Airgel. Colloidal gel-like substance, in which the liquid component is exchanged for a gas , obtaining as a result a very low density solid (3 mg / cm3 or 3 kg / m3) and highly porous, with certain very surprising properties, such as its enormous capacity for thermal insulation.
Summary
[ hide ]
- 1 Main features
- 2 Manufacturing
- 1 Process
- 3 types
- 4 Aerial constructions
- 5 Applications
- 6 Sources
Main features
- Ultra light: as it is made up of 90% to 99.85% air, its density is three times that of air .
- Ultra resistant: this material is capable of supporting a thousand times its own weight.
- Ultra insulating: thanks to its porosity it acquires characteristics that make it resist very low and high temperatures. It protects 39 times more than the best fiber glass .
- Appearance: It has a ghostly appearance, very similar to glass.
- Popular names: solid smoke, frozen smoke.
- Refractive index: it is just 1.0 and is the lowest for a solid.
- Creator: Samuel S. Kistler.
- Year of creation: 1931 .
- Development year: around the 60s.
Manufacturing
To make the aerogels, a gel is usually made based on silicon (it can be replaced by carbon , titanium , among others to modify the properties) and then the water inside the bubbles is drained .
Process
Subjecting the material to a specific temperature and high pressure, so that the surface tension of the liquid does not collapse the bubble. That is the problem of aerogels; its expensive and difficult manufacture. The most appropriate liquid to dissolve the material that will constitute the bubble is alcohol , yet improvements have been obtained in the methods that aim at a great reduction in manufacturing costs in the not too distant future. Currently, different types of aerogels can be manufactured, using silica , alumina , chromium oxide , tin or carbon as a base.
Types
Part of the silicon can be substituted by other materials: carbon, titanium, etc., which give it different properties:
- 2mm thick titanium based aerogels that can stop a bullet. V.
- Vessels that after being broken, dissolve in the water and do not contaminate, as they are basically sand.
- Window panels that better insulate from cold, heat or noise.
- Very light spacecraft fuel containers or ablative plates to withstand atmospheric reentry.
Aerial constructions
Its low weight and the ability to function as a thermal insulator make it suitable for the construction of aerial structures, which would allow them to float indefinitely in the air. For example, an airgel-based geodesic dome would be so light that the temperature difference between the indoor and outdoor air would suffice to make it float.
This would reduce the total weight of the structure (and its cost), since it does not need support beams. The translucent airgel does not allow heat leakage but it does allow the entry of solar radiation, just like a crystal does, which allows indefinite floating while in the sun . The height of the dome can be varied simply by increasing the indoor / outdoor temperature differential
Applications
This material can be used to protect astronauts from temperatures as low as -130c; It is also being tested for explosive and bomb-proof armor and covers, as well as military vehicles. In the lab, a 6mm airgel-covered metal plate was left almost intact against a direct blast from the 1kg dynamite explosion. Airgel has millions of tiny pores on its surface which makes it ideal for absorbing pollutants from water.
Kanatzidis has created a new version of the airgel designed to absorb lead and mercury from water. Other versions are designed to absorb oil spills. Airgel is also being used for more everyday uses as insulation for places where air conditioning or heating is needed, in addition to insoles for climbing boots and sleeping bags filled with this material.
Airgel is being used for medical treatments such as regenerating human bone .
