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Proceedings Paper

Properties of the self-deforming Ntb phase in mesogenic dimers
Author(s): Vitaly P. Panov; Jagdish K. Vij; Reshma Balachandran; Volodymyr Borshch; Oleg D. Lavrentovich; Maria G. Tamba; Georg H. Mehl
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Paper Abstract

An overview of the results obtained from the most recent experiments performed for revealing the structure of the twistbend nematic Ntb phase will be presented at the conference. This new phase provides typical X-ray diffraction pattern for the nematic phase and is found at temperatures below the conventional nematic phase in odd-chain hydrocarbon linked mesogenic dimers. The materials in the Ntb phase form self-deformed striped pattern parallel to the rubbing direction in planarly aligned rubbed cells with a well-defined period. The period is found to depend on the cell spacing. The selfdeformation stripes appear without any external electromagnetic field or thickness gradient across the cell. Although the materials are composed of non-chiral molecules, the low temperature nematic phase exhibits fast linear optical response of the order of a few microseconds. This response is reminiscent of the phase exhibiting chirality. Moreover, at higher fields some of the materials form striped domains with opposite direction of the optical response. These stripes appear normal to the rubbing direction and their periodicity depends on voltage and frequency. The Freedericksz transition in this phase also shows unusual properties and this is proven to be of the first order. The techniques to characterize this phase include polarized microscopy observation and optical contrast spectroscopy. Possible causes of the phenomena will be discussed.

Paper Details

Date Published: 12 September 2013
PDF: 7 pages
Proc. SPIE 8828, Liquid Crystals XVII, 88280X (12 September 2013); doi: 10.1117/12.2024470
Show Author Affiliations
Vitaly P. Panov, Trinity College Dublin (Ireland)
Jagdish K. Vij, Trinity College Dublin (Ireland)
Reshma Balachandran, Trinity College Dublin (Ireland)
Volodymyr Borshch, Kent State Univ. (United States)
Oleg D. Lavrentovich, Kent State Univ. (United States)
Maria G. Tamba, Univ. of Hull (United Kingdom)
Georg H. Mehl, Univ. of Hull (United Kingdom)

Published in SPIE Proceedings Vol. 8828:
Liquid Crystals XVII
Iam Choon Khoo, Editor(s)

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