Résumé
Grafting of sulfonated aryl groups on to polybenzimidazole, PBI, leads to a proton conducting polymer. The synthetic route allows close control of the degree of sulfonation, and a range of samples have been prepared with degrees of sulfonation up to 75% of the available sites. Sulfonation increases the conductivity from ca. 10
−4 S
cm
−1 in non-modified PBI to >10
−2 S
cm
−1 at room temperature for highly sulfonated samples. The dependence of the conductivity both on the degree of sulfonation and on the conditions of membrane preparation are discussed.