Monoliths and Fibrous Cellulose Aerogels

Abstract

Cellulose aerogels can be produced by using several methods, yielding materials with extremely low densities. Their structure can be described as a type of nanofelt, which means that the elementary fibrils of cellulose are arranged in a random three-dimensional (3D) network. Aerogels made either by freeze or supercritical drying of dissolved cellulose nanofibrils can be transformed into filaments, establishing the first open porous filament for possible textile applications. They can also be converted to carbon aerogel monoliths and filaments opening up new fields of application. The review describes the different methods developed by several research groups worldwide to produce low density cellulose monoliths and filaments. It presents the microstructures obtained with various methods and the properties of cellulose aerogels.