Aerogel

Aerogel is a low-density solid-state material, derived from a gel in which the liquid component of the gel has been replaced with gas. The result is an extremely low density solid, with several remarkable properties, most notably its’ effectiveness as a thermal insulator. It is nicknamed ‘frozen smoke’, ‘solid smoke’ or ‘blue smoke’ due to its semi-transparent nature and the way light scatters in the material; However, it feels like expanded polystyrene (Styrofoam), to the touch.

Aerogel was first created by Steven Kistler in 1931, as a result of a bet with Charles Learned, over who could replace the liquid inside a jam (jelly) jar with gas, without causing shrinkage.

Aerogels are produced by extracting the liquid component of a gel through supercritical drying. This allows the liquid to be slowly drawn off, without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation.

Aerogels are remarkable thermal insulators because they almost nullify three methods of heat transfer (convection, conduction and radiation). They are good convective inhibitors because air cannot circulate throughout the lattice.

Aerogels have remarkable thermal insulative properties, having an extremely low thermal conductivity: from 0.03 W/m·K down to 0.004 W/m·K which corresponds to R-factors of 14 to 105 for 3.5 inch thickness. For comparison, typical wall insulation is 13 for 3.5 inch thickness. Its’ melting point is 1,473 K (1,200 °C or 2,192 °F).

Silica aerogel holds 15 entries in Guinness World Records for material properties, including best insulator and lowest-density solid.

In respect of insulation, aerogels can be applied, bonded to plasterboard for mechanical fixing to the interior of the home. It is also available in blanket form.

There are a variety of tasks for which aerogels are used.

Commercially, aerogels have been used in granular form to add insulation to homes 
Transparent silica aerogel would be very suitable as a thermal insulation material for windows, significantly limiting thermal losses of buildings. 
NASA used aerogel to trap space dust particles aboard the Stardust spacecraft. The particles vaporize on impact with solids and pass through gases, but can be trapped in aerogels. NASA also used aerogel for thermal insulation of the Mars Rover and space suits. 
The US Navy is evaluating aerogel undergarments as passive thermal protection for divers.