Electrorotation of colloidal particles in liquid crystals.
We present the first observations of dc electric-field-induced rotational motion of finite particles in liquid crystals. We show that the electrorotation 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 a proper analysis of the electrorotation, 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 enables probing rheological properties locally.
Liao
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Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA.
Smalyukh
I I
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Kelly
J R
JR
Lavrentovich
O D
OD
Jákli
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A