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Entanglement in a soft condensed matter system is enabled in the form of entangled disclination lines by using colloidal particles in nematic liquid crystals. These topological excitations are manifested as colloidal entanglement at equilibrium. How to further utilize nonequilibrium disclination lines to manipulate colloidal entanglement remains a nontrivial and challenging task. In this work, we use experiments and simulations to demonstrate the reconfigurations of nematic colloidal entanglement in light-driven spatiotemporal evolutions of disclination lines. Colloidal entanglement can sense subtle changes in the topological structures of disclination lines and realize chirality conversion. This conversion is manifested as the "domino effect" of the collective rotation of colloids in the disclination lines. By programming the topological patterns and the geometry of the disclination lines, colloidal entanglement can be assembled and split. More remarkably, a double-helix entangled structure can be formed by controlling the changes in the morphology of the disclination lines. Thus, this work will provide opportunities to program colloidal composites for smart materials and micromachines. [ABSTRACT FROM AUTHOR]

Smart surfaces, distinguished by their dynamic responses to environmental changes, may enhance the functionality, interactivity, and efficiency of materials and devices. Liquid crystal elastomers (LCEs) are ideal candidates for creating smart surfaces, allowing reversible topographical changes in response to environmental stimuli. However, traditional thermoset LCE preparation methods require complex manufacturing processes, including photopolymerization, and the resulting surfaces (often pillars) are nonreprogrammable and nonrecyclable. In this work, hot embossing is used in combination with a thermoplastic LCE for creating self‐healing and reprogrammable exotic surfaces capable of reversibly responding to environmental stimuli, significantly simplifying fabrication. It is demonstrated that hot embossing can be effectively applied to fabricate surfaces with arrays of pillars, cones, tubes, or mushroom shapes. The exotic surface structures exhibit reversible and programmable shape changes in response to heat and can be erased and rewritten to alternate complex topographies. As an additional feature, the LCE can be recycled and reused to create photo‐responsive surface topographies that can be spatiotemporally addressed by light. Light‐responsive LCE surfaces are prepared by incorporating a photothermal dye without loss of reconfigurability. Demonstrators are fabricated such as locally controlled object movement on a surface by light. [ABSTRACT FROM AUTHOR]

The introduction of liquid crystals into microcavities has garnered considerable attention for their exceptional tunability and high sensitivity to external perturbation factors within their distinct phase states. Here, a novel light source with both wavelength tunability and an exceptionally narrow linewidth is presented. This innovation is realized by strategically manipulating LC molecules, transitioning them from a well‐aligned state to a disordered state with increasing temperature. The microcavity is tailored to support bound states in the continuum, a cutting‐edge concept in photonic research that allows for light localization with minimal loss. In the pursuit of potential biocompatibility and to reduce cytotoxicity, indium phosphide colloid quantum dots are opted to serve as the emissive carriers within the system. An ultra‐narrow linewidth light emission of 0.039 nm is observed, corresponding to a quality factor reaching 16668, along with a tunable range of 1.21 nm and a temperature sensitivity of 33.52 pm K−1. The invention's compact size and tunable character make it an ideal candidate for a variety of potential applications, such as eco‐friendly sensors with minimal ecological impact, optical modulators with precise control over light, and adaptable photonic devices that can be integrated with a diverse array of materials and configurations. [ABSTRACT FROM AUTHOR]

Hybrid Organic‐Inorganic Halide Perovskites (HOIHPs) represent an emerging class of semiconducting materials, widely employed in a variety of optoelectronic applications. Despite their skyrocket growth in the last decade, a detailed understanding on their structure–property relationships is still missing. In this communication, we report two unprecedented perovskite‐like materials based on polyfluorinated imidazolium cations. The two materials show thermotropic liquid crystalline behavior resulting in the emergence of stable mesophases. The manifold intermolecular F ⋅ ⋅ ⋅ F interactions are shown to be meaningful for the stabilization of both the solid‐ and liquid‐crystalline orders of these perovskite‐like materials. Moreover, the structure of the incorporated imidazolium cation was found to tune the properties of the liquid crystalline phase. Collectively, these results may pave the way for the design of a new class of halide perovskite‐based soft materials. [ABSTRACT FROM AUTHOR]

Liquid crystalline (LC) materials are especially suited for the preparation of active three-dimensional (3D) and 4D microstructures using two-photon laser printing. To achieve the desired actuation, the alignment of the LCs has to be controlled during the printing process. In most cases studied before, the alignment relied on surface modifications and complex alignment patterns and concomitant actuation were not possible. Here, we introduce a strategy for spatially aligning LC domains in three-dimensional space by using 3D-printed polydimethylsiloxane-based microscaffolds as confinement barriers, which induce the desired director field. The director field resulting from the boundary conditions is calculated with Landau de Gennes theory and validated by comparing experimentally measured and theoretically predicted birefringence patterns. We demonstrate our procedures for structures of varying complexity and then employed them to fabricate 4D microstructures that show the desired actuation. Overall, we obtain excellent agreement between theory and experiment. This opens the door for rational design of functional materials for 4D (micro)printing in the future. [ABSTRACT FROM AUTHOR]

This paper presents interactive liquid crystal fiber arrays that can actuate in a way perceptible by human touch. The fibers are actuated via a computer interface, enabling precise control over actuation direction, magnitude, and frequency. Unlike conventional methods, our technique initiates the actuation at the base of the fibers, which is enabled by fabricating the fibers directly onto an electrical circuit. Fiber actuation is achieved by localized addressing of an in situ formed radially aligned segment. This induces reduction in the scalar order parameter and leads to deformation of the fiber base, causing bending toward the activated region. Extensive modeling validates this actuation mechanism and identifies optimal conditions and actuation strategies for achieving the desired responses. The actuation process is rapid, is highly reversible, and maintains excellent performance over repeated (>200) cycles. These liquid crystal fiber arrays provide a safe contact with humans or other objects, making them highly suitable for applications in smart wearable devices and immersive interfaces. [ABSTRACT FROM AUTHOR]

