Adjusting the pore size of nano-cellulose aerogel by heat treatment in the gel stage

How to prepare a kind of porous material with the specific pore sizes according to the actual needs is always a tough problem. In this work, it has been found that it is an easy way to prepare nano-cellulose aerogels with adjustable pore size. The nano-cellulose (CNC) obtained by acid hydrolysis of microcrystalline cellulose (MCC). The prepared nano-cellulose wet gel was heat treated in an aqueous phase. Heat provides sufficient energy for further alignment of cellulose fibrils. Nano-cellulose aerogels are prepared by solvent exchange in tert-butanol and freeze drying. Solvent exchange in tert-butanol keeps the aerogel intact in a three-dimensional network structure. The characterization results show that the uniformity of the pores and the internal structure improved as the heat-treatment temperature increased. At the same time, the specific surface area and porosity of the aerogel increased, and the shrinkage decreased. This study suggests new possibilities for controlling the pore size of cellulose aerogels.