ABSTRACT
The graphene oxide dispersions exhibited long-term stability, consisting of sheets with sizes ranging from hundreds of nm to a few µm, similar to the dispersion of graphene oxide in water. These results provide guidance while selecting solvents to disperse graphene-based materials. One of the critical challenges in using graphene nanosheets for practical applications is the lack of an efficient way to reliably produce them in both large quantities and of high qualities. To disperse graphene oxide, the organic solvents should be polar molecules, because the graphene oxide sheets contain a large quantity of polar oxygen-containing groups, such as hydroxyl, carbonyl, carboxyl, etc., which would trigger a strong graphene oxide sheet–solvent interaction. Graphene oxide nanosheets in the dispersions can be directly converted to graphene nanosheets that can be dispersed in water, without precipitation. The graphene suspensions obtained in this way exhibited very high stability, which made it possible for further processing, such as spin-coating, casting or spraying to take place.
