ABSTRACT
Abstract Fabrication of novel composite proton exchange membranes (PEMs) comprising a fully sulfonated polyarylenethioethersulfone (SPTES) and sulfonated poly(p-phenylene benzobisimidazole) (SPBI) and the evaluation of the membrane properties are described. The composite membrane was obtained via a solventcast process in a mixture of DMAc and methanol as solvents. The composite membrane proton conductivity, as measured by four-probe impedance spectroscopy, was found to increase with increase in the SPTES content in the composite. The highest proton conductivity obtained was ∼80 mS/cm at 65◦C and 85% relative humidity for the SPTES/SPBI 70/30 composite membrane which was considerably less than the proton conductivity of 300 mS/cm for the pure SPTES membrane under the same conditions, but it was found that the swelling of the composite membranes was dramatically reduced due to the decreased water uptake of the composite membranes relative to that of SPTES. The morphology of the SPTES/SPBI composite membranes was also examined by a combination of techniques such as Wide Angle X-ray Diffraction (WAXD), Scanning Electron Microscopy (SEM) and tapping mode Atomic Force Microscopy (AFM) to confirm the dispersion of SPBI and study the composite micro-structure. These studies also involved the preliminary evaluation of the MEA (Membrane Electrode Assembly) performance of the composite membranes for H2/O2 fuel cells applications.
