Autonomous ultrafast-self-healing hydrogel for application in multiple environments

Self-healing hydrogels have attracted much attention in the fields of biomedicine and wearable electronic devices. However, traditional hydrogels require external stimulation to induce the repair process. Moreover, the relatively weak mechanical properties and long repair time often limit the depth of the hydrogel application. Nevertheless, in this work, we report an ultrafast-self-healing high-strength hydrogel with polyvinyl alcohol (PVA)/diphenylmethane diisocyanate (MDI) as the structural support framework, borax/H3BO3 (BB) solution was used for crosslinking and PVA/glycerin as the dynamic covalent bond. The skeletal structure restricts free PVA segments, and small glycerin molecules form dynamic bonds in a limited area, and thus, a hydrogel with a locally ordered structure is formed. In particular, since numerous hydrogen bonds and dynamic covalent bonds are reversibly formed under the limitation of the skeleton, the hydrogel has a high degree of adaptability and can exhibit self-healing (<5 s, 0.74 MPa) under various conditions. Based on this skeletal structure, the positive feedback function can be realized, so that the hydrogel has ultrafast-self-healing ability, excellent mechanical, anti-freezing performances, and electrical conductivity. The physically connected hydrogel thus prepared can be used in various future application fields, including sensor technology, tissue engineering, and flexible electronics.

Automated summary

The study presents a self-healing hydrogel with ultrafast healing ability and high strength, utilizing a specific structural support framework, crosslinking agent, and dynamic covalent bonds. This hydrogel exhibits high adaptability, quick self-healing, excellent mechanical properties, and electrical conductivity.