疏油材料表面的润湿机理研究

The research and development of new oleophobic/superoleophobic materials are becoming an overarching concern in modern society. One of the constraints is a lack of understanding of wetting mechanism on material’s surfaces. And it is difficult to quantitatively describe the wettability of oleophobic polymer surfaces. Based on the topological structure of n-octane, a new theoretical model is built in this project by integrating three-dimensional polymer integral equation theory into three-dimensional density functional theory. By using this new theory, three-dimensional density profiles of n-octane on polymer surfaces can be accurately obtained. And the interfacial tension of n-octane can be calculated on micro rough surfaces. Meanwhile, the process of nucleation of n-octane on polymer surfaces can be studied. The energy barrier, critical nucleus radius and so on can be quantitatively calculated. Besides, the contact angle and line tension can be obtained. In addition, F-POSS nanoparticles are added into the polymer surfaces in order to research their effects on the wettability of material’s surfaces. According to a series of theoretical innovations, the effects of the chemical composition, roughness as well as surface modification on the wettability of material’s surface are analyzed comprehensively, and the wetting/dewetting mechanism can be interpreted at the nanoscale. After experimental verifications, a whole and rigorous theoretical method is formed, which can make a clear explanation of statistical mechanics on wettability of oil droplets on material’s surfaces.

新型疏油/超疏油材料的研制和开发正在成为人们关注的焦点，制约其发展的因素之一是对材料表面的疏油机理认识不足，定量描述疏油聚合物表面润湿性能成为难题。本项目基于正辛烷的空间拓扑结构，将三维聚合物积分方程理论引入到三维密度泛函理论中，建立新的密度泛函模型，使其能准确描述正辛烷在聚合物表面三维密度分布，进而计算正辛烷在微观粗糙表面的界面张力。同时，运用该理论模型研究正辛烷在聚合物材料表面的成核过程，定量计算成核能垒、临界成核半径等，并获得润湿角、线张力等物理量。此外，将低表面能的含氟POSS纳米颗粒添加到聚合物表面，研究其对材料表面润湿性能的影响。经理论创新，从纳米尺度上综合分析材料表面化学组成、粗糙度及表面修饰等因素对聚合物润湿性的影响，解释润湿/去润湿机理。经实验检验后，形成完整、严密的理论方法，为油滴在材料表面的疏油机理作出统计力学解释。

疏油/超疏油材料在国防、工农业生产和人们日常生活中有着广阔的应用前景。本项目利用密度泛函理论、积分方程理论等统计力学理论方法，将研究对象由简单模型体系（甲烷）拓展到实际复杂体系（链状烷烃）。基于实际流体的空间拓扑结构，结合新构建的理论模型，准确描述了实际流体在聚合物表面的三维密度分布，进而计算其在微观粗糙表面的界面张力。同时，运用该理论模型研究实际流体在聚合物材料表面以及纳米颗粒/聚合物复合表面的成核过程，定量计算成核能垒、临界成核半径等，并获得润湿角、线张力等物理量。由此，本项目可从纳米尺度上综合分析材料表面化学组成、粗糙度及表面修饰等因素对聚合物润湿性的影响。最终建立实际流体在不规则粗糙界面结构与表面润湿性能之间的内在联系，弄清疏油/超疏油表面功能材料的润湿机理，为新材料的设计与开发提供理论指导，同时，可以推动界面理论发展。