Preparation of ambient-dried multifunctional cellulose aerogel by freeze-linking technique

Ambient drying is currently the cheapest and most efficient way to prepare aerogels, but it is invisible for the preparation of cellulose aerogels. In this paper, we describe a method of preparing cellulose aerogels that can be dried under atmospheric pressure by freeze-linking technique. The amino silane coupling agent forms an amino-rich polymer layer on the bacterial cellulose surface during the freezing process. And, the cross-linked network constructed by Schiff base reaction can strengthen the fiber skeleton in the process of solvent exchange. Due to the double cross-linked network structures, the cellulose ethanol gel can be dried directly under atmospheric pressure at 60 °C and the volume shrinkage can be as low as 3.3 %±1.4 %. In the process of solvent exchange, the loss of some polysiloxane causes defects in the aerogel, which not only reduces its thermal conductivity but also increases its specific surface area. And the water resistance, thermal performance, and dye adsorption performance of the aerogel are also significantly improved. This study provides a low-cost and high-efficiency solution for the manufacture of cellulose aerogels and promotes their wide applications.