Application of free-volume theory to self diffusion of solvents in polymers below the glass transition temperature: A review

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 49; no. 23; pp. 1629 - 1644
• Main Authors: Ramesh, N., Davis, P. K., Zielinski, J. M., Danner, R. P., Duda, J. L.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.12.2011; Wiley
• Subjects: Applied sciences; Computer simulation; Diffusion; Exact sciences and technology; free volume; glass transition; Glassy; Mathematical models; Miscellaneous; Molecular dynamics; Organic polymers; Physicochemistry of polymers; Polymers; Properties and characterization; Self diffusion; Solvents; diffusion; free volume; Transport properties; Computer simulation; Molecular dynamics method; Polymer; Review; polymers; glass transition; Solvent; Molecule scattering
• ISSN: 0887-6266; 1099-0488; 1099-0488
• DOI: 10.1002/polb.22366

Theories based on free‐volume concepts have been developed to characterize the self and mutual‐diffusion coefficients of low molecular weight penetrants in rubbery and glassy polymer‐solvent systems. These theories are applicable over wide ranges of temperature and concentration. The capability of free‐volume theory to describe solvent diffusion in glassy polymers is reviewed in this article. Two alternative free‐volume based approaches used to evaluate solvent self‐diffusion coefficients in glassy polymer‐solvent systems are compared in terms of their differences and applicability. The models can correlate/predict temperature and concentration dependencies of the solvent diffusion coefficient. With the appropriate accompanying thermodynamic factors they can be used to model concentration profiles in mutual diffusion processes that are Fickian such as drying of coatings. The free‐volume methodology has been found to be consistent with molecular dynamics simulations. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 Free‐volume models are frequently used to correlate and predict the self and mutual‐diffusion coefficients of low molecular weight solvents in rubbery and glassy polymer systems. Special considerations are necessary for diffusion in polymers below their glass transition temperature. The capability of free‐volume theory to describe this case is reviewed in this article. The models can correlate/predict temperature and concentration dependencies of the solvent diffusion coefficients over wide ranges of temperature and concentration.