Morphological Control of Electrospun Nafion Nanofiber Mats

There are a number of applications where Nafion must be electrospun into a nanofiber mat, including composite fuel cell membranes. Unfortunately, Nafion perfluorosulfonic acid polymer is notoriously difficult to electrospin and requires the presence of a high molecular weight carrier polymer in the electrospinning solution. In this paper, we report on the morphology of electrospun Nafion mats that were created using a low concentration (1-2 wt%) of poly(ethylene oxide) (PEO) as a carrier polymer. The average diameter of well-formed Nafion/PEO nanofiber mats ranged from 300 nm to 900 nm. The effects of electrospinning conditions, i.e., air humidity, polymer solution solvent, carrier polymer molecular weight, electrospinning voltage, and electrospinning flow rate, on the quality of the electrospun mat (the presence/absence of unwanted bead-on-fiber morphologies) and the mat-averaged nanofiber diameter are presented and discussed.