The lightest solid ever developed: Graphene Aerogel

THE LIGHTEST SOLID EVER DEVELOPED: GRAPHENE AEROGEL

Kindzerskyy Oleksandr, Hulak Oleksandr

National Technical University of Ukraine “Kyiv Polytechnic Institute”

Material science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This relatively new scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. With significant media attention focused on nanoscience and nanotechnology in recent years, materials science is becoming more widely known as a specific field of science and engineering. Many of the most pressing scientific problems that are currently faced today are due to the limitations of the materials that are currently available and, as a result, breakthroughs in this field are likely to have a significant impact on the future of technology.

For many years, scientists wanted to create a super-lightweight materials that would not be fragile and brittle. The first significant step in this area was creation of aerogel. Developed in 1931, «frozen smoke» held the title for world’s lightest material for more than eighty years. It’s basically just a gel made from silicon, except all the liquid has been taken out and replaced with gas instead. If you hold a small piece in your hand, it’s practically impossible to either see or feel, but if you poke it, it’s like styrofoam.

As research into aerogel continues, scientists are discovering ever-lighter variations. First, there was carbon nanotube aerogel, with a density of 4 milligrams per cubic centimeter. Then along came silica aerogel, which weighed in at 1 milligram per cubic centimeter and garnered 15 entries in Guinness World Records.

Last year aerographite jumped into the number one spot. One cubic centimeter of the stuff weighs just 0.18 milligram. Aerographite was heralded with much fanfare when its discovery was first documented, but its reign was to be a short one.

However in March, 2013 team of scientists at China’s Zhejiang University went after — and broke — the lightness record set by aerographite. Their discovery is a spongy substance made from freeze-dried carbon. They’ve dubbed it graphene aerogel, and it weighs in at a tiny 0.16 milligram per cubic centimeter.

For reference, the density of air is 1.2 milligrams per cubic centimeter — so the new material is 7.5 times lighter than air. It’s twice as heavy as hydrogen — the lightest element there is — but beats out helium, which has a density of 0.1786 milligrams per cubic centimeter.  In its pure state, the substance is a two-dimensional crystal of pure carbon atoms arranged in a honeycomb lattice. That makes it the thinnest material ever made, yet 200 times stronger than steel.

Gao Chao’s team had already been building macroscopic graphene materials in one and two dimensions; to create the new aerogel, the researchers branched out into the third dimension, using a new method of freeze drying the solutions of carbon nanotubes and graphene to create malleable carbon sponges.

The end result is an aerogel that weighs just 0.16 milligrams per cubic centimeter, and has truly superb elasticity and absorption. The graphene aerogel can recover completely after more than 90% compression, and absorb up to 900 times its own weight in oil, at a rate of 68.8 grams per second. The absorbed oil, water, and the graphene aerogel itself would be able to be reused after the cleanup effort. With these two features combined, lead researcher Gao Chao hopes that the material might be used to mop up oil spills, squeezed to reclaim the oil, and then thrown back in the ocean to mop up more oil.

Beyond filtration, graphene aerogel might be used as insulation — or, if it’s as conductive as aerographite (which seems likely), graphene aerogel could enable the creation of lighter, higher-energy-density batteries. Also it is a superb conductor of electricity — far better than copper, traditionally used for wiring — and is the best conductor of heat on the planet.

The team is currently hard at work developing other wonderful uses for the substance which revolve around this absorbency and elasticity.

“Maybe one day when oil spill occurs, we can scatter them on the sea and absorb the oil quickly. Due to its elasticity, both the oil absorbed and the aerogel can be recycled,” Gao Chao said in a statement. Until that day comes, the Chinese team are still exploring its applications, of which, this writer is sure there are many.

The full results of the project can be found published in Nature, titled «Solid carbon, springy and light».

A topic we touched in this work is quite interesting because it is one of the latest world achievements. As we can see, Material science does not stand still. Scientific progress accelerates by new technologies. Our work confirms this fact.

References:

  1. http://www.dvice.com/2013-3-28/world-has-new-lightest-material-graphene-aerogel
  2. http://www.cnet.com.au/graphene-aerogel-is-the-new-worlds-lightest-substance-339343765.htm
  3. http://inhabitat.com/newly-developed-graphene-aerogel-is-the-worlds-lightest-material/
  4. http://imgur.com/gallery/xlVTq
  5. http://en.wikipedia.org/wiki/Aerogel

 

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