Tuning the magneto-rheological properties of magnetic fluid using hydrophilic fumed silica nanoparticles.

In this work, we study the effect of hydrophilic fumed silica nanoparticles with different mass fractions on the magneto-rheological properties of magnetic fluid, and reveal the mechanism by the coarse-grained molecular dynamics simulation. The magneto-rheological experimental results show that the viscosity of the magnetic fluid with silica nanoparticles will first decrease and then increase (larger than that of the pure magnetic fluid) as the mass fraction of silica nanoparticles increases. We use the molecular dynamics calculations to further explain the influence mechanism of the silica nanoparticles on the magneto-rheological properties of the magnetic fluid. We find that non-magnetic particles will hinder the formation of chains of magnetic particles and shorten the length of the chains under magnetic fields. Our research shows that the magneto-rheological properties of magnetic fluid can be optimized with appropriate hydrophilic fumed silica nanoparticles, which is of great significance in the fields of dynamic seals and microfluidics.