Fabrication of Conducting Polyaniline–Betel Nut Fiber Filaments with Potential Ammonia Gas Sensing Behavior

Abstract

Polyaniline–betel nut fiber (PANI/BNF) filaments have been prepared for the first time by in situ polymerization with potential application as ammonia gas sensor at room temperature. A sheath of polyaniline is formed surrounding the BNF filament, which is evident from scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analyses. This morphological structure makes it easy enough to fit the filaments directly between electrodes for resistive ammonia gas sensor studies without the need of any other polymeric matrix, indicating novelty of the work. A red shift with increase in the amount of BNF is observed in the UV–Vis spectra. The composite exhibits increased electrical conductivity as revealed by electrochemical impedance spectroscopy (EIS), which is a requisite for resistive gas sensors. The novel PANI/BNF sensor has average ammonia-sensing response of 28.2% toward 100 ppm of ammonia with 10 ppm detection limit. The sensor fits in a linear plot of response vs. NH3 concentration from 10 to 200 ppm with good response and recovery capabilities. PANI/BNF filaments with increased conductivity, thermal stability, and ammonia-sensing properties open new scope for their application in gadgets like electrodes for supercapacitors, other gas sensors, and electromagnetic shields.

Keywords

• polyaniline
• betel nut fiber (bnf)
• electrical conductivity
• electrochemical impedance spectroscopy (eis)
• ammonia
• sensitivity