Reverse Micelles of Triton X-100 in Mixed Solvents of Benzene and N-Hexane : Fluorescence Studies Using 7-Hydroxy Flavone as a Probe

7-Hydroxyflavone (7HF), has been used as a fluorescence probe to investigate the microenvironments and water distribution in Triton X-100 (TX-100) reverse micelles in benzene/n- hexane mixed solvents at different water/surfactant molar ratio (w0). Upon variation of w0, the green fluorescence emission of 7 HF shows dramatic spectral shifts, with the emission maximum (λmaxem) varying from λmaxem = 527 nm at w0 = 0, to λmaxem = 552 nm at w0 = 9. Variation of w0 over this range also leads to a significant increase in the fluorescence polarisation anisotropy (FPA). These results are interpreted in terms of changes in the local environment of the fluorophore. It is also evident that the formation of bulk water starts at w0 = 2.5 in the TX-100/benzene/n-hexane reverse micelles, in agreement with the absorption probe studies.