Fluorescence anisotropy decay in polymer-surfactant aggregates

The fluorescence anisotropy decay of two dyes merocyanine 540 and oxazine 1 has been studied in a polymer-surfactant aggregate containing poly(vinylpy rrolidone) (PVP) and sodium dodecyl sulfate (SDS). The results are analyzed in terms of the necklace model of the polymer-surfactant aggregate. The ro tational motion of the probe is assumed to involve "wobbling-in-cone" along with translational motion along the micellar surface. It is observed that the presence of the polymer chains around the spherical SDS micelles causes significant retardation of both the wobbling motion as well as the transla tional motion of the two dyes. As a result, the wobbling and translational diffusion of the dyes in the PVP-SDS aggregate are slower than those in SDS micelle.