Direct Liquid Phase Exfoliation of Graphite to Produce Few-Layer Graphene by Microfluidization

Graphene has attracted a great number of attentions due to the excellent physical and chemical properties. For the convenience of investigations and applications, it is crucial to produce the grapheme with high-quality and high-yield by an easy-obtained method. In this research, a promising method is demonstrated to produce a high-concentration few-layer graphene (FLG) dispersion by direct microfluidization in water/surfactant systems. The effects of surfactant selection, chamber pressure and microfluidization cycles on the graphitic material exfoliation efficiency are systematically studied. The FLG concentration and the quality of the as-prepared FLG were determined by a series of characterizations. The graphene dispersions, with an average lateral size of 0.6 mu m and a few-layer structure, were stabilized by surfactants at a high concentration of up to 1.7 mg/mL and exhibited a relatively high quality (I-D/I-G = 0.07-0.56, C/O similar to 19.36) within a processing time of a few hours. This method should facilitate the mass production of high-quality graphene by liquid-phase exfoliation and promote the industrial application of graphene.