Drastic photostabilization and one way isomerization from cis- to trans-forms of 4,4`-diaminostilbene 2,2`-disulfonate fluorescent dyes, DAS-1, DAS-2, and DAS-3, were found in the micellar HDPC solution over the cmc. However, the addition of HDAB, SDS, and B-35 to the aqueous solutions of the dyes had no effect on stabilization. The fluorescence life times of DAS-1 in HDPC micelle were much longer than those in HDAB micelle and in the absence of surfactant. These results were interpreted in terms of energy transfer and back energy transfer in an encounter complex between the fluorescent dye molecule and the pyridinium ion moiety in HDPC micelle.
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