Humidity Sensing Properties of Multiwalled Carbon NanotubePolyvinyl Alcohol Nanocomposite Films

Effect of humidity on the sensing properties of flexible nanocomposite thin films, such as variation of resistance with RH, hysteresis, response time and recovery time, fabricated using functionalized multiwalled carbon nanotubes (f-MWCNT) and polyvinyl alcohol (PVA) have been investigated. Scanning electron microscopy (SEM), UV-Vis spectroscopy, and X-ray diffraction (XRD) were used to characterize f-MWCNT-PVA nanocomposite thin films. The nanocomposite film with 5 wt% MWNTs loading shows promising results for humidity detection in relative humidity (RH) range of 11-94% RH. The resistance measured at 25 °C varied by more than four orders of magnitude in this RH range. This kind of nanocomposite film has many advantages since it is flexible and has good mechanical properties. Also a possible humidity-sensing mechanism of the MWCNTs/PVA composite thin film is discussed.