American Chemical Society
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Green Synthesis, Surface Activity, Micellar Aggregation, and Corrosion Inhibition Properties of New Gemini Quaternary Ammonium Surfactants

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journal contribution
posted on 2018-04-30, 19:17 authored by Hongqin Liu, Xiqin Zhou, Xiaoxu Zhang, Guoying Shi, Jun Hu, Changyao Liu, Baocai Xu
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 the using green reagent dimethyl carbonate. The structures of these surfactants were confirmed by Fourier transform infrared spectroscopy, 1H NMR, 13C NMR, and mass spectra. Their surface activities and aggregation properties 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·kg–1 and self-assemble spontaneously into double layer aggregates which are mostly single-room vesicles and multilamellar vesicles. Furthermore, with increasing alkyl chain length, their critical micelle concentration values and the degree of counterion binding (β) 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.