Biaxial surface potential effects in polymer-stabilized ferroelectric liquid crystal cells

Abstract

The interplay between volume and surface effects in polymer-stabilized ferroelectric liquid crystals often results in the so-called "quasi-bookshelf " or tilted layer structure. Universal description of director (the most probable orientation of long molecular axes and the optical axis) distribution within ferroelectric liquid crystal cell, stabilized by polymer network implies consideration of the confined volume effects. The discussed model of polymer-stabilized ferroelectric liquid crystal cell was investigated in terms of the continuum elastic theory with anisotropic surface effects, which also account the most probable orientation of short molecular axes. Promising applications of the biaxial surface potential for fabrication of electro-optic cells with the desired surface parameters have motivated us to embark upon the proposed model. Our model also accounts splay deformation of the spontaneous polarization. This enables us to calculate the applied voltage by the electric field and vice versa. The effect of polymer stabilization on the director orientation profiles across the cell was examined. We have found that the director-polymer network interaction coefficient yields insignificant difference between the director orientation profiles in the smectic C* (SmC*) phase of ferroelectric liquid crystal. We believe that this theoretical model can be useful for fabrication of experimental cells because the issues, which follow from the biaxial surface potential allow to control bi-and monostability of surface-stabilized ferroelectric liquid crystal cells, domain structures in electro-optical cells and the planar alignment quality.