Atomically resolved interfacial water structures on crystalline hydrophilic and hydrophobic surfaces
Atomically resolved interfacial water structures on crystalline hydrophilic and hydrophobic surfaces
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DOI：
10.1039/d1nr00351h
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发表时间：
2021-03-14
期刊：
影响因子：
6.7
通讯作者：
Garcia, Ricardo
中科院分区：
文献类型：
--
作者：
Uhlig, Manuel R.;Benaglia, Simone;Garcia, Ricardo
水化层形成在浸入水中的亲水性结晶表面上。它们的存在也被预测为疏水表面，但实验证据是有争议的。使用3D-AFM成像，我们探测的疏水和亲水表面的界面水结构与原子尺度的空间分辨率。我们表明，结晶表面上的界面水的原子尺度结构呈现出两种对立的安排。在云母（一种常见的亲水性结晶表面）上，界面的特征在于形成2至3个水化层，水化层之间的距离约为0.3 nm。在疏水表面如石墨或六方氮化硼（h-BN）上，界面的特征在于形成间隔约0.5nm的2至4层。后一层间距表明水分子从表面附近排出并被烃分子取代。这在疏水表面和本体水之间产生了新的L5- 2nm厚的界面。分子动力学模拟再现了实验数据，证实了上述界面水结构。
Hydration layers are formed on hydrophilic crystalline surfaces immersed in water. Their existence has also been predicted for hydrophobic surfaces, yet the experimental evidence is controversial. Using 3D-AFM imaging, we probed the interfacial water structure of hydrophobic and hydrophilic surfaces with atomic-scale spatial resolution. We demonstrate that the atomic-scale structure of interfacial water on crystalline surfaces presents two antagonistic arrangements. On mica, a common hydrophilic crystalline surface, the interface is characterized by the formation of 2 to 3 hydration layers separated by approximately 0.3 nm. On hydrophobic surfaces such as graphite or hexagonal boron nitride (h-BN), the interface is characterized by the formation of 2 to 4 layers separated by about 0.5 nm. The latter interlayer distance indicates that water molecules are expelled from the vicinity of the surface and replaced by hydrocarbon molecules. This creates a new L5-2 nm thick interface between the hydrophobic surface and the bulk water. Molecular dynamics simulations reproduced the experimental data and confirmed the above interfacial water structures.