CHOLESTERIC DOMAIN TEXTURE
CHOLESTERIC DOMAIN TEXTURE
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DOI：
10.1080/15421407208083575
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发表时间：
1972-01-01
影响因子：
0.7
通讯作者：
KLEMAN, M
中科院分区：
文献类型：
--
作者：
CLADIS, PE;KLEMAN, M
当一个大间距胆甾体在平行玻璃板之间保持距离d时，在各向同性转变附近，就会出现典型的条纹图案。条纹之间的距离约为半pitch /2（假设d >poo），并且纹理没有可测量的光学旋转功率。它不显示如果d≤poo。假设分子位于垂直于玻璃板的平面上，并在样品内部围绕平行于玻璃板的轴均匀扭曲，我们已经解决了当切向（或各向同性）边界条件应用时的Frank方程(1)。该解决方案预测了样品表面的χ(2)偏差晶格，χ'之间的距离与半间距有关。我们发现，这种结构在偏差的1 /4 （d ~ po）范围内是不稳定的，我们认为这导致了χ分裂成λ和τ。(2)后一种结构似乎充分解释了实验观察到的胆甾畴结构的特征。当x与胆甾轴平行时，也会发生相同类型的不稳定性，并导致分裂成λ；和τ。对这种情况给出了完整的计算。
When a large pitch cholesteric is held between parallel glass plates a distance d apart, near the isotropic transition, a characteristic striped pattern appears. The distance between stripes is about the half pitchpoo/2(providing d >poo) and the texture has no measurable optical rotatory power. It does not appear ifd≤poo.Assuming that the molecules lie in planes perpendicular to the glass plates and twist uniformly in the interior of the sample about an axis parallel to the glass plates, we have solved the Frank equation(1)when tangential (or homoeotropic) boundary conditions are applied. The solution predicts a lattice of χ(2)disclinations at the surface of the sample, the distance between the χ'sbeing related to the half-pitch. We have found that this configuration is not stable within a distancepo/4 (d∼po) of the disclination and we suggest that this results in the splitting of the χ into a λ and a τ.(2)This latter configuration appears to adequately explain the experimentally observed features of the cholesteric domain texture.The same type of instability occurs when a χ is parallel to the cholesteric axis, and leads also to a splitting into a λ; and τ. A complete calculation is presented for this case.