Magnetically-induced various recoverable deformation of miagnetic liquid metal marble

We report various recoverable deformation of a magnetic liquid metal marble, a gallium-based liquid metal droplet coated with iron (Fe) particles, by changing mass of the coated Fe particles and applying different shapes of magnetic field. The magnetic liquid metal marble was achieved by coating the liquid metal surface with Fe particles using chemical reaction of hydrochloric acid (HCl). By changing amount of the coated Fe particles, we observed irregular wetting (≥ 4 mg) and conventional wetting (< 4 mg) shape of the ∼ 8 μL magnetic liquid metal marble with an applied magnetic field (∼ 3900 gauss). Additionally, by changing shapes of magnetic field, various deformation of the magnetic liquid metal marble such as rod, triangle, cross, and star shape was obtained. By removing the magnetic field, recovery of the marble was readily obtained. Finally, we investigated deformability of 1.21 ∼ 1.73 ratio and recovery time of 99 ∼ 172 ms with/without magnetic field.