Tough Ion-Conductive Hydrogel with Anti-Dehydration as a Stretchable Strain Sensor for Gesture Recognition

摘要

Stretchable hydrogel-based strain sensors have attractedconsiderableinterest for their potential applications in human motion detection,physiological monitoring, and electronic skin. Yet, the durabilityof hydrogel sensors is seriously hindered due to inevitable waterevaporation and weak mechanical properties. Herein, we report modifiedpolyampholyte (PA) hydrogels that show anti-dehydration and ion conductivityvia a simple metal-ion solution soaking and drying-out strategy. Inthis strategy, an as-prepared PA hydrogel (with ionic bonds) is dialyzedin FeCl3 solutions (Step-I) and annealed at 65 & DEG;Cfor (Step-II) successively to reconstruct its network with numeroussynergistic ionic and metal-ligand bonds. The resulting hydrogelsdemonstrate superior mechanical properties, ultralong anti-dehydrationlife span (>30 days), and high ion conductivity (& AP;15 S m(-1)). To understand the reinforcement mechanisms, weevaluate the viscoelastic and elastic contributions to the mechanicalproperties of the hydrogels via a viscoelastic model. This gel canbe further engineered to a stretchable strain sensor to recognizehand gestures with a well-trained machine learning algorithm. Theproposed strategy is straightforward and effective for achieving anti-dehydrationand highly ion-conductive tough hydrogels.

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