Electrical properties of polypyrrole gas sensors fabricated under various pretreatment conditions

The polypyrrole (Ppy) incorporated with DBSA and APS was synthesized by chemical polymerization at 0 °C under atmospheric conditions. Ppy films were prepared by the dip coating method on the alumina substrate with interdigitated electrodes in order to employ the gas sensor. The electrical properties of the sensors, such as sensitivity, response and recovery time, reproducibility and long-term stability were investigated in the flow systems after various pretreatments. The electrical properties of the sensors depended on the pretreatment conditions. Soaking pretreatment resulted in a quick response and recovery time of the sensor and maintained electrical properties of the sensor for 3 months. Initial resistance of the sensor decreased with thermal treatment and this improved the stability of the sensor.