While twist-bend nematic phases have been extensively studied, the experimental observation of two dimensional, oscillating splay-bend phases is recent. We consider two theoretical models that have been used to explain the formation of twist-bend phases-flexoelectricity and bond orientational order-as mechanisms to induce splay-bend phases. Flexoelectricity is a viable mechanism, and splay and bend flexoelectric couplings can lead to splay-bend phases with different modulations. We show that while bond orientational order circumvents the need for higher order terms in the free energy, the important role of nematic symmetry and phase chirality rules it out as a basic mechanism.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevE.100.022704 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Non-nematicity of the filamentary phase in systems of hard minor circular arcs.
Phys Rev E
October 2024
Departamento de Física Teórica de la Materia Condensada, Instituto de Física de la Materia Condensada (IFIMAC), Instituto de Ciencias de Materiales "Nicolás Cabrera," Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain.
This work further investigates an aspect of the phase behavior of hard circular arcs whose phase diagram has been recently calculated by Monte Carlo numerical simulations: the non-nematicity of the filamentary phase that hard minor circular arcs form. Both second-virial density-functional theory and further Monte Carlo numerical simulations find that the positional one-particle density function undulates in the direction transverse to the axes of the filaments while further Monte Carlo numerical simulations find that the mobility of the hard minor circular arcs across the filaments occurs via a mechanism reminiscent of the mechanism of diffusion in a smectic phase: the filamentary phase is not a {"modulated" ["splay(-bend)"]} nematic phase.
View Article and Find Full Text PDFStructural parameters of twist-bend nematics and splay-bend nematics in Dozov's theory.
Phys Rev E
April 2024
Institute of Physics, Lodz University of Technology, ulica Wólczańska 217/221, 93-005 Łódź, Poland.
This paper presents the results of numerical calculations revealing how the structural parameters (i.e., the pitch p_{TB}, the spatial period p_{SB}, and the tilt angle θ_{TB} or θ_{SB}) of twist-bend nematics (N_{TB}) and splay-bend nematics (N_{SB}) depend on the values of elastic constants in Dozov's theory [I.
View Article and Find Full Text PDFConformational degrees of freedom and stability of splay-bend ordering in the limit of a very strong planar anchoring.
Phys Rev E
March 2023
Faculty of Materials Engineering and Physics, Cracow University of Technology, ul. Podchorążych 1, 30-084, Kraków, Poland.
We study the self-organization in a monolayer (a two-dimensional system) of flexible planar trimer particles. The molecules are made up of two mesogenic units linked by a spacer, all of which are modeled as hard needles of the same length. Each molecule can dynamically adopt two conformational states: an achiral bent-shaped (cis-) and a chiral zigzag (trans-) one.
View Article and Find Full Text PDFTheoretical models of modulated nematic phases.
Soft Matter
April 2023
Institute of Physics, Lodz University of Technology, Łódź, Poland.
Novel modulated nematic phases, such as twist-bend nematics, splay-bend nematics and splay nematics, are an important subject of research in the field of liquid crystals. In this article fundamental information about the discovery, structure and properties of these phases is presented. Various theoretical models of elastic properties are compared, especially the proposed formulae for the free energy density of modulated nematic phases and the conditions for their stability.
View Article and Find Full Text PDFSplay-bend nematic phases of bent colloidal silica rods induced by polydispersity.
Nat Commun
December 2022
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC, Utrecht, The Netherlands.
Liquid crystal (LC) phases are in between solids and liquids with properties of both. Nematic LCs composed of rod-like molecules or particles exhibit long-range orientational order, yielding characteristic birefringence, but they lack positional order, allowing them to flow like a liquid. This combination of properties as well as their sensitivity to external fields make nematic LCs fundamental for optical applications e.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!