Rheological performances and enhanced sedimentation stability of mesoporous Fe3O4 nanospheres in magnetorheological fluid

In this study, hierarchically structured mesoporous Fe3O4 nanospheres were synthesized using a solvothermal method and the application of the obtained Fe3O4 nanospheres in magnetorheological (MR) fluid was investigated in detail. The morphology, microstructure and magnetic properties of the as-synthesized Fe3O4 nanospheres were examined through different characterization techniques, such as SEM, TEM, XRD, XPS, BET and SQUID. The results of rheological measurements revealed that the prepared homogeneous MR fluid based on mesoporous Fe3O4 nanospheres showed typical MR performances, exhibiting a rapid and reversible transition from a liquid-like to a solid-like state under the action of an external magnetic field. More importantly, it should be noted that the Fe3O4 nanospheres-based MR fluid demonstrated enhanced a sedimentation stability as compared to that of carbonyl iron (CI) particles-based MR fluid. This finding was probably assigned to the particular mesoporous structure and the decreased density mismatch between two components of MR fluid.