We studied the physicochemical properties of 1:1 stoichiometric complexes of acylglutamic acids (CnGlu) with tertiary alkylamines (CnDMA) in water at their low and high concentrations. Static surface tensiometry suggested that the critical micelle concentration (cmc) decreased with increasing hydrophobic chain length of the complexes. In addition, CnGlu-CnDMA yielded lower cmc than the C12Glu single system. In the region of high concentrations, several phase states including isotropic liquid (L1) phase, hexagonal liquid crystal (H1) phase, bicontinuous cubic liquid crystal (V1) phase, and lamellar liquid crystal (Lα) phase were observed. Assemblies with lesser positive curvature tend to be formed with increasing complex concentration, increasing temperature, and increasing hydrophobic chain length. Additionally, the complex formation resulted in the molecular assemblies with lesser positive curvature.
Keywords: acylglutamic acid; alkylamine; gemini surfactant; liquid crystal; surface tension.