Constructing self‐adaptive oscillators that can continuously, stably, and tunably transform external stimulus into mechanical work is high demand for soft robots, energy harvesters and object conveyors. However, these systems are challenging to develop because of the single mesogenic anisotropy and simple material constituents obtained by a traditional technique. Here, a photoactivated self‐adaptive liquid crystal elastomer (LCE) oscillator with controlled nanoassembly‐directed hierarchically anisotropic structure is demonstrated by developing the highly‐aligned silver nanowire (AgNW) assemblies (HAs) to guide the orientation and polymerization of LC molecules. The fabricated HAs‐LCE film exhibits tunable multiple anisotropies on mesogenic alignment, composition, density gradient across the thickness and mechanical behaviors. Combined with excellent photo‐driven bending deformation, the HAs‐LCE cantilever performs a self‐sustained, periodic and steady oscillation self‐propelled by negative feedback loops under a continuous NIR laser. Impressively, triggered by synergetic deformations of anisotropically responsive architecture, self‐adaptive oscillations are first achieved with self‐tunable frequencies spanning from 4.1 to 13.2 Hz to accommodate variable light intensity, showing enormous and distinctive potentials for optical modulation. [ABSTRACT FROM AUTHOR]

Multidimensional solitons are prevalent in numerous research fields. In orientationally ordered soft matter system, three-dimensional director solitons exemplify the localized distortion of molecular orientation. However, their precise manipulation remains challenging due to unpredictable and uncontrolled generation. Here, we utilize preimposed programmable photopatterning in nematics to control the kinetics of director solitons. This enables both unidirectional and bidirectional generation at specific locations and times, confinement within micron-scaled patterns of diverse shapes, and directed propagation along predefined trajectories. A focused dynamical model provides insight into the origins of these solitons and aligns closely with experimental observations, underscoring the pivotal role of anchoring conditions in soliton manipulation. Our findings pave the way for diverse fundamental research avenues and promising applications, including microcargo transportation and optical information processing. [ABSTRACT FROM AUTHOR]

The development of a Spectrally Programmable Liquid‐State Active System for High‐performance (SPLASH) is introduced, which allows for multicolor lasing and White Emission. This completely liquid, three‐phase device showcases exceptional tunability within a singular Liquid Crystal Cell (LCC). Components include a Coumarin 540 (CM540)‐doped liquid crystal (LC) mesophase, an ionic liquid (RTIL) richly endowed with Rhodamine 6G (R6G) dye, and a Stilbene 420 (SB420)‐infused water‐based solution. This device displays significant accomplishments in multicolor tunability through the use of both lasing and fluorescence mechanisms. As a result, White Light Fluorescence (WFluo) and White Light Hybrid‐Emission (WHE) are showed, which consist of two lasing bands and one fluorescence. This is achieved in a liquid‐state environment characterized by phase separation and careful device management. Additionally, due to its fluid‐like nature and compact design, the device inherently offers considerable scalability — since its components can be easily adjusted and rearranged. This approach promises ground‐breaking advancements in high‐impact applications such as the Li‐Fi concept. Therefore, SPLASH stands out as an innovative platform for White Light Fluorescence (WFluo) and Multicolor Lasing (ML) within liquid‐state active systems. [ABSTRACT FROM AUTHOR]

Organic optical waveguide materials have attracted considerable attention for their promising applications in photonic and optoelectronic devices. However, for most materials, excellent light‐loss properties at high temperature cannot be obtained due to many factors. Consequently, realizing efficient optical waveguide materials that perform well at elevated temperatures remains a significant challenge. In this study, relying on the luminescent properties and self‐assembly properties of luminescent liquid crystals (LLCs), successfully fabricated materials are present for highly efficient active optical waveguides. A systematically synthesized set of LLCs with different structures is named according to the substituent type and the position of the cyano group, namely α‐DECN, α‐DEEOCN, β‐DECN, and β‐DEEOCN. Notably, α‐DECN and β‐DECN reveal hexagonal columnar phase, while α‐DEEOCN and β‐DEEOCN exhibit smectic phase. Optical waveguide experiments have revealed that the obtained LLCs showed highly efficient optical waveguide behavior, where the lowest light loss reached 0.15 dB mm−1 at room temperature. Remarkably, these LLCs show even lower light loss at high temperatures, with the light loss reaching 0.11 dB mm−1 as the lowest point. Further experimental results indicate that this phenomenon is attributed to the change in the dipole moment of these molecules. This research forms a significant groundwork for advanced exploration in optical waveguide material. [ABSTRACT FROM AUTHOR]

Cyclotriphosphazene (CP) is a cyclic inorganic compound with the chemical formula N3P3. This unique molecule consists of a six‐membered ring composed of alternating nitrogen and phosphorus atoms, each bonded to two chlorine atoms. CP exhibits remarkable versatility and significance in the realm of materials chemistry due to its easy functionalization via facile nucleophilic substitution reactions in mild conditions as well as intriguing properties of resultant final CP‐based molecules or polymers. CP has been served as an important building block for numerous functional materials. This review provides a general and broad overview of the synthesis of CP‐based small molecules through nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), and their applications, including flame retardants, liquid crystals (LC), chemosensors, electronics, biomedical materials, and lubricants, have been summarized and discussed. It would be expected that this review would offer a timely summary of various CP‐based materials and hence give an insight into further exploration of CP‐based molecules in the future. [ABSTRACT FROM AUTHOR]

Spiral phase contrast imaging alleviates the information load by extracting the geometric features of objects and is one of the most representative branches of instant imaging processing. The self-healing capacity of edge detectors can enhance their robustness to obstacles in practical applications. Here, a self-healing spiral phase contrast imaging scheme is proposed and experimentally demonstrated by a liquid crystal edge detector combining a spiral phase, an axicon phase, and a lens phase. The spiral phase is encoded into a liquid crystal by photopatterning. Self-healing contrast imaging is characterized by a series of edge images of both high-contrast amplitude-type and low-contrast phase-type objects. This work extends the self-healing capacity of these detectors to instant imaging processing and paves the way for optical applications with self-healing features. [ABSTRACT FROM AUTHOR]

