A series of sulfonated random copolyamides with increasing sulfonation degree were synthesized from the aromatic diamine 4,4'-(hexafluoroisopropylidene)dianiline, HFA, reacted with 2,4-diaminobenzenosulfonic acid, DABS, by direct polycondensation using isophthalic diacid, ISO, as comonomer. Thin films of the sulfonated copolyamides were prepared by the solution-evaporation method using dimethylacetamide, DMAc. The structure of the resulting sulfonated copolyamides was confirmed by FTIR and H-1 NMR which evidenced the presence of amide and sulfonic groups in the proposed concentrations. Thermal stabilities as characterized by TGA, showed the onset of decomposition at 320 degrees C for the ionic moieties and above 600 degrees C for the nonsulfonated part of the copolymers. The values of water uptake and ion exchange capacity, IEC, at room temperature for the copolymer with 50 mol % of DABS, HFAS55 membrane were higher than those obtained for Nafion 115. HFAS55 also presented a proton conductivity value of 3.3 (mS cm(-1)) which was similar to the one of Nafion 115 tested under the same conditions which situates it as a possible material for PEM membrane preparation.