Solubilization and release of hydrophobic compounds from block copolymer micelles. II. Release of pyrene from polyelectrolyte micelles under equilibrium conditions

Abstract

The kinetics of the release of pyrene from poly(tert-butyl acrylate)-block-poly(2-vinylpyridine) polyelectrolyte micelles into aqueous media was studied by two independent experimental fluorometric techniques. Mathematical treatment of the time-dependent fluorescence intensities based on a model of diffusion from a sphere allowed the evaluation of the diffusion coefficient of pyrene in the dense poly(tert-butyl acrylate) micellar core. Assumptions necessary for mathematical treatment of experimental curves were tested and their validity was proved. Fluorometric measurements suggest that a considerable fraction of pyrene is solubilized also in poly(2-vinylpyridine) micellar shells.