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We investigate the two-dimensional behavior of colloidal patchy ellipsoids specifically designed to follow a two-step assembly process from the monomer state to mesoscopic liquid-crystal phases via the formation of the so-called bent-core units at the intermediate stage. Our model comprises a binary mixture of ellipses interacting via the Gay–Berne potential and decorated by surface patches, with the binary components being mirror-image variants of each other—referred to as left-handed and right-handed ellipses according to the position of their patches. The surface patches are designed so as in the first stage of the assembly the monomers form bent-cores units, i.e., V-shaped dimers with a specific bent angle. The Gay–Berne interactions, which act between the ellipses, drive the dimers to subsequently form the characteristic phase observed in bent-core liquid crystals. We numerically investigate—by means of both Molecular Dynamics and Monte Carlo simulations—the described two-step process: we first optimize a target bent-core unit and then fully characterize its state diagram in temperature and density, defining the regions where the different liquid crystalline phases dominate. [ABSTRACT FROM AUTHOR]

Guiding and dynamically modulating topological defects are critical challenges in defect engineering of liquid crystals. Here, we employ molecular dynamics simulations to investigate the transition dynamics and relative kinetic stability of defect patterns in two-dimensional nematic Gay–Berne liquid crystals confined within rectangular geometries. We observe the formation of various defect patterns including long-axis, diagonal, X-shaped, composite, and bend configurations under different confinement conditions. The competition between boundary effects and the uniformity of nematic orientation induces the continuous realignment of liquid crystal molecules, facilitating the spatially continuous transformation of defect patterns over time. This transition involves changes in both defect types and their locations, typically initiating from defect regions. Furthermore, we demonstrate that the relative stability of these defect patterns can be effectively controlled by adjusting confinement parameters and external field conditions. Our findings provide fundamental insights into the transition kinetics of defect patterns in confined nematic liquid crystals, thereby enhancing our ability to manipulate topological defects for advanced applications. [ABSTRACT FROM AUTHOR]

Physics-based, atom-centered machine learning (ML) representations have been instrumental to the effective integration of ML within the atomistic simulation community. Many of these representations build off the idea of atoms as having spherical, or isotropic, interactions. In many communities, there is often a need to represent groups of atoms, either to increase the computational efficiency of simulation via coarse-graining or to understand molecular influences on system behavior. In such cases, atom-centered representations will have limited utility, as groups of atoms may not be well-approximated as spheres. In this work, we extend the popular Smooth Overlap of Atomic Positions (SOAP) ML representation for systems consisting of non-spherical anisotropic particles or clusters of atoms. We show the power of this anisotropic extension of SOAP, which we deem AniSOAP, in accurately characterizing liquid crystal systems and predicting the energetics of Gay–Berne ellipsoids and coarse-grained benzene crystals. With our study of these prototypical anisotropic systems, we derive fundamental insights on how molecular shape influences mesoscale behavior and explain how to reincorporate important atom–atom interactions typically not captured by coarse-grained models. Moving forward, we propose AniSOAP as a flexible, unified framework for coarse-graining in complex, multiscale simulation. [ABSTRACT FROM AUTHOR]

Given the significant progress in the field of meta-lenses over the past decade, tunable meta-lenses have garnered considerable attention for their flexible functionality. Various mechanisms have been developed to realize high-performance tunable meta-lenses, including electricity, strain, thermal effects, and materials, such as phase-change materials and liquid crystals. However, currently, most tunable meta-lenses are limited to discrete focal lengths, typically only involving two spots, and the potential of phase-change materials, such as Ge2Sb2Te5, Sb2S3, etc., has not yet been fully exploited. Here, we propose a design approach to achieve tunable meta-lenses with continuous focal length manipulation working at 1550 nm based on phase-change materials (Sb2S3). The focal length can be gradually tuned from 35 to 55 μm during the conversion process between crystalline and amorphous states. The meta-atoms are rectangular shapes of different sizes and orientations to provide certain phase compensations from propagation and Pancharatnam–Berry phases, respectively. The tunable Airy beam, Bessel beam, and deflection of the meta-lens focal spot are also demonstrated to show the universality of the proposed design. This endeavor will lay the groundwork for the design of tunable meta-devices, thereby streamlining their integration into infrared systems. [ABSTRACT FROM AUTHOR]

Patchy particles are an intriguing subject of study and indeed a model system in the field of soft matter physics. In recent years, patchy particle models have been applied to describe a wide variety of systems, including colloidal crystals, macromolecular interactions, liquid crystals, and nanoparticle assemblies. Given the importance of the topic, rationalizing and capturing the basic features of these models is crucial to their correct application in specific systems. In this study, we extend the ion-activated attractive patchy particles model previously employed to elucidate the phase behavior of protein solutions in the presence of trivalent salts. Our extension incorporates the effect of repulsion between unoccupied and occupied binding sites, depicted as patches. Furthermore, we examine the influence of model parameters on the liquid–vapor coexistence region within the phase diagram, employing numerical methods. A deeper understanding of this model will facilitate a better comprehension of the effects observed in experiments. [ABSTRACT FROM AUTHOR]

We investigated the spectrum of density fluctuations of a liquid crystal, CB7CB, in two different orientations by using high-resolution inelastic x-ray scattering. Our analysis, based on Bayesian principles, revealed that high-frequency collective excitations propagate through this mesoscale-ordered sample in a peculiar manner that lies somewhere between those observed in liquids and crystalline systems. Interestingly, when we probed longer length scales, a more pronounced solid-like response emerged. This was mainly characterized by anomalously sharp inelastic excitations and the onset of shear mode propagation. Comparison with previous x-ray diffraction results suggests a correlation between the observed behavior and the mesogen arrangement. [ABSTRACT FROM AUTHOR]

