Coaxial 3D-Printed and kirigami-inspired deployable wearable electronics for complex body surfaces

Abstract Wearable electronics used to capture biological signals are substantially important in human–robot interactions, health monitoring, and clinical treatment. However, for curved or irregular body surfaces, intimate interfacing with the skin, which is essential for robust signal recording, is challenging. In this study, flexible core-sheath fiber sensors and adaptive devices were developed using a coaxial 3D printing technique and kirigami-inspired patterns. The printed core-sheath fiber, which was successfully applied in human–robot interaction, exhibited excellent electromechanical properties with a sensing strain range of 700%, and had high accuracy of approximately 3 mN and high electromechanical durability. In addition, the viscoelastic nature of the core material (shear-stiffening gel) provided the fiber array with fine energy dissipation performance against external harm by buffering the impact force by 51% while simultaneously capturing the dynamic impact in 4 ms. Moreover, the introduction of kirigami-inspired deformability to planar electronics facilitated conformable attachment of sensing devices with substantial adjustability to 3D curved surfaces; they can be adapted to shoe pads of different sizes without compromising their sensitivity. The 3D printing technique and kirigami-inspired pattern designs for creating adaptive and flexible wearable electronics hold great potential for advanced health monitoring of diverse and complex epidermal surfaces.