Atomic-scale friction in graphene oxide: An interfacial interaction perspective from first-principles calculations

摘要

Atomic-scale friction in graphene oxide is investigated using density functional theory calculation including a long-range dispersion correction (DFT-D). The sliding behaviors between two graphene oxide layers with different functional groups or oxidation levels are quantitatively studied based on the constructed potential energy surfaces. Sliding paths with minimum energy corrugations and the corresponding static lateral forces and shear strengths for different systems are derived, suggesting moderately higher friction in graphene oxide compared with graphene. The effects of load on friction in different graphene oxide models are also investigated. Moreover, the largest lateral force existing in the graphene oxide system with both epoxide and hydroxyl groups is dominated by the interlayer hydrogen bond interaction, the instability of which also simultaneously leads to dissipation and hence gives rise to the friction. An in-depth understanding of the relationship between atomic-scale friction and interfacial interactions reveals that certain levels of friction can be achieved by controllable structural and chemical modifications to the sliding surfaces, which sheds light on friction control and design of new lubricant materials.