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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]

Laguerre–Gaussian (LG) beams with a spiral phase (optical vortex), which feature orbital angular momenta, and vector beams (VBs) with an axially symmetric spatial polarization distribution exhibit properties different from those of conventional Gaussian beam. In this article, we introduce LG beams and VBs. Next, we explain the generation of LG beams and VBs using liquid-crystal devices. Subsequently, we report the super-resolution observation of biological samples and our observation of a PNLC (Polymer network liquid crystal) network structure using a laser scanning microscope, which comprises a liquid crystal LG-VB generator. Finally, we discuss the conservation of spiral beams and their application to optical wireless communication. [ABSTRACT FROM AUTHOR]

Liquid crystals have been extensively used in various applications, such as optoelectronic devices, biomedical applications, sensors and biosensors, and packaging, among others. Liquid crystal polymers are one type of liquid crystal material, combining their intrinsic properties with polymeric flexibility for advanced applications in displays and smart materials. For instance, liquid crystal polymers can serve as drug nanocarriers, forming cubic or hexagonal mesophases, which can be tailored for controlled drug release. Further applications of liquid crystals and liquid crystal polymers include the preparation of membranes for separation processes, such as wastewater treatment. Furthermore, these materials can be used as ion-conducting membranes for fuel cells or lithium batteries due to their broad types of mesophases. This review aims to provide an overall explanation and classification of liquid crystals and liquid crystal polymers. Furthermore, the great potential of these materials relies on their broad range of applications, which are determined by their unique properties. Moreover, this study provides the latest advances in liquid crystal polymer-based membranes and their applications, focusing especially on fuel cells. Moreover, future directions in the applications of various liquid crystals are highlighted. [ABSTRACT FROM AUTHOR]

Manipulable lenses with tunable focal length have garnered great attention due to their unique advantages including strong adjustability, low power consumption, fast response times, and ease of integration. However, in the context of advancing intellectualization, weight reduction, and miniaturization of imaging systems, mere focal length adjustment is no longer sufficient. Herein, an innovative method is introduced for creating a dynamic light manipulable (DLM) lens with surface reshaping. This breakthrough is accomplished through the collaborative integration of a medium lens with an actuator based on photo‐active liquid crystal polymer (LCP) film, where the deformation of the photo‐active LCP film can be arbitrarily controlled by meticulously designing the orientation distributions of liquid crystal (LC) mesogens within the film. The lens with three distinct surfaces, including quasi‐cone, paraboloid, and 3 × 3 paraboloid array, are demonstrated with infrared stability, robust fatigue resistance, long natural recovery time, outstanding thermal stability, and excellent solvent resistance, further confirming the feasibility of the lens application in tunable display, imaging, infrared optics, and other systems. This work holds the promise of paving the way for a new generation of imaging systems. [ABSTRACT FROM AUTHOR]

Liquid crystal polymers (LCPs) should be widely used as substrates in flexible copper clad laminate (FCCL) owing to their unique advantages. However, the poor adhesion of LCPs to copper foils hinders their applications. Considering the good adhesion between polyimides and copper foils, imide groups have previously been introduced into the main chains of LCP molecules. In the present paper, to further enhance the adhesion of the LCPEIs, the 1‐hydroxy‐7‐azabenzotriazole (HOAt) is used to terminate the main chains of LCPEI molecules, which arises from the excellent coordination interaction between the azabenzotriazole groups and copper ions. Thus, the liquid crystal poly(ester imide) (t‐LCPEI), carboxyl‐terminated liquid crystal poly(ester imide) (c‐LCPEI), and azabenzotriazole‐terminated liquid crystal poly(ester imide) (a‐LCPEI) were synthesized. The results showed that LCPEIs possessed liquid crystallinity, and the peel strength of a‐LCPEI film to copper foils was increased by about 140% and nearly 43%, respectively, compared to that of LCP and t‐LCPEI. Moreover, a‐LCPEI showed higher glass transition temperature (Tg = 211°C) than conventional LCP resins (Tg = 155°C, Vectra A), and excellent thermal properties. Meanwhile, the dielectric constant and loss of a‐LCPEI were as low as 3.04 and 9.7 × 10−3 at 10 GHz, respectively. These findings indicate that the azabenzotriazole‐terminated LCPEI is suitable to be used as the substrate material for high‐performance FCCL, and the work provides a feasible approach to enhance the adhesion and maintain the other outstanding properties of LCP. [ABSTRACT FROM AUTHOR]

Self‐assembly of chromophoric systems is a prerequisite to create well‐ordered, processable nanomaterials with multiple functionalities. In the past two decades, the field of functional organic materials has primarily focused on systems featuring only one type of dye/π‐conjugated unit. Consequently, many reports with mechanistic insights on the self‐assembly of the dyes featuring different molecular packing have been reported. Subsequently, we have witnessed several attempts to organize the multi‐chromophoric systems in solution and solid‐state via different approaches using self‐assembly as a tool. Incorporation of more than one dye is important in creating materials with tuneable optoelectronic properties. Consequently, self‐assembly of more than one chromophoric systems have been investigated to some extent. This review aims to discuss the self‐assembled materials derived from discrete π‐conjugated systems comprising more than one dye units connected through covalent bonding (multi‐chromophoric systems). Molecular design of various multi‐chromophoric systems leading to the formation of crystals, liquid crystals and supramolecular polymers have been correlated with corresponding properties. We envisage that classification of self‐assembled multi‐chromophoric systems, with a note on tuneable optoelectronic properties, can provide a deeper understanding on the molecular design strategies, which is important in the fabrication of functional organic materials with optimum performances. [ABSTRACT FROM AUTHOR]

