Effects of the conditions of the microemulsion preparation on the properties of Fe3O4 nanoparticles

Abstract

Fe3O4 nanoparticles have been prepared by the microemulsion technique with water as the aqueous phase, n-hexane as the oil phase and Span 80 as the surfactant. The reaction occurred under air, N2 or high temperature and high pressure atmosphere. Particle size can be controlled by the concentration of the reactants dissolved in water, the ratio of water/surfactant and the atmospheric conditions. The particle size is of 6 - 20 nm. They are superparamagnetic with the saturation magnetization of 50 emu/g. Functionalization of the particle surface has been carried out by using a single layer of oleic acid for hydrophilic surface and double layer of oleic acid and sodium dodecyl sulfate for hydrophilic surface to disperse them in non-aqueous and aqueous solvents, respectively. Changing the conditions of the preparation affected to the properties of the product. This technique showed advantages such as simple, small size particles, monodisperse over the coprecipitation methods.