Chemiresistive humidity sensor based on chitosan/zinc oxide/single-walled carbon nanotube composite film

•Chemiresistive humidity sensor based on chitosan/ZnO/SWCNT composite is prepared.•Chitosan can obviously improve the response of ZnO/SWCNT hybrid.•Chitosan/ZnO/SWCNT composite exhibits a high sensitivity and a good reproducibility.•Relative humidity-dependent relation corresponds to the water sorption nature of chitosan. A chemiresistive humidity sensor based on chitosan (CS)/zinc oxide/single-walled carbon nanotube (SWCNT) composite was developed. The sensor film was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The humidity sensing properties were investigated in a wide range of relative humidity (RH) (11%–97%) at room temperature. The SWCNT response to humidity was significantly improved with the aid of conjugate material in the composite, especially the CS. The composite also exhibited good reproducibility. The RH-dependent relationship revealed that the sensing response corresponded to the water sorption characteristic of CS. The sensing mechanism was attributed to the swelling effect of CS surrounding the nanotubes through which the hopping conduction path between nanotubes changed.