Textures of Nematic Liquid Crystal Cylindric-Section Droplets Confined by Chemically Patterned Surfaces
Textures of Nematic Liquid Crystal Cylindric-Section Droplets Confined by Chemically Patterned Surfaces
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DOI：
10.3390/cryst11010065
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发表时间：
2021-01-01
期刊：
影响因子：
2.7
通讯作者：
Gleeson, Helen F.
中科院分区：
文献类型：
--
作者：
Bao, Peng;Paterson, Daniel A.;Gleeson, Helen F.
利用偏光显微镜研究了液晶被表面限制形成细长液滴时所采用的指向矢场。通过在用10-30 μ m宽的交替的高表面能和低表面能条纹图案化的表面上对LC进行去湿来生产样品。所获得的液滴预期采用圆柱体的纵截面的轮廓，并且如这表明的，在LC被约束在圆柱形毛细管或纤维中的情况下，观察到的指向矢场是变体。因此，当在空气界面处存在正常锚定时，观察到的织构与众所周知的逃逸径向织构（对于LC混合物E7）或平面极性织构（对于LC混合物MLC 6609）相关。更令人惊讶的是，观察到以平面或倾斜方式锚定在空气界面处的双相液晶混合物MLC 7023也给出了看起来是逃逸的径向指向矢场。作为探索使用这些系统在创建传感器的可能性，添加手性掺杂剂和添加水的基板的影响也进行了研究。
The director fields adopted by nematic liquid crystals (LCs) that are confined by the surface to form long, thin droplets are investigated using polarising optical microscopy. Samples are produced by de-wetting of the LC on a surface patterned with alternating high-surface energy and low-surface energy stripes of 10-30 mu m width. The droplets obtained are expected to adopt a profile which is that of a longitudinal section of a cylinder and, as this suggests, the director fields observed are variants in the case where the LC is constrained in a cylindrical capillary or fibre. Hence, when there is normal anchoring at the air interface, the textures observed are related to the well-known escaped radial texture (for the nematic LC mixture E7) or plane polar texture (for the LC mixture MLC6609). More surprising is the observation that the nematic LC mixture MLC7023, which is anchored in a planar or tilted manner at the air interface, also gives what appears to be an escaped radial director field. As an exploration of the possibility of using these systems in creating sensors, the effects of adding a chiral dopant and of adding water to the substrates are also investigated.