Highly dispersible Fe3O4 nanoparticles via anionic surface modification

Abstract

The dispersibility in an aqueous solution of magnetite nanoparticles was enhanced by appropriate anionic surface treatment. The Fe3O4 nanoparticles were modified with various types of the precursor to include anionic terminal functional groups. The nanoparticles modified by polyacrylic acid, tri-sodium citrate dihydrate or ammonia exhibited an increased zeta potential owing to the large amount of terminal hydroxyl and carboxyl groups. As a result, the surface-modified particles exhibited improved dispersion behaviour in the aqueous solution owing to a change in the electrostatic force due to the surface charge on each particle. In addition, the physical properties of the surface-modified magnetite nanoparticles were discussed.