Preparation and Characterization of Silica-Coated Iron Oxide Nanoparticles (Fe3O4@SiO2 NPs)

Abstract

In this study, this SiO₂ has been coated on the surface of Fe₃O₄ (Fe₃O₄@SiO₂) by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) under alkaline medium at 80^oC. It was found that only 500  mL TEOS is required to obtain the best coated Fe₃O₄ core structures which has been confirmed from its TEM micrograph. FTIR analyses revealed the formation of Si-O-Si bonds at 1084.2–1101.4 cm^-1 hence confirmed that SiO₂ has been successfully coated the Fe₃O₄ core. From the FESEM analyses, the average size of silica was ~ 50 -70 nm.  EDX of the Fe₃O₄@SiO₂ showed that silica had been effectively bonded onto the surface of Fe₃O_4. The VSM measurements confirmed the superparamagnetic properties of Fe₃O₄@SiO₂ that is desirable for biomedical applications.