Hydrogen sulfide sensors based on PANI/f-SWCNT polymer nanocomposite thin films prepared by electrochemical polymerization

Abstract

Hydrogen sulfide (H2S) gas sensors in the form of thin films based on polyaniline (PAN) incorporated with various concentrations of functionalized single wall carbon nanotubes (f-SWCNT) were prepared by electrochemical polymerization of Aniline monomer with sulfuric acid in an aqueous solution. Surface morphology of the thin film nanocomposites was investigated by Field Emission Scanning Electron Microscopy (FE-SEM) and revealed that the f-SWCNTs were almost uniformly distributed on the surface of the host PANI matrix. The X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Hall effect measurements were used to characterize the synthesized PANI/f-SWCNT nanocomposites. The Hall measurements reveal the p-type conductivity. The grown FTIR band at 1145 cm−1 with the increase of the f-SWCNT content evidence a formation of charge transfers due to a remarkable interaction between PANI and f-SWCNTs. The response of this nanocomposite film towards the H2S gas was investigated by monitoring the change in the electrical resistance with the time in the presence of 30% H2S at different operating temperatures. The sensing analysis showed that the sensitivity increased with f-SWCNT content in the PANI matrix. The rapid response/recovery times toward the H2S gas, at 50 °C, was achieved for a PANI/0.01% f-SWCNT nanocomposite sample. Keywords: Conductive polymer, PANI, Nanocomposites, f-SWCNT, H2S gas sensor