Zhang Shanju, Terentjev Eugene M, Donald Athene M
Cavendish Laboratory, University of Cambridge, Madingley Road, CB3 0HE, Cambridge, United Kingdom.
J Phys Chem B. 2005 Jul 14;109(27):13195-9. doi: 10.1021/jp051374n.
Polarizing optical microscopy is employed to study director fields around disclinations in side-chain liquid crystalline polymer films. Optical black brushes together with stripes around disclinations are observed. The stripes run parallel to the local director and thus decorate overall patterns of nematic director around disclinations. Three director patterns involving radial, spiral, and circular microstructures of a positive integer disclination with s = +1 and one hyperbolic pattern of a negative integer disclination with s = -1 are observed in the thin film. It is found that the specific configurations of a pair of (+1, -1) disclinations form during the late stage of annihilation. Increasing the film thickness leads to disclination instability. We observe that black four-brushes of disclinations with s = +/-1 split into black two-brushes, where two types of director patterns of disclinations with half-integer strengths of s = +/- 1/2 produce. Theoretical analysis is presented to explain this instability.
利用偏光光学显微镜研究侧链液晶聚合物薄膜中向错周围的指向矢场。观察到了光学黑刷以及向错周围的条纹。这些条纹与局部指向矢平行，从而修饰了向错周围向列相指向矢的整体图案。在薄膜中观察到了三种涉及正整数向错（s = +1）的径向、螺旋和圆形微结构的指向矢图案，以及一种负整数向错（s = -1）的双曲线图案。发现在湮灭后期会形成一对（+1，-1）向错的特定构型。增加薄膜厚度会导致向错不稳定。我们观察到，s = +/-1的向错的黑色四刷分裂为黑色两刷，在此过程中产生了两种具有半整数强度s = +/- 1/2的向错指向矢图案。本文进行了理论分析来解释这种不稳定性。
