DILUTE PHASE-BEHAVIOR OF CETYL ALCOHOL, SODIUM LAURYL SULFATE, AND WATER

A ternary phase diagram of cetyl alcohol (CA), sodium lauryl sulfate (SLS), and water is constructed at room temperature in the dilute corner with a composition range of 96-100 wt % water, and 4-0 wt % of the surfactant and alcohol. Thephase behavior is examined though differential scanning calorimetry and associated with the polymorphism of CA. Three different phases are observed: (i) a gel phase, (ii) a coagel phase, and (iii) a micellar solution of SLS and crystals of CA. With aging, certain regions of the gel transform into the coagel phase. This transformation and the existence of the micelle + & crystal region are related to the collapse of the bilayer structure of the gel. © 1990, American Chemical Society. All rights reserved.