Abstract

We extend further the theoretical and experimental studies of the actual surface anchoring potential restoration by polarization microscope technique in a wedge-shaped cell with weak surface anchoring forces filled by a chiral nematic liquid crystal (in Grandjean-Cano Wedge). To realize the theoretically predicted options of observation of large director deviation angles from the easy axes the experimental studies of director distribution in Grandjean-Cano zones were performed for differing easy axes orientations at the wedge surfaces. A weak surface anchoring at one wedge surface was obtained by a photo-alignment technique. A strong surface anchoring at the second wedge surface was also obtained by a photo-alignment technique with an enlarged irradiation dose. There were observed walls with weak jumps of the director orientation between first neighboring Grandjean-Cano zones. Some experimentally obtained polarization microscope images demonstrate partially unwound director structures in zero Grandjean-Cano zone. To ensure optimal parameters of the further experiments on the actual surface anchoring potential restoration theoretical calculations of the director distribution in individual Grandjean-Cano zones were performed for various model surface anchoring potentials. It was found that especially promising for description of the experimentally found director distribution is the D-potential. As a result of the present studies the angular range of a model-independent actual azimuthal surface anchoring potential restoration was enlarge (up to π/3) and the ways of an actual surface anchoring potential restoration in a whole angular range of its determination are discussed.

摘要

我们进一步扩展了通过极化显微镜技术在手征性向列液晶填充的表面锚固力弱的楔形细胞中修复表面锚固电位的理论和实验研究（在Grandjean-Cano Wedge中）。为了实现从易轴上观察大指向矢偏离角的理论预测选项，针对楔形面上不同的易轴取向进行了Grandjean-Cano带中的指向矢分布的实验研究。通过光对准技术获得了锚定在一个楔形表面上的弱表面。还通过光对准技术以增大的照射剂量获得了在第二楔形表面上的牢固的表面锚固。在第一个相邻的Grandjean-Cano区之间，观察到的墙的指向矢方向跳弱。一些通过实验获得的偏振显微镜图像显示了零Grandjean-Cano区域中未解绕的指向矢结构。为了确保在实际表面锚固潜力恢复中进一步实验的最佳参数，针对各种模型表面锚固潜力，对各个Grandjean-Cano区域的导向器分布进行了理论计算。已经发现，对于描述实验发现的指向矢分布特别有希望的是D-电位。