Fig. 4: The pore size characterization and gas separation performances of 6FDA-TFDB-x CMS membranes.

a N2 adsorption isotherms of 6FDA-TFDB-x CMS membranes was obtained at 77 K. b Pore size distribution of 6FDA-TFDB-x CMS membranes from N2 adsorption. c CO2 permeability and CO2/CH4 selectivity of 6FDA-TFDB-x CMS membrane. d O2 permeability and O2/N2 selectivity of 6FDA-TFDB-x CMS membrane. e The latest 2019 upper bound of CO2/CH4, f the latest of 2015 upper bound of O2/N2. The error bars in c and d represent standard deviation.