Humidity sensitivity of thin films based dispersed multi-walled carbon nanotubes

The electrical transport properties of the thin films based dispersed carbon nanotubes (MWNT) when exposed to humid environment in various temperatures was investigated. The MWNTs dispersed in three different kinds of surfactants (sodium dodecylbenzene sulfonate (SDBS), sodium dodecylsulfate (SDS), and Triton X-100) were deposited on flexible polymer substrates (Polyethylene terephthalate - PET) through drop casting method, these samples were later exposed to humidity change at various temperature. The resistance increases exponentially with relative humidity (RH) from 10% to 90%. Moreover, it shows that MWNT dispersed in an ionic surfactant having a benzene ring in our case SDBS demonstrate higher humidity sensitive properties, this surfactant shows also good dispensability as well as good electrical properties at room temperature, the only drawback was the less stability at high temperatures compared to the other used surfactant, because of the forming of the virtual short circuit effect. Generally, the humidity sensitivity of thin films based MWNT emphasize it potential as a humidity sensitive material.