Electric Field‐Driven Control of Cholesteric Cellulose Nanocrystal Orientation and Morphology

Abstract

AbstractA new insight into the control of the helix axis direction and pitch of an aqueous suspension of cellulose nanocrystal‐derived lyotropic liquid crystals by electric field strength and frequency is presented. At low frequency, liquid crystalline cellulose nanocrystals exhibit anomalous negative birefringence, with the helix axis lying parallel to the electric field, followed by a helix pitch decrease upon increasing the field strength. In contrast, they initially show a positive birefringence at high frequency, with the helix axis perpendicular to the electric field and increasing helix pitch with increasing field strength. When the electric field strength is further increased, the helix axis rotates orthogonally to align parallel to the electric field, producing negative birefringence. Such electric field‐induced manipulation of liquid crystalline cellulose nanocrystal helix axis orientation and pitch can set the stage for various fascinating soft matter nanotechnology applications.