Nematic Liquid Crystal Disclination Lines Driven by A Photoaligned Defect Grid. Issue 4 (22nd December 2021)

• Record Type: Journal Article
• Authors: Nys, Inge; Berteloot, Brecht; Beeckman, Jeroen; Neyts, Kristiaan
• Is Part Of: Advanced optical materials. Volume 10:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-22
• Subjects: defect grids -- disclination lines -- nematic liquid crystals -- photoalignment; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202101626
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Photoalignment for nematic liquid crystals makes it possible to design complex alignment patterns with point defects, that can act as anchoring points for disclination lines. This feature may be used to realize novel electro‐optical devices with bistability or enhanced scattering and is promising for material applications such as stimuli‐responsive actuators, active matter, and assembly of colloidal particles. However, the applicability is hampered by the limited understanding of the interaction between the defects in the photoalignment pattern and the disclination lines in the nematic liquid crystal. In this work disclination lines are studied that connect surface defects of strength 1/2 arranged in a periodic grid. The elastic tension is estimated in the disclination line and it is shown how the director configuration close to a +1/2 surface defect is influenced by the fact that the three elastic constants are different. A tilt is induced close to the surface that can be amplified and visualized by applying a voltage. Abstract : Liquid crystal alignment by polarized blue light allows to create periodic patterns at the surface with +1/2 and −1/2 defects. The defects become connected in pairs by disclination lines when cooling from the isotropic phase. Polarization microscopy images allow to visualize the director orientation and the domain walls that are created during switching.