Effects of structure dissymmetry on aggregation behaviors of quaternary ammonium Gemini surfactants in a protic ionic liquid EAN.
Effects of structure dissymmetry on aggregation behaviors of quaternary ammonium Gemini surfactants in a protic ionic liquid EAN.
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DOI：
10.1021/la304004u
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发表时间：
2012-11
期刊：
影响因子：
--
通讯作者：
Xudong Wang;Qintang Li;Xiao Chen;Zhihong Li
中科院分区：
文献类型：
--
作者：
Xudong Wang;Qintang Li;Xiao Chen;Zhihong Li
The aggregation behaviors of a series of dissymmetric cationic Gemini surfactants, [C(m)H(2m+1)(CH(3))(2)N(CH(2))(2)N(CH(3))(2)C(n)H(2n+1)]Br(2), designated as m-2-n (with a fixed m + n = 24, m = 16, 14, 12) have been investigated in a protic ionic liquid, ethylammonium nitrate (EAN). Surface tension, polarized optical microscopy (POM), small-angle X-ray scattering (SAXS), and rheological measurements are adopted to investigate the micellization and lyotropic liquid crystal (LLC) formation. The obtained results indicate that the structure dissymmetry plays an important role in aggregation process of m-2-n. With increasing degree of dissymmetry, the critical micellization concentration, the maximum reduction of solvent surface tension, and the minimum area occupied per surfactant molecule at the air/EAN interface all become smaller. The thermostability of formed LLCs is therefore improved because of the more compact molecules. These characteristics can be explained by the enhancement of solvophobic effect due to the increased structure dissymmetry of Gemini surfactants.
