Studies on aggregation of AOT and NaDEHP via the energy transfer between AO and RB molecules

The aggregation behaviours of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP) solutions are studied via the energy transfer of acridine orange (AO) and rhodamine B(RB) molecules. The approximate apparent energy transfer efficiency (phi(a)) of the dye molecules reaches its maximum value when the concentrations of AOT and NaDEHP are far lower than their cmc. This might be caused by the formation of surfactant-dye mixtures. The anionic surfactants (SDS, AS. AOT and NaDHEP), cationic surfactant (CTAB) and nonionic surfactant (Triton-X-100) are chosen to investigate the effect of the structure of surfactant on the phi(a) between AO and RB molecules. The results indicate that the effective energy transfer may occur in the anionic surfactant systems and it is not obvious in the nonionic and cationic surfactant systems. (c) 2005 Elsevier Ltd. All rights reserved.