Understanding the friction of atomically thin layered materials

Abstract

Friction is a ubiquitous phenomenon that greatly affects our everyday lives and is responsible for large amounts of energy loss in industrialised societies. Layered materials such as graphene have interesting frictional properties and are often used as (additives to) lubricants to reduce friction and protect against wear. Experimental Atomic Force Microscopy studies and detailed simulations have shown a number of intriguing effects such as friction strengthening and dependence of friction on the number of layers covering a surface. Here, we propose a simple, fundamental, model for friction on thin sheets. We use our model to explain a variety of seemingly contradictory experimental as well as numerical results. This model can serve as a basis for understanding friction on thin sheets, and opens up new possibilities for ultimately controlling their friction and wear protection.

Nanoscale friction and wear of a polymer coated with graphene

“…Nevertheless, we still do not understand the wide variety of different mechanisms at play in such systems. During the last few decades, with the development of the atomic force microscope [8] and increases in computing power, it has become possible to investigate more deeply and develop an understanding of the mechanisms that play a role in the friction of graphene [5,[9][10][11][12][13][14][15][16][17][18][19]. The effect of graphene coatings and their ability to protect against wear depend on the substrate underneath.…”

Thermal effects and spontaneous frictional relaxation in atomically thin layered materials

“…To further the understanding of these materials, atomistic MD simulations have also been performed by a number of groups, (such as [8,9]). However, significant developments were recently made in this area using a simple model [10].…”

“…In this work, we analyse the thermal behaviour of the phenomena of strengthening and layer dependence of the friction of atomically thin sheets using the simple modified Prandtl-Tomlinson (PT) model [15][16][17] that has previously been shown to capture and explain these phenomena [10]. We add thermal noise to this model, and * Electronic address: astrid.dewijn@ntnu.no investigate its effect on the distortion of the sheets and the friction.…”

“…We will begin by introducing and quickly reviewing the model proposed in [10]. Following this, we will discuss how the thermal fluctuations affect the dynamics during sliding.…”

Nano-scale friction and wear of polymer coated with graphene

“…Nevertheless, we still don't understand all the different mechanisms at play in such systems. During the last few decades, with the development of the Atomic Force Microscope [8] and increases in computing power, it has become possible to investigate more deeply and develop understanding of the mechanisms that play a role in the friction of graphene (see, for example [9][10][11][12][13][14][15][16][17][18][19][20][21]). The effect of graphene coatings, and their ability to protect against wear, depends on the substrate underneath.…”