Influence of titanium dioxide nanoparticles on the structural, thermal, electrical properties, and gas sensing behavior of polyaniline/phenothiazine blend nanocomposites

We report the preparation, characterization, and properties of polyaniline (PANI)/phenothiazine (PTZ) blend with different concentration of titanium dioxide (TiO2) nanoparticles. Formation of nanocomposites was monitored by Fourier transform infrared spectra, UV, X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis studies. Spectroscopic characterization confirmed the bonding structure of PANI/PTZ/TiO2 composite through the shift in absorption peaks of nanocomposites compared to pure PANI/PTZ blend. XRD studies confirmed the presence of sharp crystalline peaks of TiO2 in the blend system signifying good interaction among the adjoining molecular chain of polymer with the nanoparticles. Surface morphological details of the nanocomposites obtained using SEM and HR-TEM reveal the formation of hemispherical-like structures with a diameter of 15 to 30 nm. DSC measurements of these nanocomposites showed that the glass transition temperature was reduced as the concentration of TiO2 increased into PANI/PTZ blend matrix. The influence of filler loading on thermal stability showed that the TiO2 enhanced the thermal stability and reduced the rate of thermal degradation of polymer blend nanocomposites. Conductivity studies showed that both AC and DC conductivity, dielectric constant, and dielectric loss increase with an increase in the concentration of nano-filler TiO2 up to 10 wt%. Similarly, the ammonia gas sensing behavior of nanocomposites was also improved by the addition of nanoparticles. From the characterization studies, it can be suggested that TiO2 helps to achieve excellent thermophysical properties, gas sensing, electrical conductivity, and dielectric characteristics for PANI/PTZ blend which can be used in the fabrication of electrical or nano-electronic devices.