Bioinspired hydrogels with muscle-like structure for AIEgen-guided selective self-healing

Living systems, including human beings, animals, and plants, display the power to self-heal spontaneously after being damaged. The self-healing is usually selective, which means that the healing efficiency is related to the spatial distribution of dynamic interfacial interactions of the two rupturing surfaces. Current artificial systems use noncovalent interactions or dynamic covalent bonds to prepare self-healing materials. However, they can only show nonselective self-healing due to their homogeneous internal structures. Herein, we report the construction of a composite hydrogel Gel-C consisting of three different self-healing hydrogels (Gel-Y, Gel-G, and Gel-O) through the use of classic bilayer hydrogel technology. When the composite hydrogel was cut into two pieces, the relative orientation of the parts was rotated through different angles to study the differences in self-healing. Owing to the heterogeneous internal structure of the composite hydrogel and the recognition specificity of each included hydrogel, the interfacial dynamic interactions distribution of the two rupturing surfaces is diverse. The results of tensile tests demonstrated that these rotated samples exhibited different self-healing efficiencies. This system realized the transformation of artificial materials from nonselective self-healing to selective self-healing, providing inspiration for the development of novel biological materials and engineering materials.