Study of chemiresistor type CNT doped polyaniline gas sensor

The composite thin films of polyaniline (Pani) with multiwall carbon nanotube (MWNT) and single wall carbon nanotube (SWNT) for hydrogen gas sensing application are presented in this paper. Polyaniline (Pani) was synthesized by chemical oxidative polymerization of aniline using ammonium persulfate in acidic medium. The SWNT and MWNT were doped in Pani in presence of champhor sulfonic acid (CSA) by solution mixing method. Thin films of CNT/Pani composites were prepared by spin coating method. Finally, the response of these composite films for hydrogen gas was evaluated by monitering the change in electrical resistance at room tempeature. It is observed that the SWNT/Pani and MWNT/Pani composite films show a higher response as compare to pure Pani. The structural and optical properties of these composite films have been characterised by X-ray diffraction (XRD) and UV–visible spectroscopy respectively. Surface morphology of these films has also been characterised by optical microscopy.