Flexoelectric effects on escaped twisted configurations of nematic liquid crystal 5CB with chiral dopants in a cylindrical cavity.

In a cylindrical cavity with a degenerate planar anchoring, the lyotropic chromonic nematic liquid crystals without intrinsic chirality tend to exhibit an escaped twisted configuration for the large saddle-splay-to-twist elastic modulus ratio, which is not found in most thermotropic liquid crystals. In this work, we consider thermotropic nematic liquid crystal 5CB with a chiral dopant confined in a cylindrical cavity with a degenerate planar anchoring. Based on the elastic theory of liquid crystal and the variation method, Euler equation and boundary conditions are obtained. The numerical results show that the director of 5CB forms an escaped twisted configuration, and the twist angle is influenced by the chiral parameter and the saddle-splay elastic constant. Under an axial electric field, the dielectric effect and the flexoelectric effect affect the LC director distribution. The single flexoelectric coefficient e1 has a large radial orientation effect on the director. The results provide a clearer understanding of the director configuration in the cylindrical cavity under the electric field and a theoretical basis for the measurement of the flexoelectric coefficients. [ABSTRACT FROM AUTHOR]