The fabrication of materials that can switch between circularly polarized luminescence (CPL) signals is both essential and challenging. Here, two new halogen‐bonded fluorescent molecular photoswitches, namely, HB‐switch 1 and HB‐switch 2, containing α‐cyano‐substituted diarylethene compounds with different end groups were developed. Upon exposure to specific UV or visible light wavelengths, they exhibited controllable and reversible Z/E photoisomerization. When these switches were integrated into blue‐phase liquid crystals (BPLCs), the temperature range of BP significantly expanded. Notably, the BP system incorporating HB‐switch 1 exclusively achieved reversible polarization inversion of CPL signals under irradiation with specific UV/Visible light and during cooling/heating. The photo/thermal dual‐response behavior of the CPL signals can be attributed to the phase transition from a high‐symmetry 3D BP Icubic lattice to a low‐symmetry 1D helical superstructure induced by the Z/E photoisomerization of HB‐switch 1 and temperature changes. This study underscores the significance of employing halogen‐bond assembly strategies to design materials with switchable CPL signals, opening new possibilities for CPL‐active systems. [ABSTRACT FROM AUTHOR]

Circularly polarized luminescence (CPL) materials are highly demanded due to their great potential in optoelectronic and chiroptical elements. However, the preparation of CPL films with high luminescence dissymmetry factors (glum) remains a formidable task, which impedes their practical application in film‐based devices. Herein, a facile strategy to prepare solid CPL film with a high glum through exogenous chiral induction and amplification of liquid crystal polymers is proposed. Amplification and reversion of the CPL appear when the films are annealed at the chiral nematic liquid crystalline temperature and the maximal glum up to 0.30 due to the enhancement of selective reflection. Thermal annealing treatment at different liquid crystalline states facilitates the formation of the chiral liquid phase and adjusts the circularly polarized emission. This work not only provides a straightforward and versatile platform to construct organic films capable of exhibiting strong circularly polarized emission but also is helpful in understanding the exact mechanism for the liquid crystal enhancement of CPL performance. [ABSTRACT FROM AUTHOR]

The terahertz spectral region, which bridges between electronics and optics, is poised to play an important role in the development of transformative wireless communication and imaging systems with unprecedented functionality. Currently, a major challenge in terahertz technology is to develop high‐performance terahertz beam‐forming devices that can dynamically shape the terahertz radiation in a flexible manner. Existing terahertz beam‐forming devices have limited coding bits, field‐of‐view, and beam gain. Here, a reconfigurable liquid crystal‐integrated terahertz metasurface is experimentally demonstrated, with each metasurface unit cell being independently addressable. The metasurface has a 260° continuous phase tuning range with a liquid crystal layer thickness of only 1% of the free‐space wavelength. The terahertz wave diffracted from the metasurface can be steered toward a wide range of directions is shown, covering a record‐large 110° field‐of‐view with a peak gain of 25 dBi. The metasurface also features a low power consumption and sub‐second switching time. Furthermore, the formation of multiple terahertz beams is demonstrated, with the direction of each beam and the power ratio between beams adjustable on demand. The proposed liquid crystal metasurface possesses compelling prospects for future terahertz communication and imaging applications. [ABSTRACT FROM AUTHOR]

As a powerful platform for next‐generation display, planar liquid crystal (LC) optics exhibit attractive properties such as electro‐optical response, high efficiency, and broadband tunability. With planar LC optics applications taking off, multidimensional modulation and multiplexing capability of light wave is becoming crucial. Here, a Pancharatnam‐Berry phase LC hologram is demonstrated that enables the multidimensional modulation of amplitude, phase, and polarization of light, which increases the degree of freedom of multiplexing display to 4 at a single wavelength, realizing the simultaneous decoupling modulation in dual polarization channels in near and far fields. According to the quaternary degeneracy characteristics of the orientation angle of LC molecules implied in Malus' law, the LC holograms are designed using the optimized Gerchberg‐Saxton and annealing algorithms, and it is demonstrated that the spatial and polarization multiplexing of LC holograms have remarkable wavelength‐dependent electrical tunability. This LC hologram paves a promising pathway toward multifunctional LC optics for advanced display and imaging. [ABSTRACT FROM AUTHOR]

With the advantages of parallel processing, high‐speed operation, and ultra‐low power consumption, optical computing presents immense potential in this age of information explosion. As a fundamental optical computing component, optical differentiator has extensive applications, particularly excelling in the real‐time processing and recognition of high‐frame‐rate image information. An ideal optical differentiator needs to adapt to different application scenarios, such as arbitrary operating wavelengths, complex or even transparent targets. Furthermore, performing differential operations of varying orders on target optical field can extract multi‐level information. Unfortunately, most current differential computing devices can only meet part of the requirements, which limits the attained information dimensions and hinders the development of their practical application. Herein, a universal platform based on liquid crystals (LCs) is proposed to achieve 0th‐, 1st‐, and 2nd‐order differential operations of amplitude‐typed or even phase‐typed objects within a broadband range. The switching of different differentiation orders can be accomplished by straightforward adjusting the applied voltages of the differentiator. This approach is capable of extracting more feature information including bright‐field, outline, and edges images of versatile targets. With advanced characteristics of multi‐dimension, broadband and multifunction, the work can flourish applications in fields of image processing, biomedical imaging and optical analog computation, etc. [ABSTRACT FROM AUTHOR]

