在微纳尺度控制摩擦对于微纳机电系统的发展具有重要意义。以石墨烯为代表的二维材料通常包含若干原子层，而且具有与宏观固体润滑材料相媲美的优异润滑性能，有望成为微纳机电系统中的润滑材料。二维材料的摩擦性能通常会受到基底的作用，进而影响系统中的能量耗散机制，因此需要对基底影响二维材料表面摩擦行为的机制进行研究。本项目采用第一性原理计算为主结合Prandtl-Tomlinson(PT)模型计算和原子力显微镜实验的方法对基底上二维材料表面的摩擦行为进行研究，从电子尺度揭示二维材料表面摩擦的起源和本质；通过对二维材料和基底之间形成的moiré纹结构的研究，探索微纳尺度下调控二维材料表面摩擦特性的机制和化学改性条件下保持二维材料优异摩擦性能的机制。该项目的实施能够揭示基底影响二维材料表面摩擦行为的机制，为微纳尺度下二维材料作为润滑材料的应用提供理论和技术指导。

Control of friction at micro- and nano-scales is crucial and desirable for the developments of micro- and nano-electromechanical systems (MEMS/NEMS). The two dimensional (2D) materials, particular graphene, usually containing several layers with weak layer-to-layer coupling and owning the lubricity comparable to bulk lubricants, are the promising materials to be applied in MEMS/NEMS. However, the frictional properties are susceptible to the substrates beneath the 2D materials, which will influence the energy dissipation mechanism in the systems. Thus the mechanisms that the substrates affect the frictional behaviors of 2D materials should be investigated in depth. In this project, the first-principles calculations together with Prandtl-Tomlinson (PT) model calculations and atomic force microscope (AFM) experiments will be carried out to study the frictional behaviors of 2D material, revealing the origin of the friction on the 2D materials in electronic scale. Through the investigations of moiré superstructures formed between 2D materials and relevant substrates, try to explore the mechanisms of controlling the frictional properties of 2D materials at micro- and nano-scales and preserving the superior performance of 2D materials under chemical modification environment. The implementation of this project will reveal the mechanisms that the substrates influence the frictional behaviors of 2D materials, and provide with theoretical and technical guidance for the application of 2D materials as lubricating materials in MEMS/NEMS.