Mechanisms of Strain-Dependent Interlayer Dynamic Friction in Graphene

Two-dimensional materials have now become the main components of nanoelectromechanical systems due to their outstanding properties in practical application. This study investigates dynamic friction between rotational graphene layers under equi-biaxial tensile and shear strain via molecular dynamics simulations from the perspective of energy dissipation. To eliminate the influence of commensurability and the edge effect, a friction pair model with annular graphene as a slider is established. The mechanisms of strain effect coupling with temperature, rotational frequency, and supporting stiffness on the interlayer friction are analyzed. The results indicate that tensile strain reduces interlayer friction, while the shear strain effect on friction varies with temperature. The mechanism of frictional dissipation is explained from the perspectives of interface moiré pattern, entropic effect, interatomic interactions, effective contact atoms, in-plane deformation, out-of-plane lattice vibration, and phonon state density. The results of the research will provide a theoretical basis for the design and manipulation of nanoelectromechanical systems and two-dimensional materials.