Synthesis and Characterization of Polyethylene Glycol Coated Superparamagnetic Fe3O4 Nanoparticles

The purpose of the present study is to synthesize polyethylene glycol (PEG) coated superparamagnetic iron oxide (Fe₃O₄) nanoparticles using a non-toxic, low-temperature, and cost-effective sol-gel method. Fe(NO₃)₃.9H₂O is used as the iron precursor, ethanol as the solvent, and non-toxic triethylamine (TEA) as the gelation agent. Reactions are carried out at a low synthesis temperature of 60°C. The X-ray diffraction (XRD) pattern of the synthesized powder confirmed the magnetite (Fe₃O₄) phase of iron oxide with a cubic inverse spinel structure. Field emission scanning electron microscopy (FE-SEM) results confirmed that the resulting Fe₃O₄ nanoparticles were roughly spherical in shape and monodisperse in nature. Fourier transform infrared spectroscopy (FTIR) results confirmed that the surface of Fe₃O₄ nanoparticles was coated with PEG through carbonyl groups. FTIR results also showed that the intensity of the band related to the coated powder increased with an increase in the concentration of PEG. The quantitative elemental analysis was done by energy-dispersive X-ray spectroscopy (EDAX). Thermo-gravimetric analysis (TGA) confirmed the presence of PEG in the structure of Fe₃O₄ nanoparticles. Results of the vibrating sample magnetometer (VSM) showed that the obtained Fe₃O₄ nanoparticles exhibit excellent superparamagnetic behavior with high saturation magnetization at room temperature. Such superparamagnetic Fe₃O₄ nanoparticles with a favorable size are promising candidates for biomedical applications.