Hierarchical Multi‐Material Architectures With Gradient Design for Dynamic‐Range Flexible Tactile Sensing

ABSTRACT Flexible pressure sensors that can simultaneously provide mechanical compliance, a broad detection range, and robust operation under complex loading conditions are highly desired for next‐generation electronic skin (e‐skin) and wearable systems. Herein, we report a hierarchical multi‐material by‐layer sensor (HMBS) based on triply periodic minimal surface (TPMS) architectures, fabricated through an additive manufacturing‐assisted template‐based casting strategy and functionalized with a hierarchical electrically conductive coating. Gyroid and diamond TPMS lattices are combined in a multi‐stacked configuration, with a soft PDMS gyroid layer on top of a stiffer PDMS diamond layer, to introduce a vertical stiffness gradient and graded deformation under compression. The sacrificial ABS moulds, 3D printed from inverse TPMS geometries, allow accurate control of lattice topology while in situ polypyrrole (PPy) polymerization followed by MWCNT dip‐coating forms a conformal 3D conductive coating network throughout the scaffold. The HMBS shows a continuous, non‐saturating piezoresistive response from 3.75 to 375 kPa and remains stable over 4000 loading–unloading cycles across relevant frequencies. We further demonstrate reliable sensing of non‐uniform, localized, and dynamic/vibration‐induced loads, representative of bio‐signal‐like stimuli. These results showcase a hierarchical TPMS‐based platform for architected, multi‐material tactile sensors and provide a scalable design paradigm for bio‐integrated wearables, and human–machine interface platforms.