State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
ACS Appl Mater Interfaces. 2021 Jan 13;13(1):1353-1366. doi: 10.1021/acsami.0c16719. Epub 2020 Dec 22.
Stimulus-responsive hydrogels, such as conductive hydrogels and thermoresponsive hydrogels, have been explored extensively and are considered promising candidates for smart materials such as wearable devices and artificial muscles. However, most of the existing studies on stimulus-responsive hydrogels have mainly focused on their single stimulus-responsive property and have not explored multistimulus-responsive or multifunction properties. Although some works involved multifunctionality, the prepared hydrogels were incompatible. In this work, a multistimulus-responsive and multifunctional hydrogel system (carboxymethyl cellulose/poly acrylic-acrylamide) with good elasticity, superior flexibility, and stable conductivity was prepared. The prepared hydrogel not only showed excellent human motion detection and physiological signal response but also possessed the ability to respond to environmental temperature changes. By integrating a conductive hydrogel with a thermoresponsive poly(-isopropylacrylamide) (PNIPAM) hydrogel to form a bilayer hydrogel, the prepared bilayer also functioned as two kinds of actuators owing to the different degrees of swelling and shrinking under different thermal stimuli. Furthermore, the different thermochromic properties of each layer in the bilayer hydrogel endowed the hydrogel with a thermoresponsive "smart" feature, the ability to display and conceal information. Therefore, the prepared hydrogel system has excellent prospects as a smart material in different applications, such as ionic skin, smart info-window, and soft robotics.
刺激响应水凝胶，如导电水凝胶和温敏水凝胶，已经得到了广泛的研究，被认为是智能材料（如可穿戴设备和人工肌肉）的有前途的候选材料。然而，大多数现有的刺激响应水凝胶研究主要集中在其单一的刺激响应特性上，而没有探索多刺激响应或多功能特性。尽管一些工作涉及多功能性，但所制备的水凝胶是不相容的。在这项工作中，制备了一种具有良好弹性、优异柔韧性和稳定导电性的多刺激响应多功能水凝胶体系（羧甲基纤维素/聚丙烯酸-丙烯酰胺）。所制备的水凝胶不仅表现出优异的人体运动检测和生理信号响应能力，而且还具有响应环境温度变化的能力。通过将导电水凝胶与温敏聚（异丙基丙烯酰胺）（PNIPAM）水凝胶集成形成双层水凝胶，由于在不同热刺激下的不同程度的溶胀和收缩，所制备的双层水凝胶还充当了两种致动器。此外，双层水凝胶中每层的不同热致变色特性赋予水凝胶具有热敏“智能”特性，能够显示和隐藏信息。因此，所制备的水凝胶系统作为智能材料在不同应用中具有广阔的前景，如离子皮肤、智能信息窗口和软机器人。
