Warren D. Stevenson
Macroscopic chirality of twist-bend nematic phase in bent dimers confirmed by circular dichroism
Stevenson, Warren D.; Zeng, Xiangbing; Welch, Chris; Thakur, Anil K.; Ungar, Goran; Mehl, Georg H.
Anil K. Thakur
Professor Georg Mehl G.H.Mehl@hull.ac.uk
Professor of Organic and Materials Chemistry
Many achiral bent molecules and some polymers with such repeat units exhibit a liquid crystal phase transition between a conventional nematic (N), and a second nematic (Nx) with periodically modulated orientation. Theory predicts several possible structures for the Nx phase, some of which are chiral (helical), and others achiral (e.g. zigzag). Experimentally distinguishing which modulation type is present is non-trivial and the structure is often assumed to be helical despite the other possibilities. Here we use circular dichroism (CD) spectroscopy to directly and unambiguously identify chirality in the Nx phase of two different dimer series, “DTC5Cn” and “CBCnCB”, which vary in (CH2)n spacer length (n=5, 7, 9). In doing so we have determined that the modulation type is helical in all samples. The temperature dependence of the CD signal was also investigated, suggesting that the helical structure progressively unwinds on approach to the high temperature N phase
Stevenson, W. D., Zeng, X., Welch, C., Thakur, A. K., Ungar, G., & Mehl, G. H. (2020). Macroscopic chirality of twist-bend nematic phase in bent dimers confirmed by circular dichroism. Journal of materials chemistry. C, 8, 1041-1047. https://doi.org/10.1039/c9tc05061b
|Journal Article Type||Article|
|Acceptance Date||Dec 3, 2019|
|Online Publication Date||Dec 6, 2019|
|Deposit Date||Feb 18, 2020|
|Publicly Available Date||Nov 30, -0001|
|Journal||Journal of Materials Chemistry C|
|Publisher||Royal Society of Chemistry|
|Peer Reviewed||Peer Reviewed|
|Keywords||Materials Chemistry; General Chemistry|
|Additional Information||: This document is Similarity Check deposited; : Supplementary Information; : Xiangbing Zeng (ORCID); : Chris Welch (ORCID); : Goran Ungar (ORCID); : Georg H. Mehl (ORCID); : Single-blind; : Received 13 September 2019; Accepted 3 December 2019; Accepted Manuscript published 6 December 2019; Advance Article published 12 December 2019|
This file is under embargo due to copyright reasons.
Contact G.H.Mehl@hull.ac.uk to request a copy for personal use.
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