The introduction of functionality into asymmetric polysulfone membranes has widened their applicability. They are modified with acrylic acid with a light-induced technique. Fourier transform infrared, contact-angle, porometry, and atomic force microscopy studies have been carried out to characterize the membranes. The performance of the modified membranes has been investigated with permeation measurements. The salt rejection (NaCl and Na2SO4) performance of the modified membranes shows evidence of functionalization on them. The modification of the membranes also develops the retention of small organic molecules (glucose and 2,4-dichlorophenol). (c) 2007 Wiley Periodicals, Inc.