Iron magnetic nanoparticles coated with different loadings of polyvinylpyrrolidone: Evaluation of magnetic properties and morphology

Polyvinylpyrrolidone-coated iron magnetic nanoparticles (PVP-Fe MNPs) have proven to be useful materials for several applications. However, the relationship between the PVP loading and the properties of these materials is not currently well understood. In this study, we examine the changes in the magnetic properties and morphology of PVP-Fe MNPs as a result of varying the PVP loading. The samples were synthesised by a co-precipitation technique in a homogeneous solution containing PVP and iron salts. Fourier transform infrared spectroscopy (FTIR) indicates the presence of PVP on the surface of the core-Fe MNPs. Meanwhile, vibrating sample magnetometer (VSM) reveals that the PVP loading had an inverse relationship with the magnetic properties (saturation magnetisation, Ms, remanence magnetisation, Mr and coercivity, Hc), which was mainly impacted by the morphology of the resultant PVP-Fe MNPs. Thermogravimetric (TGA) and carbon and nitrogen elemental analyses were used to characterise the proportion of PVP bound to Fe-MNPs. The results suggest that the properties of these PVP-Fe MNPs can be tuned by the PVP loading used in their synthesis, allowing these materials to be tailored for the targeted application.