Water interaction with dielectric surface: A combined ab initio modeling and experimental study
Water interaction with dielectric surface: A combined ab initio modeling and experimental study
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DOI：
10.1063/5.0046587
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发表时间：
2021-04
影响因子：
4.6
通讯作者：
Vitaliy Yurkiv;Jingwei Wu;Subhayan Halder;R. Granda;A. Sankaran;A. Yarin;F. Mashayek
中科院分区：
文献类型：
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作者：
Vitaliy Yurkiv;Jingwei Wu;Subhayan Halder;R. Granda;A. Sankaran;A. Yarin;F. Mashayek
结合从头计算模型和实验研究水吸附在干燥的疏水介质表面。这是在各种技术应用中用于受控液滴沉积的重要现象。从头算密度泛函理论计算进行揭示占主导地位的水吸附位点，能量，和电子密度分布的聚四氟乙烯和parafilm表面。几种表面状态，如拉伸，无缺陷，有缺陷的被认为是水吸附研究。结果表明，拉伸的无缺陷的表面导致较弱的水吸附相比，未拉伸的表面。因此，这种拉伸使得表面更加疏水，如电子密度分布所揭示的。特氟龙和parafilm表面的随机缺陷的引入导致水吸附能的增加，在某些情况下，几乎亲水相互作用。这些研究结果是在良好的协议与目前的测量静态接触角的预拉伸聚四氟乙烯和parafilm样品，拉伸不仅拉长原子间的键，但也改变了表面粗糙度。因此，目前结合的建模和实验研究允许背后的干燥疏水表面的润湿性的变化的原因的机械解释。
A combined ab initio modeling and experimental study of water adsorption on a dry hydrophobic dielectric surface is presented. This is an important phenomenon for controlled droplet deposition in various technological applications. The ab initio density functional theory calculations are performed to reveal the dominant water adsorption sites, energetics, and the electron density profile on Teflon and parafilm surfaces. Several surface states such as stretched, nondefective, and defective are considered for water adsorption studies. It is revealed that stretching of nondefective surface leads to weaker water adsorption compared to an unstretched surface. Accordingly, such stretching makes the surface more hydrophobic as revealed by the electron density profile. The introduction of random defects into Teflon and parafilm surfaces results in an increase in water adsorption energy leading, in some cases, to practically hydrophilic interactions. These findings are in good agreement with the present measurements of static contact angle on prestretched Teflon and parafilm samples, where stretching not only elongates interatomic bonds but also changes the surface roughness. Thus, the present combined modeling and experimental study allows for a mechanistic interpretation of the reasons behind the change of wettability of dry hydrophobic surfaces.