This Futuristic Material Is the World's Lightest Solid
Aerogel is a material that comprises of 97% air and is said to be the lightest existing solid to be created on earth as it manages to maintain all the structural properties of a solid. This material has quite impressive physical and chemical properties which have puzzled many people in the science community as well as got them curious to learn more about this strange material.
Wondering where Aerogel got its name?
The name Aerogel was formed from two words which are: air and gel, that’s basically the entire history to its name. It was invented by a guy called Samuel Stephens Kistler due to his fascination with jelly as it is combined to act as both a solid and liquid. How jelly works is that it has a porous gelatin structure that holds in the water, therefore creating a pseudo substance. Samuel was experimenting by replacing the water content with air to see what would happen, however, if the gel was simply dried the solid structure would contract and therefore lead to cracks. Samuel also understood that the gels with a high microporous structure can collapse due to high surface tension forces exerted by the liquid.
He then tried to find another way to remove the liquid without damaging the solid structure. For this experiment, he decided to use alcohol instead of water. Due to the nature of alcohol, when it's converted to a supercritical state of being between a gas and a liquid and it will not have surface tension. Silica was used to make the microporous structure of the solid. The first Aerogel was formed once the alcohol evaporated away. To explain this in simpler terms Aerogel is made from when water or any solvent is removed from a gelatinous structure.
Physical properties of Aerogel
Aerogel has a very low density and a translucent look due to the fact that most of its material is air. Even if a human-sized statue was made out of aerogel it would only weigh about 1 pound, this is why it’s known as the lightest solid on earth.
Aerogel has very unique properties, one being its incredible insulation against heat (0.023 W/mK at 100˚C). Another would be its excellent acoustic properties, boasting 10 to 1000 times better sound insulations than polyurethane forms.
Aerogel’s structure comprises only about 3% solid materials (silica and carbon) and it is therefore very fragile.
How is Aerogel made?
As previously discussed aerogel is made by removing water contents from a gel and replacing it with air. Sol-gel is the name of the process that is used in modern times to produce Aerogel.
In 1983 this new manufacturing process was developed by a guy called Arlon Hunt and the Microstructured Materials Group. Something called a Tetraethylorthosilicate was used for Aerogel production and it is said to be much another method called the TMOS method that was used until this new method came around.
Another development method included the use of liquid carbon dioxide instead of alcohol as the base solvent. Using the TMOS method and alcohol in Aerogel products made it a very dangerous process. For example: When this method was used in Sweden it caused an explosion that destroyed an entire Aerogel production plant.
What are the applications of Aerogel?
The physical characteristics of Aerogel are one of the most studied materials that were made by man and nowadays you can find Aerogel in many things such as cosmetics, paints, wetsuits, etc. Since the invention of Aerogel, its use has only been widening in the aerospace industry. A comet was caught as well as interstellar dust in NASA’s Stardust mission due to the use of Aerogel. The use of aerogel as an insulating material was also able to keep the Mars Exploration Rover warm during its mission.