As the simplest model of transition between the superhydrophobic Cassie-Baxter (CB) and Wenzel (W) states of a macroscopic droplet sitting on a microscopically rough or corrugated substrate, a substrate whose surface is covered by identical truncated or inverted truncated conical pores is considered. The free-energy landscapes of the intrusion and extrusion processes of a liquid into single pore are analyzed when the liquid is compressed or stretched so that the liquid phase is either stable or metastable relative to the vapor phase. Therefore, this model is also relevant to the stability of the superhydrophobic submerged substrates. In this study, the macroscopic classical capillary theory is adopted. Even within this simplified model, two simple geometries of truncated and inverted truncated cones lead to completely different free-energy landscapes. A simple criterion for the stability of the CB state based on Laplace pressure is shown not to be sufficient to understand the destruction and recovery of the CB state. The free-energy landscapes indicate that a gradual and an abrupt destruction of CB state is possible, which depends on the orientation of the conical pore and whether the liquid is compressed or stretched. The extensions of these theoretical results to more complex geometries are briefly discussed.

中文翻译：

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截断和倒截头圆锥形孔中液体侵入和挤出的自由能态势：对Cassie-Baxter到Wenzel过渡的影响

作为位于微观粗糙或波纹状基材上的宏观液滴的超疏水Cassie-Baxter（CB）和Wenzel（W）状态之间过渡的最简单模型，考虑了其表面被相同的截短或倒置的圆锥形孔覆盖的基材。当液体被压缩或拉伸时，分析了液体进入和进入单孔的过程的自由能态势，以便液相相对于气相稳定或亚稳。因此，该模型也与超疏水性水下基质的稳定性有关。本研究采用宏观经典毛细管理论。即使在这种简化模型中，截头圆锥体和倒截头圆锥体的两个简单几何形状导致完全不同的自由能态势。基于拉普拉斯压力的CB状态稳定性的简单标准显示不足以理解CB状态的破坏和恢复。自由能态势表明可能会逐渐破坏CB状态，这取决于圆锥孔的方向以及液体是否被压缩或拉伸。简要讨论了这些理论结果到更复杂几何形状的扩展。这取决于圆锥孔的方向以及液体是否被压缩或拉伸。简要讨论了这些理论结果到更复杂几何形状的扩展。这取决于圆锥孔的方向以及液体是否被压缩或拉伸。简要讨论了这些理论结果到更复杂几何形状的扩展。