The study is focused on the flow parameters of the slotted impinging jet associated with its heat transfer performance. The analysis is performed for the circular and slotted jets of square, cross, and oval sections for flow outlet to target plate distance of L/D = 1 to 4. The Reynolds number range of 12700 - 23000 is used in this study to analyze the heat transfer pattern using liquid crystal sheet. The numerical analysis is carried out using CFD. The axial velocity peak (u/U0 = 2.124) is observed for the square jet corresponding to r/D = 0.33 at L/D = 1 and the peak reduces with increasing L/D distances. Higher intensity of average radial velocity (ur/U0 = 1.44) is observed close to the impinging plate for the slotted jet at L/D = 1 at 0.5 = r/D = 1.4 compared with radial velocity (ur/U0 = 0.91) of circular jet. Nusselt number distribution has little dependence for circular jet on the separation distance as the variation is marginal at L/D = 4 when compared to L/D = 1 and 2, the slotted jet however shows marked variation of Nusselt number (136.8 at L/D = 1, 135.2 at L/D = 2 and 113.5 at L/D = 4) in the region at X/D = 1.5. The highest values of turbulence intensity (TI = 0.206) is observed at r/D = 0.5 for the square jet at L/D = 3. [ABSTRACT FROM AUTHOR]

Two series of unsymmetric α-cyanostilbene-based tetracatenars containing three hexadecyl chains at one end and one alkyl chain with varying lengths at the other end were prepared by using Suzuki coupling and Knoevenagel reactions. These tetracatenars with the terminal three hexadecyl chains, which are adjacent to the cyano group are non-mesogens, whereas the isomers with one alkyl chain, which is adjacent to the cyano group display transition from non-mesogens to monotropic hexagonal columnar liquid crystal upon elongation of the alkyl chain. This transition could be attributed to that the three hexadecyl chains which are adjacent to the cyano group decrease the interactions between π-conjugated rigid cores, hindering the formation of mesophase. In addition, weak slovatochromism implies weak ICT in both series tetracatenars. Both series isomers exhibit distinct AIE characteristics attributing to the presence of α-cyanostilbene, which could induce stereoisomerism and restricted intermolecular rotation in the aggregated state. Different mechanochromism behaviors could be achieved due to the positional isomerism of terminal alkyl chains. Therefore, tuning the position of terminal alkyl chains could give rise to distinct changes in the molecular aggregate, which provides a scheme to build multifunctional materials with diverse potentials. [ABSTRACT FROM AUTHOR]

An ultrasensitive temperature sensor based on photonic crystal fiber (PCF) filled with liquid crystal and nanogold rods using surface plasmon resonance (SPR) is numerically analyzed in this paper. Gold is selected as a plasmonic metal to excite the SPR phenomenon. This paper shows a comparative study and inspects the effect of temperature sensing performance between one big gold rod and lattice of nanoscale gold rods. A finite element method (FEM) using COMSOL software has been applied for the investigation of some propagation characteristics of the PCF sensor. From the numerical results, it is observed that introducing an array of nanoscale gold rods helps to obtain high temperature sensitivity. After watchful investigation, the maximum sensitivities of 23 nm/°C have been achieved as the temperature changes from 30 °C to 40 °C. Compared with some previously reported temperature sensors, our proposed temperature sensor shows excellent sensitivity performances. [ABSTRACT FROM AUTHOR]

Phase-shifting speckle interferometry could achieve full-field deformation measurement of rough surfaces. To meet the dynamic requirement and further improve the accuracy, a two-step synchronous phase-shifting measurement system is established based on the polarization-sensitive phase modulation ability of a liquid crystal spatial light modulator; by multiplexing the reference wavefront, an accurate phase shift is generated between two independent recording channels, and a common-path self-reference vortex interference structure is built for precise spatial registration. Meanwhile, according to the speckle statistical principle, a novel two-frame phase-shifting algorithm as well as a two-step spatial registration strategy is presented to strengthen the robustness of intensity and position differences caused by spatial-multiplexing; thereby, accurate transient deformation can be directly obtained from phase-shifting speckle interferograms recorded before and after deformation. The effectiveness and accuracy of the proposal are validated from the out-of-plane deformation measurement experiment by comparing with the traditional two-step and four-step phase-shifting methods. The dynamic ability is exhibited through reconstructing mechanical and thermal deformations across various application scenarios. [ABSTRACT FROM AUTHOR]

A layered heterogeneous structure (LHS), consisting of silver, liquid crystal, and nonlinear dielectric layers, is proposed to realize functions of computing and sensing. By leveraging the optical Tamm state, the intrinsic absorption principle of liquid crystal, and nonlinear effects, the design of an integrated device capable of passive multiplication and division operations, along with high-performance multi-physical quantity sensing functionalities, is achieved. The given LHS exhibits Janus properties, with different physical functions manifested depending on the direction of electromagnetic wave (EW) propagation. During forward propagation of EWs, the LHS displays high and sharp absorptivity peaks at 774.8 and 1517.6 nm. The relationship between the two peaks approximates a frequency multiplication factor of 1.960, enabling signal multiplication. Furthermore, the two absorptivity peaks at different wavelengths facilitate the sensing of serum creatinine solution concentration and external pressure, with sensitivity (S), quality factors (Q), and figure of merit (FOM) of 266.76 μmol L−1/nm and 213.33 GPa/nm, as well as 248.76 and 348.22, 84.1 L (μmol)−1 and 49.06 GPa−1, respectively. During backward propagation of EWs, absorptivity peaks with distinct resolutions are observed at 1423 and 2809 nm, with a multiple relationship between them of 1.974, enabling frequency doubling for signal division. Additionally, the absorptivity curve facilitates temperature sensing over a wide range from 257 to 347 K. Owing to the unique temperature S of liquid crystal, different sensitivities and resolutions are observed at 257 to 297 K and 307 to 347 K, with S of 1.015 and 0.686 K/nm, and corresponding Q and FOM of 21.57 and 12.576, 0.076 K−1 and 0.003 04 K−1, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a metastructure device (MSD) modulated by liquid crystal (LC) and vanadium dioxide (VO2), suitable for circular-to-linear polarization conversion and refractive index (RI) sensing. The MSD employs a 2 × 2 array as a unit cell, forming a circular-to-linear polarization conversion. Filling the MSD with analytes of different RIs can cause changes in the electromagnetic properties of the MSD, thus realizing the sensing function. Furthermore, the detection range of the sensing can be modified by changing the long-axis pointing of the LC molecules under an applied voltage, resulting in multi-range detection. The RI unit is denoted as RIU. Without an applied voltage, the RI detection range is 1.949–2.607, with a sensitivity of 199 GHz/RIU; under full-bias conditions, the detection range is 2.828–3.391, with a sensitivity of 143 GHz/RIU. In the initial state of LCs, this paper also explores the use of the phase transition of VO2 to adjust the conductivity of VO2 to achieve changes in the detection range. In the insulating state, the detection range is 2.12–2.607, with a sensitivity of 225 GHz/RIU, while in the metallic state, the detection range is 1–2, with a sensitivity of 183 GHz/RIU. Furthermore, altering the thickness of the analyte also affects the electromagnetic properties of the device, causing a shift in the peak axial ratio frequency, making the MSD suitable for analyte thickness detection. The MSD has a wide detection range, high sensitivity, and adaptability, making it suitable for identifying cancer cells and giving a new method of monitoring human health. [ABSTRACT FROM AUTHOR]

