The minimal ingredient to generate a biaxial liquid-crystalline order is usually considered to be a strong biaxiality either in the molecular shape or in the molecular interactions. Although there is no fundamental reason to forbid a spontaneous biaxial liquid-crystalline ordering of pure uniaxial o...

[Phys. Rev. E 98, 050701(R)] Published Tue Nov 27, 2018

]]>Short pitch deformed helix ferroelectric liquid crystals have numerous applications as active materials in displays, optical telemetry, and biomedical devices. In this paper, we derive convenient analytical formulas to calculate the effective dielectric tensor of these materials beyond the space ave...

[Phys. Rev. E 98, 052707] Published Tue Nov 27, 2018

]]>The critical behavior at the transition from a uniform nematic to a twist-bend modulated nematic phase is revealed and shown to be well explained by the mean field approximation. The study was performed on a group of materials that exhibit an unusually broad temperature range of the nematic phase ab...

[Phys. Rev. E 98, 052706] Published Mon Nov 26, 2018

]]>Optical investigations and calculation of structures were performed on films of liquid crystal with the sequence of phase transitions in the bulk sample $\mathrm{Sm}{C}_{A}^{*}-\mathrm{Sm}{C}_{d3}^{*}-\mathrm{Sm}{C}_{d4}^{*}-\mathrm{Sm}{C}^{*}-\mathrm{Sm}{C}_{\alpha}^{*}-\mathrm{Sm}A-I$. We investigated freestanding nanofilms with number of smectic layers from 2 to 6 with thickness commensurate,...

[Phys. Rev. E 98, 052705] Published Tue Nov 20, 2018

]]>We study electrohydrodynamic convection (EHC) patterns in twisted nematic liquid crystal (TNCL) cells with an initial homeotropic alignment. In addition, we demonstrate switching characteristics due to the transition between the 90° and $-{90}^{\circ}$ twisted states. The pattern formations are similar to thos...

[Phys. Rev. E 98, 052704] Published Mon Nov 19, 2018

]]>Experimental and theoretical studies of a smectic-$A$–hexatic-$B$ transition in freely suspended films of thickness $2\u201310\phantom{\rule{3.33333pt}{0ex}}\mu \mathrm{m}$ of the $n$-pentyl-${4}^{\prime}-n$-pentanoyloxy-biphenyl-4-carboxylate (54COOBC) compound are presented. X-ray investigations revealed a discontinuous first-order transition into the hexatic phas...

[Phys. Rev. E 98, 052703] Published Fri Nov 16, 2018

]]>We use density functional theory to explore the stable adsorption geometries of the liquid crystal molecule 5CB on a graphene sheet. First, we calculate the dependence of the polarizability of 5CB on its geometry. Our results break down the contributions of the cyano, biphenyl, and alkyl groups to t...

[Phys. Rev. E 98, 052702] Published Tue Nov 06, 2018

]]>Azobenzene-based molecular systems are used as photoreswitchable smart materials with applications in many areas, including designing surface orientational patterning of anisotropic molecules. It is important and challenging to probe the real-time photoresponsive behaviors of these systems, particul...

[Phys. Rev. E 98, 052701] Published Fri Nov 02, 2018

]]>To inquire into whether two enantiomers can be absolutely distinguished on the sole basis of their different degrees of orientational ordering when dissolved in a chiral nematic liquid crystal, several enantiomeric pairs of hard helical particles are dissolved in a cholesteric (nematic) liquid cryst...

[Phys. Rev. E 98, 042704] Published Tue Oct 30, 2018

]]>We consider the influence of tetrahedral (octupolar) order on ferromagnetic nematic liquid-crystalline phases. The presence of tetrahedral order leads to broken parity symmetry in an achiral liquid-crystalline system, in addition to broken time-reversal symmetry associated with the existence of a sp...

[Phys. Rev. E 98, 042703] Published Thu Oct 25, 2018

]]>We study the light scattering by localized quasiplanar excitations of a cholesteric liquid crystal known as spherulites. We quantitatively evaluate the cross section of the axis rotation for polarized light by taking into account the anisotropic optical properties of the medium and the peculiar shap...

[Phys. Rev. E 98, 042702] Published Thu Oct 18, 2018

]]>Sunset Yellow (SSY) is an aromatic heterocycle nano-sheet functionalized by hydrophilic sulphanate groups. SSY forms chromonic stacks and liquid crystal (LC) phases in aqueous solution. The DNA oligomer 5′-GCGCTTAAGCGC-3′ is a self-complementary strand which forms duplexed B-form helices in aqueous ...

