Solvothermal synthesis of size-controlled monodispersed superparamagnetic iron oxide nanoparticles

Superparamagnetic iron oxide nanoparticles are of great interest in magnetic targeted drug delivery due to their unique properties. In this paper, size-controlled superparamagnetic iron oxide nanoparticles were synthesized in an ethylene glycol/diethylene glycol (EG/DEG) binary solvent system via a facile solvothermal method. X-ray diffraction (XRD), a scanning electron microscope (SEM), and a vibrating sample magnetometer (VSM) were used to confirm that the prepared samples were superparamagnetic Fe₃O₄ nanospheres. When the VEG/VDEG was varied from 100/0 to 80/20, 60/40, and 40/60, the average diameters of the resulting Fe₃O₄ nanospheres were approximately 700, 500, 300, and 100 nm, respectively. In addition, the saturation magnetization (Ms) of Fe₃O₄ nanoparticles with a size of 100, 300, 500, and 700 nm was 72.14, 75.94, 80.28, and 85.41 emu/g, and the corresponding remanent magnetization (Mr) was 3.34, 3.97, 3.26, and 4.28 emu/g, respectively. The relevant formation mechanisms of Fe₃O₄ nanoparticles are proposed at the end. These superparamagnetic Fe₃O₄ nanoparticles with high saturation magnetization may have use as targeted drug carriers.