Li Jianfeng, Li Jinjin
State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China.
J Phys Chem Lett. 2022 Sep 8;13(35):8245-8253. doi: 10.1021/acs.jpclett.2c02144. Epub 2022 Aug 26.
Oxidized black phosphorus (BP) has been demonstrated as a promising oil-based nanoadditive because of its superior friction-reducing capability. However, the synergistic lubrication effect between oxidized BP and oil at the molecular level dominating the friction properties remains unclear. In this Letter, the synergistic lubrication effect between oxidized BP and two typical oil molecules (nonane and nonanoic acid) was explored with an atomic force microscope. The superlubricity of oxidized BP with an ultralow friction coefficient of 0.006 was achieved in the nonanoic acid environment, exhibiting a 96% reduction compared with that in the nonane environment. There was a confined nonanoic acid layer in the contact zone with a tilt angle of 35° because of the hydrogen bonding interaction, contributing to the superlubricity. This observation sheds light on the exploration of the lubrication mechanism of oxidized BP as a nanoadditive in oil, which reveals the considerable implications for the design of high-performance lubrication system.
氧化黑磷（BP）因其卓越的减摩能力已被证明是一种很有前景的油基纳米添加剂。然而，氧化BP与油在分子水平上主导摩擦性能的协同润滑效应仍不清楚。在这篇快报中，利用原子力显微镜探究了氧化BP与两种典型油分子（壬烷和壬酸）之间的协同润滑效应。在壬酸环境中实现了氧化BP的超润滑性，其超低摩擦系数为0.006，与在壬烷环境中的摩擦系数相比降低了96%。由于氢键相互作用，在接触区存在一个倾斜角为35°的受限壬酸层，这有助于实现超润滑性。这一观察结果为探索氧化BP作为油中纳米添加剂的润滑机制提供了线索，揭示了其对高性能润滑系统设计的重要意义。
