Enhanced room temperature ammonia gas sensing based on multichannel PSS-functionalized graphene /PANI network

Abstract

Disordered polymerization of polymers widens the polymerization degree distribution, which leads to uncontrollable thickness and significantly weakens their sensing performance. Herein, poly (sodium p-styrenesulfonate)-functionalized reduced graphene oxide (PSS-rGO) with multichannel chain structures coated with thin polyaniline layer (PSS-rGO/PANI) nanocomposites were synthesized via a facile interfacial polymerization route. The morphology and microstructure of the PSS-rGO/PANI nanocomposites were characterized using Fourier transform infrared spectra (FTIR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The flexible PSS-rGO/PANI-2 sensor exhibits excellent room temperature NH3 sensing performance, including a higher sensitivity of 362 % and a faster response/recovery time of 23/158 s towards 100 ppm NH3 than other PSS-rGO/PANI nanocomposites. In addition, the flexible PSS-rGO/PANI-2 sensor has a low detection limit of 10 ppb, superior selectivity, repeatability, and long-term stability over 75 days. Remarkably, the flexible PSS-rGO/PANI-2 sensor shows excellent humidity resistance (196±3%, 50 ppm) even at a high relative humidity of 80%. The gas sensing mechanism was systematically investigated through high protonation states and strong π–π conjugation of PSS-rGO/PANI. This work provides a convenient method to construct multichannel thin polyaniline layer-coated graphene nanocomposites and promotes their application in flexible wearable electronics.