Fabrication of Ammonia Gas Sensor Using In Situ Synthesis of Polypyrrole-Zinc Oxide Nanorod Nanocomposites on Textiles

Abstract

Abstract A flexible textile modified with Polypyrrole and ZnO was fabricated through a polymerization process, effectively converting an insulating textile into a conductive one. The resulting modified textile was thoroughly characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and contact angle measurement. The performance of the sensor was evaluated for its ability to detect ammonia vapors at room temperature by measuring changes in resistance. The presence of ZnO significantly enhanced the sensor's performance, resulting in a 21.8% increase in sensitivity towards 20 ppm of ammonia. Notably, the sensor exhibited selectivity towards ammonia with a rapid response time of 24 seconds and a recovery time of 118 seconds for continuous measurements over 20 cycles. It also displayed excellent linearity across different concentrations of ammonia, ranging from 20 to 100 ppm. The ammonia sensing mechanism was elucidated based on the formation of a p-n junction between polypyrrole and ZnO, along with the potentization of polypyrrole. This understanding of the sensing mechanism is crucial for optimizing the sensor's performance and sensitivity. Furthermore, the sensor demonstrated minimal impact from humidity levels within the range of 23% to 86%, indicating its robust stability over a prolonged period of seven weeks. This characteristic ensures reliable and consistent sensing capabilities in various environmental conditions.