Aggregation behavior of imidazolium-based chiral surfactant in aqueous solution

作者:Gao, Hejun; Shi, Lijuan; Zhang, Shaohua; Li, Jun; Wang, Xiaodong; Zheng, Liqiang*
来源:Colloid and Polymer Science, 2013, 291(5): 1077-1084.
DOI:10.1007/s00396-012-2830-8

摘要

A novel imidazolium-based chiral surfactant with a Y-type hydrophobic chain, (S)-(+)-1-(2,3-bis(octanoyloxy)propyl)-3-methylimidazolium chloride ([Bopmim]Cl), was synthesized. The aggregation behavior of [Bopmim]Cl in aqueous solution was then investigated by surface tension, electrical conductivity, H-1 NMR, and fluorescence measurements. Compared with [C(12)mim]Cl, the critical micelle concentration for [Bopmim]Cl is lower, indicating that the novel chiral surfactant has superior capacity to form micelles. A larger value of pC(20), a greater minimum area per surfactant molecule (A(min)), a smaller degree of counterion binding (beta), and a looser aggregate are caused by the relatively larger Y-type hydrophobic chain of [Bopmim]Cl. Furthermore, analysis of the H-1 NMR spectra revealed that the introduced Y-type hydrophobic chain may prevent the hydrophobic group from forming an extended chain configuration and cause a change-over from trans to gauche conformations upon micellization. The micelles of the novel chiral surfactant may provide some potential applications in the stereochemical recognition of surfaces or of biological structures.

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