High strength cellulose aerogels prepared by spatially confined synthesis of silica in bioscaffolds

Cellulose aerogels are ultra-low density materials and generally exhibit poor mechanical properties, incorporation of inorganic fillers into these structures can greatly increase their strengths and moduli. Silica/cellulose composite aerogels were prepared by in situ synthesis of silica in the porous structured cellulose hydrogel scaffolds by using water glass as silica source. The concentration of water glass solution had an obvious influence on the microstructure of the composite aerogels. The synthesized silica in the cellulose scaffold had particle-like morphology when lower concentrated water glass solution was used, and the particle size increased with the increasing of the water glass solution concentration. The spatially confined synthesized inorganic components preserved both the chemical cellulose integrity and open-porous cellulose network structure. The compressive properties of the silica/cellulose aerogels greatly exceeded those of pristine cellulose aerogels. Moreover, unlike inorganic silica aerogels, the composite aerogels had high flexibility, withstanding large amounts of compressive strain without failure.