Effect of the Nature of the Spacer on the Aggregation Properties of Gemini Surfactants in an Aqueous Solution
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- 作者：Xiaoyong Wang ; Jinben Wang ; Yilin Wang ; Haike Yan ; Peixun Li ; and Robert K. Thomas
- 刊名：Langmuir
- 出版年：2004
- 出版时间：January 6, 2004
- 年：2004
- 卷：20
- 期：1
- 页码：53 - 56
- 全文大小：56K
- 年卷期：v.20,no.1(January 6, 2004)
- ISSN：1520-5827
文摘
The aggregation properties of three dicationic quaternary ammonium gemini surfactants with the samestructure, except the spacer group, diethyl ether, six methylene, and p-xylyl, have been studied usingelectrical conductivity and fluorescence. The critical micelle concentration (cmc) and the micelle aggregationnumber (N) were determined, and the micropolarity and the microviscosity of the micelle were characterized.The micelle ionization degree (
) was obtained by a combination of the electrical conductivity data andthe micelle aggregation number. Furthermore, the Gibbs free energy of micellization (
Gmic) was studied.These results have shown that the nature of the spacer has an important effect on the aggregation propertiesof gemini surfactants in an aqueous solution. A hydrophilic, flexible spacer prompts micelle formation,which leads to a smaller cmc, smaller , larger N, and more negative Gmic. Meanwhile, the microviscositystudy indicates that the gemini surfactant with a hydrophilic, flexible spacer forms a more closely packedmicelle structure than the one with a hydrophobic, rigid spacer.
) was obtained by a combination of the electrical conductivity data andthe micelle aggregation number. Furthermore, the Gibbs free energy of micellization (Gmic) was studied.These results have shown that the nature of the spacer has an important effect on the aggregation propertiesof gemini surfactants in an aqueous solution. A hydrophilic, flexible spacer prompts micelle formation,which leads to a smaller cmc, smaller , larger N, and more negative Gmic. Meanwhile, the microviscositystudy indicates that the gemini surfactant with a hydrophilic, flexible spacer forms a more closely packedmicelle structure than the one with a hydrophobic, rigid spacer.