[Phys. Rev. E 98, 042701] Published Mon Oct 08, 2018

]]>A large number of smectic phases can have the same energy when short-range interlayer interactions (interaction of nearest layers and frustrating next-nearest layer interaction) are taken into account. In this situation even weak long-range interactions become important. They lift the degeneracy and...

[Phys. Rev. E 98, 032707] Published Fri Sep 28, 2018

]]>This article provides an explanation for the instability of toric focal conic domains and the stability of parabolic focal conic domains in the twist-bend nematic (${N}_{\mathrm{TB}}$) phase, by reason of the presence (the first case) or absence (the second case) of defect densities attached to the conics, which ar...

[Phys. Rev. E 98, 032705] Published Mon Sep 24, 2018

]]>Topological defects resulting from boundary constraints in confined liquid crystals have attracted extensive research interest. In this paper, we use numerical simulation to study the phase transition dynamics in the context of stochastic resonance in a bistable liquid crystal device containing defe...

[Phys. Rev. E 98, 032706] Published Mon Sep 24, 2018

]]>The Lehmann effect is the rotation of cholesteric droplets when they are submitted to a temperature gradient. So far, this effect was only observed in the coexistence region between the cholesteric phase and its isotropic liquid. This zone of coexistence is due to the presence in the LC of impuritie...

[Phys. Rev. E 98, 032704] Published Wed Sep 19, 2018

]]>The phase behavior of hard rectangular rods with edge lengths $L$, $D$, and $D$ is studied in a narrow slitlike pore using the Parsons-Lee density functional theory. Using the restricted orientation approximation, we find strong adsorption at the walls with planar ordering, second order uniaxial-biaxial o...

[Phys. Rev. E 98, 032703] Published Fri Sep 07, 2018

]]>We investigate flexodomains, which are observed in planar layers of certain nematic liquid crystals, when a dc voltage $U$ above a critical value ${U}_{c}$ is applied across the layer. They are characterized by stationary stripelike spatial variations of the director in the layer plane with a wave number $p(U...$

[Phys. Rev. E 98, 032702] Published Wed Sep 05, 2018

]]>In this study, we numerically investigate the interactions between pentagonal truncated pyramids in a nematic liquid crystal host. The colloidal arrangements are investigated by minimizing the Landau-de Gennes free energy in presence of homeotropic anchoring surface energy upon the particles. We fur...

[Phys. Rev. E 98, 032701] Published Tue Sep 04, 2018

]]>The dielectric spectra of the twist bend nematic phase (${N}_{\mathrm{TB}}$) of an achiral asymmetric bent-core liquid crystalline compound are studied for determining the various relaxation modes. Dielectric measurements are also carried out under the bias field $E$ up to 8 V/µm. Two molecular and two collective rel...

[Phys. Rev. E 98, 022704] Published Fri Aug 31, 2018

]]>Electrokinetic phenomena in a nematic suspension are considered when one or more dielectric particles are suspended in a liquid crystal matrix in its nematic phase. The long-range orientational order of the nematic constitutes a fluid with anisotropic properties. This anisotropy enables charge separ...

[Phys. Rev. E 98, 022703] Published Thu Aug 23, 2018

]]>In the present work, we have studied the liquid crystalline properties of a luminescent molecule, which presents smectic mesophases, using the emission ellipsometry technique. A methodology with photoselection of the excitation light to improve the experiment is presented. An empirical model is prop...

[Phys. Rev. E 98, 022702] Published Fri Aug 10, 2018

]]>A rigorous microscopic treatment of a nematic fluid system based on a pairwise interaction potential is immensely complex. For studying such systems molecular field theories are often the standard method of choice. In this paper we have chosen a simple effective potential $U=\frac{{u}_{4}}{{v}^{4}}-\frac{{u}_{2}}{{v}^{2}}-\frac{A{u}_{2}}{{v}^{2}}\u2329{P}_{2}\u232a{P}_{2}(cos\vartheta )$...

[Phys. Rev. E 98, 022701] Published Wed Aug 01, 2018

]]>Electric field driven Frèedericksz transition in chiral nematic (cholesteric) planar liquid crystal cell is studied in the presence of flexoelectric effect. An inhomogeneity of electric field and finiteness of anchoring energy are considered. The extra contribution to the electric field induced by f...

[Phys. Rev. E 98, 012702] Published Mon Jul 23, 2018

]]>When a material surface is functionalized so as to acquire some type of order, functionalization of which soft condensed matter systems have recently provided many interesting examples, the modeler faces an alternative. Either the order is described on the curved, physical surface where it belongs, ...

