Structural and hydrodynamic characteristics of polysulfone-polyaniline-type membranes (Psf-PANI) are depending on a number of parameters. The present article details the influence upon such membrane of the characteristics of obtaining process, type of monomer used in generating the composite membrane and pH of the solution permeating the membranes (for flow characterization). Membranes were obtained in a steady-state process, using an inversion phase technique accompanied by an in situ chemical reaction. The composite character of the material is a result of inserting, in the pre-existing porous polymer structure (polysulfone, Psf) of a second monomer (aniline or substituted anilines, e. g., amino-benzoic acid, 3ABA) through an oxidative polycondensation reaction. The steady-state process ensures a constant and reproducible structure of the composite material. As the study shows, from the two types of obtained composite membranes, the one that uses aniline polycondensation on polysulfone substrate presents better performances, compared with the one that uses substituted aniline in polycondensation (Psf-P3ABA). (C) 2013 Society of Plastics Engineers