High-Concentration, Surfactant-Stabilized Graphene Dispersions

A method is presented to produce graphene dispersions, stabilized in water by the surfactant sodium cholate, at concentrations up to 0.3 mg/mL. The process uses low power sonication for long times (up to 400 h) followed by centrifugation to yield stable dispersions. The dispersed concentration increases with sonication time while the best quality dispersions are obtained for centrifugation rates between 500 and 2000 rpm. Detailed TEM analysis shows the flakes to consist of 1-10 stacked monolayers with up to 20% of flakes containing just one layer. The average flake consists of approximately 4 stacked monolayers and has length and width of approximately 1 mum and approximately 400 nm, respectively. These…

• IR
  Irish Research Council for Science, Engineering and Technology
• SF
  Science Foundation Ireland