The Interaction Of Homodimer Styrylcyanine Dyes With Sodium Dodecyl Sulfate And Triton X-100

Solubilization of the styrylcyanine dye Sbt ((E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]thiazol-3-ium iodide) and its homodimers Dbt-5 and Dbt-10 in aqueous solution of sodium dodecyl sulfate and Triton X-100 has been studied by steady state and picosecond time-resolved fluorescence spectroscopy. At low concentration of sodium dodecyl sulfate in solution, between Sbt, Dbt-5 dyes molecules and surfactant ion pairs are formed followed by the formation non-luminescent H-aggregates. The nature of the interaction between molecules of dyes and surfactants has been revealed. The binding constants Ks of the dyes to the surfactants, free energy changes (Delta G0), the number of dye molecules (n) included in a single micelle and photophysical parameters have been determined. The degree of solubilization of dyes in micellar solution of Triton X-100 is higher as compared to sodium dodecyl sulfate and depends on the molecular weight and size of both dye molecules and micelles.