DIFFUSION OF SMALL MOLECULE MATTERS IN POLY(VINYL ALCOHOL)-WATER GELS

The diffusion of ethanol, urea, glucose and sucrose into gel beads which are prepared from the equeous solutios of poly(vinyl alcohol) (PVA) has been investigated. The diffusion coefficients of those small molecule matters in gel beads have much to do with temperauture and the free-water content and the pore size of the gels. The structure of gel beads, which determines the pore size of the gels, depends on the concentration of PVA gels, freezing time and preparation method of gel beads. The diffusion coefficients of the above mentioned matters in the gels increase with the rise of temperature, and do with their concentrations at given freezing time. The diffusion coefficient of sucrose in the gels decreases, but the diffusion coefficients of ethanol, urea and glucose increase, with the increase of freezing time at the given concentration.