Flow induced surface switching in a bistable nematic device

A surprising feature of liquid crystals is that rapid changes in alignment in these anisotropic liquids can induce significant flow, termed backflow, which in turn influences the alignment. A recent paper has suggested that such backflow may be the mechanism behind the fast switching observed in certain bistable nematic cells on the application of electric fields. In these experiments a weakly chiral nematic with unequal monostable surface anchorings is switched rapidly between a uniform and a -twist configuration, and it is conjectured that the backflow induced initially at the more strongly anchored surface plays a crucial role in the switching process. In this paper continuum theory is employed for nematic liquid crystals to investigate this phenomenon, and confirms that backflow can play an important role in the switching.