Processable polyaniline modified biodegradable substrates as the electrode material for gas sensor application

Gas sensors are extremely important because of their broad application in industrial production and everyday life. However, many conventional gas sensors require high operating temperatures and are fabricated from non-biodegradable materials, leading to increased energy consumption and disposal concerns. To address these limitations, processable conducting materials with sensing properties coated on natural and biodegradable substrates are highly desirable. In this study, organically processable polyaniline was synthesized, coated on natural substrates such as banana bracts (BB), fish scales (FS), and paper and was used as the electrode for sensing toxic gases such as ammonia (NH 3 ), carbon monoxide (CO), and sulfur dioxide (SO 2 ). Organically processable polyaniline (PANI)-maleic acid (MA)-dioctyl sodium sulfosuccinate (PAMD) was synthesized by the chemical oxidative polymerization of aniline in the presence of MA dopant, dioctyl sodium sulfosuccinate (DSS) surfactant, and ammonium peroxydisulfate initiator. The integration of DSS along with the PANI chains was confirmed by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) studies, and UV–visible (UV–VIS) spectroscopy. The PAMD dispersion coated on BB, FS, and paper substrates was exposed to different toxic gases, and the corresponding resistivity changes were monitored. Among the tested substrates, PAMD coated on FS substrate exhibited the highest gas-sensing response, showing good linearity toward NH 3 , CO, and SO 2 detection. The sensor also demonstrated low detection limits, excellent repeatability, and retained a high percentage of its initial response after multiple sensing cycles, confirming its good reusability and long-term stability.