Self-oscillating systems possess the ability to convert ambient energy directly into mechanical work, and new types of self-oscillating systems are worth designing for practical applications in energy harvesters, engines and actuators. Taking inspiration from the four-stroke engine. A concept for a …
[Phys. Rev. E 109, 034701] Published Mon Mar 04, 2024
]]>We report experimental investigations of a liquid crystal comprising thiophene-based achiral bent-core banana shaped molecules. The compound exhibits the following phase sequence on cooling: Isotropic (517.4 K), (514.9 K), de Vries SmA (402 K), SmC. Practically no layer contraction was observed ac…
[Phys. Rev. E 109, 024703] Published Mon Feb 26, 2024
]]>Twist-bend () and ferroelectric () nematic liquid crystals exhibit several novel effects and new physical properties. Here, we report experimental studies on the phase diagram and some physical properties of binary mixtures of CB9CB and RM734 mesogens. Both N- and N- phase transition tempe…
[Phys. Rev. E 109, 024702] Published Tue Feb 13, 2024
]]>Self-oscillating coupled systems possess the ability to actively absorb external environmental energy to sustain their motion. This quality endows them with autonomy and sustainability, making them have application value in the fields of synchronization and clustering, thereby furthering research an…
[Phys. Rev. E 109, 024701] Published Mon Feb 05, 2024
]]>The dynamics of quasi-two-dimensional coalescence of isotropic droplets in nematic liquid crystal environment was studied. Investigations were made in confined geometry of a Hele-Shaw optical cell with different transverse droplet sizes. The existence of three distinct dynamic regimes was found for …
[Phys. Rev. E 109, 014702] Published Fri Jan 26, 2024
]]>Volterra's definition of dislocations in crystals geometrically distinguishes edge and screw defects according to whether the Burgers vector is perpendicular or parallel to the defect. A homotopy-theoretic analysis of dislocations as topological defects fails to differentiate edge and screw. Here we…
[Phys. Rev. E 109, L012701] Published Wed Jan 24, 2024
]]>Only a few years have passed since the discovery of polar nematics, and now they are becoming the most actively studied liquid-crystal materials. Despite numerous breakthrough findings made recently, a theoretical systematization is still lacking. In the present paper, we take a step toward systemat…
[Phys. Rev. E 109, 014701] Published Thu Jan 18, 2024
]]>Chromonic nematics are lyotropic liquid crystals that have already been known for half a century, but have only recently raised interest for their potential applications in life sciences. Determining elastic constants and anchoring strengths for rigid substrates has thus become a priority in the cha…
[Phys. Rev. E 108, 064701] Published Wed Dec 27, 2023
]]>Using a linear hydrodynamic theory, we demonstrate that Faraday waves occur in liquid crystalline fluids. The use of already experimentally known material parameters of a -(4-methoxybenzylidene)-4-butylaniline liquid crystal allows us to confirm and realize the predictions of this theory. It provid…
[Phys. Rev. E 108, 054703] Published Wed Nov 22, 2023
]]>Light sources that switch periodically over time have a wide range of application value in life and engineering, and generally require additional controller to periodically switch circuits to achieve periodic lighting. In this paper, a self-oscillating spring oscillator based on optically responsive…
[Phys. Rev. E 108, 054702] Published Fri Nov 17, 2023
]]>The main objective of this work is to clarify the role that taper-shaped elongated molecules, i.e., molecules with one end wider than the other, can play in stabilizing orientational order. The focus is exclusively on entropy-driven self-organization induced by purely excluded volume interactions. D…
[Phys. Rev. E 108, 054701] Published Thu Nov 09, 2023
]]>Electrically driven kinklike distortion regimes in a microsized liquid crystal channel have been investigated both experimentally and analytically. Kinklike distortion waves were excited by the interaction between the electric field and the gradient of the director field in a homogeneously ali…
[Phys. Rev. E 108, 034703] Published Wed Sep 27, 2023
]]>The properties of composites of mesogens and two-dimensional (2D) materials are of great interest due to their practical applications in flexible displays, optoelectronics, microelectronics, and novel nanodevices. The properties of such composites are very complex and strongly depend on the interact…
