Hyperelastic hydrogel stretches 10k percent, bears 50 kg and self-heals

Supplementary Movie 1. The fabrication process of AETC-25 hydrogels. Supplementary Movie 2. AETC-25 hydrogels fully recovered from a strain of 1500% to an initial clamping length of 1 cm within 1 s. Supplementary Movie 3. A cylindrical AETC-25 hydrogel with an initial diameter of 1 cm and a height of 0.3 cm produced large deformation withstanding the weight of 4 tons and fast recovered without any breakage or extrusion of water. Supplementary Movie 4. A cylindrical AETC-25 hydrogel with an initial diameter of 2 cm and a height of 0.3 cm was stretched to an areal strain of 10,000% and fast recovered almost without any residual strain. Supplementary Movie 5. The cuboid pneumatic device made of AETC-25 hydrogels with a cavity of ml (15 mm × 9 mm × 4 mm) was inflated with 550 ml of air (almost 100,000% change in volume), and fast recovered to its initial state within seconds after deflated. Supplementary Movie 6. The cuboid pneumatic device made of Ecoflex 00-30 with a cavity of ml (15 mm × 9 mm × 4 mm) was inflated with 100 ml of air, and could not recover to its initial state after deflated. Supplementary Movie 7. The cuboid pneumatic device made of AETC-25 hydrogels with a cavity of mL (15 mm × 9 mm × 4 mm) was inflated with 50 ml of air. We pierced the inflated pneumatic device at the bottom using the tip of a needle, and the inflated device still kept seal. Supplementary Movie 8. The cuboid pneumatic device made of AETC-25 hydrogels with a cavity of ml (15 mm × 9 mm × 4 mm) was inflated with 50 ml of air. Then we pierced the pneumatic device at the top thinnest area. The hydrogel balloon shrunk to original volume, but after healing for seconds, the cuboid pneumatic device was reinflated without any leakage. Supplementary Movie 9. The cuboid pneumatic device made of AETC-25 hydrogels with a cavity of ml (15 mm × 9 mm × 4 mm) was inflated with 100 ml of air. The device resisted the continuous and violent crashing of the weight (0.5 kg), the bottom of which was coated with silicone grease. Supplementary Movie 10. The AETC-25 hydrogel pneumatic device with a cavity of 27 ml (30 mm × 30 mm × 30 mm) expanded to about 100 times its original size. A PMMA sheet with a thickness of 3 mm coated with silicone grease was placed on the top of the hydrogel balloon. The hydrogel balloon could bear the human weight of 50 kg and instantly bounce back upon removing the weight. Supplementary Movie 11. Grippers made of AETC-25 hydrogels could even remain hyperelastic for half a year, showing long-term service life (RT = 25°C, RH = 40%). Editor’s summary Hydrogels are typically composed of cross-linked networks of polymers that are highly swollen with water. Depending on the specific architecture, they may be able to undergo a large degree of stretching, although usually only in one direction. Chen et al. developed a polyelectrolyte hydrogel that will form a “pearl necklace” structure in the relaxed state. The pearl regions, which form between cross-links, contain a reservoir of chain segments that can uncoil when the polymer is stretched. This structure allows the hydrogels to be reversibly biaxially stretched to a large areal strain and to heal from mechanical damage. —Marc S. Lavine Abstract Hyperelastic materials exhibit a nonlinear elastic response to large strains, whereas hydrogels typically possess a low elastic range due to the nonuniform cross-linking and limited chain segments among cross-links. We developed a hyperelastic hydrogel that possesses a broader elastic range by introducing a reversible pearl-necklace structure, in which beads are connected by strings. The subnanometric beads can efficiently unfold and refold under cyclic mechanical strains; thus, the hydrogel can rapidly recover after being stretched to an areal strain of more than 10,000%. Additionally, the hydrogel can quickly heal from minor mechanical damages such as needle punctures and cuts. These advancements make our ionic hydrogels ideal for multifunctional pneumatic gripper materials; they simultaneously offer an ultralarge gripping range, self-sensing capabilities, and fast healing abilities. LILI CHEN, ZHEKAI JIN, WENWEN FENG, LIN SUN, HAO XU, AND CHAO WANG. SCIENCE. 28 Mar 2024. Vol 383, Issue 6690, pp. 1455-1461 DOI: