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Magnetic Resonance Imaging Analysis Of Molecular Mobility During Dissolution Of Poly(Vinyl Alcohol) In Water, Balaji Narasimhan, J. E.M. Snaar, R. W. Bowtell, S. Morgan, C. D. Melia, N. A. Peppas

Balaji Narasimhan

Magnetic resonance imaging is used to study changing microstructure and molecular motion during dissolution of poly(vinyl alcohol) (PVA) in water. One-dimensional water concentration profiles were measured as a function of distance from the polymer-solvent interface. Diffusion-weighted profiles were used to calculate the spatial variation of the self-diffusion coefficient of water. The results indicate that diffusion coefficient values decrease toward the glassy core of the polymer. Self-diffusion coefficient values within the dissolving polymer increase with increasing dissolution time, while those near the polymer-solvent interface remain fairly constant. The effect of PVA molecular weight on the dissolution mechanism was investigated, with MÌ„n …