A novel material‐constrained method for the design of liquid crystal optical devices – computer‐generated liquid crystal‐based holograms – and their manufacture using photo‐patterning is demonstrated. The developed topology optimization method is compared to the Gerchberg‐Saxton algorithm, and key advantages and disadvantages are outlined. The key novelties and advantages of the method are that it accounts for the natural relaxation and material properties of the liquid crystal and that it can account for different material or manufacturing constraints, such as maximum optical axis gradients. The viability of the method is applied for different binary and greyscale target images of varying complexity, target image sizes, and algorithms that account for the material properties of the liquid crystal. Finally, with the topology optimization design approach and photo‐patterning, it is possible to produce high‐accuracy and high‐contrast liquid crystal‐based computer‐generated holograms. [ABSTRACT FROM AUTHOR]

With the development of radio technology, 5G electronic equipment has higher requirements for materials. This has become an imperative matter to realize the controllable preparation of Thermotropic liquid crystal polyester (TLCP) foams with homogeneous microcellular. Accordingly, the foaming behavior of TLCP in isotropic state is investigated. TLCP foams are prepared by a one‐step rapid depressurization foaming method at different temperature pressures, with cell diameter in the range of 67.5–283.9 μm and the material density in the range of 0.37–0.25 g/cm3. In order to broaden the distribution of cell diameter and the density of TLCP foams, the mixture foaming agent of N2 and CO2 is used in foaming process. When mixture foaming agents are used, the cell diameter is widened to the range of 40.5–283.9 μm, and the material density is widened to the range of 0.70–0.25 g/cm3, which realizes the controllable preparation of cell diameter and material density of TLCP. The dielectric constant and dielectric loss of TLCP foams can be as low as 1.35‰ and 0.85‰ at 10 GHz, respectively. The structural regulation of low‐dielectric TLCP microcellular materials is achieved for the first time by way of varying the temperature, pressure, and co‐blowing agent ratio. [ABSTRACT FROM AUTHOR]

Liquid crystals are widely used in photonics because of their profound electro–optic properties. However, the slow switching speeds (milliseconds) and the fluid nature of liquid crystals restrict their potential use in integrated photonics. In this work, polymer‐stabilized liquid crystals are utilized as the functional material to improve the response time with a polymer network that helps pre‐orientate the liquid crystal. Additionally, plasmonic slot structures are simultaneously employed to minimize the switch voltage by confining the optical field within the electrode spacing at subwavelength scales. Thanks to the large overlap of the optical and electric fields, the scattering states of the polymer‐stabilized liquid crystal can be effectively manipulated to modulate the loss of the propagating wave, resulting in strong optical attenuation in the integrated photonic platform. Specifically, a plasmonic enhanced polymer‐stabilized liquid crystal photonic device for operation at 1550 nm, which has a length of only 10 µm and shows an extinction ratio of 0.38 dB µm−1, with a power consumption of less than 6 µW and a response time ≈20 µs, resulting in a figure‐of‐merit of 0.012 mW. [ABSTRACT FROM AUTHOR]

Photoisomerizable molecules in liquid crystals (LCs) allow for photoinduced phase transitions, facilitating applications in a wide variety of photoresponsive materials. In contrast to the widely investigated azobenzene structure, research on the photoinduced phase-transition behavior of imine-based LCs is considerably limited. We herein report the thermal and photoinduced phase-transition behaviors of photoisomerizable imine-based LC dimers with twist–bend nematic (NTB) phases. We synthesize two homologous series of ester- and thioether-linked N-(4-cyanobenzylidene)aniline-based bent-shaped LC dimers with an even number of carbon atoms (n = 2, 4, 6, 8, and 10) in the central alkylene spacers, namely, CBCOOnSBA(CN) and CBOCOnSBA(CN), possessing oppositely directed ester linkages, C=OO and OC=O, respectively. Their thermal phase-transition behavior is examined using polarizing optical microscopy and differential scanning calorimetry. All dimers form a monotropic NTB phase below the temperature of the conventional nematic (N) phase upon cooling. Remarkably, the NTB phases of CBCOOnSBA(CN) (n = 2, 4, 6, and 8) and CBOCOnSBA(CN) (n = 6 and 8) supercool to room temperature and vitrify without crystallization. In addition, the phase-transition temperatures and entropy changes of CBCOOnSBA(CN) are lower than those of CBOCOnSBA(CN) at the same n. Under UV light irradiation, the NTB and N phases transition to the N and isotropic phases, respectively, and reversibly return to their initial LC phases when the UV light is turned off. [ABSTRACT FROM AUTHOR]

This study focuses on the development and characterization of molecularly imprinted thin films in the absence and presence of a liquid crystal monomer, as well as the evaluation of these materials for recognition of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Molecular imprinted polymers (MIPs) and non-imprinted polymers (NIPs) were prepared by using two functional monomers, n-butylmethacrylate (BMA) and liquid crystalline (LC) 6-(4-cyanophenyl-4′phenoxy) hexyl acrylate (A6OCB). The resulting (MIPs) and (NIPs) materials were characterized by infrared spectroscopy (FTIR), Raman spectroscopy, polarized optical microscopy (POM), and atomic force microscopy (AFM). The entire monomer consumption, as well as the successful loading and extraction of the 2,4-D molecules, were validated by FTIR and Raman analyses. POM and AFM characterization revealed that the percentage of liquid crystal influenced the distribution of the liquid crystal domains and that the MIP films exhibited remarkable porosity. The experimental results revealed that the MIP films had a substantially higher adsorption capacity toward 2,4-D than the NIP materials and that increasing the liquid crystal content increased the adsorption capacity of both the MIP and NIP films. The selectivity tests in the presence of phenoxyacetic acid (POAc) showed that the MIP films exhibited higher affinity for 2,4-D than for the POAc. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers are rubber-like solids with liquid crystalline mesogens (stiff, rod-like molecules) incorporated either into the main chain or as a side chain of the polymer. These solids display a range of unusual thermo-mechanical properties as a result of the coupling between the entropic elasticity of rubber and the orientational phase transitions of liquid crystals. One of these intriguing properties is the soft behavior, where it is able to undergo significant deformations with almost no stress. While the phenomenon is well-known, it has largely been examined in the context of homogenous deformations. This paper investigates soft behavior in complex inhomogeneous deformations. We model these materials as hyperelastic, isotropic, incompressible solids and exploit the seminal work of Ericksen, who established the existence of non-trivial universal deformations, those that satisfy the equations of equilibrium in every hyperelastic, isotropic, incompressible solid. We study the inflation of spherical and cylindrical balloons, cavitation and bending. [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]

