▎ 摘　　要

We investigate the nanoscale frictional behaviors and characteristics of mono-, bi-, and tri-layer graphene/Cu (111) systems using molecular dynamics simulations. The existence of graphene layers significantly enhances the load carrying capacity, extends the low friction range, and effectively decreases the friction. The friction coefficient depends on the normal force, which is very distinctive in contrast to classic friction laws and shows the nanoscale effect. The stable friction coefficients are 0.24, 0.18, and 0.11 for monolayer, bilayer, and trilayer graphene, respectively. Such distinguishable nanofriction behaviors suggest an experimental routine to characterize the number of graphene layers on copper foil or other substrates through nanoscratching as an alternative approach to Raman spectroscopy. (C) 2016 Elsevier B.V. All rights reserved.