Effect of acid treatment on the physico-chemical properties of Nafion 117 membrane

In this work, the effect on the physico-chemical properties of Nafion 117 membrane due to the treatment with HCl, H2SO4 and HNO3 was studied. Water uptake, crystallinity, proton conductivity and water dynamics were evaluated on treated and non-treated membranes. An increase in the water uptake and conductivity and a decrease in the crystallinity were observed in treated membranes in comparison with the untreated one. The water dynamics, studied by spin-spin NMR relaxometry, suggests that treated membranes have a more uniform channel size distribution. The treatment with HCl and HNO3 showed higher conductivity and water uptake than H2SO4.