Lignin-Based Vitrimer for High-Resolution and Full-Component Rapidly Recycled Liquid Metal Printed Circuit

Abstract

Room-temperature liquid metals (RTLMs) exhibit inherent fluidity, metallic conductivity, remarkable stability, and recyclability, which indicate significant potential for applications in improving the efficiency of electronics recycling and reducing costs. However, the low viscosity of RTLMs and their poor interfacial adhesion to substrates typically necessitate the utilization of intricate fabrication processes. Here, a viscosity-tunable, photothermal repairable, and full-component recyclable eutectic gallium–indium/epoxy-modified lignin/polyethylene glycol diacid/ethylene glycol vitrimer (EGaIn-LPEv) is presented for printed circuits. The vitrimer system displays good interfacial stability and tunable viscosity at room temperature because of the ultra-high reactive site content of the modified lignin and the dual dynamic bonding system by the introduction of ethylene glycol. EGaIn-LPEv-based printed circuit exhibits a high resolution and full component recovery of up to 7.6 µm and 98.3 wt.%, respectively. As the principal component, lignin not only enhances the system's green credentials but also endows it with an efficient photothermal repairable capability. The reconnection of a damaged printed circuit can be achieved in 15 s through the utilization of 808 nm infrared activation. This study opens a new avenue for the development of green manufacturing processes and the sustainable application of advanced, high-resolution, and fully recycled electronic devices.