[Phys. Rev. E 98, 012701] Published Fri Jul 20, 2018

]]>An anomalous dielectric relaxation process, called the partially unwound helical mode (*p-*UHM), is a collective dielectric process apart from the well known Goldstone and soft mode process; it is studied in the smectic ${C}^{*}$ ($\mathrm{Sm}\text{\u2212}{C}^{*}$) phase and at the transition temperature of the $\mathrm{Sm}\text{\u2212}{C}^{*}-\mathrm{Sm}\text{\u2212}{A}^{*}$ phase in the...

[Phys. Rev. E 97, 062707] Published Wed Jun 27, 2018

]]>When chiral liquid crystals or magnets are subjected to applied fields or other anisotropic environments, the competition between favored twist and anisotropy leads to the formation of complex defect structures. In some cases, the defects are skyrmions, which have ${180}^{\circ}$ double twist going outward fro...

[Phys. Rev. E 97, 062706] Published Wed Jun 20, 2018

]]>We consider the reshaping of closed Janus filaments acquiring intrinsic curvature upon actuation of a driven component—a nematic elastomer elongating upon phase transition. Linear stability analysis establishes instability thresholds of circles with no imposed twist, dependent on the ratio $q$ of the ...

[Phys. Rev. E 97, 062705] Published Mon Jun 18, 2018

]]>We modeled the experimentally observed self-assembly of nanoparticles (NPs) into shells with diameters up to 10 $\mu \mathrm{m}$, via segregation from growing nematic domains. Using field-based Monte Carlo simulations, we found the equilibrium configurations of the system by minimizing a free-energy functional th...

[Phys. Rev. E 97, 062704] Published Fri Jun 15, 2018

]]>The self-propelled motions of micron-sized nematic liquid crystal droplets in an aqueous surfactant solution have been studied by tracking individual droplets over long time periods. Switching between self-propelled modes is observed as the droplet size decreases at a nearly constant dissolution rat...

[Phys. Rev. E 97, 062703] Published Thu Jun 14, 2018

]]>Using resonant x-ray scattering techniques, transitional subphases during the electric-field-induced phase transition of a mixture of Se-containing chiral liquid crystals, 80% AS657 and 20% AS620, in a planar-aligned cell geometry were investigated, where the prototypical phase sequence $\mathrm{Sm}{C}_{A}^{*}-\mathrm{Sm}{C}_{\gamma}^{*}-\mathrm{...}$

[Phys. Rev. E 97, 062702] Published Tue Jun 12, 2018

]]>We develop a theoretical model to describe two-beam energy exchange in a hybrid photorefractive cholesteric cell with a short-pitch helix oriented parallel to the cell substrates (so-called uniformly lying helix configuration). Weak and strong light beams incident on the hybrid cell interfere and in...

[Phys. Rev. E 97, 062701] Published Fri Jun 01, 2018

]]>When a spatially uniform system that displays a liquid-crystal ordering on a two-dimensional surface is confined inside a rectangular box, the liquid crystal direction field develops inhomogeneous textures accompanied by topological defects because of the geometric frustrations. We show that the ric...

[Phys. Rev. E 97, 052707] Published Wed May 30, 2018

]]>Ordering configurations of a director field on a curved membrane induces stress. In this work, we present a theoretical framework to calculate the stress tensor and the torque as a consequence of the nematic ordering; we use the variational principle and invariance of the energy under Euclidean moti...

[Phys. Rev. E 97, 052706] Published Tue May 29, 2018

]]>Nematic films are thin fluid structures, ideally two dimensional, endowed with an in-plane degenerate nematic order. In this paper we examine a generalization of the classical Plateau problem to an axisymmetric nematic film bounded by two coaxial parallel rings. At equilibrium, the shape of the nema...

[Phys. Rev. E 97, 052705] Published Thu May 24, 2018

]]>Nematogenic liquids are materials that are in high demand for many application purposes. Field-induced nematic order in isotropic liquids can be observed by the enhancement of electric permittivity during dielectric spectroscopy measurements under the bias electric field. For this reason, dielectric...

[Phys. Rev. E 97, 052704] Published Fri May 18, 2018

]]>We formulate the scaled particle theory for a general mixture of hard isosceles triangles and calculate different phase diagrams for the one-component fluid and for certain binary mixtures. The fluid of hard triangles exhibits a complex phase behavior: (i) the presence of a triatic phase with sixfol...

