Aerogels - New And Improved

Aerogels are among the lightest solid materials known to man. They are created by combining a polymer with a solvent to form a gel, and then removing the liquid from the gel and replacing it with air. Aerogels are extremely porous and very low in density. They are solid to the touch. This translucent material is considered one of the finest insulation materials available.

Aerogels were invented way back in 1930, but recently NASA’s Glen Research centre in Cleveland have devised new methods to produce new and improved type of aerogels that in every way are superior from the old fashioned aerogels. Aerogel preparation is a complex technical process. Aerogels are primarily made of silica, the silica is combined with a solvent to create a gel. This gel is then subjected to supercritical fluid extraction. This simply means taking out all the moisture present in it. This supercritical fluid extraction involves introducing liquid carbon dioxide into the gel. The carbon dioxide surpasses its super critical point, where it can be either a gas or a liquid, and then is vented out. This exchange is performed multiple times to ensure that all liquids are removed from the gel. The resulting material is what we call aerogel.

Aerogels provide very effective insulation, because they are extremely porous and the pores are in the nanometer range. The nano pores aren't visible to the human eye. The existence of these pores makes the aerogel special giving it the best insulating properties. The small pores and poor gas phase heat conduction prevents the air molecules to travel through the aerogel resulting in poor heat conduction thereby giving it very good insulting properties.

Aerogels are a very favourite thing for all the space enthusiasts. Traditional aerogels was used in many previous space expeditions like providing insulation to the Mars Rovers. Commercially also they are used but mainly in pellet form or in composite form with other materials. Silica-based aerogels are very light, as they are about 95% porous. Silica aerogels are very useful, but they have limitations as they are very fragile.



NASA's Glenn Research Center has developed two cutting-edge methodologies that revolutionize aerogel technology. The first innovation is a method of creating aerogels that are reinforced by polymers. The method changes the surface of the gel as it reacts with a polymer. The result is that the interior surface of the aerogel gets a thin layer of polymer, which greatly strengthens the aerogel. The second innovation is a method of creating aerogels made completely of polymers. These polymer-based aerogels are extremely strong and flexible. They can also be made into a bendable thin film. ‘Polymer enhanced aerogels and polymer based aerogels have numerous potential applications, both in space, on distant planets and on our own Earth’ is NASA’s vision about these aerogels.

They are light, durable and extremely effective at insulating and preventing heat transfer. NASA‘s research wing have invented something which has the potential to serve as a base for something exciting and revolutionizing in the distant future.
Source: ?NASA Space News, International Space Station Shuttle Missions Google Earth Science Technology : Aerogels: Thinner, Lighter, Stronger