Polymer-Dispersed Cholesteric Liquid Crystal under Homeotropic Anchoring: Electrically Induced Structures with λ1/2-Disclination

Abstract

Orientational structures of polymer-dispersed cholesteric liquid crystal under homeotropic anchoring and their transformations under the action of an electric field are studied. The switching of cholesteric droplets between different topological states are experimentally and theoretically demonstrated. Structures with λ+1/2-disclination are found and considered. These structures are formed during the transformation of a twisted toroidal configuration induced by a decrease in the electric field when a relative chiral parameter N0>6.3. The transformation of the initial structure with a bipolar distribution of the helix axis into a twisted toroidal configuration and then into a structure with λ+1/2-disclination is investigated in detail. The behavior of these structures under the influence of an external electric field, as well as the appearance of structures with λ−1/2-disclination, are studied. Obtained results are promising for the development of optical materials with programmable properties.

Morphogenesis of a chiral liquid crystalline droplet with topological reconnection and Lehmann rotation

“…An example of the macroscopic structure formed by LC has been observed in droplets composed of nematic (N), smectic, or cholesteric (Ch) phase [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Notably, the chiral LC system of the Ch droplets exhibits a wide range of structural diversity.…”

“…Notably, the chiral LC system of the Ch droplets exhibits a wide range of structural diversity. Various structures with three-dimensional helices and point, line, and loop defects are formed, depending on the droplet size, helical pitch length, elastic constants, and anchoring constants [3,[11][12][13][14][15][16][17][18][19][20]. However, even when these parameters, which are considered to determine an equilibrium state, are successfully controlled, the realised structure may not be uniquely determined in real systems.…”

“…However, even when these parameters, which are considered to determine an equilibrium state, are successfully controlled, the realised structure may not be uniquely determined in real systems. Reportedly, the internal director field in the droplet can show different states, although the experimental conditions are controlled to be identical [13,15,18,20]. One may consider that this structural discrepancy is attributed to variations in the structure formation process.…”