3D Printing of Stretchable, Compressible and Conductive Porous Polyurethane for Soft Robotics

Creating conductive materials that combine mechanical compliance and shape adaptability is a key to the development of integrated soft robots with sensors. Here, we present a new 3D printed porous elastomer that functions both as a gripper and a sensor. It is composed of polyurethane-acrylate and dopamine-methacrylamide sponge that enables metal salt reduction to realize metallization capability. The resulting sponge is conductive, can adapt to objects having various shapes, and can function simultaneously as a sensor and as a structural element. The porous objects are formed by emulsion templating, which yields an interconnected open-cell network that exposes catechol groups throughout the bulk, enabling uniform silver deposition via the embedded redox groups. The resulting metallized porous elastomer shows high stretchability and mechanical resilience while maintaining conductivity under large deformations. During uniaxial tension, it exhibits an initial conductivity of ∼328 S·m⁻¹ that decreases reversibly with strain, remaining stable over 500 cycles at 100% elongation with a gauge factor of ∼3. Leveraging this intrinsic coupling of mechanical and electrical responses, 3D-printed porous meta-materials function as tunable resistors, and a proof-of-concept soft gripper demonstrates simultaneous actuation and sensing. This approach provides a versatile route toward fully 3D-printed, multifunctional soft robotic systems in which the body and the sensor act as a single component, with programmable electromechanical behavior.