Silica Aerogel

Silica Aerogel in Insulation is one of the best-known super-insulating materials, attracting interest for its low bulk density, high porosity, hydrophobicity, optical transparency, and mechanical strength. In aeronautical applications, it can provide thermal insulation for aircrafts, spacecraft, and planetary vehicles. It is also used for energy efficiency, fire protection, and thermal insulation in homes. It can also be used as a coating for windows and as a filler in electrical components. In addition to its insulating properties, silica aerogel is a fire-retardant and can absorb shocks and vibrations. In the military field, it can protect soldiers from heat and radiation and be used to make armored suits.

The physical properties of silica aerogel are strongly dependent on the synthesis method and chemical composition. Therefore, different methods will result in dissimilar typical values for several properties. The thermal, radiative and gaseous conductivities of silica aerogel are dependent on pore size and pressure, as well as the nanoscaled structure of the material.

It is possible to reduce the thermal conductivity of silica aerogel by increasing the pore size or decreasing the pressure. However, these changes also increase the permeability of the material and can affect the surface morphology. This makes it difficult to achieve a balance between these factors.

In order to increase the permeability and decrease the thermal conductivity of silica aerogel, a process called calcination can be employed. This process involves the heating of silica gel in air at elevated temperatures to a point where it begins to crystallize. The resulting material has a much lower thermal conductivity, but it is still more brittle than pure silica.

To make a more robust material, it is necessary to incorporate reinforcing agents such as carbon black, polyethylene, or boron into the gel. These additives can be added during the synthesis process or afterward, and they can be crosslinked to enhance the strength of the material. These additions are especially useful for applications that require strong mechanical and chemical resistance, such as abrasion and impact resistance.

Developed from space research, Aerogels have drawn attention for their extreme insulating properties, including a low bulk density and high porosity, which allows up to 95% of the material to be composed of air. They are also fire-retardant and can absorb a wide range of frequencies from gamma rays to visible light. The French start-up ENERSENS specializes in producing aerogel mats and granulates that can be used to prevent electric cars from overheating and as a thermal insulator for buildings.

The insulating properties of Aerogel can save energy in residential houses and help to reduce CO2 emissions. These benefits can be further enhanced if the material is used in the manufacture of solar panels and other renewable energy devices. It can also be used in the production of fire retardant clothing, fire protection equipment, and medical equipment. Currently, a number of companies are developing products based on silica aerogel, and the technology is becoming more affordable. However, the insulating properties of this material are not yet suitable for large-scale use in commercial applications.