[Phys. Rev. E 108, 034702] Published Tue Sep 12, 2023
]]>We report the effect on the phase transitional behavior of 8OCB liquid crystal (LC) doped with functionalized CdSe/ZnS quantum dots (QDs) in different concentrations. The temperature-dependent data of high-resolution optical birefringence and dielectric anisotropy are utilized to characterize the cr…
[Phys. Rev. E 108, 034701] Published Mon Sep 11, 2023
]]>We study pairwise interactions between localized topological structures in chiral magnetic and cholesteric liquid crystal (CLC) systems confined in the planar geometry. Our calculations for magnetics are based on the lattice model that takes into account the bulk and surface anisotropies along with …
[Phys. Rev. E 108, 024705] Published Thu Aug 31, 2023
]]>We study the director configurations of nematic liquid crystal (NLC) droplets with homeotropic anchoring in a magnetic field and report observation of a magnetic-field-driven transition from a deformed radial to an axial-with-defect configuration. Magnetic-field-induced transitions in NLC droplets d…
[Phys. Rev. E 108, 024704] Published Mon Aug 21, 2023
]]>We investigated the properties of cholesteric liquid crystals (CLCs) being in an external static magnetic field directed along the helix axis. We considered a dichroic CLC, that is, CLC with parameters and , where are the principal values of the local dielectric…
[Phys. Rev. E 108, 024703] Published Tue Aug 15, 2023
]]>Proton-decoupled deuterium NMR spectra were obtained for an asymmetric liquid crystal dimer 1-(4-cyanobiphenyl-4′-yloxy)-6-(4-cyanobiphenyl-4′-yl)hexane (CB6OCB) containing a single -- group. The sample has two nematic liquid crystal phases: a twist-bend nematic, , at the lowest temperature fo…
[Phys. Rev. E 108, 024702] Published Mon Aug 14, 2023
]]>An amalgam of nematic liquid crystals and active matter, referred to as living liquid crystals, is a promising self-healing material with futuristic applications for targeted delivery of information and microcargo. We provide a phenomenological model to study the symbiotic pattern dynamics in this c…
[Phys. Rev. E 108, 024701] Published Wed Aug 02, 2023
]]>The stability conditions of twist-bend nematics given by Barbero et al. [Phys. Rev. E 92, 030501(R) (2015)] lead to doubtful conclusions when the influence of the magnetic field on the structure is analyzed. For this reason, the stability criteria have been redetermined in the present paper. The…
[Phys. Rev. E 108, 014701] Published Mon Jul 31, 2023
]]>The present study investigates the arrangement of hollow pyramidal cone shells and their interactions with degenerate planar anchoring on the inner and outer surfaces of particles within the nematic host. The shell thickness is in order of the nematic coherence length. The numerical behavior of coll…
[Phys. Rev. E 107, 064703] Published Thu Jun 22, 2023
]]>Not every particle that forms a nematic liquid crystal makes a smectic. The particle tip is critical for this behavior. Ellipsoids do not make a smectic, but spherocylinders do. Similarly, only those -CB alkylcyanobiphenyls with sufficiently long ( carbons) alkane tails form smectics. We underst…
[Phys. Rev. E 107, 064702] Published Tue Jun 20, 2023
]]>The response to an applied electric field in the subphase of the MC881-MC452 binary mixture system is studied by using thick homeotropically aligned cells. In the ordinary antiferroelectric and 1/2 (sub)phases, some nonplanar asymmetric distortions in the antiferroelectric unit cell str…
[Phys. Rev. E 107, 064701] Published Thu Jun 01, 2023
]]>We present a detailed analysis of -director anchoring measurements on simple edge dislocations at the surface of smectic- films (steps). Indications show that the -director anchoring on the dislocations originates from a local and partial melting of the dislocation core that depends on the ancho…
[Phys. Rev. E 107, 054702] Published Mon May 22, 2023
]]>We propose an approach combining the continuum theory and molecular-statistical approach for a suspension of carbon nanotubes based on a negative diamagnetic anisotropy liquid crystal. Using the continuum theory, we show that in the case of an infinite sample in suspension it is possible to observe …
[Phys. Rev. E 107, 054701] Published Wed May 17, 2023
]]>The mesogen 1,′′7′′-bis(4-cyanobiphenyl-4′-yl)heptane (CB7CB), doped with a small quantity of an amphiphilic compound, is examined in its biphasic state in which twist-bend nematic () drops are dispersed in the isotropic fluid. Various flexoelectric and electrokinetic responses of small drops in …
