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

Abstract

This dissertation research describes the feasibility study and investigation of Electrophoretic Deposition of oxidized MWCNTs on stainless steel for LPG sensor. Gas sensors are attracting tremendous interest because of their wide spread application in industry, environmental monitoring, space exploration, biomedicine and pharmaceuticals. Gas 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 strong demand for the ability to monitor and control our ambient environment, especially with the increasing concern of global warming. MWCNTs are used to obtain thin film by Electrophoretic Deposition. Before deposition MWCNTs were purified and surface functionalized by conc. HNO 3 . 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 MWCNTs. The EPD experiments were carried out by using oxidized MWCNTs on stainless steel plate at 10V at a constant time of 10 min. and fix electrode distance of 1.5 cm. Modification of carbon nanotubes with functional groups will greatly enhance the selectivity of the carbon nanotubes-based gas sensors have proved to work well at room temperature, which reduces power consumption of the device and enables the safer detection of flammable gases. The resistance of Electrophoretic deposited material was measured in closed glass chamber with digital multimeter. Then % sensitivity was calculated. It was observed that the rate of sensitivity increases with time and become constant after certain time.