Rheology and topological defects in dissipative structures in liquid crystals

实验研究了电流体动力学对流（EHC）作用下双相液晶的表观粘度。当诱导EHC时，表观粘度随外加电压的增大先增大后减小。在第二类湍流状态下，出现许多拓扑缺陷时，粘度的峰值电压与相变电压无关，粘度的降低发生在第二类湍流状态。采用Ericksen-Leslie理论，推测剪切场产生的湍流态的各向异性使得与电场相关的剪切应力为负，从而降低了液晶的表观粘度。

The apparent viscosity of nematic liquid crystals under the electro-hydrodynamic convection(EHC) has been investigated experimentally. When the EHC is induced, the apparent viscosity increases and then decreases as the increase of applied voltage. The peak voltage of viscosity does not depend on the transition voltage at which many topological defects appear and the decrease of viscosity happens in the second type of turbulent state. By adopting the Ericksen-Leslie theory, it is speculated that the anisotropy of turbulent state created by the shear field makes the shear stress relevant to the electric field negative, which reduces the apparent viscosity of the liquid crystal.