硅基底复合自组装膜的制备及其微摩擦磨损性能研究

采用共吸附法，在硅基底表面制备3-氨基丙基三乙氧基硅烷(APS)和十二烷基三甲氧基硅烷(WD-10)复合自组装膜. 通过分子动力学模拟不同温度与混合分子在不同比例下的混合体系界面结合能；依据模拟结果，采用正交试验法设计试验方案制备9种不同条件下的自组装膜；采用原子力显微镜、接触角测定仪以及X射线光电子能谱仪对自组装膜的表面形貌、湿润性能和化学成分进行表征分析；利用微摩擦测试仪对自组装膜的微摩擦磨损性能进行性能测试. 结果表明:混合分子成功组装到羟基化硅基底表面，并且当组装温度为25 ℃，组装时间为4 h，组装溶液的pH为6时，自组装膜的质量较好；制备的复合自组装膜由于引起了边界润滑效应，有效减小了试件表面的摩擦磨损，且两种混合分子比例为1:1时自组装膜的减摩特性最佳. 

Preparation and Microtribological Properties of Self-assembling Composite Films on Silicon Substrate

Self-assembling composite monolayers of 3-aminopropyl triethoxysilane (APS) and dodecyl trimethoxysilane (WD-10) were coated on the surface of silicon substrate by coadsorption method. Molecular dynamics was used to simulate the interfacial binding energy of the mixed system at elevated temperatures and under different molecule ratios. And nine different experimental conditions were designed by orthogonal design according to the simulation results. The surface morphologies, wettability and chemical composition of SAMs were characterized by atomic force microscopy, contact angle tester and X-ray photoelectron spectroscopy, the results showed that silane molecules were successfully fabricated on the surface of the hydroxylated silicon substrate and the best quality of the SAMs was obtained at 25 ℃ for assembly temperature, 4 h for assembly time and 6 for the pH of the solution. Besides, the microtribological properties of SAMs were evaluated on a microtribometer and the worn surface were investigated by scanning electron microscope. Compared with the hydroxylated substrate, the SAMs caused boundary lubrication effect and reduced the friction and wear on the surface of the specimens. And the lowest friction coefficient and smallest width of wear were achieved at 1:1 for the ratio of APS to WD-10.