As a new solvent free method for membrane formation, we have investigated the foaming of high-Tg polymers. We report two different routes for the formation of open-microcellular and open-nanoporous membrane morphologies. Porosity is introduced by expansion of carbon dioxide saturated films and hollow fibers at elevated temperatures. The microcellular structure manifests itself by small spot-like openings with diameters between 50 and 200 nm in the cell walls. The nanoporous structures exhibit a lacy structure with pore sizes between 2 and 50 nm. The mass transport resistance of the membrane structures is characterized in detail on the basis of gas permeation measurements.
- Carbon dioxide
- Glassy polymers
Krause, B., van der Vegt, N. F. A., & Wessling, M. (2002). New ways to produce porous polymeric membranes by carbon dioxide foaming. Desalination, 144(1-3), 5-7. https://doi.org/10.1016/S0011-9164(02)00280-1