On the Coexistence of the Flexo-Dielectric Walls–Flexoelectric Domains for the Nematic MBBA—A New Estimation of the Modulus of the Difference between the Flexoelectric Coefficients of Splay and Bend |e_1z − e_3x|

Abstract

The coexistence of the flexo-dielectric walls and the flexoelectric domains of Vistin'-Pikin-Bobylev has been again observed in the nematic methoxybenzylidene-parabutylaniline (MBBA). On the basis of the first observation of such coexistence by Vistin' et al. and the new theory developed by us, the modulus of the difference between the flexoelectric coefficients of splay e_1z and bend e_3x, |e_1z − e_3x|, has been estimated to be around 2 × 10⁻⁴ statC/cm. It was experimentally found that the increase of the conductivity σ of the nematic MBBA from 10⁻⁹ to 10⁻⁸ (Ω · cm)⁻¹ replaced the flexoelectric domains by electrohydrodynamic movement of the fluid. The details of this movement are illustrated for the first time.

Keywords:

• Coexistence
• estimation of flexoelectric coefficient |e_1z − e_3x|
• flexo-dielectric walls
• flexoelectric domains
• MBBA

Acknowledgments

This study was supported by project N 1506, FNI-MON, Bulgaria. The author thanks Dr. Y. G. Marinov for the graphical presentation in Figs. 7 and 8.