*Cellulose Nanocrystals: From Classical Hydrolysis to the Use of Deep Eutectic Solvents DOI: http://dx.doi.org/10.5772/intechopen.89878*

added to intrinsic birefringence of CNC induce interesting optical properties. Moreover, when ordered CNC suspension is solvent evaporated and thus solidified in a self-standing film, conserved chiral nematic structure (helicoidal structures) and iridescent behavior of films are observed and monitored by CNC concentration and surface charge as well as suspension sonication [27, 28]. **Figure 7** shows explicit pictures of these rheological and liquid crystalline properties.

All these outstanding surface and physical properties of CNC confirm their high and increasing interest in research and industrial field during the last decades. Although their isolation and characterization are currently well-advanced and optimized, application fields are at the center of ongoing researches, as described in the following part.
