Magnetorheological Fluid Based on Shear-Thinning Organogel and Its Performances

Hydrophilic modified nano-SiO₂ particles were homogeneously mixed into Span oleogel at different mass fractions （1.0%‒10.0%） to prepare shear-thinning organogel. The optimal SiO₂ addition amount （mass fraction） was determined to be 5.0% by rheological tests. The shear-thinning organogel based magnetorheological fluid was fabricated using the optimized organogel and its properties were investigated.. The results show that the shear-thinning organogel based magnetorheological fluid had high yield stress and shear stress under magnetic fields, with only a slight decrease in yield stress observed under conditions of low shear rate and high magnetic field strength, indicating favorable magnetic responsiveness. The shear-thinning organogel based magnetorheological fluid exhibited a broad linear viscoelastic region, indicating that the notable elastic characteristics. Under zero-field conditions, the hysteresis loop area of the shear-thinning organogel based magnetorheological fluid was larger than that of the Span oilgel based magnetorheological fluid, suggesting that the incorporation of non-magnetic components impedes the recovery capability of the field-induced chain-like structures after the removal of the magnetic field. Compared with mineral oil based magnetorheological fluid, the shear-thinning organogel based magnetorheological fluid showed a slightly prolonged response time and a slower magnetic response rate.