Aerogel - The LIGHTEST MATERIAL ON EARTH!

Hi everyone! Today I would like to tell you about the lightest material on planet Earth - aerogel. As a matter of fact, there exist quite a lot of kinds of aerogel. Some of them consist of metal oxides, for instance aluminium oxides. Others can consist of carbon tubes and graphenes. By the way such an aerographene is a few times lighter than air.
As you can see this material is very fragile and it crumbled when it was transported in the package. When aerogel crumbles are put on paper sheet, it can be seen that it looks translucent and very light and it is almost invisible against a light background. Aerogel’s density is extremely small about one tenth of a gram per milliliter. The density of aerogels of higher quality can even be compared to that of air. It’s not surprising because aerogel mostly consists of air. To illustrate what aerogel’s structure is like, we can compare it to that of any other gel-like substance. For instance water ball or shampoo. Now try to imagine that all water in such a material has been substituted with air. Roughly speaking, this is what aerogel looks like from inside - small porous material filled with air or another gas. It is quite easy to make aerogel. First, regular silica gel has to be made for instance by mixing together tetraethyl orthosilicate and ammonia solutions in methanol medium. Later such a gel is washed with methanol in order to wash away all traces of water. After that it is sent to a supercritical extractor. Let the complex names not scare you because everything works as simple as a bicycle. Carbon dioxide is pumped under pressure into such an extractor after that the case of of the extractor starts to heat up. When the temperature rises, the liquid carbon dioxide passes to the supercritical state that is becomes something something between liquid and gas. In such a state it can easily wash away methanol from gel substituting it with gas. This is how aerogel forms. If silica gel is just left to dry up in air, this gel will just shrink, turning into a piece of silicon dioxide because of methanol surface tension
Technical Definition By definition,
An aerogel is an open-celled, mesoporous, solid foam that is composed of a network of interconnected nanostructures and that exhibits a porosity (non-solid volume) of no less than 50%.
What Are Aerogels Made Of? The term aerogel does not refer to a particular substance, but rather to a geometry which a substance can take on–the same way a sculpture can be made out of clay, plastic, papier-mâché, etc., aerogels can be made of a wide variety of substances, including: Silica Most of the transition metal oxides (for example, iron oxide) Most of the lanthanide and actinide metal oxides (for example, praseodymium oxide) Several main group metal oxides (for example, tin oxide) Organic polymers (such as resorcinol-formaldehyde, phenol-formaldehyde, polyacrylates, polystyrenes, polyurethanes, and epoxies) Biological polymers (such as gelatin, pectin, and agar agar) Semiconductor nanostructures (such as cadmium selenide quantum dots) Carbon Carbon nanotubes and Metals (such as copper and gold) Aerogel composites, for example aerogels reinforced with polymer coatings or aerogels embedded with magnetic nanoparticles, are also routinely prepared. Learn more about the different flavors of aerogels that exist.
What Does an Aerogel Feel Like? How Strong Are They? To the touch, an inorganic aerogel (such as a silica or metal oxide aerogel) feels something like a cross between a Styrofoam® peanut, that green floral potting foam used for potting fake flowers, and a Rice Krispie®. Unlike wet gels such as Jell-O®, inorganic aerogels are dry, rigid materials and are very lightweight. In general aerogels are pretty fragile. Inorganic aerogels are friable and and will snap when bent or, in the case of very low density aerogels, when poked, cleaving with an irregular fracture. This said, depending on their density, aerogels can usually hold a gently applied load of up to 2,000 times their weight and sometimes more. But since aerogels are so low in density, it doesn’t take much force to achieve a pressure concentration equivalent to 2,000 times the material’s weight at a given point. The amount of pressure required to crush most aerogels with your fingers is about what it would take to crush a piece of Cap’n Crunch® cereal. Organic polymer aerogels are less fragile than inorganic aerogels and are more like green potting foam in consistency in that they are squish irreversibly. Carbon aerogels, which are derived from organic aerogels, have the consistency of activated charcoal and are very much not squishy. There are several examples, however, of remarkably strong aerogels that can withstand tens of thousands of times their weight in applied force. A class of polymer-crosslinked inorganic aerogels called x-aerogels are such materials and can even be made flexible like rubber in addition to being mechanically robust (see Flavors of Aerogels). One type of x-aerogel made from vanadia (vanadium oxide) is extraordinarily strong in compression with the highest compressive strength to weight ratio of any known type of aerogel and rivals that of materials such as aerospace-grade carbon fiber composites! Regardless of composition, most types of aerogel can be made stronger simply by making them denser (between 0.1 and 0.5 g cm-3), however only at the expense of their light weight and ultralow thermal conductivity.