Highly Stretchable, Elastic, and Ionic Conductive Hydrogel for Artificial Soft Electronics

TLDR

Soft electronics demand high conductivity, strength, and stretchability, yet materials that balance these properties are scarce. The study introduces a simple fabrication route to generate ion‑rich porous hydrogels that combine high conductivity with robust, stretchable mechanics. The hydrogel is made by physically cross‑linking a tough polyvinyl alcohol matrix, embedding hydroxypropyl cellulose fibers, and soaking the composite in salt to create ion‑rich pores. The resulting material delivers 1.3 MPa stress, 975 % strain, and 3.4 S m⁻¹ ionic conductivity at 1 MHz, and functions as a stable, tunable artificial nerve in a 3D‑printed robotic hand, underscoring its promise for flexible electronics.

Abstract

Abstract High conductivity, large mechanical strength, and elongation are important parameters for soft electronic applications. However, it is difficult to find a material with balanced electronic and mechanical performance. Here, a simple method is developed to introduce ion‐rich pores into strong hydrogel matrix and fabricate a novel ionic conductive hydrogel with a high level of electronic and mechanical properties. The proposed ionic conductive hydrogel is achieved by physically cross‐linking the tough biocompatible polyvinyl alcohol (PVA) gel as the matrix and embedding hydroxypropyl cellulose (HPC) biopolymer fibers inside matrix followed by salt solution soaking. The wrinkle and dense structure induced by salting in PVA matrix provides large stress (1.3 MPa) and strain (975%). The well‐distributed porous structure as well as ion migration–facilitated ion‐rich environment generated by embedded HPC fibers dramatically enhances ionic conductivity (up to 3.4 S m −1 , at f = 1 MHz). The conductive hybrid hydrogel can work as an artificial nerve in a 3D printed robotic hand, allowing passing of stable and tunable electrical signals and full recovery under robotic hand finger movements. This natural rubber‐like ionic conductive hydrogel has a promising application in artificial flexible electronics.