Surfactant free solvothermal synthesis of monodispersed 3D hierarchical Fe3O4 microspheres

• The Fe3O4 nanoparticles were synthesized by the solvothermal method.
• Monodispersed 3D hierarchical microspheres were obtained.
• The shape and size of nanoparticles were controlled by changing the precursor ratio.
• The nanoparticles have a saturation magnetization of 54 emu/g.
• All the Fe3O4 nanoparticles will be used for potential biological applications.

A solvothermal process was used to prepare highly monodispersed 3D hierarchical Fe3O4 microspheres with spinel structure by exploring triethylene glycol as solvent. The shape and size of the magnetic nanoparticles were controlled by adjusting the concentrations of precursor with invariable base medium. The resulting Fe3O4 samples were phase pure and of hierarchical microspheres consisting of the nanospheres. On the basis of the characterization results, the research proposes a possible process for the growth of hierarchical microspheres. Moreover, the magnetic properties confirm its superparamagnetic behavior. These 3D hierarchical Fe3O4 microspheres can be promising for targeted drug delivery (bio-magnetic) applications.