This study aims at the effect of electro-osmotic flow on a fibrous membrane comprised of assembled oppositely-charged polyelectrolytes and submerged in aqueous ionic solution. As electric field is applied across an edge-clamped circular membrane, it deforms under the action of a transverse force, the origin of which is in focus. Fibers were electrospun from a blend of poly(allylamine hydrochloride)/poly(acrylic acid) (PAH/PAA). A model is presented, which explains and describes the membrane deformation in terms of the ionic strength and pH level of the solution, the membrane geometry and porosity, the xi-potential and elastic modulus of the membrane, as well as the applied cross-membrane electric potential difference. The model is corroborated by a set of experiments. The dependence of the membrane deformation on the electric potential was found to be rather weak, while the elastic modulus was found to be strongly dependent on the solution pH.