Electrical and optical properties of nickel ferrite/polyaniline nanocomposite

Polyaniline–NiFe(2)O(4) nanocomposites (PANI–NiFe(2)O(4)) with different contents of NiFe(2)O(4) (2.5, 5 and 50 wt%) were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol–gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI) and the composites containing 2.5 and 5 wt% NiFe(2)O(4) showed amorphous structures, while the one with 50 wt% NiFe(2)O(4) showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe(2)O(4) nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe(2)O(4) nanoparticles contents. The electrical conductivity of PANI–NiFe(2)O(4) nanocomposite was found to increase with the rise in NiFe(2)O(4) nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of E(g) = 1.0 for PANI–NiFe(2)O(4) nanocomposite.