The Chiral Twist-Bend Nematic Phase (N*TB)

Rebecca Walker* (Corresponding Author), Damian Pociecha, John Mervyn David Storey, Ewa Gorecka, Corrie Thomas Imrie

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The twist‐bend nematic, NTB, phase has been observed for chiral materials in which chirality is introduced through a branched 2‐methylbutyl terminal tail. The chiral twist‐bend nematic phase, N*TB, is completely miscible with the NTB phase of the standard achiral material, CB6OCB. The N*TB phase exhibits optical textures with lower birefringence than those observed for the achiral NTB phase, suggesting an additional mechanism of averaging molecular orientations. The N*−N*TB transition temperatures for the chiral materials are higher than the NTB−N transition temperatures seen for the corresponding racemic materials. This suggests the double degeneracy of helical twist sense in the  phase is removed by the intrinsic molecular chirality. A square lattice pattern is observed in the N* phase over a temperature range of several degrees above the N*TB–N phase transition, which may be attributed to a non‐monotonic dependence of the bend elastic constant.
Original languageEnglish
Pages (from-to)13329-13335
Number of pages7
JournalChemistry : a European Journal
Volume25
Issue number58
Early online date5 Sep 2019
DOIs
Publication statusPublished - 17 Oct 2019

Fingerprint

Chirality
Molecular orientation
Elastic constants
Birefringence
Superconducting transition temperature
Textures
Phase transitions
Temperature

Keywords

  • liquid crystals
  • chirality
  • spontaneous symmetry breaking
  • twist-bend nematic phase
  • BEHAVIOR
  • LIQUID-CRYSTAL DIMERS
  • SYMMETRY-BREAKING

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Organic Chemistry

Cite this

The Chiral Twist-Bend Nematic Phase (N*TB). / Walker, Rebecca (Corresponding Author); Pociecha, Damian; Storey, John Mervyn David; Gorecka, Ewa; Imrie, Corrie Thomas.

In: Chemistry : a European Journal, Vol. 25, No. 58, 17.10.2019, p. 13329-13335.

Research output: Contribution to journalArticle

Walker, Rebecca ; Pociecha, Damian ; Storey, John Mervyn David ; Gorecka, Ewa ; Imrie, Corrie Thomas. / The Chiral Twist-Bend Nematic Phase (N*TB). In: Chemistry : a European Journal. 2019 ; Vol. 25, No. 58. pp. 13329-13335.
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abstract = "The twist‐bend nematic, NTB, phase has been observed for chiral materials in which chirality is introduced through a branched 2‐methylbutyl terminal tail. The chiral twist‐bend nematic phase, N*TB, is completely miscible with the NTB phase of the standard achiral material, CB6OCB. The N*TB phase exhibits optical textures with lower birefringence than those observed for the achiral NTB phase, suggesting an additional mechanism of averaging molecular orientations. The N*−N*TB transition temperatures for the chiral materials are higher than the NTB−N transition temperatures seen for the corresponding racemic materials. This suggests the double degeneracy of helical twist sense in the  phase is removed by the intrinsic molecular chirality. A square lattice pattern is observed in the N* phase over a temperature range of several degrees above the N*TB–N phase transition, which may be attributed to a non‐monotonic dependence of the bend elastic constant.",
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