High tilt angle (45 °) ferroelectric liquid crystal (F L C) in surface stabilized geometry, having no chiral smectic A (S m A ∗) phase, has been studied for the reorientation of the smectic layers near the transition temperature (T c). The electro-optical studies have shown the stripe domain formation in which the liquid crystal molecules are aligned along the rubbing direction, but the smectic layers are tilted away from the rubbing direction at room temperature. In such high tilt angle F L C s , the molecular alignment and smectic layer formation start from bottom and top rubbed grooves at T c. The domain formation of the FLC takes place in the middle of the top and bottom surfaces due to the frustration of the dipolar interaction. The smectic layer switching is observed by optical microscopy and confirmed by the dielectric spectroscopy method near T c of S m C ∗ and chiral nematic phases. Domain switching has shown a larger switching angle than the molecular tilt angle within the smectic layer. These studies are expected to be significant for understanding the smectic layer structure and the domain switching process, which may pave the way for large optical switching devices. [ABSTRACT FROM AUTHOR]

Liquid crystals consisting of biaxial particles can exhibit a much richer phase behavior than their uniaxial counterparts. Usually, one has to rely on simulation results to understand the phase diagram of these systems since very few analytical results exist. In this work, we apply fundamental measure theory, which allows us to derive free energy functionals for hard particles from first principles and with high accuracy, to systems of hard cylinders, cones, and spherotriangles. We provide a general recipe for incorporating biaxial liquid crystal order parameters into fundamental measure theory and use this framework to obtain the phase boundaries for the emergence of orientational order in the considered systems. Our results provide insights into the phase behavior of biaxial nematic liquid crystals and, in particular, into methods for their analytical investigation. [ABSTRACT FROM AUTHOR]

We study an air–crown glass planar interface that includes a thin layer of a cholesteric liquid crystal doped with silver spheres of nanometer size. We propose a new theoretical model for the propagation of electromagnetic waves through the liquid crystal part and use the Marcuvitz–Schwinger form of the Maxwell equations to compute guided surface wave profiles. The results suggest the presence of anisotropic surface modes with negligible attenuation. The dependence of the surface wave parameters on the liquid crystal layer parameters can be used in liquid crystal-based sensors. [ABSTRACT FROM AUTHOR]

This study is concerned with a theory of two-step nucleation and growth of crystals in a metastable liquid. This mechanism is that crystalline nuclei formation occurs in dense liquid clusters suspended in the solution. These clusters contain higher solution concentration and viscosity, leading to a lower surface free energy barrier and faster phase transition route. The theory is based on growth laws of crystals during the two-step bulk phase transformation. At the initial stage, the crystals evolve in a diffusion-limited environment with almost unchanged supersaturation. At the second stage, they become larger, move beyond these clusters, and evolve in accordance with a hyperbolic tangent law. A generalized particle growth law joining the first and second stages is obtained by stitching the diffusion limited and hyperbolic tangent laws. On this basis, an integrodifferential model of the evolution of a polydisperse ensemble of crystals was formulated and solved. The crystal-size distribution function increases and the solution supersaturation remains practically unchanged until the particle size corresponds to a transition in the particle growth rate from a diffusion-limited branch to a hyperbolic tangent branch. This is followed by an increase in the crystal growth rate, a decrease in the distribution function and solution supersaturation. Then the distribution function increases up to the maximum size of crystals grown in the solution. A sufficiently long time interval of almost constant supersaturation and the N-shaped behavior of the distribution function are the consequences of a two-step nucleation and growth mechanisms. [ABSTRACT FROM AUTHOR]

Confined liquid crystals (LCs) exhibit complex and intriguing structures, which are fascinating fundamental problems in soft matter. The helical structure of cylindrical cavities is of great importance in LC studies, particularly for their application in optical devices. In this study, we employ molecular dynamics simulations to explore the behavior of achiral smectic-B LCs confined in narrow cylindrical cavities, where geometric frustration plays an important role. By increasing the cylinder size, LCs exhibit a transition from multi-helical to layered structures. Notably, we observe two stable structures, namely the helical structure and the layered structure, at moderate cylinder size. We also investigate the effects of the arrangement of cylindrical wall particles (hexagonal or square array) and anchoring strength on the LC structure. Our findings reveal that both the hexagonal array and strong anchoring strength promote the formation of helical structures. Our study provides novel insights into the confinement physics of LCs and highlights the potential for achieving helical structures in achiral LCs, which will expand the future applications of LCs. [ABSTRACT FROM AUTHOR]

A chiral supramolecular liquid crystal based on a pillararene mesogen was constructed. The regulation of liquid crystal behavior was achieved through the host–guest interactions between the pillararene-based mesogen and a tetraphenylethylene-containing guest. In addition, this supramolecular liquid crystal system, showing pH-responsive fluorescence emission character, was applied as an information encryption material capable of storing multiple levels of distinct information, thereby enriching the application of liquid crystal materials in the field of information security. [ABSTRACT FROM AUTHOR]

Replicating the microstructural basis and the near 100% excitation energy transfer efficiency in naturally occurring light‐harvesting complexes (LHCs) remains challenging in synthetic energy‐harvesting devices. Biological photosynthesis regulates active ensembles of light‐absorbing and funneling chlorophylls in proteins in response to fluctuating sunlight. Here, use of long‐range liquid crystal (LC) ordering to tailor chain orientation and packing structure in liquid crystalline conjugated polymer (LCCP) layers for bio‐mimicry of certain structural basis and light‐harvesting properties of LHCs is reported. It is found that long‐range orientational ordering in an LC phase of poly(9,9‐dioctylfluorene‐co‐benzothiadiazole) (F8BT) copolymer stabilizes a small fraction of randomly‐oriented F8BT nanocrystals dispersed in an amorphous matrix of F8BT chains, resembling a self‐doped host–guest system whereby excitation energy funneling and photoluminescence quantum efficiencies are enhanced significantly by triggering 3D donor‐to‐acceptor Förster resonance energy transfer (FRET) and dominant intrachain emission in the nano‐crystal acceptor. Further, photoalignment of nematic F8BT layers is combined with LC orientational ordering to fabricate large‐area‐extended monodomains exhibiting >60% crystallinity and ≈20 nm‐long interchain packing order. Remarkably, these monodomains demonstrate strong linearly polarized emission, whilst also promoting a new band‐edge absorption species and an extra emissive interchain excited state as compared to the non‐aligned films. [ABSTRACT FROM AUTHOR]

