Issue 9, 2019

Oligomeric odd–even effect in liquid crystals

Abstract

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.

Graphical abstract: Oligomeric odd–even effect in liquid crystals

Article information

Article type
Communication
Submitted
25 Кві 2019
Accepted
13 Чер 2019
First published
13 Чер 2019

Mater. Horiz., 2019,6, 1905-1912

Author version available

Oligomeric odd–even effect in liquid crystals

R. Saha, G. Babakhanova, Z. Parsouzi, M. Rajabi, P. Gyawali, C. Welch, G. H. Mehl, J. Gleeson, O. D. Lavrentovich, S. Sprunt and A. Jákli, Mater. Horiz., 2019, 6, 1905 DOI: 10.1039/C9MH00428A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements