Recently, Wen Ziqi, a postgraduate of class 2022 from School of Optical-electrical and Computer Engineering published the latest research paper in Journal of Materials Chemistry C. The research reported the stretchable conductive fibres which are of great academic significance and practical value, considered as the cover paper of the issue. The research was finished by Wen from the Ultra-precision Optical Manufacture Innovation Team led by Academician Zhuang Songlin as well as other four writers such as Zhou Jingyu, Zhao Shanshan from School of Optical-electrical and Computer Engineering, Chen Shangbi, associate director of Shanghai Academy of Spaceflight Technology, and Professor Zhang Dawei; Dr. Sheng Bin was the corresponding author.
Flexible electronics hold great potential for use in the fields of artificial intelligence, health monitoring, and sports tracking, wherein they are incorporated in wearable electronics, 1–8 electronic skin, 9–13 and soft robots. 14,15 The core parts of the above electronics are usually flexible, stretchable, and lightweight sensors and conductors in various forms. 16–30 Flexible fibres with excellent properties are suitable for wearable devices and have attracted extensive research attention as they can be easily woven into clothes or gloves. Numerous innovative studies on such fibres have been reported, for applications as supercapacitors,31–35 stretchable wires,36–38 and strain sensors.39–42 However, challenges remain in synthesising innovative materials using simple fabrication methods.
Stretchable conductive fibres show great potential in the field of wearable and flexible electronics, with multifunctional conductive fibres being of particular interest. In this study, a conductive thermoplastic polyurethane (TPU) wire@eutectic-gallium–indium (EGaIn)/TPU (TET) fibre comprising a TPU wire core and EGaIn-based polymer sheath is developed, wherein the fibre obtained via a simple dip coating method realized high conductivity after mechanical sintering and particle size optimization of EGaIn. As a resistance-type strain sensor, the TET fibre responds to various strain states and monitors the behavior of various parts of the body continuously. The TET fibre can be easily deformed into a stretchable helical electrode at a suitable thermoplastic temperature, and maintains its electrical signal stability at ultra-large strain by adjusting the helical index to realize an ultra-high quality factor (Q) value (6691 at a strain of 2000% with a helical index of 7). Moreover, the TET fibre can be easily integrated with fabrics to generate an emergency underwater SOS signal. Remarkably, the valuable EGaIn in the TET fibres can be recycled at a yield of 94.8% and reused. Overall, the TET fibre exhibits great potential for application in flexible and recyclable human motion detectors, stretchable wires, and electronic textiles.