According to a study by the University of California, contrary to what it seems, fine hair is less likely to break than thick hair. Their results indicate that the difference is due to their fracture mechanism.
This is good news for half of the population: beautiful hair is stronger than thick hair. research shows, University of California (U.S.) Published in the magazine today thing.
The work compares samples of eight different mammals: humans, bears, wild boars, horses, capybaras, wild boars, wild boars, giraffes and elephants. The thickness of hair ranges from 80 microns (µm) in diameter for humans to more than 350 µm for elephants or giraffes.
However, they are all based on a kind of outer layer called protein sharing a hierarchical structure epidermis Enclosed with an inner shell composed of many things fiber small. In each fiber, even a smaller fiber is embedded.This design can make hair resistant deformation.
To test the strength of each sample, the research team tied the single strands to a machine, which gradually forced them to break. To their surprise, they found that thin hair can withstand more stress before it breaks compared to thick hair.
As the lead author of the study, Wen Yang, professor of nanoengineering at the University of California, explained to Sinc, the secret lies in the way they destroy them.
He said that in the case of thick hair, his cut “follows a neat cut style, just like cutting fruit.” This is the case for hair larger than 200μm in diameter (such as wild boars, giraffes and elephants).
Human hair breaks in shear when under the microscope. /Yang Wen
This is not the case with fine hair. “Delicate hair tends to be Shear force. Yang said: “Due to stress, small jagged cracks will form in the material, just like a tree branch breaks in a storm.”
These cracks will spread, and the hair will not break completely until it is discovered.This type of fracture means it can withstand more pressure, so More resistant Rather than materials that experience normal fracture. This happens to hair with a diameter of less than 200μm (such as human, horse, and bear hair).
According to the results, these differences also apply to the same species. For example, the “fine hair” of children is stronger than the “thick hair” of adults.
Researchers believe that these results may help better design Synthetic material, Although he admits that the manufacture of materials inspired by people is still in its infancy.
“From the synthesis of extremely small materials to how to replicate the connection between each layer in a manner similar to natural hair, synthetic materials face many challenges that we cannot solve.” Yang said. “However, if we can make metal with this layered structure, then we can produce very strong materials for use as rescue ropes and structures.”
Yang Wen, Yang Yu, Robert O. Rich, Mark Meyer. “About the strength of hair of various species”. thing (December 11, 2019). https://doi.org/10.1016/j.matt.2019.09.019