Phase Behavior and Dielectric Spectroscopy of the Sodium Dodecyl Trioxyethylene Sulfate/n-Butanol/Water System

The phase diagram of the ternary system of sodium dodecyl trioxyethylene sulfate (SDES)/ n butanol/water is obtained at (30 0±0 1) ℃. There exists a clear, isotropic, and low viscosity L phase, which could be divided into W/O micelle, bi continuous (B.C.) phase and O/W micelle by conductivity measurements. Dielectric Relaxation Spectroscopy (DRS) measurements are applied to investigate microstructure changes of this system. For samples with a fixed weight ratio, SDES/ n butanol=3/7, DRS indicates a structure transition from W/O to O/W micelles via B.C. phase with the increase of water content. For the samples with a fixed weight ratio, SDES/H 2O=4/6, DRS can presents that there exist changes of onefold structure size of W/O micelles as n butanol content increases. The results obtained from DRS and their analyses are in good agreement with those from phase diagram and conductivity measurements.