Abstract:A kind of newly aminated CoFe2O4 nanoparticles were synthesized by grafting process for biomedical applications, which were coated primarily with silicon dioxide(SiO2). The characterizations of aminated SiO2/CoFe2O4(ASCN) and SiO2-coated CoFe2O4(SCN) nanoparticles were investigated using elemental analysis, thermogravimetric analysis(TGA), differential thermal analysis(DTA), infrared spectroscopy(IR), atomic force microscopy(AFM), zeta-potential measurement and vibrating sample magneto-metry(VSM). The AFM micrograph shows that the ASCN nanoparticles are approximately spherical with an average diameter of 30 nm. Based on IR and TGA results, it is suggested that the surface of the SiO2-coated CoFe2O4 nanoparticles are grafted with amino compounds. The elemental analysis also shows the presence of 0.98 mmol/g of organic moieties immobilized on the surface of ASCN nanoparticles. Zeta-potential data of ASCN nanoparticles also reveal that amino compounds are bonded onto the surface of SiO2-coated CoFe2O4 nanoparticles by ether linkage. The magnetic parameters show that ASCN nanoparticles still have good magnetic property.

Key words: cobalt ferrites; nanoparticles; magnet; amination; graft; zeta potential; surface modification