Aerogel is a porous solid material. Due to its translucent color and extremely light weight, it is called "solid smoke" or "frozen smoke". Aerogel is the most porous material known to humanity, with 95% of its volume being air. It is extremely lightweight, with a density of approximately 0.1 grams per cubic centimeter. 
Initially, aerogel is a moist form of silica gel, similar to jelly. Its composition consists of water and silicon dioxide. It needs to be dried to form a solid, porous material. However, removing water molecules without disrupting the delicate structure of the silica is a lengthy, difficult and costly process. 
Now, a research team from Newcastle University in the UK has significantly reduced the cost of manufacturing aerogels by mimicking the process of how dragonflies dry their wings. 
The wings of a dragonfly are a kind of ultra-light, porous aerogel. During the larval stage of a dragonfly, it spends its time underwater. From the larva to the adult, its form and physiology undergo a transformation. This process lasts from 20 minutes to several hours. When the dragonfly emerges from its larval exoskeleton, its wings are like jelly, but within a short period of time, they will become fluffy and hard, and become completely dry. 
To achieve this, the body of the dragonfly produces sodium bicarbonate and potassium bicarbonate molecules. The bicarbonate salts decompose under the sun's rays, releasing carbon dioxide gas. This gas remains on the jelly-like wings, making them fluffy, drying them out, and finally leaving behind a dry, light and sturdy structure. Scientists have imitated this process. They added a solution of bicarbonate salts to the silica gel. After a slight heating, the bicarbonate salts decomposed into carbonate, water and carbon dioxide gas. The carbon dioxide gas was trapped in the gel, the water gradually evaporated, and the carbonate remained in the "framework" of the aerogel, becoming a solid component of it. This new technology has reduced the production cost of aerogel from around $100 per kilogram to $4 per kilogram. 
(The Mystery of Science) Issue 25, 2024