Wetting characteristics of vertically aligned graphene nanosheets

Vertically aligned graphene nanosheets (VAGNs) are a class of graphitic carbon in which few layers of graphene nanosheets are aligned perpendicular to the plane of the substrate. The change in water contact angle (from 103° to 135°) with VAGNs, as a function of change in the surface geometry, is analysed. Theoretical calculations and comparison with the experimental data shows that the apparent contact angle values of VAGNs are closer to that of the fully non-wetting mode or ideal Cassie mode of wetting. The ideal Cassie mode of wetting also explains the variation of the water contact angle of VAGNs with the surface morphology of the material and predicts how surface parameters can be modified to get the required wettability for a certain application of this material.