Fabricating liquid metal flexible stretchable electronics via the composite paper-based stamp transfer

Abstract The high-performance fabrication of flexible and stretchable electronic devices imposes new requirements on both conductive materials and processing techniques. Liquid metal has high conductivity and mechanical stability on stretchable substrates, thus is an excellent candidate for conductive material. However, conventional liquid metal circuit fabrication methods—such as direct printing, template printing, and microchannel injection—face challenges in terms of conformability to curved surfaces and process simplicity. In this study, a composite paper-based stamp transfer technique was proposed, offering advantages including lightweight and thin stamp structures, simple operation, reusability, and low cost. By employing laser engraving to construct microstructured paper stamps and exploiting the adhesion contrast of liquid metal on different surfaces, high-fidelity transfer of circuit patterns onto arbitrary curved substrates is achieved. Experimental results demonstrate that the fabricated liquid metal circuits achieve a minimum linewidth of 200 μ m and a height of approximately 30 μ m, exhibiting excellent electrical continuity and mechanical stability. In addition, a polyvinyl pyrrolidone (PVP) coating with a mass fraction of 5% was introduced to form an elastic, impermeable barrier, suppressing resistance drift and preventing oxide-induced path narrowing during cyclic strain. After encapsulation with a PVP coating with a mass fraction of 5% coating, the circuits maintain electrical conductivity after 100 tensile cycles and can withstand up to 100% tensile strain. Based on this process, multifunctional devices such as flexible proximity sensors, stretchable strain sensors, and wearable heaters have been successfully fabricated, all demonstrating high sensitivity and operational stability. This work provides a universal and efficient approach for the low-cost, high-reliability fabrication of liquid metal-based flexible and stretchable electronics, is of significant theoretical and practical implications for the advancement of flexible electronic manufacturing technologies.