Russian scientists have improved the properties of magnetic suspensions, which rapidly and reversibly change stiffness under the influence of a field. The development paves the way for "soft" robotics, mimicking the work of biological muscles, the press service of the Russian Academy of Sciences reported.

Magnetorheological fluids consist of iron microparticles suspended in silicone. In a magnetic field, they align along the field lines and transform the composition into a solid-like material. The main drawback is that the particles are heavier than silicone, settle over time, and clump together due to residual magnetization.

Researchers coated the microgranules with a thin shell of silica (SiO2). In a calm state, it acts as a dielectric and non-magnetic spacer, preventing the particles from clumping. Sensitivity to the field was maintained.

The properties were tested on a rheometer in fields up to 1 tesla: viscosity and elasticity increased by several orders of magnitude, and electrical and thermal conductivity also changed. In the future, such compositions will allow for instantaneous changes in the stiffness of shock absorbers and suspensions. Employees of INEOS RAS, ISPM RAS, ITPE RAS, and the Faculty of Physics of Moscow State University participated in the work.