An X-ray Reflectivity Study of the Water-Docosane Interface
An X-ray Reflectivity Study of the Water-Docosane Interface
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水-二十二烷界面的 X 射线反射率研究
DOI：
10.1021/jp001377u
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. Schlossman
中科院分区：
文献类型：
--
作者：
A. Tikhonov;D. M. Mitrinovic;Ming Li;Zhengqing Huang;M. Schlossman
用同步辐射X射线反射率法研究了体水与正二十二烷(C22H46)界面垂直的电子密度分布。这些测量用误差函数电子密度分布来解释，得到的界面宽度为5.7±0.2A。与先前在水−正己烷界面上的测量相比，该界面宽度与毛细管波理论的预测结果σ帽=3.5A截然不同，该宽度可以通过结合毛细管波预测和由于二十二烷的本体关联长度而来自本征结构的贡献来解释。我们还讨论了在该界面上没有界面冻结的现象，这是在烷烃−蒸气和烷烃−硅氧化物界面上观察到的类似链长的正构烷烃的现象。
Synchrotron X-ray reflectivity is used to study the electron density profile normal to the interface between bulk water and bulk n-docosane (C22H46). These measurements are interpreted in terms of an error function electron density profile to yield an interfacial width of 5.7 ± 0.2 A. In contrast with an earlier measurement on the water−hexane interface, this interfacial width disagrees sharply with the prediction from capillary wave theory, σcap = 3.5 A. This width can be accounted for by combining the capillary wave prediction with a contribution from intrinsic structure due to the bulk correlation length of docosane. We also discuss the absence of interfacial freezing at this interface, a phenomenon observed for n-alkanes of a similar chain length at the alkane−vapor and alkane−silicon oxide interfaces.