微织构和表面改性协同诱导硅基超疏水表面设计、制备及减摩抗磨机理研究

In the micro/nano electromechanical system, surface forces are much larger than body forces due to the scale effects, which becomes a key factor for the reliability and lifetime of the micro device. However, there are severe issues in regards to adhesion and wear on the micro/nano interfaces with extreme-gaps. To further understanding in this area, this proposal studies the design and preparation of superhydrophobic surface on the silicon (Si) substrate, as well as the mechanism of its antifriction and antiwear properties. Detailed research contents are as follows: by establishing the wetting model of a droplet on micro/nanoscale textured surface, the influence of the micro-texture feature parameters on the wetting state of droplets are analyzed, and the design principles to superhydrophobicity of Si substrate, which is induced by micro-texture are discussed; micro-texture arrays are prepared by etching technology and modified by compound molecular film of low surface energy, to demonstrate the synergistic effects of the micro-texture and compound molecular film on the superhydrophobicity by experiments; based on the tribology and contact adhesive theory, the microfluidic mode between the micro/nano surfaces with extreme-gaps is built, in addition to which, the contact mechanical model and tribology model of the micro-textured Si substrate modified with low-surface-energy compound molecular film are created, too; synergistic effects of the micro-texture and molecular film on anti-adhesion and antiwear performances are studied experimentally; the correlation model of “micro-texture feature parameters/molecular film properties – superhydrophobicity – friction” is gained, which provides theoretical basis for the application of the Si-based superhydrophobic surface with optimized friction property in the micro/nano electromechanical system.

在微/纳机电系统中，尺度效应使得表面力远大于体积力成为决定微器件可靠性和寿命的关键因素。针对极端间隙微/纳界面存在严重黏着和磨损的关键问题，本项目以单晶硅为基底进行超疏水表面设计、制备并探讨其减摩抗磨作用机理。建立微/纳复合表面织构润湿模型，探究微织构特征参数对液滴润湿状态的影响规律，提出微织构诱导硅基表面获得超疏水性能的设计准则；借助刻蚀技术加工有序微织构并修饰低表面能复合分子膜，实验揭示微织构与复合分子膜对超疏水性能的协同效应机理；结合摩擦学原理和接触黏着理论，建立极端间隙微/纳界面间微流体模型和低表面能改性后多尺度微织构硅基表面的接触力学模型和摩擦学模型；实验研究分子膜和微织构对减黏、减摩、抗磨性能的协同作用机理；得到“微织构特征参数/分子膜特性-超疏水性-摩擦特性”关系模型，为具有最优摩擦学特性的硅基超疏水表面在微/纳机电系统中的应用提供理论基础。

建立了跨尺度微/纳复合织构表面的润湿模型，揭示了微织构特征参数对表面润湿特性的影响规律，提出了微织构设计准则；采用感应耦合等离子体刻蚀技术，在单晶硅表面制备加工了微米级方柱阵列粗糙结构，结合双层复合自组装分子膜，得到了超疏水性能表面，采用湿法刻蚀，在方柱织构基底上，进一步设计并制备了腔形织构，极大的提高了超疏水性能的稳定性；采用分子动力学模拟方法，研究了复合分子膜的微观结构和组装过程，进一步揭示了纳米液滴在分子膜层表面的运动特性和润湿特性；采用接触角测量仪、傅里叶变换红外光谱仪和原子力显微镜对功能表面进行了润湿性能、分子组分、微观形貌和微尺度黏附行为的研究，结果表明超疏水性与减黏效应正相关；借助摩擦磨损试验机，考察了宏观摩擦学性能，结果表明制备的复合分子膜层有效的改善了单晶硅表面的减摩抗磨性能，为其应用于微机电系统, 降低微接触表面的黏着并提高耐磨性能提供了理论依据和试验基础.