Simultaneous enhancement of mechanical, electrical and thermal properties of graphene oxide paper by embedding dopamine

Reduced graphene oxide paper was fabricated by incorporating dopamine. By using adhesive property, reducing ability, high thermal stability, and high carbon-yielding characteristic of dopamine, the dopamine-embedded graphene oxide paper can be mechanically stronger, thermally more stable, and electrically more conductive compared to conventional graphene oxide paper. Herein, in order to preserve a planar structure of graphene sheets and obtain free-standing paper, a simple one-step fabrication method was introduced, in which vacuum-assisted filtration of a graphene oxide suspension and polymerization of dopamine proceed at the same time. The manufactured paper had sequentially layer-stacked and planar structure of graphene sheets and polydopamine. The paper showed increased tensile strength and elongation, and higher thermal stability. Electrical conductivity was recovered, which was not measurable in conventional graphene oxide paper. To investigate enhancement of reduction, thermal annealing was further carried out. As a result, a critical reduction temperature was lowered and higher electrical conductivity was recorded at all annealing temperatures.