Preparation and modification of nanocellulose using deep eutectic solvents and their applications

The inherent recalcitrance of lignocellulosic biomass causes downstream product processing commercialization challenges. In recent years, deep eutectic solvents (DESs) have attracted extensive attention as novel green and low-cost preparation processes for cellulosic biomass treatment. This work mainly focuses on the studies of the utilization of DESs in nanocellulose preparation. A summary of the structure, type, and property of DESs, the mechanism of nanocellulose fractionation in different kinds of DESs, and influencing factors of reaction conditions are discussed. We summarize the latest treatment methods, advantages, and key findings on the effects of DESs. In this review, we wish to provide a systematic overview of the recent developments of DESs in the treatment of nanocellulose and its derivatives. We not only pay attention to the treatment of nanocellulose in DESs, but also present the recent findings of nanocellulose materials and their latest applications in various fields. The challenges and prospects of DESs implementation in the cellulosic biomass treatment also be emphasized and discussed, which would be contributed to enlarging their practical utilization and promoting green development for the preparation of varied nanomaterials in extensive fields.