Facile preparation of robust and biocompatible chitin aerogels

Chitin, poly(N-acetylglucosamine), was fabricated into nanoporous aerogels by using aqueous NaOH-urea solution as solvent and ethanol as coagulant. The chitin solution showed rapid temperature-induced gelation. Subsequently, highly porous and mechanically strong chitin aerogels were prepared by gelation of chitin solution from ethanol, followed by supercritical CO2 drying. The chitin hydrogel was composed of a percolating nanofibril network of about 20 nm width. By using supercritical CO2 drying, the network structure in the hydrogel was well preserved in the aerogel. Our chitin aerogels exhibit low density (0.23-0.27 g cm(-3)), large surface area (up to 366 m(2) g(-1)), moderate thermal stability and high physical integrity up to 270 degrees C, significantly high mechanical properties, and biocompatibility. Our findings are expected to lead to potential applications of chitin aerogels and allow for the fabrication of biomaterials, heat or sound insulators, catalyst supports and many others.