[Phys. Rev. E 97, 052703] Published Fri May 11, 2018

]]>The hexatic phase predicted by the theories of two-dimensional melting is characterized by the power-law decay of the orientational correlations, whereas the in-layer bond orientational order in all the hexatic smectic phases observed so far was found to be long range. We report a hexatic smectic ph...

[Phys. Rev. E 97, 052702] Published Thu May 10, 2018

]]>Active colloids and liquid crystals are capable of locally converting the macroscopically supplied energy into directional motion and promise a host of new applications, ranging from drug delivery to cargo transport at the mesoscale. Here we uncover how topological solitons in liquid crystals can lo...

[Phys. Rev. E 97, 052701] Published Wed May 02, 2018

]]>We investigate the alternating current (ac) -driven electroconvection (EC) in one-dimensional cells (1DCs) under the in-plane switching mode. In 1DCs, defect-free EC can be realized. In the presence and absence of external multiplicative noise, the features of traveling waves (TWs), such as their Ho...

[Phys. Rev. E 97, 042707] Published Mon Apr 30, 2018

]]>A molecular field theory and coarse-grained computer simulations with dissipative particle dynamics have been used to study the spontaneous orientational ordering of anisotropic nanoparticles in the lamellar and hexagonal phases of diblock copolymers and the effect of nanoparticles on the phase beha...

[Phys. Rev. E 97, 042706] Published Fri Apr 27, 2018

]]>We investigate the effects of flow on the dynamics of ferromagnetic nematic liquid crystals. As a model, we study the coupled dynamics of the magnetization, $\mathbf{M}$, the director field, $\mathbf{n}$, associated with the liquid crystalline orientational order, and the velocity field, $\mathbf{v}$. We evaluate how simple shear f...

[Phys. Rev. E 97, 042705] Published Thu Apr 26, 2018

]]>Knotted fields enrich a variety of physical phenomena, ranging from fluid flows, electromagnetic fields, to textures of ordered media. Maxwell's electrostatic equations, whose vacuum solution is mathematically known as a harmonic field, provide an ideal setting to explore the role of domain topology...

[Phys. Rev. E 97, 040702(R)] Published Wed Apr 25, 2018

]]>Chiral smectic liquid crystals are known for their huge optical activity due to the precession of the anisotropic dielectric tensor around the helicoidal axis. For an oblique direction of the propagating wave, the helix acts as a grating which splits an incident beam in different directions as long ...

[Phys. Rev. E 97, 042704] Published Wed Apr 25, 2018

]]>We use experiment and computational modeling to understand the defect structure and director configuration in a nematic liquid crystal capillary bridge confined between two parallel plates. We find that tuning of the aspect ratio of the bridge drives a transition between a ring defect and a point de...

[Phys. Rev. E 97, 040701(R)] Published Fri Apr 13, 2018

]]>Tilted smectic liquid crystal phases such as the smectic-C phase seen in calamitic liquid crystals are usually treated using the assumption of biaxial orthorhombic symmetry. However, the smectic-C phase has monoclinic symmetry, thereby allowing disassociation of the principal optic and dielectric ax...

[Phys. Rev. E 97, 042702] Published Tue Apr 10, 2018

]]>A biaxial surface potential ${\mathrm{\Phi}}_{s}$ of smectic-${C}^{*}$ surface-stabilized ferroelectric liquid crystals (SSFLCs) is introduced in this paper to explain the experimentally observed electric-field dependence of polarization ${\stackrel{\u0303}{P}}_{\mathrm{cell}}\left(E\right)$, in particular the shape of the static hysteresis loops. Our potential consist...

[Phys. Rev. E 97, 042703] Published Tue Apr 10, 2018

]]>We study experimentally the impact of spherical nanoparticles on the orientational order parameters of a host nematic liquid crystal. We use spherical core-shell quantum dots that are surface functionalized to promote homeotropic anchoring on their interface with the liquid crystal host. We show exp...

[Phys. Rev. E 97, 042701] Published Fri Apr 06, 2018

]]>In thermotropic chiral $\mathrm{Sm}\text{\u2212}{A}^{*}$ phases, an electric field along the smectic layers breaks the ${D}_{\infty}$ symmetry of the $\mathrm{Sm}\text{\u2212}{A}^{*}$ phase and induces a tilt of the liquid crystal director. This so-called electroclinic effect (ECE) was first reported by Garoff and Meyer in 1977 and attracted substantial scientific a...

[Phys. Rev. E 97, 032705] Published Fri Mar 30, 2018

]]>The interaction between nematic liquid crystals and polymer-coated substrates may lead to slow reorientation of the easy axis (so-called “director gliding”) when a prolonged external field is applied. We consider the experimental evidence of zenithal gliding observed by Joly *et al.* [Phys. Rev. E **70**,...

