New proton-conducting co-networks were synthesized, characterized and tested as Polymer Exchange Membranes for Fuel Cells application. The membranes were obtained from 2-acrylamido-2-methylpropane sulfonic acid (AMPS) copolymerized with a perfluoropolyether oligomer used as crosslinker (Fluorolink (R) FMD700). The structure, the thermo-mechanical behavior, the transport properties and the stability were examined in function of the co-network composition, e.g. increasing amount of conductive AMPS. High proton conductivity (1.10(-3)-5.10(-3) S cm(-1)) was reached at a threshold composition of 10 wt% AMPS, which also corresponds to a significant increase in water sorption. The efficiency of proton transfer was shown to directly correlate to the phase-separated nanostructures. On increasing the AMPS content, hydrophilic clusters embedded in the mechanically-robust FMD700 percolate and a co-continuous 3D morphology is formed. Fuel cells tests performed using the high-AMPS content crosslinked membranes showed behaviors comparable to benchmark Nafion (R) under similar conditions, with performances significantly improved when the temperature is increased.