6 metamaterials can change the world

Graphene may be the most famous "metamaterial" today, but aside from graphene, scientists have also created very interesting materials with the potential to change the world.

>>> Magicalmaterials that make you "squint"

Graphene - a material made from a layer of carbon atoms linked together by a honeycomb-shaped, ultra-light, ultra-thin and super-hard lattice - is perhaps the most anticipated material today. However, this is not the only "metamaterial" created in laboratories.

Here are six metaphors that have the potential to transform the future world:

Self-recovery materials - bio-plastics

The human body has the ability to repair itself very well. Ambient with artificial materials is not. Professor Scott White at the University of Illinois has been studying and making bio-resins that can heal themselves. Last year, White's lab invented a new polymer that could self-extract to fix a hole in visible size.

These polymers have a fluid circuit system that, when broken, spills, then clots like blood. Although materials exist to heal small cracks, the new material can repair a 4mm wide hole with cracks radiating around it. Human skin can heal this hole itself, but this is a breakthrough with plastic.

Video about a self-healing metal

The next step may be to study hard materials such as cement or self-healing metal. Of course creating materials is one thing, but mass production so that they are cheap and used in industry is another. In the near future, self-healing materials will probably be used primarily in space technology.

Thermoelectric materials - utilize waste heat

If you've ever felt a laptop warm up on your lap or hood warming up after running a long distance, you've witnessed a waste of heat. Waste heat is the inevitable result of running any device that uses electricity. An estimate shows that the amount of heat emitted is two-thirds of the total energy used. That's why many scientists have sought to utilize this waste heat. The answer is thermoelectric materials, which produce electricity from temperature differences.

Last year, Alphabet Energy in California (USA) introduced a thermoelectric generator that plugs directly into the exhaust of a conventional generator, turning waste heat into useful electricity. Alphabet Energy's generator uses relatively cheap and natural thermoelectric materials called tetrahedrite. Alphabet Energy says tetrahedrite can reach 5-10% efficiency.

Current thermoelectric materials still have high costs, so they are often used in projects such as spacecraft. Recently scientists have also experimented with a promising and high-performance thermoelectric material called skutterudite, which is a mineral containing cobalt. Skutterudite can become cheap and high enough performance to wrap around car exhaust, refrigerator or any other energy consuming device you can think of.

Perovskites - cheap solar cells

The biggest obstacle in using renewable energy sources is always money. Solar energy is cheap, but creating a power plant that uses solar cells from silicon crystals is still an expensive, energy-consuming process. The material that could change this is perovskites.

Solar cells are made from perovskites

Perovskites was discovered more than a century ago, but scientists have only recently realized its potential. In 2009, solar cells made from perovskites had 3.8% solar conversion efficiency. By 2014, this number had reached 19.3%. It may not sound like much compared to traditional silicon crystal cells with performance fluctuating around 20% but there are two other important points to consider. First, the perovskites performance has jumped just over a few years and scientists think it can increase further; and the second is much cheaper perovskites.

Perovskites are a material defined by a special crystal structure. They may contain any number of elements, for perovskites used in solar cells usually lead and tin. These materials are cheap compared to crystal silicon, and they can be sprayed on glass easily. Oxford Photovoltaics is one of the leading companies trying to commercialize perovskites, to put their excellence in the laboratory into the real world.

Aerogel - super light and hard

Aerogel is not like a real material. Although light and pure as air, they can easily withstand the heat of a blowtorch and the weight of a car. This material is almost like its name: a gel whose liquids have been completely replaced by gas. But you can see why it is also called "freezing smoke" or "green smoke".

Excellent insulation properties of airgel

The process of making this material is quite complicated. You need to have a piece of jelly, then take the liquid in it and still have to keep the outer structure of the jelly, then pump the gas inside to replace the liquid. There are many substances that can be pumped into an airgel, including graphene! The special structure of the airgel makes it very amazing.

This material is also extremely light

First of all, the airgel has extremely good thermal insulation, even close to the normal air. Aerogels made of silicon can withstand temperatures of more than 1000 degrees Celsius before melting. In addition, the airgel is very light, its own mass is even lower than helium gas. You can see a block of airgel made from super light graphene above.

Despite being so light, the airgel is very strong thanks to its special structure. A small aerogel can withstand the weight of a brick or even a car. The weakness of this material is that it is very brittle and expensive. Now scientists at NASA are experimenting with plasticizers for the spacecraft manufacturing technology, to take advantage of its thermal insulation for the process of moving through the atmosphere.

Super materials - stealth materials

If you've ever read Harry Porter, you'll probably remember the witch's invisibility cloak. In fact, metamaterials, with nanostructures designed to scatter light in special ways, could one day be used to make objects invisible, though possible. Will not be magic like Harry Potter's invisibility cloak.

The more interesting thing about this metamaterial is that they not only redirect light in the visible spectrum. Depending on the way and structure of the metamaterial, it can also redirect microwaves, radio waves, or T waves (located between microwaves and infrared waves in the electromagnetic spectrum). Any part of the electromagnetic spectrum can be controlled by metamaterials.

This "stealth" metamaterial can be applied in medical T-ray scanners, security scanners or compact antennas that can change properties very quickly. However, to apply this material in commercial products, perhaps we will have to wait a long time.

Stanene - 100% efficient conductor

Like graphene, stanene is also composed of a single atomic layer. But instead of carbon, stanene is made of tin and this makes the difference of stanene that graphene cannot achieve: conductive with 100% efficiency.

Stanene was first theorized in 2013 by Stanford professor, Shoucheng Zhang, who specialized in predicting the electronic properties of materials such as stanene. According to his model, stanene is a topological insulator, meaning that its edges are an electrical conductor and its insides are an insulator. (Think of it as a chocolate ice cream bar. Chocolate is electrically conductive, and ice cream is insulated).

This means that stanene can conduct electricity with zero resistance, and it is important right at room temperature. The properties of stanene have not yet been tested experimentally - making a single atomic tin plate is not an easy task - but many of Zhang's predictions about other topological insulators have been proven correct.

If stanene predictions are proven, it can revolutionize the microchips inside all your devices. Specifically, the chips can get more power. Silicon has a limit of not being able to run too fast because it will quickly heat up. Stanene, with 100% conductivity, will not have such problems.