Molecular Dynamics Simulations of Water Condensation on Surfaces with Tunable Wettability
Molecular Dynamics Simulations of Water Condensation on Surfaces with Tunable Wettability
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DOI：
10.1021/acs.langmuir.0c00915
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发表时间：
2020-07-07
期刊：
影响因子：
3.9
通讯作者：
Nielsen, Steven O.
中科院分区：
文献类型：
--
作者：
Ranathunga, Dineli T. S.;Shamir, Alexandra;Nielsen, Steven O.
水冷凝在广泛的工业应用中起着重要作用。在过去的几年里，许多研究表明，在设计表面增强水的冷凝和去除性能的兴趣。众所周知，在冷凝过程中，异相成核作用优于均相成核作用。由于非均质成核起始于小尺度的表面上，因此非常需要在分子水平上表征水-表面相互作用。分子动力学（MD）模拟可以提供直接洞察异质成核和先进的表面设计。现有的MD模拟表面上的水凝结进行调整固体-水的货车德瓦尔斯相互作用能作为替代建模表面具有不同的润湿性。然而，这种方法不能反映表面和水分子之间的真实的分子间相互作用。在这里，我们报告的分子动力学模拟的水凝结在现实的表面上的烷乙醇胺自组装单分子膜与不同的头基化学。我们发现，降低表面疏水性显着增加水分子和表面之间的静电力，从而增加水的冷凝率。我们观察到我们的冷凝率结果与其他表面表征指标的结果之间存在很强的相关性，例如界面热导率，接触角和Garde及其同事的分子尺度润湿性指标。这项工作提供了深入了解在分子尺度上的水冷凝过程与可调润湿性的表面。
Water condensation plays a major role in a wide range of industrial applications. Over the past few years, many studies have shown interest in designing surfaces with enhanced water condensation and removal properties. It is well known that heterogeneous nucleation outperforms homogeneous nucleation in the condensation process. Because heterogeneous nucleation initiates on a surface at a small scale, it is highly desirable to characterize water-surface interactions at the molecular level. Molecular dynamics (MD) simulations can provide direct insight into heterogeneous nucleation and advance surface designs. Existing MD simulations of water condensation on surfaces were conducted by tuning the solid-water van der Waals interaction energy as a substitute for modeling surfaces with different wettabilities. However, this approach cannot reflect the real intermolecular interactions between the surface and water molecules. Here, we report MD simulations of water condensation on realistic surfaces of alkanethiol self-assembled monolayers with different head group chemistries. We show that decreasing surface hydrophobicity significantly increases the electrostatic forces between water molecules and the surface, thus increasing the water condensation rate. We observe a strong correlation between our rate of condensation results and the results from other surface characterization metrics, such as the interfacial thermal conductance, contact angle, and the molecular-scale wettability metric of Garde and co-workers. This work provides insight into the water condensation process at the molecular scale on surfaces with tunable wettability.