聚合物刷界面的水润滑机理及宏观摩擦力调控行为研究

Inspired by the natural synovial joint microstructure and lubrication mechanism, the scientists found that an ultra-low coefficient of friction has been obtained between the rubbing surface grafted polymer brush even at the relatively slow speed, and is almost not dependent of the sliding speed. Much research work has been intensively carried out to investigate this super lubricity mechanism of polymer brush in the field of physical chemistry, in recent years relative research work under practical, engineering condition has aroused great concern of scientists. This proposal would study the macro tribological performance and lubrication mechanism lubricated by water by designing robust polymer brushes between rubbing surface as following: 1)to investigate the friction and wear properties of polymer brushes using a nano-friction tester; 2)to reveal lubrication performance polymer brush by means of thin film thickness test rig by interferometry; 3)to first time in situ measure the lubricant viscosity between the polymer brush interface based on laser induced fluorescence technology and then discuss the rheological properties;4)to build thin film lubrication model between polymer brush interface. We would like to clarify which parameter may have some or important influence on tribological performance, to probe the lubrication mechanism and then to possibly tune interface friction based on the above results. It is believed that this project would help to understand the natural joint lubrication mechanism and the friction mechanism under water lubrication under practical, engineering condition, which has much theoretical and practical significance for solving the lubrication problem of artificial joint and for great potential industrial application.

受天然滑液关节微观结构和润滑机制的启发，研究者发现水润滑的表面接枝聚合物刷界面即使在相对较慢的摩擦速度下仍获得超低的摩擦系数，且几乎不依赖于速度，然而聚合物刷这种超润滑机理的研究主要集中在物理化学领域，近年来接近实际工程条件下的研究引起了学者们极大关注。本项目提出在相互摩擦的表面接枝聚合物刷，对水润滑下聚合物刷引起的宏观摩擦性能和润滑机理进行研究：1)通过摩擦磨损实验机研究聚合物刷的摩擦和磨损性能；2)利用光干涉薄膜测量仪研究聚合物刷的润滑性能；3)首次提出利用激光诱导荧光测量法原位测量聚合物刷界面间润滑剂的粘度，研究高剪切率下的流变特性；4)尝试建立聚合物刷界面薄膜润滑的数学模型。基于以上研究明确聚合物刷界面水润滑的影响因素，揭示其润滑机理，实现界面摩擦力调控。本项目的开展将有助于深入理解天然关节润滑机理和水润滑下的摩擦机制，对解决人工关节的润滑问题和潜在的工业应用价值具有理论和现实意义

受天然滑液关节微观结构和润滑机制的启发，研究者发现水润滑的表面接枝聚合物刷界面即使在相对较慢的摩擦速度下仍获得超低的摩擦系数，且几乎不依赖于速度，然而聚合物刷这种超润滑机理的研究主要集中在物理化学领域，近年来接近实际工程条件下的研究引起了学者们极大关注。本项目提出在相互摩擦的表面接枝聚合物刷，对水润滑下聚合物刷引起的宏观摩擦性能和润滑机理进行研究：1)突破表面制备技术的壁垒，成功在玻璃盘(大尺寸)和陶瓷球(球面)的表面成功接枝了5种不同的聚合物刷；2) 证实了表面接枝聚合物刷可有效降低摩擦磨损，发现不同接枝原理制备的聚合物刷的摩擦机制是不同，例如graft to型和graft from型，前者的抗磨减摩机理源于摩擦运动过程中聚合物刷的自治愈行为，后者则是聚合物刷在接触表面形成了一层极薄的水合层；3)利用光干涉测量技术将聚合物刷形成水合层的过程进行了光学验证，光干涉的测量结果印证了水合效应是聚合物刷获得优异润滑性能的关键所在，并通过表面改性改变聚合物刷水合效应的方法实现了界面摩擦力和膜厚的调控；4)发现了聚合物刷在流体动压效应和水合效应共同作用可获得令人惊喜的润滑增强效应，分析其原因与聚合物刷降低了接触区表面的弹性模量或引起入口区粘度增大有关；5)对比研究了硬-硬和软-硬接触下的成膜机理，发现后者发生的表面变形有助于获得良好的润滑性能，并提出了更为合理的理论模型来预测膜厚；6)研发了一台能更好地模拟人体生理环境的球-窝式仿生人工关节薄膜测量装置，可实现研究基本日常活动下关节滑液的成膜。基于以上研究明确聚合物刷界面水润滑的影响因素，揭示其润滑机理，实现界面摩擦力调控。本项目的开展将有助于深入理解天然关节润滑机理和水润滑下的摩擦机制，对解决人工关节的润滑问题和潜在的工业应用价值具有理论和现实意义。