Synthesis of hollow magnetite nanoparticles via self-assembly and their magnetorheological properties

Hollow magnetite particles were synthesized in an autoclave using a solvothermal method and adopted as a magnetorheological (MR) material when dispersed in silicone oil. The particle morphology, size, and hollow chamber of these nanoparticles were scrutinized by scanning electron microscope and transmission electron microscope. Their crystal structure, mesoporous structure and magnetic properties were confirmed by X-ray diffraction, nitrogen gas porosimetry measurements, and vibrating sample magnetometry, respectively. Hollow Fe3O4 nanoparticles (10 vol%) were dispersed in silicone oil to fabricate the MR fluid and measure the MR characteristics using a rotational rheometer under various magnetic field strengths. The fabricated MR fluid showed typical Bingham behavior with yield stresses determined from the flow curves.