Phase Diagram and Order Reconstruction Modeling for Nematics in Asymmetric π-Cells

• Published in: Symmetry (Basel) Vol. 13; no. 11; p. 2156
• Main Authors: Amoddeo, Antonino, Barberi, Riccardo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.11.2021
• Subjects: Asymmetry; Eigenvalues; Electric fields; FEM; Finite element method; Liquid crystals; Mathematical analysis; MMPDE; nematic asymmetric cell; nematic biaxiality; Nematic crystals; nematic liquid crystals; order reconstruction; Partial differential equations; Phase diagrams; Reconstruction; Symmetry; Tensors
• ISSN: 2073-8994; 2073-8994
• DOI: 10.3390/sym13112156

Intense electric fields applied to an asymmetric π-cell containing a nematic liquid crystal subjected to strong mechanical stresses induce distortions that are relaxed through a fast-switching mechanism: the order reconstruction transition. Topologically different nematic textures are connected by such a mechanism that is spatially driven by the intensity of the applied electric fields and by the anchoring angles of the nematic molecules on the confining plates of the cell. Using the finite element method, we implemented the moving mesh partial differential equation numerical technique, and we simulated the nematic evolution inside the cell in the context of the Landau–de Gennes order tensor theory. The order dynamics have been well captured, putting in evidence the possible existence of a metastable biaxial state, and a phase diagram of the nematic texture has been built, therefore confirming the appropriateness of the used technique for the study of this type of problem.