INFLUENCE OF A CATIONIC SURFACTANT ON THE PHASE-BEHAVIOR OF C(12)E(4)HEXANOL/WATER SYSTEM AT LOW SURFACTANT CONCENTRATION/

The influence of the ionic charge on the phase behavior of C(12)E(4)/h exanol/water system at low surfactant concentration has been studied. The charge density of the system has been changed by replacing nonioni c surfactant with cationic surfactant and adding NaBr salt. The L(3) p hase disappears in the presence of the cationic surfactant and it appe ars again when the charge is screened with NaBr salt. On the contrary, the L(1) phase is only present in the presence of the cationic surfac tant. The resulting lamellar phase shows very different macroscopic pr operties with the hexanol concentration and with the cationic surfacta nt concentration. The theologic study of the uniphasic solutions shows that with the cationic surfactant the lamellar phase is a plastic sys tem with yield stress values.