Molecular simulation of chevrons in confined smectic liquid crystals

N. Mottram, R.E. Webster, D.J. Cleaver

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Chevron structures adopted by confined smectic liquid crystals are investigated via molecular dynamics simulations of the Gay-Berne model. The chevrons are formed by quenching nematic films confined between aligning planar substrates whose easy axes have opposing azimuthal components. When the substrates are perfectly smooth, the chevron formed migrates rapidly towards one of the confining walls to yield a tilted layer structure. However, when substrate roughness is included, by introducing a small-amplitude modulation to the particle-substrate interaction well depth, a symmetric chevron is formed which remains stable over sufficiently long run times for detailed structural information, such as the relevant order parameters and director orientation, to be determined. For both smooth and rough boundaries, the smectic order parameter remains nonzero across the entire chevron, implying that layer identity is maintained across the chevron tip. Also, when the surface-stabilized chevron does eventually revert to a tilted layer structure, it does so via surface slippage, such that layer integrity is maintained throughout the chevron to tilted layer relaxation process.
LanguageEnglish
Pages021706-1
Number of pages21705
JournalPhysical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
Volume68
DOIs
Publication statusPublished - 26 Aug 2003

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Molecular Simulation
Liquid Crystal
liquid crystals
Substrate
simulation
Order Parameter
Amplitude Modulation
Quenching
Long-run
Roughness
confining
integrity
Integrity
Molecular Dynamics Simulation
Rough
roughness
quenching
Entire
molecular dynamics
Interaction

Keywords

  • smectics
  • molecular physics
  • liquid crystals
  • chevrons
  • Gay-Berne model

Cite this

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Molecular simulation of chevrons in confined smectic liquid crystals. / Mottram, N.; Webster, R.E.; Cleaver, D.J.

In: Physical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics , Vol. 68, 26.08.2003, p. 021706-1.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Molecular simulation of chevrons in confined smectic liquid crystals

AU - Mottram, N.

AU - Webster, R.E.

AU - Cleaver, D.J.

PY - 2003/8/26

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N2 - Chevron structures adopted by confined smectic liquid crystals are investigated via molecular dynamics simulations of the Gay-Berne model. The chevrons are formed by quenching nematic films confined between aligning planar substrates whose easy axes have opposing azimuthal components. When the substrates are perfectly smooth, the chevron formed migrates rapidly towards one of the confining walls to yield a tilted layer structure. However, when substrate roughness is included, by introducing a small-amplitude modulation to the particle-substrate interaction well depth, a symmetric chevron is formed which remains stable over sufficiently long run times for detailed structural information, such as the relevant order parameters and director orientation, to be determined. For both smooth and rough boundaries, the smectic order parameter remains nonzero across the entire chevron, implying that layer identity is maintained across the chevron tip. Also, when the surface-stabilized chevron does eventually revert to a tilted layer structure, it does so via surface slippage, such that layer integrity is maintained throughout the chevron to tilted layer relaxation process.

AB - Chevron structures adopted by confined smectic liquid crystals are investigated via molecular dynamics simulations of the Gay-Berne model. The chevrons are formed by quenching nematic films confined between aligning planar substrates whose easy axes have opposing azimuthal components. When the substrates are perfectly smooth, the chevron formed migrates rapidly towards one of the confining walls to yield a tilted layer structure. However, when substrate roughness is included, by introducing a small-amplitude modulation to the particle-substrate interaction well depth, a symmetric chevron is formed which remains stable over sufficiently long run times for detailed structural information, such as the relevant order parameters and director orientation, to be determined. For both smooth and rough boundaries, the smectic order parameter remains nonzero across the entire chevron, implying that layer identity is maintained across the chevron tip. Also, when the surface-stabilized chevron does eventually revert to a tilted layer structure, it does so via surface slippage, such that layer integrity is maintained throughout the chevron to tilted layer relaxation process.

KW - smectics

KW - molecular physics

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KW - Gay-Berne model

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