Formation and integration of tunable anisotropic magnetic polymer composites by two stages solidification process

This study exploits a novel two-stage solidification technology to realize anisotropic magnetic polymer composites (MPC, polymer with magnetic powders). The merits of the presented process technology are as follows: (1) magnetic strength of MPC is controlled by weight fraction of magnetic powder, (2) volume of liquid MPC is controlled by pneumatic system, (3) surface of liquid MPC is solidified by UV, and (4) magnetization and solidification of MPC inside the solidified surface. In applications, the polymer-NdFeB composites magnetic structures are realized respectively in liquid and air medium, and further integrate with MEMS structures. The discrete NiFeB-MPC balls (Diameter:500μm-3200μm) with anisotropic magnetization are achieved. Performances enhancement of NiFeB-MPC (30wt%) by anisotropic magnetization during two-stage solidification are: coercivity force (356%), remanence (61%), and saturation magnetization (75%). Assembly of MPC on MEMS structures and the following driving tests are also demonstrated.