Surface modification of highly gas permeable membrane by nanosheets composed of ionic-functionalized polyimides

Abstract

Novel diamine monomers containing imidazolium or pyridinium groups were synthesized to prepare ionic polyimides, which were expected to have the affinity with CO 2 gases. Then, the nanosheets of these polyimides, the thickness of which were 50 -90 nm, were fabricated by spin coating method. Furthermore, the nanosheet-coating of polydimethylsiloxane graft copolyimide membranes was carried out, and the effect of surface structure on the gas permselectivity was investigated. As a result, the nanosheet coating on the highly gas permeable membrane was effective to improve the selectivity of CO 2 /N 2 and O 2 /N 2 with maintaining the high gas permeability to some extent. In addition, it was found that the gas separation properties depended on the side chain structures of polyimides containing ionic groups.Trans. Mat. Res. Soc. Japan 43[5] 279-282 (2018)