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

摘要: A nondestructive technique is presented for in-situ analysis of solvent induced membrane swelling. The based on spectroscopic ellipsometry (SE) and allows simultaneous measurement film thickness sorption. attainable experimental conditions are only limited by the test cell (≤473.15 K, ≤20 MPa) far exceed those encountered in typical resistant nanofiltration (SRNF) applications. influence cross-linker concentration swelling thin films bulk samples poly(dimethyl siloxane) (PDMS) resolved interaction parameters according to Flory–Huggins Flory–Rehner theories calculated. It found that due confinement support supported a correction elastic deformation network necessary. In pressurized swollen refractive index be independent pressure range 0.1–10 MPa suggesting molar volumes penetrant liquid sorbed phases not significantly different. When difference over applied allowed permeate, progressing reduction observed with increasing upstream pressure. derived concentrations n-hexane at interface between support, permeate side, excellent agreement values calculated using solution–diffusion model. This implies quantification contribution mixed mode transport, instance occurring simultaneously pore-flow transport through defects, composite membranes.