Bio-inspired adhesive and self-healing hydrogels as flexible strain sensors for monitoring human activities.

Nowadays, hydrogels have been intensively explored due to their promising potential application in bioelectronics. However, the lack of self-healing performance limits the lifespan and stability of materials. Here, a stretchable, self-healing and conductive hydrogel is prepared via physical crosslinking including hydrogen bonding, hydrophobic association and complexation effect, endowing the hydrogels with stretchability of 1150%, tensile strength of 112 kPa, flexibility and puncture resistance. Besides, the hydrogels possess extraordinary conductive property with a conductivity of 0.0720 S cm and exhibit stable changes of resistance signals with a gauge factor of 2.506. Meanwhile, the hydrogels also exhibit adhesive performance due to the presence of catechol groups, and the maximum peeling adhesive strength could reach 23 N m. It is envisioned that the highly stretchable, self-healable, adhesive and conductive hydrogels would widen the application as the flexible strain sensors for soft robots, artificial limb, movement-monitoring equipment.