[Phys. Rev. E 107, 044703] Published Fri Apr 28, 2023
]]>For recent applications, liquid crystal-carbon nanotube based nanocomposite systems have been proven to be highly attractive. In this paper, we give a thorough analysis of a nanocomposite system made of both functionalized and nonfunctionalized multiwalled carbon nanotubes that are disseminated in a…
[Phys. Rev. E 107, 044704] Published Fri Apr 28, 2023
]]>This paper complements a previous study of the isotropic and nematic phases of the Gay-Berne liquid-crystal model [Mehri et al., Phys. Rev. E 105, 064703 (2022)] with a study of its smectic- phase found at high density and low temperatures. We find also in this phase strong correlations between th…
[Phys. Rev. E 107, 044702] Published Thu Apr 27, 2023
]]>After quenching, a liquid crystal film might contain thousands of topological defects which annihilate during coarsening. The authors analyze high-speed video of the coarsening process using neural networks, and find agreement with theoretical predictions and simulations.
[Phys. Rev. E 107, 044701] Published Mon Apr 03, 2023
]]>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 state…
[Phys. Rev. E 107, 034707] Published Thu Mar 30, 2023
]]>The mesogen CB7CB [1″,7″-bis(4-cyanobiphenyl-4′-yl)heptane], mixed with a small quantity of a long chain amphiphile, is examined for the structural features of twist-bend nematic drops acting as colloidal inclusions in the isotropic and nematic environments. In the isotropic phase, the drops n…
[Phys. Rev. E 107, 034706] Published Tue Mar 28, 2023
]]>On the basis of Landau–de Gennes theory and the finite-difference iterative method, the autonomic modulation of chiral inversion in a cylindrical cavity with degenerate planar anchoring is investigated. Under the applied helical twisting power (inversely related to the pitch ), a chiral inversion c…
[Phys. Rev. E 107, 034705] Published Mon Mar 27, 2023
]]>Bent-Core banana-shaped molecules exhibit tilted polar smectic phases with macroscopically chiral layer order even though the constituent molecules are achiral in nature. Here, we show that the excluded volume interactions between the bent-core molecules account for this spontaneous breaking of chir…
[Phys. Rev. E 107, 034704] Published Fri Mar 24, 2023
]]>Density functional theory (DFT) calculations and x-ray diffraction techniques were employed to evaluate the value of the tilt angle in ferroelectric smectic and antiferroelectric smectic phases. Five homologues from the chiral series denoted as , based on 4-(1-methylhepty…
[Phys. Rev. E 107, 034703] Published Fri Mar 17, 2023
]]>A theoretical investigation of weak-anchoring effects in a thin two-dimensional pinned static ridge of nematic liquid crystal resting on a flat solid substrate in an atmosphere of passive gas is performed. Specifically, we solve a reduced version of the general system of governing equations recently…
[Phys. Rev. E 107, 034702] Published Thu Mar 16, 2023
]]>Self-assembly of colloidal particles into predefined structures is a promising way to design inexpensive manmade materials with advanced macroscopic properties. Doping of nematic liquid crystals (LCs) with nanoparticles has a series of advantages in addressing these grand scientific and engineering …
[Phys. Rev. E 107, 034701] Published Tue Mar 07, 2023
]]>The free-ion concentration in a nematic liquid crystal (LC) is found to be significantly reduced when gold nano-urchins (AuNUs) of 50-nm diameter are dispersed in the LC in dilute concentrations. The nano-urchins on AuNUs trap a significant amount of mobile ions, reducing the free-ion concentration …
[Phys. Rev. E 107, 024705] Published Mon Feb 27, 2023
]]>Authors of previous studies have focused on wrinkling phenomena in thin films with relatively large stiffness under mechanical loadings. A liquid crystal elastomer (LCE) is a smart soft material sensitive to various environmental stimuli. In this letter, we investigate the wrinkling instability of a…
[Phys. Rev. E 107, L022701] Published Thu Feb 23, 2023
]]>When particles are made to flow through a chiral liquid crystal phase, they can induce flows in the liquid crystal and as well as a rotation of the director. This paper describes experiments with a flux of ethanol through a chiral smectic-C* film, and gives an interpretation of the results in the context of the Leslie theory.
