Soluble sulfonated naphthalenic polyimides as materials for proton exchange membranes

Series of sequenced sulfonated naphthalenic polyimides with improved solubi lity were prepared by polycondensation in m-cresol using aromatic diamines containing phenylether bonds and/or bulky groups. Sulfonated polyimides wer e characterized by NMR and IR spectroscopies. Membranes were prepared by so lution casting method and characterized by determining the ion-exchange cap acity, water swelling, proton conductivity whereas the morphology of polyme r membranes was studied by small angle neutron scattering. (C) 2000 Elsevie r Science Ltd. All rights reserved.