As the number of wirelessly connected devices continues to grow, dealing with the huge volume of data traffic has become a major challenge. This has led to a greater emphasis on sub-6 GHz applications in 5G, as faster speeds and more extensive services are increasingly necessary to support a wide range of emerging applications. These applications require wireless devices with compact dimensions and highly flexible mechanical properties that can adapt to their environmental needs. To achieve this, flexible polymers offer numerous advantages, including lightweight, low cost, easy processability, and the ability to conform to complex and irregular surfaces, making them ideal for use in wearable devices and other flexible electronics applications. This work provides a thorough analysis of a dual-band microstrip patch antenna, measuring 18 × 27 × 0.3 mm3 for polyimide polymer (PI) and 19.5 × 29.5 × 0.3 mm3 for liquid crystal polymer (LCP). The obtained results obviously depict that the antenna performs better in terms of reflection coefficient (S11) and the realized gain (dBi) at the (2.34–2.56 GHz) and (4.45–5.78 GHz) frequency bands when the substrate is approximately 0.3 mm thick. The antenna also maintains its performance during bending tests. Furthermore, the LCP polymer provides a higher gain of about 3.51 dBi as compared to the polyimide polymer (PI). The results suggest that the proposed antenna is suitable for a wide range of wireless 5G communication devices operating in the sub-6 GHz band. [ABSTRACT FROM AUTHOR]

The presence of a polymer network and/or the addition of ferroelectric nanoparticles to a nematic liquid crystal are found to lower transition temperatures and birefringence, which indicates reduced orientational order. In addition, the electro-optic switching voltage is considerably increased when a polymer network is formed by in situ polymerization in the nematic state. However, the resulting polymer network liquid crystal switches at similar voltages as the neat liquid crystal when polymerization is performed at an elevated temperature in the isotropic state. When nanoparticle dispersions are polymerized at an applied DC voltage, the transition temperatures and switching voltages are reduced, yet they are larger than those observed for polymer network liquid crystals without nanoparticles polymerized in the isotropic phase. [ABSTRACT FROM AUTHOR]

Supramolecular liquid crystals (SLCs) are attractive materials for fabricating devices with new optoelectronic functions. Conventional SLCs are made from hydrogen‐bonded mesogens. However, these mesogens suffer from high melting points, and the types of formable aggregates are limited owing to the directionality of the hydrogen bonding. Therefore, to fabricate non‐hydrogen‐bonded SLCs, we hypothesized that the introduction of tertiary amide groups into calamitic molecules would be advantageous because they have an L‐shaped structure with N‐ or C‐alkyl side chains not aligned along the long axis and the flexibility to undergo cis–trans isomerization. In this study, we developed a novel non‐hydrogen‐bonded SLC by assembling an L‐shaped dimer composed of calamitic molecules (phenyltolanes) with tertiary amides at their ends. These molecules exhibited a smectic B phase. The phase transition temperature of the SLCs from crystal to liquid crystal phase was low despite the long π‐conjugated core. Wide‐angle X‐ray diffraction and variable‐temperature Fourier‐transform infrared measurements revealed dimer formation by weak intermolecular interactions, that is, the molecular recognition of L‐shaped molecules, and mobility of the alkyl groups attached to amide driven by cis–trans isomerization in the liquid crystal phase. Thus, cis–trans isomerization of tertiary amides contributed enormously to the formation and lower clearing points of this SLC. The developed method can be used not only to develop non‐hydrogen‐bonded SLCs but also to develop novel soft matter with controlled properties by incorporating the SLCs, as the aggregates can be controlled to impart desired functionalities. [ABSTRACT FROM AUTHOR]

The production of polymer‐stabilized vertically aligned (PSVA) displays requires two UV processes for liquid crystal (LC) alignments. UV1 is usually short for pre‐tilt angle formation, while UV2 takes approximately 90 minutes to consume the remaining reactive monomers (RMs). Therefore, shortening the UV2 process can significantly reduce the power consumption and maintenance costs of UV lamps during LCD fabrication. Herein, we report a novel LC material consisting of fast‐reaction RMs. With the addition of fast‐reaction RMs, the UV2 process can be dramatically decreased from 90 min to 20 min. Furthermore, the reduction of the UV2 process shows competitive optical properties, reliabilities and pre‐tilt angle stabilities compared with the reference. Overall, new fast‐reaction LC materials are beneficial to energy saving and the cost competitiveness of the company. [ABSTRACT FROM AUTHOR]

We have developed a reflective polarization volume grating using liquid crystal polymer for SWIR with high efficiency and a large diffraction angle. By using this grating and a lightguide system, we demonstrated a sensor system that can capture identical images simultaneously in both visible and SWIR light. [ABSTRACT FROM AUTHOR]

