Role of polyvinyl pyrrolidone as a capping agent in the synthesis of magnetite (Fe₃O₄) nanoparticles

1151-1155Uncapped magnetite (Fe3O4) and magnetite capped with polyvinyl pyrrolidone (PVP) (Fe3O4-PVP) have been synthesized by a rapid, cost effective aqueous precipitation method. The nanoparticles are characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and UV spectroscopy. The role of PVP as a capping agent in the synthesis of magnetite nanoparticles has been investigated. Thermal stability and surface charge of the nanoparticles have been characterized by thermogravimetric analysis, differential scanning calorimetry (DSC) and zeta potential measurements. Results suggest that PVP as a capping agent reduces the grain size, regularizes the shape, and increases the crystallinity of Fe3O4 nanoparticles. Thermal stability and surface charge of Fe3O4-PVP nanoparticles are also significantly higher as compared to the uncapped Fe3O4 nanoparticles. Magnetic characterization by vibrating sample magnetometry of both Fe3O4 and Fe3O4-PVP nanoparticles indicates the superparamagnetic behavior of the nanoparticles