Effects of the concentration of tetramethylammonium hydroxide peptizer on the synthesis of Fe3O4/SiO2 core/shell nanoparticles

Different amounts of tetramethylammonium hydroxide (TMA) were employed to peptize the Fe3O4 magnetic nanoparticles. Electrophoresis measurements show that the stability of the magnetic nanoparticles is dependent on the amount of TMA used. After growth of the silica protection layer on the nanoparticle surface, Fe3O4/SiO2 composite core/shell particles with different number of cores were synthesized. Under the optimal amount of TMA used, uniform Fe3O4/SiO2 composite core/shell nanoparticles with a poly-dispersivity of 10.8% were prepared.