Effects of cetylpyridinium chloride on phase and rheological behavior of the diluted C12E4/benzyl alcohol/water system

The influence of a small amount of cetylpyridinium chloride on the phase di agram of the diluted C12E4/benzyl alcohol/water system is studied. The pres ence of the ionic surfactant results in the stabilization of the vesicles i n relation to the open bilayers, The bilayer structures are less sensitive to shear effects than for the system without cationic surfactant, Moreover, the formation of the mixed micelle phase is also favored. The transition f rom spherical to rod micelles has been detected from viscosity measurements , The micelles located close to the two-phase region (at the lower amount o f cationic surfactant) are the largest and most flexible micelles. (C) 2000 Academic Press.