Effect of a Drying Pretreatment on Morphology of Porous Poly(Ether-Imide) Membrane Prepared Using Vapor-Induced Phase Separation

Abstract

Symmetric porous membranes were prepared from concentrated poly(ether-imide) (PEI) solutions using vapor-induced phase separation (VIPS) coupled with a drying pretreatment. Moderately concentrated solutions of PEI in N-methylpyrrolidinone (NMP) (14–16 wt%) were first cast on glass plates and the solvent was then allowed to evaporate under a dry air flow up to the desired concentration (16–38 wt%) before forming the membrane structure by VIPS. The polymer concentration profiles (confocal Raman microscopy) and model predictions were in good agreement to show that the evaporation stage did not induce a polymer gradient concentration with PEI/NMP systems. These results were confirmed by examination of the final membrane morphology (SEM).

Keywords:

• Drying
• Polymer solution
• Polymeric porous membrane
• Vapor-induced phase separation

Notes

*Ns represents the mass ratio between NMP and PEI.