Biomimetic organohydrogel actuator with high response speed and synergistic fluorescent variation

Current hydrogel-based actuators have achieved rapid development due to their excellent performance such as shape-morphing and color-changing for application in fields such as camouflage, biomimetic soft-robotics and so on. However, it is still challenging to fabricate soft robots with the capability of simultaneous changes in shape and fluorescent color at a fast speed when triggered by one single stimulus. Herein, an anisotropic organohydogel actuator made up of rGO-doped hydrophilic poly(N-isopropylacrylamide) (PNIPAM) network and hydrophobic poly(lauryl methacrylate) (PLMA) network is prepared via a two-step interpenetrating method. Bearing fluorescent monomer N-(4-(1,2,2-triphenylvinyl)phenyl)acrylamide (ATPE) as well as fluorescent ligand 6-acrylamidopicolinic acid (6APA), the PLMA network shows fluorescent changes in color or brightness depending on the presence or absence of Eu3+ ions in response to heat/NIR. In a word, the proposed organohydrogel actuator, which exhibits simultaneous fluorescence color variation and fast morphing in response to one stimulus, provides insights in designing and fabricating novel soft robots.