Preparation and characterization of Fe3O4@TiO2 shell on polystyrene beads

Most magnetic composite materials have a serious sedimentation problem because of their large density. When the nanomaterials are combined with magnetic materials, the density would become larger. In this article, polystyrene (PS) beads were used as core to synthesize raspberry-like PS-Fe3O4@TiO2 particles (PFTPs) by a facile method, which could float on the water. The loaded Fe3O4@TiO2 particles were characterized by X-ray diffraction (XRD), which could confirm the anatase phase TiO2 coated on Fe3O4 nanoparticles. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed the presence of acrylic acid in reaction media could effectively tune the morphology of resulting composite particles between core-shell and raspberry-like. The data of Vibrating sample magnetometer (VSM) indicated the change in saturation magnetization before and after TiO2 coated, the introduction of PS could further influence the saturation magnetization of Fe3O4. Lastly, we proved the sedimentation stability of PFTPs via capturing the photographs of them in water and oil.