Absorption and emission spectroscopic studies of fluorescein dye in alkanol, micellar and microemulsion media

The photophysical behaviours of the dye fluorescein have been studied in alkanols (methanol to decanol), in micellar solutions of SDS, CTAB and Triton X-100 and in the w/o microemulsion system of water/AOT/heptane. The alkanols are found to affect the absorption and fluorescence spectra of the dye. On the basis of the solvent adsorption model the binding constants of the dye with the alkanols have been estimated. The absorption and emission spectra of the dye are observed to be influenced by the ionic surfactants SDS, CTAB and not influenced by the non-ionic representative Triton X-100. The results confirm formation of a 1:1 complex of the dye with SDS and CTAB micelles. In the w/o microemulsion medium, the photophysical behaviours of the dye are found to be different from non-aqueous and micellar media. (C) 1999 Elsevier Science S.A. All rights reserved.