Synthesis and aggregation behaviors of a new bis-quaternary ammonium surfactant

Abstract

Abstract A bis-quaternary ammonium surfactant containing two head groups connected with a propylene spacer coco-tri(hydroxyethyl)-dimethylpropane diammonium chloride (CTHDAC) was synthesized through a two-step reaction process. The two head groups were connected with a propylene spacer, which is distinguished from other surfactants with double head groups, such as gemini and bola form surfactants. Its molecular structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance ( 1 HNMR). CTHDAC could decrease the surface tension to 39.12 mN/m with the CMC being 4.58 mmol/L. In the contact angle measurement, CTHDAC performed poor compared with dodecyl trimethylamine chloride (DTAC). Further, electrical conductivity, fluorescence property, particle size analysis and TEM micrographs were operated to investigate the aggregation behaviors of CTHDAC in aqueous solution. The results indicate that the large hydrophilic area caused by the strong electrostatic repulsion between head groups makes CTHDAC show a loose arrangement at air/water interface and in the formation of micelles. In addition, the size of aggregates of CTHDAC in aqueous solution is around 200 nm which is irregular spherical.