Physical Review E
electric-fields, instability, electroconvection, cells, mbba, scattering, anisotropy, alignment, polymer, regime
The transition from surface to bulk normal dielectric rolls in a nematic liquid crystal is imaged by fluorescence confocal polarizing microscopy. The three-dimensional director structure and the liquid flow are scanned in both the layer plane and the transverse plane. Two systems of small-scale convective flow are formed, one at each electrode. Strong anchoring makes director oscillations difficult and charges accumulate by the Carr-Helfrich mechanism. The middle region is a structureless convection where the director oscillates with the frequency of the applied voltage. The small-scale flow eventually fills the cell from one electrode to the other as one system of thin and elongated rolls. The true dielectric mode is not a director pattern, rather a surface flow instability.
Gheorghiu, N.; Smalyukh, Ivan I.; Lavrentovich, Oleg; and Gleeson, Jim T. (2006). Three-Dimensional Imaging of Dielectric Patterns in Electrohydrodynamic Convection of a Nematic Liquid Crystal. Physical Review E 74(4). doi: 10.1103/PhysRevE.74.041702 Retrieved from http://digitalcommons.kent.edu/cpippubs/203