Nanotribological characterization of graphene on soft elastic substrate

Graphene is one of the key building blocks for a broad range of flexible/stretchable electronics and has great potential as a solid lubricant in flexible micro/nanoelectromechanical systems, soft robot and microfluidic devices due to their excellent electrical, mechanical and tribological properties. The nanotribological properties of graphene on soft elastic substrate were studied using the calibrated atomic force microscopy (AFM). The nanotribological properties of graphene on soft elastic substrate were enhanced by the elastic deformation compared with the hard SiO2/Si substrate. Also the friction force of graphene on soft elastic substrate decreases with the increase of the thickness and shows a sub-linear dependence on the indentation depth. A novel model of the elastic deformation enhancing puckering effect was proposed to explain the nanotribological properties of graphene on soft elastic substrate. The atomic-scale frictional behaviors of graphene on soft elastic substrate confirmed the mechanism of the elastic deformation enhanced puckering effect. These studies can provide a fundamental understanding of graphene as a solid lubricant on soft elastic substrate for graphene-based flexible MEMS/NEMS devices.

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