Adaptive 3D printing of moldable conductive polymer composite for highly sensitive soft sensors with a broad working range

Abstract

Conductive putty-like polymer composites have recently received considerable attention in wearable electronics, soft robotics, and energy storage due to their unique electrical and mechanical properties. Their viscoelasticity enables direct 3D printing of intricate, customizable conductive pathways, yet printing in high-viscosity polymer solutions remains challenging. Inspired by clay, we develop a moldable conductive polymer composite (MCPC) with tunable viscoelasticity, shear-thinning behavior, and high conductivity by blending liquid Ecoflex with graphite powders. By extruding MCPC onto liquid Ecoflex of various viscosities, we demonstrate a facile strategy for fabricating soft sensors with spatially controlled conductive pathways. These sensors exhibit a wide strain response (0.05%-150%), high sensitivity (gauge factor >15000), and nearly 100% electrical repeatability over 1000 cycles. They reliably monitor human movement and control robotic hands. Our approach provides a new strategy for fabricating soft sensors with enhanced mechanical and electrical properties, expanding possibilities for next-generation wearable and bio-integrated technologies.