College of Polymer Science and Engineering, State Key Laboratory of Polymer Material and Engineering , Sichuan University , Chengdu 610065 , People's Republic of China.
ACS Appl Mater Interfaces. 2018 Aug 29;10(34):28828-28838. doi: 10.1021/acsami.8b07635. Epub 2018 Aug 15.
The poor dispersibility, strong interlayer interaction, and inferior crack resistance ability restrict the employment of graphene as a lubricant additive. Herein, we prepared fluorinated graphene with different F/C ratios by direct fluorination of multilayer graphene utilizing F. Among them, highly fluorinated graphene (HFG) with an F/C ratio of about 1.0 presented prominent thermal stability and excellent tribological performance as an oil-based lubricant additive, whose friction coefficient and wear rate had a 51.4 and 90.9% decrease compared to that of pristine graphene, respectively. It was confirmed that C-F bonds perpendicular to the graphene plane contributed to increasing the interlayer distance and tribological performance of fluorinated graphene, while the randomly oriented CF and CF groups did not count as influential, as demonstrated via X-ray diffraction, X-ray photoelectron spectroscopy, and polarized attenuated total reflection-Fourier transform infrared spectroscopy. Meanwhile, Raman measurements traced the formation process of integrated and stable HFG tribofilm during friction process, and the corresponding stability was attributed to the physical and chemical interactions between HFG and friction pairs. More interestingly, the outstanding crack resistance ability of HFG preserved the sheet structure from destruction due to decreased in-plane stiffness and out-plane stress, thus constructing the tough tribofilm. The simple and feasible preparation makes HFG a promising candidate as advanced lubricant in industrial fabrication.
石墨烯作为一种润滑剂添加剂，其较差的分散性、较强的层间相互作用和较差的抗裂能力限制了其应用。在此，我们通过利用 F 原子直接氟化多层石墨烯，制备了不同 F/C 比的氟化石墨烯。其中，F/C 比约为 1.0 的高度氟化石墨烯（HFG）作为一种油基润滑剂添加剂表现出突出的热稳定性和优异的摩擦学性能，其摩擦系数和磨损率分别比原始石墨烯降低了 51.4%和 90.9%。X 射线衍射、X 射线光电子能谱和偏振衰减全反射-傅里叶变换红外光谱证实，垂直于石墨烯平面的 C-F 键有助于增加氟化石墨烯的层间距和摩擦学性能，而无规取向的 CF 和 CF2 基团则没有影响。同时，拉曼测量跟踪了摩擦过程中整合和稳定的 HFG 摩擦膜的形成过程，其相应的稳定性归因于 HFG 与摩擦副之间的物理和化学相互作用。更有趣的是，HFG 的出色抗裂能力使片层结构得以保留，从而防止了由于面内刚度和面外应力的降低而导致的破坏，从而构建了坚韧的摩擦膜。这种简单可行的制备方法使 HFG 成为工业制造中先进润滑剂的有前途的候选材料。
