It weighs less than air and is extremely strong, yet flexible enough to bounce back to its original shape, after being compressed. And, it does not float away either, because a 10cm×10cm×10cm cube does not displace 1000 cubic centimeters of air, since a lot of air stays in the pores of the 'sponge'. But best of all, it can absorb up to 250-500 times its own weight of oil at a rapid pace of 68.8 grams per second. This is not a material scientist's dream, but a description of the most recent 'lightest' solid created by a research team from China's Zheijang University.
Unveiled in the February 18th online edition of Advanced Materials, this latest creation dubbed aerographite is a member of the family of the world's 'lightest' solids known as aerogels. First there was the 'frozen smoke' aerogel that boasted a density of 4mg/cm3, then came the micro lattice material that sported a density of 0.9mg/cm3 and now, less than a year later, is this aerographite whose density is a mere 0.16mg/cm3.
First created in 1931, by American scientist Samuel Stephens Kistler, aerogels, are formed when water is removed from wet gel, leaving behind a complex web of nano-particles - A solid so light and strong, that a block of aerogel the size of a human, would only weigh 455gms (about one pound), yet, be capable of supporting an object weighing half a ton.
For many decades, aerogels were made from silicon dioxide (the main ingredient in sand), metal oxide and polymers. However, because they were expensive to produce and extremely fragile, their usefulness was limited to specialty projects like capturing stardust in orbit or insulating the Mars Rovers.
In the last two years however, researchers have figured out how to the make aerogels from carbon nanotubes - wisps of carbon so small that about 50,000 of them would fit on the width of one human hair. They are stronger, more flexible and largely porous, which opens them up to a lot of potential uses ranging from electronics to insulation and of course, oil-spill cleanup. Besides being able to absorb a lot more of the toxic liquid they also don't have to undergo the expensive process of separating out the oil that is required when conventional materials are used - Carbon aerogels can be just squeezed or even burned and then, reused!
Resources: fastcoexist.com, dailymail.co.uk