Abstract
Viscosity measurement of smectic liquid crystal has been performed using a shear horizontal (SH) mode device which has two acoustic wave channels. The liquid crystal cell is mounted on one channel and the other channel is used as a reference. The upper substrate of the liquid crystal cell is a glass plate coated with polyimide which is rubbed to achieve unidirectional homogeneous alignment. The acoustic phase delay difference between two output signals propagating the channels has been measured as a function of temperature. The displacement of SH mode is perpendicular to the propagation direction. The liquid crystal used in the experiment have several phases in the measured temperature range from room temperature to isotropic phase. Two viscosity components, parallel and perpendicular to the alignment direction, have been discussed in some liquid crystalline phases.