As a green and safe amino acid surfactant, sodium lauryl glutamate (SLG) has been favored by researchers. However, SLG has low solubility and its single system is not conducive to its application. Zwitterionic surfactants can increase its solubility by forming mixed micelles and possibly new phase states. In this paper, SLG was combined with lauramide propyl hydroxysulfobetaine (LHSB), and its different states were characterized. The type of phase states were determined and the pseudo-ternary phase diagrams were drawn. It was found that when the concentration of SLG was low and the proportion of SLG was not high, there were a large number of globular micelles in the solution, and rod-like micelles would appear as the concentration increased. As the concentration further increased, the SLG/LHSB system exhibited the characteristic of worm like micelles. With the further increase of concentration, the liquid crystal structures of hexagonal and layered phases were observed. [ABSTRACT FROM AUTHOR]

The surface activity of potassium heptylene decyl succinate (PHDS) at water-air interface was studied. The obtained results showed a very good correlation between the surface activity of PHDS and concentration of surfactant solutions and temperature of the system. The phase behaviour and structure of aggregates in PHDS)/water binary system were investigated. The phase diagram of the PHDS/water binary system was obtained depending on the concentration of components and temperature of the system. It was established that due to the double hydrocarbon chain of the PHDS molecule, the lamellar liquid crystalline phase exists across a wide range of the phase diagram. It was shown that upon the addition of water, the cross-sectional area of the PHDS molecules in lamellar liquid crystals is changed insignificantly. This result was associated with the invariability of the distance of the lipophilic layers of formed lamellar liquid crystals by PHDS molecules. On the basis of video-enhanced microscopic studies, it was established that in two-phase region of the phase diagram, lamellar liquid crystals coexist with water in the form of vesicles. [ABSTRACT FROM AUTHOR]

Synthesis, structural and photoluminescence studies of p-(n-heptyl) benzoic acid (7ba) liquid crystalline (LC) compound with the homogeneous dispersion of ZnO nanoparticles (NPs) in different weight concentrations (i.e., 1–2.5 wt.%) were undertaken. The synthesized samples were subsequently characterized by different characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-Vis) spectroscopy, differential scanning calorimetry (DSC), optical polarising microscopy (POM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy. From the XRD studies, the diff raction peaks observed were well resolved indicating the presence of ZnO NPs. The particle size was found to be 60 nm. SEM studies revealed the uniform dispersion and the presence of ZnO NPs in the LC samples. From the DSC analysis, the temperatures at which the phase changes take place and the corresponding enthalpy values were estimated. FTIR spectra gave information about the various functional groups present in the samples. PL studies showed the peak at 663 nm due to the presence of point defects within the bandgap-like vacancies and interstitials known as deep-level emission. [ABSTRACT FROM AUTHOR]

This review explores the integration of graphene and liquid crystals to advance sensor technologies across multiple domains, with a focus on recent developments in thermal and infrared sensing, flexible actuators, chemical and biological detection, and environmental monitoring systems. The synergy between graphene's exceptional electrical, optical, and thermal properties and the dynamic behavior of liquid crystals leads to sensors with significantly enhanced sensitivity, selectivity, and versatility. Notable contributions of this review include highlighting key advancements such as graphene-doped liquid crystal IR detectors, shape-memory polymers for flexible actuators, and composite hydrogels for environmental pollutant detection. Additionally, this review addresses ongoing challenges in scalability and integration, providing insights into current research efforts aimed at overcoming these obstacles. The potential for multi-modal sensing, self-powered devices, and AI integration is discussed, suggesting a transformative impact of these composite sensors on various sectors, including health, environmental monitoring, and technology. This review demonstrates how the fusion of graphene and liquid crystals is pushing the boundaries of sensor technology, offering more sensitive, adaptable, and innovative solutions to global challenges. [ABSTRACT FROM AUTHOR]

This work aims to determine how the nematic twist-bend phase (NTB) of bismesogens containing two rigid parts of cyanobiphenyls connected with a linking chain containing n = 7, 9, and 11 methylene groups behaves in mixtures with structurally similar cyanobiphenyls nCB, n = 4–12, 14. The whole phase diagrams are presented for the CB7CB-nCB system. For the other systems, CB9CB-nCB and CB11CB-nCB, only curves corresponding to NTB-N phase transition are presented. Based on the temperature-concentration range of the existence of NTB phase, it was established that an increase in the alkyl chain length of CBnCB causes an increase in the stability of the NTB phase. But surprisingly, an increase in the alkyl chain length of nCB compounds does not change the slope of the NTB-N equilibrium line on phase diagrams. It is slightly bigger when the nCB compound has the same length of alkyl chain as the length of the linking group of a bismesogen. XRD studies were carried out for two mixtures. [ABSTRACT FROM AUTHOR]

