of f-G/PES composites with 5 wt.% f-G from 30.48 pF of f-G/PES composites with 0.5 wt.% f-G.