The Miracle Material
So what exactly is aerogel? While some materials may exhibit a low density, high thermal resistivity, or high strength-to-weight ratio, only aerogel can claim all of these properties at once . The name aerogel comes from the combination of the Greek word “aero”, meaning air, and “gel”, since aerogels are derived from gels. Normally, a gel is approximately 99% liquid, while the remaining 1% is a solid network that spans throughout the liquid and can allow the gel to maintain its shape. With a density only three times that of air, aerogel is what is left after replacing the liquid contents of a gel with a gas — without shrinking it . As shown in Fig. 1, the result is an opaque blue solid that is composed of anywhere from 95-99% air. The texture of aerogel is similar to a fine, dry sponge, but feels much lighter . In fact, aerogel holds the record as the lightest solid in the world. When pressed softly, aerogel will return to its original form, but when pressed harder, a dimple forms. Put aerogel under too much pressure, however, and it will shatter like glass into many tiny pieces. Although it was first produced over 70 years ago, it has taken recent research and applications for it to be hailed as a “miracle material” .
It Started With a Bet
Aerogels would not make another major appearance in the scientific world until the 1980’s, when a group of researchers led by Arlon Hunt of Lawrence Berkeley Laboratory came upon a sample . Hunt and his team worked to improve the material’s clarity, production methods, and thermodynamic properties. One of the first projects the team worked on was finding a safer way to produce the substance. The base chemical used to make aerogels, tetramethylorthosilicate (TMOS), is highly toxic and can easily damage the human eye. At the time, it was known that aerogels could be made using a safer compound, tetraethylorthosilicate (TEOS), as a substitute for TMOS, but the resulting aerogel was smaller and less clear. Hunt’s team experimented with the other chemicals involved in aerogel production and was able to achieve a clearer and less shrunken TEOS aerogel.
One Substance, Many Uses
Other predicted uses of aerogel include armor for military vehicles and a “sponge” utilizing aerogels’ pores to soak up lead and mercury spills in the ocean. The idea of aerogel armor came after experiments showed a metal plate with a protective aerogel layer was found to sustain little damage when exposed to a blast of dynamite. Also, Aspen Aerogels has taken their clothing insulation a step further, and plan to fabricate a space suit for a manned mission to Mars in 10 years. Scientists at the company believe that the insulation will be able to withstand temperatures as low as -130 C. There may be another “green” use of aerogels as well, as research has found that platinum-based aerogel can speed up the production of hydrogen for use as fuel . If implemented successfully, this technology would be able to provide cheaper alternative fuels to combat the high cost and limited supply of oil.
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