Dynamic Ionic Liquids‐Based Conductive Coatings for Customizable, Integrated and Recyclable Printed Circuit Boards

Abstract Given the pollution and waste of resources caused by electronic waste, the search for recyclable alternatives to printed circuit boards (PCBs) is an attractive approach to alleviating this situation. For the next generation of recyclable integrated PCBs, it is imperative to further consider both the recyclability of the integrated electronics and the appropriate welding technique. Herein, a fully dynamic ionic network based on dynamic ionic liquids and dynamic cross‐linkers is developed as the host of PCBs, while liquid metal droplets, which can be easily recycled, are selected as conductive fillers. By virtue of concentration‐induced polymerization, a conductive coating can be obtained after solvent evaporation, which exhibits outstanding adhesion to multiple substrates. Furthermore, conductive circuits can be customized by activating the conductivity of liquid metal droplets under patterned pressure. The fully dynamic ionic network can also function as versatile electronics that can be easily integrated into PCBs through healing welding. It demonstrates the ability to provide 2D imaging of pressure and temperature distributions. Owing to the multiple stimulation responses of the abundant disulfide bonds, the fully dynamic ionic network exhibits intrinsic recyclability, and the disulfide bonds can also be degraded by reducing reagents to achieve the recycling of the embedded liquid metal.