Throughout history, human production and daily life have relied heavily on various materials. Objects composed of diverse materials are bound to undergo wear and tear with use.

Despite the existence of several effective repair methods—such as welding for metal and gluing for plastic—these repairs often demand significant time and labor, and they may struggle to completely restore the material's original appearance and performance. As a result, in recent years, scientists have introduced the concept of "self-healing materials".

Self-healing materials represent an innovative class capable of repairing themselves upon sustaining damage. Their defining trait lies in their ability to detect signs of damage and promptly initiate self-repair. By doing so, these materials can mitigate maintenance expenses, prolong the lifespan of objects, and ensure their safety and integrity. Self-healing materials find applications across a broad spectrum, spanning from electronics and automobiles to airplanes and building materials.

When a person sustains a cut or wound, their skin naturally initiates a healing process. This primarily relies on platelet coagulation within the blood to promptly stop the bleeding, facilitating the eventual healing of the wound. Drawing inspiration from this natural process, scientists have engineered a biomimetic material that emulates the principles of human wound healing. By incorporating various repair agents, adhesives, and other substances within the material, it achieves the objective of self-repair.

Based on their repair mechanisms, self-healing materials can be categorized into two main types. The first type involves dispersing or incorporating functional substances within the material, typically in the form of fibers or capsules containing chemicals. The second type entails supplying energy to the material through processes such as heating or exposure to light, enabling it to crystallize, form a film, or undergo cross-linking for repair. Building upon these two mechanisms, self-healing technology has found applications in concrete, metal, and polymer materials.

Take, for instance, concrete self-healing materials. These materials, rooted in cement, incorporate steel wire staple fibers to bolster toughness. The essence of their self-repair lies in embedding glass hollow fiber tubes within the material and injecting a highly viscous repair agent into these tubes. As cracks develop within the cement matrix, sections of the fibrous tubes rupture, releasing the repair agent. Over time, aided by the repair agent, the cracks re-bond. It's conceivable that employing this concrete self-healing material in bridge and construction applications could significantly enhance the lifespan and safety of building materials.

Polymer materials employ "light" to accomplish self-healing, utilizing the "energy supply" from ultraviolet irradiation for the self-repair process. Its principle relies on the unique bonding between sulfur and carbon atoms within the material. When exposed to light, this initiates a chain reaction, allowing the atoms to repeatedly form covalent bonds with each other. This polymer metamaterial finds practical applications in everyday life, such as tooth fillings, due to its remarkable adaptability to various shapes and rapid hardening when exposed to ultraviolet light. In the future, the widespread utilization of this polymer metamaterial is anticipated across diverse sectors including construction, machinery, electronics, automobiles, aerospace, and others.

As we marvel at the remarkable self-healing capabilities of these materials, it's imperative to recognize the profound significance of this technology in enhancing material utilization rates and prolonging material lifespan. Such advancements hold immense promise for resource conservation and the pursuit of sustainable development.