Proton Conducting Polyoxometalate/Polypyrrole Films and Their Humidity Sensing Performance

Proton conducting polyoxometalate has received considerable attention because of its unique structural properties. This article reports the fabrication of hybrid polymer films of polypyrrole/polyoxometalate and their resistive-type humidity sensing performance. Hybrid polymer films with different thicknesses were prepared via the coelectrodeposition of free pyrrole monomers with metal oxide clusters. A sensing response of 1.9 s and a recovery time of 1.1 s were exhibited in a 59 nm thick sample at 98% relative humidity and in a sensing range of 11–98% relative humidity. The outstanding sensing in the polypyrrole chain could be ascribed to the synergistic effect of the proton acid doping structure and the oxidation doping structure. The humidity sensor based on the nanocomposite was repeatable even after two months with good response and recovery times.