Direct-write printed magnetic-controlled soft robots for non-contact applications

Magnetic soft robots have attracted extensive attention in the fields of biomimetic wireless cable robots, flexible electronic devices, targeted drug delivery, and minimally invasive surgery due to their advantages of remote non-contact control, fast response, good performance, and easy miniaturization. However, the current manufacturing methods and material systems restrict the uniformity, simplicity, and motion capabilities of the magnetic contour of soft robots. Here, we utilized a self-made magnetic composite material ink to direct-write printing magnetic soft robots for non-contact applications. The introduction of a polydimethylsiloxane solution mixed with a neodymium iron boron (NdFeB) magnetic powder/silicone rubber material has modified the rheological properties of the printing ink, resulting in the improved structural integrity and fidelity of the printed samples. The morphology and quality of the magnetic structure are controlled by optimizing the printing process parameters, such as solution ratio, printing layer height, and printing speed. Experimental results showed that the magnetic induction intensity of the dumbbell sample with 50 wt. % NdFeB was 4.57 mT, the fracture elongation was 175%, the mechanical strength was 0.8483 MPa, and the five-cycle fatigue tensile stress–strain curve had a high coincidence. As a demonstration, we printed a controllable magnetic clock and a biomimetic magnetic-controlled flower, showcasing the potential applications in non-contact fields, such as smart healthcare and rescue.