Aerogel fibers are a new type of functional apparel fibers, featuring excellent thermal insulation, moisture absorption, and breathability. Aerogel fibers, as the name suggests, refer to the textile and apparel fiber materials made from aerogel. As is well known, gel is an elastic solid formed by the spatial network structure of colloidal particles in a dispersing medium. When the dispersing medium is water, it is called a hydrogel; while when the dispersing medium is gas, it is called an aerogel. 
Aerogel is currently the solid material with the smallest density known in the world. Due to the fact that the majority of its internal components are gases, it appears in a fog-like form, hence aerogel is also called "solid smoke". The birth of aerogel originated from the imagination of scientists who wanted to replace the water in jelly (hydrogel) with gases. 
The currently available aerogel fibers on the market are produced by grinding silica aerogel into ultrafine powder and then combining it with polyester to create a new type of functional textile fiber. Similarly, when silicon-based aerogel powder is combined with polyester, the resulting product is polyester aerogel fiber; when aerogel powder is combined with cellulose, the resulting fiber is cellulose aerogel fiber. 
Air is the best insulating and heat-preserving material. For instance, the loftiness of down feathers is an important criterion for evaluating its quality. In aerogels, over 90% of the material is air. Therefore, aerogel fibers have extremely high insulation performance. According to relevant experimental data, the insulation value of polyester aerogel fibers far exceeds the national standard with an extremely low thermal conductivity: ≤ 0.02 W/(MK). 
Meanwhile, aerogel fibers also have the characteristic of being lightweight. Since the density of aerogel is very low, ranging from 10 to 30 kilograms per cubic meter, the aerogel yarn is actually very light. Compared to ordinary textile fibers, its thickness is only half of that of ordinary fibers, and its density is as low as 0.003 grams per square centimeter. 
In addition, the aerogel fibers are filled with nanoscale gas clusters. The specific surface area of these fibers is much larger than that of porous hollow ultrafine fibers. They have good moisture absorption and ventilation properties, and are also convenient for the later dyeing and other processes in the downstream of the industrial chain.