Fig. 5

Director profile in the surface patterned cell in the area of square web of disclinations. a Schematic illustration of square web of disclinations in a nematic LC cell held between the patterned substrates. Periodic arrays of twist disclinations (red lines) are generated by the periodic orientational patterns on the top and bottom substrates (the two lines along the y-axis are generated from top surface, while the lines along z-axis are produced by surface alignment from bottom substrate), and are stably located by elastic forces a few micrometers apart from one another at the intersections. The intersections of the disclination lines, highlighted by eye-guiding yellow strips giving the sheets of directors, are anchored where the directors on the bottom and the top surfaces are parallel, whereas the middle points of the line are positioned at the place of ±π/2 twist. b Position dependence of the azimuthal orientation of LC director on the square patterned substrate. Flipping this substrate over to have the top substrate, we see that the azimuthal angle changes its sign irrespective of the manner it is flipped, i.e., φ ₂ = −φ ₁. c Position dependence of the twist angle, φ _t = φ ₂ − φ ₁, in the assembled liquid crystal cell