Artificially innervated self-healing foams as synthetic piezo-impedance sensor skins

TLDR

Human skin is a self‑healing mechanosensory system that efficiently detects mechanical contact forces via three‑dimensional innervations. The study proposes a biomimetic, artificially innervated foam embedding 3‑D electrodes in a low‑modulus self‑healing material. The foam is produced via a one‑step self‑foaming process and, by tuning conductive metal particle concentration near percolation, functions as a piezo‑impedance sensor in both piezoresistive and piezocapacitive modes without encapsulation. The sensor detects contact force direction and human proximity, self‑heals autonomously restoring function after damage, recovers from mechanical bifurcations with gentle heating, and is anticipated to be useful for damage‑robust human‑machine interfaces.

Abstract

Abstract Human skin is a self-healing mechanosensory system that detects various mechanical contact forces efficiently through three-dimensional innervations. Here, we propose a biomimetic artificially innervated foam by embedding three-dimensional electrodes within a new low-modulus self-healing foam material. The foam material is synthesized from a one-step self-foaming process. By tuning the concentration of conductive metal particles in the foam at near-percolation, we demonstrate that it can operate as a piezo-impedance sensor in both piezoresistive and piezocapacitive sensing modes without the need for an encapsulation layer. The sensor is sensitive to an object’s contact force directions as well as to human proximity. Moreover, the foam material self-heals autonomously with immediate function restoration despite mechanical damage. It further recovers from mechanical bifurcations with gentle heating (70 °C). We anticipate that this material will be useful as damage robust human-machine interfaces.