Rheology of lamellar liquid crystals in two and three dimensions: a simulation study

O. Henrich, K. Stratford, D. Marenduzzo, P. V. Coveney, M. E. Cates

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We present large scale computer simulations of the nonlinear bulk rheology of lamellar phases (smectic liquid crystals) at moderate to large values of the shear rate (Peclet numbers 10-100), in both two and three dimensions. In two dimensions we find that modest shear rates align the system and stabilise an almost regular lamellar phase, but high shear rates induce the nucleation and proliferation of defects, which in steady state is balanced by the annihilation of defects of opposite sign. The critical shear rate at onset of this second regime is controlled by thermodynamic and kinetic parameters; we offer a scaling analysis that relates the critical shear rate to a critical "capillary number" involving those variables. Within the defect proliferation regime, the defects may be partially annealed by slowly decreasing the applied shear rate; this causes marked memory effects, and history-dependent rheology. Simulations in three dimensions show instead shear-induced ordering even at the highest shear rates studied here. This suggests that the critical shear rate shifts markedly upward on increasing dimensionality. This may in part reflect the reduced constraints on defect motion, allowing them to find and annihilate each other more easily. Residual edge defects in the 3D aligned state mostly point along the flow velocity, an orientation impossible in two dimensions.
LanguageEnglish
Pages3817-3831
Number of pages15
JournalSoft Matter
Volume8
Issue number14
Early online date24 Feb 2012
DOIs
Publication statusPublished - 14 Apr 2012

Fingerprint

Liquid Crystals
Rheology
rheology
Shear deformation
liquid crystals
shear
Defects
simulation
defects
Smectic liquid crystals
Peclet number
Kinetic parameters
Flow velocity
Nucleation
Thermodynamics
flow velocity
computerized simulation
Data storage equipment
histories
nucleation

Keywords

  • computer simulations
  • defects
  • elasticity
  • lamellar structures
  • rheology
  • smectic liquid crystal

Cite this

Henrich, O., Stratford, K., Marenduzzo, D., Coveney, P. V., & Cates, M. E. (2012). Rheology of lamellar liquid crystals in two and three dimensions: a simulation study. Soft Matter, 8(14), 3817-3831. https://doi.org/10.1039/C2SM07374A
Henrich, O. ; Stratford, K. ; Marenduzzo, D. ; Coveney, P. V. ; Cates, M. E. / Rheology of lamellar liquid crystals in two and three dimensions : a simulation study. In: Soft Matter. 2012 ; Vol. 8, No. 14. pp. 3817-3831.
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Henrich, O, Stratford, K, Marenduzzo, D, Coveney, PV & Cates, ME 2012, 'Rheology of lamellar liquid crystals in two and three dimensions: a simulation study' Soft Matter, vol. 8, no. 14, pp. 3817-3831. https://doi.org/10.1039/C2SM07374A

Rheology of lamellar liquid crystals in two and three dimensions : a simulation study. / Henrich, O.; Stratford, K.; Marenduzzo, D.; Coveney, P. V.; Cates, M. E.

In: Soft Matter, Vol. 8, No. 14, 14.04.2012, p. 3817-3831.

Research output: Contribution to journalArticle

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