Two-Dimensional rGO-MoS₂ Hybrid Additives for High-Performance Magnetorheological Fluid

Magnetorheological fluids (MRF) that undergo a change in their viscoelastic properties under the magnetic fields have been considered as one of most important smart functional materials for vibration dampers and shock absorbers in several engineering applications. However, the use of magnetorheological fluids in practical applications has been limited by poor sedimentation ratio and on-state yield stress. Herein, we report hybrid rGO-MoS₂ additives for a high-performance magnetorheological fluid. Two different kinds of hybrid additives, which are called non-magnetic rGO-MoS₂ and magnetic Fe-rGO-MoS₂, were synthesized by using a hydrothermal method. The rGO-MoS₂ added suspensions remained stable for the first 90 min whereas the CIP MRFs settled down quickly (65%) in the first 10 minutes. The Fe-rGO-MoS₂ additives showed a 24% higher on-state shear stress as compared to CIP MRFs. On the other hand, an increase of 60% in the on-state yield stress for Fe-rGO-MoS₂ MRF can be attributed to the gap-filling by the hybrid additives during columnar-structure formation. Among two-dimensional (2D) materials, Molybdenum Disulphide (MoS₂) is a member of transition metal dichalcogenides (TMDCs), traditionally used as solid lubricant, while reduced graphene-oxide (rGO) is a well-known 2D material with supreme mechanical properties. We believe that this study will blaze the new way for developing a high-performance magnetorheological fluids based on various 2D material hybrids.