Asymmetric MMMs were fabricated containing various amount of organically modified clay particle (Cloisite (R) 15A) with the main intention to investigate the gas permeation behavior of the resultant material combination. The fabricated MMMs were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM) and pure gas permeation testing. XRD analysis suggested that clay layers crystalline structure was slightly changed upon blending but only limited polymer chain intercalation occurred thus resulted in phase separated clay-polymer composite. The gas permeation properties were evaluated by pure gases: nitrogen, oxygen, methane, and carbon dioxide. The gas permeation rate was observed to be increasing with increasing clay content while the selectivity remained at par to that of unfilled PSF before it declined at 2 wt.% C15A loading due to filler agglomeration as confirmed by FESEM. The best results were obtained at 1 wt.% C15A loading where more than 270% enhancement in O-2 and CO2 permeance were observed, with insignificant change in O-2/N-2 and CO2/CH4 selectivity compared to that of neat PSF. (C) 2013 Elsevier B.V. All rights reserved.