A novel model for smectic liquid crystals: Elastic anisotropy and response to a steady-state flow.
J Chem Phys
; 145(16): 164903, 2016 Oct 28.
Article
em En
| MEDLINE
| ID: mdl-27802618
ABSTRACT
By means of a combination of equilibrium Monte Carlo and molecular dynamics simulations and nonequilibrium molecular dynamics we investigate the ordered, uniaxial phases (i.e., nematic and smectic A) of a model liquid crystal. We characterize equilibrium behavior through their diffusive behavior and elastic properties. As one approaches the equilibrium isotropic-nematic phase transition, diffusion becomes anisotropic in that self-diffusion D⥠in the direction orthogonal to a molecule's long axis is more hindered than self-diffusion D⥠in the direction parallel to that axis. Close to nematic-smectic A phase transition the opposite is true, D⥠< Dâ¥. The Frank elastic constants K1, K2, and K3 for the respective splay, twist, and bend deformations of the director field nÌ are no longer equal and exhibit a temperature dependence observed experimentally for cyanobiphenyls. Under nonequilibrium conditions, a pressure gradient applied to the smectic A phase generates Poiseuille-like or plug flow depending on whether the convective velocity is parallel or orthogonal to the plane of smectic layers. We find that in Poiseuille-like flow the viscosity of the smectic A phase is higher than in plug flow. This can be rationalized via the velocity-field component in the direction of the flow. In a sufficiently strong flow these smectic layers are not destroyed but significantly bent.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Alemanha