Multifunctional Stimuli-Responsive Hydrogels with Self-Healing, High Conductivity, and Rapid Recovery through Host–Guest Interactions

Self-healing hydrogels with multifunctionality as a type of fascinating material show potential application in various fields, such as biomedicine, tissue engineering, and wearable electronic devices. However, to combine the properties of autonomous self-healing property, high conductivity, excellent mechanical properties, and stimuli-responsive properties for hydrogel is still a great challenge. Herein, we present self-healing conductive hydrogels based on β-cyclodextrin (β-CD), <i>N</i>-isopropylacrylamide (NIPAM), multiwalled carbon nanotubes (CNT) and nanostructured polypyrrole (PPY). Among them, β-CD served as the host molecule, and NIPAM served as the guest molecule, CNT as the physical cross-linker and conducting substrate, and PPY as the highly conductive component, respectively. The obtained hydrogels exhibit high conductivity, self-healing property, flexible and elastic mechanical property and rapid stimuli-responsive property both to temperature and near-infrared (NIR)-light together. The excellent characteristics of the hydrogels are further illustrated by pressure-dependent sensors, large-scale human motion monitoring sensors and self-healable electronic circuit. Cytotoxicity test indicated that they are nontoxic to L929 fibroblast cells and C2C12 myoblast cells. Taken together, these multifunctional hydrogels are excellent candidates for stimuli responsive electrical devices, artificial organs, and so on.