Friction Reduction of Hydrogenated Graphene by Strain Engineering
The pursuit of superlow friction in graphene systems has been a persistent target during the past decade. However, the friction is exhibited a remarkable increase for the chemically modified graphene with hydrogen element. To overcome this problem, both biaxial strain and uniaxial strains are applied on hydrogenated graphene to study the effect of strain on the interlayer friction between a rigid flake and a spring-supported hydrogenated graphene substrate by molecular dynamics simulations. Our simulation results indicate that with the increase of the hydrogenation coverage, the atomic-level roughness of hydrogenated graphene is found to increase, which eventually results in the increasing friction. During the stretching process, the atomic-level roughness of hydrogenated graphene is gradually reduced, which can be used to interpret the mechanism of the reduction of friction induced by strain. Such strain-induced reductions are robust over a wide range of commensurability, loads, and sizes. Moreover, it is demonstrated that the superlow friction also can be realized through the formation of incommensurate interface, the low rigidity of substrate, and the extended size of flake in sliding direction. These findings provide not only a fundamental understanding for the evolution of friction on hydrogenated graphene, but also an important insight for improving the tribological behaviors of nanodevices based on functionalized graphene.
KeywordsFriction Hydrogenated graphene Biaxial strain Uniaxial strain Molecular dynamics
We acknowledge financial support of the National Natural Science Foundation of China (51405517, U1334208), the Natural Science Foundation of Hunan (2015JJ3155) and the Hunan Provincial Natural Science Foundation of China (2019JJ50622).
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