Origin of spontaneous polarisation, tilt and chiral structure of smectic liquid crystal phases composed of bent-core molecules. A molecular model

A.V. Emelyanenko, M.A. Osipov

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

A simple molecular model is proposed for novel bent-core smectic phases that enables one to explain the origin of the experimentally observed chiral structure of the B2 phase composed of nonchiral banana-shaped molecules. It is shown that in the perfectly ordered smectic phase the distributed dispersion interaction between banana-shaped molecules stabilizes the spontaneous polarization and may be responsible for the tilt of the director. The orientation of the spontaneous polarization with respect to the tilt plane is determined by the balance between the dispersion and electrostatic dipole-dipole intermolecular interactions. In particular, sufficiently strong dipole-dipole interaction promotes the B2 phase where the polarization is normal to the tilt plane. The actual chiral structure of each smectic layer in the B2 phase appears as a result of the symmetry breaking. In the case of small molecular dipoles the nonchiral polar smectic phase is formed where the spontaneous polarization is parallel to the tilt plane. The role of the opening angle and of the axial ratio of banana-shaped molecules is also considered and a phase diagram is presented.
LanguageEnglish
Pages1-8
Number of pages7
JournalPhysical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
Volume70
Issue number021704
DOIs
Publication statusPublished - Aug 2004

Fingerprint

Tilt
Liquid Crystal
Polarization
Dipole
liquid crystals
Molecules
dipoles
polarization
molecules
Interaction
Model
interactions
broken symmetry
Symmetry Breaking
Electrostatics
Phase Diagram
phase diagrams
electrostatics
Angle

Keywords

  • bent-core molecules
  • banana-shaped molecules
  • spontaneous polarization
  • tilt
  • chiral structure
  • liquid-crystal

Cite this

@article{098873f217fb43de948ab56aa67e66f3,
title = "Origin of spontaneous polarisation, tilt and chiral structure of smectic liquid crystal phases composed of bent-core molecules. A molecular model",
abstract = "A simple molecular model is proposed for novel bent-core smectic phases that enables one to explain the origin of the experimentally observed chiral structure of the B2 phase composed of nonchiral banana-shaped molecules. It is shown that in the perfectly ordered smectic phase the distributed dispersion interaction between banana-shaped molecules stabilizes the spontaneous polarization and may be responsible for the tilt of the director. The orientation of the spontaneous polarization with respect to the tilt plane is determined by the balance between the dispersion and electrostatic dipole-dipole intermolecular interactions. In particular, sufficiently strong dipole-dipole interaction promotes the B2 phase where the polarization is normal to the tilt plane. The actual chiral structure of each smectic layer in the B2 phase appears as a result of the symmetry breaking. In the case of small molecular dipoles the nonchiral polar smectic phase is formed where the spontaneous polarization is parallel to the tilt plane. The role of the opening angle and of the axial ratio of banana-shaped molecules is also considered and a phase diagram is presented.",
keywords = "bent-core molecules, banana-shaped molecules, spontaneous polarization, tilt, chiral structure, liquid-crystal",
author = "A.V. Emelyanenko and M.A. Osipov",
year = "2004",
month = "8",
doi = "10.1103/PhysRevE.70.021704",
language = "English",
volume = "70",
pages = "1--8",
journal = "Physical Review E",
issn = "1539-3755",
publisher = "American Physical Society",
number = "021704",

}

TY - JOUR

T1 - Origin of spontaneous polarisation, tilt and chiral structure of smectic liquid crystal phases composed of bent-core molecules. A molecular model

AU - Emelyanenko, A.V.

AU - Osipov, M.A.

PY - 2004/8

Y1 - 2004/8

N2 - A simple molecular model is proposed for novel bent-core smectic phases that enables one to explain the origin of the experimentally observed chiral structure of the B2 phase composed of nonchiral banana-shaped molecules. It is shown that in the perfectly ordered smectic phase the distributed dispersion interaction between banana-shaped molecules stabilizes the spontaneous polarization and may be responsible for the tilt of the director. The orientation of the spontaneous polarization with respect to the tilt plane is determined by the balance between the dispersion and electrostatic dipole-dipole intermolecular interactions. In particular, sufficiently strong dipole-dipole interaction promotes the B2 phase where the polarization is normal to the tilt plane. The actual chiral structure of each smectic layer in the B2 phase appears as a result of the symmetry breaking. In the case of small molecular dipoles the nonchiral polar smectic phase is formed where the spontaneous polarization is parallel to the tilt plane. The role of the opening angle and of the axial ratio of banana-shaped molecules is also considered and a phase diagram is presented.

AB - A simple molecular model is proposed for novel bent-core smectic phases that enables one to explain the origin of the experimentally observed chiral structure of the B2 phase composed of nonchiral banana-shaped molecules. It is shown that in the perfectly ordered smectic phase the distributed dispersion interaction between banana-shaped molecules stabilizes the spontaneous polarization and may be responsible for the tilt of the director. The orientation of the spontaneous polarization with respect to the tilt plane is determined by the balance between the dispersion and electrostatic dipole-dipole intermolecular interactions. In particular, sufficiently strong dipole-dipole interaction promotes the B2 phase where the polarization is normal to the tilt plane. The actual chiral structure of each smectic layer in the B2 phase appears as a result of the symmetry breaking. In the case of small molecular dipoles the nonchiral polar smectic phase is formed where the spontaneous polarization is parallel to the tilt plane. The role of the opening angle and of the axial ratio of banana-shaped molecules is also considered and a phase diagram is presented.

KW - bent-core molecules

KW - banana-shaped molecules

KW - spontaneous polarization

KW - tilt

KW - chiral structure

KW - liquid-crystal

UR - http://dx.doi.org/10.1103/PhysRevE.70.021704

U2 - 10.1103/PhysRevE.70.021704

DO - 10.1103/PhysRevE.70.021704

M3 - Article

VL - 70

SP - 1

EP - 8

JO - Physical Review E

T2 - Physical Review E

JF - Physical Review E

SN - 1539-3755

IS - 021704

ER -