Wetting Property of the Edges of Monoatomic Step on Graphite: Frictional-Force Microscopy and ab Initio Quantum Chemical Studies

Abstract

In this work, we present the wetting property of the edges of a monatomic step on graphite. We have used frictional force microscope to experimentally investigate the wetting property of these edges. We have carried out quantum chemical calculations on a model system of nanographene to characterize hydrogen-bonding interactions between water and two different edges of the graphene, namely, the zigzag and arm-chair edges, to explain our experimental results. We have clearly observed two distinct frictional properties along the monatomic steps on graphite surface under varying conditions of humidity. The distinct frictional properties of the edges have been attributed to the different wetting properties associated with two different edges. Our subsequent quantum chemical calculations complement experimental findings with edge-specific graphene–water interaction.