Liu Yangqin, Jiang Yilong, Sun Junhui, Wang Yang, Qian Linmao, Kim Seong H, Chen Lei
Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China.
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Nano Lett. 2022 Jul 27;22(14):6018-6025. doi: 10.1021/acs.nanolett.2c01043. Epub 2022 Jun 13.
Atomically thin two-dimensional (2D) materials are excellent candidates for utilization as a solid lubricant or additive at all length scales from macro-scale mechanical devices to micro/nano-electromechanical systems (MEMS/NEMS). In such applications, wear resistance of ultrathin 2D materials is critical for sustained lubrication performance. Here, we investigated the wear of fluorinated graphene (FG) nanosheets deposited on silicon surfaces using atomic force microscopy (AFM) and discovered that the wear resistance of FG improves as the FG thickness decreases from 4.2 to 0.8 nm (corresponding to seven layers to single layer) and the surface energy of the substrate underneath the FG nanosheets increases. On the basis of density function theory (DFT) calculations, the negative correlation of wear resistance to FG thickness and the positive correlation to substrate surface energy could be explained with the degree of interfacial charge transfer between FG and substrate which affects the strength of FG adhesion to the substrate.
从宏观机械设备到微纳机电系统（MEMS/NEMS），原子级薄的二维（2D）材料是在所有长度尺度上用作固体润滑剂或添加剂的极佳候选材料。在这类应用中，超薄二维材料的耐磨性对于持续的润滑性能至关重要。在此，我们使用原子力显微镜（AFM）研究了沉积在硅表面的氟化石墨烯（FG）纳米片的磨损情况，发现随着FG厚度从4.2纳米减小到0.8纳米（相当于从七层到单层）以及FG纳米片下方衬底的表面能增加，FG的耐磨性提高。基于密度泛函理论（DFT）计算，耐磨性与FG厚度的负相关以及与衬底表面能的正相关可以用FG与衬底之间的界面电荷转移程度来解释，这会影响FG与衬底之间的粘附强度。
