Jiang Yue, Lian Jianshe, Jiang Zhonghao, Li Yuncang, Wen Cuie
Key laboratory of Automobile Materials, College of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun 130025, China; School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia.
Key laboratory of Automobile Materials, College of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun 130025, China.
Adv Colloid Interface Sci. 2020 Apr;278:102136. doi: 10.1016/j.cis.2020.102136. Epub 2020 Mar 4.
Determining the equilibrium wetting states and exploring the conditions and mechanisms of the wetting state transition from the Cassie-Baxter (CB) state to the Wenzel (W) state (CB-W transition) have been a central topic in the study of superhydrophobic behavior on rough or textured surfaces. Although considerable progress has been made, some issues regarding this topic are still not completely understood. In this study, a systematic thermodynamic analysis has been performed to address several key issues related to this topic. Generalized theoretical expressions for determining the equilibrium wetting states (the threshold Young contact angle of the CB region) and evaluating the stability of the CB state (the energy barrier separating the CB and W states and the critical pressure for the CB-W transition) have been derived. Applying these expressions to four types of surfaces built with protrusions in paraboloid, truncated cone, inverted truncated cone and flat-top pillar shapes, the wetting equilibrium and resultant wetting states have been studied. The physical meanings of the threshold Young contact angle, the roles and mechanisms of the energy barrier and critical pressure in stabilizing the CB state have been discussed. Finally, a general guidance for achieving robust superhydrophobicity on the studied surfaces has been given.
确定平衡润湿状态并探索润湿状态从卡西 - 巴克斯特（CB）状态转变为文策尔（W）状态（CB - W转变）的条件和机制，一直是粗糙或有纹理表面超疏水行为研究的核心课题。尽管已取得了相当大的进展，但关于这一课题的一些问题仍未完全理解。在本研究中，进行了系统的热力学分析，以解决与该课题相关的几个关键问题。推导了用于确定平衡润湿状态（CB区域的阈值杨氏接触角）和评估CB状态稳定性（分隔CB和W状态的能垒以及CB - W转变的临界压力）的广义理论表达式。将这些表达式应用于由抛物面、截头圆锥、倒截头圆锥和平顶柱形状的凸起构建的四种类型表面，研究了润湿平衡和由此产生的润湿状态。讨论了阈值杨氏接触角的物理意义、能垒和临界压力在稳定CB状态中的作用和机制。最后，给出了在所研究表面上实现稳健超疏水性的一般指导。
