Experimental determination of self-diffusivities through a polymer network for single components in a mixture

Diffusion models such as Vrentas & Duda diffusion theory and Wesselingh & Bollen multicomponent diffusion model have been used together with estimated tracer diffusion coefficients in order to provide a predictive method to calculate thermodynamic diffusion coefficients needed for transport simulation in polymer membrane processes. PFG-NMR measurements were carried out in order to estimate the tracer diffusion coefficients for solvent–solvent–polymer systems on free-standing crosslinked polymer films. The use of experimentally determined diffusivities for a set of finite solvent-solvent-polymer concentrations as well as of plausible assumptions in nanofiltration allows the estimation of the unclear parameters presented in the diffusion theories with the subsequent predictability for those systems.