Ultrafast dynamics of water in cationic micelles
Ultrafast dynamics of water in cationic micelles
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DOI：
10.1063/1.2721527
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发表时间：
2007-03-28
影响因子：
4.4
通讯作者：
Bakker, Huib J.
中科院分区：
文献类型：
--
作者：
Dokter, Adriaan M.;Woutersen, Sander;Bakker, Huib J.
研究了阳离子反胶团中水的禁闭效应对液态水动力学性质的影响。作者在不同大小的十六烷基三甲基溴化铵（CTAB）反胶团中对同位素稀释的HDO在D2 O中的OH伸缩振动进行了中红外超快泵浦-探测光谱。作者观察到，表面活性剂抗衡离子是不均匀分布在整个反胶束，极端盐度的区域发生在界面斯特恩层附近。作者发现，胶束的核心中的水分子表现出类似的取向动力学作为散装水，和反离子丰富的界面区域的水分子是少得多的移动的。一个明确的比较与阴离子双（2-乙基己基）磺基琥珀酸钠（AOT）反胶团中的水动力学。结果表明，阳离子CTAB反胶团中的界面水比阴离子AOT反胶团中的水具有更高的取向迁移率。(c)2007年，美国物理学会。
The effect of confinement on the dynamical properties of liquid water is investigated for water enclosed in cationic reverse micelles. The authors performed mid-infrared ultrafast pump-probe spectroscopy on the OH-stretch vibration of isotopically diluted HDO in D2O in cetyltrimethylammonium bromide (CTAB) reverse micelles of various sizes. The authors observe that the surfactant counterions are inhomogeneously distributed throughout the reverse micelle, and that regions of extreme salinity occur near the interfacial Stern layer. The authors find that the water molecules in the core of the micelles show similar orientational dynamics as bulk water, and that water molecules in the counterion-rich interfacial region are much less mobile. An explicit comparison is made with the dynamics of water confined in anionic sodium bis(2-ethythexyl) sulfosuccinate (AOT) reverse micelles. The authors find that interfacial water in cationic CTAB reverse micelles has a higher orientational mobility than water in anionic AOT reverse micelles. (c) 2007 American Institute of Physics.