Aggregation Behavior of 1-Dodecyl-3-methylimidazolium Bromide in Aqueous Solution: Effect of Ionic Liquids with Aromatic Anions

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• 作者：Yingqiu Gu ; Lijuan Shi ; Xiyuan Cheng ; Fei Lu ; Liqiang Zheng
• 刊名：Langmuir
• 出版年：2013
• 出版时间：May 28, 2013
• 年：2013
• 卷：29
• 期：21
• 页码：6213-6220
• 全文大小：519K
• 年卷期：v.29,no.21(May 28, 2013)
• ISSN：1520-5827

文摘

The effects of ionic liquids (ILs), 1-butyl-3-methylimidazolium methylsulfonate (bmimMsa), 1-butyl-3-methylimidazolium benzenesulfonate (bmimBsa), and 1-butyl-3-methylimidazolium 2-naphthalenesulfonate (bmimNsa), on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide (C₁₂mimBr) in aqueous solution were investigated by surface tension, dynamic light scattering measurements, and ¹H NMR spectroscopy. The ability to promote the surfactant aggregation is in the order bmimNsa > bmimBsa > bmimMsa. Nevertheless, only bmimNsa distinctly reduces both the CMC value and the surface tension at CMC. Due to the penetration of C₁₀H₇SO₃^{鈥?/sup>anions into the surfactant aggregate, bmimNsa is found to induce a phase transition from micelles to vesicles, whereas the other ILs only slightly increase the sizes of micelles. The combined effect of intermolecular interactions, such as hydrophobic effect, electrostatic attractions, and 蟺鈥撓€ stacking interactions, is supposed to be responsible for this structural transformation, in which 蟺鈥撓€ stacking plays an important role.}