In the present investigation, polysulfone (PSu) nanocomposites were successfully prepared by solvent casting method. Layered silicates, viz., sodium montmorillonite (NaMMT), Cloisite 93A, and Cloisite 30B were dispersed in PSu to obtain nanocomposite membranes. PSu nanocomposite membranes were tested for mechanical performance, water uptake, thermal properties, X-ray diffraction, and scanning electron microscopy (SEM). The nanocomposite membranes showed an increment in tensile properties, whereas a reduction was observed in water uptake. X-ray diffraction studies confirmed the intercalation of PSu within the silicate galleries. SEM analysis confirmed an increase in the porosity of the membrane with the incorporation of nanoclays. Thermo gravimetric analysis (TGA) thermograms indicated an increase in the thermal stability of PSu nanocomposites. Evaluation of conductivity characteristics and single cell performance revealed improved output for organomodified clay nanocomposites. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012