In this study, a total of eight membranes have been simulated: PIM-1, 12 PIM-7, 12 PIM-PI-1, 52 PIM-PI-8, 52 PIM-PI-9, 14 PIM-PI-10, 14 PIM-PI-11, 14 and 6FDA-TMDA, with their chemical structures presented in Fig. . PIM-based membranes are particularly noteworthy due to their extensive application in membrane gas separation, where they demonstrate exceptionally high permeability and good perm-selectivity. As a result, many of these membranes are positioned on or near the Robeson upper bound, making them the ideal candidates for further investigation.