The enhanced alcohol sensing response of multiwalled carbon nanotube networks induced by alkyl diamine treatment

The vapor sensing properties of multiwalled carbon nanotube networks (MWCNT-Ns) of randomly entangled pristine nanotubes and the nanotubes treated by KMnO4-H2SO4, ethylenediamine and hexamethylenediamine deposited on polyurethane supporting non-woven membrane to vapors of linear alcohols (methanol, ethanol, 1-propanol, 1-butanol and 1-pentanol) are measured by monitoring of electrical resistance of the networks. The substantial increase is observed in the sensor response of the networks to vapors of the alcohols induced by the alkyl diamine treatments of nanotubes in comparison with those of pristine and the KMnO4 treated MWCNT-Ns. Analysis of the enhanced linear alcohol sensing properties of the MWCNT-Ns is concentrated on the interactions between the network and the alcohols and the amount of adsorbed alcohols on the networks by using the Fourier transform infrared (FTIR) spectroscopy analysis and the gravimetric measurements. The scanning electron microscopy, Brunauer-Emmett-Teller surface area and thermal gravimetric analyses are used for the characterization of the networks as well as FTIR. The result shows that the enhanced vapor sensor response can be attributed to the extent of the interaction area between the carbon nanotubes and the alcohols.