Synthesis, spectroscopic studies, aggregation and surface behavior of hexamethylene-1,6-bis(N,N-dimethyl-N-dodecylammonium bromide)

Abstract

Gemini surfactant, hexamethylene-1,6-bis(N,N-dimethyl-N-dodecylammonium bromide) (12-6-12), was synthesized without solvent, in a short time and with a very good yield. The chemical structure and purity of synthesized dimeric quaternary ammonium salt were confirmed by FT-IR and NMR spectroscopies. The interfacial properties (area occupied by one molecule, adsorption and surface excess concentration of 12-6-12 at the water-air interface), and the aggregation behavior were examined. The critical micelle concentration (cmc) was determined by the surface tension, density, dynamic viscosity and specific conductivity measurements. Standard Gibbs free energy of micellization and apparent and partial molar volumes of surfactant we have also studied. The surface and biological activity against fungi (Aspergillus niger, Penicillium chrysogenum, Candida albicans) show that hexamethylene-1,6-bis(N,N-dimethyl-N-dodecylammonium bromide) has much higher activity than its monomeric analog, i.e. dodecyl trimethyl ammonium bromide. Simple, fast end efficient synthesis without solvent is in good agreement with rules of green chemistry. Unique properties and aggregation behavior of this cationic gemini surfactant, which were examined in details and described in this work, have proved that this compound can be used in many various applications, among the others in smart materials.