SOLUBILIZATION OF AMPHIPHILIC HEMICYANINE DYES BY A CATIONIC SURFACTANT, CETYLTRIMETHYLAMMONIUM BROMIDE

The solubilization of amphiphilic hemicyanine dyes by the micelles of a cationic surfactant? cetyltrimethylammonium bromide (CTAB), was stud ied as a function of surfactant concentration above the critical micel le concentration(CMC). The micelle-water partition coefficient, K-x, a nd the standard free energy of solubilization, Delta G(0), of these dy es in CTAB micelles was determined at 25.0 degrees C by a differential spectroscopic method. The CMCs of CTAB in the presence of small amoun ts of these dyes were determined by a conductivity method at 25.0 degr ees C. The values of K-x and Delta G(0) for all six dyes were determin ed by an improved method that incorporates both conductance and differ ential absorbance data. (C) 1997 Academic Press.