Hydrogels that are capable of autonomous healing upon damage have attracted wide attention in recent years. The design and fabrication of hydrogels possessing both excellent self-healing and high strength is highly desired. Herein, we report the facile synthesis of self-healing poly(MAH-β-CD-co-AA) hydrogels (MAH-β-CD = β-cyclodextrin grafted vinyl carboxylic acid groups; AA = acroleic acid) via frontal polymerization (FP) for the first time. When ignited by a soldering iron, frontal polymerization occurred to fabricate poly(MAH-β-CD-co-AA) hydrogels within 10 min. The as-fabricated hydrogels exhibited pH sensitivity and high mechanical strength and could repair themselves autonomously without any external stimuli. In addition, we reinforced poly(MAH-β-CD-co-AA) hydrogel through further cross-linking with N-isopropylacrylamide to form a double network (DN) hydrogel. Benefiting from the excellent self-healing property, a Janus bilayer hydrogel toward temperature-triggered actuator was achieved by simply sticking poly(MAH-β-CD-co-AA) and DN hydrogel together. This hydrogel actuator was very sensitive to thermal stimulus, which showed a rapid response in several seconds. This work might promote the development of diverse functional self-healing hydrogels via a facile and flexible pathway.

中文翻译：

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面向前部聚合的自修复水凝胶及其在温度触发致动器中的应用

近年来，能够自愈而能够自愈的水凝胶引起了广泛的关注。非常需要具有优异的自愈性和高强度的水凝胶的设计和制造。在这里，我们报道了通过额叶聚合（FP）容易地合成自修复的聚（MAH-β-CD- co -AA）水凝胶（MAH-β-CD=β-环糊精接枝的乙烯基羧酸基团； AA =丙烯醛酸） ）。当用烙铁点燃时，发生了正面聚合反应，从而在10分钟内制备了聚（MAH-β-CD- co - AA）水凝胶。所制备的水凝胶表现出pH敏感性和高机械强度，并且可以在没有任何外部刺激的情况下自动修复。另外，我们增强了聚（MAH-β-CD- co-AA）水凝胶通过与N-异丙基丙烯酰胺的进一步交联形成双网络（DN）水凝胶。得益于出色的自我修复性能，通过将聚（MAH-β-CD- co - AA）和DN水凝胶简单地粘合在一起，即可获得Janus双层水凝胶，可用于温度触发型致动器。这种水凝胶致动器对热刺激非常敏感，它在几秒钟内显示出快速响应。这项工作可能会通过便捷和灵活的途径促进多种功能性自愈水凝胶的开发。