[Phys. Rev. E 107, 024703] Published Wed Feb 22, 2023
]]>Ethanol flowing through a chiral smectic-C* film can produce roughly circular patterns, but under different conditions also spiral patterns. Further experiments show these patterns, and their theoretical explanation is confirmed.
[Phys. Rev. E 107, 024704] Published Wed Feb 22, 2023
]]>Within the entire mesomorphic range, high-precision dielectric anisotropy data with the high-temperature resolution is presented for a highly polar smectic- liquid crystal 8CB (octylcyanobiphenyl) as well as 8CB nanocomposites doped with both pristine multi-walled carbon nanotubes (p-MWCNTs) and ca…
[Phys. Rev. E 107, 024702] Published Tue Feb 14, 2023
]]>In equilibrium hard-rod fluids, and in effective hard-rod descriptions of anisotropic soft-particle systems, the transition from the isotropic (I) phase to the nematic phase (N) is observed above the rod aspect ratio as predicted by Onsager. We examine the fate of this criterion in a molecu…
[Phys. Rev. E 107, 024701] Published Mon Feb 06, 2023
]]>The buckling transition of smectic liquid crystals (LCs) is important not only as fundamental physics but also for the rational design of devices to make use of their optical and mechanical properties. However, there exists a huge gap between the specific knowledge and universal analytical formulati…
[Phys. Rev. E 107, 014703] Published Tue Jan 31, 2023
]]>The reflection spectrum of linearly polarized light by a system consisting of a metal film and two adjacent sequentially located cholesteric liquid crystals (CLCs) with opposite helical twists is theoretically studied. The system contains a dielectric index-matching layer (DIML) between the metal fi…
[Phys. Rev. E 107, 014702] Published Mon Jan 30, 2023
]]>High-resolution calorimetry has played a significant role in providing detailed information on phase transitions in liquid crystals. In particular, adiabatic scanning calorimetry (ASC), capable of providing simultaneous information on the temperature dependence of the specific enthalpy and on t…
[Phys. Rev. E 107, 014701] Published Thu Jan 12, 2023
]]>We identified three types of flow in a nematic liquid crystal parallelepiped cell subjected to an ac electric field at low frequency. Our observations show the existence of translational flow, backflow, and convection flow in parallelepiped cells. We measured the backflow velocity by introducing mic…
[Phys. Rev. E 106, 064702] Published Thu Dec 22, 2022
]]>Twist-coupled elastic deformations are ubiquitous and in the limelight of interest for next-generation self-shaping materials. Here, we describe how twist dynamics under fixed anchoring lead to bend deformation and defect dynamics in a field-unwound chiral liquid crystal material. We use the Q-tenso…
[Phys. Rev. E 106, 064701] Published Tue Dec 20, 2022
]]>The purpose of this article is to describe the physical mechanism responsible for the appearance of both traveling and nontraveling distortions in a microsized homogeneously aligned nematic (HAN) film under the effect of a large electric field. Numerical studies have been carried out to describe bot…
[Phys. Rev. E 106, 054703] Published Wed Nov 23, 2022
]]>We have performed dielectric spectroscopy and thermally stimulated-depolarization-current experiments to study the molecular dynamics of the twist-bend nematic phase close to the glass transition of two members of the 1″,7′-bis(4-cyanobiphenyl-4′-yl)alkane homologous series (): the liquid cryst…
[Phys. Rev. E 106, 054702] Published Mon Nov 21, 2022
]]>A hydrogel which spontaneously swells in an aqueous polymer solution was observed to produce a new hydrogel film coated on its swollen surface. Here, inspired by this phenomenon, we theoretically formulate the dynamics of isotropic-to-nematic () phase transition caused by swelling a hydrogel subs…
[Phys. Rev. E 106, 054701] Published Fri Nov 18, 2022
]]>Topological defects are increasingly being identified in various biological systems, where their characteristic flow fields and stress patterns are associated with continuous active stress generation by biological entities. Here, using numerical simulations of continuum fluctuating nematohydrodynami…
[Phys. Rev. E 106, 044706] Published Fri Oct 28, 2022
