Water at a hydrophilic solid surface probed by ab initio molecular dynamics: Inhomogeneous thin layers of dense fluid
Water at a hydrophilic solid surface probed by ab initio molecular dynamics: Inhomogeneous thin layers of dense fluid
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DOI：
10.1021/ja042963u
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发表时间：
2005-05-11
影响因子：
15
通讯作者：
Galli, G
中科院分区：
文献类型：
--
作者：
Cicero, G;Grossman, JC;Galli, G
我们提出了从头算分子动力学模拟获得的液态水和亲水固体表面之间界面的微观模型。我们特别关注立方碳化硅的 (100) 表面，立方碳化硅是生物相容性设备的领先半导体候选材料。我们的结果表明，在与清洁基材接触的液体中，分子解离的发生方式与气相中观察到的方式出乎意料地相似。完全羟基化发生后，观察到形成薄层（类似于 3 A）界面层，其密度高于本体水，并与基材形成稳定的氢键。这种薄层的存在表明，类似 1.3 nm 亲水基质之间的一维限制对水的结构特性的影响相当弱。此外，我们的结果表明，液体并不均匀地润湿表面，但分子优选沿着平行于 Si climer 行的方向结合。
We present a microscopic model of the interface between liquid water and a hydrophilic, solid surface, as obtained from ab initio molecular dynamics simulations. In particular, we focused on the (100) surface of cubic SiC, a leading semiconductor candidate for biocompatible devices. Our results show that in the liquid in contact with the clean substrate, molecular dissociation occurs in a manner unexpectedly similar to that observed in the gas phase. After full hydroxylation takes place, the formation of a thin (similar to 3 A) interfacial layer is observed, which has higher density than bulk water and forms stable hydrogen bonds with the substrate. The presence of this thin layer points at rather weak effects on the structural properties of water induced by a one-dimensional confinement between similar to 1.3 nm hydrophilic substrates. In addition, our results show that the liquid does not uniformly wet the surface, but molecules preferably bind along directions parallel to the Si climer rows.