In-situ self-assembled polyaniline/carbon nanotubes nanofiber thin films for ammonia gas sensors

Abstract

Polyaniline/carbon nanotubes (PANI/CNTs) nanocomposite thin films were fabricated through an in-situ self-assembled method on the interdigitated electrodes for ammonia (NH3) gas sensors. CNTs presented in this work consisted of singlewalled CNTs (SWNT) and multi-walled CNTs (MWNT). The pure MWNT dispersed in N,N-Dimethyl Formamide (DMF) solution was also dipped on the interdigitated electrodes for gas-sensing property comparison. The SEM images showed clearly that PANI/CNTs nanocomposite thin films possess a nanofiber mesh like structure, and TEM analysis exhibited that the diameter of the pure MWNT was 10 nm whereas that of the PANI/MWNT nanofiber was about 50 nm, which confirmed a PANI layer packed on the surface of MWNT during the in-situ polymerization process. The gasresponse of different sensing films to NH3 was investigated at room temperature. It was found that PANI/MWNT nanocomposite thin film exhibited the higher sensitivity than pure MWNT film and PANI/SWNT thin film, which might be ascribed to more active sites for gas adsorption for the PANI/MWNT nanocomposite thin film. The response-recovery property was studied when the PANI/MWNT thin film sensor was exposed to different concentrations of NH3 ranging from 23 to 141 ppm, and it was found that the sensitivity was linear to the concentrations of NH3. This sensor also had good reproducibility and selectivity.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.