]]>Elementary cellular automata provide one of the simplest ways to generally describe the phenomena of pattern formation. However, they are considered too simple to be able to describe in detail the more complex phenomena occurring in real experimental systems. In this article, we demonstrate the an a…
[Phys. Rev. E 106, 044705] Published Tue Oct 25, 2022
]]>Molecular interactions between liquid crystals (LCs) and reactive mesogens (RMs) at temperatures across the phase transition regions were comprehensively studied during photopolymerization-induced phase separation (PPIPS) beginning with raw mixtures until the formation of polymer network liquid crys…
[Phys. Rev. E 106, 044704] Published Thu Oct 20, 2022
]]>We describe investigations on the influence of the flexible spacer parity and length of the guest photoactive liquid-crystalline dimers in guest-host mixtures exhibiting photoinduced transitions involving isotropic (), cholesteric (), and twist grain boundary smectic- (TGB) phases. Despite a …
[Phys. Rev. E 106, 044702] Published Mon Oct 17, 2022
]]>Chromonic liquid crystals constitute a novel lyotropic phase, whose elastic properties have so far been modeled within the classical Oseen-Frank theory, provided that the twist constant is assumed to be considerably smaller than the saddle-splay constant, in violation of one Ericksen inequality. Thi…
[Phys. Rev. E 106, 044703] Published Mon Oct 17, 2022
]]>The biaxial phase in nematic liquid crystals has been elusive for several decades after its prediction in the 1970s. A recent experimental breakthrough was achieved by Liu et al. [Proc. Natl. Acad. Sci. USA 113, 10479 (2016)] in a liquid-crystalline medium with magnetic nanoparticles. They exploited…
[Phys. Rev. E 106, 044701] Published Fri Oct 14, 2022
]]>One of the unusual liquid crystalline phases exhibited by some compounds with bent-core (BC) molecules is designated as , in which transverse polarization (P) of smectic layers with upright molecules has a random orientational distribution. Most of such compounds undergo a transition to the
[Phys. Rev. E 106, 034702] Published Mon Sep 12, 2022
]]>Specific features of two-dimensional nematodynamics give rise to shortfalls of the tensor representation of the nematic order parameter commonly used in computations, especially in theory of active matter. The alternative representation in terms of the vector order parameter follows with small adjus…
[Phys. Rev. E 106, 034701] Published Tue Sep 06, 2022
]]>The paper presents a theoretical description of the light-induced nematic liquid crystal reorientation in a cell with gold nanoparticles deposited on the surface of one of bounding substrates. It is shown that the surface plasmon resonance in the nanoparticles significantly affects the threshold of …
[Phys. Rev. E 106, 024706] Published Thu Aug 18, 2022
]]>The structure of the nematic (cholesteric) drops that form at the clearing temperature of a mixture of the bent-core molecule CB7CB and the rodlike molecule 8CB doped with a surfactant is optically determined. Using experimental observations and numerical simulations, it is demonstrated that the dir…
[Phys. Rev. E 106, 024705] Published Tue Aug 16, 2022
]]>We investigate the ground-state configurations of two-dimensional liquid crystals with -fold rotational symmetry (-atics) on fixed curved surfaces. We focus on the intrinsic geometry and show that isothermal coordinates are particularly convenient as they explicitly encode a geometric contribution…
[Phys. Rev. E 106, 024704] Published Fri Aug 12, 2022
]]>The structural and magneto- and electro-optical properties of a self-organized ensemble of nematic domains formed on a polycarbonate film in the presence of a residual solvent are studied. The film covered one of the plane-parallel glass plates of a liquid crystal cell. The magnetic field stabilizin…
[Phys. Rev. E 106, 024703] Published Tue Aug 09, 2022
]]>We formulate a comprehensive hydrodynamic theory of two-dimensional liquid crystals with generic -fold rotational symmetry, also known as -atics, of which nematics and hexatics are the two best known examples. Previous hydrodynamic theories of -atics are characterized by continuous