[Phys. Rev. E 97, 032704] Published Mon Mar 19, 2018

]]>The competing effect of surface anchoring of dispersed microparticles and elasticity of nematic and cholesteric liquid crystals has been shown to stabilize a variety of topological defects. Here we study a pair of colloidal microparticles with homeotropic and planar surface anchoring across $N\text{\u2212}\mathrm{Sm}A\text{\u2212}\mathrm{Sm}\mathrm{...}$

[Phys. Rev. E 97, 032702] Published Tue Mar 13, 2018

]]>Coupling between the defect mode of a cholesteric liquid crystal and the localized mode of a cholesteric liquid crystal–phase plate–metal structure is theoretically demonstrated. It is shown that the transmittance spectrum can be tuned by changing the twist-defect angle and helix pitch, which are go...

[Phys. Rev. E 97, 032703] Published Tue Mar 13, 2018

]]>A micrometer-scale elastic shell immersed in a nematic liquid crystal may be deformed by the host if the cost of deformation is comparable to the cost of elastic deformation of the nematic. Moreover, such inclusions interact and form chains due to quadrupolar distortions induced in the host. A conti...

[Phys. Rev. E 97, 032701] Published Fri Mar 02, 2018

]]>In this work, the frequency dependence of the known mechano-optical effect which occurs in the micellar isotropic phases ($I$) of mixtures of potassium laurate (KL), decanol (DeOH), and water is investigated in the range from $200\phantom{\rule{4pt}{0ex}}\mathrm{mHz}$ to $200\phantom{\rule{4pt}{0ex}}\mathrm{Hz}$. In order to fit the experimental data, a model of superimpo...

[Phys. Rev. E 97, 022705] Published Thu Feb 22, 2018

]]>The electrical responses of a nematic liquid crystal sample confined between two cylindrical surfaces are investigated in the framework of elastic continuum theory. The responses are the result of the molecular reorientation induced by both the applied electric field and the cylindrical geometry of ...

[Phys. Rev. E 97, 022703] Published Tue Feb 20, 2018

]]>We present a framework for the study of disclinations in two-dimensional active nematic liquid crystals and topological defects in general. The order tensor formalism is used to calculate exact multiparticle solutions of the linearized static equations inside a planar uniformly aligned state so that...

[Phys. Rev. E 97, 022704] Published Tue Feb 20, 2018

]]>We consider a shallow rectangular well of nematic liquid crystal subject to weak anchoring on the sides of the well. By considering weak anchoring instead of infinitely strong anchoring, we are able to analyze nematic equilibria in the well without the need to exclude point defects at the corners, a...

[Phys. Rev. E 97, 022702] Published Fri Feb 16, 2018

]]>In this paper, we have investigated the behavior of mesogens at smectic-*C**–water interface confined in a liquid crystal (LC) cell with interfacial geometry. Polarized optical microscopy was used to probe the appearance of various smectic-*C** domain patterns at water interface owing to the reorientati...

[Phys. Rev. E 97, 022701] Published Fri Feb 09, 2018

]]>Recent studies on topological defects in conventional and active nematic liquid crystals have revealed their potential as sources of advanced functionality whereby the collective behavior of the constituent molecules or cells is controlled. On the other hand, the fact that they have high energies an...

[Phys. Rev. E 97, 020701(R)] Published Thu Feb 08, 2018

]]>Self-propelled elongated particles in two dimensions can form an active nematic phase. The authors show that this phase exhibits the same quasi-long-range order as equilibrium nematic and polar liquid crystals, but also find particular features such as strong finite-size effects and a nonuniversal exponent in the behavior of density fluctuations.

[Phys. Rev. E 97, 012707] Published Mon Jan 29, 2018

]]>Polyhedral nematics are examples of exotic orientational phases that possess a complex internal symmetry, representing highly nontrivial ways of rotational symmetry breaking, and are subject to current experimental pursuits in colloidal and molecular systems. The classification of these phases has b...

[Phys. Rev. E 97, 012706] Published Fri Jan 26, 2018

]]>We perform statistical mechanics calculations to analyze the global phase diagram of a fully connected version of a Maier-Saupe-Zwanzig lattice model with the inclusion of couplings to an elastic strain field. We point out the presence of uniaxial and biaxial nematic structures, depending on tempera...

