Microrobots with Programmable Three-dimensional Magnetizations and Motions

Flexible magnetic small-scale robots use patterned magnetization to achieve fast transformation into complex three-dimensional shapes, and thereby achieve locomotion capabilities and functions. These capabilities address current challenges for microrobots such as drug delivery, object manipulation, and minimally invasive procedures. However, possible design options are limited by the existing capabilities of patterning magnetic particles in flexible materials. Here, we report a method for patterning hard magnetic microparticles in an elastomer matrix. This method, based on UV-lithography, uses controlled reorientation of magnetic particles and selective exposure to UV light to encode magnetic particles in planar materials with arbitrary orientation with a geometrical feature size as small as 100 µm. The patterned 3D magnetization profile allows higher-order and multi-axis bending, large-angle bending, and combined bending and torsion in one sheet of polymer, creating previously unachievable shape changes and micro-robotic locomotion mechanisms such as multi-arm power grasping and multi-legged crawling.M.A.S