Deep eutectic solvents (DESs) have emerged as promising green liquid lubricants for solving tribological problems due to their economic and excellent physicochemical and lubrication properties. However, a trace amount of water would affect their structure, physicochemical properties, and tribological properties. The effect of water on the tribological properties of DES is still unclear and needs further investigate. Herein, we carried out a systematic investigation into the chemical structure, rheological properties, and tribological performance of DES-water (DES-W) binary systems constructed by combining DES with varying contents of water. The results revealed that low levels of water in DES had a minimal impact on its chemical structure but affected its fluidity and viscosity. Frictional experiments demonstrated that DES-W binary systems displayed a reduced coefficient of friction from 0.094 to 0.025 compared to pure DESs and manifested outstanding antiwear properties under a high-load condition. This was attributed to the formation of hydration layers, adsorption layers, and tribochemical films at the tribointerface through physicochemical adsorption and tribochemical reactions. Our findings not only foster the design and development of green lubricating materials but also expand the engineering applications of DESs to solve wear-related mechanical failures in practical application.

中文翻译：

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水对天然深共熔溶剂摩擦学性能的特殊影响


深共熔溶剂 （DES） 由于其经济和优异的物理化学和润滑性能，已成为解决摩擦学问题的有前途的绿色液体润滑剂。然而，微量的水会影响它们的结构、物理化学性质和摩擦学性质。水对 DES 摩擦学特性的影响尚不清楚，需要进一步研究。在此，我们对通过将 DES 与不同含量的水相结合构建的 DES-water （DES-W） 二元系统的化学结构、流变特性和摩擦学性能进行了系统研究。结果表明，DES 中低含量的水对其化学结构的影响最小，但会影响其流动性和粘度。摩擦实验表明，与纯 DES 相比，DES-W 二元系统的摩擦系数从 0.094 降低到 0.025，并且在高负载条件下表现出出色的抗磨损性能。这归因于通过物理化学吸附和摩擦化学反应在摩擦界面上形成水合层、吸附层和摩擦化学膜。我们的研究结果不仅促进了绿色润滑材料的设计和开发，还扩展了 DES 的工程应用，以解决实际应用中与磨损相关的机械故障。