Polymer-stabilized cholesteric liquid crystals (PSCLCs) have emerged as promising candidates for one-dimensional photonic lattices that enable precise tuning of the photonic band gap (PBG). This work systematically investigates the effect of polymer concentrations on the AC electric field-induced tuning of the PBG in PSCLCs, in so doing it explores a range of concentrations and provides new insights into how polymer concentration affects both the stabilization of cholesteric textures and the electro-optic response. We demonstrate that low polymer concentrations (≈3 wt. %) cause a blue shift in the short wavelength band edge, while high concentrations (≈10 wt. %) lead to a contraction and deterioration of the reflection band. Polarization optical microscopy was conducted to confirm the phase transition induced by the application of an electric field. The observations confirm that increased polymer concentration stabilizes the cholesteric texture. Particularly, the highly desired fingerprint texture was stabilized in a sample with 10 wt. % of the polymer, whereas it was unstable for lower polymer concentrations. Additionally, higher polymer concentrations also improved the dissymmetry factor and stability of the lasing emission, with the dissymmetry factor reaching the value of around 2 for samples with 10 wt. % of polymer additive. Our results provide valuable comprehension into the design of advanced PSCLC structures with tunable optical properties, enhancing device performance and paving the way for innovative photonic applications. [ABSTRACT FROM AUTHOR]

Heat management and color appearance are the key issues for the application of smart windows. Herein, a vibrant colored energy-saving polymer-dispersed liquid crystal (PDLC) film has been designed by combining dye-doping and the application of a heat shielding electrode. The LC droplet size could be varied by tuning the content of the dye. PDLC films featuring a low Disperse Orange 25 Azo dye concentration (0.06%) achieving an impressive contrast ratio of up to 101.5 with the transmittance reaching 79.17% at on state. Furthermore, indium tin oxide (ITO) and aluminum-doped zinc oxide (AZO) were chosen as the conductive layer materials, and the heat shielding properties of ITO and AZO/Ag/ITO (AAI) films were applied to PDLC devices and comparatively investigated. The AAI-based devices exhibited temperature reductions of 2 °C and 4 °C compared to the ITO-based devices at off and on states, respectively. This highlights the remarkable heat shielding performance and energy-saving capability of AAI-PDLC devices, as well as good flexibility and cycle stability. These AAI-based colored PDLC films exhibit substantial potential for smart window applications especially in buildings and automotive industry. [ABSTRACT FROM AUTHOR]

We report on a set of experiments directed to a problem of microparticles interaction with a disclination in a nematic liquid crystal matrix. The idea of the study consists in the visualization of the disclination by filling it with particles efficiently scattering light. A θ-cell possessing a topological defect of undetermined twist which can capture micro-sized objects was exploited. The results obtained for samples of different shape can be used as for the understanding of the nature of self-assembling clusters, as for the practical goal of increasing the visibility of a disclination being a dynamic object sensitive to temperature and other external factors and able to move the trapped particles. [ABSTRACT FROM AUTHOR]

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Polymer‐dispersed liquid crystals (PDLCs) with nano‐phase‐separated structures, in which nanometer‐sized liquid crystal (LC) domains are dispersed within a polymer matrix (nano‐PDLCs), are transparent solid materials whose optical properties can be modulated by applying an electric field (E‐field). Because the proportion of LC that can respond to an electric field is small, the specific surface area of the phase‐separated interface of nano‐PDLCs is larger than that of conventional PDLCs, resulting in higher drive voltages than those of conventional PDLCs. To lower the driving voltage of nano‐PDLCs, highly polar LCs (C3DIO) are used with a large dielectric anisotropy (>10000), and prepared nano‐PDLCs using DIO mixtures obtained by mixing them with related compounds as the host LC. Nano‐PDLCs employing DIO mixtures exhibit higher E‐field responsivity than those using conventional LC. In addition, the electro‐optical Kerr coefficient at visible wavelength is significantly high, reaching 10−8 m V−2. Furthermore, nano‐PDLCs using the DIO mixture exhibit a memory effect in which the induced birefringence remains even after the removal of the in‐plane E‐field. Memorized birefringence can be erased by heating or applying an E‐field perpendicular to the substrate surface. Nano‐PDLCs using a DIO mixture can be rewritable electro‐birefringence‐responsive materials that can memorize arbitrary birefringence values. [ABSTRACT FROM AUTHOR]

Polymer‐network liquid crystal (PNLC) possesses both advantages of low‐molecular‐weight liquid crystal (LMWLC) and liquid crystal (LC) polymer. Herein, a two‐stage polymerization strategy for the formation of unique PNLC with oxygen‐sensing properties is reported. The reaction mixture consists of 6% diacrylate RM257, 93.5% LMWLC 4‐cyano‐4′‐pentylbiphenyl (5CB), and 0.5% photoinitiator dimethoxy‐2‐phenylacetophenone (DMPA). In the first stage, the mixture is exposed to UV light for 2 min to form a primary polymer network, which is highly uniform with a planar orientation. However, some free radicals are trapped inside the LC due to the short UV exposure time. Subsequently, the trapped free radicals are released by heating the PNLC sample into an isotropic state. Under this condition, the free radicals can move freely and react with surrounding monomers to form a secondary polymer network, which is highly disordered and scatters light strongly. Because oxygen can deactivate free radicals trapped inside the PNLC, the phenomenon to detect oxygen and monitor the diffusion of oxygen through the PNLC is exploited. The PNLC‐based oxygen sensor is potentially useful for the detection of oxygen and monitoring the exposure time to oxygen. [ABSTRACT FROM AUTHOR]

