Preparation of bilayer/three-layer PEO-carbon nanotube composite thin films and their toluene-sensing application

Abstract

The bilayer poly (ethylene oxide)/multiple-walled carbon nanotubes (PEO/MWCNTs) and three-layer PEO/MWCNTs/PEO composite thin films were fabricated with the spraying process on the interdigitated transducers (IDTs) as gas sensors for toluene-sensing application. Compared with the bilayer thin film sensor, the sensor with three-layer thin films exhibited higher response values and better recovery property. The microstructures of sensing films were characterized by scanning electron microscopy (SEM) to indicate that the better sensing response of three-layer thin films might be ascribed to the sufficient adsorption of toluene molecules on the surfaces of upper and bottom PEO films. The selectivity of the three-layer film sensor was further investigated by comparing responses upon exposure to different interference vapors with the response to toluene exposure, and much higher response was observed in the case of toluene. Good repeatability of the three-layer film sensor was also observed.