Ultrastretchable hydrogels with strong damping effects

Hydrogels can be stretched to several tens or even hundreds of times their original lengths, making them suitable for various applications. They have shown great potential for use in sensors and wearable devices. Although many attempts have been made to develop highly stretchable hydrogels, combining high stretchability and excellent damping remains a challenge. This study reports a method that significantly improved the stretchability and damping properties of hydrogels. The innovation is the replacement of traditional short-chain crosslinkers, such as N,N-methylenebis(acrylamide) (MBA), with long-chain crosslinkers. With increasing chain lengths, the spaces in the networks became larger, which reduced the interactions between the molecular chains in the network. As a result, the molecular chains of the network could slide when stretched, which greatly increased the mechanical elongation and enabled damping by the hydrogel (up to 85%). The maximum elongation reached 21800%, with a toughness of 11.32 MJ m⁻³. To the best of our knowledge, this elongation is superior to those in all previous reports. Our results provide a new approach for the development of highly stretchable and damping hydrogels.