Synthesis, characterization, thermal properties, conductivity and sensor application study of polyaniline/cerium-doped titanium dioxide nanocomposites

This work focuses on the in situ chemical oxidative polymerization of aniline with different contents of cerium-doped titanium dioxide (Ce–TiO₂) nanoparticles for the synthesis of polyaniline (PANI)/metal-doped TiO₂ nanocomposites. The interaction of nanoparticles with PANI segments was characterized by FT-IR, UV, XRD, SEM, DSC, TGA and conductivity studies. The sensitivity of ammonia gas through the fabricated nanocomposite was also evaluated with respect to different contents of nanoparticles. The shift in FT-IR peak and UV absorption bands of nanocomposite with respect to pure PANI was clearly observed from the spectroscopic studies. Results from XRD studies showed the uniform arrangement of nanoparticles within the polymer matrix. SEM analysis showed the uniform structure of nanocomposites with spherically shaped dispersion of metal oxide nanoparticles. DSC studies revealed the increased glass transition and melting temperature of nanocomposites with an increase in the concentration of nanoparticles indicating the strong intermolecular interaction between nanoparticles and the polymer chain. TGA showed a higher thermal stability of nanocomposites than that of pure PANI, and thermal stability increases with the increase in the concentration of nanoparticles. Electrical properties such as AC conductivity, dielectric constant and dielectric loss tangent of nanocomposites were greater than pure PANI, and the magnitude of these properties increased with the loading of nanoparticles. Like AC conductivity, the DC conductivity of nanocomposite increased with the loading of nanoparticles. The maximum electrical conductivity was noted for 7 wt% composite. The ammonia sensing properties of composite were higher than the pristine PANI.