Effect of Surface Hydrophilicity on the Interfacial Properties of a Model Octane–Water–Silica System
Effect of Surface Hydrophilicity on the Interfacial Properties of a Model Octane–Water–Silica System
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表面亲水性对辛烷-水-二氧化硅模型体系界面性质的影响
DOI：
10.1021/acs.jpcc.9b04970
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Errington, Jeffrey R.
中科院分区：
文献类型：
--
作者：
Guo, Wenjing;Errington, Jeffrey R.
我们使用分子模拟来研究底物亲水性对羟基化β-方石英（111）表面的水在母体辛烷液体中的润湿特性的影响。我们采用了由Lee和Rossky [Lee， S. H.；罗斯基，p.j.j.化学。Phys.1994, 100, 3334 - 3345]。衬底的亲水性通过缩放放置在二氧化硅衬底第一层内原子上的部分电荷的大小来调节（衬底极性的修改）。在300和400k的温度下，用界面电位法计算了大范围亲水性下水滴在衬底上的接触角。我们的结果说明了水接触角的异常趋势。对于相对疏水的表面，系统的行为与预期的一样，基材极性的增加导致接触角的减少。然而，在足够高的衬底极性下，接触角的值达到最小，极性的进一步增加导致接触角的增加。界面上吸附的水量在极值点附近突然变化。从宏观角度看，液滴周围有一层单层厚的前驱体膜，具有足够高的衬底极性。我们将这些宏观性质的演变与水在β-方石石（111）表面的组织方式联系起来。通过分析构型快照、密度分布、面内径向分布函数和分子取向概率分布来表征该结构。分析表明，水分子存在于β-方石英（111）表面的空心中，具有足够高的底物极性。随着极性的增加，界面水分子逐渐采用更平面的结构，并限制了它们在随后的界面层中与水形成的氢键的数量。这种界面水结构的演化导致了水-基质相互作用的有效减弱和相应的水接触角的增大。
We use molecular simulation to study the impact of substrate hydrophilicity on the wetting properties of water at a hydroxylated β-cristobalite (111) surface in a mothern-octane liquid. We employ the silica model introduced by Lee and Rossky [Lee, S. H.; Rossky, P. J.J. Chem. Phys.1994,100, 3334–3345]. The hydrophilicity of the substrate is tuned by scaling the magnitude of partial charges placed on atoms within the first layer of the silica substrate (modification of the substrate polarity). An interface potential approach is used to compute the contact angle of a water droplet at the substrate over a wide range of hydrophilicities at temperatures of 300 and 400 K. Our results illustrate an anomalous trend in the contact angle of water. For relatively hydrophobic surfaces, the system behaves as is expected, with increases in substrate polarity resulting in a decrease in the contact angle. However, at a sufficiently high substrate polarity, the value of the contact angle reaches a minimum, with further increases in polarity leading to an increase in the contact angle. The amount of water adsorbed at the interface changes abruptly in the vicinity of the extremum point. From a macroscopic perspective, a monolayer-thick precursor film surrounds the droplet at sufficiently high substrate polarity. We link the evolution of these macroscopic properties to the manner in which water organizes at the β-cristobalite (111) surface. The structure is characterized via analysis of configurational snapshots, density profiles, in-plane radial distribution functions, and molecular orientation probability distributions. The analysis reveals that water molecules reside within the hollows of the β-cristobalite (111) surface at sufficiently high substrate polarity. As the polarity increases, the interfacial water molecules progressively adopt a more planar structure and limit the number of hydrogen bonds that they form with water in subsequent interfacial layers. This evolution of the interfacial water structure leads to an effective weakening of the water–substrate interaction and corresponding increase in the water contact angle.
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DOI：
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发表时间：
2008
期刊：
影响因子：
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界面势的计算机模拟：走向复杂界面的第一原理描述？
DOI：
--
发表时间：
2011
期刊：
影响因子：
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作者：
L. G. Macdowell
通讯作者：
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