Summary: Based on Flory–Huggins parameters (χ), the miscibility and the effect of morphological change on proton conductivity and methanol permeability of partially sulfonated polystyrene (SPS) and partially sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO), having an identical ion exchange capacity, were investigated. When 50 wt.‐% of SPPO was blended, both the proton conductivity and methanol permeability had the highest values, which resulted from the change of amorphous domains and the hydrogen bonding between the two ionomers.
The proton conductivities, water uptake and methanol permeability for the SPPO/SPS blend membranes studied here. The membranes with 50 wt.‐% SPPO clearly showed the greatest increase in these properties.