Graphene is a 2D material with outstanding properties like the strongest, lightest, most conductive and transparent material in the world resulting cutting-edge applications. Any part of applications are outcomes of study of graphene derivatives, and graphene water dispersion is an influential derivative. However, it is hard to disperse graphene in water, but there are many approaches found in the past decades to disperse it not only in water but also in other solvents.
G. Bepete, E. Anglaret, L. Ortoloni, V. Morandi, A. Pénicaud, C. Drummond, Surfactant-Free Single Layer Graphene in Water, 2017.
The percentage of graphene by weight in water effect the properties of graphene water dispersion and usage. Generally concentrations from 7% to 40% by weight is prefered. If the percentage of graphene nanoparticles in dispersion is 10-15% by weight, the dispersion provide increase of thermal and electrical conductivity, and improved gas barrier effect, increase in impermeability, and improvement of the mechanical dynamic properties. If the percentage is 20-30% by weight, one can achieve also increase in thermal and electrical conductivity, gas and liquid barrier effect. In order to achieve not only increase in thermal and electrical conductivity, but also liquid barrier effect, EM and IR shielding, 40% of graphene concentration is used. Each range of concentrations used in many particular applications.
As an application, graphene water dispersion is used in tires as additive of elastomeric composition to obtain rolling resistance, dissipation of heat and electrostatic energy, and gas barrier effect which is crucial to decrease the deflation of tires. Another application is that it is used as component of paints and silicon composites to reach anticorrosion and antifouling effect.
Although dispersibility of graphene prevents applications to enhance, dispersion methods of graphene are categorized as physical dispersion methods, covalent bonding methods, and noncovalent bonding methods. These dispersion methods come with disadvantage which causes defects in graphene and bring other components like surfactants, so the physical and chemical properties of dispersion is not as good as predictions. In the future, new and more efficient dispersion methods will be developed, the cost will be reduced, and properties will be enriched resulting brand-new applications.