Electric field-induced crossover from 3D to 2D topological defects in a nematic liquid crystal: experimental verification. Issue 3 (6th November 2019)

• Record Type: Journal Article
• Authors: Ferris, Andrew J.; Afghah, Sajedeh; Selinger, Robin L. B.; Selinger, Jonathan V.; Rosenblatt, Charles
• Is Part Of: Soft matter. Volume 16:Issue 3(2019)
• Page Start: 642
• Page End: 650
• Publication Date: 2019-11-06
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c9sm01733j
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : A substrate was patterned with two pairs of half-integer strength topological defects, (+1/2, +1/2) and (+1/2, −1/2). Abstract : A substrate was patterned with two pairs of half-integer strength topological defects, (+1/2, +1/2) and (+1/2, −1/2). In a sufficiently thick cell, a disclination line runs in an arch above the substrate connecting the two half integer defects within each pair. The director around the disclination line for the like-sign pair must rotate in 3D, whereas for the opposite-sign defect pair the director lies in the xy -plane parallel to the substrate. For a negative dielectric anisotropy nematic, an electric field applied normal to the substrate drives the director into the xy -plane, forcing the arch of the disclination line of the like-sign pair to become extended along the z -axis. For sufficiently large field the arch splits, resulting in two nearly parallel disclination lines traversing the cell from one substrate to the other. The opposite-sign defect pair is largely unaffected by the electric field as the director already lies in the xy -plane. Experimental results are presented, which are consistent with numerical simulations.