Photoalignment by azo dye nanolayers can provide high alignment quality for large-area liquid crystal devices. Application of this technology to active optical elements for signal processing and communications is a hot topic of photonics research. In this article, we review recent demonstrations and performance of liquid crystal photonic devices, discuss the advantages of the proposed technology, and identify challenges and future prospects in the research field of photoaligned multi-domain liquid crystal structures. We believe that the developments discussed here can provide directions for future research and potential opportunities for applications of liquid crystal devices based on multi-domain photoalignment. [ABSTRACT FROM AUTHOR]

Chiral self‐assembly has often been found to be an efficient strategy for the development of high‐performance circularly polarized luminescent (CPL) materials, through the regulation of the ordered helical superstructure blocks in liquid crystal media. Here, the design and synthesis of two pairs of axially chiral emitters (BBXT‐3‐Br and BOHXT‐3‐Br) are reported based on bromoxanthone. And the chiral self‐assembled liquid crystal polymer (LCP) framework (PRM257) is demonstrated by mixing of the emitters with liquid crystal monomer (RM257) through thermal annealing and photoinitiated polymerization. Both BBXT‐3‐Br@PRM257 and BOHXT‐3‐Br@PRM257 exhibited excellent room temperature phosphorescence (RTP) properties. In addition, BBXT‐3‐Br@PRM257 enantiomers showed afterglow with an average lifetime (τ) of 162.41 ms and emitted blue CPL (λem = 450 nm, ΦFL = 1.3%, |gFL| = 0.071), although weak circularly polarized RTP (CP‐RTP) is observed. Interestingly, BOHXT‐3‐Br@PRM257 with a less conjugated system emits red RTP (τ = 98.83 ms) and also intense CP‐RTP (λem = 612 nm, ΦPhos = 0.45%, |gRTP| = 0.057). [ABSTRACT FROM AUTHOR]

Due to the ability to switch between transparent and light scattering states, polymer dispersed liquid crystals (PDLC) and polymer stabilised cholesteric liquid crystals (PSCLC) are widely used in smart windows and flexible displays. A novel double-layer optical switch fabricated from a PDLC-PVA-PSCLC structure has been developed in this study, and the optimal formulation of each layer of the structure was investigated. In addition, the effect of adding (spin-coating) nanoparticles on overall switch performance was investigated. The double-layer switch under optimal conditions achieved 89.1% UV shielding, which also possessed excellent layer-by-layer driving performance and was able to modulate the UV shielding rate according to the voltage, with a tunable range of 74.83%-94.33%. Consequently, this optical device holds great promise for significant improvement and application in smart windows and flexible displays. [ABSTRACT FROM AUTHOR]

Lipophilic biphenylthiophene‐ and phenanthrothiophene‐triazine compounds, BPTTn and CPTTn, respectively, were prepared by a tandem procedure involving successive Suzuki‐Miyaura coupling and Scholl cyclodehydrogenation reactions. These compounds display photoluminescence in solution and in thin film state, solvatochromism with increasing solvent's polarity, as well as acidochromism and metal ion recognition stimuli‐responsive fluorescence. Protonation of BPTT10 and CPTT10 by trifluoroacetic acid results in fluorescence quenching, which is reversibly restored once treated with triethylamine (ON‐OFF switch). DFT computational studies show that intramolecular charge transfer (ICT) phenomena occurs for both molecules, and reveal that protonation enhances the electron‐withdrawing ability of the triazine core and reduces the band gap. This acidochromic behavior was applied to a prototype fluorescent anti‐counterfeiting device. They also specifically recognize Fe3+ through coordination, and the recognition mechanism is closely related to the photoinduced electron transfer between Fe3+ and BPTT10/CPTT10. CPTTn self‐assemble into columnar rectangular (Colrec) mesophase, which can be modulated by oleic acid via the formation of a hydrogen‐bonded supramolecular liquid crystal hexagonal Colhex mesophase. Finally, CPTTn also form organic gels in alkanes at low critical gel concentration (3.0 mg/mL). Therefore, these star‐shaped triazine molecules possess many interesting features and thus hold great promises for information processing, liquid crystal semiconductors and organogelators. [ABSTRACT FROM AUTHOR]

A nonterminal liquid crystal epoxy monomer is used to create an epoxy–amine network with a typical diamine 4,4′diaminodiphenylmethane. The plain matrix is compared to matrices modified with inorganic fillers: TiO2 or SiO2. Conditions of the curing reaction and glass transition temperatures in the cured products are determined through differential scanning calorimetry and broadband dielectric spectroscopy. The curing process is also followed through optical and electrical observations. The dielectric response of all investigated networks reveals a segmental α-process related to structural reorientation (connected to the glass transition). In all products, a similar process associated with molecular motions of polar groups also appears. The matrix modified with TiO2 exhibits two secondary relaxation processes (β and γ). Similar processes were observed in the pure monomer. An advantage of the network with the TiO2 filler is a shorter time or lower temperature required for optimal curing conditions. The physical properties of cured matrices depend on the presence of a nematic phase in the monomer and nonterminal functional groups in the aliphatic chains. In effect, such cured matrices can have more flexibility and internal order than classical resins. Additional modifiers used in this work shift the glass transition above room temperature and influence the fragility index in both cases. [ABSTRACT FROM AUTHOR]

