Fabrication of polymer-polymer nanocomposites based on sub-micron electrospun fibers imbedded in a distinct matrix is dependent on being able to control the wetting behavior of the electrospun fibrous mats. In this work the use of radiation grafting to modify electrospun polysulfone fiber surfaces with acrylamide is presented. Pre-irradiation grafting using electron beam (EB) and plasma treatments have been evaluated. The grafted fibrous mats were characterized using contact angle measurements, XPS, ATR-FTIR, and ESEM. It was found that 3 MeV EB can be used to obtain controlled degrees of grafting by varying total dose and that such grafting is uniform throughout the thickness of the fiber mat. In contrast, plasma grafting resulted in a concentration gradient of grafted acrylamide through the thickness with highest grafting yield on the surface of the mat exposed directly to the plasma. Procedures based on these techniques can be employed to generate polymer-polymer nanocomposites of dissimilar materials with geometric characteristics derived from the templating material. (c) 2005 Elsevier B.V. All rights reserved.