title: NMR study of the dynamics of cationic gemini surfactant 14-2-14 in mixed solutions with conventional surfactants.
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.
authors.affiliation: Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Xing-Yu
authors.initials: XY
authors.lastname: Lu
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Shi-Zhen
authors.initials: SZ
authors.lastname: Mao
authors.forename: Mai-Li
authors.initials: ML
authors.lastname: Liu
authors.forename: Ping-Ya
authors.initials: PY
authors.lastname: Luo
authors.forename: You-Ru
authors.initials: YR
authors.lastname: Du
mesh_terms: D002412:Cations / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008823:Micelles; D017830:Octoxynol / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D050337:Trimethyl Ammonium Compounds / Q000737:chemistry
chemical_list: C542556:14-2-14 gemini surfactant; D002412:Cations; D008823:Micelles; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D013501:Surface-Active Agents; D050337:Trimethyl Ammonium Compounds; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D017830:Octoxynol; C515901:Brij 35; C009410:tetradecyltrimethylammonium