writer：Wenjie Zeng, Chenguang Jiang, Defeng Wu*
keywords：polysaccharides; bilayer hydrogels; heterogeneity; actuator; sensors.
source：期刊
specific source：ACS Applied Materials & Interfaces
Issue time：2023年

ACS Applied Materials & Interfaces, 2023, 15(12), 16097–16108. 

Bilayer hydrogel-based actuator has attracted much interest because inhomogeneous structure is easily constructed in hydrogels. We used three kinds of polysaccharides, including anionic carboxymethyl cellulose (CMC), cationic chitosan (CS), and amphoteric carboxymethyl chitosan (CMCS), as both structure-constructing units and actuation-controlling units in this work to fabricate physically cross-linked poly(vinyl alcohol) bilayer hydrogels. The spatial heterogeneity was tuned by changing types and concentrations of polysaccharides in different layers, in this way to regulate pH- and humidity-driven actions of bilayer hydrogels. Based on the distortion of ionic channel during the humidity-motivated deformation of bilayer hydrogels, a two-in-one flexible device integrating humidity-driven actuator and humidity-responsive sensor was then developed, which could detect the alterations of environmental humidity in real time. Moreover, good tensile toughness and interfacial bonding, as well as strain-resistance effect endowed the bilayer hydrogels with the capability of identifying human motion as strain sensor, unlocking more application scenarios. This work provides an overall insight into heterogeneity regulation of bilayer hydrogels by using polysaccharides as stimulus-responsive units, and also proposes an interesting strategy of manufacturing hydrogel-based flexible devices with both actuating and sensing capabilities.

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https://pubs.acs.org/doi/full/10.1021/acsami.3c01244

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http://www.polymer.cn/sci/kjxw21250.html