With advances in terahertz technology, achieving high and nearly constant birefringence over a wide frequency range plays an extreme role in many advanced applications. In the past decade, significant research efforts have been devoted to creating new systems or elements with high birefringence. To our knowledge, the maximum birefringence attainable using artificial crystals, intrinsic liquid crystals or fiber-based systems has been less than unity. More importantly, the birefringence created in previous studies has exhibited a strong frequency dependence, limiting their practical applications. In this work, we propose a novel approach to achieve extraordinarily high birefringence over a broad terahertz frequency band (>100 GHz). To address the limitation of frequency dependence, we combined the principle of metamaterials with the form birefringence concept. First, we designed a metamaterial with an exceptionally high refractive index, thoroughly characterizing it using simulations and analytical analysis. Next, we systematically investigated the form birefringence concept, exploring its frequency response, geometric limitations, and complex refractive index differences between constituent elements. Finally, we designed a hybrid material system, combining the strengths of both metamaterials and form birefringence. Our results demonstrate the feasibility of achieving a birefringent medium exceeding three orders of magnitude higher than previous reports while maintaining a time-invariant frequency response in the sub-terahertz regime. [ABSTRACT FROM AUTHOR]

This paper discusses wave propagation in unbounded particle-based materials described by a second-gradient continuum model, recently introduced by the authors, to provide an identification technique. The term particle-based materials denotes materials modeled as assemblies of particles, disregarding typical granular material properties such as contact topology, granulometry, grain sizes, and shapes. This work introduces a center-symmetric second-gradient continuum resulting from pairwise interactions. The corresponding Euler-Lagrange equations (equilibrium equations) are derived using the least action principle. This approach unveils non-classical interactions within subdomains. A novel, symmetric, and positive-definite acoustic tensor is constructed, allowing for an exploration of wave propagation through perturbation techniques. The properties of this acoustic tensor enable the extension of an identification procedure from Cauchy (classical) elasticity to the proposed second-gradient continuum model. Potential applications concern polymers, composite materials, and liquid crystals. [ABSTRACT FROM AUTHOR]

A hyperelasticity modelling approach is employed for capturing various and complex mechanical behaviours exhibited by macroscopically isotropic polydomain liquid crystal elastomers (LCEs). These include the highly non-linear behaviour of nematic-genesis polydomain LCEs, and the soft elasticity plateau in isotropic-genesis polydomain LCEs, under finite multimodal deformations (uniaxial and pure shear) using in-house synthesised acrylate-based LCE samples. Examples of application to capturing continuous softening (i.e., in the primary loading path), discontinuous softening (i.e., in the unloading path) and auxetic behaviours are also demonstrated on using extant datasets. It is shown that our comparatively simple model, which breaks away from the neo-classical theory of liquid crystal elastomers, captures the foregoing behaviours favourably, simply as states of hyperelasticity. Improved modelling results obtained by our approach compared with the existing models are also discussed. Given the success of the considered model in application to these datasets and deformations, the simplicity of its functional form (and thereby its implementation), and comparatively low(er) number of parameters, the presented isotropic hyperelastic strain energy function here is suggested for: (i) modelling the general mechanical behaviour of LCEs, (ii) the backbone in the neo-classical theory, and/or (iii) the basic hyperelastic model in other frameworks where the incorporation of the director, anisotropy, viscoelasticity, temperature, softening etc parameters may be required. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We study the effective geometric motions of an anisotropic Ginzburg–Landau equation with a small parameter ε > 0 which characterizes the width of the transition layer. For well-prepared initial datum, we show that as ε tends to zero the solutions will develop a sharp interface limit which evolves under mean curvature flow. The bulk limits of the solutions correspond to a vector field u (x , t) which is of unit length on one side of the interface, and is zero on the other side. The proof combines the modulated energy method and weak convergence methods. In particular, by a (boundary) blow-up argument we show that u must be tangent to the sharp interface. Moreover, it solves a geometric evolution equation for the Oseen–Frank model in liquid crystals. [ABSTRACT FROM AUTHOR]

The microstructure of bone consists of nano-hydroxyapatite (nano-HA) crystals aligned within the interspaces of collagen fibrils. To emulate this unique microstructure of bone, this work applied two biomimetic techniques to obtain bone-like microstructures in vitro, that is, combining the construction of collagen liquid crystal hydrogel (CLCH) with the application of a polymer-induced liquid precursor (PILP) mineralization process. Upon the elevation of pH, the collagen macromolecules within the collagen liquid crystal (CLC) were activated to self-assemble into CLCH, whose fibrils packed into a long and dense fiber bundle in high orientation, emulating the dense-packed matrix of bone. We demonstrated that the fibrillar mineralization of CLCH, leading to a bone-like nanostructured inorganic material part, can be achieved using the PILP crystallization process to pre-mineralize the dense collagen substrates of CLCH with CaCO3, immediately followed by the in situ mineral phase transformation of CaCO3 into weak-crystalline nano-HA. The combination of CLCH with the biomineralization process of PILP, together with the mineral phase transformation, achieved the in vitro simulation of the nanostructures of both the organic extracellular matrix (ECM) and inorganic ECM of bone. This design would constitute a novel idea for the design of three-dimension biomimetic bone-like material blocks for clinical needs. [ABSTRACT FROM AUTHOR]

Ferroelectric and antiferroelectric smectic liquid crystalline (LC) phases are still at the center of investigations and interests for both their fundamental properties and variety of technological applications. This review aims to report the main contributions based on different nuclear magnetic resonance (NMR) techniques to the study of chiral liquid crystalline calamitic mesogens forming smectic phases, such as the SmA, the SmC* (ferroelectric), and the SmC*A (antiferroelectric) phases. 2H NMR and 13C NMR techniques and their combination were of help in clarifying the local orientational properties (i.e., the molecular and fragments' main orientational order parameters) at the transition between the SmA and the SmC* phases, and in the particular case of de Vries liquid crystals, NMR studies gave important clues regarding the actual models describing the molecular arrangement in these two phases formed by de Vries LCs. Moreover, this review describes how the combination of 2H NMR relaxation times' analysis, 1H NMR relaxometry, and 1H NMR diffusometry was successfully applied to the study of chiral smectogens forming the SmC* and SmC*A phases, with the determination of relevant parameters describing both rotational molecular and internal motions, collective dynamics, and translational self-diffusion motions. Several cases will be reported concerning NMR investigations of chiral ferroelectric and antiferroelectric phases, underlining the great potential of combined NMR approaches to the study of supramolecular, conformational, and dynamic properties of liquid crystals. [ABSTRACT FROM AUTHOR]

We propose a novel design of an asymmetrically anchored negative liquid crystal (LC) cell capable of linearly rotating the polarization axis of broadband light, with the rotation angle controlled by voltage. Unlike conventional LC cells that require polarization filters or retarders, our LC cell can directly modulate the polarization state of light without any additional components. The LC cell exhibits high polarization rotation efficiency over a wide wavelength range (200 nm to 2000nm), superior to the existing polarization modulators. We validate our design through theoretical calculations and numerical simulations, proving that a degree of linear polarization of over 0.95 can be achieved in the UV, visible, and NIR regions. Our design can be applied in optical communications, biological imaging, and spectroscopic technologies.

