Photo Alignment of Liquid Crystals by an Azo Dye Doped Reactive Mesogen Layer

Blanchard-Lapierre, Alexia; Bagramyan, Arutyun; Galstian, Tigran

doi:10.1080/15421406.2012.663521

Cited by 1 publication

(1 citation statement)

References 16 publications

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“…[21][22][23] Typically for photoalignment, a photosensitive material is coated on the substrate and treated by light to gain the surface effect that aligns LCs. [24] To realize the effect, the photosensitive material coated on the substrate needs to create an optical anisotropy by the photosensitive fragments or their photoproducts resulting from the photochemical reactions. [25,26] The anisotropic interfacial interaction between the surface layer and the LC molecules can determine the preferential orientation direction of LCs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Study of Copolymers Bearing Two Coumarin Side Groups in Monomer Unit: Toward Photoalignment of Liquid Crystals

Chen

Han

Hou

et al. 2023

Macro Chemistry & Physics

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Photodimerization of coumarin derivatives in photoactive polymers under linearly polarized UV (LPUV) light irradiation is a photochemical reaction often used to prepare the surface alignment layer that can orient liquid crystals (LCs) due to the anisotropic interfacial interactions. Herein, the synthesis of a series of novel coumarin‐containing copolymers and their use for the photoalignment surface layer of LCs is reported. These copolymers have the particular feature of bearing two coumarin side groups in each monomer unit, which is designed to have a high content of the chromophores. The alignment of LCs induced by the photoalignment layers of the coumarin‐containing copolymers is investigated. It is found that the photoalignment layers can effectively induce orientation of LC molecules along the direction of the UV light polarization used to prepare the surface layers, with an order parameter of around 0.5 achieved by adjusting the preparation conditions. Moreover, the electro‐optical behaviors of LC cells made with the photoalignment layers are investigated, confirming the alignment of LCs without the use of rubbed surfaces. Optically inscribing the photoalignment layer for nonuniform and organized LC alignment is also demonstrated.

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