Fluorescence and energy transfer of dye-detergent systems in the premicellar region

Abstract

Abstract The fluorescence lifetimes of dyes and also the energy transfer between dyes with closely located S 1 levels were studied in the presence of detergents. These dye-detergent systems can be considered as one of the model membrane systems of chloroplasts and show some peculiar features when the detergent has the opposite charge to that of the dye. The energy transfer efficiency between rhodamine 6G (Rh-6G) and pinacyanol (PC) in the presence of sodium lauryl sulphate (SLS) showed a distinct peak in the premicellar region, i.e. for [SLS] a little less than the critical micelle concentration. A long dimer-like lifetime was observed in the acridine orange (AO)-SLS system in the premicellar region. These findings and the absorption and fluorescence spectra revealed that the dye molecules are associated with dye-rich induced micelles which reduce the average distance (AO-AO or Rh-6G-PC) between dye molecules in the premicellar region.