Mussel-Inspired Highly Stretchable, Tough Nanocomposite Hydrogel with Self-Healable and Near-Infrared Actuated Performance

Based on the adhesive mechanism of mussels, we present a facile strategy to prepare nanocomposite polydopamine-poly(N-acryloyl glycinamide)-graphene oxide (PDA-PNAGA-GO) hydrogels with lots of catechol groups in the matrix of hydrogel. The microfibril structure formed by PDA chains enables the hydrogels high stretchability (∼1500%) and toughness (6990 J/m²); the multiple hydrogen bonding interactions and π-πinteractions among the PNAGA network and PDA chains also enable a hydrogel perfect self-healing performance. Moreover, GO in the hydrogel can absorb the near-infrared irradiation, resulting in the temperature difference between the surface and bottom area and then a bending deformation (with 40% of actuation degree) of the hydrogel. Besides, the GO can also make the hydrogels electrically conductive, and the self-healing efficiency (∼87% for the first healing) could also be calculated according to the retention rate of conductivity of hydrogel after being healed at 90 °C. The unique properties will enable the PDA-PNAGA-GO hydrogels to be widely used in the field of tissue engineering and soft actuators.