PTFE membrane electrodes with increased sensitivity for gas sensor applications
|PTFE membrane electrodes with increased sensitivity for gas sensor applications|
|Autor||Marion Wienecke, M.-C. Bunescu, K. Deistung, P. Fedtke, M. Pietrzak|
We report about different methods to increase the surface area of the membrane-electrode and the results of the surface morphology examination. After vacuum evaporation coating of the PTFE membranes with metals the surface morphology of the sintered PTFE membranes has been changed, due to the thermal stress relaxation during the cooling of the metallic film. The particular “hair morphology” of the surface has increased the three-phase boundary area, followed by an enhancement of the gas sensor sensitivity. A further improvement of the utilisation efficiency of the metal catalyst and of the sensitivity (from the “ppm” to “ppb” gas concentration level) was obtained using the new membrane-electrode assembly composed of PTFE membrane and a nanocomposite material of carbon nanotubes (CNT) and PTFE.