Molecular dynamics simulation produces three-dimensional data on molecular structures. The classification of molecular structure is an important task. Conventionally, various order parameters are used to classify different structures of liquid and crystal. Recently, machine learning (ML) methods have been proposed based on order parameters to find optimal choices or use them as input features of neural networks. Conventional ML methods still require manual operation, such as calculating the conventional order parameters and manipulating data to impose rotational/translational invariance. Conversely, deep learning models that satisfy invariance are useful because they can automatically learn and classify three-dimensional structural features. However, in addition to the difficulty of making the learned features explainable, deep learning models require information on large structures for highly accurate classification, making it difficult to use the obtained parameters for structural analysis. In this work, we apply two types of graph neural network models, the graph convolutional network (GCN) and the tensor embedded atom network (TeaNet), to classify the structures of Lennard-Jones (LJ) systems and water systems. Both models satisfy invariance, while GCN uses only length information between nodes. TeaNet uses length and orientation information between nodes and edges, allowing it to recognize molecular geometry efficiently. TeaNet achieved a highly accurate classification with an extremely small molecular structure, i.e., when the number of input molecules is 17 for the LJ system and 9 for the water system, the accuracy is 98.9% and 99.8%, respectively. This is an advantage of our method over conventional order parameters and ML methods such as GCN, which require a large molecular structure or the information of wider area neighbors. Furthermore, we verified that TeaNet could build novel order parameters without manual operation. Because TeaNet can recognize extremely small local structures with high accuracy, all structures can be mapped to a low-dimensional parameter space that can explain structural features. TeaNet offers an alternative to conventional order parameters because of its novelty. [ABSTRACT FROM AUTHOR]

The computation of entropy in liquids and liquid crystal (LC) phases is a big challenge in statistical physics. In this work, we extend the two-phase thermodynamic model (2PT) to shape anisotropic soft repulsive spherocylinders (SRSs) and report the absolute values of entropy for different LC phases for a range of aspect ratios L/D = 2 − 5. We calculate the density of states for different LC phases and decompose it into contributions arising from translational and rotational degrees of freedom. The translational and rotational modes are further partitioned into diffusive, gas-like, and non-diffusive, solid-like components using a fluidicity factor. In the dilute limit, the entropy values obtained from the 2PT method match exactly those of an ideal rigid rotor. We find that, for a given packing fraction, the magnitude of the total entropy is roughly equal regardless of the different LC phases associated with different aspect ratios. We also compute the excess entropy (for L/D = 5) and compare those with the values obtained using the standard integration approach of MD or Monte Carlo equation of state of SRS. The values obtained using both approaches match very well. The rotational and translational fluidicity factors are further used to determine the phase boundaries of different LC phases. [ABSTRACT FROM AUTHOR]

The elastic behavior of nematics is commonly described in terms of the three so-called bulk deformation modes, i.e., splay, twist, and bend. However, the elastic free energy contains also other terms, often denoted as saddle–splay and splay–bend, which contribute, for instance, in confined systems. The role of such terms is controversial, partly because of the difficulty of their experimental determination. The saddle–splay (K24) and splay–bend (K13) elastic constants remain elusive also for theories; indeed, even the possibility of obtaining unambiguous microscopic expressions for these quantities has been questioned. Here, within the framework of Onsager theory with Parsons–Lee correction, we obtain microscopic estimates of the deformation free energy density of hard rod nematics in the presence of different director deformations. In the limit of a slowly changing director, these are directly compared with the macroscopic elastic free energy density. Within the same framework, we derive also closed microscopic expressions for all elastic coefficients of rodlike nematics. We find that the saddle–splay constant K24 is larger than both K11 and K22 over a wide range of particle lengths and densities. Moreover, the K13 contribution comes out to be crucial for the consistency of the results obtained from the analysis of the microscopic deformation free energy density calculated for variants of the splay deformation. [ABSTRACT FROM AUTHOR]

Mesogens, which are typically stiff rodlike or disklike molecules, are able to self-organize into liquid crystal (LC) phases in a certain temperature range. Such mesogens, or LC groups, can be attached to polymer chains in various configurations including within the backbone (main-chain LC polymers) or at the ends of side-chains attached to the backbone in an end-on or side-on configuration (side-chain LC polymers or SCLCPs), which can display synergistic properties arising from both their LC and polymeric character. At lower temperatures, chain conformations may be significantly altered due to the mesoscale LC ordering; thus, when heated from the LC ordered state through the LC to isotropic phase transition, the chains return from a more stretched to a more random coil conformation. This can cause macroscopic shape changes, which depend significantly on the type of LC attachment and other architectural properties of the polymer. Here, to study the structure–property relationships for SCLCPs with a range of different architectures, we develop a coarse-grained model that includes torsional potentials along with LC interactions of a Gay–Berne form. We create systems of different side-chain lengths, chain stiffnesses, and LC attachment types and track their structural properties as a function of temperature. Our modeled systems indeed form a variety of well-organized mesophase structures at low temperatures, and we predict higher LC-to-isotropic transition temperatures for the end-on side-chain systems than for analogous side-on side-chain systems. Understanding these phase transitions and their dependence on polymer architecture can be useful in designing materials with reversible and controllable deformations. [ABSTRACT FROM AUTHOR]