Highly porous PVDF membranes supported on non-woven polyester fabric were prepared by the phase inversion method from the solutions of different concentrations at identical conditions of casting as temperature, relative humidity and air drying time before immersion in non-solvent using motorized machine to study the microstructures formed in the resulting membrane and correlate membrane morphology to membrane performance in membrane distillation process. The membranes were extensively characterized for porosity, hydrophobicity and surface topography. Morphology study indicated an anisotropic nature of the membranes resulting from phase inversion occurred through liquid-liquid demixing process. The membrane prepared from casting solution of low polymer content is highly porous compared to those prepared from solution of higher polymer content. The membranes demonstrated potential for desalination from 30,000 to 100,000 ppm synthetic seawater through membrane distillation. The membranes exhibited 99.0+% salt rejection efficiency and varied water flux ranging from 2 to 121 center dot m(-2) center dot h(-1) (LMH) depending on the membrane pore structure feed concentration and processing parameters. All the membranes exhibited practically uniform performance in all feed concentration ranges which indicated that there is no adverse effect of increased salinity in the feed on the performance of the membrane. (C) 2014 Elsevier B.V. All rights reserved.