Cure-on-demand 3D printing of complex geometries for enhanced tactile sensing in soft robotics and extended reality

Replicating the tactile sensing mechanisms, conformity, and feel of real skin is essential for next- generation human-machine interfaces. However, producing tissue-like multilayered geometries and integrating them as e-skin systems requires simplifying and standardizing their manufacture. Here, we present a scalable and cost-effective cure-on-demand strategy for 3D printing nanocomposite silicone rubbers and integrating them into complex soft structures with 1200 % enhanced pressure-strain sensitivity. By utilizing a controlled in-situ mixing of catalyst-cured silicones and shear-driven alignment of carbon nanofibers (CNF), we construct percolated networks with conductivities up to 130 S m(-1) layer-by-layer. We investigate the influence of ink composition, printing parameters, geometrical design, and material density on the mechanical properties, stretchability, sensitivity, and antimicrobial activity of 3D printed piezoresistive sensors and build skin-like interfaces that detect minimal deformations like human physiological signs. This customizable, biocompatible, and robust e-skin holds promise for cost-effective integration in rehabilitation medicine, smart robotics applications, and extended reality (XR) interactive experiences.