Methodology for Fabricating and Testing Carbon Molecular Sieve (CMS) Dense Film Membranes for Reproducible Permeation Experiments
Year: 2026
Type: preprint
Abstract: Carbon molecular sieve (CMS) membranes are promising for demanding gas separations, but their brittleness after pyrolysis makes dense-film permeation testing difficult and often irreproducible. Membranes that appear defect-free after pyrolysis can crack during handling, masking, permeation cell assembly, vacuum evacuation or gas pressurization. This work presents a practical procedure for fabricating and testing CMS dense films prepared from fluorinated polyimide-based CMS membranes. We investigated several experimental factors such as polymer concentration, membrane casting in glove bag, epoxy selection, filter paper support, masking and pressure loading, and their resulting impact on the mechanical stability of the membranes Careful control of these steps reduced or entirely mitigated film cracking, gas bypass during testing, and epoxy seal failure during permeation measurements. This study provides a reliable method for casting, masking and testing of fragile CMS dense film membranes and addresses practical details that are often not reported, but are important for successful and reproducible gas permeation data with CMS membranes.
Source: ChemRxiv
Institution: West Virginia University
Language: English
Subfield: Filtration and Separation
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7222029504