Aggregation behavior and reactivity of <i>N</i>-alkyl-<i>N</i>,<i>N</i>-dimethyl-<i>N</i>-(2,3-epoxy propyl) ammonium chloride

A series of epoxy-functionalized quaternary ammonium surfactants consisting of different alkyl chains (C10–C18) were synthesized. Their aggregation behaviors in aqueous solution, as well as antibacterial activity and reactivity were investigated. The cmc, γcmc, πcmc, pc20 and cmc/c20 suggested that the presence of epoxy group increased the surface activity of ADEAC. This is ascribed to the hydrogen bonding effect between the adjacent hydrophilic groups. The surface activity increased with the increase of hydrocarbon chain length. The thermodynamic parameters indicated that the micellization process was entropy-driven at high temperature, and enthalpy-driven at low temperature. The activation energy of conductance and micelle aggregation number were also calculated. The antibacterial activity of ADEAC against Gram-negative bacteria was stronger than that for Gram-positive ones, and N-dodecyl-N,N-dimethyl-N-(1,2-epoxy propyl) ammonium chloride showed the most effective antibacterial activity. The synthesis of N-hexadecyl-N,N-dimethyl-N-(1,2-epoxy propyl) ammonium chloride (HDEAC) modified chitosan demonstrated the reactivity of HDEAC.