New patterns of twist-bend liquid crystal phase behaviour: the synthesis and characterisation of the 1-(4-cyanobiphenyl-4′-yl)-10-(4-alkylaniline-benzylidene-4′-oxy)decanes (CB10O·m)

Ahlam F. Alshammari, Damian Pociecha, Rebecca Walker, John M.D. Storey, Ewa Gorecka, Corrie T. Imrie* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

The synthesis and characterisation of the 1-(4-cyanobiphenyl-4′-yl)-10-(4-alkylanilinebenzylidene-4′-oxy)decanes (CB10O·m) are reported. This series shows a rich liquid crystal polymorphism including twist-bend nematic and smectic phases. All the homologues reported exhibit an enantiotropic conventional nematic phase. For the homologues with m ≤ 10, the local packing in the nematic phases and the layer spacing in the smectic phases indicates an intercalated arrangement of the molecules. An intercalated smectic CA phase is observed if m/11 ≈ 0.5. Either side of this condition, the twist-bend nematic phase is observed, a novel pattern of behaviour for a series on increasing a terminal chain length. For longer chain lengths, m = 12, 14, 16 and 18, two twist-bend smectic C (SmCTB) phases are observed, and the packing of the molecules is now of a bilayer-type. The higher temperature variant is termed SmCTB-SH in which SH (single helix) refers to the presence of a short, distorted clock-type helix. In the lower temperature SmCTB-DH phase, an additional longer helix is superimposed on the short one, and DH denotes double helix.

Original languageEnglish
Pages (from-to)4679-4688
Number of pages10
JournalSoft matter
Volume18
Issue number25
Early online date30 May 2022
DOIs
Publication statusPublished - 7 Jul 2022

Bibliographical note

Open Access via the RSC OA Agreement
Funding Information:
A. F. A. wishes to thank the Ministry of Education and the University of Hail, Saudi Arabia through the Cultural Bureau of Saudi Arabia, London for their financial support during the study period. E. G. and D. P. thank the National Science Centre (Poland) for financial support under the grant no. 2016/22/A/ST5/00319.

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