Strong and Tough Conductive Organo‐Hydrogels via Freeze‐Casting Assisted Solution Substitution
Xinyu Dong, Xiao Guo, Quyang Liu, Yijing Zhao, Haobo Qi, Wei Zhai
Abstract
Abstract High strength, toughness, and conductivity are among the most sought‐after properties of flexible electronics. However, existing engineering materials find it difficult to achieve both excellent mechanical properties and high conductivity. To address this challenge, this study proposes a facile yet versatile strategy for preparing super‐tough conductive organo‐hydrogels via freeze‐casting assisted solution substitution (FASS). This FASS strategy enables the formation of organo‐hydrogels in one step with exquisite hierarchical anisotropic structures coupled with synergistic strengthening and toughening effects across multiple length scales. As an exemplary material, the prepared polyvinyl alcohol (PVA) organo‐hydrogel with solvent content up to 87 wt% exhibits a combination of high strength (6.5 MPa), high stretchability (1710% in strain), ultra‐high toughness (58.9 MJ m −3 ), as well as high ionic conductivity up to 6.5 S m −1 with excellent strain sensitivity. The exceptional combination of mechanical properties and conductivity makes the PVA organo‐hydrogel a promising flexible electronics material. In addition, the FASS strategy can also endow hydrogels with multi‐functions, including thermo‐healability, freezing tolerance and shape recoverability, and can be applied to various hydrogel materials, such as carboxymethyl cellulose, sodium alginate, and chitosan. Hence, this work provides an all‐around solution for preparing advanced strong and tough conductive soft materials for a multitude of applications.