Nagaraj, M, Usami, K, Zhang, Z et al. (3 more authors) (2014) Unusual electric-field-induced transformations in the dark conglomerate phase of a bent-core liquid crystal. Liquid Crystals, 41 (6). 800 - 811. ISSN 0267-8292
Abstract
Unusual behaviour of the dark conglomerate (DC) phase seen in an oxadiazole-based achiral bent-core liquid crystal, which has not previously been reported for the DC phase of other liquid crystals, is described. Under polarising optical microscopy, we see no domains of opposite handedness in the ground state of the DC phase. However, it shows unusual transformations when an electric field is applied to the system. On increasing the electric field, at first the domains of opposite handedness become visible and then they grow in size and slowly the sample transforms to a monochiral or single-handed form which is followed by a nonchiral state at very high fields. The threshold electric fields required to achieve these changes are temperature dependent and the transformations are seen irrespective of the frequency of the applied electric field (100 Hz to 5 kHz), type of the waveform (sine, square and triangular) and the thickness (1.5 μm to 15 μm) or the geometry (planar and twisted) of the device used. Further, there is no field-induced high birefringence texture observed even though sufficiently large electric field (~22 V/μm) has been applied across the devices. The nature of the behaviour is investigated by various techniques such as optical microscopy, conoscopy, circular dichroic and Raman spectroscopies, electro-optics and dielectric spectroscopy. The possible physical phenomena behind these changes are discussed in detail.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014 Taylor & Francis. This is an Accepted Manuscript of an article published by Taylor & Francis in Liquid Crystals on 06/02/14 available online: http://wwww.tandfonline.com/10.1080/02678292.2014.885602 |
Keywords: | Bent-core liquid crystal; dark conglomerate phase; chirality |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Physics & Astronomy Visitors (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Soft Matter Physics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 20 Oct 2015 10:38 |
Last Modified: | 21 Jan 2018 05:50 |
Published Version: | http://dx.doi.org/10.1080/02678292.2014.885602 |
Status: | Published |
Publisher: | Taylor & Francis |
Identification Number: | 10.1080/02678292.2014.885602 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:86444 |