[Phys. Rev. E 97, 012705] Published Mon Jan 22, 2018

]]>In the present work, a detailed analysis of the glassy behavior and the relaxation dynamics of the liquid crystal dimer α-(4-cyanobiphenyl-4′-yloxy)-ω-(1-pyrenimine-benzylidene-4′-oxy) heptane (CBO7O.Py) throughout both nematic and smectic-*A* mesophases by means of broadband dielectric spectroscopy h...

[Phys. Rev. E 97, 012704] Published Wed Jan 17, 2018

]]>The effect of strong confinement on the positional and orientational ordering is examined in a system of hard rectangular rods with length $L$ and diameter $D$ ($L>D$) using the Parsons-Lee modification of the second virial density-functional theory. The rods are nonmesogenic $(L/D<3)$ and confined be...

[Phys. Rev. E 97, 012703] Published Tue Jan 16, 2018

]]>Computer simulations are used to study the effect of confinement on the dynamics of active nematic liquid crystals. The authors find that active nematic systems, in contrast to passive systems, are rather insensitive to topological constraints. Topological charges required by container geometry are relegated to a small layer along the boundary, creating a bulklike interior for these active systems.

[Phys. Rev. E 97, 012702] Published Wed Jan 10, 2018

]]>We investigate dynamic magneto-optic effects in a ferromagnetic nematic liquid crystal experimentally and theoretically. Experimentally we measure the magnetization and the phase difference of the transmitted light when an external magnetic field is applied. As a model we study the coupled dynamics ...

[Phys. Rev. E 97, 012701] Published Fri Jan 05, 2018

]]>We present a comprehensive set of measurements of optical, dielectric, diamagnetic, elastic, and viscous properties in the nematic (N) phase formed by a liquid crystalline dimer. The studied dimer, 1,7-bis-4-(4′-cyanobiphenyl) heptane (CB7CB), is composed of two rigid rodlike cyanobiphenyl segments ...

[Phys. Rev. E 96, 062704] Published Tue Dec 26, 2017

]]>The present study is devoted to the investigation of the nonlinear optical properties of a smectic liquid crystal doped with gold nanorods. Using the $Z$-scan technique, we investigate the changes in the optical birefringence of a homeotropic sample upon laser exposure, considering the configurations ...

[Phys. Rev. E 96, 062703] Published Mon Dec 18, 2017

]]>The orientational order of the molecules in the bent mesogen CB6OCB has been studied throughout the range of temperature stability of both the ${N}_{\mathrm{U}}$ and ${N}_{\mathrm{TB}}$ liquid-crystal phases by ${}^{13}\mathrm{C}$ NMR spectroscopy. These spectra provide local order parameters for the *para* axes of both of the nonequivalent cyanobi...

[Phys. Rev. E 96, 062702] Published Fri Dec 15, 2017

]]>We analyzed the optical band gaps for axially propagating electromagnetic waves throughout a metallic doped cholesteric elastomer. The composed medium is made of metallic nanospheres (silver) randomly dispersed in a cholesteric elastomer liquid crystal whose dielectric properties can be represented ...

[Phys. Rev. E 96, 062701] Published Mon Dec 11, 2017

]]>The thermally excited vortical flow in a microsized liquid crystal (LC) volume with a free LC-air interface has been investigated theoretically based on the nonlinear extension of the Ericksen-Leslie theory, with accounting the entropy balance equation. Analysis of the numerical results show that du...

[Phys. Rev. E 96, 052705] Published Thu Nov 30, 2017

]]>We perform a series of Monte Carlo simulations on an interface between a liquid crystal (LC) material in isotropic phase in its bulk and a surfactant membrane. These two objects are simulated using coarse-grained molecular models. We estimate physical properties of the membrane such as the interfaci...

[Phys. Rev. E 96, 052704] Published Tue Nov 28, 2017

]]>A detailed investigation of the thermal and dielectric properties of a series of binary mixtures exhibiting the nematic ($N$) and twist-bend nematic (${N}_{\mathrm{TB}}$) liquid crystal phases is presented. The mixtures consist of an achiral, dimeric liquid crystal CB7CB, which forms the nematic and twist-bend nemati...

[Phys. Rev. E 96, 052703] Published Tue Nov 14, 2017

]]>A polymer-stabilized liquid crystal based on ${4}^{\prime}$-(octyloxy)biphenyl-4-carboxylate 2-fluoro-4-((octyl-2-yloxy)carbonyl)phenyl (D16) and 1,6 hexanediol diacrylate as a monomer was prepared by *in situ* photopolymerization. The selected antiferroelectric liquid crystal contains a fast-switching smectic ${C}_{\alpha}^{...}$

[Phys. Rev. E 96, 052702] Published Wed Nov 08, 2017

]]>Polymer-dispersed liquid crystal composites have been a focus of study for a long time for their unique electro-optical properties and manufacturing by “bottom-up” techniques at large scales. In this paper, nematic liquid crystal oblate droplets with conical boundary conditions (CBCs) under the acti...

