(423j) The Motion of Magnetic Oblate Spheroids Suspended in Newtonian Fluids Under Magnetic Fields

Anisotropic structures are found in many natural materials. People are committed to developing materials that contain aligned anisotropic particles. In this study, we used a rotating magnetic field to align magnetic microdisks. Both rotational and translational motions of particles and different structures of particles are observed. We have developed an analytic solution that describes the alignment dynamics of microdisks. The analytic solution covers the entire possible frequency range of a rotating magnetic field. We also have developed asymptotic solutions at both the high-frequency limit and the low-frequency limit of the rotating magnetic field, which can be easily implemented in industrial applications. Experimental results confirm the theoretical models. We have simulated the translational motion of the microdisks and the formation of different structures that result from induced magnetic fields within the particles. With the knowledge of the dynamics of microdisks suspended in fluids under magnetic fields, we can create composites with anisotropic structures. The three-axis electromagnetic coil system used in this study can align the particles to the desired orientation, and the particles can be frozen inside a solid matrix using a UV-curable polymer.