跨润滑状态的超低摩擦界面构筑与润滑机理研究

To design the lubrication system with ultralow friction has always been one of important research topics in the field of mechanical tribology, it is a very challenging research work to maintain ultralow friction coefficient even spanning different lubrication regime: from boundary lubrication to hydraulic lubrication. In this proposal, a multi-phase (solid-gas-liquid-solid) coupling lubrication system is proposed by designing a novel asymmetric interface wettability, in order to obtain the ultralow friction coefficient in wider bearing characteristic number range. Relative research work is as follows: 1) to set up the novel ultralow friction system based on superhydrophobic surface and hydrogel anchored superhydrophilic substrate; 2) to study the tribological properties in different lubrication regime mainly considering two key parameters - Hertz contact stress and the thickness of lubricating layer, and to clarify the lubrication mechanism using molecular dynamic simulation(MDS), and then to obtain the boundary lubrication condition when this multi-phase coupling lubrication system has failed; 3) to elucidate the transformation of lubrication mechanism, lubrication components and characteristic tribological parameters in different wetting states based on the above results, and possibly to realize a smart regulation of rubbing surface from boundary lubrication regime to hydraulic lubrication regime, while always keeping ultralow friction. It is believed that this project would provide a novel design scheme and essential support in terms of the technology for developing new lubrication system and for its near future application.

具有超低摩擦的润滑体系的设计一直是摩擦学学科中的重要研究课题，而如何在不同润滑状态仍然能够保持超低摩擦系数是一个极具挑战性的研究工作。本项目提出拟构筑一种新颖的固-气-液-固不对称特殊润湿界面多相复合的摩擦体系，在更宽的轴承特性数范围内实现超低摩擦，具体为：1）以超疏水表面和水凝胶修饰超亲水基底为基础，建立特殊润湿界面复合的不对称多相新型摩擦体系的构筑方法；2）以赫兹应力和润滑层厚度等为关键参数，进行不同润湿状态及润滑区域内体系摩擦学性能表征，通过分子动力学模拟明确超低摩擦机理，并获得此类特殊润湿界面复合的摩擦体系润滑失效的边界条件；3）阐明摩擦副表面化学组成和结构演变、润滑组分原位转移及摩擦学特性参数与体系不同界面润湿状态下润滑机理转变机制的关系规律，实现边界润滑到流体润滑的跨润滑状态超低摩擦界面的智能调控。本项目的研究为新型润滑体系的发展和应用提供了一种新的设计思路和技术支撑。

摩擦学理论和技术已被用于提高机械系统的工作效率，包括延长其使用寿命和减少事故的发生，甚至为解决能源短缺和环境问题提供有效策略。本项目在成功构建新型特殊浸润性界面多相复合摩擦体系的基础上，分别在Cassie状态和Wenzel状态下实现0.005和0.015的低摩擦系数，重点探索了不同摩擦学工况下多因素变量对多相复合界面润湿性转变、润滑机理及摩擦失效等核心问题的影响。进一步，在实现宽摩擦学工况及跨润湿状态新型摩擦体系构筑基础上，采用水和离子液体等绿色组分作为主要润滑剂，即使润滑剂在摩擦过程中挥发或泄露，也不会对环境造成污染，复合国家所倡导的创新发展要求。因此，本研究为设计绿色摩擦体系构建及实现超低摩擦原型提供了有益的参考。