This work reports on the preparation and properties of polydimethylsiloxane (PDMS)/low-density polyethylene (LDPE) multilayer composite polymer membranes (MCPM) for gas separation applications. The membranes were produced by combining sequential coating with melt-extrusion/salt leaching techniques. In particular, the gas sorption and permeation properties at different pressure (40-90 psig) and temperature (27-55 degrees C) are reported with morphology and thermogravimetric properties. The results show that a 20 m PDMS layer was able to penetrate the microporous LDPE surface layer substrate leading to improved interfacial adhesion. Based on the different gases (CO2, CH4, and C3H8) solubility, permeability, and diffusivity obtained, these membranes are seen as good candidates for industrial gas separations. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1045-1052