SOLVATION DYNAMICS IN ORGANIZED ASSEMBLIES - 4-AMINOPHTHALIMIDE IN MICELLES

Solvation dynamics of 4-aminophthalimide (4-AP) has been studied in ne utral (triton X-100, TX), cationic (cetyl trimethyl ammonium bromide, CTAB) and anionic (sodium dodecyl sulfate, SDS) micelles using picosec ond time resolved Stokes shift. Above critical micellar concentration (CMC), fbr all the three micelles, 4-AP exhibits wavelength dependent fluorescence decays with a fast decay at the blue end and a slow decay accompanied by a distinct growth at the red end of the emission spect ra. The time dependent Stokes shift indicates that the water molecules in the Stern layer of the micelles relax in approximate to 100 ps tim e scale which is markedly slower than the subpicosecond relaxation dyn amics observed in ordinary bulk water. (C) 1998 Elsevier Science B.V.