I know that the IEC is directly related to the proton conductivity but is it only hence the hydrophilic/hydrophobic (polymere backbone) phase separation so the membrane can form channels during hydration? Or do the acidic groups somehow contribute to the proton conductivity by dissociating in water and increasing the amount of excess protons thus increasing the amount of structural diffusion (Grotthuss like) in the overall proton transfer process?
Thank you for any ideas! I think i read all the relevant publications (mostly Kreuer et al.) but this question remains unsolved...