SOLUBILIZATION BEHAVIOR OF MIXED SURFACTANT MICELLES IN CONNECTION WITH THEIR ZETA POTENTIALS

Solubilization and zeta potential measurements have been made of the mixed micelles of dodecyl polyoxyethylene ether (DPOE) and sodium dodecylpolyoxyethylene sulfate (SDPS) with an equal number of oxyethylene units in the presence of added electrolytes to understand a relation between the solubilizing power and zeta potential of the micelles. The solubilizing power of the mixed micelle toward and oil-soluble dye, Yello OB, increases with increasing ratio of DPOE/SDPS, whereas the zeta potential of the micelle decreases with the ratio of DPOE/SDPS. Initial changes in both solubilizing power and zeta potential with addition of a small amount of DPOE to SDPS are considerable. It has been shown that the solubilizing power is closely related to the zeta potential of the micelle and that there is a simple linear correlation between these two characteristics, especially in the presence of calcium chloride. © 1968.