Morphology control and texture of Fe3O4 nanoparticle-coated polystyrene microspheres by ethylene glycol in forced hydrolysis reaction

The effects of ethylene glycol (EG) on morphology and texture of the magnetite shell/core polystyrene microspheres produced from a forced hydrolysis reaction of FeCl2 solution were investigated. The morphology of magnetite-shell of synthetic composite spheres was dependent on EG concentration. They changed from large sphere with the shell-thickness of ca. 35 nm to corrugated films with increasing EG concentration in the coating solution accompanying a reduction of their shell-particles size to 10 nm. The magnetite coating on latex is formed by a phase transformation from β-FeOOH to magnetite due to the oxidation from Fe2+ to Fe3+ and adsorption of a lot of Fe2+ ions. The shell magnetite formed with EG was hydro-magnetite with a crystal lattice distortion, and they exhibited a polycrystalline nature. The nanoporous magnetite shell was produced in the presence of EG acting as a templating agent. This paper indicates that good superparamagnetic magnetite particles in shell have been synthesized at 5% EG concentration.