Fluorescence studies on mixed micelles of ionic-nonionic surfactants

Abstract

Fluorescence properties of ionic dyes using oppositely charged non-fluorescent dyes as quenchers in mixed surfactant of ionic-nonionic systems have been investigated. Cationic dye safranin O and anionic dye eosin Y are used as probes; bromocresol green, thymol blue and bromothymol blue are used as quenchers for safranin O, and crystal violet, toluidine blue and methylene blue are used as quenchers for eosin Y. The fluorescence characteristics in mixed micellar media of ionic and nonionic surfactants CTAB, CpC1, SDS, AOT, Triton X-100, Tween 20, and Brij 35 have been studied. The variations in the physico-chemical parameters. viz., cmc, aggregation number(n), binding constant between the quencher and the probe <em>(K</em>_SV), occupancy number of the quencher in the micelles (ń), the binding constant of the quencher with the micelle <em>(K) </em>in such interactions have been evaluated using suitable equations and the properties have been explained in terms of the micellar structures.