Polar electro-optic switching in droplets of an achiral nematic liquid crystal
Polar electro-optic switching in droplets of an achiral nematic liquid crystal
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DOI：
10.1080/026782999203896
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发表时间：
1999-10
期刊：
影响因子：
2.2
通讯作者：
P. Rudquist;Eva D Korblova;D. Walba;R. Shao;N. Clark;J. Maclennan
中科院分区：
文献类型：
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作者：
P. Rudquist;Eva D Korblova;D. Walba;R. Shao;N. Clark;J. Maclennan
在与各向同性相共存的非手性向列液晶液滴中观察到极性电光响应。在交叉偏振片之间，每个薄饼状的液滴以与偏振片轴对齐的中心交叉形式显示消光刷。外加电场E诱导十字围绕电场方向旋转，大约一半的液滴顺时针切换，另一半逆时针切换。当E反转时，每个液滴的旋转感觉发生变化。我们提出了在较大的弹性常数和切向边界条件下，扭转双极定向器结构在液滴中的稳定性。分子沿着液滴的直径垂直于施加的电场扭曲，这导致了反向挠曲电效应的线性旋转。由于分子是非手性的，所以在任何液滴中，扭曲的手性以及开关的感觉都是任意的。
A polar electro-optic response is observed in droplets of an achiral nematic liquid crystal in coexistence with the isotropic phase. Between crossed polarizers each pancake-shaped droplet shows extinction brushes in the form of a centred cross aligned with the polarizer axes. An applied electric field E induces a rotation of the crosses about the field direction, with about half the droplets switching clockwise and the other half anticlockwise. The sense of rotation in each droplet changes when E is reversed. We propose that a twisted bipolar director structure is stabilized in the droplets by a relatively large splay elastic constant and tangential boundary conditions. The molecules twist along the diameter of the droplets, perpendicular to the applied field, which results in a linear rotation of the director by the inverse flexoelectric effect. Since the molecules are achiral, the handedness of the twist, and hence the sense of the switching, in any droplet is arbitrary.