What is the most difficult solid?
The most diffuse solids are aerogels, created by the conventional gel of supercritical drying. Supercritical drying allows the liquid to be extracted from the gel without accumulating the gel matrix due to the capillary effect. Supercritical drying requires a high temperature (705 ° F, 374 ° C) and pressure (219 atmosphere). It forces the liquid to enter the state indistinguishable from the gas or liquid (supercritical liquid), then warms it up and causes it to be transformed into gas. The capillary effect is prevented by avoiding the direct transition of the liquid to the gas, as in evaporation. Airgel was invented by Steven Kistler in 1931, allegedly as part of a bet with his boyfriend to see who could extract the liquid from the jam while still retaining its volume.
Aerogels is a remarkable material. Nicknamed "frozen smoke" for its appearance is Airgel extremely scattered, made of 99.8% air. Its density is only 3 milligrams on a cubic centimeter (3 kg per cubic meter), 0.3% of water dennity. Airgel is 3780 times more distracted than lead. Silicon Airgel is listed in an incredible 15 items in the Guinness Book of Records, including the most diffuse solid and best thermal insulators. Airgel has recently been used by NASA on the StarDust Mission to capture small pieces of comet Wild 2.
Despite its low density, the aerogel is easy to handle. It intersects with 100 nanometer holes, has a huge surface area, which makes it ideal for supercapacitors. Airgel is such a fantastic thermal insulator that its thin layer can protect matches from the ficking ignition. Its high insulation abilities caused them to be designed for use in space suits and military armor.
Airgel can be made using various default materials, including silicon, oxide, chromia, tin oxide and recent carbon. Using carbon nanotubes scientists have created materialsI aerogel called carbon nanofoam, which has only 1% density of previously produced aerogels, only several times by air density. Carbon nanofoam is indeed the most dispersed solid.