Young-Ki Kim
Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes
Kim, Young-Ki; Senyuk, Bohdan; Shin, Sung-Tae; Kohlmeier, Alexandra; Mehl, Georg H.; Lavrentovich, Oleg D.
Authors
Bohdan Senyuk
Sung-Tae Shin
Alexandra Kohlmeier
Professor Georg Mehl G.H.Mehl@hull.ac.uk
Professor of Organic and Materials Chemistry
Oleg D. Lavrentovich
Abstract
We address the status of oxadiazole mesogens, C7 and C12, reported to show the biaxial nematic phase, by exploring material aspects (chemical stability, surface anchoring, optical and dielectric properties, topological defects) linked to the type of nematic order. We demonstrate that the isogyres splitting in conoscopic patterns of homeotropic state depends on sample thickness and is associated with variations of molecular tilt along the normal to substrates. We observe isolated topological point defects (boojums and hedgehogs), as well as nonsingular “escaped” disclinations pertinent only to the uniaxial nematic order. Our conclusion is that C7 and C12 feature only a uniaxial nematic phase and the apparent biaxiality is caused by surface effects.
Citation
Kim, Y., Senyuk, B., Shin, S., Kohlmeier, A., Mehl, G. H., & Lavrentovich, O. D. (2014). Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes. Molecular crystals and liquid crystals, 540(1), 20-41. https://doi.org/10.1039/C3SM52249K
Journal Article Type | Article |
---|---|
Acceptance Date | Nov 1, 2013 |
Online Publication Date | Nov 5, 2013 |
Publication Date | Jan 1, 2014 |
Deposit Date | Dec 24, 2015 |
Publicly Available Date | Nov 23, 2017 |
Journal | Molecular crystals and liquid crystals |
Print ISSN | 1542-1406 |
Electronic ISSN | 1563-5287 |
Publisher | Taylor and Francis |
Peer Reviewed | Peer Reviewed |
Volume | 540 |
Issue | 1 |
Pages | 20-41 |
DOI | https://doi.org/10.1039/C3SM52249K |
Keywords | Thermotropic nematic phase |
Public URL | https://hull-repository.worktribe.com/output/383630 |
Publisher URL | http://www.tandfonline.com/doi/abs/10.1080/15421406.2011.568324 |
Additional Information | This is an author's accepted manuscript of an article published in Molecular crystals and liquid crystals, 2011, v.540 issue 1. |
Files
Article.pdf
(1.1 Mb)
PDF
Copyright Statement
©2015 University of Hull
You might also like
Nematic twist-bend phase with nanoscale modulation of molecular orientation
(2013)
Journal Article
Sound absorption of porous cement composites: effects of the porosity and the pore size
(2015)
Journal Article
NMR study of a bimesogenic liquid crystal with two nematic phases
(2015)
Journal Article