Airgel is obtained by converting the solution precursor into a highly cross-linked gel network through the sol-gel process and removing the solution components in the gel by supercritical drying or freeze-drying to keep the original structure unchanged Porous, high specific surface area, low thermal conductivity with nanoscale three-dimensional continuous network, the lightest class of solid materials. For example: organic aerogels, inorganic aerogels, carbon aerogels and metal oxide aerogels. As early as 1931, Samuel Stephens Kistler of Stanford University and others prepared the first silica aerogel. Over the years, after breakthrough exploration by many researchers, molecular-based precursors were synthesized from inorganic (for example, metal Oxides, carbides) are extended to organic (for example, polymers , cellulose) and carbon (for example, carbon nanotubes, graphene) materials, and the preparation methods of aerogels are also gradually enriched and improved. It is developing in the direction of lighter density, finer particles and more . Due to the various characteristics of airgel, airgel has good application potential in materials in the 21st century. It is considered to be a bridge between the nanometer and the macroscopic world, in aerospace, sensing, heat insulation/sound, filtration / adsorption and other fields have broad application prospects.
However, most of the current airgel synthesis is based on the sol-gel conversion process, and the obtained airgel materials are in the form of macroscopic blocks. Although designed through different processes, -. series of airgel micropowder, airgel felt, airgel film and fiber have been reported one after another. However, due to the limitation of sol-gel conversion in the airgel synthesis process and the poor mechanical properties of the subsequent airgel fibers and other materials, the deep processing is limited, so that airgel fabrics The direct molding synthesis of can't do what one wishes, also has not been reported. Such a limitation makes airgel materials less competitive when faced with new diversified applications.
