Dipartimento di Ingegneria Meccanica e Aerospaziale, Università di Roma La Sapienza, Via Eudossiana 18, 00184 Roma, Italy.
Langmuir. 2012 Jul 24;28(29):10764-72. doi: 10.1021/la3018453. Epub 2012 Jul 10.
In this work, we study the wetting of a surface decorated with one nanogroove by a bulk Lennard-Jones liquid at various temperatures and densities. We used atomistic simulations aimed at computing the free energy of the stable and metastable states of the system, as well as the intermediate states separating them. We found that the usual description in terms of Cassie-Baxter and Wenzel states is insufficient, as the system presents two states of the Cassie-Baxter type. These states are characterized by different curvatures of the meniscus. The measured free energy barrier separating the Cassie-Baxter from the Wenzel state (and vice versa) largely exceeds the thermal energy, attesting the existence of Cassie-Baxter/Wenzel metastabilities. Finally, we found that the Cassie-Baxter/Wenzel transition follows an asymmetric path, with the formation of a liquid finger on one side of the groove and a vapor bubble on the opposite side.
在这项工作中，我们研究了在不同温度和密度下，由大块 Lennard-Jones 液体润湿带有一个纳米槽的表面。我们使用原子模拟的方法来计算系统的稳定和亚稳状态的自由能，以及分隔它们的中间状态。我们发现，通常用 Cassie-Baxter 和 Wenzel 状态来描述是不够的，因为系统呈现出两种 Cassie-Baxter 类型的状态。这些状态的特点是弯月面的曲率不同。从 Cassie-Baxter 到 Wenzel 状态（反之亦然）的测量自由能势垒大大超过热能，证明了 Cassie-Baxter/Wenzel 亚稳性的存在。最后，我们发现 Cassie-Baxter/Wenzel 转变遵循不对称路径，在槽的一侧形成一个液体指，而在另一侧形成一个蒸汽泡。