[Phys. Rev. E 106, 024701] Published Fri Aug 05, 2022
]]>Unique electro-optical properties of the oblique helicoidal cholesteric () stem from its heliconical director structure. An applied electric field preserves the single-harmonic modulation of the director while tuning the period and the corresponding Bragg-peak wavelength within a broad spec…
[Phys. Rev. E 106, 024702] Published Thu Aug 04, 2022
]]>Living materials at different length scales manifest active nematic features such as orientational order, nematic topological defects, and active nematic turbulence. Using numerical simulations we investigate the impact of fluid inertia on the collective pattern formation in active nematics. We show…
[Phys. Rev. E 106, 014705] Published Mon Jul 25, 2022
]]>The presented study opens a perspective to investigate the effects of local flow on nematic liquid crystals. A particle rotated in nematic fluids typically generates a rotationally symmetric local flow, which causes a change in the director orientation. The director above the threshold velocity has …
[Phys. Rev. E 106, 014706] Published Mon Jul 25, 2022
]]>Focal conic structure formed near the transition from the cholesteric liquid crystal phase into isotropic liquid is studied in planar cells with a combination of optical methods. Employing a procedure with slow variation of temperature, we manage to obtain regions of periodic focal conic structure w…
[Phys. Rev. E 106, 014703] Published Wed Jul 13, 2022
]]>Twist-bend nematic liquid crystals ( LCs), although consisting of achiral molecules, possess a spontaneous conic helix. They have been intensively studied and utilized in many applications in recent years. Herein we add chiral molecules to LCs and study their effects on the structure of the c…
[Phys. Rev. E 106, 014704] Published Wed Jul 13, 2022
]]>A new scheme is investigated for evaluating the temperature dependence and dispersion relation of the Kerr constant () of an optically isotropic medium in isotropic and blue phases (BPs) liquid crystals. The scheme employs the measurement of the component of the transmitted light intensity of doubl…
[Phys. Rev. E 106, 014701] Published Fri Jul 01, 2022
]]>We report on phase transitions between isotropic and nematic liquid crystal phases in nonequilibrium systems (NESs). ac field-driven electroconvection (EC) provides an NES, which can be well controlled by the voltage and frequency ; it arises electrohydrodynamically at a threshold voltage . In …
[Phys. Rev. E 106, 014702] Published Fri Jul 01, 2022
]]>We use the Parsons-Lee modification of Onsager's second virial theory within the restricted orientation (Zwanzig) approximation to analyze the phase behavior of hard cylindrical rods confined in narrow pores. Depending on the wall-to-wall separation we predict a number of distinctly different surfac…
[Phys. Rev. E 105, 064704] Published Tue Jun 28, 2022
]]>This paper presents a numerical study of the Gay-Berne liquid crystal model with parameters corresponding to calamitic (rod-shaped) molecules. The focus is on the isotropic and nematic phases at temperatures above unity, where we find strong correlations between the virial and potential-energy therm…
[Phys. Rev. E 105, 064703] Published Thu Jun 23, 2022
]]>The purpose of this article is to describe the physical mechanism responsible for the appearance of both spatially periodic and kinklike distortions in a homogeneously aligned microsized nematic volume under the effect of crossed electric and magnetic fields. Numerical studies were carried out to de…
[Phys. Rev. E 105, 064702] Published Tue Jun 21, 2022
]]>We have elaborated a theoretical approach for the description of polar nematic phases observed by Nishikawa et al. [Adv. Mater. 29, 1702354 (2017)], their structures, and transitions between them. Specific symmetry contributions to the pair molecular potentials provide the molecular mechanisms respo…
[Phys. Rev. E 105, 064701] Published Fri Jun 03, 2022
]]>When liquid crystals are placed on the surface of a cone, the conical geometry generally leads to frustrated ground states. The authors study this system as a function of the cone angle and the liquid crystal symmetry, and find good agreement between theory and simulations.
