Tough, Self-Healing, and Conductive Elastomer ─Ionic PEGgel
Journal
ACS applied materials & interfaces
Journal Volume
14
Journal Issue
44
Pages
50152
Date Issued
2022-10-28
Author(s)
Wang, Zhenwu
Lai, Yu-Cheng
Chiang, Ya-Tang
Scheiger, Johannes Martin
Li, Shuai
Dong, Zheqin
Cai, Qianyu
Liu, Sida
Hsu, Shan-Hui
Levkin, Pavel A
Abstract
Ionically conductive elastomers are necessary for realizing human-machine interfaces, bioelectronic applications, or durable wearable sensors. Current design strategies, however, often suffer from solvent leakage and evaporation, or from poor mechanical properties. Here, we report a strategy to fabricate ionic elastomers (IHPs) demonstrating high conductivity (0.04 S m-1), excellent electrochemical stability (>60,000 cycles), ultra-stretchability (up to 1400%), high toughness (7.16 MJ m-3), and fast self-healing properties, enabling the restoration of ionic conductivity within seconds, as well as no solvent leakage. The ionic elastomer is composed of in situ formed physically cross-linked poly(2-hydroxyethyl methacrylate) networks and poly(ethylene glycol) (PEG). The long molecular chains of PEG serve as a solvent for dissolving electrolytes, improve its long-term stability, reduce solvent leakage, and ensure the outstanding mechanical properties of the IHP. Surprisingly, the incorporation of ions into PEG simultaneously enhances the strength and toughness of the elastomer. The strengthening and toughening mechanisms were further revealed by molecular simulation. We demonstrate an application of the IHPs as (a) flexible sensors for strain or temperature sensing, (b) skin electrodes for recording electrocardiograms, and (c) a tough and sensing material for pneumatic artificial muscles. The proposed strategy is simple and easily scalable and can further inspire the design of novel ionic elastomers for ionotronics applications.
Subjects
flexible electronics; ionic elastomers; ionotronics; self-healing materials; strain sensors
Publisher
AMER CHEMICAL SOC
Type
journal article