Effect of Nanoparticle Content on the Magnetic, Thermal, and Optical Properties of CoFe2O4/PVP Nanocomposites

Polyvinyl pyrrolidone (PVP) is widely used due to its solubility, film-forming ability, and biocompatibility. However, its low thermal stability and lack of magnetic properties limit its use in high-temperature and magnetic-field-responsive applications. To overcome these drawbacks, cobalt ferrite (CoFe₂O₄)/PVP nanocomposites were synthesized with varying filler contents (0.5, 2, and 3 wt.%) using a conventional casting method. The materials were characterized by X-ray diffraction (XRD), field- emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and UV-Vis spectroscopy. XRD confirmed the spinel structure with an average crystallite size of 38.9 nm. FESEM showed nanoparticles (~ 42.1 nm) dispersed within the PVP matrix, with slight agglomeration. TGA revealed enhanced thermal stability at higher filler contents, indicated by increased degradation temperatures and char yield. VSM measurements demonstrated improved magnetization with increasing CoFe₂O₄ content. UV-Vis spectroscopy showed a reduction in optical bandgap from 3.75 eV (pure PVP) to 2.32 eV (3 wt.% nanocomposite), attributed to quantum confinement and interfacial interactions. These findings confirm that incorporating CoFe₂O₄ nanoparticles into PVP effectively enhances its thermal, magnetic, and optical properties, broadening its potential for advanced functional applications.