Construction and Nanostructure of Chitosan/Nanocellulose Hybrid Aerogels

Abstract

Biomass aerogels have received extensive attention due to their unique natural characteristics. However, biomass-based chitosan aerogels are often confronted with the traditional issue concerning a weak skeleton structure, namely, the corresponding huge shrinkage for chitosan aerogels in the stage from the final gel to the aerogel. Herein, we put forward a new approach to enhance chitosan aerogels by introducing natural biomaterial cellulose nanocrystal (CNC). CNC is applied to connect/cross-link chitosan chains to form its networking construction through supramolecular interaction/physical entanglement, eventually realizing the enhancement of the chitosan aerogel network structure. Chitosan aerogels modified with CNC exhibit a high specific surface area of 578.43 cm2 g–1, and the pore size distribution is in the range of 20–60 nm, which is smaller than the mean free path of gas molecules (69 nm), triggering a “no convection” effect. Hence, the gaseous heat transfer of chitosan aerogel is effectively suppressed. Chitosan aerogels with the addition of CNC show an excellent thermal insulation property (0.0272 W m-1 K-1 at ambient condition) and an enhanced compressive strength (0.13 MPa at a strain of 3%). This improvement method of chitosan aerogel in enhancing the skeleton structure aspect provides a new kind of idea for strengthening the nanoscale morphology structure of biomass aerogels.

Drug loaded cellulose–chitosan aerogel microfibers for wound dressing applications

“…The average pore width diameter of the aerogel fibers is in the range of 9-12 nm. These results imply "no convection" effect since aerogel fibers' pore sizes are typically smaller than the mean free path of gas molecules (69 nm), making them interesting thermal insulation material (Zhang et al 2021). Finally, the values of textural properties of aerogel microfiber samples is presented in Table 2.…”

Natural polysaccharide-based aerogels and their applications in oil–water separations: a review

“…The biggest challenge for chitosan aerogel is solving the problem of large shrinkage from the gel to the aerogel. 41,42 At present, researchers have continued to modify the functional groups of chitosan, such as grafting reaction, 43 monomethyl modification, 41 and other chemical methods to improve its physical and chemical properties and modifying the original functional properties of chitosan, then providing a variety of application space for the chitosan aerogel such as catalysis, 44 oily wastewater treatments, 45 and medical applications. 46 So far, some progress has been made in the research on chitosan-based aerogels in the field of oil–water separation.…”

Recent Progress in Modification Strategies of Nanocellulose-Based Aerogels for Oil Absorption Application

“…Aerogels based on nanocellulose possess great absorption capacity, giving this biopolymer promising potential in oil absorption applications. Despite the modification of the hydrophilicity of nanocellulose aerogels and the enhancement of their underwater stability, the removal of oil absorbents is yet another challenge [ 74 ]. Nanocellulose aerogels are known to have high porosity, ultralow density and high water absorption.…”