Ammonia sensors based on sensitive polyaniline films

We propose a new type of ammonia sensor with polyaniline (electroconducting polymer) as the sensitive element. Such sensors are characterized by high sensitivity, wide range of measured concentrations (1-2000 ppm) and high stability of electrical parameters. The use of polyaniline ensures high chemical stability of the sensors in oxidizing ambients. A sensor design based on a silicon chip custom-packed into a linear plastic case is presented. The chip is provided with a system of heaters and thermometers to check the temperature regime of sensor operation. We have studied I-V curves, temperature, concentration and kinetic characteristics of the sensors, as well as their ageing. The possibility for thermoregeneration of the sensor parameters after long-term functioning in an ammonia ambient is emphasized.