糖心原创

Dr. Wim Thielemans and his research group have developed a benign method to produce cellulose based aerogels that can be easily scaled up. This production method, published recently in the journal Green Chemistry, is based on the self-assembly of cellulose nanowhiskers in water using sonication. Subsequent solvent exchange with ethanol and supercritical CO₂ drying leads to high surface area, low density materials. The cellulose nanowhiskers are long rigid rods obtained from acid hydrolysis of native cellulose fibres.  

Aerogels are highly porous materials (more than 90%) which exhibit unusual properties, such as high surface area, low density, and very good insulation properties. They can be produced from silica, alumina, tin oxide, chromia and carbon, with silica the most widely used. The unique properties associated with aerogels have lead to their use in a wide range of applications such as catalysts, catalyst supports, thermal and sound insulators,electronics, particle filters, in space and particle research and as a storage media for gases in fuel cells. More recently, cellulose has gained interest as a source material for the production of renewable and biodegradable aerogels.

Currently, the largest commercial application of aerogels is their use as high performance insulation materials, as they display heat conductivities 2-10 times lower than common polyurethane and glass wool insulation materials. However, their cost, use of toxic precursors and centralised production (leading to the shipping of large volumes of air-rich materials) makes their wider take up problematic.