Comparison of dissolution and mutual diffusion coefficients during dissolution of poly(methyl methacrylate) films

Steady state fluorescence measurements have been used for studying the dissolution of polymer films. These films are formed by free radical polymerization of methyl methacrylate (MMA) in which pyrene (<(P-y)over bar>) was introduced as a fluorescence probe. Dissolution of poly(methyl methacrylate) (PMMA) films in chloroform-heptane mixtures were monitored in real-time by the <(P-y)over bar> fluorescence intensity change. Dissolution coefficients D-d of P-y molecules were measured during dissolution of PMMA films, and found to be about 10(-6)cm(2)s(-1). After dissolution, fluorescence quenching measurements were performed and the Stern-Volmer equation was employed to measure the mutual diffusion coefficients of heptane (D-h) and <(P-y)over bar> (D-Py) molecules; these were found to be about 10(-5) cm(2) s(-1). (C) 1999 Society of Chemical Industry.