Electrospun and cross-linked nanofiber composite poly(aryl ether sulfone) for anion exchange membranes

Poly(aryl ether sulfone) nanofiber with quaternary ammonium side chains (QPAES-90/10) was electrospun into bead-free nanofibers. The electrospun fibers were cross-linked to embed in an ionomer matrix while maintaining the intact fiber morphology. A series of characterization studies showed that cross-linked nanofibers profoundly affect the performance of membranes. As the result, the fiber membranes possess both enhanced mechanical properties and increased ion exchange capacity. The composite membrane exhibits lower swelling and better ion conductivity than membranes without nanofibers, suggesting that the nanofiber network containing quaternary amine groups promotes the formation of anion transport pathways. These films show lower methanol permeability and higher selectivity than the neat matrix. Therefore, this strategy of incorporating cross-linked and electrospun nanofibers into membranes is an effective method for developing anion exchange membrane material as a competitive candidate material for fuel cells.