Recent advances in vacuum assisted self-assembly of cellulose nanocrystals

Cellulose nanocrystals (CNC) iridescent films composed of the chiral nematic liquid crystal phase have attracted much attention owing to their fascinating optical properties. Herein, we summarized and discussed the recent advances in preparing iridescent CNC film via vacuum-assisted self-assembly (VASA) method, which has the advantage to fabricate large area, highly oriented and structurally homogeneous CNC liquid crystal film. The discussed aspects include (i) Factors that influence the self-assembly behavior of CNC nanorods during VASA. (ii) The strategy for modifying the optical, thermal as well as the mechanical properties of VASA assisted CNC iridescent film. (iii) Co-assembling of CNC liquid crystal phase and other functional nanoparticles by VASA technique. In all cases, key issues are highlighted and future developments that we consider as the most relevant are identified. Furthermore, future research activities are suggested in the conclusion.