Gas sensors based on multiple-walled carbon nanotubes-polyethylene oxide films for toluene vapor detection

Two kinds of toluene vapor sensors with different sensitive film structures, i.e., multi-walled carbon nanotubes (MWCNTs)-polyethylene oxide (PEO) composite film and MWCNTs-PEO bilayer film were fabricated. Both sensors were obtained by airbrushing the sensitive films on interdigitated electrodes (IDE). Response performances of both sensors to toluene vapor at room temperature were investigated. Scanning electron microscope (SEM) was used for morphology analysis of the sensitive films. The experimental results showed that sensors with bilayer films revealed a larger sensitivity than that with the composite films. The response and recovery times of both sensors were within 8 s. Moreover, sensors with bilayer films exhibited a modest selectivity to toluene vapor. The sensing mechanisms of both sensors were studied as well.