Domain walls in two-dimensional nematics confined in a small circular cavity

Abstract

Using Monte Carlo simulation, we study a fluid of two-dimensional hard rods inside a small circular cavity bounded by a hard wall, from the dilute regime to the high-density, layering regime. Both planar and homeotropic anchoring of the nematic director can be induced at the walls through a free-energy penalty. The circular geometry creates frustration in the nematic phase and a polar-symmetry configuration with a distorted director field plus two $+1/2$ disclinations is created. At higher densities, a quasi-uniform structure is observed with a (minimal) director distortion which is relaxed via the formation of orientational domain walls. This novel structure is not predicted by elasticity theory and is similar to the step-like structures observed in three-dimensional hybrid slit pores. We speculate that the formation of domain walls is a general mechanism to relax elastic stresses in conditions of strong surface anchoring and severe spatial confinement.

11 pages, 6 figures. Soft Matter, 2014

References in corpus (7)

• Spontaneous Circulation of Confined Active Suspensions
• Topological Defects in Spherical Nematics
• Orientational ordering in hard rectangles: The role of three-body correlations
• Theory and simulation of two-dimensional nematic and tetratic phases
• Capillary ordering and layering transitions in two-dimensional hard-rod fluids
• Demixing and orientational ordering in mixtures of rectangular particles
• Enhanced stability of tetratic phase due to clustering

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• Ordering in granular rod monolayers driven far from thermodynamic equilibrium
• Defect patterns of two-dimensional nematic liquid crystals in confinement
• Ordering of hard rectangles in strong confinement
• Viral nematics in confined geometries
• Uniform phases in fluids of hard isosceles triangles: one component and binary mixtures
• Domain walls in vertically vibrated monolayers of cylinders confined in annuli
• Defects in vertically vibrated monolayers of cylinders
• Biaxial layering transition of hard rod-like particles in narrow slit-like pores
• Hard rectangles near curved hard walls: tuning the sign of the Tolman length
• Confinement effects on the random sequential adsorption packings of elongated particles in a slit
• Exotic liquid crystalline phases in monolayers of vertically vibrated granular particles
• Highly confined mixtures of parallel hard squares: A Density Functional Theory study