[Phys. Rev. E 96, 052701] Published Mon Nov 06, 2017

]]>Visual evaluation of the surface anchoring energies in a nematic liquid crystal (LC) cell is characterized by the direction of the convection roll pattern that appears in the low-frequency conduction regime. The convection roll pattern in a twisted nematic LC (TNLC) cell is oriented perpendicular to...

[Phys. Rev. E 96, 040701(R)] Published Mon Oct 30, 2017

]]>We investigated the optical transmission properties of one-dimensional photonic crystal (1D-PC) microcavity structures containing the liquid-crystalline (LC) perylene tetracarboxylic bisimide (PTCBI) derivative. We fabricated the microcavity structures for this study by two different methods and obs...

[Phys. Rev. E 96, 042704] Published Thu Oct 19, 2017

]]>We investigate the isotropic, uniaxial nematic and biaxial nematic phases, and the transitions between them, for a model lyotropic mixture of flexible molecules consisting of two rigid rods connected by a spacer with variable bending stiffness. We apply density-functional theory within the Onsager a...

[Phys. Rev. E 96, 042703] Published Wed Oct 18, 2017

]]>We present numerical solutions to the Landau-de Gennes free-energy model under the one-constant approximation for systems of single and double spherical colloidal particles immersed in an otherwise uniformly aligned nematic liquid crystal. A perfect homeotropic surface anchoring of liquid-crystal mo...

[Phys. Rev. E 96, 042702] Published Fri Oct 06, 2017

]]>Calamitic liquid crystals based on 5-phenyl-pyrimidine derivatives have been designed, synthesized, and characterized. The 5-phenyl pyrimidine core was functionalized with a chiral (*R*,*R*)-2,3-epoxyhexoxy chain on one side and either siloxane or perfluoro terminated chains on the opposite side. The on...

[Phys. Rev. E 96, 042701] Published Tue Oct 03, 2017

]]>Time correlation functions in the Lebwohl-Lasher model of nematic liquid crystals are studied using theory and molecular dynamics simulations. In particular, the autocorrelation functions of angular momentum and nematic director fluctuations are calculated in the long-wavelength limit. The constitut...

[Phys. Rev. E 96, 032705] Published Thu Sep 28, 2017

]]>The performance of light-controlled liquid crystal anchoring surfaces depends on the nature of the photosensitive moieties and on the concentration of spacer units. Here, we study the kinetics of photosensitive liquid crystal cells that incorporate an azobenzene-based self-assembled monolayer. We ch...

[Phys. Rev. E 96, 032704] Published Mon Sep 25, 2017

]]>In this paper, we demonstrate the presence of a photonic band gap for a diamond lattice structure made of particles with normal anchoring inside a cholesteric liquid crystal. As is typical for liquid crystals (LCs), there is considerable contrast between the dielectric constant parallel ${\epsilon}_{\parallel}$ and perpe...

[Phys. Rev. E 96, 032702] Published Fri Sep 22, 2017

]]>General quadratic Hamiltonian models, describing the interaction between liquid-crystal molecules (typically with ${D}_{2h}$ symmetry), take into account couplings between their uniaxial and biaxial tensors. While the attractive contributions arising from interactions between similar tensors of the partici...

[Phys. Rev. E 96, 032703] Published Fri Sep 22, 2017

]]>Chiral smectic-$A$ liquid crystal elastomers are rubbery materials composed of a lamellar arrangement of liquid crystalline mesogens. It has been shown experimentally that these materials shear when subjected to an electric field due to the electrically induced tilt of the director. Experiments have a...

[Phys. Rev. E 96, 032701] Published Mon Sep 18, 2017

]]>The polarization exchange effect in a twisted-nematic Fabry-Pérot resonator is experimentally confirmed in the regimes of both uniform and electric-field-deformed twisted structures. The polarization of output light in the transmission peaks is shown to be linear rather than elliptical. The polariza...

[Phys. Rev. E 96, 022711] Published Tue Aug 29, 2017

]]>Nematic ($N$) liquid crystals made of bent-core molecules exhibit unusual physical properties such as an intermediate phase between the $N$ and isotropic ($I$) phases, a very weak $NI$ transition as inferred from magnetic birefringence measurements in a low field, which is apparently incompatible with a lar...

