A number of techniques, including conductivity, surface tension, dynamic light scattering, transmission electron microscopy, and 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared (FT-IR), and 1H-1H 2D nuclear Overhauser effect spectroscopy (1H-1H 2D NOESY), have been used to investigate the effect of amide bonds on the interfacial and assembly properties of a cationic surfactant, N-anilinoformylmethyl-N-cetyl-N,N-dimethyl ammonium chloride (AMC-C 16 ), in aqueous solutions. The adsorption of AMC-C 16 has been found to be much better than that of the conventional cationic surfactant, benzyl cetyldimethylammonium chloride (BAC-16) at the air/water interface and in solution. The surface tension measurements show the presence of two critical aggregation concentrations (CAC1 and CAC2) for AMC-C 16 . The presence of a strong intermolecular hydrogen bond of AMC-C 16 was confirmed by 1H NMR and FT-TR. The molecular interactions of AMC-C 16 were detected by 1H-1H 2D NOESY. The results show that the rigid group (phenyl) of AMC-C 16 was partially overlapped with its alkyl chain in aqueous solution, and the possible aggregation behavior for AMC-C 16 was proposed. The effects of an inorganic salt (NaCl) and an organic salt (C6H5COONa) to the aggregates of AMC-C 16 have been discussed.
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