n-Hexane induced swelling of thin PDMS films under non-equilibrium nanofiltration permeation conditions, resolved by spectroscopic ellipsometry

► Quantitative in-situ study of membrane swelling under permeation conditions. ► Experimental confirmation and quantification of mass transport via solution-diffusion. ► Evidence for similar molar volume of n-hexane, as pure liquid and sorbed in PDMS. ► Elucidation of cross-linker content influence on swelling of thin and bulk PDMS films.