SOLUBILIZATION OF WATER-INSOLUBLE DYE BY A COOPERATIVE BINDING SYSTEM OF SURFACTANT AND POLYELECTROLYTE

Solubilization of a water-insoluble dye, oil yellow OB (OY), is examined in poly(vinyl sulfate)-alkyltrimethylammonium complexes as a function of the degree of surfactant binding. Solubilization correlates strongly to the degree of cooperative binding of surfactant. The binding isotherms of surfactant shift to lower equilibrium concentration of free surfactant in the presence of solubilized dye. A concerted cooperative binding model of dye and surfactant is proposed for this solubilization. The model predicts the solubilization of OY and surfactant binding in the presence of OY. The free energy of transfer of OY from the solid phase to polyion/surfactant complex is found to be 3.1 kJ mol-1 from the solubilizing capacity. © 1990, American Chemical Society. All rights reserved.