SOLUBILIZATION AND RELEASE OF HYDROPHOBIC COMPOUNDS FROM BLOCK-COPOLYMER MICELLES - I - PARTITIONING OF PYRENE BETWEEN POLYELECTROLYTE MICELLES AND THE AQUEOUS-PHASE

Partitioning of pyrene between ly(tert-butylacrylate)-block-poly(2-vin ylpyridine) and polystyrene-block-poly(methacrylic acid) micelles and aqueous solvent has been studied by fluorometric techniques. The parti tion coefficient was evaluated on the basis of the steady-state fluore scence spectra and the time-resolved fluorescence decays from a series of solutions with decreasing copolymer concentrations, and the obtain ed values were compared. The agreement is very good. In the accompanyi ng paper, the release kinetics of pyrene from micelles upon a sudden a nd prodigious dilution of micellar solution by the aqueous solvent was studied by time-dependent measurements of the steady-state fluorescen ce intensity. Simultaneous mathematical treatment of dilution curves i n the absence and presence of water-soluble quencher based on the mode l of diffusion from a sphere allows the diffusion coefficient of pyren e in micellar cores to be evaluated. The assumption that micelles do n ot reorganize upon the shock dilution is tested by an independent expe riment.