Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai, 201800, China.
J Chem Phys. 2012 Jul 14;137(2):024703. doi: 10.1063/1.4733719.
The dewetting transitions of two hydrophobic plates immersed in pure water, aqueous ethanol solutions with concentrations from 25% to 90%, and pure ethanol were investigated by molecular dynamics simulations, where the dewetting transition was analogous to a first-order phase transition from liquid to vapor. It was found that the dewetting transitions occurred except that in the pure ethanol system. Although the ethanol molecules prefer to locate in the vicinity of the two plates, the inter-plate region is unfavorable for water molecules, due to losing more than one hydrogen bond. Moreover, each inter-plate water molecule forms hydrogen bonds on average with about two ethanol molecules. These intermolecular hydrogen bonds cause water and ethanol to cooperatively fill or exit the inter-plate region. Thus, water molecules play a more important role in the inter-plate filling/empty process, and induce the ethanol dewetting transition. Our results provide insight into the effect of water on the ethanol dewetting phenomena.
通过分子动力学模拟研究了两块浸入纯水中、浓度从 25%到 90%的水-乙醇溶液以及纯乙醇中的疏油板的去湿转变，其中去湿转变类似于从液相到气相的一级相变。结果发现，除了在纯乙醇体系中外，都发生了去湿转变。尽管乙醇分子倾向于位于两块板的附近，但由于失去了一个以上的氢键，两板之间的区域不利于水分子存在。此外，每个两板之间的水分子平均与大约两个乙醇分子形成氢键。这些分子间氢键导致水和乙醇协同地填充或离开两板之间的区域。因此，水分子在两板之间的填充/排空过程中起着更重要的作用，并导致乙醇的去湿转变。我们的结果提供了对水对乙醇去湿现象的影响的深入了解。
