SIMULTANEOUS MEASUREMENT OF WATER AND POLYMER CONCENTRATION PROFILES DURING SWELLING OF POLY(ETHYLENE OXIDE) USING MAGNETIC-RESONANCE-IMAGING

A one-dimensional, slice-selective magnetic resonance imaging (MRI) te chnique is used to image in situ the penetration of water into poly(et hylene oxide) (PEG). Spin-lattice relaxation time (T-1)-weighted imagi ng experiments provide simultaneous, quantitative measurements of poly mer and water concentration profiles, penetrant front motion kinetics and swelling kinetics. The propagation of the penetrant front is obser ved to be a diffusion-controlled process, with no volume change on mix ing during swelling. Excellent agreement is observed when comparing th e polymer concentration profiles obtained from the T-1 analysis with t hose measured by H-1 imaging of PEO during penetration by D2O, under w hich conditions only the polymer response is imaged. (C) 1997 Elsevier Science Ltd.