A Damage-Perceptive, Self-Healing Electronic Skin with Millimeter Resolution

Abstract

In living tissue, pain provides a localized alert to damage and elicits an adaptive response, including the ability to heal. Mimicking these abilities in soft robotics is a key challenge with implications for durability, repairability, and device functionality. Here, we design a self-healing electronic skin capable of sensing damage inflicted by scalpels and needles at ~1 millimeter resolution over ~10 cm2. Our approach integrates a set of functional self-healing composites, scalable prototyping processes, and multilayer circuit designs to precisely sense the position of damage in multiple spatial dimensions and functionally repairing from ~1–100 cycles of damage, depending upon the multilayer structure and mechanism of damage. In our design, unidirectional voltage gradients with a linear dependence on position are applied across resistive ‘drive’ layers. Analog ‘sense’ layers detect lateral position and depth of metal objects by sensing the voltage upon formation of an electrical contact with the drive layer(s) during damage within the active sensing area. These functional electronic layers can be arranged into various stacked configurations, separated by self-healing insulating layers, to achieve a multitude of sensing modalities including one-, two-, and three-dimensional sensing of damage position over time. Proof-of-concept experiments validate these sensing capabilities through comparison to synchronized measurements obtained with an underlying precision 6-axis force sensor. The ability to precisely detect punctures and incisions in soft, self-healable materials at millimeter resolution may have implications in the development of reusable, multisensory surgical simulation technology for training medical personnel and evaluating efficacy of surgical robotic systems.

Keywords: self-healing devices, damage-sensing, functional composites, soft robotics, electronic skins