Liu Xiaolong, Zheng Zhiwen, Xiang Juhua, Wang Hanwei, Wang Haizhong, Feng Dapeng, Qiao Dan, Li Hansheng
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
Langmuir. 2024 Dec 31;40(52):27364-27376. doi: 10.1021/acs.langmuir.4c03592. Epub 2024 Dec 19.
Three α-alkene lubricants, differentiated by chain length, were selected as model compounds to investigate the influence of chain length on tribological properties. The novelty of this study lies in setting chain length as the sole variable to explore its impact on surface and adsorption energy. Based on the above findings, the study provides a unique explanation of the intrinsic relationship between chain length and tribological performance. The tribological properties of the three α-alkenes were compared, and subsequent characterization methods elucidated the wear mechanisms and explored tribochemical reactions. The study employed the Owens-Wendt-Rabel-Kaelble (OWRK) method and density functional theory (DFT) to investigate each compound's surface energy and adsorption energy. Experimental results revealed that the average friction coefficients (abridged as COF) for 1-decene, 1-tetradecene, and 1-octadecene decreased sequentially to 0.125, 0.099, and 0.075, respectively. The wear volume of 1-tetradecene decreased by 53.2% and that of 1-octadecene decreased by 64.0% compared to 1-decene. This can be attributed to the simultaneous enhancement of the surface energy and adsorption energy with increasing chain length. On the one hand, the increase in surface energy facilitates tribochemical reactions positively influencing the formation of tribofilms. On the other hand, the increase in adsorption energy enhances the adsorption of lubricants on the substrate surface. The synergy of these two effects allows 1-octadecene and 1-tetradecene (long-chain α-alkenes) to exhibit superior tribological performance compared to that of 1-decene (short-chain α-alkenes). Ultimately, this study offers unique insights into understanding lubrication mechanisms.
选择了三种通过链长区分的α-烯烃润滑剂作为模型化合物，以研究链长对摩擦学性能的影响。本研究的新颖之处在于将链长设为唯一变量，以探索其对表面能和吸附能的影响。基于上述发现，该研究对链长与摩擦学性能之间的内在关系给出了独特解释。比较了三种α-烯烃的摩擦学性能，随后的表征方法阐明了磨损机制并探索了摩擦化学反应。该研究采用欧文斯-温德特-拉贝尔-凯尔布尔（OWRK）方法和密度泛函理论（DFT）来研究每种化合物的表面能和吸附能。实验结果表明，1-癸烯、1-十四碳烯和1-十八碳烯的平均摩擦系数（简称为COF）依次降低至0.125、0.099和0.075。与1-癸烯相比，1-十四碳烯的磨损体积减少了53.2%，1-十八碳烯的磨损体积减少了64.0%。这可归因于随着链长增加表面能和吸附能同时增强。一方面，表面能的增加促进了对摩擦膜形成有积极影响的摩擦化学反应。另一方面，吸附能的增加增强了润滑剂在基底表面的吸附。这两种效应的协同作用使1-十八碳烯和1-十四碳烯（长链α-烯烃）相比1-癸烯（短链α-烯烃）表现出更优异的摩擦学性能。最终，本研究为理解润滑机制提供了独特见解。
