Magnetite nanoparticles with controlled sizes via thermal degradation of optimized PVA/Fe(III) complexes

Abstract

In this manuscript, magnetite nanoparticles have been synthesized via an optimized method that consists in the thermal degradation of a polymer-metal complex prepared from an appropriated mix of polyvinyl alcohol and iron nitrate. Negatively charged (Zeta potential) nanoparticles, with a cubic spinel structure (▪ space group) and a narrow size distribution (mean particle size close to 5 nm) were successfully processed. Magnetic characterizations reveal a single-domain superparamagnetic-like behavior with a decreased saturation magnetization (11 emu/g) due to surface effects. Nanoparticle dispersions were investigated by SAXS (hard spheres, Beaucage model) and the average gyration radius (2.1 nm) and Porod’s length (2.4 nm) are found to be close to the nanoparticle’s physical and magnetic sizes. The results revealed that this easy, reproducible and cheap method is suitable to synthesize high-quality single-domain magnetite nanoparticles that can be functionalized for future biological applications.