Electrospun fibres from polyvinyl alcohol, poly(styrene sulphonic acid-co-maleic acid), and imidazole for proton exchange membranes

Abstract

Electrospun fibres from polyvinyl alcohol (PVA), poly(styrene sulphonic acid-co-maleic acid) (PSSA-MA), and imidazole for potential use as proton conducting membranes at elevated temperatures were prepared and characterized. The effect of PSSA-MA content (9, 17, 25, 33, 42, and 50% by weight of PVA) on solution properties was investigated. Fibre mats were obtained from solutions with 9-33% PSSA-MA. Solution viscosity increased with increasing PSSA-MA until reaching a maximum at 33% PSSA-MA. The effect of PSSA-MA content on fibre size and morphology was studied using scanning electron microscopy. Fibre diameter was found to increase with increasing solution viscosity. A solution with 25% PSSA-MA provided uniform and bead-free fibres with an average diameter of 485 nm. Thermal crosslinking of electrospun fibres was confirmed by attenuated total reflection Fourier transform infrared spectroscopy and thermogravimetric analysis. Electrospun fibres were thermally stable up to 250 °C. Fibres containing 25% PSSA-MA had a proton conductivity in nonhumidified conditions comparable to that of a solvent-cast membrane with the same composition. The proton conductivity of a solvent-cast membrane was slightly higher than that of fibres over the temperature range studied.