Preparation of colloidally stable Fe3O4 nanoparticles and its application to the synthesis of Fe3O4-silica composite particles

摘要

Colloidally stable magnetite (Fe3O4) nanoparticles were prepared with a coprecipitation method in the presence of a silane coupling agent of N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TSA), which cationized the surface of Fe3O4 nanoparticles. The dynamic light scattering (DLS) measurements indicated that the Fe3O4 nanoparticles were highly dispersed in nanometer-sizes. Electrophoretic light scattering (ELS) showed that the surface-modified Fe3O4 nanoparticles have positive surface potential. Heterocoagulation between the positive Fe3O4 nanoparticles and the negative silica particles were performed, which produced Fe3O4-silica composite particles with a high monodispersity in particle sizes.