Tough, adhesive, self-healing, fully physical crosslinked κ-CG-K+/pHEAA double-network ionic conductive hydrogels for wearable sensors
Tough, adhesive, self-healing, fully physical crosslinked κ-CG-K+/pHEAA double-network ionic conductive hydrogels for wearable sensors
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DOI：
10.1016/j.polymer.2021.124321
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发表时间：
2021-11
期刊：
影响因子：
4.6
通讯作者：
Jianxiong Xu;Ziyu Guo;Yin Chen;Yuecong Luo;Shaowen Xie;Yutong Zhang;Haihu Tan;Lijian Xu;Jie Zheng
中科院分区：
文献类型：
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作者：
Jianxiong Xu;Ziyu Guo;Yin Chen;Yuecong Luo;Shaowen Xie;Yutong Zhang;Haihu Tan;Lijian Xu;Jie Zheng
事实证明，开发具有高机械强度、快速自修复、强表面附着力和应变敏感性等综合优点的多功能导电水凝胶对于不同的应用来说是一项要求很高但极具挑战性的任务。在此，我们使用简便的加热-冷却-光聚合过程设计、合成并表征了完全物理交联的κ-卡拉胶/聚(N-羟乙基丙烯酰胺)双网络(DN)水凝胶(κ-CG-K+/pHEAA DN凝胶)。由于互穿的 DN 结构和可逆的混合离子氢键交联网络，所得的 κ-CG-K+/pHEAA 凝胶表现出高机械性能（拉伸强度为 2.02 MPa、拉伸应变为 1550%、弹性模量为 0.91 MPa）和自修复性能。除了大量的高机械性能之外，κ-CG-K+/pHEAA 凝胶还在不同的未经处理的硬质基材（即钛、铝、陶瓷和玻璃）上表现出约 773 J/m2 的高表面粘附力，这源于 pHEAA 聚合物链中丰富的官能团（羟基和酰胺）。此外，DN 凝胶还具有电导率、应变灵敏度（应变系数 (GF) = 2.48）以及由于 K+ 和拉伸相关的电阻变化的存在而产生的传感稳定性。 κ-CG-K+/pHEAA 凝胶中这种高机械、粘合和导电特性的独特组合使我们能够将它们进一步制造成基于凝胶的应变传感器，具有高且快速的灵敏度，用于检测细微应变引起的人体运动。这项工作的设计理念和水凝胶系统为广泛的人机界面应用提供了一个新的角度。
The development of multiple-functional conductive hydrogels with combined merits of high mechanical strength, fast self-healing, strong surface adhesion, and strain sensibility has proved to be a highly demanded, but extremely challenging task for different applications. Herein, we designed, synthesized, and characterized fully physically crosslinked double-network (DN) hydrogels of κ-carrageenan/poly(N-hydroxyethyl acrylamide) (κ-CG-K+/pHEAA DN gels) using a facile heating-cooling-photopolymerization process. The resultant κ-CG-K+/pHEAA gels exhibited highly mechanical (tensile strength of 2.02 MPa, tensile strain of 1550%, and elastic modulus of 0.91 MPa) and self-healing properties owing to the interpenetrating DN structures and reversible hybrid ionic-hydrogen bond cross-linking networks. In parallel to high mechanical properties in bulk, κ-CG-K+/pHEAA gels also demonstrated their high surface adhesion of ∼773 J/m2on different untreated hard substrates (i.e., titanium, aluminum, ceramic, and glass), which stemmed from the rich-functional groups (hydroxyl and amide) in pHEAA polymer chains. Moreover, the DN gels also presented conductivity, strain sensitivity with gauge factor (GF) = 2.48, and sensing stability due to the presence of K+and stretching-dependent resistance variations. Such a unique combination of high mechanical, adhesive, and conductive properties in κ-CG-K+/pHEAA gels allows us to further fabricate them into gel-based strain sensors with high and rapid sensitivity for detecting subtle strain-induced human motions. The design concept and hydrogel system from this work provide a new angle for broad human-machine interface applications.