Abstract Friction on few-layer graphene supported by Si/SiOx and mica substrates was investigated using atomic force microscopy (AFM) and coordinated molecular dynamics (MD) simulations to examine friction hysteresis and wetting transparency. Experiments showed that graphene exhibited higher overall friction, as well as hysteresis, in high humidity conditions, while the hysteresis was not observed under dry conditions. Additionally, as samples were aged under ambient environmental conditions, the work of adhesion increased by an approximate factor of two, likely from oxidation of the surface or adsorption of oxygen containing species from the lab environment. When graphene was supported by mica substrates no significant friction hysteresis was observed. MD simulations showed similar influences to the friction forces with surface energy. Both experiments and simulations suggest that wetting transparency, or a small variation in surface energy resulting from varying the number of graphene layers, contributes to the layer dependent friction forces measured on graphene.

中文翻译：

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通过纳米级摩擦评估原始和老化石墨烯的润湿透明度和表面能

摘要 使用原子力显微镜 (AFM) 和协调分子动力学 (MD) 模拟研究了由 Si/SiOx 和云母衬底支撑的几层石墨烯的摩擦，以检查摩擦滞后和润湿透明度。实验表明，石墨烯在高湿度条件下表现出更高的整体摩擦和滞后，而在干燥条件下未观察到滞后。此外，随着样品在周围环境条件下老化，粘附功增加了大约两倍，这可能是由于表面氧化或实验室环境中含氧物质的吸附。当石墨烯由云母基材支撑时，没有观察到明显的摩擦滞后。MD 模拟显示了对摩擦力与表面能的相似影响。