Local dynamics of micelles of new long-chain surfactants in aqueous media

被引:0
|
作者
M. V. Motyakin
L. L. Yasina
A. M. Wasserman
L. Z. Rogovina
V. N. Matveenko
机构
[1] Russian Academy of Sciences,Semenov Institute of Chemical Physics
[2] Russian Academy of Sciences,Nesmeyanov Institute of Organoelement Compounds
[3] Moscow State University,Department of Chemistry
来源
Colloid Journal | 2010年 / 72卷
关键词
Surfactant; Surfactant Concentration; Surfactant Molecule; Colloid Journal; Micellar Solution;
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摘要
The molecular dynamics, organization, and phase state of aqueous solutions of new long-chain cationic surfactants with saturated hydrocarbon radicals (from C16 to C22) containing one or two hydroxyl groups in their polar heads are studied by the spin-probe EPR spectroscopy. In the region of micellar solutions, local mobility of surfactant molecules slightly changes with an increase in the length of hydrocarbon radical, whereas the order parameter of micelles increases notably. The addition of two hydroxyl groups to the polar part of long-chain (C22) surfactant molecule considerably decreases local mobility and increases the ordering of micellar system compared to the micelles of analogous surfactant with one hydroxyl group. Phase transition from micellar to a solid state is observed in this system with a decrease in temperature. The addition of KCl to aqueous surfactant solution lowers the local mobility, increases the order parameter of micelles, and can cause changes in the phase state of a system. In the presence of salt, the correlation time of probe rotation and its order parameter depend on surfactant concentration. Apparently, this is explained by changes in the shape of micelles upon variations in surfactant concentration.
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页码:31 / 39
页数:8
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