Mixed Monolayer and Micelle Formation of Cationic and Zwitterionic Surfactant of Identical Hydrocarbon Tail in an Aqueous Medium: Interfacial Tension, Fluorescence Probe, Dynamic Light Scattering, and Viscosity Studies
Mixed Monolayer and Micelle Formation of Cationic and Zwitterionic Surfactant of Identical Hydrocarbon Tail in an Aqueous Medium: Interfacial Tension, Fluorescence Probe, Dynamic Light Scattering, and Viscosity Studies
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DOI：
10.1080/01932690701716028
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发表时间：
2008-02
影响因子：
2.2
通讯作者：
P. Sehgal;H. Doe;R. Wimmer;R. Tanaka;Osamu Kosaka
中科院分区：
文献类型：
--
作者：
P. Sehgal;H. Doe;R. Wimmer;R. Tanaka;Osamu Kosaka
通过测定界面张力、荧光、动态光散射（DLS）和粘度，研究了由具有相同烃尾但不同极性头基的阳离子表面活性剂十二烷基三甲基溴化铵（DTAB）和两性表面活性剂十二烷基铵丙磺酸二甲酯（DPS）混合形成的混合单分子膜和混合胶束的性质。从界面张力测量的结果，各种界面和体积参数，如最大表面过剩，在临界胶束浓度的表面压力，和标准的界面吸附和胶束化的自由能进行了评价。根据克林特理论讨论了混合胶团与理想胶团的偏离。用正规溶液理论计算了混合胶束和混合单分子膜中的相互作用参数，以及混合胶束和混合单分子膜的组成。用静态荧光猝灭法测定了纯胶束和混合胶束的平均聚集数。以罗丹明B（RB）为荧光探针，通过荧光偏振法测定了纯胶束和混合胶束的微粘度。通过动态光散射（DLS）测量，得到了不同表面活性剂摩尔分数下胶束的流体动力学半径。DTAB的粘度随α的变化出现最小值，在高浓度表面活性剂混合物中，粘度向高α方向移动。这一最小值表明混合胶束的结构变化。
We have studied the properties of the mixed monolayers and the mixed micelles formed from the mixture of the cationic surfactant dodecyltrimethylammonium bromide (DTAB) and the zwitterionic surfactant dimethyldodecylammoniopropanesulfonate (DPS), that have the identical hydrocarbon tail but different polar head groups, by measuring interfacial tension, fluorescence, dynamic light scattering (DLS), and viscosity. From the results of interfacial tension measurements, the various interfacial and bulk parameters such as the maximum surface excess, the surface pressure at the critical micellar concentration, and the standard free energies of interfacial adsorption and of micellization have been evaluated. The deviation from the ideal of the mixed micelles has been discussed on the basis of Clint theory. The interaction parameters in the mixed micelles and in the mixed monolayers, and also the compositions of the mixed micelles and the mixed monolayers were obtained with the help of regular solution theory. From a static fluorescence quenching method, the mean micellar aggregation number of pure and mixed micelles was obtained. Microviscosity in the pure and mixed micelles was monitored by fluorescence polarization measurements using Rhodamine B (RB) as a fluorescence probe. The hydrodynamic radii of the micelles were obtained in the mixtures at different mole fractions of surfactant from DLS measurements. The change of viscosity with α of DTAB revealed a minimum, and it was shifted to a higher αvalue in the mixture of high concentration of surfactant. This minima suggested a structural change in the mixed micelles.