Functionalised multi-walled carbon nanotubes for chemical vapour detection

Oxygen plasma functionalised Multi–Walled Carbon Nanotubes (MWCNT) were used to prepare gas sensors that can operate at room temperature. Alumina substrates with interdigitated gold electrodes were employed as transducers and the air–brushing method was used to coat them with carbon nanotube film. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) images of deposited MWCNT were obtained. The sensing properties in the presence of acetone and ethanol vapours were measured by impedance spectroscopy. The resistance variation of the prepared MWCNT films increases with the concentration of the vapours. Limits of detection of 1.76 ppm and 4.03 ppm for ethanol and acetone were obtained, respectively, with good reproducibility.