Structural colors based on metasurfaces outperform traditional pigments and dyes in terms of nonfading, high spatial resolution, and high stability, usually incorporating active materials for tunability. Liquid crystals (LCs) are suitable for tunable structural color design due to their large birefringence and fast modulation by external stimuli. However, most LC‐integrated structural colors focus on tailoring the polarization angle of incident light to generate two colors and their mixing. Herein, a scheme of full‐color generation based on a plasmonic metasurface integrated with LCs utilizing the combination of the polarization angle rotation effect of the twisted‐nematic LCs and the refractive index modulation through the realignment of the LCs near the metasurface is demonstrated. Based on the proposed structural color method, full‐color generation of a record color gamut of 60.7% standard Red Green Blue region, equivalent to 43% National Television Standards Committee area, in the LC‐integrated metasurface, has been numerically realized by tuning the bias voltage of the LCs in reflection. The achieved color gamut is nearly 4 times wider than the previously reported result. The proposed active full‐color generation metasurface shows great potential in applications for low‐power reflective color display, anticounterfeiting, and optical encoding. [ABSTRACT FROM AUTHOR]

A new integrated electrode-separator-electrolyte hydrogel is designed and prepared, which is composed of organic liquid crystal, polyvinyl alcohol (PVA), polyaniline (PANI), and reduced graphene oxide (rGO). The organic liquid crystal is introduced into PVA hydrogel, effectively improving compatibility between active materials and hydrogel matrix. The PANI active material is in situ polymerized in hydrogel to prepare PANI-double-network hydrogel. It simultaneously acts as electrode, separator, and electrolyte for assembling flexible solid-state supercapacitor. It obtains an area-specific capacitance of 160.2 mF/cm2 and a power density of 101.5 μW/cm2 with an energy density of 21.0 μWh/cm2. This work provides a new method to reduce interfacial resistance of electrode, separator, and electrolyte of flexible solid-state supercapacitor, further improving its electrochemical performance. [ABSTRACT FROM AUTHOR]

This article investigates the interaction of nematic liquid crystals modeled by a simplified Ericksen-Leslie model with a rigid body. It is shown that this problem is locally strongly well-posed, and that it also admits a unique, global strong solution for initial data close to constant equilibria. The proof of the global strong solution relies on a new splitting method for the director in a mean value zero and average part. [ABSTRACT FROM AUTHOR]

A review of the recent developments in the field of lasing with liquid crystals (LCs) is presented. After an introduction into the principle of lasing the different relevant liquid crystal phases to the field are introduced, namely, the nematic and chiral nematic phase, Blue Phases, twist grain boundary and ferroelectric liquid crystals. The classic examples of liquid crystal lasing are shortly discussed, together with a variety of possibilities for tuning the lasing wavelength, before the modern trends in LC lasing are discussed in detail. These are particularly random lasers, where the effects of nanoparticles, quantum dots and solitons are highlighted, as well as localized surface plasmon resonance. Other modern laser systems that have attracted recent interest, white lasers, whispering gallery mode lasers and those with biological materials, for example, cellulose nanocrystals, are also introduced and the latest developments outlined. [ABSTRACT FROM AUTHOR]

Conventional absorbing, reflective and scattering polarizers are facing various issues, such as severe optical loss, necessary oblique incidence, humidity sensitivity or aging‐caused failure. Subnanowires (SNWs) with polymer‐analogue properties, intrinsic order, and multi‐level interactions attract widespread attention as superior candidates for building blocks of polarizers. Herein, freestanding and flexible liquid crystal (LC)‐SNW films are prepared through a facile directional coating method, not only exhibiting good stability for water and repeated temperature fluctuations, but also showing good polarization performance for visible and near‐infrared (NIR) light, with the polarization degree (P) values of 93%, 84%, and 63% at the wavelengths of 580, 780 and 960 nm. And the average haze achieves 85%. The LC‐SNW films have great potential in applications for polarizers, holographic projection imaging and flexible optical devices. [ABSTRACT FROM AUTHOR]

Dynamic covalent bonds endow liquid crystal elastomers (LCEs) with network rearrangeability, facilitating the fixation of mesogen alignment induced by external forces and enabling reversible actuation. In comparison, the bond exchange of supramolecular interactions is typically too significant to stably maintain the programmed alignment, particularly under intensified external stimuli. Nevertheless, remaking and recycling of supramolecular interaction‐based polymer networks are more accessible than those based on dynamic covalent bonds, as the latter are difficult to completely dissociate. Thus, preparing an LCE that possesses both supramolecular‐like exchangeability and covalent bond‐level stability remains a significant challenge. In this work, we addressed this issue by employing metal‐ligand bonds as the crosslinking points of LCE networks. As such, mesogen alignment can be repeatedly encoded through metal‐ligand bond exchange and stably maintained after programming, since the bond exchange rate is sufficiently slow when the programming and actuation temperatures are below the bond dissociation temperature. More importantly, the metal‐ligand bonds can be completely dissociated at high temperatures, allowing the LCE network to be dissolved in a solvent and reshaped into desired geometries via solution casting. Building on these properties, our LCEs can be fabricated into versatile actuators, such as reversible folding origami, artificial muscles, and soft robotics. [ABSTRACT FROM AUTHOR]

