Cellulose nanocrystalline film as well as preparation method and application thereof

The invention discloses a cellulose nanocrystalline film as well as a preparation method and application thereof. The preparation method of the cellulose nanocrystalline film comprises the following steps: carrying out surface modification on cellulose nanocrystalline by adopting an ultraviolet light polymerizable monomer; then mixing with nematic liquid crystal and a first solvent to prepare slurry, and preparing a film through drying evaporation induced self-assembly; and then carrying out ultraviolet light polymerization reaction treatment on the film. By adding the nematic liquid crystal and utilizing a liquid crystal template method, the cellulose nanocrystals can be uniformly oriented in the self-assembly process through the interaction between the nematic liquid crystal and the cellulose nanocrystal particles, and large-area uniform orientation can be realized under the condition that external driving is not needed; and the cellulose nanocrystalline film with uniform orientation and uniform color is ob