Electro-responsive Liquid Crystalline Nanocelluloses with Reversible Switching.

Liquid crystalline cellulose nanocrystals (CNCs) which can change their structural and optical properties in an electric field could be a new choice for advanced optoelectronic devices. Unfortunately, the exploration of its performance in an electric field is underdeveloped. Hence, we reveal some interesting dielectric coupling activities of liquid crystalline CNC in an electric field. The CNC tactoid is shown to orient its helix axis normal to the electric field direction. Then, as a function of the electric field strength and frequency, the tactoid can be stretched along with a pitch increase, with a deformation mechanism significantly differing at varied frequencies, and finally untwists the helix axis to form a nematic structure upon increasing the electric field strength. Moreover, a straightforward method to visualize the electric field is demonstrated, by combining the CNC uniform lying helix textures with polarized optical microscopy. We envision these understandings could facilitate the development of liquid crystalline CNC in the design of electro-optical devices.