Tunable Swelling Behaviors and Transparency of Stimuli-responsive Supramolecular Hydrogels for Multi-actuation

Smart hydrogels are promising candidates for use in actuation and sensing due to their stimuli-responsive shape morphing and their easy integration with other functional materials. However, the development of multifunctional integration of stimuli-responsive hydrogels for various actuations has not been well unveiled. In this work, we synthesize a novel 3D printable multi-stimuli-responsive poly(N-isopropylacrylamide-co-acrylamide-g-ureidopyrimidinone) (PNAU) supramolecular hydrogel. The swelling behavior, mechanical strength and transparency of PNAU hydrogels can be adjusted by external temperature and solvent micro-environment owing to the molecular design of these supramolecular hydrogels, thus leading to the shape morphing and transparency camouflage. Moreover, the rheological property is studied to optimize the 3D printability of PNAU hydrogels thus the demonstration for multi-actuation with complicated structures is prepared and tested.