Effects of dioctadecyl dimethyl ammonium chloride on the rheological behavior of behenyl trimethyl ammonium chloride/1-hexadecanol/water ternary system

The effects of dioctadecyl dimethyl ammonium chloride (DODAC) on the rheological properties of ternary systems consisting of behenyl trimethyl ammonium chloride (C22TAC), 1-hexadecanol (C16OH), and water are studied to improve the long-term stability and to establish the preparation method of cosmetic products. The basic ternary systems behave as solids at low stresses, due to the formation of lamella liquid crystals called α gel. The additions of DODAC to ternary systems cause the rupture of α gel structures and transformation to vesicles. The structures of molecular assemblies are confirmed through particle size distribution, differential scanning calorimetry, and freeze fracture electron microscopy. The vesicle structures formed in coexistence of single-chain surfactant and double-chain surfactant are highly stable. Because the quaternary systems are considered to be constructed by the mixtures of α gel and vesicles at the appropriate concentrations of DODAC, the rheology can be controlled by the structural balance between them.

The additions of dioctadecyl dimethyl ammonium chloride to ternary systems cause the reduction of viscosity. The double step curves imply the existence of two different molecular assemblies.Figure optionsDownload as PowerPoint slide