Dynamic covalent bonds endow liquid crystal elastomers (LCEs) with network rearrangeability, facilitating the fixation of mesogen alignment induced by external forces and enabling reversible actuation. In comparison, the bond exchange of supramolecular interactions is typically too significant to stably maintain the programmed alignment, particularly under intensified external stimuli. Nevertheless, remaking and recycling of supramolecular interaction‐based polymer networks are more accessible than those based on dynamic covalent bonds, as the latter are difficult to completely dissociate. Thus, preparing an LCE that possesses both supramolecular‐like exchangeability and covalent bond‐level stability remains a significant challenge. In this work, we addressed this issue by employing metal‐ligand bonds as the crosslinking points of LCE networks. As such, mesogen alignment can be repeatedly encoded through metal‐ligand bond exchange and stably maintained after programming, since the bond exchange rate is sufficiently slow when the programming and actuation temperatures are below the bond dissociation temperature. More importantly, the metal‐ligand bonds can be completely dissociated at high temperatures, allowing the LCE network to be dissolved in a solvent and reshaped into desired geometries via solution casting. Building on these properties, our LCEs can be fabricated into versatile actuators, such as reversible folding origami, artificial muscles, and soft robotics. [ABSTRACT FROM AUTHOR]

The fabrication of pressure-sensitive adhesives (PSA) using liquid crystal elastomers (LCE) that are tolerant to substrate roughness is explored in this work. Traditional soft adhesives are designed by maintaining a balance between their cohesive strength and compliance. However, rough surfaces can significantly affect the adhesion strength of PSAs. Lowering the stiffness of the adhesive by reducing the cross-linking density or using additives can improve contact on rough surfaces. But this also decreases the cohesive strength and affects the overall performance of the adhesive. Additive-free LCE-based adhesives are shown to overcome these challenges due to their unique properties. Soft elasticity of LCE and low cross-link density contribute to their high compliance, while moderate cross-linking provides finite strength. The effect of contact time and substrate roughness on the adhesive performance is evaluated using probe-tack, indentation, lap shear, and static loading experiments. The unique combination of properties offered by LCE can lead to the development of roughness-tolerant adhesives, thereby broadening the application scope of PSAs. [ABSTRACT FROM AUTHOR]

Dynamic covalent liquid crystal networks (DCv‐LCNs) with straightforward (re)programmability, reprocessability, and recyclability facilitates the manufacture of sophisticated LCN actuators and intelligent robots. However, the DCv‐LCNs are still limited to heat‐assisted programming and polymer‐to‐polymer reprocessing/recycling, which inevitably lead to deterioration of the LCN structures and the actuation performances after repeated programming/processing treatments, owing to the thermal degradation of the polymer network and/or external agent interference. Here, a totally renewable azobenzene‐based DCv‐LCN with room‐temperature programmability and polymer‐to‐monomers chemical recyclability is reported, which was synthesized by crosslinking the azobenzene‐containing dibenzaldehyde monomer and the triamine monomer via the dynamic and dissociable imine bonds. Thanks to the water‐activated dynamics of the imine bonds, the resultant DCv‐LCN can be simply programmed, upon water‐soaking at room temperature, to yield a UV/Vis light‐driven actuator. Importantly, the reported DCv‐LCN undergoes depolymerization in an acid‐solvent medium at room temperature because of the acid‐catalyzed hydrolysis of the imine bonds, giving rise to easy separation and recovery of both monomers in high purity, even with tolerance to additives. The recovered pure monomers can be used to regenerate totally new DCv‐LCNs and actuators, and their functionalities can be reconfigured by removing old and introducing new additives, by implementing the closed‐loop polymer‐monomers‐polymer recycling. [ABSTRACT FROM AUTHOR]

Dynamic covalent liquid crystal networks (DCv‐LCNs) with straightforward (re)programmability, reprocessability, and recyclability facilitates the manufacture of sophisticated LCN actuators and intelligent robots. However, the DCv‐LCNs are still limited to heat‐assisted programming and polymer‐to‐polymer reprocessing/recycling, which inevitably lead to deterioration of the LCN structures and the actuation performances after repeated programming/processing treatments, owing to the thermal degradation of the polymer network and/or external agent interference. Here, a totally renewable azobenzene‐based DCv‐LCN with room‐temperature programmability and polymer‐to‐monomers chemical recyclability is reported, which was synthesized by crosslinking the azobenzene‐containing dibenzaldehyde monomer and the triamine monomer via the dynamic and dissociable imine bonds. Thanks to the water‐activated dynamics of the imine bonds, the resultant DCv‐LCN can be simply programmed, upon water‐soaking at room temperature, to yield a UV/Vis light‐driven actuator. Importantly, the reported DCv‐LCN undergoes depolymerization in an acid‐solvent medium at room temperature because of the acid‐catalyzed hydrolysis of the imine bonds, giving rise to easy separation and recovery of both monomers in high purity, even with tolerance to additives. The recovered pure monomers can be used to regenerate totally new DCv‐LCNs and actuators, and their functionalities can be reconfigured by removing old and introducing new additives, by implementing the closed‐loop polymer‐monomers‐polymer recycling. [ABSTRACT FROM AUTHOR]

