Jingda Tang,Bonan Sun,Qianfeng Yin,Meng Yang,Jian Hu,Tiejun Wang
Magnetic hydrogels have demonstrated great potential in soft robots, drug delivery, and bioengineering, and their functions are usually determined by the deforming capability. However, most magnetic hydrogels are embedded with soft magnetic particles (e.g. Fe3O4), where the magnetic domains cannot be programmed and retained under external magnetic fields. Here, we present a strategy to prepare a microgel-reinforced magnetic hydrogel, embedded with hard magnetic NdFeB particles. These magnetic hydrogels show outstanding mechanical properties (ultimate stretching ratio >15 and fracture toughness >15 000 J m−2) and fast actuation speed under external magnetic fields. We use direct ink writing to fabricate magnetic hydrogels with sophisticated geometry and program their magnetization to achieve complex deformations. Fast, reversible, shape-changing structures have been demonstrated with printed magnetic hydrogels. It is hoped that this material system of hard magnetic hydrogels can open opportunities for wide applications.
Inspired by the efficient swimming capabilities of swordfish, a novel wireless soft swordfish-like robot with programmable magnetization has been developed, integrating direct-ink-writing (DIW) 3D printing and assembly technology. This 20 mm long robot features a streamlined form and magnetically programmable movements, enabling biomimetic locomotion patterns such as straight-line swimming and turning swimming. The robot includes a silicone-based torso (body, abdomen, and pectoral fin) and a crescent-shaped tail fin made from a magnetically programmable polymer embedded with neodymium-iron-boron (NdFeB) particles. The tail fin, fabricated by multi-material alternating printing to achieve a gradient magnetism distribution, is controlled by an external magnetic field to mimic the rapid oscillation of a swordfish's tail, achieving a swimming speed of 0.51 BL/ s. The tail fin's asymmetric oscillation amplitudes, adjusted by magnetic field control, allow the robot to transition seamlessly from high-speed straight swimming to agile turning. The robot can perform tracking swimming along specific planned paths, such as “C” and “Z” shaped trajectories. Potential applications include environmental monitoring and targeted drug release. The multi-material 3D printing technology enhances the robot's efficiency and sensitivity in simulating natural biological movements, extending to the design and development of various flexible devices and soft robots.
危险品化学品经营许可证（带存储）