Abstract: Liquid crystal is a special phase state with partially ordered arrangement, and shows remarkable difference between completely ordered solid state and completely disordered liquid state. As the representative liquid crystal, cellulose nanocrystal (CNC) is currently prepared by the strong acid hydrolysis of natural cellulose, including wood, bamboo, cotton, tunicate, bacteria and so on. The individual CNC is randomly dispersed in the CNC suspension at low concentration solution. With the concentration increased, the randomly dispersed CNCs spontaneously arrange to form cholesteric liquid crystals. Due to the special optical properties such as bragg reflection, polarized light dichroism and rotary polarization, cholesteric liquid crystals from CNCs can be applied as anti-counterfeiting optical information storage, intelligent windows and liquid crystal display. In this paper, the preparation and regulation method of cholesteric liquid crystals from CNCs are introduced. The preparation and comparison of different CNCs from a large variety of resources are proposed. The regulation effects of physical factors (ultrasonic, temperature, vacuum drying and magnetic field and other regulatory factors) and chemical factors (electrolyte and additives and other regulatory factors) on the pitch of cholesteric liquid crystals from CNCs are be discussed in order to make a theoretical contribution to the regulation preparation of cholesteric liquid crystal. In addition, the formation mechanism, the structure and optical properties of cholesteric liquid crystals from CNCs are introduced, and the application status in thermo-sensitive functional materials, optoelectronic functional materials and chiral mesoporous materials are summarized. The future development trends of cholesteric liquid crystals from CNCs are also discussed as the following:1) Adjusting the preparation method to obtain CNC with negative charges, rod-shape and small size distribution which are all necessary for CNC to form ideal cholesteric structure; 2) Developing less time consuming and greener preparation method of cholesteric liquid instead of slow evaporation self-assembly method; 3) Establishing the relevant regulatory model to achieve controllable preparation of cholesteric liquid crystals from CNC; 4) Copying stable chiral nematic structure from CNCs and developing high performance multi-functional materials in the future.

Key words: cellulose nanocrystal(CNC), cholesteric liquid crystal, pitch control, functional applications