In situ synthesis of polyaniline/Sm-doped TiO2 nanocomposites: evaluation of structural, morphological, conductivity studies and gas sensing applications

Abstract

Polyaniline (PANI)/samarium doped titanium dioxide (Sm-TiO2) nanocomposites were prepared through in situ polymerization of aniline with different contents of Sm-TiO2 nanoparticles. The structure and morphology of the nanocomposites were characterized by FT-IR, UV, XRD, HRTEM, SEM, DSC and TGA. The electrical performances of the nanocomposites were investigated by AC and DC conductivity measurements. The effect of nanoparticles on PANI with the carbon monoxide, ammonia and hydrogen sulphide gas sensing properties were also studied. The results from FTIR and UV show the interaction of nanoparticles with PANI. The XRD study revealed the systematic arrangement of nanoparticles within the polymer matrix. HRTEM and SEM analysis showed the uniform structure of nanocomposites with spherically shaped dispersion of metal oxide nanoparticles. The result from DSC analysis indicated an increase in glass transition and melting temperature of nanocomposites than that of PANI. The higher thermal stability of the nanocomposite by the incorporation of nanoparticles was confirmed from TGA studies. The AC conductivity, dielectric constant and dielectric loss of composites were higher than pure PANI and the magnitude of these properties increased with the loading of nanoparticles. The DC conductivity indicates an increase in conductivity with increase in concentration of nanoparticles. The addition of metal oxide nanoparticles to PANI imparts excellent gas sensitivity to different gas at room temperature. Hence fabricated nanocomposites showed excellent thermal properties along with increased electrical conductivity and gas sensitivity, such type of nanocomposite can be used as a substitute for PANI in electrical or nanoelectronic devices.