Dorrer Christian, Rühe Jürgen
University of Freiburg, Department of Microsystems Engineering, Laboratory for the Chemistry and Physics of Interfaces, Georges-Köhler-Allee 103, D-79110 Freiburg, Germany.
Langmuir. 2007 Mar 27;23(7):3820-4. doi: 10.1021/la063130f. Epub 2007 Feb 21.
On rough surfaces, two distinct wetting modes can appear. These two states are usually described by the theories of Cassie (drops suspended on top of roughness features) and Wenzel (drops impaled on roughness features). Whereas the wetting transition from the Cassie to the Wenzel state has been relatively well studied both experimentally and theoretically, the question of whether metastable Wenzel drops exist and how they transition to the Cassie state has remained open. In this work, we study the wetting behavior of microstructured post surfaces coated with a hydrophobic fluoropolymer. Through condensation, the formation of metastable Wenzel droplets is induced. We show that under certain conditions drops can transition from the Wenzel to the Cassie state.
在粗糙表面上，会出现两种不同的润湿模式。这两种状态通常由卡西理论（液滴悬浮在粗糙度特征之上）和温泽尔理论（液滴刺入粗糙度特征）来描述。虽然从卡西状态到温泽尔状态的润湿转变在实验和理论上都得到了相对充分的研究，但亚稳态温泽尔液滴是否存在以及它们如何转变为卡西状态的问题仍然悬而未决。在这项工作中，我们研究了涂有疏水性含氟聚合物的微结构柱面的润湿行为。通过冷凝，诱导形成了亚稳态温泽尔液滴。我们表明，在某些条件下，液滴可以从温泽尔状态转变为卡西状态。
