Surface‐Engineered Liquid Metal Particles for Printing Stretchable Conductive Composites with Enhanced Stability Under Different Strain Rates
Ren‐Mian Chin, Youngshang Han, Mohammad H. Malakooti
Abstract
Abstract Integrating liquid metal (LM) particles into compliant polymers presents an innovative approach for developing intelligent and adaptable systems in stretchable electronics, wearable devices, soft robotics, and other emerging technologies. However, the inherent electrically insulative nature of these solid‐liquid composites, compounded by the gallium oxide shell surrounding LM droplets, poses a significant challenge in establishing conductive pathways, especially for small droplet sizes and ultrasoft elastomers. Here, an interface modification approach that addresses this bottleneck and enables the synthesis of highly stretchable and printable composites with LM microparticles (<2 µm) is presented. Polyvinylpyrrolidone (PVP) is used to functionalize these small LM inclusions, weakening the particle‐matrix interface, and facilitating the formation of a conductive percolating network under tensile strain. Optimized synthesis parameters result in printed conductive traces with excellent electrical conductivity (0.2 Ω cm −1 ), ultra‐high elongation at break (>900% strain), and minimal resistance change (≈131%). Furthermore, this comprehensive study of the electromechanical response of these stretchable conductors under various strain rates reveals their exceptional stability under dynamic loading conditions, surpassing the performance of conductive traces composed of sprayed liquid metal. Finally, the potential application of these multifunctional materials in stretchable circuitry, addressing the demand for high stretchability and stability in wearable electronics, is demonstrated.