Tough soldering for stretchable electronics by small-molecule modulated interfacial assemblies

• Published in: Nature communications Vol. 14; no. 1; p. 7723
• Main Authors: Ai, Liqing, Lin, Weikang, Cao, Chunyan, Li, Pengyu, Wang, Xuejiao, Lv, Dong, Li, Xin, Yang, Zhengbao, Yao, Xi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.11.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1005/1007; 639/301/923/966; 639/638/455/957; Assemblies; Conductivity; Electronic components; Electronics; Fabrication; Humanities and Social Sciences; Integrated circuits; Liquid metals; Metal particles; Microelectronics; Mismatch (electrical); Modulators; multidisciplinary; Polymer matrix composites; Polymers; Recyclability; Science; Science (multidisciplinary); Silicon; Silicon substrates; Soldering; Solders; Stretchability; Thermoforming; Wearable technology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-43574-8

The rapid-developing soft robots and wearable devices require flexible conductive materials to maintain electric functions over a large range of deformations. Considerable efforts are made to develop stretchable conductive materials; little attention is paid to the frequent failures of integrated circuits caused by the interface mismatch of soft substrates and rigid silicon-based microelectronics. Here, we present a stretchable solder with good weldability that can strongly bond with electronic components, benefiting from the hierarchical assemblies of liquid metal particles, small-molecule modulators, and non-covalently crosslinked polymer matrix. Our self-solder shows high conductivity (>2×10 5   S  m −1 ), extreme stretchability (~1000%, and >600% with chip-integrated), and high toughness (~20 MJ m −3 ). Additionally, the dynamic interactions within our solder’s surface and interior enable a range of unique features, including ease of integration, component substitution, and circuit recyclability. With all these features, we demonstrated an application as thermoforming technology for three-dimensional (3D) conformable electronics, showing potential in reducing the complexity of microchip interfacing, as well as scalable fabrication of chip-integrated stretchable circuits and 3D electronics. “The interface mismatch of soft substrates and rigid silicon-based microelectronics frequently causes failures of integrated circuits. Here, the authors develop a stretchable solder based on liquid metal-polymer composites which enables seamless integration of electronic components with soft substrates, showcasing high conductivity and stretchability”.