Humidity sensing of an epoxy/MWCNT composite by electrical conductivity measurements

An epoxy/CNT composite material with a low concentration of multiwall carbon nanotubes (0.5wt%) in a diglycidil-ether bisphenol-A based epoxy matrix has been shown to be applicable, when maintained at a constant temperature, as humidity sensing element. An almost linear decrease of the electrical conductivity with increase of the sample humidity has been measured. The investigated samples with vaporated gold contacts exhibited a perfect ohmic behavior and an excellent long-term stability, even after prolonged immersion of the sample into distilled water. © 2013 SPIE.