Gas sensing characteristics of polyandrie single-wall carbon nanotube composites

Abstract

A composite of polyaniline (PANi) and single-wall carbon nanotubes (SWNTs) is created when aniline and oxidant are added into the acidic medium used for the purification of SWNTs. Raman and FTIR spectra indicate variations in the intensity and shifts in positions of the adsorption bands assigned to the vibration modes standing for PANi. The results are interpreted as being due to modifications in the chemical and the electronic structures of PANi. The addition of SWNTs in PANi enhances the degree of oxidation of emeradine PANi and is considered as a physical doping for PANi conductivity. The presence of SWNTs in the PANi-SWNTs composite alters the polaron and the bipolaron lower levels in the PANi band gap. As a result, PANi-SWNT composites exhibit significantly improved in gas-sensing characteristics.