Ultra-stretchable, self-recoverable, notch-insensitive, self-healable and adhesive hydrogel enabled by synergetic hydrogen and dipole-dipole crosslinking.

Abstract

Hydrogels are promising materials for wearable electronics, artificial skins and biomedical engineering, but their limited stretchability, self-recovery and crack resistance restrict their performance in demanding applications. Despite efforts to enhance these properties using micelle cross-links, nanofillers and dynamic interactions, it remains a challenge to fabricate hydrogels that combine high stretchability, self-healing and strong adhesion. Herein, we report a novel hydrogel synthesized via the copolymerization of acrylamide (AM), maleic acid (MA) and acrylonitrile (AN), designed to address these limitations. The resulting hydrogel forms a dual physical crosslinking network enabled by dynamic hydrogen bonds and dipole-dipole interactions. This hierarchical structure allows polymer chains to undergo progressive deformation, leading to ultrahigh stretchability exceeding 9000% and excellent fatigue resistance under cyclic strains of up to 3000%. Furthermore, the hydrogel exhibits outstanding notch-insensitivity (fracture energy: >10 kJ m^-2), notable adhesive properties and superior self-healing capabilities. The incorporation of LiCl imparts conductivity to the hydrogel, making it suitable for wearable strain sensors that can accurately monitor human motion. These results demonstrate the successful development of an ultra-stretchable, self-recoverable, notch-insensitive, self-healable and adhesive hydrogel with significant potential for advanced applications in wearable electronics and healthcare monitoring devices. This work represents a significant step forward in the design of multifunctional hydrogels, offering new pathways for the development of next-generation soft materials with enhanced mechanical and functional properties.