We all know that the useful life of materials is limited since any object, component or machine, at a certain moment, will end up breaking. This happens constantly in all kinds of applications: asphalt cracks, cracks appear in the cement, protective paints get damaged and allow corrosion to appear, there are even pieces that break into pieces.
The materials industry is continually investigating to find harder and more resistant materials to prevent them from breaking easily, but in the end, if a defect appears, the result is always the same: the failure of the component. However, what if these materials could repair themselves, once damaged? Well, stay tuned because they exist and are Self-healing materials.
What are Self-healing or Self-healing materials?
Self-healing materials are those smart materials that, after suffering damage, damage, cut or fracture, can return to their original state causing their own repair.
These materials have been developed, like many others, based on nature, and more specifically, on the regenerative system of living beings. If a person suffers a cut, their own immune system will close said cut and with the passage of time, it will proceed to heal it, making everything return to its original state.
Self-healing or self-healing materials work on the same principle, closing the “wound” of the material and returning it to its original state, with the advantage that the process usually lasts between a few minutes to a few hours, depending on the type of material. -healing that has been used.
Types of Self-healing materials
As we have seen, these materials try to imitate the response of the immune system of living beings to repair themselves, however, they have different types of mechanisms with which to achieve this objective:
This is the simplest type of self-healing material, and in turn, the most versatile way to transform a common material into a self-healing material. To achieve this, microcapsules have to be added within the material. When a crack, cut, fracture or damage occurs, the microcapsules break and release compounds that fill the damage and solidify, closing the break and returning the material to its original state.
The disadvantage of this type of self-healing materials is that the number of times that it can be repaired is limited, since when all the microspheres in a certain area break, it loses the possibility of recovering.
This type of self-repairing material is very similar to that of microcapsules, since it is also based on the release of compounds that fill in the damage produced and solidify to repair it. However, instead of having spheres dispersed inside the material, what they have are channels, which store said compounds and can be arranged in 1D, 2D or 3D.
These channels release repair products when they detect material damage. In addition, they can be connected to an external tank that can provide repair liquid for a longer time, so the self-healing functionality is maintained for longer.
This last type of self-healing materials covers a wide range of materials, which have the characteristic of being able to return to their original shape by themselves, either through a contribution of external energy, such as light, heat. , or its own nature.
This type includes, for example, shape memory materials, which can be returned to their original shape by applying heat; ionomers, which reorganize their physical structure to self-repair their damage and even seal it; or other types, among which are included some thermoplastic materials that, when heat is applied, go to a solid-liquid state and flow until the cuts or cracks generated are filled and sealed.
These types of materials provide the advantage that their self-healing behavior is almost infinite as long as they have the necessary conditions for their self-repair process to begin (heat, light, sufficient material, etc.). On the contrary, they have the disadvantage that these materials have to be specifically formulated, so that they will only serve certain applications and cannot improve the performance of an existing material. We show you a Project that we have carried out in ATRIA with these self-healing materials. The results are amazing!
Applications of Self-healing materials
Some of the applications of this type of materials are the following:
If a self-healing material is scratched, you can close or fill the scratches, leaving it as if the material had never been scratched. This, for example, is being applied in coatings and paints for car bodies, where scratching leads to the re-painting of the entire car or a part of it. Another application is for example mobile phones, where some models have already incorporated self-repairing materials to keep both screens and cases scratch-free.
There are a large number of materials and elements that, when cracked, lose their integrity or their functionality, requiring their immediate replacement. With self-healing materials it is possible to extend their useful life, as could be the case with aircraft wings, asphalt on roads or construction elements, where their inspection and repair is very expensive and laborious.
A break in any component usually means its immediate removal and the need to use a replacement, or failing that, repair it to rejoin the separate parts. Self-healing materials have been developed which, by exerting pressure between the separated segments, their union can be achieved as if glue or solder had been applied between them, showing the same resistance in the union as before it was divided.
Any damage that occurs on the surface of a paint, coating or protective coating of a metallic material, can trigger the appearance of corrosion. This is avoided if said protective layer can self-repair in a short time, again isolating the metal substrate from the outside environment, and thus protecting it from corrosion. These types of paints and coatings are already on the market today and may represent a big change in this industry in the coming years.
These are some examples of applications and self-healing materials that are already on the market. In addition, as we have explained, in many cases the number of applications can be unlimited, which is a great advantage.
What did you think of our blog about Self-healing materials? Do you need to improve your material to avoid scratches or damage? Do you want to look for a new material that avoids its constant repair? Contact us!
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