Reversible Wet‐Adhesive and Self‐Healing Conductive Composite Elastomer of Liquid Metal

• Published in: Advanced functional materials 2022-08, Vol.32 (35), p.n/a
• Main Authors: Pei, Danfeng, Yu, Shanyu, Liu, Ping, Wu, Yongpeng, Zhang, Xiaofang, Chen, Yijun, Li, Mingjie, Li, Chaoxu
• Format: Article
• Language: English
• Subjects: Adhesion; Adhesive strength; Adhesives; conductive composite elastomers; Conductors; Elastomers; Electrical resistivity; Electronics; Healing; liquid metal self‐healing; Liquid metals; Materials science; Mechanical properties; Recyclability; Robotics; Wearable technology; wet adhesives
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202204257

Stretchable conductors with the combination of high elasticity and electric conductivity have long been pursued in soft electronics. Liquid metals (LMs), whose mechanical properties match well with the elastomeric matrix, have been successfully applied in soft robotics, electronic skins and wearable devices. But it remains challenging to develop conductive composite elastomers of LMs with reversible adhesion and self‐healing. Herein, EGaIn droplets are uniformly dispersed into elastomer, which contain dynamic disulfide to endow the composite elastomer with thermal processability, recyclability, reversible wet adhesion, and self‐healing. With the EGaIn content of ≥40 vol.%, the resultant composite elastomer shows the electric conductivity of 1.3 × 104 S m−1, self‐healing in 8.0 h, and reversible wet adhesion strength up to 670 kPa after curing for 2.0 h. When serving as conductive adhesive, it can easily adhere to the metal electrode to light up the LED even when stretched to 50%. When serving as self‐adhesive bioelectrode, it can also detect human electromyography signals. Thus, not only may this study provide a new platform of designing self‐adhesive, self‐healing, and conductive composite elastomers of liquid metals, but their reversible wet adhesion and self‐healing also promise the facileness of building damage‐endurable soft electronics and applying to human–machine interfaces. EGaIn droplets are uniformly dispersed into elastomer, which contain dynamic disulfide, catechol groups, and carboxyl groups to endow the composite elastomer with stretchable conductivity (up to 1.3 × 104 S m−1), self‐healing, reversible wet adhesion, and thermal processability. The composite elastomer of LM is an ideal candidate for bioelectronics. When serving as self‐adhesive bioelectrode, it can detect human electromyography signals.