[Phys. Rev. E 96, 022710] Published Thu Aug 17, 2017

]]>We propose an approach to a multiscale problem in the theory of thermotropic uniaxial nematics based on the method of statistical field theory. This approach enables us to relate the coefficients $A$, $B$, $C$, ${L}_{1}$, and ${L}_{2}$ of the Landau-de Gennes free energy for the isotropic-nematic phase transition to th...

[Phys. Rev. E 96, 022709] Published Tue Aug 15, 2017

]]>We present a Monte Carlo simulation study of suspensions of hard ellipsoids of revolution. Based on the spatial fluctuations of the orientational order, we have computed the Frank elastic constants for prolate and oblate ellipsoids and compared them to the affine transformation model. The affine tra...

[Phys. Rev. E 96, 022708] Published Mon Aug 14, 2017

]]>Interfacial defect shedding is the most recent known mechanism for defect formation in a thermally driven isotropic-to-nematic phase transition. It manifests in nematic-isotropic interfaces going through an anchoring switch. Numerical computations in planar geometry established that a growing nemati...

[Phys. Rev. E 96, 022707] Published Fri Aug 11, 2017

]]>Results of broadband dielectric spectroscopy (BDS) studies of pure liquid crystalline (4-pentyloxy-4-biphenylcarbonitryle) 5OCB and its nanocolloids with ${\mathrm{BaTiO}}_{3}$ nanoparticles (NPs) under varying pressure and temperature are presented. The notable impact of NPs on phase transitions and dynamics was f...

[Phys. Rev. E 96, 022705] Published Wed Aug 09, 2017

]]>This paper studies the change in shape of nematic droplets under the influence of an electric field, using experiments and numerical simulations. A reversible elongation is possible due to the low elasticity of the liquid crystal and its strong anchoring. The authors are able to observe changes in the aspect ratio up to ten, which may influence the optical properties of the material.

[Phys. Rev. E 96, 022706] Published Wed Aug 09, 2017

]]>The celebrated work of Onsager on hard particle systems, based on the truncated second order virial expansion, is valid at relatively low volume fractions for large aspect ratio particles. While it predicts the isotropic-nematic phase transition, it does not provide a realistic equation of state in ...

[Phys. Rev. E 96, 022704] Published Mon Aug 07, 2017

]]>We experimentally study the effect of temperature and electric field on the quality $\left(Q\right)$ factor and free spectral range (FSR) of whispering-gallery-mode optical resonance of dye-doped nematic liquid crystal microdroplets. Both the $Q$ factor and the FSR are highly sensitive to the temperature and elect...

[Phys. Rev. E 96, 022702] Published Fri Aug 04, 2017

]]>We theoretically study the influence of the liquid crystal (LC) orientational state on the absorption, reflection, and transmission spectra of a graphene microribbon grating placed between a nematic LC and an isotropic dielectric substrate. We calculate the absorption, reflection, and transmission c...

[Phys. Rev. E 96, 022703] Published Fri Aug 04, 2017

]]>Light-induced modulations of the refractive index and pattern formation are desirable to generate complex photonic structures via exposure to light. Here we show that local modulations of the effective refractive index and reconfigurable defects can be *locally* induced in a hybridized thin birefringe...

[Phys. Rev. E 96, 022701] Published Wed Aug 02, 2017

]]>We explore reshaping of nematoelastic films upon imbibing an isotropic solvent under conditions when isotropic and nematic phases coexist. The structure of the interphase boundary is computed taking into account the optimal nematic orientation governed by interaction of gradients of the nematic orde...

[Phys. Rev. E 96, 012709] Published Mon Jul 31, 2017

]]>Cholesteric liquid crystals experience geometric frustration when they are confined between surfaces with anchoring conditions that are incompatible with the cholesteric twist. Because of this frustration, they develop complex topological defect structures, which may be helicoids or skyrmions. We de...

[Phys. Rev. E 96, 012708] Published Fri Jul 28, 2017

]]>A small quantity of monolayer graphene flakes is doped in a nematic liquid crystal (LC), and the effective polar anchoring strength coefficient between the LC and the alignment substrate is found to increase by an order of magnitude. The hexagonal pattern of graphene can interact with the LC's benze...

[Phys. Rev. E 96, 012707] Published Thu Jul 27, 2017

]]>A long time ago, Brochard and de Gennes predicted the possibility of significantly decreasing the critical magnetic field of the Fredericksz transition (the magnetic Fredericksz threshold) in a mixture of nematic liquid crystals and ferromagnetic particles, the so-called ferronematics. This phenomen...

[Phys. Rev. E 96, 012706] Published Mon Jul 24, 2017

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