The effect of residual solvent on the morphology and properties of semi-interpenetrating polymer network membranes based on sulfonated poly(ether ether ketone) and crosslinked poly(2-acrylamido-2-methyl-1-propanesulphonic acid)

To further improve proton conductivity of semi-interpenetrating polymer network membranes based on sulfonated poly(ether ether ketone) (SPEEK) and crosslinked poly(2-acrylamido-2-methyl-1-propanesulphonic acid) (CrPAMPS), the attempt was made to photo-initiate the polymerization and crosslinking of AMPS in a swollen state of SPEEK membranes, where the residual solvent (RS) content was carefully controlled during the synthesis. The effect of RS on membrane structure and properties were investigated. The proton conductivity of the membrane with 33 wt% RS was found to increase more than 60% than that of the "dry" membrane which actually contained 13 wt% RS. It was suggested the existence of RS content might help the formation of large and well-connected hydrophilic domains that facilitate proton transport.