Polyaniline Sensors for Early Detection of Insect Infestation

The ability of a chemiresistor sensor with a polyaniline active layer to detect insect infestation was investigated. The sensor detected various volatile organic compounds produced by plants, emitted as a defense mechanism when attacked by herbivores. This sensor was easy to fabricate and cost only 2 cents per each sensor fabricated. The platform of the wafer was silicon based, containing interdigitated electrodes. The sensors were stable under various humidity conditions, but showed unusual behavior when studied under various temperatures. In the temperature range −48–7°C, the resistance increased with increasing temperature, while the resistance decreased from 7–59°C, and increased with increasing temperature till 80°C. The sensors also displayed a hysteresis loop during cooling and heating cycles.