One-step preparation of hierarchical superparamagnetic iron oxide/graphene composites via hydrothermal method

In this paper, graphene/magnetite composites with hierarchical Fe3O4 structures were synthesized via a one-step hydrothermal method. The size of Fe3O4 nanocrystals and nanocrystal clusters can easily be controlled by altering reaction time and the starting mixed solvent ratio, respectively. Raman measurements evidenced that graphene oxide was simultaneously reduced to graphene during the deposition of magnetite particles. The deposition of Fe3O4 nanocrystals and nanocrystal clusters impedes graphene to restore the graphite structure. The composites showed a high crystallinity of magnetite and a considerable saturation magnetization. Furthermore, the acrylate modified Fe3O4 makes the composites water-dispersible and can effectively load polyfluorene polyelectrolyte via electrostatic force. The high magnetism, excellent water dispersibility and strong photoluminescence make these composites ideal candidates for various important applications such as magnetic resonance imaging, bioseparation, bioimaging, and optical devices fabrication.

Graphene/magnetite composites with tunable size of Fe3O4 nanocrystals or nanocrystal clusters were synthesized via a one-step hydrothermal method. The size of the Fe3O4 nanocrystal and nanocrystal clusters can be easily controlled by altering reaction time and the starting mixed solvents ratio, respectively. Furthermore, Fe3O4 particles make the composites water-dispersible and can effectively load polyfluorene polyelectrolyte via electrostatic force. High magnetism, strong photoluminescence, and excellent water dispersibility make these composites ideal candidates for various important applications such as drug delivery, bioseparation and magnetic resonance imaging.Highlights► Superparamagnetic Fe3O4 nanocrystals and their clusters were grown on graphene oxide via a one-pot hydrothermal method. ► Size of the magnetite nanocrystals and nanocrystal clusters can be easily tuned. ► Polyacrylate modified Fe3O4 makes graphene-Fe3O4 composites water-dispersible. ► Positively charged polyfluorene polyelectrolyte can be adsorbed onto magnetite particles via electrostatic force. ► Polyfluorene endows interesting fluorescent property to graphene-Fe3O4 composites.