Spray deposited carbon nanotubes for organic vapour sensors

In this paper a study of chemiresistor sensors based on Single Wall Carbon Nanotube films deposited at low temperature by means of a spray technique is presented. A nanodispersion of nanotube powder in a non-polar 1,2-Dichloroethane solvent was used as starting solution. Electron Microscopy in Scanning and Transmission mode were used in order to verify the morphological properties of the deposited films. Conductivity of single walled carbon nanotubes (SWNTs) were measured in various organic solvent vapours environments. The solvents used are characterized by different polarities and volume fractions of saturated vapours defined by the vapour pressure. The results show that the electrical resistance of the sensors increases when exposed to solvent vapours. Finally the effect of Teflon-like coating on the sensitivity yield is presented and discussed.