The purpose of this study has been to develop new proton-exchange membranes based on semi-interpenetrating polymer network (semi-IPN) architectures for application in polymer electrolyte fuel cells. A series of semi-IPNs combining a fluorinated hexane network and a linear sulfonated poly(aryl ether ether ketone) (SPEEK) has been obtained by varying the SPEEK content from 50 to 80 wt.%. A telechelic functionalized acrylate oligomer was obtained by acrylation of alpha,omega-fluorinated hexanediol, while SPEEK was synthesized by polycondensation of sulfonated difluorobenzophenone with the bisphenol 6F. These semi-IPN membranes have been characterized by infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and small-angle X-ray scattering. A semi-IPN containing 60 wt.% SPEEK has been tested as a fuel cell membrane. (C) 2011 Elsevier B.V. All rights reserved.