Properties and mechanism of ionic liquid/silicone oil based magnetorheological fluids

ABSTRACT A magnetorheological fluid (MRF) is a smart composite suspension composed of nonmagnetic liquid and soft magnetic particles. Carrier fluids can considerably influence the performance of MRFs; therefore, to investigate the effect of carrier fluids on MRFs, an SO/IL-MRF was prepared by mixing an ionic liquid (IL) with silicone oil (SO) in this study. Three types of MRF samples were prepared for experiments (pure SO, pure IL, and SO/IL). According to the experimental results, the SO/IL-MRF has better sedimentation stability than those based on pure SO and pure IL. Further, three methods were used to determine the shear yield stresses of the MRFs. The SO/IL-MRF achieved a higher shear yield stress than those of the other two because a network structure is formed between the ionic fragments and the molecular chains of the SO in the SO/IL-MRF. This increases the movement resistance of the particles in the carrier fluid, and it is unlike the mechanism of the IL-enhanced MRF. This work provides new ideas for improving the MRF performance. Graphical abstractSO/IL-MRF prepared by mixing ionic liquid with silicone oil exhibited better sedimentation stability and higher shear yield stress. This is because a network structure is formed between the ionic fragments and the molecular chains of the silicone oil, which increases the movement resistance of the particles in the carrier fluid