FLEXIBLE AMMONIA GAS SENSOR BASED ON POLYANILINE

In this paper we prepared flexible ammonia (NH3) gas sensor based on polyaniline (PAni) as an active sensing thin film layer. The sensors function was based on chemiresistive principle with thin film deposited on top of interdigitated electrodes. We measured the change in resistance of the thin film under gas exposure. The PET based foil has been used as the sensors substrate. The Interdigitated electrodes (IDE) has been printed with Fujifilm Dimatix DMP 2831 inkjet printer by nanocoloid silver ink. The active thin film has been prepared by drop casting method from polyaniline nanoparticle dispersion. The morphology of thin films surface was characterized by atomic force microscopy (AFM). The sensors response was investigated in a gas chamber, and the gas flow was controlled by mass flow meters. The sensitivity towards various gases under different concentration in synthetic air has been tested. The tested gases were NH3, NO2, CO2 and CO. The measurement of the sensors response to the different levels of humidity was also conducted. All the measurements were performed at room temperature, which is important feature for the sensor to be able to operate in hazardous environment and it facilitates low-power operation of the sensor as well. We also observed the long-term stability of the sensors response, as well as the effect of bending of the sensing platform on the sensors response and stability.