Wu Zixuan, Yang Xing, Wu Jin
State Key Laboratory of Optoelectronic Materials and Technologies and the Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China.
ACS Appl Mater Interfaces. 2021 Jan 20;13(2):2128-2144. doi: 10.1021/acsami.0c21841. Epub 2021 Jan 6.
Conductive hydrogels have drawn significant attention in the field of stretchable/wearable sensors due to their intrinsic stretchability, tunable conductivity, biocompatibility, multistimuli sensitivity, and self-healing ability. Recent advancements in hydrogel- and organohydrogel-based sensors, including a novel sensing mechanism, outstanding performance, and broad application scenarios, suggest the great potential of hydrogels for stretchable electronics. However, a systematic summary of hydrogel- and organohydrogel-based sensors in terms of their working principles, unique properties, and promising applications is still lacking. In this spotlight, we present recent advances in hydrogel- and organohydrogel-based stretchable sensors with four main sections: improved stability of hydrogels, fabrication and characterization of organohydrogel, working principles, and performance of different types of sensors. We particularly highlight our recent work on ultrastretchable and high-performance strain, temperature, humidity, and gas sensors based on polyacrylamide/carrageenan double network hydrogel and ethylene glycol/glycerol modified organohydrogels obtained via a facile solvent displacement strategy. The organohydrogels display higher stability (drying and freezing tolerances) and sensing performances than corresponding hydrogels. The sensing mechanisms, key factors influencing the performance, and application prospects of these sensors are revealed. Especially, we find that the hindering effect of polymer networks on the ionic transport is one of the key mechanisms applicable for all four of these kinds of sensors.
由于其固有的拉伸性、可调的导电性、生物相容性、多刺激敏感性和自愈能力，导电水凝胶在可拉伸/可穿戴传感器领域引起了广泛关注。基于水凝胶和有机水凝胶的传感器的最新进展，包括新颖的传感机制、出色的性能和广泛的应用场景，表明水凝胶在可拉伸电子学方面具有巨大潜力。然而，目前仍缺乏对基于水凝胶和有机水凝胶的传感器在工作原理、独特性能和应用前景方面的系统总结。在这篇专题文章中，我们介绍了基于水凝胶和有机水凝胶的可拉伸传感器的最新进展，主要分为四个部分：水凝胶稳定性的提高、有机水凝胶的制备与表征、工作原理以及不同类型传感器的性能。我们特别强调了我们最近在基于聚丙烯酰胺/角叉菜胶双网络水凝胶和通过简便的溶剂置换策略获得的乙二醇/甘油改性有机水凝胶的超拉伸和高性能应变、温度、湿度及气体传感器方面的工作。与相应的水凝胶相比，有机水凝胶表现出更高的稳定性（耐干燥和冷冻）和传感性能。揭示了这些传感器的传感机制、影响性能的关键因素以及应用前景。特别是，我们发现聚合物网络对离子传输的阻碍作用是适用于所有这四种传感器的关键机制之一。
