Micellar solutions of sulfobetaine Surfactants in water-ethylene glycol mixtures:: Surface tension, fluorescence, spectroscopic, conductometric, and kinetic studies
Micellar solutions of sulfobetaine Surfactants in water-ethylene glycol mixtures:: Surface tension, fluorescence, spectroscopic, conductometric, and kinetic studies
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DOI：
10.1021/la050862j
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发表时间：
2005-08-02
期刊：
影响因子：
3.9
通讯作者：
Moyá, ML
中科院分区：
文献类型：
--
作者：
Graciani, MD;Rodríguez, A;Moyá, ML
用表面张力法研究了水-乙二醇(EG)、N-十二烷基、N-十四基和N-十六烷基-N，N-二甲基-3-氨基-1-丙磺酸盐(分别为SB3-12、SB3-14和SB3-16)胶束溶液中的胶束作用。通过荧光和光谱测量，获得了添加EG对磺基甜菜碱胶束聚集数和胶束界面区极性的影响。表面张力测量还提供了表面过剩浓度、每个表面活性剂分子的最小面积、CME处的表面压力和标准吉布斯吸附能与添加的有机溶剂的重量百分比的关系的信息。通过表面张力的测定，估算了水-EG混合物的Gordon参数。由EG的存在引起的热力学和结构变化控制了在水-EG磺基甜菜碱胶束溶液中观察到的4-硝基苯磺酸甲酯与BR-反应的胶束动力学效应。通过电导测量获得了溴离子在体相和胶束假相之间的分布信息。用假相动力学模型定量解释了动力学胶束效应。
Micellization in water-ethylene glycol (EG) N-dodecyl, N-tetradecyl, and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB3-12, SB3-14, and SB3-16, respectively) micellar solutions, with the weight percent of EG changing within the range 0-40, was studied by means of surface tension measurements. Information about the influence of the added EG on the aggregation number of the sulfobetaine micelles and on the polarity of the interfacial region of micelles was obtained through fluorescence and spectroscopic measurements. Surface tension measurements also provide information about the dependence of the surface excess concentration, the minimum area per surfactant molecule, the surface pressure at the cme, and the standard Gibbs energy of adsorption on the added weight percent of the organic solvent. The Gordon parameter of the water-EG mixtures was also estimated by means of surface tension measurements. The thermodynamic and structural changes originated by the presence of EG control the micellar kinetic effects observed in the reaction methyl 4-nitrobenzenesulfonate + Br- occurring in the water-EG sulfobetaine micellar solutions. Information about the distribution of bromide ions between the bulk and micellar pseudophases was obtained through conductivity measurements. The kinetic micellar effects were quantitatively explained by using the pseudophase kinetic model.