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Peng et al. Soft Sci 2023;3:36 Soft Science
DOI: 10.20517/ss.2023.28

Research Article Open Access

A highly stretchable and sintering-free liquid metal

composite conductor enabled by ferrofluid

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2,#
1
3,*
Maoyu Peng , Biao Ma , Guoqiang Li , Yong Liu , Yang Zhang , Xing Ma , Sheng Yan 1,*
1
Institute for Advanced Study Shenzhen University, Shenzhen 518060, Guangdong, China.
2
State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University,
Nanjing 210096, Jiangsu, China.
3
Sauvage Laboratory for Smart Materials, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, Guangdong, China.
4
School of Engineering, Macquarie University, Sydney, NSW 2109, Australia.
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The authors contributed equally.
* Correspondence to: Prof. Xing Ma, Sauvage Laboratory for Smart Materials, Harbin Institute of Technology (Shenzhen),
Xueyuan Avenue, Shenzhen 518055, Guangdong, China. E-mail: maxing@hit.edu.cn; Prof. Sheng Yan, Institute for Advanced
Study Shenzhen University, Nanhai Road, Shenzhen 518060, Guangdong, China. E-mail: shengyan@szu.edu.cn
How to cite this article: Peng M, Ma B, Li G, Liu Y, Zhang Y, Ma X, Yan S. A highly stretchable and sintering-free liquid metal
composite conductor enabled by ferrofluid. Soft Sci 2023;3:36. https://dx.doi.org/10.20517/ss.2023.28
Received: 20 Jun 2023 First Decision:12 Jul 2023 Revised: 7 Aug 2023 Accepted: 17 Aug 2023 Published: 16 Oct 2023
Academic Editor: Chuanfei Guo Copy Editor: Pei-Yun Wang Production Editor: Pei-Yun Wang
Abstract
Stretchable and highly conductive elastomers with intrinsically deformable liquid metal (LM) fillers exhibit
promising potential in soft electronics, wearables, human-machine interfaces, and soft robotics. However,
conventional LM-elastomer (LME) conductors require a high loading ratio of LM and the post-sintering to rupture
LM particles to achieve electric conductivity, which results in high LM consumption and process complexity. In this
work, we presented a straightforward and post-sintering-free method that utilizes magnetic aggregation to
fabricate stretchable LME conductors. This was achieved by dispersing LM ferrofluid into the elastomer precursor,
followed by applying the magnetic field to induce the aggregation and interconnection of the LM ferrofluid particles
to form conductive pathways. This method not only simplifies the preparation of initially conductive LME but also
reduces the LM loading ratio. The resulting conductive LME composites show high stretchability (up to 650%
strain), high conductance stability, and magnetic responsiveness. The stretchable LME conductors were
demonstrated in various applications, including the creation of flexible microcircuits, a magnetically controlled soft
switch, and a soft hydrogel actuator for grasping tasks. We believe the stretchable LME conductors may find wide
applications in electronic skins, soft sensors, and soft machines.

Keywords: Liquid metal, sintering-free, conductor, ferrofluid

© The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0
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