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Permeation of CO 2 and N 2 through glassy poly(dimethyl phenylene) oxide under steady‐ and presteady‐state conditions
Author(s) -
Soniat Marielle,
Tesfaye Meron,
Mafi Amirhossein,
Brooks Daniel J.,
Humphrey Nicholas D.,
Weng LienChun,
Merinov Boris,
Goddard William A.,
Weber Adam Z.,
Houle Frances A.
Publication year - 2020
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20200053
Subject(s) - permeation , phenylene , diffusion , polymer , sorption , oxide , materials science , steady state (chemistry) , chemistry , membrane , thermodynamics , analytical chemistry (journal) , organic chemistry , biochemistry , physics , adsorption
Glassy polymers are often used for gas separations because of their high selectivity. Although the dual‐mode permeation model correctly fits their sorption and permeation isotherms, its physical interpretation is disputed, and it does not describe permeation far from steady state, a condition expected when separations involve intermittent renewable energy sources. To develop a more comprehensive permeation model, we combine experiment, molecular dynamics, and multiscale reaction–diffusion modeling to characterize the time‐dependent permeation of N 2 and CO 2 through a glassy poly(dimethyl phenylene oxide) membrane, a model system. Simulations of experimental time‐dependent permeation data for both gases in the presteady‐state and steady‐state regimes show that both single‐ and dual‐mode reaction–diffusion models reproduce the experimental observations, and that sorbed gas concentrations lag the external pressure rise. The results point to environment‐sensitive diffusion coefficients as a vital characteristic of transport in glassy polymers.