Giant Tunneling Piezoresistance of Composite Elastomers with Interlocked Microdome Arrays for Ultrasensitive and Multimodal Electronic Skins

TLDR

Flexible electronic skins demand high sensitivity and multimodal sensing, yet piezoresistive composite elastomers suffer from low sensitivity, slow response, and temperature‑driven signal drift. The study introduces a flexible electronic skin design that incorporates interlocked microdome arrays in composite elastomer films to achieve giant tunneling piezoresistance. The interlocked microdome arrays amplify contact area changes under load, enabling extreme resistance switching with an ROFF/RON ratio of about 10⁵. The resulting sensors exhibit ultra‑high pressure sensitivity (−15.1 kPa⁻¹, ≈0.2 Pa minimum detection), rapid response/relaxation (~0.04 s), minimal temperature dependence, and can sensitively monitor human breathing flows and voice vibrations for wearable health monitoring.

Abstract

The development of flexible electronic skins with high sensitivities and multimodal sensing capabilities is of great interest for applications ranging from human healthcare monitoring to robotic skins to prosthetic limbs. Although piezoresistive composite elastomers have shown great promise in this area of research, typically poor sensitivities and low response times, as well as signal drifts with temperature, have prevented further development of these materials in electronic skin applications. Here, we introduce and demonstrate a design of flexible electronic skins based on composite elastomer films that contain interlocked microdome arrays and display giant tunneling piezoresistance. Our design substantially increases the change in contact area upon loading and enables an extreme resistance-switching behavior (ROFF/RON of ∼10(5)). This translates into high sensitivity to pressure (-15.1 kPa(-1), ∼0.2 Pa minimum detection) and rapid response/relaxation times (∼0.04 s), with a minimal dependence on temperature variation. We show that our sensors can sensitively monitor human breathing flows and voice vibrations, highlighting their potential use in wearable human-health monitoring systems.