Novel liquid crystal elastomers (LCEs) with solely Diels–Alder dynamic covalent bonds (DADCBs) as crosslinks and body temperature sensitivity have been developed. The appealing attributes of the material, such as recyclability, reprogrammability and reconfigurability, have led to soft actuators capable of reversible deformation stimulated by shifting between ambient and body temperature, highlighting the potential for innovative applications in the biomedical field. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) can self‐assemble to form cholesteric liquid crystal, which make it one of the most promising optical materials at present. CNCs can be produced by sulfuric acid hydrolysis. It is found that hydrolysis conditions influence the existing form of reaction components and their reaction activities, which leads to different reaction routes and mechanisms under varied reaction conditions, with CNCs of varied quality produced. High‐quality CNC with more uniform particle size could be prepared at a critical acid concentration of 64 wt%, which was used to study the formation process of CNC liquid crystal and the structure regulation of cholesteric liquid crystal. By adjusting the drying temperature and adding a small molecule of water‐soluble chitosan (WSC) can well regulate cholesteric liquid crystal and change the pitch of a film, and the reflection wavelength can be redshifted, thus enriching texture patterns and creating distinctive color. Suitable addition of WSC can enhance the multi‐domain effect during liquid crystal formation process and finally creates more colorful film with fine texture. The rich and tunable liquid crystal characteristics endowed by WSC addition is irreplicable and artistic, which helps to realize the great potential application of the composite film in advanced anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Nanostructured polymer-dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce birefringence by applying an electric field (E-field) based on the reorientation of the LC molecules. If nano-PDLCs are utilized as light-scattering-less birefringence memory materials, it is necessary to suppress the relaxation of the LC molecule orientation after the removal of the E-field. We focused on the ferroelectric smectic A (SmA) phase to suppress the relaxation of LC molecules, owing to its layered structure and high viscosity. Although nano-PDLCs require a strong E-field to reorient their LC molecules because of the anchoring effect at the LC/polymer interface, the required field strength can be reduced using a ferroelectric smectic A (SmAF) LC with a large dielectric constant. In this study, we fabricated a nano-PDLC by shining an ultraviolet light on a mixture comprised an SmAF LC, photocurable monomers, and a photo-initiator. The electro-birefringence effect was evaluated using polarizing optical microscopy. After the removal of the E-field, an enhanced memory effect was observed in the sample using SmAF LC compared with nematic LC-based nano-PDLCs. [ABSTRACT FROM AUTHOR]

Using liquid crystals in near-infrared applications suffers from effects related to processes like parasitic absorption and high sensitivity to UV-light exposure. One way of managing these disadvantages is to use deuterated systems. The combined 1H and 2H nuclear magnetic resonance relaxometry method (FFC NMR), dielectric spectroscopy (DS), optical microscopy (POM), and differential scanning calorimetry (DSC) approach was applied to investigate the influence of selective deuteration on the molecular dynamics, thermal properties, self-organization, and electric-field responsiveness to a 4′-pentyl-4-biphenylcarbonitrile (5CB) liquid crystal. The NMR relaxation dispersion (NMRD) profiles were analyzed using theoretical models for the description of dynamics processes in different mesophases. Obtained optical textures of selectively deuterated 5CB showed the occurrence of the domain structure close to the I/N phase transition. The dielectric measurements showed a substantial difference in switching fields between fully protonated/deuterated 5CB and selectively deuterated molecules. The DSC thermograms showed a more complex phase transition sequence for partially deuterated 5CB with respect to fully protonated/deuterated molecules. [ABSTRACT FROM AUTHOR]

Nonlinear electrophoresis in complex fluids like nematic liquid crystals provides new pathways toward achieving precisely controlled motion and assembly of microscopic objects. The nematic host introduces a paradigm shift in the mechanism of electrophoretic transport by generating unbalanced electro-osmotic flows around the colloidal particle due to symmetry breaking of the medium caused by the induced topological defects. Rationally designed particles, which induce various types of defects and asymmetries, provide new opportunities in this regard. In this Perspective article, we discuss how the asymmetry in the shape and interfacial properties help in piloting the particles using an AC electric field. Finally, we propose some feasible strategies to achieve navigational control using magnetic and photo-responsive particles, guided by orthogonal electric, magnetic fields, and light, respectively. [ABSTRACT FROM AUTHOR]

We give a homotopy classification of the global defects in ordered media and explain it via the example of biaxial nematic liquid crystals, that is, systems where the order parameter space is the quotient of the three-sphere S3 by the quaternion group Q. As our mathematical model, we consider continuous maps from complements of spatial graphs to the space S3/Q modulo a certain equivalence relation and find that the equivalence classes are enumerated by the six subgroups of Q. Through monodromy around meridional loops, the edges of our spatial graphs are marked by conjugacy classes of Q ; once we pass to planar diagrams, these labels can be refined to elements of Q associated with each arc. The same classification scheme applies not only in the case of Q but also to arbitrary groups. [ABSTRACT FROM AUTHOR]

Radiative cooling has been recently intensively explored for thermal management and enhancing energy efficiency. Yet, traditional materials with singular emissivity fall short in dynamic thermal management, highlighting the need for materials that can adjust their thermal radiation in real time. Active modulation methods, requiring external stimuli such as mechanical stretch, electric potential, or humidity change, offer adaptability but can increase energy use and complexity. Passive approaches, using materials' inherent thermal‐responsive properties, face manufacturing and scalability challenges. Here, a scalable yet effective passive approach is introduced for adaptive thermal modulation based on gold (Au) and liquid crystal elastomer (LCE) with a reversible response to environmental temperature changes. This modulator enables a "low thermal resistance" state through actuation‐induced microcracks that expose a high‐emissivity polymer substrate, and a "high thermal resistance" state by closing these microcracks and forming a high thermal resistance air gap between the modulator and the target object. The flexible design and fixed external dimensions of the Au‐LCE thermal modulator make it adaptable to various surface geometries. Furthermore, by adjusting the LCE's chemical composition, the modulator's transition temperature can be tailored, broadening its applications from enhancing building energy efficiency to improving clothing thermal comfort. [ABSTRACT FROM AUTHOR]

The document from Chemical Communications, published in 2024, provides a comprehensive list of articles covering various topics in chemistry. It includes research on electrochemical deconstructive functionalization, organoboron catalysis, recent progress in sensing technologies, and advancements in metal carbene-induced rearrangements. The journal aims to uncover new possibilities through original discoveries and fundamental questions in the field of chemistry. [Extracted from the article]

We designed V-shaped ionic liquid crystals with two sterically congested ionic parts at the vertex. Depending on the degree of steric hindrance, atropisomerisation occurred in solution. All compounds formed bicontinuous cubic phases with double-gyroid structures in the bulk state, partially owing to the co-existence of atropisomers with opposite chirality. [ABSTRACT FROM AUTHOR]

