Mechanical properties and ionic conductivity of electrospun quaternary ammonium ionomers

Solution processable cationic ionomers are receiving widespread attention for their promising roles as anionic exchange membranes, antimicrobial coatings, and dialysis membranes. The ion conductivity can be improved by increasing the materialʹs ion-exchange capacity; however this often results in poor mechanical properties. Here we report the synthesis of solution processable polysulfone ionomers with a tunable density of quaternary ammonium functional groups. Electrospinning is explored to create fibrous mats that can be solvent welded and filled with a second material to modulate membrane properties. The tradeoff between hydroxide anion conductivity and mechanical properties in solution cast and electrospun mats is assessed, and electrospinning is shown to improve mechanical properties of the fiber phase with relatively small losses in ion conductivity.