Effect of ultrasonic treatment on dispersibility of Fe3O4nanoparticles and synthesis of multi-core Fe3O4/SiO2 core/shell nanoparticles

Abstract

Ultrasonic treatment was employed to improve the dispersibility of the Fe₃O₄ nanoparticles dispersed in aqueous solutions. Electrophoresis and XPS spectra indicate that the ultrasonic treatment can induce the generation of chemisorbed hydroxyl groups and the oxidation of Fe²⁺ ions on the surface of the magnetic nanoparticles, thus resulting in improved dispersibility of the magnetic nanoparticles. After growth of silica protection layers on the Fe₃O₄ nanoparticles with different times of ultrasonic treatment, Fe₃O₄/SiO₂ core/shell nanoparticles with different amounts of the magnetic cores were successfully prepared.