Flat nonprofiled surface of photoalignment AtA-2 azo-dye layer possesses simultaneously low molecular orientation anisotropy and strong azimuthal anchoring energy. We explain how flat surface of alignment layer orients nematic liquid crystal and show the existence of the new photoalignment mechanism based on photo-induced hole dipole moments in the azo-dye layer. The dependence of anchoring energy coefficient on the square of dipole moments of the alignment layer and the liquid crystal layer is formulated, grounding the idea of chemical modification of AtA-2 azo-dye with molecular dipole moment ~16D to obtain novel high anchoring photoalignment material. The new AtA-0042 azo-dye with molecular dipole moment ~27.5D is synthesized and experimentally verified. Strong azimuthal anchoring energy over >1.4 × 10⁻⁴ J/m² is obtained for AtA-0042 photoalignment material layer with ~40 mJ/cm² exposure dose.

中文翻译：

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基于新型光致空穴偶极子机制的高锚定光取向材料

光取向 AtA-2 偶氮染料层的平坦非异形表面同时具有低分子取向各向异性和强大的方位角锚定能。我们解释了取向层的平坦表面如何使向列液晶取向，并展示了基于偶氮染料层中光致空穴偶极矩的新光取向机制的存在。制定了锚定能量系数对取向层和液晶层偶极矩平方的依赖关系，基于分子偶极矩~16D化学改性AtA-2偶氮染料以获得新型高锚定光取向材料的想法. 合成并实验验证了具有分子偶极矩~27.5D 的新型 AtA-0042 偶氮染料。超过 1.4 × 10 ^{-4 的}强方位角锚定能量 J/m ²是针对 AtA-0042 光致取向材料层以~40 mJ/cm ²曝光剂量获得的。