An analogous ellipse equation for describing the coupling relationship of friction and adhesion between a probe tip and graphene

摘要

Frictional and adhesive properties of two-dimensional (2D) materials play a key role in determining the performance of micro-nano electromechanical systems (M/NEMS). In this study, a coupling relationship between the lateral force (F-1) and the adhesive force (F-a) of a probe tip sliding on graphene is investigated by molecular dynamics (MD) simulations and a continuum modeling approach. Our results show that the coupling effect of van der Waals (vdW) interactions (between tip/graphene and graphene/substrate) and the bending energy of graphene dominate the coupling relationship. An analogous ellipse equation is proposed to describe the coupling relationship between the interfacial friction and adhesion based on the periodic interaction potential between a probe tip and the lattice of graphene, which is independent of the probe tip type. This study should be of great importance for understanding the interaction mechanism between probe tips and 2D materials on different substrates.