We study the optical and electrowetting (EW) property of polymer-dispersed liquid crystal (PDLC) dielectric. The dielectric films of nematic liquid crystal (LC) dispersed in polymethyl methacrylate matrix were characterized using polarized optical microscope and luminescence spectroscopy. The photoluminescence (PL) spectra show shift in peak emission wavelength due to the variation in refractive index between dispersed LC phase in the polymer matrix. The distribution of optically active LC phase plays a major role in the light scattering process. The LC concentration in polymer matrix varying from 10 to 70 wt % shows enhancement in PL intensity. Also, reduction in the PL peak broadening indicates improvement in optical properties. Finally, electrowetting using saline water on the PDLC dielectric was investigated for ac voltage as well as for dc voltages. The dielectric constant for PDLC obtained from EW response and impedance analyzer is in good agreement. The asymmetry in EW response indicates a trapping of charges in the PDLC dielectric, where magnitude of charge trapping increases with LC concentration. Our results provide insights into the intricate mechanisms influencing optical and EW properties, guiding the development of advanced materials for displays, lenses, and optoelectronics applications. [ABSTRACT FROM AUTHOR]

The multifunctional responsive interfaces of liquid crystal (LC) and water are employed in fundamental research (colloidal assembly) and promising applications (sensing, release, and material synthesis). The stagnant LC systems, however, limit their use in continuous, automated applications. A microfluidic platform is reported where stable LC flow is maintained between aqueous interfaces. The LC‐water soft interface is defined by the preferential wetting of the two phases at the chemically heterogeneous microchannel interfaces. It is shown that the LC‐water interfaces are stable up to significant pressure differences across the interfaces and maintain responsive characteristics. The stability is in a range to cover the perpendicular and flow‐aligned regimes at low and high flow velocities, respectively, in co‐current or counter‐current flow configurations. The LC configuration at the vicinity of the aqueous interfaces is influenced by the shear induced by the bulk LC flow and by the contacting aqueous phases allowing modulation of the LC strain at the responsive interfaces. The simplicity of the construction and operation of the soft‐interface LC flow platform shows promise and meets the fundamental requirements for their integration into next‐generation autonomous platforms. [ABSTRACT FROM AUTHOR]

Evaporation‐induced self‐assembly (EISA) is a versatile method for generating organized superstructures from colloidal particles, offering diverse design possibilities through the manipulation of colloid size, shape, substrate nature, and environmental conditions. While some work highlighted the potential of EISA to investigate phase transitions of inorganic liquid crystals, the influence of sample environment to determine their phase diagrams is often overlooked. In this work, the self‐assembly of lyotropic liquid crystals is compared by EISA on substrates, and by acoustic levitation (absence of substrate). The focus is on imogolite nanotubes, a model colloidal system of 1D charged objects, due to their tunable morphology and rich liquid‐crystalline phase behavior. It demonstrates the feasibility to obtain phase transitions in levitating droplets and on soft hydrophobic substrates, whereas self‐assembly is limited on rigid hydrophilic supports. Moreover, the aspect ratio of the nanotubes proves to be a pivotal factor, influencing both transitions and the resulting materials shape and surface. Besides material shaping, acoustic levitation emerges as a promising method for studying phase transitions by EISA, toward the rapid establishment of phase diagrams from diluted to highly concentrated states using a limited volume of sample. [ABSTRACT FROM AUTHOR]

The design and engineering of liquid crystal elastomers (LCE) composites for enhanced multifunctionality and responsiveness is highly desired. Here, a hollow LCE (h‐LCE) fiber fabricated via coaxial spinning, enabling the straightforward yet effective creation of functional LCE composites, is reported. Inspired by the fiber‐tubule architecture in skeletal muscles, the hollow fiber features an LCE outer shell for programmable actuation and an inner channel allowing for the integration of a variety of functional media. Thus, the h‐LCE fiber can serve as a versatile platform for multifunctionalities in LCE composites. With this unique design strategy, h‐LCE fibers are fabricated with lengths exceeding 3 meters in the lab with outer and inner diameters as small as 250 mm and 120 µm, respectively. The versatility of these h‐LCE fibers across various applications are further demonstrated, from fast‐response stiffness‐tunable actuators by integrating water flow as triggering media and shape memory polymer (SMP) for enhanced mechanical properties, to electrically driven actuating systems through the incorporation of liquid metal, and actuating light‐guides by combining SMP and PDMS optical fiber. The conception of h‐LCE fiber not only advances the design of multifunctional LCE composites but also paves the way for their application in soft robotics, artificial muscles, and beyond. [ABSTRACT FROM AUTHOR]

Structured light refers to the light field tailored by various degrees of freedom including intensity, phase, and polarization states in both spatial and temporal domains, which may greatly vitalize the technologies in both optics, such as the next‐generation optical communication as well as subwavelength imaging and the materials science in both fabrication and characterization. The structured characteristics of the structure light need materials also with structured optical properties that can generate or manipulate structured light in a straightforward way, which can be well satisfied by liquid crystals, a soft mater that can self‐assemble into tunable ordered structures through external stimuli. This review summarizes the research progress of the liquid crystal‐based devices used in structured light generations and modulations, including the well‐established techniques in the market, like the spatial light modulator, q‐plate and the liquid crystal integrated optical metasurfaces. Especially, light‐matter interactions are discussed from the topological view of both the structured light and the liquid crystal structures. Such a perfect matching in topology makes the liquid crystal a promising star together with structured light in future optic and photonic technologies. [ABSTRACT FROM AUTHOR]

