A student at the University of Tokyo, Yu Yanagisawa, was working on the development of a new adhesive when, by accident, he obtained a result very different from his initial goal.
Yanagisaw inadvertently cut the low molecular pressure polymer he worked with. However, it did not take him long to notice that the broken material returned to join the shortly after, if kept under light pressure.
“It is very robust from the mechanical point of view, while it can be quickly repaired by applying pressure on fractured surfaces,” says Professor Takuzo Aida, director of the Japanese team.
The researchers conducted further tests to verify that this fact had not been the product of a mere chance. And, in fact, it was not about chance: the new low molecular pressure polymer has properties of self-repair never seen before.
Unlike other polymers, which also have the ability to self-repair, this new material does not need high temperatures for the reconstructive process to take place. Until now, a temperature of about 120 ° C was necessary to reorganize its structure.
On the other hand, the glass that is made with this new material can be repaired by pressing with the fingers (at a temperature of approximately 21 º C) the broken pieces for a few seconds, recovering their original strength after a few hours.
Good, Cheap and Ecological
Expanding the range of materials that can be repaired is a major challenge for sustainable societies. High molecular weight non- crystalline polymers generally form mechanically robust materials, which, however, are difficult to fix once they are fractured.
Materials such as self-healing rubber had already been developed, but scientists say that it is the first time that a hard substance is created that can be reconstituted at room temperature.
The applications that this type of polymer can have cover a wide range of possibilities. One of the closest and immediate utilities is in the technology that we use every day: this glass has the capacity to be used for different electronic devices, such as the screens of our phones or other fragile devices.
As a general rule, the repairs of these crystals have always been quite expensive, and the protectors must be changed regularly whenever they suffer a fracture. Therefore, this discovery seems to be a great solution to the problem of the screens of phones.
“I hope that the glass that repairs itself becomes a new environmentally friendly material, that does not need to be thrown when it breaks,” Yanagisawa emphasizes, contributing the ecological vision of this polymer.