The key role of reaction temperature on a polyol synthesis of water-dispersible iron oxide nanoparticles

[摘要] The controlled synthesis of water-dispersible iron oxide nanoparticles is essential for biomedical application. For the continuous growth of iron oxide nanoparticles in polyols, it is still unclear how the temperature will affect the controlled synthesis of water-dispersible iron oxide nanoparticles. This work studies the role of reaction temperature on the continuous growth of water-dispersible iron oxide nanoparticles in diethylene glycol (DEG). At the temperature of 235 degrees C and below, the nanoparticle size increases with the increase of temperature. These nanoparticles are highly water dispersible. Interestingly, with the further increase of temperature to the boiling point of DEG (245 degrees C), precipitations are produced during the reaction. The resulted nanoparticles are not stable in an aqueous solution anymore. X-ray Photoelectron Spectroscopy (XPS) analysis is employed to study the surface changes of nanoparticles prepared at different temperatures. The size, crystal structure, and magnetic properties of these nanoparticles are characterized by TEM, DLS, XRD, XPS, FTIR, and SQUID magnetometry. The crystallite sizes from XRD match very well with those by TEM. The nanoparticles consist of a single-grain domain. The crystal structure of the nanoparticles exhibits a magnetite phase. The magnetization properties are studied for the nanoparticle synthesized at different reaction temperatures. The water-dispersible nano particles can be used for potential magnetic resonance imaging which is indicated by their transverse (r(2)) and longitudinal relaxivities (r(1)). The relaxivity properties are consistent with the size of nanoparticles prepared at various temperatures.

[发布日期] 2021-12-15

[关键词] Iron oxide nanoparticle;Temperature;Polyols;Water soluble;Magnetic property;Thermal decomposition