Four binary mixtures are isolated from the hydrogen bond liquid crystalline mesogenic complexes comprising methyl malonic acid (MM) and p-n heptyloxy benzoic acid (7BAO) abbreviated as MM + 7BAO & p-n dodecyloxy (12BAO) benzoic acid abbreviated as MM + 12BAO as the precursors exhibit rich phase polymorphism. Variation in the even set of molar proportion in steps of 0.2 leads to the formation of four binary mixtures. Each of the precursors used for the preparation of binary mixtures are treated as X and Y component whose molar ratio varies accordingly. Spectroscopic analysis of the binaries confirms the hydrogen bond existence between the binary mixtures. Phase variance and their textural observations are made through polarizing optical microscopic studies. Thermal properties possessed by these binary mixtures such as phase transition temperatures, enthalpy values, thermal equilibrium, thermal stability, order of phase transition and specific heat capacity are extensively investigated from the differential scanning thermograms obtained for the binaries prepared. These calorimetric investigations suggest the mesophases of the binaries for apt display, thermal and optical applications. [ABSTRACT FROM AUTHOR]

Achieving adaptive behavior in artificial systems, analogous to living organisms, has been a long-standing goal in electronics and materials science. Efforts to integrate adaptive capabilities into synthetic electronics traditionally involved a typical architecture comprising of sensors, an external controller, and actuators constructed from multiple materials. However, challenges arise when attempting to unite these three components into a single entity capable of independently coping with dynamic environments. Here, we unveil an adaptive electronic unit based on a liquid crystal polymer that seamlessly incorporates sensing, signal processing, and actuating functionalities. The polymer forms a film that undergoes anisotropic deformations when exposed to a minor heat pulse generated by human touch. We integrate this property into an electric circuit to facilitate switching. We showcase the concept by creating an interactive system that features distributed information processing including feedback loops and enabling cascading signal transmission across multiple adaptive units. This system responds progressively, in a multi-layered cascade to a dynamic change in its environment. The incorporation of adaptive capabilities into a single piece of responsive material holds immense potential for expediting progress in next-generation flexible electronics, soft robotics, and swarm intelligence. There is significant interest in developing electronic units that can perform sensing, signal processing, and actuation functions independently, similar to biological systems. Lyu et al. develop electronic units based on liquid crystal oligomer networks that exhibit adaptive behavior in response to environmental stimuli such as light and heat. [ABSTRACT FROM AUTHOR]

In this study cinnamaldehyde (CA) doped polyurethane cholesteryl pelargonate cholesteric liquid crystal composite membranes were produced and their properties were examined for use in biological applications. The relationship between the blood coagulation and protein adsorption was studied and the results showed that increasing CA concentration allowed an improvement in biological properties of them. Additionally, the effect of CA on the hyrophobicity of these membranes was investigated by determining water holding capacity, contact angles. The mechanical strength of these membranes were determined and it was found that their strength increased and the ability to elongate decreased with an increasing CA dopant concentration. [ABSTRACT FROM AUTHOR]

We propose a novel mechanism for visualizing the chirality of compounds in solution using a vertical contact‐separation process (VCSP) of liquid crystal micro‐droplets (LCμDs). By employing the VCSP between target micro‐droplets and sensor LCμDs, the chiral compounds initially introduced in the target micro‐droplets diffuse into coalescent micro‐droplets. After the VCSP, we observed a wavelength shift in the selective reflection from the sensor LCμDs, allowing us to visualize the chirality present in the target micro‐droplets. To quantitatively analyze the wavelength shift of the selective reflection, we utilized reflective spectroscopic techniques. Our findings demonstrate that the chirality sensing mechanism achieves a detection accuracy of 10 μg. Moreover, this chiral sensing mechanism can be effectively applied to two‐dimensional micro‐droplet array systems. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The polarization‐independent liquid crystal (LC) phase modulators can greatly improve the efficiency and reduce the complexity of the optical system. However, it is difficult for the LC phase modulator to achieve both good low‐loss modulation and polarization‐independent properties. A LC phase modulator of single layer microdomain twisted structure has been proposed to achieve good polarization independence and low loss in phase modulation. However, the multi‐exposure in fabrication is difficult to realize in production process. To simplify the fabrication process, an alternate LC (ALC) mask is proposed with the alternate arrangement of twist‐nematic (TN) LC and nematic LC. The fabrication process is optimized to two steps exposure with the usage of ALC and is suitable for large‐amount‐production. The measurement results showed that the single layer microdomain twisted LC phase modulator may get very low polarization dependence, about 3.52% under 2π phase modulation depth, with low loss. The device shows good potential application in optical communication, wearable device, and display. [ABSTRACT FROM AUTHOR]

The electrically‐directed, isothermal response of liquid crystal elastomers (LCEs) to an applied electric field is a compelling approach to realize spatially tailorable, sequence‐controllable, and high‐frequency deformation. The electromechanical response is facilitated by coating aligned LCEs with compliant electrodes. Upon application of an electric field, the electrodes attract and generate Maxwell stress. The directional difference in moduli for aligned LCEs produces directional deformation of the material and does not require mechanical bias or framing. Here, LCEs prepared from a newly reported thiol‐ene reaction are explored as DEAs with improved mechanical and dielectric properties. This report details that incorporating a difunctional liquid crystalline monomer composed of allyl ether functional groups reduces Young's modulus, increases the dielectric constant, and improves cyclic recovery compared to an analogous LCE prepared by thiol‐ene polymerization. Electrically‐induced, isothermal deformation of as much as 30% strain is reported. The facile chemistry and enhanced electromechanical response reported here may enable the functional integration of LCEs in applications such as robotics. [ABSTRACT FROM AUTHOR]

