Voltage-Controllable Magnetic Composite Based on Multifunctional Polyethylene Microparticles

Voltage-controlled electric-dipolar micromagnets embedded in a poly-dimethyl siloxane (PDMS) film were described. The spherical 100 μm bichromal polyethylene particles were made using a spinning disk and the particles were fist oriented by an electric field and then magnetized in an electromagnet. The speed at which the magnetization reduces is found to be a function of the adhesion of the micromagnets to the cavity walls and could be adjusted by changing the amount and nature of the swelling fluid. The electric field not only orients the micromagnets, but also pushes the particles against the cavity wall so that they can adhere. It is also seen that for a particular amplitude of electric field, a smaller fraction of the micromagnets are free to rotate at lower frequencies. The characteristic rotation time depends on the strength of the applied electric field, the viscosity of the fluid, and the electric dipole moment.