Flexoelectric and dielectric effects in uniform lying helix cholesteric liquid crystals

ABSTRACT

Both flexoelectric effect and dielectric effect affect the director of uniform lying helix (ULH) cholesteric liquid crystals (CLCs). By using a finite-difference iterative method to solve the numerical solution of the Euler equations, we investigate the polar angle and the tilt angle of the director affected by the coupling of flexoelectric effect and dielectric effect. We find that flexoelectric effect and dielectric effect can be quantitatively analysed, and dielectric effect makes the director changes nonuniformly in the helix plane and inclines unevenly with respect to the helix plane. We conclude that the tilt angle is not affected by the dielectric effect under one-constant approximation. In nonequal elastic constants, the influence of dielectric effect on tilt angle is different. Under the same electric field and dielectric anisotropy, the decrease of K₃₃ or K₂₂ can increase the title angle, and K₃₃ has more influence on the title angle than K₂₂. Remarkably, our method provides a more accurate theory basis for the rotation of the optic axis in ULH CLCs.

KEYWORDS:

• Uniform lying helix
• cholesteric liquid crystals
• flexoelectric effect
• dielectric effect
• director

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Research Project of Hebei Education Department of China [grant number QN2015260], National Science Foundation of Hebei province of China [grant number A2017202004], and National Natural Science Foundation of China [grant number 11504080].