Aerogel. Our favourite almost there material
AeroGel – Frozen Smoke, so called as it has a transparent smokey look – has added another use to its growing list of can do’s. Scientists at the University of Southern Florida are working to develop batteries using the material. There is something impossible about this strange material, something very cool.
So what makes AeroGel so great? Firstly it’s 99.98% air but still manages to be a solid, there is literally nothing too it. It has the texture of polystyrene when you hold it but it looks fairy floss. It is a great insulator of both heat and electricity. Currently it holds 15 Guinness World Records for various properties, worlds lightest solid, worlds lowest density solid, worlds highest insulation value. It is an extreme material, it doesn’t do that many things but what it does do is always a world record.
The internal surface area of Aerogel makes it exceptionally useful for many tasks. To understand Aerogels internal surface area picture a sponge with all of its bubbly looking holes. The spherical walls of the bubbles are its internal surface area. In a sponge the bubbles walls take up nearly 40% of the space inside the sponge. In Aerogel the structure is similarly bubbly but the cell walls take up .02% of the internal space and the bubbles are much smaller with many many more of them. This gives Aerogel the highest internal surface area of any known substance. There are a few designer substances out there that might one day beat Aerogel on internal surface area but none of them are mass producible like Aerogel. It is the internal surface area that makes it an ideal candidate for batteries where the power is stored on this internal surface and catalytic converters that use the internal surface to do its work.
The process for making Aerogel is in principle quite simple but in practice quite difficult and time consuming. In essence a gel containing the Silica is put into a high pressure and temperature vessel – pressure cooker – and the liquid part of the gel is replaced with a gas. It is possible to assemble the equipment yourself and make your own areogel but it is dangerous and takes 4 days to manufacture. Large factory based facilities have become very efficient at making Aerogel now-days, this has dropped the price and will allow it to be used in many new and fascinating ways. Home insulation is the latest boom industry for Aerogel, where it allows the builders to use much thinner layers of insulation and still achieve much better heat/cold barriers.
Silica based – sand – Aerogel is currently the most common form but many materials have been tested and used since it was first discovered in 1930′s. While carbon Aerogel is looking promising for electronics. Interestingly Aerogel can be made from many different substances and it inherits many of the good properties of those substances. Use metals and it becomes very conductive, use silica and it becomes very non-conductive. With many of it’s properties so changeable it’s uses will grow over time.
So keep an eye out for Aerogel, it will save you on heating or cooling, make better batteries and generally improve our lives. It is the impossible material that you can expect to see a lot more of in the coming years.
Pictures via of NASA