An absorption and fluorescence spectral study on the solubilization behavior of 2-[(p-methylamino)phenyl]-3,3-dimethyl-5-carboethoxy-3H-indole (I) in sodiumdodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) aqueous micelles and dioctadecyldimethylammonium bromide (DODAB) surfactant vesicles has been carried out. Using spectral correlations with the polarity parameters, polarity values corresponding to a dielectric constant D of 48, 33 and 36 have been estimated for SDS, CTAB and DODAB respectively at 298 K. The nature of the binding site has been discussed. In DODAB vesicles, the probe moves in average toward the center of the bilayer as a function of temperature. This behavior of molecule I in DODAB has been effectively used to discuss its permeability to external solubilizates. Fluorescence decay time analysis has been used to discuss the molecular recognition in these surfactant assemblies. pH effects on the ring nitrogen protonation (neutral-monocation equilibrium) have been carried out and the extent of monocation formation has been discussed on the basis of the charge nature of surfactant organized assemblies. © 1995.
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