Document Type
Article
Publication Date
12-4-2009
Abstract
A substrate coated with a polyimide alignment layer is scribed bidirectionally with the stylus of an atomic force microscope to create an easy axis for liquid-crystal orientation. The resulting noncentrosymmetric topography breaks two-dimensional inversion symmetry and results in a spatial amplitude modulation of an imposed twisted nematic state. This is observed optically as spatially periodic light and dark stripes. When the alignment layer is scribed unidirectionally the centrosymmetric topography maintains inversion symmetry, and no stripes are observed. The appearance of the twist modulation is consistent with a chiral term in the free energy.
Keywords
alignment layers, centrosymmetric, dark stripe, easy axis, inversion symmetry, liquid-crystal orientation, nematic cells, non-centrosymmetric, polyimide alignment layers, spatial amplitude, surface chirality, twisted nematic, alignment, modulation, nematic liquid crystals, polyimides, single crystals, stereochemistry, two dimensional, crystal orientation, atomic force microscopes
Publication Title
Physical Review E
Rights
© 2009 The American Physical Society.
Recommended Citation
Patterning-Induced Surface Chirality and Modulation of Director Twist in a Nematic Cell. Choi Y., Atherton T., Ferjani S., Petschek R.G., Rosenblatt C., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 80:6, 2009.