Surfactant assisted dispersion of graphene in aqueous solution using mixed surfactants

In this work, graphene is initially dispersed in surfactant sodium dodecyl sulfonate (SDBS) in an aqueous solution. Sonication followed by centrifugation is the process used to disperse the graphene in an aqueous solution with the aid of SDBS. The concentration of graphene is determined using UV–Vis-NIR spectroscopy. A higher concentration of graphene is achieved just above the critical micelle concentration of SDBS in an aqueous solution. To further improve the concentration of graphene in an aqueous solution of SDBS, a second surfactant polyvinyl pyrrolidone (PVP) is used. The mixed surfactant strategy has increased the concentration of graphene in an aqueous solution by ∼ 400% as compared to SDBS aided dispersion of graphene in an aqueous solution. Atomic force microscopy (AFM) observations reveal the few-layer dispersion of graphene in an aqueous solution with the aid of mixed surfactants; while SDBS assisted dispersion of graphene in an aqueous solution shows the few layers to 10 s of layers of graphene nanosheets.