The wonder gel - AEROGEL.

The Sunday Metallurgist:

Hello friends. I am Aditya, a graduate in Metallurgy and Material Technology. I blog here to kindle the spirit of Science, Enquiry and the spirit of appreciation for the latest technical and scientific advances in Materials Science and Metallurgy.

Free as I am on Sunday, I wish to devote some time to dissipate the knowledge of the various wonderful advances in Materials Science that I have come across this week.

This blog is intended to inspire young metallurgists, educate and keep veterans and busy industrial practitioners informed about the Gen X discoveries in Metallurgy and Materials Science.

Edition 1:

This week we shall dwell on Aerogel:

Ever wondered about the existence of materials with 99.9% porosity? That is transparent to light, can bare load up to 1000 times its weight, completely insulating Heat and Cold alike, and ultra light?

Yes. This material has as-many as 15 Guinness. The material is Aerogel. Aerogels are a diverse class of amazing materials with properties unlike anything else. Transparent superinsulating silica aerogels exhibit the lowest thermal conductivity of any solid known.

Dr. Samuel Stephens Kistler made aerogels for the first time. A wide description of his experimental set up can be had here. It was such a strange invention that no body believed in it first!

Today aerogels are available in all kinds of varieties. Silica Aerogel, Metallic oxide Aerogel, organic and carbon Aerogel etc.

this is how an aerosol looks...like a crystal, lighter yet than any other material that you might have handled

What amazes most are its out standing properties:

Aerogels are good thermal insulators because they almost nullify the three methods of heat transfer (convection, conduction, and radiation). They are good conductive insulators because they are composed almost entirely from a gas, and gases are very poor heat conductors. Silica aerogel is especially good because silica is also a poor conductor of heat (a metallic aerogel, on the other hand, would be less effective). They are good convective inhibitors because air cannot circulate through the lattice. Carbon aerogel is a good radiative insulator because carbon absorbs the infrared radiation that transfers heat at standard temperatures.

Due to its hygroscopic nature, aerogel feels dry and acts as a strong desiccant. Persons handling aerogel for extended periods should wear gloves to prevent the appearance of dry brittle spots on their skin.

The slight color it does have is due to Rayleigh scattering of the shorter wavelengths of visible light by the nanosized dendritic structure. This causes it to appear smoky blue against dark backgrounds and yellowish against bright backgrounds.

Aerogels by themselves are hydrophilic, but chemical treatment can make them hydrophobic. If they absorb moisture they usually suffer a structural change, such as contraction, and deteriorate, but degradation can be prevented by making them hydrophobic. Aerogels with hydrophobic interiors are less susceptible to degradation than aerogels with only an outer hydrophobic layer, even if a crack penetrates the surface. Hydrophobic treatment facilitates processing because it allows the use of a water jet cutter.

Uses:

There are many engineering applications of the wonder material. Chief of them is heat light weight heat insulations. More can be had here.

This is just a pointer. If this article enthuses you, keep looking for it, you will learn a lot. keep learning. that is the secret of being youthful - atleast at heart.

Have a nice weekend.

The Sunday Metallurgist.

How do you like it? Your comments are welcome to improve this section.

References:

Googel, aerosol.org and wiki.