Research On Flexoelectric Effect Of Chiral Nematic Liquid Crystal

As the helical axis of short-pitch Chiral nematic liquid is the optic axis, its Spatialorientation affects the characteristics of the light propagation in liquid crystal directly.Using the flexoelectric effect, the chiral nematic liquid crystal optical properties could bechanged by changing an electric field,which makes to open the new display modebecomes possible. This paper researched the influence of splay and bend deformation ofChiral nematic liquid crystal on helical optic axis rotation angle and response times offlexoelectric effect and the influence of the dielectric anisotropy on response times offlexoelectric effect on the free boundary conditions by the methods of theoretical analysisand numerical simulation. In considering the difference between the splay and bendelastic deformation, the system has a non-uniform density of free energy. Assumingchiral nematic liquid crystal molecules have a uniformly rotation helix axis and when thehelical axis inclinations are the same, the two states have the same molecular distribution.Using the Euler equations and equilibrium conditions, we get the mean free energydensity and the equilibrium equation of the helical axis.We got dynamics of flexoelectriceffect through the torque balance equation. The influences of the two deformationsdifferences on helix axis tilt angle and response characteristics are discussed bynumerical calculation. The results show that the difference of the two deformationsmakes both the helical axis rotation angle and the characteristic response time change andthe greater the difference the faster the change. When considering the dielectricanisotropy, it shows that the larger the dielectric constant anisotropy, the more dull ofmotion characteristics than the isotropic. The results obtained in this paper provide abasis for rapid electro-optics response.