Electrophoretic Deposition of Oxidized Multi-Walled Carbon Nanotubes on Stainless Steel for Ethanol Sensor

Abstract

This dissertation research describe the feasibility study and investigation of electrophoretic deposition of oxidized MWCNTs for the application in ethanol sensor. Ethanol sensors are attracting tremendous interest because of their wide spread application in industry, environmental monitoring, space exploration, biomedicine and pharmaceuticals. Ethanol sensors with high sensitivity and selectivity are required for leakage detection of explosive gases such as hydrogen and for real time detection of toxic and pathogenic gases in industries. There is also a storage demand for the ability to monitor and control our ordinary environment, especially with the increasing concern of the global warming. MWCNTs are used to obtain thin film by electrophoretic deposition. Before deposition, MWCNTs were purified and surface functionalized by concentrate nitric acid (HNO 3 ) under heating. The oxidized MWCNTs were characterized by FTIR. FTIR shows the presence of oxygenated functionalized groups as carboxylic acid and hydroxyl group on the surface of MWCNTs. The uniform electrophoretic deposition of MWCNTs are confirmed by SEM. Raman spectroscopy confirmed the deposited material was nothing other than MWCNTs. The EPD experiments were carried out by using oxidized MWCNTs on stainless steel plate at 10V at a constant time for 10 min and electrode were fixed at a distance of 1.5 cm. modification of carbon nanotubes with functional groups will greatly enhance the selectivity of the carbon nanotubes-based sensors. CNTs-based sensors have proved to work well at normal room temperature, which reduces power consumption of the device and enables the safer detection of flammable gases and alcohol. The resistance of electrophoretic deposition material was measured in closed glass chamber with digital multi-meter. Then sensitivity percentage was calculated. It was observed that the rate of % sensitivity increases with time and became saturated after certain time.