Explain the diffusion in solid through polymer
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Sorption of vapors in polymer membranes in the vicinity of and below the glass transition temperatures do not follow the Fickian (classical) diffusion. The reasons have been attributed to the molecular relaxation which affects both diffusivities and solubilities.
A time- and memory-dependent diffusion coefficient has been evaluated in Part I, in a form which is analogous to the treatment in the rheology of such materials. Together with a time-dependent solubility, the conservation equation for the sorption process has been solved. Two special cases are considered, where the relaxation times are short and where they are long. The results explain the anomalous behavior observed in the experiments. Comparison with the experiments has been made.
A time- and memory-dependent diffusion coefficient has been evaluated in Part I, in a form which is analogous to the treatment in the rheology of such materials. Together with a time-dependent solubility, the conservation equation for the sorption process has been solved. Two special cases are considered, where the relaxation times are short and where they are long. The results explain the anomalous behavior observed in the experiments. Comparison with the experiments has been made.
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