Electro-rotation and electro-translation of colloidal particles in liquid crystals
,Ivan I. Smalyukh
,Oleg D. Lavrentovich
,Jack R. Kelly
Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA
Liquid Crystal Institute, Kent State University, Kent, OH 44242
We present the first observations of DC electric-field-induced rotational and translational motion of finite particles in liquid crystals. We show that the electro-rotation is essentially identical to the well - known Quincke rotation, which in liquid crystals triggers an additional translational motion at higher fields. In the smectic phase the translational motion is confined to the two-dimensional geometry of smectic layers, in contrast to the isotropic and nematic phases, where the particles can move in all three dimensions. We demonstrate that by proper analysis of the electro-rotation one can determine the in plane viscosity of smectic liquid crystals. This method needs only a small amount of material, does not require uniform alignment over large areas, and allows one to probe rheological properties locally.