Highly sensitive and selective polyaniline thin-film sensors for detecting SF6 decomposition products at room temperature

• PANI was first explored to detect SF6 decomposition products.
• PANI thin film sensors show superior gas sensing characteristics.
• Increasing concentration the sensor response will saturate.
• The gas sensing mechanism relies on the species of gas.

Gas sensors for detecting SF6 decomposition products under partial discharge have been considered as an effective and low-cost apparatus for electrical insulation diagnosis of gas-insulated switchgear. A new gas sensor was developed using polyaniline (PANI) conducting polymers. HCl-doped PANI was successfully synthesized via in situ chemical oxidation polymerization. The formation, structure, and morphology of PANI were analyzed with Fourier-transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscopy, respectively. PANI thin films were deposited onto the substrates by drop coating. Their gas-sensing properties to H2S, SO2, SOF2, and SO2F2 were measured. The PANI sensors showed excellent sensitivity of −58% to a low concentration (10 ppm) of H2S. The plausible response and recovery mechanism of PANI thin-film sensors were also discussed.