Determination of the effect of temperature and humidity on the O 2 sorption in sulfonated poly(arylene ether sulfone) membranes

Abstract

Gas transport properties of O 2 in poly(perfluoro sulfonic acid) (Nafion 112) and disulfonated poly(arylene ether sulfone) were compared. While O 2 permeabilities were lower in poly(arylene ether sulfone) when compared to poly(perfluoro sulfonic acid), the O 2 gas sorption in the former was higher than in Nafion 112. Sorption measurements have been carried out both under non-humidified and humidified conditions. Under non-humidified conditions, the enthalpies of sorption (Δ H s) were calculated as a function of pressure for both Nafion 112 and disulfonated poly(arylene ether sulfone). The |Δ H s| ranged from 6.58 to 7.30 kJ/mol for the disulfonated poly(arylene ether sulfone) and 4.94 to 5.36 kJ/mol for Nafion 112 sample. O 2 sorption was also measured as a function of relative humidity and temperature at a normal proton exchange membrane (PEM) fuel cell operating pressure of 1 atm. The disulfonated poly(arylene ether sulfone) was found to have a higher percent O 2 mass uptake than Nafion 112. While under dry conditions, O 2 sorption followed Henry's law, in the presence of humidity, O 2 sorption followed Type IV behavior.