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Statics and kinetics at the nematic­-isotropic interface: effects of biaxiality

Statics and kinetics at the nematic­-isotropic interface: effects of biaxiality
Statics and kinetics at the nematic­-isotropic interface: effects of biaxiality
We use the Landau-de Gennes theory of a nematic liquid crystal to investigate anew aspects of the properties of the interface between the isotropic and nematic liquid crystal phases of the same fluid. The equations of the static interface have been solved, both numerically and using asymptotic analysis, with an emphasis on the effect of inclusion of the order parameter biaxiality on the physical properties. We have compared the results of the exact solutions to the commonly used de Gennes ansatz, which assumes positive and uniform unixiality through the interface. Although the de Gennes ansatz in general gives good results, when bend and splay elastic constants dominate over the twist constants, it can lead to errors of up to 10% in the surface energy. The asymptotic analysis also shows that, by contrast with the de Gennes ansatz, the order parameter wings in the isotropic phase exhibit negative order parameter, with principal axis perpendicular to the surface. For moving interfaces, using an approximation which at this stage does not yet include hydrodynamic coupling, we have compared our results with the analogue of the de Gennes ansatz used by the present authors in an earlier paper. We find that including biaxiality leads to larger effects in the dynamic than in the static properties, and that whereas this is essentially a perturbation to the energy, the velocity of the moving interface can be significantly slowed down. The slowing down effects are strongly correlated with surface biaxiality, but both effects seem to be diminished when the isotropic phase is advancing.
1155-4312
1225-1243
Popa-­Nita, V.
fd6ee09e-8907-4a20-b1d3-b1fed5bdceb1
Sluckin, T.J.
8dbb6b08-7034-4ae2-aa65-6b80072202f6
Wheeler, A.A.
eb831100-6e51-4674-878a-a2936ad04d73
Popa-­Nita, V.
fd6ee09e-8907-4a20-b1d3-b1fed5bdceb1
Sluckin, T.J.
8dbb6b08-7034-4ae2-aa65-6b80072202f6
Wheeler, A.A.
eb831100-6e51-4674-878a-a2936ad04d73

Popa-­Nita, V., Sluckin, T.J. and Wheeler, A.A. (1997) Statics and kinetics at the nematic­-isotropic interface: effects of biaxiality. Journal de Physique II, 7 (9), 1225-1243. (doi:10.1051/jp2:1997183).

Record type: Article

Abstract

We use the Landau-de Gennes theory of a nematic liquid crystal to investigate anew aspects of the properties of the interface between the isotropic and nematic liquid crystal phases of the same fluid. The equations of the static interface have been solved, both numerically and using asymptotic analysis, with an emphasis on the effect of inclusion of the order parameter biaxiality on the physical properties. We have compared the results of the exact solutions to the commonly used de Gennes ansatz, which assumes positive and uniform unixiality through the interface. Although the de Gennes ansatz in general gives good results, when bend and splay elastic constants dominate over the twist constants, it can lead to errors of up to 10% in the surface energy. The asymptotic analysis also shows that, by contrast with the de Gennes ansatz, the order parameter wings in the isotropic phase exhibit negative order parameter, with principal axis perpendicular to the surface. For moving interfaces, using an approximation which at this stage does not yet include hydrodynamic coupling, we have compared our results with the analogue of the de Gennes ansatz used by the present authors in an earlier paper. We find that including biaxiality leads to larger effects in the dynamic than in the static properties, and that whereas this is essentially a perturbation to the energy, the velocity of the moving interface can be significantly slowed down. The slowing down effects are strongly correlated with surface biaxiality, but both effects seem to be diminished when the isotropic phase is advancing.

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Published date: 1997

Identifiers

Local EPrints ID: 373
URI: http://eprints.soton.ac.uk/id/eprint/373
ISSN: 1155-4312
PURE UUID: 67578b7d-e5b6-4c4c-b3e0-c8d638efb290
ORCID for T.J. Sluckin: ORCID iD orcid.org/0000-0002-9163-0061

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Date deposited: 04 Mar 2004
Last modified: 16 Mar 2024 02:32

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Contributors

Author: V. Popa-­Nita
Author: T.J. Sluckin ORCID iD
Author: A.A. Wheeler

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