8/16/2023 0 Comments Zigzag lines in fish meat![]() ![]() Patterned surfaces 15, 16, 17 are also used to induce regularly distorted alignments. ![]() Although a uniform n would minimize the Frank elastic energy density in the bulk, various distorted alignments appear when the LC is confined in specific geometries, such as the twisted N cell, hybrid alignments 2, 3, 4, 5, 6, 7, capillary tubes 8, 9, 10, emulsion droplets 11, 12, thin cells 13 and shells 14. The geometry of the confining surfaces and the interaction between a surface and NLC molecules, called the surface anchoring, have a crucial role in the control of LC alignment. The static profile of the director is determined by minimising the Frank elastic energy under the boundary conditions imposed at the surfaces confining the NLC. The free energy of an NLC in terms of n, called the Frank elastic energy, is expressed by F=(1/2)∫d r, where K 11, K 22 and K 33 are elastic constants for splay, twist and bend distortions, respectively. The local orientational order of an NLC is specified by a unit vector, n, known as the director. Nematic (N) liquid crystals (LCs) are anisotropic fluids with long-range molecular orientational order and no positional order of their constituent molecules 1. Our system, which uses easily fabricated microwrinkle grooves, provides a new microfabrication method based on the arrangement of controllable defects. Moreover, the kinks in the zigzag defects can trap small particles, which may afford a new method for manipulation of colloids. The periodic structure can be tuned by controlling the groove geometry and the molecular chirality, which demonstrates the importance of boundary conditions and introduced asymmetry for the engineering of topological defects. This periodic ordering results from the inherent liquid crystal elastic anisotropy and the antagonistic boundary conditions at the flat liquid crystal–air and the curved liquid crystal–groove interfaces. Here we show that a nematic liquid crystal, when confined in a sinusoidal microwrinkle groove, exhibits a new periodic arrangement of twist deformations and a zigzag line defect. Spatially confined liquid crystals exhibit non-uniform alignment, often accompanied by self-organised topological defects of non-trivial shape in response to imposed boundary conditions and geometry. ![]()
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