Polyaromatic ionomers with a highly hydrophobic backbone and perfluorosulfonic acids for PEMFC

•Substitution of the polymer backbone with perfluorosulfonic acid in one step.•Design of ionomers with very hydrophobic backbone.•The ionomers show better proton conducting properties than the Nafion.•The ionomers show moderate water uptake even at high ion exchange capacity.

The publication reports, for the first time, on the synthesis of aromatic-based ionomers bearing superacid side groups bonded to a highly hydrophobic fluorinated aromatic backbone. The incorporation of the side group on the backbone takes place in one step via a nucleophilic substitution. The membranes obtained from these new ionomers show phase separation at nanoscale and moderate water uptake even at high ion exchange capacity (IEC), i.e. 1.7 meq/g. Additionally, their conductivity and mechanical strength are much higher than those of the benchmarked ionomer Nafion®, which makes them very promising materials for fuel cell application.

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