Fabrication and characterization of nano-cellulose aerogels via supercritical CO2 drying technology

In this study, we developed a novel technique to fabricate nano-cellulose aerogels. Cellulose solution was dropped to calcium chloride solution and nano-cellulose aerogels were formed through supercritical CO2 drying. The induction of calcium chloride solution maintained the shape of gel and facilitated physical gelation process. The supercritical CO2 drying aided in preservation of the original gel network and structure. The resultant spherical nano-cellulose aerogels were characterized with respect to shrinkage, specific surface area, thermal degradation, and micro-structure. They exhibited a nano-porous network structure composed of mesopores, with a high specific surface area of up to 353 m2/g and an average pore size of 8.86 nm. They showed a weak shrinkage of 4.03%. The nano-cellulose aerogels had similar thermal degradation behaviors to microcrystalline cellulose and may have wide engineering applications.