Sulfonated poly(ether sulfone ether ketone ketone)/sulfonated poly(ether sulfone) blend membranes with reduced methanol permeability

Proton exchange membranes were prepared by blending sulfonated poly(ether sulfone ether ketone ketone) (SPESEKK) with sulfonated poly(ether sulfone) (SPES). The morphology, tensile strength, proton conductivity and methanol permeability of the blend membranes were investigated. The scanning electron microscope and transmission electron microscope observation indicates the good dispersion of the SPES in SPESEKK polymer matrix. The addition of SPES also enhances the tensile strength of the SPESEKK membrane. The blend membrane shows lower methanol diffusivity and higher proton conductivity with comparison to the pure SPESEKK membrane, ascribing to the inhabitation of the player SPES to methanol permeation and facilitation of the increment of sulfonic acid groups to the proton transport. The SPESEKK/SPES 5 : 5 membrane exhibits an appreciable tensile strength of 52.3 MPa and a reduced methanol permeability of 6.6 × 10⁻⁷ cm² s⁻¹. This SPESEKK/SPES composite membrane shows a potential feasibility as a promising electrolyte for direct methanol fuel cells.