Flexoelectric Polarization in a Nematic Liquid Crystal Enhanced by Dopants with Different Molecular Shape Polarities.
Flexoelectric Polarization in a Nematic Liquid Crystal Enhanced by Dopants with Different Molecular Shape Polarities.
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DOI：
10.1021/acsomega.2c00023
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发表时间：
2022-03-22
期刊：
影响因子：
4.1
通讯作者：
Komitov L
中科院分区：
文献类型：
--
作者：
Škarabot M;Mottram NJ;Kaur S;Imrie CT;Forsyth E;Storey JMD;Mazur R;Piecek W;Komitov L
由于液晶的挠曲电极化与外加电场之间的线性耦合，挠曲电性可能对双折射和双折射液晶的开关特性具有重要影响。这种耦合是胆甾类化合物在均匀的卧螺旋结构中排列的非凡电光效应的起源，导致快速切换和场控制上升和下降时间。因此，当设计和合成液晶材料和/或用适当的挠曲电化合物（掺杂剂）制备它们的混合物时，液晶的挠曲电性质已经成为重要的问题。在这里，我们报告的弯曲电极的高度极性的液晶主机通过掺杂它与两个新合成的掺杂剂SK 1-6和SK 1-8，具有曲棍球棒的分子形状，并比较其掺杂效果与二聚体掺杂剂CB 7 CB具有对称的弯曲分子形状之一。所有掺杂剂以小浓度（5wt%）溶解在掺杂基质中，使得可以应用展曲es和弯曲eb挠曲电常数之间的差（即（es-eb））对基质材料中掺杂剂浓度的依赖性的线性近似。以这种方式，曲棍球棒掺杂剂SK 1-6和SK 1-8的（es-eb）估计分别为0.182和0.204nC/m。这些掺杂剂获得的挠曲电极化是迄今为止文献中报道的最高的。
Flexoelectricity may have an important impact on the switching properties of nematic and cholesteric liquid crystals due to the linear coupling between the flexoelectric polarization of the liquid crystal and the applied electric field. This coupling is the origin of the extraordinary electro-optic effect in cholesterics aligned in the uniform lying helix texture, resulting in fast switching and field control of both rise and fall times. Therefore, the flexoelectric properties of the liquid crystals have become an important issue when designing and synthesizing liquid crystal materials and/or preparing their mixtures with appropriate flexoelectric compounds (dopants). Here, we report on the flexoelectric polarization of a highly polar nematic liquid crystal host enhanced by doping it with two newly synthesized dopants SK 1–6 and SK 1–8, possessing a hockey stick molecular shape, and comparing their doping effect with the one of the dimeric dopants CB7CB possessing a symmetric bend molecular shape. All dopants were dissolved in small concentration (5 wt %) in the nematic host so that the linear approximation of the dependence of the difference between splay es and bend eb flexoelectric constants, that is, (es – eb), on the concentration of the dopant in the host material can be applied. In this way, (es – eb) was estimated for the hockey stick dopants SK 1–6 and SK 1–8 to be 0.182 and 0.204 nC/m, respectively. The obtained flexoelectric polarization of these dopants is among the highest reported in the literature so far.
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影响因子：
2.2
作者：
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通讯作者：
Goulding, Mark
影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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