Nano-aerogel is a kind of material composed of matrix (silica, metal oxide, etc.) and gas (accounting for more than 90%), which has the characteristics of ultra-low density, high specific surface area, excellent adsorption properties and nanoscale porous structure. Among them, the thermal insulation properties of nano aerogel have been widely concerned and applied, and become one of the hot spots in the research of thermal insulation materials.

So, why does nanoaerogel insulate? In fact, the thermal insulation principle of nano aerogel can be summarized in three aspects: nanoscale porous structure, low thermal coefficient, high specific surface area and blocking thermal radiation.

1. Nanoscale porous structure

The interior of the nano aerogel is a three-dimensional network structure. This structure is filled with nanoscale pores that make it difficult for gas molecules to flow through them, greatly reducing the efficiency of heat transfer. In addition, the porous structure of the nanoaerogel also increases the thermal resistance, further preventing the transfer of heat.

2, low thermal conductivity

The pore structure of the nanoaerogel is filled with gas, which is difficult to flow because of the small pores. When heat is transferred to the nanoaerogel, the heat transfer rate is slowed down. Compared to solid materials, the thermal conductivity of gases is much lower, usually less than or equal to 0.020 W/m·K. Therefore, nano aerogel has better thermal insulation performance.

3, high specific surface area and block thermal radiation

The specific surface area of the nanoaerogel is very large, which means that it is able to interact better with other materials, increasing thermal resistance. At the same time, the pores inside the nano aerogel are very small, much smaller than the wavelength of thermal radiation, so it can effectively scatter and absorb thermal radiation and reduce thermal radiation transmission.

The reason why nano aerogel can achieve excellent thermal insulation performance is mainly due to its nanoscale porous structure, low thermal conductivity, high specific surface area and thermal radiation shielding characteristics.