Evaluation of electrospun nanofiber formation of perfluorosulfonic acid and poly ( N -vinylpyrrolidone) through solution rheology

Electrospinning performance of 5–52 wt% perfluorosulfonic acid (PFSA), poly ( N -vinylpyrrolidone) (PVP), and PFSA/PVP blends in N , N -dimethylformamide (DMF) with various PFSA/PVP ratios were systematically investigated in respective of solutions properties, mainly surface tension and rheological properties. Mechanical relaxation time τ M calculated from rheological results happens to be closely correlated with nanofiber morphology, and is used to evaluate the electrospinnability. Polymer solutions with higher τ M show better electrospinnability. Morphologies of the electrospun samples were observed by Scanning electronic microscopy. The results show that the pure PFSA solutions, even with a quite high concentration up to 52 wt%, fail to be electrospun and possess a very low τ M . Addition of PVP improves electrospinnability of PFSA and increases τ M . The electrospinnability of PFSA/PVP/DMF solutions can be manipulated by changing the ratio of PFSA to PVP and the total polymer concentration of the mixed solutions. The PFSA nanofiber mats with a small fraction of PVP (<8 wt%) with the average diameter of 370 nm were successfully obtained.