Synthesis of (Si-PWA)-PVA/PTFE high-temperature proton-conducting composite membrane for DMFC. (30th September 2020) - Pagidi, Aruna
Abstract: The inorganic silica immobilized PWA based (Si-PWA)-PVA/PTFE composite membrane was developed by an amalgamation of pore filling and layer by layer (LBL) casting. The composition of the top layer was optimized to be 0.3 M PWA: 0.2 M TEOS: 0.15PVA concerning to proton-conductivity and methanol permeability of the membrane. Surface morphological studies and elemental analysis were carried out by using SEM-EDX. The FT-IR and XRD analysis had confirmed the intercalation of sol with PTFE. Thermal deformation of the membrane was studied by TGA and it is stable up to 180 °C. Ion exchange capacity and water uptake were determined to be 2.38 meq per gram and 21.7%. The membrane has exhibited maximum proton conductivity of 41.2 mS cm −1 at 100 °C. The membrane has significantly lower methanol permeability of 3.2 × 10 −7 cm 2 S −1 compared to that of Nafion117 (7.9 × 10 −7 cm 2 S −1 ) at 28 °C and the same trend was observed at 40, 60, and 80 °C. The (Si-PWA)-PVA/PTFE composite membrane is showed enhanced proton conductivity and lower methanol permeability at elevated temperatures. Graphical abstract: Image 1 Highlights: The (Si-PWA)-PVA/PTFE composite membrane was successfully synthesized. The membrane exhibited increased proton conductivity of 41.2 mS cm -1 at 100 °C. The membrane has significantly lower methanol permeability compared to Nafion117. The membrane was thermally stable up to 180 °C with aggregate weight loss of 4.1%. The composite membrane is promising for application in high-temperature DMFC.