[Phys. Rev. E 105, 054703] Published Tue May 31, 2022
]]>One of the simplest models that is used to study the isotropic-nematic tranition in liquid crystalline systems is the Lebwohl-Lasher model. Several extensions of this model further enhanced its applicability. We combine two of these extensions (a generalization and the inclusion of a chiral term) an…
[Phys. Rev. E 105, 054704] Published Tue May 31, 2022
]]>Systems with multistability are characterized by exhibiting complex nonlinear waves between equilibria. Experimentally, near the smectic- to chiral nematic transition in a liquid crystal mixture cell with planar anchoring, we observe finger fronts emerge in the smectic- phase when applying an elec…
[Phys. Rev. E 105, 054701] Published Tue May 17, 2022
]]>In the field of liquid crystals, it is well known that rodlike molecules interacting via long-range attractive interactions or short-range repulsive potentials can exhibit orientational order. In this work, we are interested in what would happen to systems of rodlike particles interacting via a long…
[Phys. Rev. E 105, 054702] Published Tue May 17, 2022
]]>A thermal gradient-induced circular motion of particles placed on ferroelectric nematic liquid crystal sessile drops is demonstrated and explained. Unlike hurricanes and tornadoes that are the prime examples for thermal motors and where turbulent flows are apparent, here the texture without tracer p…
[Phys. Rev. E 105, L052701] Published Fri May 06, 2022
]]>We investigate experimentally the formation of focal conic domains of the ferroelectric phase of a liquid crystal, chiral smectic (), in the meniscus geometry. The meniscus geometry is formed in the gap between two glass plates which are placed on a common substrate. This gap is called here a …
[Phys. Rev. E 105, 044706] Published Mon Apr 25, 2022
]]>We investigate numerically the structure of twin boundaries of cholesteric blue phases. Our study is based on the Landau–de Gennes continuum theory describing the orientational order of the liquid crystal by a second-rank tensor. We pay particular attention to blue phase I (BP I) with body-centered-…
[Phys. Rev. E 105, 044707] Published Mon Apr 25, 2022
]]>We employ a lattice-gas extension of the Maier-Saupe model with discrete orientation states to study the phase behavior of a statistical model for biaxial nematogenic units in mean-field theory. The phase behavior of the system is investigated in terms of the strength of isotropic interaction betwee…
[Phys. Rev. E 105, 044705] Published Wed Apr 20, 2022
]]>A two-dimensional or quasi-two-dimensional nematic liquid crystal refers to a surface-confined system. When such a system is further confined by external line boundaries or excluded from internal line boundaries, the nematic directors form a deformed texture that may display defect points or defect …
[Phys. Rev. E 105, 044704] Published Fri Apr 15, 2022
]]>An analysis of the IR absorbance for the segmented functional groups of liquid crystal dimers mesogen and linker enabled the orientation order to be determined and information about the dipole interactions in the nematic and twist-bend nematic phases to be obtained. The long axis orientational order…
[Phys. Rev. E 105, 044701] Published Tue Apr 05, 2022
]]>We report the discovery and elucidation of giant spatiotemporal orientational fluctuations in nematic liquid crystal drops with radial orientation of the nematic anisotropy axis producing a central “hedgehog” defect. We study the spatial and temporal properties of the fluctuations experimentally usi…
[Phys. Rev. E 105, 044702] Published Tue Apr 05, 2022
]]>We present calculations of eigenmode energies and wave functions of both azimuthal and polar distortions of the nematic director relative to a radial hedgehog trapped in a spherical drop with a smaller concentric spherical droplet at its core. All surfaces interior to the drop have perpendicular (ho…
[Phys. Rev. E 105, 044703] Published Tue Apr 05, 2022
]]>Egg cartons, known as doubly sinusoidal surfaces, display a rich variety of saddles-cylinder-spherical patches organized with different spatial symmetries and connectivities. Egg carton surfaces, rich in functionalities, are observed in synthetic and biological materials, as well as across atomic an…
[Phys. Rev. E 105, 034702] Published Wed Mar 23, 2022
]]>We theoretically study orientational structures in chiral magnetics and cholesteric liquid crystal (CLC) nanosystems confined in the slab geometry. Our analysis is based on the model that, in addition to the exchange and the Dzyaloshinskii-Moriya interactions, takes into account the bulk and surface…
