Pure Appl. Chem., 2006, Vol. 78, No. 9, pp. 1781-1791
doi:10.1351/pac200678091781
Sulfonated polyether ether ketone (PEEK-WC)/phosphotungstic acid composite: Preparation and characterization of the fuel cell membranes*
Ji Shan, Guntars Vaivars, Hongze Luo, Rushanah Mohamed, and Vladimir Linkov
Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville, 7535, Cape Town, Western Cape, South Africa
Abstract:
Sulfonated poly(oxa-p-phenylene-3,3-phthalido-p-phenylene-oxa-p-phenylene-oxy-phenylene) (PEEK-WC) membranes with various degrees of sulfonation (DS) were prepared, and their electrochemical and thermal properties were studied. Composites were formed by adding the hydrated phosphotungstic acid (PWA). The membrane (DS = 0.96, PWA = 50 %) conductivity was increased to 3.5 x 10-2 S cm-1 at room temperature and 6.0 x 10-2 S cm-1 at 80 °C. The composite membrane with a low amount of PWA embedded, showed lower methanol crossover in comparison to Nafion®. The addition of PWA increased the water retention of the composite membrane.
Keywords: direct methanol fuel cells; hydrated phosphotungstic acid; membranes; nanocomposites; proton conductivity; sulfonated PEEK-WC.
*Paper based on a presentation at the 3rd IUPAC Workshop on New Directions in Chemistry - Workshop on Nanostructured Advanced Materials (WAM III), Stellenbosch, South Africa, 5-9 September 2005. Other presentations are published in this issue, pp. 1619-1801.