Polyaniline-based room temperature ammonia gas sensor employing hybrid organic-inorganic substrate

Abstract

Air pollution poses a serious threat to public health, and gas sensors for detection of the pollution has gained great attention over the past decades. In this work, a novel idea based on the substrate material integrated by structure and function was built to prepare NH3 sensor with an improving sensing properties. Hybrid organic–inorganic sol gel with methacryloxy and epoxy groups was first synthesized. A hybrid organic–inorganic substrate was then prepared based on continuous condensation, radical polymerization and anionic polymerization. The thermal stability and microstructural of the hybrid substrate were studied and the results indicated that the hybrid has excellent thermal and structural stability. Then, polyaniline (PANI) was directly loaded on the hybrid substrate due to hydrogen bonding though a facile in-situ polymerization method to fabricate a PANI/hybrid nanocomposite for NH3 sensing. The hydroxyl groups generated from the epoxide ring-open reaction and silane hydrolysis condensation contribute to improve the sensing properties. This sensor showed superior selectivity and reproducibility to 50 ppm NH3 at room temperature. The low detection limit towards NH3 at room temperature can reach 1 ppm. This strategy may provide a promising and straightforward method in gas sensing electronics at room temperature.