Abstract: Among various gases, ammonia is recognized as one of the most harmful and abundant toxic pollutants. Hence, precise monitoring of ammonia levels in the environment is consistently considered vital in safety discussions. In the era of the Internet of Things (IoT), the production of wearable gas sensors for rapid and selective detection of ammonia at room temperature has become increasingly necessary. Accordingly, this research aims to develop a conductive textile based on polyaniline (PANI) conducting polymer and reduced graphene oxide (rGO) nanosheets for use as a miniaturized ammonia gas sensor. In this study, cotton fabric samples were coated with graphene oxide (GO) using a dip-coating and drying method. For graphene oxide reduction, two different methods were employed: chemical reduction using sodium hydrosulfite after coating, and reduction of graphene oxide powder before coating using hydrazine. The polymer coating of PANI was carried out on the fabrics through in-situ chemical polymerization in two consecutive cycles. The results of FTIR and XRD analyses confirmed the successful reduction of GO to rGO. Additionally, FESEM images revealed the coating of cotton fabrics with PANI and rGO nanosheets. The results indicated that due to the elimination of oxygen-containing functional groups after GO reduction, the water contact angle increased. The surface resistance of fabric coated with graphene nanosheets increased with the number of coating cycles up to 20 cycles, resulting in a surface resistance of 835.3 ± 11.78 Ω/sq. Upon PANI coating on graphene-coated samples, the surface resistance significantly decreased. After 2 PANI coating cycles, the surface resistance reached 253.3 ± 3.51 Ω/sq. The sensor properties demonstrated that the response time of PANI/RGO/CF samples with 5 cycles of RGO coating was shorter than that of RGO/CF, PANI/CF, and PANI/RGO/CF samples with 10 cycles of RGO coating, and its recovery time was shorter than PANI/CF and PANI/RGO/CF samples. PANI/CF, PANI/RGO/CF with 5 cycles of RGO coating, and PANI/RGO/CF with 10 cycles of RGO coating maintained their response and recovery after exposure to ammonia gas and air for 10 cycles, confirming the good repeatability of the sensors. Furthermore, with an increase in ammonia gas concentration, the sensor response increased. Additionally, the stability of PANI/CF and PANI/RGO/CF sensors with 10 cycles of RGO coating was eva‎luated over 21 days, showing good stability after an initial decrease. In conclusion, the results of this study highlight the high potential of graphene-coated fabric and polyaniline-conductive polymer for the development of wearable ammonia gas sensors.

مصطفي يوسفي , وحيد عبادي

زهرا طالبي مزرعه شاهي , كميل نصوري