Influences of out-of-plane elastic energy and thermal effects on friction between graphene layers

Abstract

Through molecular dynamic simulations, a system for investigating the contributions of elastic deformation energy and thermal activation effects to friction has been constructed. In this system, a graphene flake slides on a suspended graphene layer anchored on a bed of springs. The “graphene–spring” system provides a useful ideal approach to model different layers of graphene through changing the stiffness of the springs. The results first indicate that both the friction force and the elastic deformation energy have an exponential dependence on the support stiffness. Second, the observed non-monotonic variation in friction manifested by peaks and plateaus with increasing temperature results from the changing rate of energy dissipation due to the transition of slip regimes. Therefore, we suggest that the friction force emanates from the competition between the interfacial energy barrier and out-of-plane elastic deformation energy, as well as the competition between the thermal activation effects and transition of slip regimes. Therefore, the observation can extend the validity of the Prandtl–Tomlinson model on friction phenomena. Our simulations are intended to provide theoretical guidance when considering the influence of stiffness on the friction between graphene layers in the design of nanodevices.

Tuning the interfacial friction force and thermal conductance by altering phonon properties at contact interface

“…This is similar to the concept of thermal lubrication [51][52][53]. Our simulation implies that the matching degree of phonon modes at the interface is one of the main factors to influence the friction force, besides the commensurability [6, 54-57], thermal activation [53,58], and sliding velocity [9,59].…”

Ultrasonic Characterization of Nanoparticle-Based Ceramics Fabricated by Spark-Plasma Sintering

“…An important parameter for the internal friction is the activation energy, which is the energy needed for triggering a thermally activated dissipative process. As shown by [24,25], the internal friction in graphene sheets is exponentially increasing with temperature, which indicates that it is a thermally activated process, as also discussed in [26]. Here we measure the temperature dependence of the internal friction of BNNS-and BCN-based materials and compare the results with those obtained for the GNP-based material.…”

Molecular dynamics simulation of lateral ultrasonic excitation in atomic-scale friction

“…Tribology is an ancient and important discipline, which involves friction, adhesion, lubrication and wear between surfaces or interfaces in relative motion. Controlling friction and reducing dissipation have long been pursued for many researches [1][2][3][4][5]. At the macro scale, gears and bearings and liquid lubricants can reduce friction, but these methods may fail at the micro-or nanoscale [5].…”