The liquid crystal state (LC) in polymer chemistry is a topic discussed in varied materials research. The anisotropic properties typical of these compounds are mostly the result of the presence of mesogens in the structure of liquid crystals. This article traces the development of liquid crystal science, focusing on liquid crystal epoxy resins (LCERs) and emphasizing the crucial role of mesogens and their diverse effect on the materials. It also highlights the importance of understanding the morphology of LC polymers, explaining their profound impact on material properties and performance. It explores the cross-linking process of liquid crystal resins and composites, describing how changes in structural factors affect material structure. The article also provides information about hardeners and their influence on the cross-linked structure. Various nanofillers were also discussed, elucidating their impact on the resulting composites. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have emerged as a new class of materials, displaying a unique capability to self-assemble into micelles, liposomes, liquid crystals, and microemulsions. Despite evident interest, advancements in the controlled formation of amphiphilic ILs remain in the early stages. Taking inspiration from nature, we introduced the concept of lipid-like (or lipid-inspired) ILs more than a decade ago, aiming to create very low-melting, highly lipophilic ILs that are potentially bio-innocuous – a combination of attributes that is frequently antithetical but highly desirable from several application-specific standpoints. Lipid-like ILs are a subclass of functional organic liquid salts that include a range of lipidic side chains such as saturated, unsaturated, linear, branched, and thioether while retaining melting points below room temperature. It was observed in several homologous series of [Cnmim] ILs that elongation of N-appended alkyl chains to greater than seven carbons leads to a substantial increase in melting point (Tm) – which is the most characteristic feature of ILs. Accordingly, it is challenging to develop ILs with low Tm values while preserving their hydrophobicity and self-organizing properties. We found that two alternative Tm depressive approaches are useful. One of these is the replacement of the double bonds with thioether moieties in the alkyl chains, as detailed in several published papers detailing the chemistry of these ILs. Employing thiol–ene and thiol–yne click reactions is a facile, robust, and orthogonal method to overcome the challenges associated with the synthesis of alkyl thioether-functionalized ILs. The second approach involves replacing the double bonds with the cisoid cyclopropyl motif, mimicking the strategy used by certain organisms to modulate cell membrane fluidity. This discovery has the potential to greatly impact the utilization of lipid-like ILs in various applications, including gene delivery, lubricants, heat transfer fluids, and haloalkane separations, among others. This feature article presents a concise, historical overview, highlighting key findings from our work while offering speculation about the future trajectory of this de novo class of soft organic-ion materials. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystal oligomers are an interesting class of temperature responsive structurally colored materials. However, the role of endcap molecules in these oligomers is rather unexplored. In this work, we demonstrate the role of endcap molecules on structural color stability and hypsochromic shift in temperature‐responsive cholesteric liquid crystal oligomers. First, new liquid crystal monoacrylate endcap molecules are synthesized, which are then used to synthesize various cholesteric liquid crystal oligomers. In addition, cholesteric oligomers using commercial monoacrylate endcap molecules are also prepared. It is found that the molecular weight and the polydispersity of the oligomers can be tuned by the endcapping molecules. The oligomers are used to produce reflective, structurally colored coatings. It was found that the coatings using the commercial monoacrylate lose their color and crystallize over time, most likely due to the presence of crystalline dimers. The coatings containing the newly synthesized monoacrylate endcap molecules did not exhibit this crystallization, resulting in structurally colored coatings that remained stable over time. These latter coatings possessed temperature responsive hypochromic behavior, which makes them interesting for advanced optical applications. [ABSTRACT FROM AUTHOR]

By introducing two cholesteric liquid crystal monomers with different chain lengths (M1 and M2) and brominated naphthalimide fluorescent monomer (M3) into polymethyl hydrosiloxane, a series of fluorescent cholesteric liquid crystal polymers (FL-LCP) was prepared, which not only have excellent performance of liquid crystal and fluorescence but also own performance of selective reflection. Their chemical structures were confirmed to be in accord with molecular design by FT-IR and 1 H NMR spectroscopy, and found them with excellent thermal stability, mesomorphic behaviour and thermal performance by TGA, POM, DSC and XRD, and confirmed all the polymers belonged to the cholesteric phase. The FL-CLCPs emitted different intensity fluorescence under UV light, and conclusions about the relationship between fluorescence and temperature had been drawn. A comparative study was conducted on the fluorescence properties of powders and films of monomers and polymers. [ABSTRACT FROM AUTHOR]

Polymer dispersed liquid crystal (PDLC) films and polymer-stabilised cholesteric liquid crystals (PSCLC) films have been widely applied in smart optoelectronics due to electrical switching properties. In this study, fluorescent dyes were introduced into PDLC films and combined with PSCLC films to invent a new type of optical shutter, and the optimal formulations of each of liquid crystal structural layers were investigated. Then, PDLC anti-counterfeit optical device doped with fluorescent materials were fabricated by UV curing method using polymerisation-induced phase separation. The novel optical shutter could be driven layer by layer at room temperature according to different voltages to realise the switching of three states, namely, off state, PDLC layer-driven, and full-driven (open state). Samples under optimal conditions showed that the new optical shutter could achieve 96.5% UV shielding in the off state and had a long lifetime. The results demonstrate the attractive potential of the new optical shutter for optoelectronic devices and smart curtain applications. [ABSTRACT FROM AUTHOR]

Polymer Dispersed Liquid Crystal (PDLC) films have been widely used as electronically controlled dimming technology, and solving the problem of narrow angle of PDLC is a cutting-edge challenge for their application. In this paper, a theoretical model of the viewing angle characteristics of PDLC is constructed, and the corresponding samples are experimentally fabricated. It is found that the simulation results of transmittance changing with the viewing angle are in good agreement with the experimental results. Furthermore, the technical approaches to improve PDLC viewing angle characteristics and achieve a wide viewing angle are discussed theoretically. The results show that the PDLC films for wide viewing angle can be obtained by using liquid crystal materials with smaller anisotropy of refractive index and polymer materials with refractive index slightly higher than the ordinary refractive index of liquid crystal. [ABSTRACT FROM AUTHOR]

