Graphene Aerogel: the lightest material on earth

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Tougher than steel and seven times lighter than air, a super strong creation by the name of graphene aerogel is now the world’s lightest material. Graphene aerogel is made from freeze-dried carbon, graphene, and aerogel, but holds the texture of a sponge-like solid. Yet, it’s solid, is so delicate that it can easily balance on top of a wispy cotton ball.



Graphene Aerogel into context

Developed by Professor Gao Chao and his team of scientists at Zhejiang University in China, and Professor Dong Lin of Kansas State University, graphene aerogel weighs only 0.16 milligrams per cubic centimeter. As a comparison, the density of the air itself is 1.2 milligrams per cubic centimeter. This is the least dense 3-D printed structure to ever exist, according to the Guinness World Records. The previous title-holder of the most lightweight material on the planet, aerographite, has officially been revoked by 12%. This brawny, but plush-looking creation can be balanced on top of even the most gentle flower petals. Plus, the structure’s density is twice the size of hydrogen, making it quite flexible.

The starting point of this ultra-light design is to recognize graphene’s innovative structure. Graphene was discovered in 2004 and it is the world’s thinnest material. One printed sheet of graphene is as thin as a single atom. The coordinated carbon atoms on a sheet of graphene also contain properties to conduct electricity. It’s mainly used in aerospace industries and in batteries. Once it’s paired and 3-D printed with its sidekick aerogel, it becomes a beacon of energy storage and manufacturing freedom.

Phisical properties

Aerogels aren’t a new idea since scientists introduced the concept back in the 1930s. They’re known for primarily being made out of silica and being effective insulators. Aerogel is so microscopically porous, each nanopore is able to collectively work together to provide insulation. As new scientific theories developed, aerogels often became produced by the sol-gel method, where a solid polymer gel would become dehydrated to the point where it dissolves and only the gel remains. The gel is then dehydrated and the remaining water content is replaced by a gas. Simply put, that gas is usually air, rightfully naming it aerogel. This isn’t necessarily the only process to create aerogel, although it is the most common.

Aerogels have been successfully used in many forms, like providing insulation on a Mars rover or being used by NASA to create durable space suits. Aerogels such as aerographite may be produced through the template method. This alternate method includes growing carbon on a template of zinc oxide crystals and then having the zinc oxide removed in an oven, resulting in leftover carbon aerogel. In either process, the air content of aerogel on its own is 99.98%, making it extremely light and useful for insulation purposes.

The specialty of graphene aerogel comes from the unique method of dissolving polymers through freeze-drying. The core of this method stems from the original sol-gel procedure, but it’s not exactly the same. Researchers at Zhejiang University recognized the sol-gel method as being insufficient once the gel was remaining in the drying stage. So, they began using the freeze-drying method.

The freeze-drying method required the researchers to mix a solution of graphene and carbon nanotubes. These become molded together and dried by freezing. That freezing is what dehydrates the solution, leaving very thin sheets of remaining graphene. Those single-atom-thick layers of graphene are supported by air and nanotubes, creating the marvelous material that is graphene aerogel.

A little 3D printing magic

Researchers have also stated that 3-D printing does not have to be limited by size, so creating larger sizes of the material is definitely a possibility. Controlling the shape and size directly controls the electrical and mechanical properties, too. Even a cubed meter is within reason to generate through the use of 3-D printing.

Graphene Aerogel

The 3-D printer uses a modified inkjet printer with two nozzles, enabling researchers to create complex structures and shapes with less material. Scientists are able to print the droplets of the graphene oxide and water mixture. This is done on a cold plate that is minus 20 degrees Celsius. Once this method creates an ice structure of graphene and frozen water, researchers remove the ice by placing these 3-D materials in a freeze dryer. Finally, that 3-D graphene aerogel is able to maintain its form at room temperature and can continue being printed over and over again.

Graphene Aerogel applications

The use of this new material is extraordinary and can be used to invent the next generation of clothing, batteries, electronics, or semiconductors. This is just the tip of the iceberg. Graphene aerogel is expected to shape future space exploration and have an impact on in-space manufacturing. Since the material is so lightweight, it could act as an insulator in aircraft engines without impacting total weight. Scientists are also eager to discover how these structures will behave in microgravity. It could potentially advance the development of both thermally insulated materials and sensory materials. If researchers could figure out how to manufacture graphene aerogels in microgravity, the way humans explore space and heal environmental issues could dramatically change.

Researchers are also deeming graphene aerogel as an immediately necessary aid for environmental hazards like oil spills or dangerous chemical leaks. A gram of aerogel can absorb 68.8 grams of organics per second. The material has the phenomenal quality of absorbing up to 900 times its own weight in oil and water, while being able to return to 90% of its shape after use. This would mean that graphene aerogels could potentially soak up a damaging spill and then simply be picked up and drained afterwards. Since it nearly returns to its original size, there is also a possibility that the material could be reusable.

Although it would be invaluable to witness graphene aerogel become popular to the masses, advancements towards simplifying the manufacturing process are currently limited. The pricey costs of materials also come into play. With time and company investment opportunities, perhaps graphene aerogel will become more commonly known for its use in space and on Earth.

Other useful resources:
Graphene Aerogel world’s lightest substance
World’s lightest and strongest material

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