Self‐healing, adhesive, photothermal responsive, stretchable, and strain‐sensitive supramolecular nanocomposite hydrogels based on host–guest interactions.

The development of multifunctional supramolecular nanocomposite hydrogels remains challenging. Here, the dynamic host–guest interactions involving the host molecule CB[8] and guest units were utilized to prepare Fe3O4 hybrid supramolecular nanocomposite hydrogels. The results showed that the hydrogels obtained possessed a porous structure. The CB[8]‐modified Fe3O4 (Fe3O4@CB[8]) nanoparticles served as cross‐linkers in forming the network of hydrogels. By adjusting the Fe3O4@CB[8] content, the mechanical properties of the hydrogels could be controlled. The tensile stress was measured at 160 kPa with a fracture strain of 1380%, while the compression stress was 230 kPa at 70% compression strain. The self‐healing efficiency of the hydrogels at room temperature reached 95% after 24 h. The as‐obtained hydrogels show strain sensitivity and have the potential for applications in detecting elbow and finger movements. Our supramolecular nanocomposite hydrogels exhibit multiple functions, including self‐healing, injectability, photothermal responsiveness, and conductivity, making them suitable for integration into flexible electronics. Highlights: Fe3O4@CB[8] nanoparticles serve as cross‐linkers for the nanocomposite hydrogels.CB[8] based host–guest interactions enable hydrogels to self‐heal.Fe3O4@CB[8] endow hydrogels with stretchability and photothermal responsiveness.Hydrogels exhibit injectability, NIR responsiveness, and conductive ability. [ABSTRACT FROM AUTHOR]