Abstract:

In this work, structural, magnetic and self-heating characterizations of Fe3O4 nanoparticles coated with PEG polymer with different molecular weight, are investigated. The structural analysis showed that all the prepared powders are polycrystalline in nature with cubic spinel structure. The recorded Fourier- transform infrared spectroscopy spectra are characterized by two strong bands ascribed to the spinel structure of Fe3O4 structure, in addition of the appearance of new bands after coating with PEG.

The room temperature magnetic characterization shows that the magnetic behaviour of Fe3O4 nanoparticles coated with PEG is purely superparamagnetic dominated by a paramagnetic behaviour. Particle size analysis showed that the average magnetic particle sizes in all system examined wers 8.5nm, which indicate that coating did not affect the particles magnetic sizes.

For hyperthermia application, self-heating measurements of Fe3O4nanoparticles coated with PEG have been carried out by varying the frequency and the concentration of NPs. Temperature vs time curves are recorded, and from the slope, the SAR values are estimated. It is found that the maximum temperature achieved within the first 10 min and the best driving frequency was at 331kHz. Analysis for the relaxation time using Brownian model gave that the average hydrodynamic particle sizes is 21nm, which is larger than the magnetic size as expected. The obtained values of SAR are found to be dependent on PEG molecular weight where Fe3O4@PEG(400) NPs exhibits the best performance and can be considered as the most promising NPs system for hyperthermia achieving a maximum temperature rise of 43.8°C and SAR value of 26.1 at driving frequency of 331kHz.