Synthesis of methanol blocking PVA-TiO2 cation exchange membrane for direct methanol alkaline fuel cell

Polyvinyl alcohol (PVA) based cation exchange membrane has been synthesized for direct methanol alkaline fuel (DMAFC) cells by phase inversion technique coupled with chemical reaction. Nanocomposite membranes have been prepared by adding different amounts of titanium dioxide (TiO2) nanoparticles into the sulfonated PVA solution. PVA was sulfonated by sulfosuccinic acid solution. Sodium ion conducting membranes are formed by a typical chemical reaction induced phase inversion process, using a nonsolvent bath of sodium hydroxide (NaOH) and sodium sulfate (Na2SO4). The phase inversion technique coupled with chemical reaction significantly modified the chemical structure; improved thermal, mechanical, and surface properties of the sulfonated PVA based nanocomposite membrane. The mechanical and thermal properties of the membrane were investigated by UTM and TGA respectively. The chemical structure of membranes was analyzed by FTIR spectrometer. The presence of the TiO2 nanoparticles and sodium ions in the composite membrane was analyzed with the EDX technique. The surface morphology of membranes was studied by SEM micrographs. Moreover, water uptake, sodium ion conductivity, and methanol permeability of the membrane were altered with varying amounts of TiO2. Surface modified TiO2 nanoparticles enhanced the ionic conductivity of the composite membrane to the range of 10-(-2) S/cm. Furthermore, the value of the methanol permeability was obtained in the order of 10(-7) Cm-2/S.