Abstract In this study, the wetting states and wetting transition of droplets on the microstructured surfaces are investigated using the multiphase lattice Boltzmann method. The Cassie-Baxter (Cassie) and Wenzel wetting states on the rough surfaces are captured through the simulations, and the stability of Cassie state and the wetting transition are then studied and discussed by simulating the evaporation of droplets on several specified microstructured surfaces. The simulated apparent contact angles of the droplet on various rough surfaces fit the theoretical predictions very well. The results also present the coexistence of the Wenzel and Cassie states when the substrate is moderately hydrophobic with its Young’s angle smaller than the critical angle. In addition, the “De-pinning” wetting transition from Cassie to Wenzel state is observed for the moderately hydrophobic substrate once the droplet reduces to its critical radius, while the stable Cassie state is obtained when the substrate’s Young’s angle larger than the critical angle. The simulated critical radii for wetting transition are in quantitative agreements with the analytical values for different surface geometries and Young’s angles. This work provides mesoscopic information necessary for understanding the wetting phenomena on microstructured rough surfaces.

中文翻译：

---

使用晶格玻尔兹曼模型研究微结构表面上液滴的润湿状态和润湿转变

摘要 在这项研究中，使用多相晶格玻尔兹曼方法研究了微结构表面上液滴的润湿状态和润湿转变。通过模拟捕获了粗糙表面上的 Cassie-Baxter (Cassie) 和 Wenzel 润湿状态，然后通过模拟几个特定微结构表面上液滴的蒸发来研究和讨论 Cassie 状态的稳定性和润湿转变。液滴在各种粗糙表面上的模拟表观接触角非常符合理论预测。结果还表明，当基底具有中等疏水性且杨氏角小于临界角时，Wenzel 和 Cassie 态共存。此外，一旦液滴减小到其临界半径，中等疏水性基材就会观察到从 Cassie 到 Wenzel 状态的“脱钉”润湿转变，而当基材的杨氏角大于临界角时，获得稳定的 Cassie 状态。润湿过渡的模拟临界半径与不同表面几何形状和杨氏角的分析值定量一致。这项工作提供了理解微结构粗糙表面上的润湿现象所必需的细观信息。润湿过渡的模拟临界半径与不同表面几何形状和杨氏角的分析值定量一致。这项工作为理解微结构粗糙表面上的润湿现象提供了必要的细观信息。润湿过渡的模拟临界半径与不同表面几何形状和杨氏角的分析值定量一致。这项工作为理解微结构粗糙表面上的润湿现象提供了必要的细观信息。