Flow Patterns and Molecular Alignment in a Nematic Liquid Crystal due to Electric Fields

Abstract

A mechanism exists for producing molecular alignment in liquid crystals which is associated with ionic conduction anisotropy and hydrodynamic flow. This flow can be investigated with the help of either dyes, dust particles, or scattered light. Previous work on MBBA, which employed magnetic fields up to 6 kG, showed that flow cells usually extended from one electrode to the other and exhibited a domain width dependent on the strengths of the applied electric and magnetic fields. This work has been extended to include magnetic fields up to 16 kG. The thickness of the samples were 0.2 cm and 100 microns. The effect of the dielectric anisotropy on the flow cell width has also been investigated. Data which relates the flow cell width to the average state of alignment will also be presented.