Title: DIFFUSION IN POLYMER FILMS WITH LANGMUIR ADSORPTION AND PARTIAL IMMOBILIZATION
Abstract: Sorption of several solute-polymer systems can be characterized by a combination of Henry's law sorption and Langmuir adsorption. The sorbate in the Langmuir adsorption is assumed to have different diffusivity compared to the sorbate in Henry's sorption. The concentration distribution and mass uptake of a polymer film subject to a step increase of sorbate at the surface were solved by the Crank-Nicholson method. With a smaller value of diffusivity for the Langmuir adsorbed molecules the normalized concentration distribution and mass uptake increased more slowly than the corresponding sorption without the Langmuir adsorption. The mass uptake after a step increase of the sorbate concentration is proportional to at the beginning stage of sorption. From the parameters of sorption isotherms and the initial slopes of normalized mass uptake vs. plots the diffusivities of both Henry's law sorption and Langmuir adsorption species can be determined.
Publication Year: 2004
Publication Date: 2004-05-01
Language: en
Type: article
Indexed In: ['crossref']
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