High-resolution in situ x-ray study of the hydrophobic gap at the water-octadecyl-trichlorosilane interface
High-resolution in situ x-ray study of the hydrophobic gap at the water-octadecyl-trichlorosilane interface
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DOI：
10.1073/pnas.0608827103
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发表时间：
2006-12-05
影响因子：
11.1
通讯作者：
Honkimaki, Veijo
中科院分区：
文献类型：
--
作者：
Mezger, Markus;Reichert, Harald;Honkimaki, Veijo
了解界面处水的微观结构对于理解许多自然和技术环境中的界面现象至关重要。为了研究深埋的液态水-固体界面，进行了高能x射线反射率测量。由自组装单层十八烷基三氯硅烷功能化的硅片提供了强疏水性衬底。我们展示了与十八烷基三氯硅烷层接触的水的固液界面附近具有埃分辨率的界面密度剖面。实验数据为在分子尺度上存在疏水间隙提供了明确的证据，其在固水界面处的综合密度缺陷rho d = 1.1埃g cm（-3）。此外，还对溶解在水中的气体（Ar、Xe、Kr、N-2、O-2、CO和CO2）和HCl的影响进行了测量。对疏水间隙无影响。
The knowledge of the microscopic structure of water at interfaces is essential for the understanding of interfacial phenomena in numerous natural and technological environments. To study deeply buried liquid water-solid interfaces, high-energy x-ray reflectivity measurements have been performed. Silicon wafers, functionalized by a self-assembled monolayer of octadecyltrichlorosilane, provide strongly hydrophobic substrates. We show interfacial density profiles with angstrom resolution near the solid-liquid interface of water in contact with an octadecyltrichlorosilane layer. The experimental data provide clear evidence for the existence of a hydrophobic gap on the molecular scale with an integrated density deficit rho d = 1.1 angstrom g cm(-3) at the solid-water interface. In addition, measurements on the influence of gases (Ar, Xe, Kr, N-2, O-2, CO, and CO2) and HCl, dissolved in the water, have been performed. No effect on the hydrophobic water gap was found.