A three-phase polymer/liquid/solid poly(amide-b-ethylene oxide) (PEBA)/polyethylene glycol (PEG)/zeolite X was fabricated and its gas permeability was investigated. CH4 permeability of neat PEBA, two-phase PEBA/NaX and three-phase PEBA/PEG/NaX were compared for different pressures within the range of 2-8 bar. The fabricated membranes were structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscope (AFM). SEM images showed that the zeolite grain size was homogeneously smaller than 2 mu m. They also revealed the dense structures of the membranes and no pores were observed at these magnifications. AFM surface images indicated that the membranes surface roughness increased significantly with increasing zeolite loading. CH4 permeability for single-, two-and three-phase membranes decreased from 3.13 to 2.81, from 3.96 to 2.31 and from 2.67 to 2.14 barrer, respectively. (C) 2014 Elsevier B.V. All rights reserved.