What is aerogel
Aerogel is a special gel that replaces the liquid in the gel with gas without essentially changing the network structure or volume of the gel itself. one of the solid materials. It is also sometimes called "solid smoke" or "frozen smoke" because of its translucent color and ultra-light weight. Aerogels (aerogels) and dry gels (xerogels) are not the same concept. Wet gels are aerogels obtained by supercritical drying, and dry gels are obtained by atmospheric drying. Strictly speaking, aerogels should be bulk structures, while xerogels are generally powders or granules.
Due to its cumbersome and lengthy preparation process, high price and brittleness, etc., it has not attracted the attention of the industry for a long time. It was not until the advent of supercritical drying that aerogels caught the attention of researchers. The supercritical drying method can quickly and mass produce aerogel materials with precise size, arbitrary shape and complete structure. This new material looks fragile, but it is actually very strong and durable. Aerogels of different compositions can withstand different temperatures. Common silica aerogels can be used in the range of absolute zero to 650 °C. Some types of aerogels The glue can withstand high temperature up to 1400 ℃. It is gratifying that, unlike other new materials, the industrialization level of aerogel materials in my country is almost synchronized with the world, and it shows a good trend of catching up and surpassing. The first commercial aerogel company in my country was established in 2004.
Aerogels can be divided into three categories according to their components: inorganic aerogels, organic aerogels and composite aerogels. The most typical and most studied aerogels are single-component SiO2 aerogels and carbon aerogels (organic aerogels).
Characteristics of Aerogels
1. The porosity is very high, up to 99.8%; scientists say that because it has millions of pores and wrinkles, if you take 1 cubic centimeter of aerogel apart, it will fill a football field. big place. Its tiny pores not only trap pollutants like a sponge, but also act as air pockets. The researchers believe that some forms of aerogels made of platinum could be used to accelerate hydrolysis and hydrogen production. In this way, aerogels can be used to produce hydrogen-based fuels.
2. Nano-scale holes and three-dimensional nano-framework particles;
3. High specific surface area;
4. Low density;
5. The unique structure of aerogel determines its extremely low thermal conductivity, which can be as low as 0.013W/(m·K) at room temperature, which is lower than the thermal conductivity of air.