Frictional behavior of strained multilayer graphene: Tuning the atomic scale contact area

Graphene is an ideal material to study nanoscale friction and modulating its frictional behavior is significant for the development of graphene-based micro- and nanoelectromechanical systems. Recently, strain engineering has been used to tune numerous properties of graphene. However few attentions have been paid to the strain effect on the frictional behavior of graphene. In this study, molecular dynamics simulations were carried out to study the friction coefficient of a strained multilayer graphene during scratching process under different scratch depths. It was found that the friction coefficient decreased under tensile strain while it increased under compressive strain. Further analysis of the atomic scale contact area was conducted to clarify the mechanism of such strain dependence. The results showed that the numbers of contacting atoms decreased as the strain increased from -8% to 8%. which was consistent with the friction coefficient variations under the applied strain. Therefore, the strain-dependent friction was attributed to the atomic scale contact area variations under the applied strain. This work shed light on the development of strain-based method to control nanoscale friction. (C) 2016 Elsevier B.V. All rights reserved.