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

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
ABSTRACT

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.

MATERIALS
Product Number
Brand
Product Description

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