Successfully manufactured super-flexible tape that bends like a thread, transmits light like a fiber optic cable cáp

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2021-07-12 19:54:40

Tapes have very poor flexibility, they are very hard and brittle and break easily. That’s why avalanches and ice breaks happen.

That’s also what makes this new study so amazing. Scientists have developed microscopic filaments of water ice that can be bent to form a circle – breaking the ice’s previous maximum deformation by a considerable margin and opening new opportunities for object discovery. ice handle.

Theoretically, the tape has a maximum elastic tension of about 15%. However, in the real world, the maximum elastic strain ever measured is less than 0.3%. The reason for this difference is that the ice crystals have an imperfect structure that increases their brittleness.

So a team of researchers led by a nanotechnology scientist, led by Peizhen Xu of Zhejiang University in China, sought to create ice with as few structural defects as possible.

The experiment involved a tungsten needle in an extremely cold chamber, at about minus 50 degrees Celsius, much colder than the previous test. Steam is released into the chamber and an electric field is applied. This attracted the water molecules to the tip of the needle, where they crystallized, forming a filament with a maximum width of about 10 micrometers, smaller than the width of a human hair.

Elastic band smaller than human hair

The next step was to lower the temperature from minus 70 to minus 150 degrees Celsius. Under this low temperature, the researchers tried to bend the ice fibers.

At minus 150 degrees Celsius, they discovered that a tiny filament measuring 4.4 micrometers across could bend into an almost circular shape, with a radius of 20 micrometers. This shows a maximum elastic strain of 10.9% – much closer to the theoretical limit than in previous attempts.

Even better, when the researchers stopped bending the ice, it returned to its previous shape.

Although ice may look the same to us, its crystal structure may differ slightly. Each configuration of the molecule in an ice crystal is called a phase, and there are quite a few of these phases. The transition between phases can occur under many different conditions related to pressure and temperature.

With flexible ice, the team recorded such a phase transition, from a form of ice known as Ih ice, the hexagonal crystal form of ice commonly found in nature, to rhombic ice II, which formed by compressing the Ih ice. This transformation occurs in the folds of ice microfibrils at temperatures below minus 70 degrees Celsius and is also reversible.

This flexible tape is also amazingly transparent, which means that microscopic ribbons could eventually be used to transmit light, similar to fiber optic cables. The scientists say the technology could be used to create small sensors capable of detecting air pollution.

“In short, the proven elastic ice can provide a platform for ice physics exploration and open up unprecedented opportunities for ice-related technology in a variety of fields.” said the researchers.

Reference: ScienceAlert

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