Obtaining magnetite nanoparticles by Terathane-based polyol synthesis: Structural, thermal, and magnetic characterization

Magnetite (Fe 3 O 4 ) nanoparticles (NPs) were obtained through polyol synthesis followed by a particle-growth treatment at 260 °C, without external surfactants, to evaluate the method's efficiency for producing magnetic nanoparticles with a well-defined crystalline structure, colloidal stability, and surface functionalization. The NPs were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, thermal analyses, dynamic light scattering, transmission electron microscopy, Mössbauer spectroscopy, and magnetometry. X-ray diffraction confirmed predominant magnetite formation, with a cubic spinel-type structure and an average crystallite size of approximately 16.75 nm. The FTIR and TG/DSC analyses indicated the presence of organic groups derived from Terathane on the nanoparticles' surface, highlighting the polyol's role as a stabilizing agent. No visible sedimentation or macroscopic aggregation was observed in ethanol, THF, or chloroform after 45 days. DLS analysis indicated an average hydrodynamic diameter of 31 nm, while TEM images revealed nearly spherical particles with an average diameter of approximately 10.41 nm. Mössbauer spectroscopy confirmed the predominance of magnetite and indicated magnetic relaxation effects, while magnetometry revealed a magnetically soft response, with a saturation magnetization of 54.91 emu·g −1 , a coercive field of 0.188 kOe, and a remanent magnetization of 12.63 emu·g −1 . Thus, the proposed route proved to be simple and efficient for synthesizing Fe 3 O 4 nanoparticles with promising properties for applications in magnetic colloids, nanocomposites, environmental remediation, and biomedical technologies.