Clustering of Aerosol OT Reversed Micelles As Studied by Nonradiative Energy Transfer of Solubilized Probes

Water-soluble anionic fluorescent molecules tetrasodium 1,3,6,8-pyrenetetrasulfonate (PyTS) and trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate (pyranine) were solubilized in separate reversed micellar cores in AOT/ n -heptane system. The reversed micelle system showed an extent of nonradiative energy transfer from PyTS to pyranine higher than for the aqueous solution system in comparison at a critical probe concentration, [P] C . The values of [P] C, where each micelle is occupied by statistically one probe molecule, were determined as a probe concentration where the solubilized disodium 2,6-naphthalenedisulfonate (NpDS) begins to show the intramicellar excimer fluorescence. The results reveal that at surfactant concentrations higher than 0.1 M the AOT reversed micelles are not randomly dispersed in isolated state in n -heptane but form clusters through intermicellar flocculation.