As one of the most important smart materials, fluorescent hydrogel actuators can produce both color and shape changes under external stimuli. In the present work, an effective approach to develop a novel fluorescent hydrogel actuator with pH and thermo dual responsiveness is proposed. Through incorporating pH‐responsive perylene tetracarboxylic acid (PTCA), which is a typical fluorescent moiety with aggregation‐caused quenching (ACQ) effect, into an anisotropic poly(N‐isopropylacrylamide)–polyacrylamide (PNIPAm‐PAAm) structure, the obtained hydrogel exhibits stable thermoresponsive shape deformation and switchable fluorescence performance upon a pH trigger. Therefore, fluorescence‐quenching‐based and actuation‐based information can be revealed when exposed to UV light and immersed into warm water, respectively. Moreover, the thermoresponsive actuating behavior can be applied to further hide the fluorescence‐quenching‐based images. The present work may provide new insights into the design and preparation of novel stimuli‐responsive hydrogel actuators.

中文翻译：

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pH 和热双响应荧光水凝胶执行器

作为最重要的智能材料之一，荧光水凝胶致动器可以在外部刺激下产生颜色和形状的变化。在目前的工作中，提出了一种开发具有 pH 和热双重响应性的新型荧光水凝胶致动器的有效方法。通过将 pH 响应性苝四羧酸 (PTCA)（一种典型的具有聚集引起猝灭（ACQ）效应的荧光部分）结合到各向异性聚（N-异丙基丙烯酰胺）-聚丙烯酰胺（PNIPAm-PAAm）结构，所获得的水凝胶在pH触发下表现出稳定的热响应形状变形和可切换的荧光性能。因此，当暴露在紫外线下和浸入温水中时，可以分别显示基于荧光猝灭和基于驱动的信息。此外，热响应驱动行为可用于进一步隐藏基于荧光猝灭的图像。目前的工作可能为新型刺激响应水凝胶致动器的设计和制备提供新的见解。