PIM-1-based freestanding mixed matrix membranes (MMMs) and thin film nanocomposites (TFNs) were prepared by incorporating porous silica nanosheets (SN) exfoliated SN (E-SN) derived from natural vermiculite (Verm) in the PIM-1 polymer matrix. In addition, functionalized sulfonic acid amine groups (S-SN N-SN, respectively) also used as fillers for preparation of MMMs. The gas separation performan...