微结构表面 Cassie/Wenzel 润湿模式转换机制研究

摘要

Wenzel and Cassie models are two main kinds of solid-liquid wetting models on the rough surfaces.Cassie wetting model is helpful to super-hydrophobic and self-clean function of micro-structure surfaces,so that it is a must for su-per-hydrophobic surfaces to prevent solid-liquid interface transiting from Cassie model to Wenzel model.The transition mechanism of Cassie /Wenzel(C /W)wetting model and the condition to prevent C /W wetting model transition were re-searched.The results show that the size of surface energy is the decisive factor for wetting model transition.In order to pre-vent C /W wetting model transition,the suitable micro structural parameters are selected so that the Cassie model’s energy is under Wenzel model’s.For single grade micro structure surfaces of column /square concave and column /square convex, the C /W wetting model transition can be prevented by increasing the concave depth and convex height or reducing the spacing of concave and convex.The concave micro-structures are helpful to prevent C /W wetting model transition and even more suitable to prepare super-hydrophobic surfaces.%粗糙表面固液润湿模式主要有 Wenzel、Cassie 2种，Cassie 润湿模式有利于微结构表面的超疏水自清洁作用，因而对于超疏水表面需要阻止固液界面从 Cassie 模式向 Wenzel 模式转换。探讨 Cassie /Wenzel （C /W）润湿模式转换机制以及微结构表面阻止 C /W润湿模式转换的条件。研究表明，表面能大小是导致润湿模式转换的决定性要素，要阻止 C /W润湿模式转换，应当选择适当的表面微结构几何参数使得 Cassie 模式的能量比 Wenzel 模式的低；对于圆柱/方状凹坑、圆柱/方状凸起等单级微观结构表面，可以通过增大凹坑深度比/凸起高度比或者减小凹坑/凸起间距比阻止发生 C /W润湿模式转换。而凹坑微观结构有利于防止 C /W润湿模式转换，更适合制备超疏水表面。