α-Gel Prepared in Sodium Methyl Stearoyl Taurate/ Behenyl Alcohol/Water System-Characterization of Structural Changes with Water Concentration

摘要

In this study, the changes in the structural and physicochemical properties of an α-crystalline phase (often called an "α-gel") were assessed in a sodium methyl stearoyl taurate (SMT)/behenyl alcohol/ water system. The a-gels were characterized focusing on the effects of the alcohol/surfactant ratio and water concentration. Water molecules solubilized in the interlayer of the α-crystalline phase resulting in expanded interlayer spacing. Beyond the solubilization limit of 85 %, water molecules were trapped in the matrix of the a-crystalline phase in non-equilibrium (i.e., two phases). Accordingly, different self-diffusion coefficients for the solubilized and trapped water molecules were measured using a Fourier transform pulsed gradient spin echo technique to monitor the 'H NMR spectra. It was concluded that the two self-diffusion coefficients correspond to the water solubilized in the interlayer, i.e., "slow water," and trapped in the matrix of the a-crystalline phase, i.e., "fast water."