Activation-independent biphasic liquid metal conductor enables multilayer stretchable electronics

Abstract

Liquid metal-based polymer composites are extensively employed in diverse stretchable electronics. Achieving initial conductivity and strain insensitivity typically necessitates activation or sintering. Therefore, the development of a facile, activation-independent stretchable conductor is critical for advancing liquid metal-based polymer composites. However, the mechanisms underlying activation-independent initial conductivity and strain insensitivity in these liquid metal-based conductors remain unclear and require further investigation. Furthermore, antibacterial properties and biocompatibility are essential for strain-insensitive conductors to reduce microbial infection risks and ensure safe interaction with biological tissues. Here, we present the synthesis of a two-component hydrogel-like liquid metal composite slurry without additional conductive components. The resulting solid–liquid biphasic conductor (SLBC), patterned from the slurry, exhibits a network topology with activation-independent initial conductivity (20974 S/cm), strain insensitivity (R/R₀ ≈ 21.12 at 2200 % strain), excellent cyclic stability (over 40,000 cycles), multilayer vertical interconnect accesses (VIA) connectivity, and antibacterial properties and biocompatibility. Additionally, we developed a multilayer stretchable wireless ECG patch that facilitates real-time monitoring of personal states via a deep learning model, demonstrating the reliability, versatility, and practicality of the SLBC.