The paper highlights the application of a permeable superelastic liquid-metal fibre mat in biocompatible and monolithic stretchable electronics. As we are moving toward a technologically immersive world, electronics that are being worn on different parts of the body and interacting with humans are becoming an emerging trend. These kinds of “wearable” electronics have found promising applications in electronic skin (E-skin), medical and healthcare monitoring, sports tracking, and physiotherapy. However, conventional electronics are rigid, inextensible, flat, and fabricated with impermeable materials, whereas humans are soft, stretchable, and have contours, and therefore highly require a microenvironment that provides sufficient permeability to air, moisture, and liquid. As such, existing solid electronics may impede wear comfort and even create skin inflammation over long-term wear, which may further limit the design form factors of wearable and on-skin electronics.
Stretchable electronic circuits printed on permeable superelastic liquid-metal fiber mat.
To overcome this challenge, this research work replaces conventional solid and impermeable electronic materials with soft, superplastic, and breathable electronic materials. A new type of stretchable conductor, named a liquid-metal fiber mat (LMFM), is fabricated by simply coating or printing liquid metal onto an electrospun elastomeric fiber mat. In this LMFM, liquid metal hangs among the elastomeric fibres and self-organizes into a mesh-like and buckled structure, which can simultaneously offer high permeability, stretchability, conductivity, and electrical stability. The newly developed LMFM demonstrates smart adaptiveness to omnidirectional stretching over a 1800% strain, and most importantly, good biocompatibility with human skin. The paper also demonstrates that LMFM can be a versatile and user-friendly platform to fabricate monolithic stretchable electronics that provide high integration density, multifunctionality, and long-term wearability. This novel stretchable conductor is expected to find remarkable applications in wearable and on-skin electronics, soft robotics, and bioelectronics.
The study was done in collaboration with Dr. Yang Chai of the Department of Applied Physics and Dr. Xin Zhao of the Department of Biomedical Engineering at PolyU.
Ma Z, Huang Q, Xu Q, Zhuang Q, Zhao X, Yang Y, Qiu H, Yang Z, Wang C, Chai Y, Zheng Z.* Permeable superelastic liquid-metal fibre mat enables biocompatible and monolithic stretchable electronics. Nat Mater. 2021 Feb 18. doi: 10.1038/s41563-020-00902-3.