Physicochemical characterization of reverse micelles of Triton X using 1-anthracene sulphonate as fluorescent probe: A spectroscopic study

The aggregation of surfactant of polyoxyethylene-p-(1,1,3,3-tetramethylbutyl) phenyl ether (Triton X) series in chloroform has been studied. The critical micellar concentration (cmc) of the reverse micelles formed has been determined by four different techniques. The determined cmc values by various techniques are close to each other and facilitate determination of the free energy change (Delta G) values associated with the micellization. From the correlation of cmc with hydrophile-lipophile balance (HLB) it was found that cmc decreases with decrease in HLB values. The association constant of the reverse micelle with fluorescent probe 1-anthracene sulphonate (1-AS) and micellar aggregation number has been evaluated. The location of the fluorophore in the reverse micelle and the polarity of the micelle solubilized sites have been determined from the E-T(30), Kosower Z, and dielectric constant values. The pH of the aqueous region of reverse micelles has been estimated by comparison method. (C) 2009 Elsevier B. V. All rights reserved.