Surface acoustic wave-assisted printing of complex three-dimensional magnetic impeller for motion control

Magnetic components are widely utilized in soft robotics, their precise geometry and strong magnetic responsiveness are generally essential. The fabrication of magnetic components is technically challenging, conventional fabrication methods struggle to simultaneously achieve complex structures and programmable patterning of embedded magnetic fillers. Herein, an approach using surface acoustic wave (SAW)-induced magnetic microparticle’s patterning and stepwise layered photopolymerization is presented for the printing of complex magnetic components. By dynamically adjusting photocuring region, complex magnetic components like magnetic impeller with spatially controlled magnetic particles’ arrangement and magnetic-moment alignment was printed as a function demonstrator. Under rotating magnetic field, the printed impeller exhibited stable combined planar motion with tunable orbital radius and rotational speed, successfully completing a 320 mm trajectory through a maze in 66 s. Additionally, leveraging tailored 3D geometry and programmed magnetic particle alignment, magnetic impeller can achieve the movement along a tube under the propulsion of an axially translating magnetic field, typically at 40 mT magnetic field intensity, stable motion over an axial velocity range of 3.30–23.44 mm/s can be obtained. The results demonstrated that our printing process can be used to print complex magnetic components with the potential for advanced soft robotics applications.