Sea-Cucumber Inspired Soft-Stiff Transition Hydrogels with Integrated Shape Morphing and Energy-Dissipating Performances

Abstract Energy-dissipating materials have the ability to protect fragile items from impact-induced damage; however, currently investigated energy-dissipating materials are generally unable to adapt to items with different shapes because they lack shape programmability. Herein, a highly damping polymer hydrogel with thermoresponsive shape programmability is introduced, which was prepared through the copolymerization of acrylic acid and adamantan-1-yl acrylate, followed by coordination with calcium acetate. The hydrogel exhibits excellent shape memory performance due to the Ca2+-assisted hydrophobic phase separation and can be programmed into various temporary shapes. Moreover, the hydrogel possesses a high damping capacity owing to the hydrophobic association of the adamantyl moieties and the dynamic coordination between Ca2+ and the hydrogel network. By combining excellent shape memory capability with high damping performance, the hydrogel demonstrates great potential for applications in protecting items with various shapes.