Abstract
Discovering the relationship of structure and rheological behaviors remains challenging. In this study, the TiO2 nanoparticle decorated magnetic MoS2 nanosheets (Fe3O4@MoS2@TiO2 nanoparticles) exhibited unique rheological behaviors under external electric and magnetic fields owing to their special hierarchical structures. The constructed core–shell structures of the Fe3O4@MoS2@TiO2 nanoparticles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The magnetic behaviors were studied using a vibrating sample magnetometer (VSM). The Fe3O4@MoS2@TiO2 nanoparticles exhibited both electrorheological (ER) and magnetorheological (MR) properties that result from the decoration of high dielectric TiO2 nanoparticles on the MoS2 shell and paramagnetic behavior of Fe3O4 nanoparticles in the core, respectively. The MoS2 nanosheets act as superb lubricant at a high shear rate due to their weak interlayer van der Waals forces. The abrupt decrease of shear stress at a critical shear rate was observed under the external magnetic field and the proposed mechanism was also discussed. The unique rheological behaviors of the Fe3O4@MoS2@TiO2 nanoparticle based suspensions highlight the great promise of MoS2-based materials for cornerstone applications in rheological fields.