School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST) , Wuhan 430074, China.
Langmuir. 2017 Oct 31;33(43):12379-12388. doi: 10.1021/acs.langmuir.7b03193. Epub 2017 Oct 18.
Recently, numerous studies focused on the wetting process of droplets on various surfaces at a microscale level. However, there are a limited number of studies about the mechanism of condensation on patterned surfaces. The present study performed the dynamic wetting behavior of water droplets and condensation process of water molecules on substrates with different pillar structure parameters, through molecular dynamic simulation. The dynamic wetting results indicated that droplets exhibit Cassie state, PW state, and Wenzel state successively on textured surfaces with decreasing solid fraction. The droplets possess a higher static contact angle and a smaller spreading exponent on textured surfaces than those on smooth surfaces. The condensation processes, including the formation, growth, and coalescence of a nanodroplet, are simulated and quantitatively recorded, which are difficult to be observed by experiments. In addition, a wetting transition and a dewetting transition were observed and analyzed in condensation on textured surfaces. Combining these simulation results with previous theoretical and experimental studies will guide us to understand the hypostasis and mechanism of the condensation more clearly.
最近，许多研究都集中在微尺度下液滴在各种表面上的润湿过程上。然而，关于图案化表面上的冷凝机制的研究却很少。本研究通过分子动力学模拟，研究了具有不同支柱结构参数的基底上水 滴的动态润湿行为和水分子的冷凝过程。动态润湿结果表明，液滴在具有递减固体分数的织构表面上依次呈现 Cassie 状态、PW 状态和 Wenzel 状态。与光滑表面相比，在织构表面上的液滴具有更高的静态接触角和更小的扩展指数。模拟并定量记录了包括纳米液滴的形成、生长和聚结在内的冷凝过程，这是实验难以观察到的。此外，在织构表面上的冷凝过程中观察到了润湿转变和去润湿转变，并对其进行了分析。将这些模拟结果与以前的理论和实验研究相结合，将有助于我们更清楚地理解冷凝的本质和机制。
