Liquefied petroleum gas sensing activity of betel nut fiber‐polyaniline conducting composites synthesized by time‐controlled in situ polymerization

Abstract

AbstractIn this paper, we report the liquefied petroleum gas (LPG) sensing behavior of polyaniline‐betel nut fiber (PANI/BNF) composite synthesized through a one‐step in situ oxidative polymerization method using HCl, H2SO4 and H3PO4 as doping acids. The deposition of emeraldine salt (ES) form of PANI on betel nut filament surface is explained by Fourier‐transform infrared spectroscopy (FT‐IR) and Ultraviolet–Visible (UV–vis) spectroscopy. Scanning electron microscopy (SEM) revealed that PANI particle size decreased and the thickness of the coated PANI layer increased with reaction time. Optical band gap of Polyaniline‐Betel nut fiber composites (PB) PB‐2, PB‐4 and PB‐6 were found be 3.68, 3.37, and 2.75 eV using the Tauc plot. X‐ray diffraction (XRD) analysis and thermogravimetric (TG) analysis showed that HCl‐doped PANI/BNF composites have high crystallinity and thermal stability as compared to the composites formed using H2SO4 and H3PO4. The electrical conductivity of the composites was determined by using a multimeter (Keithley Model 2000). The conducting filaments showed good resistive sensing activity toward LPG with minimum (100 ppm) 26% and maximum (1300 ppm) 44% of response sensitivity with decreasing response time and increasing recovery time. The plausible response mechanism of PANI/cellulose sensor toward LPG operating at room temperature is also discussed.