On the Spectral Behavior of an Ionic Styryl Dye: Effect of Micelle-Polyethylene-block-polyethylene Glycol Diblock Copolymer Assembly

The interaction of anionic micelle sodium dodecyl sulfate (SDS) and amphiphilic block copolymers polyethylene-b-polyethylene glycol (PE-b-PEG) and the sharp change of excited-state charge-transfer complex photophysics of 2-(4-(dimethylamino)styryl)-1-methylpyridinium iodide (DASPMI) inside of the supramolecular assembly have been addressed in the paper. The dramatic enhancement of emission intensity of DASPMI incorporated inside of the nanostructure formed by micellar and polymeric chains indicates a completely different environment compared to that in the water and micellar system. A huge increase in the rotational relaxation time obtained from time-resolved anisotropy decay and the value of the order parameter is indicative of a very restrictive regime in the self-assembly system. The wobbling and translational motion of the probe is also restricted inside of the micelle-polymer aggregate due to the presence of polymer chains. The translational diffusion coefficient is drastically reduced due to the aggregation.