Co-Solvency in Liquid Exfoliation of Layered Materials

The extraordinary physical properties of layered inorganic materials have become a tremendous breakthrough in prominent electronic related applications. Due to the growing number of application in these materials, simple methods that produce high quality in larger quantities are highly desired. This thesis describes a novel method in exfoliating the layered inorganic materials with versatile solvents via co-solvency approach. This research demonstrates how mixtures of different common solvents with water could significantly improve the exfoliation of layered materials compared to its pure solution. The most efficient solvent mixtures for exfoliating the layered materials are those with the co-solvent in larger molecular size and surface energy close to that of the nanosheets. For all the solvent mixtures examined in this study, solvent mixtures that best exfoliate the materials tends to have co-solvent/water mixing ratio that gives surface tension of 22–28mN/m in the case of exfoliating graphene and 22–30mN/m for MoS2. The solvent mixtures are ranked in the following trend that based on their exfoliation ability: tert-Butanol-Water > Isopropanol-Water > Ethanol-Water > Acetonitrile-Water > Methanol-Water. Finally, the exfoliated materials are fabricated into thin film via interfacial solution process.