In this study, a novel light switch was developed by integrating polymer dispersion liquid crystals (PDLC) and polymer-stabilised cholesteric liquid crystals (PSCLC), leveraging the infrared shielding properties of these two liquid crystal films. The optimal formulation for each layer of the liquid crystal structure was investigated. Subsequently, the effects of light intensity, high temperature, and humidity on the performance of the light switch were examined. This new light switch can be selectively driven layer by layer at room temperature, achieving three states: the off state, PDLC layer-driven state, and full-driven (on state). This functionality serves the purpose of electrogenerated temperature control. Samples under optimal conditions exhibited a 31% enhancement in infrared shielding compared to a single-layer PDLC film. Moreover, the IR shielding rate could be adjusted according to the voltage applied, realising an intelligent temperature-control effect. The results of this study suggest that such bilayer liquid crystal structures hold significant potential for application in electro-optical devices and smart curtain systems. [ABSTRACT FROM AUTHOR]

In this paper, two series of side chain fluorescent cholesteric liquid crystal polymers (FL-ChLCPs) were prepared by one-step method with polymethyl-hydrosiloxane (PMHS) as the main chain. Two series of polymers differ in the structure of vinyl flexible chains of fluorescent monomer, the comparative study was conducted on their performance of liquid crystal and fluorescence. The compounds and polymers were characterised using conventional methods. The results indicated all polymers possessed dual optical properties of fluorescence and selective reflection, they also had excellent thermal stability. The FL-ChLCPs emitted different intensity fluorescence under UV light, the fluorescence intensity has a certain relationship with temperature and aggregation-caused quenching effect only occurs when the content of fluorescent monomer in the polymer exceeds 20%. [ABSTRACT FROM AUTHOR]

A method for the design and fabrication of short‐focus liquid crystal Pancharatnam‐Berry lenses is demonstrated. With Electromagnetic modeling of dual‐twist lens by finite element method, the relationship between lens diffraction efficiency and f‐number is revealed. A fabrication light path of preparing small f‐number and short‐focal lenses by polarization holography is proposed, and the small f‐number microlens array is prepared experimentally. Both simulation and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

Liquid crystal polarization holograms (LCPHs) based on photo‐alignment and self‐assembled liquid crystal are attractive for the attributes like micrometer ultra‐thinness, high efficiency and dynamic tunability. Previous fabrication methods are limited in the degree‐of‐freedom (DoF) in both photoalignment process and liquid crystal deposition. This work presents an full‐DoF LCPH by freeform exposure and inkjet printing, which is exemplified by building a full‐color retinal scanning display without color crosstalk. [ABSTRACT FROM AUTHOR]

Intrinsically fluorescent liquid crystals are highly sought after for a variety of applications. Most of the measurements of photo-physical properties of liquid crystals are made in dilute solutions, which is mainly due to the relative ease of both these measurements and the interpretation of data. The fluorescence spectra depend on a number of parameters including the concentration in liquid crystal solutions, the device geometry, and the mesophase in which the spectra have been measured. Working with neat, or concentrated, liquid crystal samples adds experimental complexities such as the inner filter effect (IFE), which affects the collection of data, interpretation of the results, and accuracy of the conclusions. In this paper, we present a systematic study of the photo-physical properties of both a model reference material, Nile red, and a nematic liquid crystal, 4-cyano-4′-pentylbiphenyl (5CB). The influence on the emission spectra of an increasing solute concentration is investigated and discussed. Moreover, a detailed investigation of the influence of the used device geometry, as well as the choice of appropriate data fitting methodologies, are presented. [ABSTRACT FROM AUTHOR]

Recently, a large family of at least 14 discotic liquid crystals was discovered that are exceptions to the conventional paradigm that discotic mesogens tend to feature long, flexible tails on their periphery. To understand why these materials are liquid crystals, as well as the structural determinants of discotic phase behavior, we studied a group of closely related small tail-free disk-like molecules, including both mesogenic and non-mesogenic compounds differing only in the position of a single fluorine substituent. The rigidity and structural simplicity of these molecules make them well suited to for study by large, fully all-atom simulations. Using a combination of static and dynamic metrics, we were able to identify several key features of the columnar mesophase and, thereby, conclusively identify a columnar liquid crystalline mesophase present in a subset of our systems. Our simulations feature molecules hopping between columns in the columnar mesophase and distinctive molecular rotations in 60° steps about the columnar axis. The ability to create and characterize columnar mesophases in silico provides a potent tool for untangling the structural determinants of liquid crystalline behavior in these and other tail-free discotic liquid crystals. [ABSTRACT FROM AUTHOR]

Three naphthorosarins, antiaromatic expanded porphyrins bearing different meso substituents (NRos 1–3), designed to self-assemble into columnar liquid crystalline (LC) structures, were synthesized and characterized using polarized optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), as well as supporting computational calculations. The substituents were found to play a crucial role in modulating the LC behaviour. [ABSTRACT FROM AUTHOR]

Circularly polarized luminescent (CPL) materials have significant promising applications in organic light‐emitting diodes, asymmetric synthesis, and other fields. However, due to the instability of triplet‐state excitons, how to achieve an effective combination of CPL with room‐temperature phosphorescence (RTP) remains a formidable challenge. Here, a simple and feasible method for constructing polymer‐based CPRTP materials is proposed by preparing chiral phosphorescent liquid crystals through copolymerization. A series of RTP chiral liquid crystal copolymers are successfully synthesized by copolymerizing phosphorescent monomer bearing chiral cholesterol mesogen with phosphorescent monomer bearing dibenzofuran chromophore. Due to the introduction of chiral cholesterol mesogen, copolymers can form chiral smectic C‐phase liquid crystals. Utilizing their selective reflection characteristic, efficient CPRTP is achieved, with a glum value of up to −1.6 × 10−2. In addition, both components in copolymers exhibit RTP properties and show significant differences in phosphorescence color and lifetime. By changing the composition of copolymers, the regulation of their phosphorescence properties is successfully achieved. As a result, multicolor‐tunable and time‐dependent CPRTP materials are successfully prepared. [ABSTRACT FROM AUTHOR]

