Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

A new series of gemini quaternary ammonium surfactants containing amide groups with the formula CnH2n+1CONH(CH2)2N+(CH3)2(CH2)2 N+(CH3)2(CH2)2NHCOCnH2n+1*2CH3CO3- (n=11,13,15,17) have been synthesized by using green reagent -- dimethyl carbonate. The structures of these surfactants were confirmed by FT-IR, 1H-NMR, 13C-NMR and mass spectra. The surface activities and aggregation properties of them were investigated by surface tension, conductivity, steady-state fluorescence, dynamic light scattering and transmission electron microscope measurements. The results show that these synthesized gemini quaternary ammonium surfactants reduce the surface tension of water to a minimum value of 28.21 mN*m-1 at a concentration of 0.256 mmol*L-1 and self-assemble spontaneously into double layer aggregates which are mostly single-room vesicles and multilamellar vesicles. Furthermore, with increasing alkyl chain length, the critical micelle concentration (CMC) values and the degree of counterion binding () of them decrease; and the spontaneous tendency of vesicle formation and the micellar aggregation numbers (Nm) increase. They are also found to be effective corrosion inhibitors for A3 steel in acid solution.