2020/11/04 by Semen S. Tenishchev, Ivan M. Tambovtcev, Tenishchev, Semen S. +5
Chemistry · Computer Science · Materials Science · #FOS: Physical sciences #Liquid Crystal Research Advancements #Molecular spectroscopy and chirality #Nonlinear Dynamics and Pattern Formation #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2011.02401
openalex publication_date 2020/11/04 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
We study minimum-energy pathways (MEPs) between the branches of metastable\nhelical structures in chiral nematic liquid crystals (CNLCs)subjected to the\nelectric field applied across the cell. By performing stability analysis we\nhave found that, for the branches with non-vanishing half-turn number, the\nthreshold (critical) voltage of the Freedericksz transition is an increasing\nfunction of the free twisting wave number. The curves for the threshold voltage\ndepend on the elastic anisotropy and determine the zero-field critical free\ntwisting number where the director out-of-plane fluctuations destabilize the\nCNLC helix. For each MEP passing through a first order saddle point we have\ncomputed the energy barrier as the energy difference between the saddle-point\nand the initial structures at different values of the applied field. In our\ncalculations, where the initial approximation for a MEP at the next step was\ndetermined by the MEP obtained at the previous step, the electric field\ndependence of the energy barrier is found to exhibit the hysteresis. This is\nthe hysteresis of electrically driven transition of the saddle-point\nconfiguration between the planar and the tilted structures involving\nout-of-plane director deformations. It turned out that, by contrast to the\nsecond-order Freedericksz transition, this transition is first order and we\nhave studied how it depends on the zenithal anchoring energy strength.\n