Magneto-soft robots based on multi-materials optimizing and heat-assisted in-situ magnetic domains programming

Soft robots, inspired by the flexibility and versatility of biological organisms, have potential in a variety of applications. Recent advancements in magneto-soft robots have demonstrated their abilities to achieve precise remote control through magnetic fields, enabling multi-modal locomotion and complex manipulation tasks. Nonetheless, two main hurdles must be overcome to advance the field: developing a multi-component substrate with embedded magnetic particles to ensure the requisite flexibility and responsiveness, and devising a cost-effective, straightforward method to program three-dimensional distributed magnetic domains without complex processing and expensive machinery. Here, we introduce a cost-effective and simple heat-assisted in-situ integrated molding fabrication method for creating magnetically driven soft robots with three-dimensional programmable magnetic domains. By synthesizing a composite material with neodymium-iron-boron (NdFeB) particles embedded in a polydimethylsiloxane (PDMS) and Ecoflex matrix (PDMS:Ecoflex = 1:2 mass ratio, 50% magnetic particle concentration), we achieved an optimized balance of flexibility, strength, and magnetic responsiveness. The proposed heat-assisted in-situ magnetic domains programming technique, performed at an experimentally optimized temperature of 120 °C, resulted in a 2 times magnetization strength (9.5 mT) compared to that at 20 °C (4.8 mT), reaching a saturation level comparable to a commercial magnetizer. We demonstrated the versatility of our approach through the fabrication of six kinds of robots, including two kinds of two-dimensional patterned soft robots (2D-PSR), a circular six-pole domain distribution magnetic robot (2D-CSPDMR), a quadrupedal walking magnetic soft robot (QWMSR), an object manipulation robot (OMR), and a hollow thin-walled spherical magneto-soft robot (HTWSMSR). The proposed method provides a practical solution to create highly responsive and adaptable magneto-soft robots.