A Snakeskin‐Inspired, Soft‐Hinge Kirigami Metamaterial for Self‐Adaptive Conformal Electronic Armor

Abstract

A majority of soft‐body creatures evolve armor or shells to protect themselves. Similar protection demand is for flexible electronics working in complex environments. Existing works mainly focus on improving the sensing capabilities such as electronic skin (E‐skin). Inspired by snakeskin, a novel electronic armor (E‐armor) is proposed, which not only possesses mechanical flexibility and electronic functions similar to E‐skin, but is also able to protect itself and the underlying soft body from external physical damage. The geometry of the kirigami mechanical metamaterial (Kiri‐MM) ensures auxetic stretchability and meanwhile large areal coverage for sufficient protection. Moreover, to suppress the inherent but undesired out‐of‐plane buckling of conventional Kiri‐MMs for conformal applications, soft hinges are used to form a distinct soft (hinges)‐rigid (tiles) configuration. Analytical, computational, and experimental studies of the mechanical behaviors of the soft‐hinge Kiri‐MM E‐armor demonstrate the merits of this design, i.e., stretchability, conformability, and protectability, as applied to flexible electronics. Deploying a conductive soft material at the hinges enables facile wiring strategies for large‐scale circuit arrays. Functional E‐armor systems for controllable display and sensing purposes provide simple examples of a wide spectrum of applications of this concept.

Technology Roadmap for Flexible Sensors

“…Discrete dispersion of rigid components in a soft polymer matrix has shown effectiveness in preventing damage by puncture or cut to the active components . Stretchable armors composed of hard scales connected by soft elastomers enhance resistance to puncture, scratch, and cut, when used as an additional protective layer for flexible devices or functionalized as standalone flexible sensors . Such artificial armors with nature-inspired designs may find wider application in wearable sensors and electronic skin.…”

Advances in flexible sensors for intelligent perception system enhanced by artificial intelligence

“…(E) Schematic diagram of the soft hinge formed by conductive elastomer, circuits, and PI tile. (F) An E‐armor tube with a duck egg mimicking the swallowing process of a snake 329 . Copyright 2022, Wiley‐VCH.…”

Auxetic Kirigami Metamaterials upon Large Stretching

“…They can realize desirable properties, ranging from high stretchability, − multi-stability, − optical metasurface, − unusual thermo-mechanic properties, − high indentation resistance, − to programmable Poisson’s ratios, − through rational design of periodic slender cuts on thin sheets. Among various KMs, auxetic KMs with negative Poisson’s ratios have attracted great interest because of their counterintuitive tension-expansion properties, which enable special functionals like tunable deformation modes. , In particular, auxetic KMs have shown great potential for innovative applications in the fields of soft robotics, ,,− acoustic materials, photoelectric materials, , flexible electronics, − etc.…”