PAb03 スメクティックA-ネマティック相転移点近傍での粘性と電気粘性効果

抄録

Rheological properties and effects of an electric field on the rheology, electrorheological= ER effects, are measured near the smectic A (SmA) - nemafic (Ne) phase transition point (T_<AN>) of 8CB (4-n-octyl-4'-cyanobiphenyl) and 8OCB (4-n-octyloxy-4'-cyanobiphenyl). With increase in temperature, the viscosity of the SmA phase decreases largely, followed by a change of the slope at T_<AN>. In the vicinity of T_<AN>, the application of the electric field induces an increase of the viscosity; with increasing the electric field strength the shear stress increases at low field and has a maximum, which is followed by a decrease to a constant value at higher fields. These properties are discussed on the basis of the field-induced orientational changes of the smectic layer and the director.