Proton-conductive polyimides consisting of naphthalenediimide and sulfonated units alternately segmented by long aliphatic spacers

Sulfonated polyimides (SPIs) consisting of naphthalenediimide and sulfonated units alternately segmented by long aliphatic spacers have been facilely synthesized. Such an unprecedented molecular design of SPIs avoiding conventional aromatic-type imide units allows the stacking of naphthalenediimide moieties and aggregation of sulfonate groups simultaneously, imparting high conductivity and excellent hydrolytic stability.