Colloidal Dispersibility of Graphene from the Perspective of Inter- and Intra-particle Interactions

Graphene oxide (GO), one of the graphene derivatives, is well known for having good colloidal stability and dispersibility in some solvents, including water, ethylene glycol, 1-Methylpyrrolidin-2-one, N, N-Dimethyl-formamide. The excellent dispersibility of GO is attributed to the hydrophilic functional group with a negative charge on the surface, and as the hydrophobic graphitic domain extends from the surface, the dispersibility is either maintained or not depending on the solvent.

First, the basic structure and physical properties of GO dispersions in each solvent were investigated. Then, each GO dispersion was mildly heated, which increase a graphitic domain of GO. The change in the dispersibility of GO with mild heating suggests proper processing conditions for GO-based applications such as GO-polymer composites. This study answers the question of the mechanism by which graphene particles are sensitive to certain solvent properties and their interactions with solvents change. This study further answers the question of how the interaction with the solvent in the dispersion of graphene particles varies with the solvent and what is the dispersion mechanism in solutions.