Magnetically tunable distribution pattern of magnetic particles in a micro-particle sedimentation system

Abstract Transport of particles via magnetic gradient forces has received considerable attention in various fields. However, few studies have paid attention to the influence of magnetic inter-particle forces during transport process on the final particle distribution. To explore this issue, this work constructed a micro-particle sedimentation system dominated by gravity and the magnetic inter-particle force. Meanwhile, a simple and novel electromagnetic dual-coil actuation system was developed to generate multiple types of static and dynamic magnetic fields for comparative analysis. It is found that the particle assembly behavior induced by magnetic inter-particle forces can result in the decrease of coverage ratio or distribution uniformity under frequently-used static magnetic fields. Furthermore, it has been confirmed that the dynamic magnetic fields including alternating and step-type fields can be applied to alter the magnetic inter-particle forces and inhibit magnetic assembly, thereby achieving a wealth of distribution patterns of particles at the bottom of a micro-container.