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NMR study of the dynamics of cationic gemini surfactant 14-2-14 in mixed solutions with conventional surfactants.

The journal of physical chemistry. B (2009-05-26)
Yan Jiang, Xing-Yu Lu, Hong Chen, Shi-Zhen Mao, Mai-Li Liu, Ping-Ya Luo, You-Ru Du
RESUMEN

Three kinds of conventional surfactants, namely, two nonionic surfactants [polyethylene glycol (23) lauryl ether (Brij-35) and Triton X-100 (TX-100)], one cationic surfactant [n-tetradecyltrimethyl ammonium bromide (TTAB)], and an anionic surfactant [sodium n-dodecyl sulfate (SDS)}, were mixed into the quaternary ammonium gemini surfactant [C(14)H(29)N(+)(CH(3))(2)](2)(CH(2))(2).2Br(-) (14-2-14) in aqueous solution. The exchange rate constants between 14-2-14 molecules in the mixed micelles and those in the bulk solution were detected using two nuclear magnetic resonance (NMR) methods: one-dimensional (1D) line shape analysis and two-dimensional (2D) exchange spectroscopy (EXSY). The results obtained from these two methods were consistent. Both showed that mixing a nonionic conventional surfactant, either Brij-35 or TX-100, enhanced the exchange process between the 14-2-14 molecules in the mixed micelles and those in the bulk solution. In contrast, the anionic surfactant SDS and the cationic surfactant TTAB slowed the process slightly.

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Sigma-Aldrich
Myristyltrimethylammonium bromide, ≥99%
Sigma-Aldrich
Trimethyl-tetradecylammonium chloride, ≥98.0% (AT)
Sigma-Aldrich
Myristyltrimethylammonium bromide, 98% (AT)
Supelco
Myristyltrimethylammonium bromide, suitable for ion pair chromatography, LiChropur, ≥99.0% (AT)