Nanocomposite polyaniline (PANI) films with embedded TiO2 nanoparticles were prepared by electrochemical polymerization of aniline with titania added into the solution. The films were prepared for gas sensing applications. Their morphology and electrical resistivity were controlled by voltammetric parameters and aniline concentration. We found that the bottom auxiliary PANI film prepared by chemical polymerization in order to bridge the insulating gaps between the digits of interdigitated electrodes could be omitted because the nanocomposite film grew even in the gaps at certain monomer concentrations. The morphology and structure of the nanocomposites were studied by scanning and transmission electron microscopy, infrared spectroscopy and X-ray diffraction. FTIR spectra revealed the existence of chemical bonding between the nanoparticles and polymer chains. The films were tested for sensitivity to ammonia. We found that due to titania the sensitivity of the composite film increased two times reaching a 500% change in resistance at application of 100 ppm of ammonia.
TEM plane-view image of a PANI-TiO2 nanocomposite film prepared by electrochemical polymerization of aniline with TiO2 nanoparticles added to the solution.