Fluorescence probing of mixed reverse micelles formed with AOT and nonionic surfactants in n-heptane

The nature of the aqueous core of mixed reverse micelles formed with AOT and nonionic surfactants in n-heptane was investigated by fluorescence techniques. The emission properties of 1.8-anilinonaphthalenesulfonic acid (ANS) and tris (2,2'-bipyridine) ruthenium dichloride hexahydrate (Ru(bpy)(3)(2+)) were found to be extremely sensitive to the solubilized water content. The fluorescence intensity decreases with increasing water content while the position of the emission maximum lambda(max) shifts to longer wavelengths. The lambda(max) of the fluorescence probe also depends on the added nonionic surfactant content and their EO chain length. The microstructure of the waterpool and the effect of added nonionic surfactants were studied by the fluorescence analysis of the two fluorescence probes from the viewpoint of their different location in mixed reverse micelles. (C) 1998 Elsevier Science B.V. All rights reserved.