Synthesis, Characterization, Conductivity and Gas Sensing Application of Poly(diphenylamine)/Nickel Oxide Nanocomposites

The effect of nickel oxide (NiO) nanoparticles on the structural, morphological, thermal, dielectric and electrical properties of poly(diphenylamine) (PDPA) was investigated. The Fourier transform infrared (FTIR) studies showed the characteristic absorption bands of nanoparticles at 445 cm −1 , indicating the successful polymerization of diphenylamine with NiO nanoparticles. The X-ray diffraction (XRD) analysis manifests the enhanced crystallinity of PDPA/NiO nanocomposites. The uniform dispersion of NiO nanoparticles within the polymer matrix was confirmed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) images. The inclusion of NiO nanoparticles in the PDPA matrix was demonstrated by energy dispersive X-ray (EDX) and elemental mapping studies. Thermogravimetric analysis (TGA) reveals the superior thermal stability of nanocomposites and thermal activation energy obtained from the Coats-Redfern method confirms this observation. The addition of NiO nanoparticles to PDPA improved the dielectric permittivity, dielectric loss tangent, and AC conductivity of nanocomposites. The room-temperature ammonia gas-sensing properties of the synthesized nanocomposites were examined by monitoring the change in electrical resistance upon ammonia gas exposure. The findings indicated that the composite with a 7-weight percent sample had the best ammonia gas detection performance. The outstanding properties of these nanocomposites open up new possibilities for developing gas sensors and nano-electronic devices.