Comparison of Long-Term Atmospheric Aging between <i>Fe</i> ₃ <i>O</i> ₄ and PEG-Protected <i>Fe</i> ₃ <i>O</i> ₄ Nanoparticles

Magnetic nanoparticles have attracted significant attention due to their broad range of applications. A considerable amount of research has been conducted on the oxidation of Fe₃O₄ nanoparticles; however, there remains a significant lack of systematic data on the long-term oxidation mechanisms of these nanoparticles under ambient atmospheric conditions. A comprehensive one-year study was conducted to investigate the magnetic properties of uncoated and PEG-coated Fe₃O₄ nanoparticles. The systematic magnetization versus magnetic field measurements were performed over one year, with the samples stored under ambient atmospheric conditions and measured at regular intervals of a few weeks. To further characterize the synthesized nanoparticles, XRD, FTIR, and DLS analyses were conducted. The time-dependent oxidation process was modeled using an exponential function, and the fitting parameters were analyzed to provide physical insight into the oxidation behavior. The findings offer valuable perspectives on the potential applications of Fe₃O₄ nanoparticles, particularly in magnetically driven technologies across various fields, while also providing a deeper understanding of the slow oxidation mechanisms of uncoated and PEG-coated Fe₃O₄ nanoparticles.