Multistability in planar liquid crystal wells.

Journal article

A planar bistable liquid crystal device, reported in Tsakonas et al. [Appl. Phys. Lett. 90, 111913 (2007)], is modeled within the Landau-de Gennes theory for nematic liquid crystals. This planar device consists of an array of square micrometer-sized wells. We obtain six different classes of equilibrium profiles and these profiles are classified as diagonal or rotated solutions. In the strong anchoring case, we propose a Dirichlet boundary condition that mimics the experimentally imposed tangent boundary conditions. In the weak anchoring case, we present a suitable surface energy and study the multiplicity of solutions as a function of the anchoring strength. We find that diagonal solutions exist for all values of the anchoring strength W ≥ 0, while rotated solutions only exist for W ≥ W_{c}>0, where W_{c} is a critical anchoring strength that has been computed numerically. We propose a dynamic model for the switching mechanisms based on only dielectric effects. For sufficiently strong external electric fields, we numerically demonstrate diagonal-to-rotated and rotated-to-diagonal switching by allowing for variable anchoring strength across the domain boundary.

Authors: Luo, C; Majumdar, A; Erban, R

• Journal: Physical review. E, Statistical, nonlinear, and soft matter physics
• Volume: 85
• Issue: 6 Pt 1
• Pages: 061702
• Publication date: 2012-06-01
• DOI: 10.1103/physreve.85.061702
• EISSN: 1550-2376
• ISSN: 1539-3755
• Language: English
• Keywords: Models, Molecular; Membranes, Artificial; Liquid Crystals; Crystallization; Computer Simulation; Models, Chemical; Phase Transition