Converse Flexoelectric Effect in Bent-Core Nematic Liquid Crystals
Converse Flexoelectric Effect in Bent-Core Nematic Liquid Crystals
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DOI：
10.1021/jp903241z
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发表时间：
2009-07-09
影响因子：
3.3
通讯作者：
Petrov, A. G.
中科院分区：
文献类型：
--
作者：
Kumar, Pramoda;Marinov, Y. G.;Petrov, A. G.
我们报告了两种具有相反介电各向异性的弯芯向列液晶的逆挠曲电效应。结果基于垂直样品中面内场驱动畸变的石油电光研究（Helfrich 方法）。它们通过赫尔弗里希理论的扩展来解释，该理论考虑了高阶畸变。这两种化合物的弯曲弯曲系数与卡拉米特材料中的通常数量级不同，与之前研究的弯曲核心向列相不同，报告了弯曲弯曲系数的巨大值。为了解决这种差异，我们提出了一种具有显示四极弯曲电性的非极性簇的分子模型。该研究还包括对介电正性材料中表面极化不稳定性的测量；由此推导出的张开弹性系数也是常规量级的。
We report on the converse flexoelectric effect in two bent-core nematic liquid crystals with opposite dielectric anisotropies. The results are based oil electro-optic investigations of inplane field-driven distortions in homeotropic samples (the Helfrich method). They are interpreted by an extension of the Helfrich theory that takes into account the higher order distortions. The bend flexocoefficient for both the compounds is of the usual order of magnitude as in calamitics, unlike in a previously investigated bent-core nematic for which giant values of the bend flexocoefficient are reported, In order to resolve this discrepancy, we propose a molecular model with nonpolar Clusters showing quadrupolar flexoelectricity. The Study also includes measurements on Surface polarization instabilities in the dielectrically positive material; the splay flexocoefficient thereby deduced is also of the conventional order.