Synthesis of Fe3O4 nanoparticles of various size via the polyol method

The superparamagnetic Fe3O4 magnetic nanoparticles have attracted a considerable amount of attention in biomedical fields such as drug delivery, MRI contrast, and hyperthermia treatment. To enable these varied applications of Fe3O4 nanoparticles, it is essential to synthesise them in various sizes, from several nanometres to several hundred nanometres. The synthesis of superparamagnetic Fe3O4 nanoparticles was carried out using the polyol method, which is based on the polar polyol and synthesis was attained via a stepwise phase transformation. The concentration of sodium acetate (NaOAc) used to control the rate of hydrolysis of iron precursor and the molar ratio of the iron precursor and water were controlled to vary the size of Fe3O4 particles. It was found that the particle size decreased as the concentration of NaOAc increased and decreased even more when the molar ratio of the iron precursor was decreased. Particles ranging from 11 nm to 338 nm in size were produced using this method. The correlation between starting materials, particle size, and morphology was thus investigated from these results.