Reactive wetting enabled anchoring of non-wettable iron oxide in liquid metal for miniature soft robot

Yifeng Shen; Dongdong Jin; Mingming Fu; Sanhu Liu; Zhiwu Xu; Qinghua Cao; Bo Wang; Guoqiang Li; Wenjun Chen; Shaoqin Liu; Xing Ma

doi:10.1038/s41467-023-41920-4

Reactive wetting enabled anchoring of non-wettable iron oxide in liquid metal for miniature soft robot

Nat Commun. 2023 Oct 7;14(1):6276. doi: 10.1038/s41467-023-41920-4.

Authors

Yifeng Shen¹, Dongdong Jin², Mingming Fu¹, Sanhu Liu^{3

4}, Zhiwu Xu^{3

4}, Qinghua Cao⁵, Bo Wang⁵, Guoqiang Li¹, Wenjun Chen¹, Shaoqin Liu⁶, Xing Ma^{7

8

9}

Affiliations

¹ Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
² Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China. jindongdong@hit.edu.cn.
³ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China.
⁴ State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China.
⁵ School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China.
⁶ Key Laboratory of Microsystems and Microstructures Manufacturing, School of Medicine and Health, Harbin Institute of Technology, Harbin, 150080, China.
⁷ Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China. maxing@hit.edu.cn.
⁸ State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China. maxing@hit.edu.cn.
⁹ Key Laboratory of Microsystems and Microstructures Manufacturing, School of Medicine and Health, Harbin Institute of Technology, Harbin, 150080, China. maxing@hit.edu.cn.

Abstract

Magnetic liquid metal (LM) soft robots attract considerable attentions because of distinctive immiscibility, deformability and maneuverability. However, conventional LM composites relying on alloying between LM and metallic magnetic powders suffer from diminished magnetism over time and potential safety risk upon leakage of metallic components. Herein, we report a strategy to composite inert and biocompatible iron oxide (Fe₃O₄) magnetic nanoparticles into eutectic gallium indium LM via reactive wetting mechanism. To address the intrinsic interfacial non-wettability between Fe₃O₄ and LM, a silver intermediate layer was introduced to fuse with indium component into Ag_xIn_y intermetallic compounds, facilitating the anchoring of Fe₃O₄ nanoparticles inside LM with improved magnetic stability. Subsequently, a miniature soft robot was constructed to perform various controllable deformation and locomotion behaviors under actuation of external magnetic field. Finally, practical feasibility of applying LM soft robot in an ex vivo porcine stomach was validated under in-situ monitoring by endoscope and X-ray imaging.

Abstract

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