Femtosecond study of ultrafast fluorescence resonance energy transfer in a catanionic vesicle

Ultrafast fluorescence resonance energy transfer (FRET) in a catanionic sodium dodecyl sulfate (SDS)-dodecyltrimethyl ammonium bromide (DTAB)] vesicle is studied by femtosecond up-conversion. The vesicles (diameter ～400 nm for SDS-rich and ～250 nm for DTAB-rich vesicles) are much larger than the SDS and DTAB micelles (diameter ～4 nm). In both micelle and vesicles, FRET occurs in multiple time scales and the time scales of FRET correspond to a donor-acceptor distance varying between 12 and 36 A?.