Resistance of UV-perforated reduced graphene oxide on polystyrene surface

UV-perforated reduced graphene oxide flakes of large areas, some of them up to 500 $\mu$m in diameter, have been produced on polystyrene surface. These flakes were formed during precipitation of UV-reduced graphene oxide composites based on polystyrene from benzene solutions by petroleum ether. Two composites based on polystyrene with molecular weights of 9,000 Da and 45,000 Da were synthesized to compare their conductive properties. Conditions of the formation of planar structures from UV-perforated reduced graphene oxide flakes were varied. So, resistances were compared for composites deposited from solutions with different concentrations and at different temperatures. Very low resistances for some flakes precipitated from 5 wt.% solution of composite of 9,000 Da molecular mass at the room temperature were obtained. The absolute values of measured resistances were found to be 1.5 orders of magnitude lower than resistance of copper. At the same time some, regions of graphene inclusions from 12 wt.% solution of latter polystyrene composite demonstrated even lower resistance, almost 3 orders of magnitude lower than copper resistance. This result is explained by existence of superconducting component in the reduced graphene oxide inclusions. In the case of composites with graphene flakes produced from higher molecular weight polystyrene (45,000 Da) resistance was high and varied from semiconducting values to non-conductive state.