@article{XUE2024, 
author = {Dandan XUE and Zhi XU and Linyuan GUO and Wendi LUO and Liran MA and Yu TIAN and Ming MA and Qingdao ZENG and Ke DENG and Wenjing ZHANG and Yichun XIA and Shizhu WEN and Jianbin LUO},
title = {Low friction under ultrahigh contact pressure enabled by self-assembled fluorinated azobenzene layers},
year = {2024},
journal = {Friction},
volume = {12},
number = {7},
pages = {1434-1448},
keywords = {fluorination, ultrahigh contact pressure, self-assembled layer, robust lubrication},
url = {https://www.sciopen.com/article/10.1007/s40544-023-0782-2},
doi = {10.1007/s40544-023-0782-2},
abstract = {Extensive efforts have been made to pursue a low-friction state with promising applications in many fields, such as mechanical and biomedical engineering. Among which, the load capacity of the low-friction state has been considered to be crucial for industrial applications. Here, we report a low friction under ultrahigh contact pressure by building a novel self-assembled fluorinated azobenzene layer on an atomically smooth highly-oriented pyrolytic graphite (HOPG) surface. Sliding friction coefficients could be as low as 0.0005 or even lower under a contact pressure of up to 4 GPa. It demonstrates that the low friction under ultrahigh contact pressure is attributed to molecular fluorination. The fluorination leads to effective and robust lubrication between the tip and the self-assembled layer and enhances tighter rigidity which can reduce the stress concentration in the substrate, which was verified by density functional theory (DFT) and molecular dynamics (MD) simulation. This work provides a new approach to avoid the failure of ultralow friction coefficient under relatively high contact pressure, which has promising potential application value in the future.}
}