One step synthesis of PANI/Fe₂O₃ nanocomposites and flexible film for enhanced NH₃ sensing performance at room temperature

Novel sea cucumber-shaped polyaniline/ferric oxide (PANI/Fe₂O₃) nanocomposites were synthesized using a simple and efficient one step hydrothermal process, and the nanocomposites were further assembled onto a polyethylene terephthalate (PET) flexible substrate. Through the monitoring of the resistance of the PANI/Fe₂O₃ nanocomposites thick films and PANI/Fe₂O₃-PET flexible sensors, the responses of the sensors to various 100 ppm gases including methanol, triethylamine, aniline and another five gases were obtained. It was found that two kinds of sensors exhibit a high selectivity towards NH₃. The PANI/Fe₂O₃ nanocomposites-based sensor has a good response and a low detection limit (0.3 ppm) at room temperature (20 ± 5 °C). It also shows a good linearity relationship in a certain concentration of NH₃. After assembling into the PANI/Fe₂O₃-PET flexible film sensor, the response of the sensor is significantly increased to 6.12 for 100 ppm NH₃, the detection limit is as low as 0.5 ppm, and the sensor shows good stability and linearity, which is more conducive to the application of such a material in wearable gas sensors. (paper)