Real-time monitoring of swelling and dissolution of poly(methyl methacrylate) discs using fluorescence probes

A new technique, based on steady state fluorescence measurements is introduced for studying swelling and dissolution of polymer discs. These discs are formed by free radical polymerization of methyl methacrylate (MMA). Pyrene (Py) was introduced as a fluorescence probe during polymerization. Swelling and dissolution of disc shape poly(methyl methacrylate) (PMMA) samples in chloroform-heptane mixtures were monitored in real-time by the Py fluorescence intensity change. The effects of solvent quality and agitation (stirring) on film dissolution were studied. Sorption and desorption coefficients of solvent and Py molecules were measured respectively during dissolution of films, and found to be between 10^-7 and 10^-6cm²s^-1.