Ionic Skin with Biomimetic Dielectric Layer Templated from <i>Calathea Zebrine</i> Leaf

TLDR

Flexible electronic skins that can sense pressure with high sensitivity are highly desired, yet capacitive e‑skins suffer from limited dielectric deformation and costly microfabrication of surface structures. The study reports a low‑cost microstructured ionic gel with uniform cone‑like surface microstructures for high‑performance capacitive e‑skins. The MIG film is fabricated by soft lithography from a Calathea zebrine leaf and sandwiched between flexible electrodes, forming electric double layers whose area expands when the cone‑like microstructures compress. The device achieves a 0.1 Pa detection limit, an ultrahigh sensitivity of 54.31 kPa⁻¹ below 0.5 kPa, and maintains sensitivity above 1 kPa⁻¹ up to 115 kPa, enabling sensitive tactile sensing for human–machine interaction.

Abstract

Abstract Flexible electronic skins (e‐skins) with high sensitivity and broad‐range pressure sensing are highly desired in artificial intelligence, and human–machine interaction. Capacitive‐type e‐skins have a simple configuration, but the change in dimensions of the dielectric layer is often quite limited, although introducing surface microstructures might improve the sensitivity in some extent. Moreover, such surface structures typically require costly microfabrication methods to fabricate. Here, a low‐cost microstructured ionic gel (MIG) with uniform cone‐like surface microstructures for high‐performance capacitive e‐skins is reported. The MIG film is templated from a Calathea zebrine leaf using soft lithography, and sandwiched by two flexible electrodes. The device exhibits a low limit of detection down to 0.1 Pa, a ultrahigh sensitivity of 54.31 kPa −1 in the low pressure regime (&lt;0.5 kPa), and the sensitivity keeps larger than 1 kPa −1 over a broad‐range pressure from 0.1 Pa to 115 kPa. Electric double layers (EDL) form on both the top and bottom interfaces, and the area of EDL of the rough interface increases as the cones are compressed. Such ionic skins with biomimetic gel templated Calathea zebrine leaf allow for sensitive tactile sensing in the applications of human–machine interaction.