Nanoscale structures of polarisation-modulated bent-core materials in thin films
Nanoscale structures of polarisation-modulated bent-core materials in thin films
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薄膜中偏振调制弯芯材料的纳米级结构
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发表时间：
2015
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通讯作者：
A. Jákli
中科院分区：
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作者：
Cuiyu Zhang;S. M. Salili;Nicholaus Diorio;W. Weissflog;A. Jákli
我们提出了小角度X射线和低温透射电子显微镜（cryo-TEM）研究三个硝基取代（n-OPIMB-NO2，n = 7，9和16）的n-core液晶（LC），形成独特的光学图案被称为B7纹理。小角X射线散射研究表明，在a ~ 3.4-4.7 nm和bX ~ 9-16 nm之间有两个周期。约100 nm厚的膜的Cryo-TEM图像没有显示出a-周期性，而是仅显示出比通过X射线在本体中测量的bX小约1 nm的周期性bT。此外，还观察到周期c ~ 100-200 nm的强度调制。这些观察结果可以用B1型结构来解释，其中在展曲域的边界处存在半层台阶不连续性，并且其中分子在任何地方都垂直于衬底。
We present small angle X-ray and cryogenic transmission electron microscopy (cryo-TEM) studies of three nitro-substituted (n-OPIMB-NO2, n = 7, 9 and16) bent-core liquid crystals (LCs) that form peculiar optical patterns known as B7 textures. Small angle X-ray scattering studies show two periodicities between a ~ 3.4–4.7 nm and bX ~ 9–16 nm. Cryo-TEM images of about 100 nm thick films do not show the a-periodicity, but only periodicities bT that are about 1 nm smaller than bX measured in bulk by X-ray. Additionally, an intensity modulation with a period c ~ 100–200 nm is observed. These observations can be explained by a B1-type structure, where there are half-layer step discontinuities at the boundaries of the splay domains, and where the molecules are everywhere normal to the substrate.