A novel homologous series of cinnamoyl ester comprising of elven (C1 to C16) homologues liquid crystal (LC) samples have been synthesized and characterized using instrumental methods (spectral and thermal) of analysis and DFT approach. As results, middle ordered melting type of series with exhibition of nematic mesophase were observed. The observed mesogenic properties and transition temperature are affected by the size of alkyl chains that shows mesomorphism is susceptible to molecular structure. The prepared LCs of cinnamoyl ester derivatives were further examined for their biological activities and the obtained results indicates a good biological potential for the studied LC materials. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystal polymer network (CLCN) films have attracted much attention for their applications as optical filters and in displays, decoration, and anti-counterfeiting. Herein, two pairs of chiral bola-type epoxy liquid crystals with a cholesteric mesophase were synthesized. Their mixtures exhibit thermochromic behaviour. CLCN films with structural colours were prepared using their mixtures through photopolymerization. The Bragg reflection band and the handedness of the CLCN film can be controlled by changing the weight ratio of the chiral liquid crystals. Patterned CLCN films were prepared based on their thermochromic behaviour, the addition of a luminescent compound, or the handedness of the liquid crystal mixture, and they were potentially applied in decoration and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Liquid crystalline nanoparticles (LC NPs) are a kind of polymer NPs with LC mesogens, which can form special anisotropic morphologies due to the influence of LC ordering. Owing to the stimuli‐responsiveness of the LC blocks, LC NPs show abundant morphology evolution behaviors in response to external regulation. LC NPs have great application potential in nano‐devices, drug delivery, special fibers and other fields. Polymerization‐induced self‐assembly (PISA) method can synthesize LC NPs at high solid content, reducing the harsh demand for reaction solvent of the LC polymers, being a better choice for large‐scale production. In this review, we introduced recent research progress of PISA‐LC NPs by dividing them into several parts according to the LC mesogen, and discussed the improvement of experimental conditions and the potential application of these polymers. [ABSTRACT FROM AUTHOR]

We found that a new stable state of porphyrin monolayer can be induced by liquid crystal molecules. We measured the surface pressure per area of the monolayer at various molar fractions of liquid crystal. The polarity and orientation of liquid crystal molecules were investigated by recording the surface potential value of the monolayer. We found that the dispersion of porphyrin in a liquid crystal solution led to changes in the surface structure and the surface pressure of the monolayer at the air–water interface. Therefore, the surface potential records can be used to control the orientation of liquid crystal and the formation of mono- or multilayers of Langmuir thin film. The plots obtained for solutions with a mole fraction of liquid crystal greater than 0.333 showed repulsive interactions between porphyrin and liquid crystal molecules. [ABSTRACT FROM AUTHOR]

Eight mesogenic liquid crystalline complexes are formed between 4-Nitrobenzaldehyde and p-n alkyloxy benzoic acids whose carbon number varies from pentyl to dodecyl. Chemical, optical and thermal investigations are carried out to all the mesogenic complexes in order to establish the intermolecular hydrogen bonding, mesophase formation, their transition temperatures, enthalpy values, order of transition, thermal equilibrium, thermal stability factor, behavior of mesophases with respect to temperature and specific heat capacity. All the investigations details the chemical, optical and thermal properties possessed by the mesogenic complexes which make them for the apt applicational viability. [ABSTRACT FROM AUTHOR]

Tunable optical lenses are in great demand in modern technologies ranging from augmented and virtual reality to sensing and detection. In this work, electrically tunable microlenses based on a polymer‐stabilized chiral ferroelectric nematic liquid crystal are described. The power of the lens can be quickly (within 5 ms) varied by ≈500 diopters by ramping an in‐plane electric field from 0 to 2.5 V µm−1. Importantly, within this relatively low‐amplitude field range, the lens is optically isotropic; thus, its focal length is independent of the polarization of incoming light. This remarkable performance combines the advantages of electrically tuned isotropic lenses and the field‐controlled shape of the lens, which are unique properties of chiral ferroelectric nematic liquid crystals and have no counterpart in other liquid crystals. The achieved lens performance represents a significant step forward as compared to liquid lenses controlled by electrowetting and opens new possibilities in various applications such as biomimetic optics, security printing, and solar energy concentration. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesised cholesteryl 4-allyloxybenzoate (MB), crosslinking agent dodecane-1,12-diyl bis(undec-10-enoate) (MG), and A'BGF series liquid crystalline elastomer (LCE) films which take polymethylhydrosiloxane (A') as the backbone, MB as the cholesteric liquid crystal (LC) monomer, and MG and bis-vinyl silicone oil (MF) with different reactivities as cross-linking agent for exploring the effect of the change of MF content on the properties of the elastomeric films. The experimental results show that the synthesised MB, MG, and the LCE films are all consistent with the molecular design; MB is an enantiotropic cholesteric LC. The synthesised LCE films are cholesteric LCs, have certain selective reflection characteristic, higher thermal stability, and their Tg decreased down to 3.9°C as MF increasing. During the heating and cooling, the liquid crystalline properties of the LCE films have a good reversibility. Among the synthesised LCE films, A'BGF-2 has stretching radio of 264.8% at room temperature, with the best elastic properties. By adjusting the ratio of MF, the content of small-molecule MB remained in the films can be changed, which will affect the optical properties and elasticity of the LCE films. The experiments provide a method for the preparation of highly elastic side chain LCE film. [ABSTRACT FROM AUTHOR]