Circularly polarized luminesce (CPL) materials are crucial for various applications, including display devices and bionics. However, existing CPL materials face difficulties in simultaneously meeting large luminescence asymmetry factors (glum), high photoluminescence quantum yields (PQY), and long lifetime. Here, a simple strategy to prepare a series of high‐performance CPL liquid crystal copolymers is constructed by triplet–singlet Förster‐resonance energy transfer (TS‐FRET). A series of chiral liquid crystal copolymers are successfully synthesized by copolymerizing phosphorescent donor bearing chiral cholesterol mesogen with fluorescence acceptor bearing naphthalimide chromophore. The introduction of the naphthalimide component promotes the formation of twist grain boundary smectic‐A phase (TGBA*) and behaves distinctive selective reflective effect. An effective TS‐FRET process occurs in the two components of copolymers, and dual emission characteristics of thermally activated delayed fluorescence and room‐temperature phosphorescence are observed in the copolymer films. When the naphthalimide content of copolymer is 10%, the luminescence lifetime can achieve 83.0 ms. As the naphthalimide content increases, the glum initially increases and subsequently decreases, reaching a maximum of −1.15. In addition, the copolymer films possess enhanced photoluminescence quantum yield by TS‐FRET with a maximum value of 68%. The application of copolymers in information security is also explored. [ABSTRACT FROM AUTHOR]

Liquid crystal films play a key role in advancing next-generation optical and photonic devices that require a precise in-plane modulation of optical anisotropy. This study employs multiphoton direct laser writing, a high-resolution three-dimensional (3D) printing method, to fabricate pseudoperiodic patterns of lines and grooves on glass surfaces for the in-plane alignment of liquid crystal films. Single layers of lines with submicron thickness and line spacing were fabricated in less than half an hour and forced the in-plane alignment of a liquid crystal film with a thickness of about 10 μm. We validate the method on patterns with singular topologies designed to induce the nucleation of disclination defects with a predetermined spatial arrangement, orientation, and topological strength. Compared to other surface patterning methods, high-resolution 3D printing provides the unique advantage of direct surface fabrication, enabling the creation of nonflat geometries such as terraces and lenses and expanding the design and functionalities of liquid crystal devices. We anticipate that this method will be used to create thin-film devices such as polarization gratings, beam steerers, and q-plates for manipulating polarized and structured light. [ABSTRACT FROM AUTHOR]

A novel room‐temperature liquid crystal of tetraphenylethylene derivative (TPE‐DHAB) was synthesized using an ionic self‐assembly strategy. The TPE‐DHAB complex exhibits typical aggregation‐induced emission properties and a unique helical supramolecular structure. Moreover, the generation and handedness inversion of circularly polarized luminescence (CPL) can be achieved through further chiral solvation, providing a facile approach to fabricate room‐temperature liquid crystalline materials with controllable supramolecular structures and tunable CPL properties through a synergistic strategy of ionic self‐assembly and chiral solvation process. [ABSTRACT FROM AUTHOR]

Aiming at the problem of limited transmission energy of liquid crystal tunable filter (LCTF), a dual-wavelength transmission system with high signal-to-noise ratio (SNR) is proposed in this paper. The proposed transmission factor Qp is the main influence on the number and location of transmission wavelengths as well as the bandwidth of each transmission wavelength for dual-wavelength systems. Dual-wavelength LCTF can improve the effective transmission energy of the system by increasing the number of filtering channels, and the transmission energy can be increased by about 1.8 times and 70% at short and long wavelengths, respectively, which improves the signal-to-noise ratio (SNR) of the system. Moreover, the dual-wavelength LCTF system is even possible to increase the transmission energy by about 7% at a 33% increase in spectral resolution. Therefore, the dual-wavelength LCTF transmission method not only can improve the SNR of target detection with dual-wavelength response features, but also can effectively solve the problem of contradiction between spectral resolution and spectral transmission energy. [ABSTRACT FROM AUTHOR]

The electroconvection of liquid crystals is a typical example of a dissipative structure generated by complicated interactions between three factors: convective flow, structural deformation, and the migration of charge carriers. In this study, we found that the periodic structural deformation of a cholesteric liquid crystal propagates in space, like a wave, under an alternating-current electric field. The existence of convection and charge carriers was confirmed by flow-field measurements and dielectric relaxation spectroscopy. Given that the wave phenomenon results from electroconvection, we suggest a possible model for describing the mechanism of wave generation. The validity of the model was examined using the Onsager variational principle. Consequently, it was suggested that wave generation can be described by four effects: the electrostatic potential, mixing entropy, anisotropic friction due to charge migration, and viscous dissipation of the liquid crystal. [ABSTRACT FROM AUTHOR]

The geometric shape, symmetry, and topology of colloidal particles often allow for controlling colloidal phase behavior and physical properties of these soft matter systems. In liquid crystalline dispersions, colloidal particles with low symmetry and nontrivial topology of surface confinement are of particular interest, including surfaces shaped as handlebodies, spirals, knots, multi-component links, and so on. These types of colloidal surfaces induce topologically nontrivial three-dimensional director field configurations and topological defects. Director switching by electric fields, laser tweezing of defects, and local photo-thermal melting of the liquid crystal host medium promote transformations among many stable and metastable particle-induced director configurations that can be revealed by means of direct label-free three-dimensional nonlinear optical imaging. The interplay between topologies of colloidal surfaces, director fields, and defects is found to show a number of unexpected features, such as knotting and linking of line defects, often uniquely arising from the nonpolar nature of the nematic director field. This review article highlights fascinating examples of new physical behavior arising from the interplay of nematic molecular order and both chiral symmetry and topology of colloidal inclusions within the nematic host. Furthermore, the article concludes with a brief discussion of how these findings may lay the groundwork for new types of topology-dictated self-assembly in soft condensed matter leading to novel mesostructured composite materials, as well as for experimental insights into the pure-math aspects of low-dimensional topology. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers have shown an attractive potential for various biological applications due to their unique combination of mechanical flexibility and responsiveness to external stimuli. In this review, we will focus on a few examples of LCEs used with specific applications for biological/biomedical/environmental systems. So far, areas of innovation have been concentrating on the integration of LCEs to enhance stability under physiological conditions, ensure precise integration with biological systems, and address challenges related to optical properties and spatial control of deformation. However, several challenges and limitations must still be addressed to fully realize their potential in biomedical and environmental fields, and future research should focus on continuing to improve biocompatibility, response to the environment and chemical cues, mechanical properties, ensuring long-term stability, and establishing cost-effective production processes. So far, 3D/4D printing appears as a great promise to develop materials of high complexity, almost any shape, and high production output. However, researchers need to find ways to reduce synthesis costs to ensure that LCEs are developed using cost-effective production methods at a scale necessary for their specific applications' needs. [ABSTRACT FROM AUTHOR]

