Strain engineered 3D magnetic micro actuators with programmed magnetic anisotropy

This work combines programmed magnetic anisotropy and strain engineering in superparamagnetic polymer composites. The proposed approach enables tailored deformation of planar strips into three-dimensional (3D) micro actuators with shape-independent magnetic properties in a single wafer-scale fabrication step. The developed process allows for pattern feature sizes below five μm using a superparamagnetic polymer composite with a particle content of 10 %vol. The feasibility of this approach is demonstrated by fabricating helically shaped swimming microrobots, also known as Artificial Bacterial Flagella (ABF), with shape-independent magnetic properties and diameters as small as 100 μm. The necessity of decoupling the magnetic properties from the shape was confirmed by demonstrating that only ABFs with programmed anisotropy, i.e. shape-independent magnetic properties, are capable of performing desirable locomotion patterns.