SPECTROSCOPIC STUDIES OF THE INTERACTION OF THE DYE SAFRANINE-T WITH BRIJ MICELLES IN AQUEOUS-MEDIUM

The visible spectra of safranine T (ST) in micellar solutions of Brij 52, Brij 56 and Brij 58 indicate 1 : 1 charge transfer complex formati on of ST with non-ionic Brij micelles. The complexing strength follows the order Brij 52 > Brij 56 > Brij 58. The fluorescence spectra of ST in micellar solutions of Brij also support 1 : 1 ST-micelle complex f ormation as in the ground state. The equilibrium constant of the dye-m icelle complex is directly proportional to the micellar aggregation nu mber and inversely proportional to the surfactant critical micellar co ncentration (CMC). The solvent parameters, i.e. the Kosower Z value, i ntramolecular charge transfer energy E-T(30) and dielectric constant o f the micellar medium, were evaluated. The binding constant, micellar aggregation number and solvent parameters remain constant over a certa in range of Brij concentration, but vary beyond this range. (C) 1997 E lsevier Science S.A.