Current liquid crystal (LC) lenses cannot achieve lossless arbitrary movement of the optical axis without mechanical movement. This article designs a novel bottom electrode through simulation and optimization, which forms a special LC lens with an Archimedean spiral electrode, realizing a 3D LC wedge and an arbitrarily movable LC lens. When only the bottom electrode is controlled, it achieves a maximum beam steering angle of 0.164°, which is nearly an order of magnitude larger than the current design. When the top and bottom electrodes are controlled jointly, a 0.164° movement of the lens optical axis is achieved. With focal length varies, the movement of the optical axis ranges from zero to infinity, and the lens surface remains unchanged during movement. The focus can move in a 3D conical area. When the thickness of the LC layer is 30 μm, the fastest response time reaches only 0.635 s, much faster than now. [ABSTRACT FROM AUTHOR]

Background/Objectives: This review examines the evolution of lyotropic liquid crystals (LLCs) in ocular drug delivery, focusing on their ability to address the challenges associated with traditional ophthalmic formulations. This study aims to underscore the enhanced bioavailability, prolonged retention, and controlled release properties of LLCs that significantly improve therapeutic outcomes. Methods: This review synthesizes data from various studies on both bulk-forming LLCs and liquid crystal nanoparticles (LCNPs). It also considers advanced analytical techniques, including the use of machine learning and AI-driven predictive modeling, to forecast the phase behavior and molecular structuring of LLC systems. Emerging technologies in biosensing and real-time diagnostics are discussed to illustrate the broader applicability of LLCs in ocular health. Results: LLCs are identified as pivotal in promoting targeted drug delivery across different regions of the eye, with specific emphasis on the tailored optimization of LCNPs. This review highlights principal categories of LLCs used in ocular applications, each facilitating unique interactions with physiological systems to enhance drug efficacy and safety. Additionally, novel applications in biosensing demonstrate LLCs' capacity to improve diagnostic processes. Conclusions: Lyotropic liquid crystals offer transformative potential in ocular drug delivery by overcoming significant limitations of conventional delivery methods. The integration of predictive technologies and biosensing applications further enriches the utility of LLCs, indicating a promising future for their use in clinical settings. This review points to continued advancements and encourages further research in LLC technology to maximize its therapeutic benefits. [ABSTRACT FROM AUTHOR]

The figure-of-merit (FoM) is a crucial metric in evaluating liquid crystal (LC) phase shifters, significantly influencing the selection of superior device candidates. This paper identifies, for the first time, a fundamental limitation in the widely-used High-Frequency Structure Simulator (HFSS), a closed-source commercial tool, when modeling reconfigurable delay line phase shifters (RDLPS) based on LC at millimeter-wave (mmW) frequencies for Beyond 5G (B5G) and Sixth-Generation (6G) applications. Specifically, the study reveals unreliable predictions of differential phase shifts (DPS) when using the line length parameterization (LLP) approach, with an accuracy of only 47.22%. These LLP-induced inaccuracies lead to misleading FoM calculations, potentially skewing comparative analyses against phase shifters implemented with different geometries or advanced technologies. Additionally, the per-unit-length (PUL) paradigm, commonly employed by microwave circuit engineers for evaluating and optimizing microwave transmission line designs, is also found to have limitations in the context of mmW RDLPS based on LC. The PUL methodology underestimates the FoM by 1.38206°/dB for an LC coaxial RDLPS at 60 GHz. These findings underscore a critical symmetry implication, where the assumed symmetry in phase shift response is violated, resulting in inconsistent performance assessments. To address these challenges, a remediation strategy based on a scenario-based "Length-for-π" (LFP) framework is proposed, offering more accurate performance characterization and enabling better-informed decision-making in mmW phase shifter design. [ABSTRACT FROM AUTHOR]

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The current investigation conducts a thorough analysis of the nonlinear optical properties, binding characteristics, and electronic features of 1‐proplene‐3‐methylimidazolium (PMIM)‐X ionic liquid (IL) crystal. These findings reveal that the dissociation energy of PMIM‐X indicates a preference for ionic dissociation over neutral dissociation. Notably, the ionic dissociation energy shows an increasing trend with both the electron affinity (EA) and the size of X. In the process of forming the IL crystal PMIM‐X, this study observes a charge transfer from PMIM to X species. It is noteworthy that the extent of charge transfer intensifies with the increasing size of X. Additionally, the calculated energy gap exhibits a positive correlation with both EA and the size of X. Although these results suggest promising nonlinear optical behavior for PMIM‐X, it is crucial to acknowledge the limitations of the study. All calculations are conducted on single atoms in the gas phase, overlooking potential effects that may arise in the liquid phase or bulk conditions. Therefore, future investigations should consider these factors for a more comprehensive understanding of the behavior of PMIM‐X in practical applications. [ABSTRACT FROM AUTHOR]

In this study the dielectric properties are experimentally studied and also analyzed the influence of guest particles on the functional properties of various liquid crystals. The polar and elastic energy of the nanoparticles is found to affect the functional energy of pure suspension. In addition to this, the functional dielectric anisotropy of the dispersed system takes modified form. In this study experiments are performed on various materials to find dielectric anisotropy and also found in good agreement with theoretical explanation. [ABSTRACT FROM AUTHOR]