Natural Plant Materials as Dielectric Layer for Highly Sensitive Flexible Electronic Skin

TLDR

Nature has long provided useful materials for human use. The authors propose a green, cost‑effective, scalable strategy to fabricate flexible e‑skins using ubiquitous plant foam‑like structures. Plant materials such as flowers and leaves are directly used as dielectric layers in a flexible capacitive e‑skin, where the 3D cell‑wall network acts as a compressible metamaterial that collapses elastically under pressure, enabling sensitive pressure response. The e‑skin operates over 0.6 Pa to 115 kPa with a maximum sensitivity of 1.54 kPa⁻¹, remains stable after 5,000 cycles, and has been applied to touch sensing, motion monitoring, gas flow detection, and pressure mapping.

Abstract

Nature has long offered human beings with useful materials. Herein, plant materials including flowers and leaves have been directly used as the dielectric material in flexible capacitive electronic skin (e-skin), which simply consists of a dried flower petal or leaf sandwiched by two flexible electrodes. The plant material is a 3D cell wall network which plays like a compressible metamaterial that elastically collapses upon pressing plus some specific surface structures, and thus the device can sensitively respond to pressure. The device works over a broad-pressure range from 0.6 Pa to 115 kPa with a maximum sensitivity of 1.54 kPa-1 , and shows high stability over 5000 cyclic pressings or bends. The natural-material-based e-skin has been applied in touch sensing, motion monitoring, gas flow detection, and the spatial distribution of pressure. As the foam-like structure is ubiquitous in plants, a general strategy for a green, cost-effective, and scalable approach to make flexible e-skins is offered here.