EXIT AND REENTRY KINETICS OF BROMOACETONAPHTHONE IN AQUEOUS POLYSTYRENE POLY(ETHYLENE OXIDE) BLOCK COPOLYMER MICELLES

Phosphorescene quenching kinetic, were studied for 4-bromo-1-acetonaph thone (BAN) in water in the presence of a series of polystyrene-poly(e thylene oxide) block copolymer micelles. The quencher, NaNO2, remains in the aqueous phase. We determine the exit and entry rate constants f or BAN and the micelles: the former rate constant is independent of th e micelle size whereas the latter increases linearly with the micelle core radius. These experiments demonstrate that BAN binds only to the surface region of the micelle where it is protected from quenching. Un der our experimental conditions, we can establish that whenever BAN3 exits from a micelle, it essentially always reenters the same micelle.