Cellulose Aerogels: Synthesis, Applications, and Prospects

Abstract

Due to its excellent performance, aerogel is considered to be an especially promising new material. Cellulose is a renewable and biodegradable natural polymer. Aerogel prepared using cellulose has the renewability, biocompatibility, and biodegradability of cellulose, while also having other advantages, such as low density, high porosity, and a large specific surface area. Thus, it can be applied for many purposes in the areas of adsorption and oil/water separation, thermal insulation, and biomedical applications, as well as many other fields. There are three types of cellulose aerogels: natural cellulose aerogels (nanocellulose aerogels and bacterial cellulose aerogels), regenerated cellulose aerogels, and aerogels made from cellulose derivatives. In this paper, more than 200 articles were reviewed to summarize the properties of these three types of cellulose aerogels, as well as the technologies used in their preparation, such as the sol-gel process and gel drying. In addition, the applications of different types of cellulose aerogels were also introduced.

Prospect of Polysaccharide-Based Materials as Advanced Food Packaging

“…Generally, the synthesis of cellulose-based aerogels are consisting of three steps: (a) dissolving the cellulose or cellulose derivatives in organic solvent, (b) sol-gel step by agglomeration of colloidal particles (in the presence of crosslinker or by changing the temperature and pH) or by a phase separation process (in the presence of coagulant) and (c) supercritical drying. Cellulose aerogels possess high mechanical strength and thermal conductivity comparable with silicon aerogels [66]. Depending on the route of crosslinking, as well as on operational drying conditions, it is possible to tailor morphological and textural properties of cellulose aerogels [66][67][68][69][70].…”

“…Cellulose aerogels possess high mechanical strength and thermal conductivity comparable with silicon aerogels [66]. Depending on the route of crosslinking, as well as on operational drying conditions, it is possible to tailor morphological and textural properties of cellulose aerogels [66][67][68][69][70]. Super water adsorbent aerogels that can be potentially used for food packaging application were obtained by regenerated cellulose [71] and cellulose nanocrystals [72].…”

Drying of cellulose nanocrystal gel beads using supercritical carbon dioxide

“…Aerogels are highly porous nanostructured materials which exhibit many unusual properties, such as high porosity and surface area, low density and low thermal and electrical conductivity. 1 Cellulose and nanocellulose aerogels have demonstrated some particular applications where biocompatibility and biodegradability are needed, such as for medicinal (medical implants and tissue engineering), cosmetic and pharmaceutical (drug delivery) applications and energy (energy/hydrogen storage devices), and their application fields (sorbents for gas and liquid, catalyst carriers, thermal insulation) are extending even more …”

“…1 Cellulose and nanocellulose aerogels have demonstrated some particular applications where biocompatibility and biodegradability are needed, such as for medicinal (medical implants and tissue engineering), cosmetic and pharmaceutical (drug delivery) applications and energy (energy/hydrogen storage devices), and their application fields (sorbents for gas and liquid, catalyst carriers, thermal insulation) are extending even more. [2][3][4][5][6] One major challenge for the preparation of aerogels is to eliminate the liquid solvent from the wet gel whilst avoiding the collapse of the already existing nanoporous structure due to the subsequent shrinkage of the dried gel. Aerogels from cellulosic materials have been prepared through freeze-drying of solutions or gels.…”

Recyclable Xanthan/TiO2 Composite Cryogels towards the Photodegradation of Cr(VI) Ions and Methylene Blue Dye

“…When the precursor gel is frozen and the solvent is removed by freeze-drying, the monoliths are classified as cryogels [2]. Aerogels and cryogels can be tailored by choosing the material and synthesis that best fit the desired application [3,4].…”