This work has been focused on the electrospinning generation of nanofibrous membranes from polystyrene and polyurethane, and on sandwich membranes composed of these two polymeric components, on their structural characterization and finally on the evaluation of their gas transport behaviour. These tests were based on the isothermal counter-current gas diffusion measurements in the Graham's diffusion cell. It was shown that the transport characteristics (the net diffusion molar flux densities) can be utilized for the control of the electrospinning process homogeneity of the prepared membranes and their diffusion resistance. (C) 2010 Elsevier B.V. All rights reserved.