Aerogel according to the material, can be divided into inorganic aerogel and organic aerogel two categories, silica (Si02) aerogel belongs to one of the inorganic aerogel, is also the easiest to prepare and is the most widely used class.

The main components of aerogel coating include powder (Si02 aerogel powder) and emulsion composition, of which Si02 aerogel is used as an important part of the coating, which will make the coating have special functions such as heat insulation, high temperature resistance, fire prevention, adsorption, photocatalysis and sound insulation and absorption, so its quality will greatly affect the performance of the coating.

Aerogel coatings will vary according to the different formulations of fillers and auxiliaries added, which will result in the main functions of the Si02 aerogel coatings made. At present, Si02 aerogel coatings are often used in the following fields.

1. Heat insulation field
Si02 aerogel coatings can be applied in the field of thermal insulation thanks to the nanopore and three-dimensional network structure of Si02 aerogel. The unique nanoporous structure of Si02 aerogel restricts the free flow of air molecules and inhibits the convective conduction of air. The three-dimensional mesh structure forms the reflective and refracting surfaces of thermal radiation with "infinite heat shield effect", which inhibits the radiation heat conduction to the maximum extent. Therefore, the application of Si02 aerogel with excellent thermal insulation performance in thermal insulation coating will greatly improve the thermal insulation effect of the film.
Tests have proved that 1mm thick aerogel insulation coating is better than 8cm thick polystyrene foam board thermal insulation, so it is widely used in building walls, roofs and other thermal insulation, but also can be used in low temperature pipelines, storage tanks, communication base stations, ships, automobile transportation industry and other fields.

2. High temperature and fire resistance

Si02 aerogel is a non-combustible material, and has thermal insulation properties, Si02 aerogel paint applied to the surface of the substrate, can effectively prevent heat transfer, reduce the flammability of the substrate and delay or even prevent the spread of fire. Si02 aerogel coating can be used in high temperature environment above 200℃ for a long time, and maintain good porous network structure characteristics below 900℃.
Si02 aerogel coating can be used in high temperature steam pipeline, rich temperature furnace, oil cracking equipment, engine parts and metal high temperature protection and fire prevention in metallurgical industry.

3. Adsorption field
The adsorption properties of Si02 aerogel coatings are due to the three-dimensional mesh structure and high internal surface area of the aerogel. The three-dimensional network structure is easy to adsorb organic solvents and organic substances. In addition, the number of atoms in the internal surface area is large, and the nearby atoms are few, so it is very easy to adsorb other atoms. The adsorption of Si02 aerogel is better than that of activated carbon, silica gel, alumina and other common adsorbents.
Si02 aerogel coating can be widely used in air purification, sewage treatment, water vapor adsorption, medical filtration, seawater purification and other fields, and has broad application prospects.

4. Field of photocatalysis

Si02 aerogel has a porosity of up to 99.8% and a specific surface area of up to nearly 1000 m2 / g, which makes it of great interest in catalyst applications. Si02 aerogel coating can have catalytic reaction function under certain wavelength light irradiation, can decompose toxic substances, sterilization, degradation of organic matter and purify air.

5. Acoustics
There are a large number of tiny connected pores in the inside of Si02 aerogel. When sound waves enter the inside of Si02 aerogel, friction occurs in the inside constantly, and sound waves are consumed to achieve the effect of sound insulation and noise reduction. The Si02 aerogel coating is coated on the surface of other sound absorbing materials to make sound absorbing effect stronger sound insulation materials.
In practical applications, we are familiar with the Shanghai World Expo Zero carbon pavilion and Vanke laboratory building are applied aerogel coating, indicating that the aerogel coating has outstanding safety and energy saving effect.
Si02 aerogel coatings are applied in the fields of heat insulation, high temperature resistance, fire prevention, adsorption, photocatalysis and sound insulation and absorption. It is believed that with the continuous progress of science and technology, Si02 aerogel coatings will be applied in more and more fields.