Dynamics of electro-orientation of birefringent microsheets in isotropic and nematic liquid crystals.

We study the dynamics of electric field driven multiaxis electro-orientation of birefringent microsheets in both the isotropic and nematic phases of a liquid crystal. For a fixed direction of applied field in the isotropic phase, there are two critical fields above which the microsheets show two orientations. In the nematic phase, it shows three rotations in both planar and homeotropic cells. These orientations are observed at varying voltages and wide time scales and are explained based on the competing effect of the electric, elastic, and viscous torques. The control of the orientation of anisotropic microparticles (both optically and geometrically) by transducing external energy may be useful in electro-optics and photonics.