Zhang Yingying, Fan Guanglin, Jiang Jinqiang, Liu Zhaotie, Liu Zhongwen, Li Guo
Key Laboratory of Syngas Conversion of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi Province 710062, China.
ACS Appl Mater Interfaces. 2022 Jun 29;14(25):29188-29196. doi: 10.1021/acsami.2c04679. Epub 2022 Jun 16.
Hydrogel actuators have gained considerable interest and experienced significant advancements in recent years. However, the programming of their actuating behaviors is still challenging. Herein, we report the development and regulation of gradient structures of hydrogels for programmable thermally responsive actuating behaviors. The hydrogel actuators are developed by controlling the photoreduction of Fe ions coordinated with carboxylate groups from the substrates and their limited diffusion into the precursor solutions to act as both initiators and crosslinkers. The developed hydrogels show well-defined external geometries and controllable thicknesses under spatiotemporal control of ultraviolet irradiation. The shapes and the actuation amplitudes of the hydrogel actuators can be independently regulated by controlling the formation and photodissociation of Fe-carboxylate coordination in the formed gradient networks. Some interesting applications such as the lifting of an object with a specific shape and directional walking are realized. The proposed method can be extended to other hydrogel actuators with different compositions and stimuli-responsive behaviors.
近年来，水凝胶致动器引起了广泛关注并取得了显著进展。然而，对其致动行为进行编程仍然具有挑战性。在此，我们报告了用于可编程热响应致动行为的水凝胶梯度结构的开发与调控。通过控制与底物中羧基配位的铁离子的光还原以及它们向前驱体溶液中的有限扩散，使其既作为引发剂又作为交联剂，从而开发出水凝胶致动器。在紫外线照射的时空控制下，所开发的水凝胶呈现出明确的外部几何形状和可控的厚度。通过控制所形成的梯度网络中铁 - 羧基配位的形成和光解离，可以独立调节水凝胶致动器的形状和致动幅度。实现了一些有趣的应用，如提起特定形状的物体和定向行走。所提出的方法可以扩展到具有不同组成和刺激响应行为的其他水凝胶致动器。