[Phys. Rev. E 105, 034701] Published Mon Mar 21, 2022
]]>Binary mixtures of the mesogen [1″,7″-bis(4-cyanobiphenyl-4′-yl)heptane] and a long chain amphiphile (e.g., 2-octadecoxypropanol) are examined for the structure, stability, and electro-optical behavior of nematic drops dispersed in the isotropic phase, in planar cells. Subjected to tangential bounda…
[Phys. Rev. E 105, 024709] Published Mon Feb 28, 2022
]]>Recent theoretical research has developed a general framework to understand director deformations and modulated phases in nematic liquid crystals. In this framework, there are four fundamental director deformation modes: twist, bend, splay, and a fourth mode related to saddle-splay. The first thre…
[Phys. Rev. E 105, 024708] Published Fri Feb 25, 2022
]]>We show experimentally and theoretically that the heliconical fluctuations that develop in a cholesteric phase (Ch) close to a transition to a chiral twist-bend nematic phase may lead to the appearance of a compensation point. At this point, the equilibrium twist of the cholesteric phase vanis…
[Phys. Rev. E 105, 024707] Published Thu Feb 24, 2022
]]>The anisotropic shape of calamitic liquid crystal (LC) particles results in distinct values of energy when the nematogens are placed side by side or end to end. This anisotropy in energy which is governed by a parameter has deep consequences on equilibrium and nonequilibrium properties. Using the…
[Phys. Rev. E 105, 024706] Published Wed Feb 23, 2022
]]>Vitrification of the antiferroelectric smectic- phase is reported for the orthoconic mixture W-1000 and its new derivative W-356. The crystallization is not observed even upon slow cooling and the cold crystallization on subsequent heating is also absent. Molecular dynamics in the smectic phases …
[Phys. Rev. E 105, 024705] Published Tue Feb 22, 2022
]]>The author provides experimental evidence of the onset of a heliconical phase when a cholesteric liquid crystal is confined between two parallel plates with specific anchoring conditions. The confinement unwinds the cholesteric phase and plays a similar role as the electric field in previous experiments. The article also presents a theoretical treatment to explain the experimental observations.
[Phys. Rev. E 105, 024704] Published Fri Feb 18, 2022
]]>Using a grand-canonical Landau–de Gennes theory for colloidal suspensions of bent (banana-shaped) rods, we investigate how spatial deformations in the nematic director field affect the local density of twist-bend and splay-bend nematic phases. The grand-canonical character of the theory naturally re…
[Phys. Rev. E 105, L022701] Published Tue Feb 15, 2022
]]>Geometric frustration results from a discrepancy between the locally favored arrangement of the constituents of a system and the geometry of the embedding space. Geometric frustration can be either noncumulative, which implies an extensive energy growth, or cumulative, which implies superextensive e…
[Phys. Rev. E 105, 024703] Published Wed Feb 09, 2022
]]>A method for electrically controlled synchronous mode tuning in the transmittance and reflectance spectra of a photonic structure consisting of an asymmetric dielectric Fabry-Pérot microcavity and an ultrathin metallic film has been proposed. The excitation of a broadband Tamm plasmon polariton at a…
[Phys. Rev. E 105, 024702] Published Tue Feb 08, 2022
]]>We analyze the interaction with uniform external fields of nematic liquid crystals within a recent generalized free energy posited by Virga and falling in the class of quartic functionals in the spatial gradients of the nematic director. We review some known interesting solutions, i.e., uniform heli…
[Phys. Rev. E 105, 024701] Published Mon Feb 07, 2022
]]>This work takes advantage of the nonmonotonic dependence of the surface tension of liquid crystals on temperature to study Marangoni flow in sandwich cells under controlled temperature. The authors find intricate behaviors depending on the phases of the material as well as on the anchoring conditions.
[Phys. Rev. E 105, L012701] Published Mon Jan 24, 2022
]]>Understanding the relaxation dynamics of colloidal suspensions is crucial to identifying the elements that influence the mobility of their constituents, assessing their macroscopic response across the relevant time and length scales, and thus disclosing the fundamentals underpinning their exploitati…
[Phys. Rev. E 105, 014703] Published Tue Jan 18, 2022
]]>