Abstract

The formation of flexoelectric domains in a mixture of nematic liquid crystals N-(4-Methoxybenzylidene)-4-butylaniline and 4-Cyano-4'-pentylbiphenyl with the permittivity anisotropy ε_a ≈ 0 under dc voltage has been investigated. The threshold characteristics of the domain structure (threshold voltage and spatial period) in this mixture have been measured. The difference in the flexoelectric coefficients |e₁ – e₃| is estimated. It is shown that the threshold voltage in the mixture of nematic liquid crystals with ε_a ≈ 0 is determined only by the ratio k/(e₁ – e₃), where k is the average elasticity constant. This fact makes it possible to calculate directly the difference in the flexoelectric coefficients |e₁ – e₃|, excluding surface properties. The proposed and approved method for determining the flexoelectric coefficients can be useful for new synthesized nematic liquid crystals with ε_a < –0.5.

中文翻译：

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向列元二元混合物中的柔电畴

摘要

研究_了在直流电压下介电常数各向异性为εa≈0的向列型液晶N-（4-甲氧基苄叉基）-4-丁基苯胺和4-氰基-4'-戊基联苯的混合物中的柔性电畴的形成。已经测量了该混合物中畴结构的阈值特性（阈值电压和空间周期）。柔电系数的差异| e ₁ – e ₃ | 估计。结果表明，与ε向列型液晶的混合物的阈值电压_一≈0仅由比确定ķ /（ë ₁ - ë ₃），其中，ķ是平均弹性常数。该事实使得可以直接计算出柔电系数的差|。e ₁ – e ₃ |，不包括表面特性。用于确定挠曲电系数所提出和认可的方法可以是用于与ε新合成的向列型液晶有用_一个<-0.5。