Aerogel – the lightest solid in its existence

Aerogel – the lightest solid in its existence

Aerogel, a material created on a bet between two scientists in the late 1920s, may be the most unique substance on Earth. It’s the lightest solid in existence — Guinness World Records even said so — but it can support 500 to 4,000 times its own weight
(depending upon whom you ask). A cubic inch of aerogel could be spread out to cover an entire football field. It’s breathable and fireproof, and it absorbs both oil and water. Aerogel is also amazingly strong, considering its weight. Aerogels can be great
electrical conductors, yet when made from different materials, they are also one of the best insulators ever known. So why don’t aerogels have the A-list name recognition they deserve?

Unfortunately, producing such a unique product takes an extraordinary amount of time and money, in part because only a very small amount of aerogel is made in each batch. Even though producing more aerogel at a time would bring its price down, the process
and materials alone come with a high price tag of about $1.00 per cubic centimetre. At about $23,000 per pound, aerogel is currently more expensive than gold!

Such a valuable product would seem to belong next to the diamonds and pearls in an heiress’s jewellery box. But aerogel is more likely to be found insulating a rocket or thickening paint than adorning wealthy socialites. While aerogels may not be as glamorous
as gold, they perform their tasks without peer.

In this article, we’ll explore what makes aerogels unique, from their discovery in California in the late 1920s, to their trip to collect space dust in 1999. We’ll also see what the future holds for aerogels and if there is indeed a way to make them more
cost-effective for the general public. Finally, we’ll show you how you can make your own aerogel — surprisingly, it can be done.

Read on to learn more about how aerogel first made an appearance and how this adaptable substance is made.

Aerogel begins as a gel, called alcogel. Alcogel is a silica gel with alcohol inside its pores. Simply evaporating the alcohol out of the silica structure would cause the structure to contract, much like a wet sponge will deform when left on a counter to
dry. Instead of relying just on evaporation, the gel has to be supercritically dried.

Supercritical drying is how the liquid "alco" part of the alcogel turns into a gas within the silica’s nanopores without the structure collapsing. The alcogel with its alcohol removed is now called aerogel, as the alcohol has been replaced by air. With only
50 to 99 percent of the original material’s volume, aerogel is a light, flexible and useful material.

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Posted by M. Omer Iqbal bhatti on Nov 3 2011. Filed under Sci-Tech. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry