Synthesis and humidity sensing characteristics of polyaniline/BaTiO ₃ composites

An attempt has been made towards the synthesis of polyaniline/BaTiO3 (PANI-BTO) composite with an objective to examine the possibility of using this composite for humidity sensing. In this work, PANI-BTO composites were synthesized by an in situ chemical oxidative polymerization of aniline in presence of BaTiO3 particles. These composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The electrolyte pH significantly affects the synthesis of PAN l-BTO composite. At lower pH, the formation of BaSO4 was observed in the composite which may be due to the leaching of Ba2 ions from the surface of BaTiO3 particles in HCI medium. The exclusive formation of PANIBTO composite without BaSO4 was achieved at higher pH (5.7). The PANI-BTO composites show better sensing properties than pure PANI, such as higher response factor and quicker response. The composites with 50 wt% of BaTiO3 exhibit an exponential relationship between the resistance and RH irrespective of electrolyte pH used for the synthesis.