POLY(METHYL METHACRYLATE) FILM DISSOLUTION AND SOLVENT DIFFUSION-COEFFICIENTS - CORRELATIONS DETERMINED USING LASER INTERFEROMETRY-FLUORESCENCE QUENCHING AND PULSED-GRADIENT SPIN-ECHO NMR-SPECTROSCOPY

We correlate the results of pulsed-gradient spin-echo (PGSE) nuclear m agnetic resonance (NMR) measurements of solvent self-diffusion coeffic ients in binary poly(methyl methacrylate) (PMMA) mixtures with laser i nterferometry-fluorescence quenching (LIFQ) measurements of PMMA film dissolution for a series of identical ketone and ester solvents. Withi n a homologous solvent series, the self-diffusion coefficients as well as film dissolution rates decrease in tandem with increasing solvent molecular size and cross-section. When self-diffusion coefficients are compared, little difference is found between esters and ketones of no mially identical molecular size. However, systematic differences in fi lm dissolution rates are evident when comparing ketone and ester solve nts. These differences are eliminated when film dissolution rates for esters and ketones are compared on the basis of the solvent free volum e parameters extracted from the PGSE NMR self-diffusion coefficient da ta using Fujita's free volume theory.