3D-Printed Liquid Metal Interconnects for Stretchable Electronics

Stretchable electronic circuits and systems will be critical for future wearable devices and smart textiles, where existing flexible printed circuit board techniques severely limit conformal deformation. In this paper, we present a scalable fabrication approach for making robust interconnects for stretchable electronics using 3D-printed liquid metal paste. Direct extrusion of the liquid metal paste eliminates the need for expensive lithographic molds while offering improved conductivity over traditional carbon- and metal-based inks. As a proof of concept, we demonstrate a multi-layer stretchable circuit, including both active and passive electronic components. We additionally present highly stretchable strain sensors, demonstrating stable conductivity of the liquid metal paste circuit interconnects with minimal hysteresis over more than 350 cycles at 200% strain. These two devices are combined to demonstrate a printed stretchable strain sensor with integrated readout circuitry.