Aerogel, a magical material known as "solid smoke" or "frozen smoke", has set off waves in the field of materials science with its unique structure and excellent performance since it was prepared by Samuel Stephens Kistler of the University of the Pacific in California, USA using supercritical drying technology in 1931. It is a typical nanoporous material with a pore size ranging from 1 to 100nm and a porosity of up to 80% to 99.8%. It is mostly translucent and extremely light. It is currently one of the lightest solids in the world.
       From the perspective of preparation technology, the birth of aerogels requires two key steps: wet gel preparation and drying. The sol-gel method is often used to prepare wet gels. The precursor, surfactant, and catalyst are dispersed in a solvent, and a sol is formed through hydrolysis and polycondensation reactions, which is then converted into a wet gel with a specific spatial structure. As for the drying process, supercritical drying, subcritical drying, atmospheric pressure drying, and freeze drying are available. Considering the equipment cost, atmospheric pressure drying is more commonly used.
       Aerogels have a wide range of applications. In terms of thermal insulation, its heat transfer coefficient is much lower than that of still air, making it an ideal material for making thermal insulation clothing, thermal insulation felt, and heat-resistant tiles. In the field of chemical environmental protection, with its large specific surface area and porous structure, aerogel can efficiently adsorb pollutants in water and help sewage treatment. In the field of new energy, aerogel can be used for hydrogen storage, providing a new way to solve the problem of hydrogen energy storage.
       In space science research, it is used to capture high-speed particles in space and help explore the mysteries of the universe. In the food industry, aerogel can be used for food packaging and storage to extend the shelf life of food. In the agricultural field, it can adsorb and destroy the lipid layer of insects to protect food from pests. With the continuous advancement of science and technology, aerogel is gradually moving from the laboratory to a broader market.
       Whether in improving the quality of life or promoting the development of cutting-edge science and technology, aerogel has shown great potential. In the future, it will surely shine in more fields and continue to rewrite the map of material applications.