Visible and fluorescence spectroscopic studies on interaction of water-soluble anionic azo dyes with Triton X-100 in reverse micelle media

A series of Triton X-100 (TX-100) reverse micelles was prepared in isooctane and characterized with respect to size, polarity, and electric conductivity. Three typical azo dyes including methyl orange (MO), Acid Black 234 (AB 234) and Reactive Red 195 (RR 195) were selected and solubilized in the water phase to investigate their interaction with TX-100 reverse micelles. Effect of water content on the spectra of these dyes in the micelles was also examined. It has been revealed from the experimental results that at low water content, MO and AB 234 may be located in the polar core but outside the water pool of the micelles. Increasing water content leads to their gradual movement towards the water pools. AB 234 may bind to the micelles more closely than MO, especially at high water content. Moreover, the stronger interaction between RR 195 and TX-100 result in the complex formation. Higher water content enhances the transition from bound RR 195 to free RR 195. It can be concluded that the spectral characteristics of the three dyes in the micelles are very different owing to the space limitation and the polarity evolution of the microenvironment of the micelles.