Oligomeric odd-even effect in liquid crystals
Saha, Rony; Babakhanova, Greta; Parsouzi, Zeinab; Rajabi, Mojtaba; Gyawali, Prabesh; Welch, Chris; Mehl, Georg H; Gleeson, Jim T.; Lavrentovich, Oleg D.; Sprunt, Samuel; Jakli, Antal
Professor Georg Mehl G.H.Mehl@hull.ac.uk
Professor of Organic and Materials Chemistry
Jim T. Gleeson
Oleg D. Lavrentovich
Odd-even effects, oscillations in properties of materials comprised of an odd or even number of connected repeating units, are well-known phenomena in materials science. In organic materials, they are usually associated with the number of methylene groups in aliphatic chains. In this work, we unveil multiple signatures of a new odd-even effect in liquid crystals that occurs at the larger scale of molecular moieties that by themselves express liquid crystalline behavior. We demonstrate that oligomeric liquid crystals, with n=1-4 number of rigid mesogenic segments connected by flexible aliphatic chains with an odd number of methylene groups, produce an odd-even effect in optical anisotropy and the bend elastic constant of the liquid crystal oligomer. This effect is different from the usual odd-even effects with respect to the parity of carbon atoms in an aliphatic chain and can be understood in term of the average molecular shape and the associations between n-mers based on the packing of these shapes. We also show that, in spite of the fact that there is no long-range electron density modulation, careful analysis of synchrotron SAXS results can provide important information about the molecular associations in the N and NTB phases that other techniques cannot access. This novel odd-even effect opens up a new mode to optimize phase and optical behavior.
|Journal Article Type||Article|
|Publication Date||Jun 13, 2019|
|Peer Reviewed||Peer Reviewed|
|Institution Citation||Saha, R., Babakhanova, G., Parsouzi, Z., Rajabi, M., Gyawali, P., Welch, C., …Jakli, A. (2019). Oligomeric odd-even effect in liquid crystals. Materials Horizons, https://doi.org/10.1039/c9mh00428a|
This file is under embargo until Jun 14, 2020 due to copyright reasons.
Contact G.H.Mehl@hull.ac.uk to request a copy for personal use.
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