Self-assembly of low-molecular-weight cellulose into nanostructured macroscopic materials

Abstract Nanocelluloses, which are prepared from natural cellulose sources in a top-down manner through physical and/or chemical treatments, are broadening the scope of applications of sustainable biopolymers. These naturally derived nanocelluloses exhibit one-dimensional nanomorphologies, such as nanofibers and nanorods, which originate from the intrinsic nanostructures formed by cellulose molecules in plants and other cellulose-producing organisms. Recent studies have developed artificial nanocelluloses that are constructed in vitro at the molecular level via the self-assembly of low-molecular-weight (LMW) cellulose. These artificial nanocelluloses feature unique nanostructures, including rectangular nanosheets, square nanosheets, distorted nanosheets, and helical nanorods. Nevertheless, most artificial nanocelluloses reported to date are particulates. We have developed two types of nanostructured macroscopic materials through the self-assembly of LMW cellulose: nanoribbon network hydrogels and nanospiked microfibrous materials. These novel nanostructured cellulose materials have shown great promise for distinctive applications of cellulose. This Focus Review summarizes our work along with related studies on nanostructured macroscopic materials constructed via the self-assembly of LMW cellulose.