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

A novel design and approach for the realization of liquid crystal optical waveguides using photopatterning as a manufacturing method is presented. The developed method is used to demonstrate straight waveguides of different widths and curved waveguides with different radius of curvature. The waveguides are terminated with +1 or −1 surface defects through which the light incouples/outcouples. The effect of the straight waveguide thickness and the radius of curvature of the curved waveguides on the attenuation of the light in the waveguide is experimentally explored. The experiments are supported with numerical simulations of light propagation through both types of waveguides and outcoupling out of the straight waveguides. Furthermore, the effect of the size of the −1 defect terminations on the outcoupling efficiency is explored using simulations. Based on the presented design and manufacturing approach, liquid crystal optical waveguides of various shapes can be realized accurately with low‐cost. [ABSTRACT FROM AUTHOR]

Surface proton hopping conduction (SPHC) mechanisms is an important proton conduction mechanism in conventional polymer electrolytes, along with the Grotthuss and vehicle mechanisms. Due to the small diffusion coefficient of protons in the SPHC mechanism, few studies have focused on the SPHC mechanism. Recently, it has been found that a dense alignment of SO3− groups significantly lowers the activation energy in the SPHC mechanism, enabling fast proton conduction. In this study, a series of polymerizable amphiphilic‐zwitterions is prepared, forming bicontinuous cubic liquid‐crystalline assemblies with gyroid symmetry in the presence of suitable amounts of bis(trifluoromethanesulfonyl) imide (HTf2N) and water. In situ polymerization of these compounds yields gyroid‐nanostructured polymer films, as confirmed by synchrotron small‐angle X‐ray scattering experiments. The high proton conductivity of the films on the order of 10−2 S cm−1 at 40 °C and relative humidity of 90% is based solely on the SPHC mechanism. [ABSTRACT FROM AUTHOR]

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

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

The development of straightforward and effective methods to determine the topological charge of phase singular beams is crucial for broadening the applications of optical vortices. Here, a straightforward and elegant method for determining the topological charge of an optical vortex using an innovative switchable achromatic nematic liquid crystal Fresnel lens is proposed. The approach allows for the unambiguous determination of both the absolute value and the sign of the topological charge of a singular beam across a wide range of the visible spectrum, as demonstrated both experimentally and theoretically. The research outcomes are promising for applications in optical information transmission systems, cryptography, and quantum computing. [ABSTRACT FROM AUTHOR]

Circularly polarized light is previously shown as a chiral bias to enable the synthesis of chiral plasmonic nanomaterials through light‐matter interactions. The traditional approach for circularly polarized light generation relies on a “top‐down” approach by removing undesired light polarization through optics, which suffers from energy loss and compatibility issues. An alternative approach is to develop chiral phosphors that emit efficient circularly polarized luminescence (CPL). However, most materials fail to produce processable CPL with both high quantum yield and dissymmetry factors, let alone the synthesis of chiral nanomaterials. Herein, a liquid‐crystal‐templated framework is developed to assemble halide perovskite nanocrystals, CsPbX3 (X = Cl, Br, I), and achieved efficient CPL with the record‐high figure of merit (FM) for three primary colors (Red, Green, Blue). The fidelity of the CPL is further demonstrated in the synthesis of chiral gold nanoparticles, where a five‐fold increase in optical activity is achieved. [ABSTRACT FROM AUTHOR]

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

Direct ink writing (DIW) of core‐shell structures allows for patterning hollow or composite structures for shape morphing and color displays. Cholesteric liquid crystal elastomers (CLCEs) with liquid crystal mesogens assembled in a helix superstructure are attractive for generating tunable iridescent structural colors. Here, by fine‐tuning the rheology of the core and shell materials, respectively, this study creates droplets or a continuous filament in the core from the precursors of polydimethylsiloxane (PDMS) or poly(vinyl alcohol), whereas CLCE forms the outer shell. By introducing a dye in the droplets, the skin structures of cephalopods, consisting of chromatophores and iridocytes, are mimicked for enhanced color saturation, lightness, and camouflage. After removal of the core material, a CLCE hollow fiber is obtained, which can switch colors upon mechanical stretching and pneumatic actuation, much like papilla along with iridocytes. Further, liquid crystal mesogens assembled in the bulk of the fiber are in polydomain. Thus, the skin appears opalescent at room temperature, much like how leucophores enhance reflectins. Upon heating above the nematic to isotropic transition temperature, the skin becomes transparent. Lastly, a cephalopod model is constructed, where different parts of the model can change colors independently based on different mechanisms. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (CLCs) with chiral nanostructures take on great significance in light modulation for optical devices, especially involving the features of circularly polarized and dynamic structural colors. However, on‐demand self‐assembly by photoprogramming still remains a challenge that is ascribed to the unpredictable variation of the helical superstructures in the existing CLCs induced by light‐driven chiral switches. Here, novel binary chiral systems are designed to construct visible‐light‐actuated CLCs with multi‐degrees of freedom, including adjustable circular polarization, bidirectional photochromism, and manipulable photonic bands. Such systems consist of an o‐fluoroazobenzene‐containing chiral switch and an inert chiral dopant, whose interaction dominates the strategies of chiral cooperation or conflict to determine the CLC handedness as well as shift direction of the selective reflection. Particularly, the precise tuning range of the structural color is tailored by programmable helical twisting power to enable diverse paradigms of light‐actuated patterning. The unprecedented quantitative manipulation of circularly polarized structural colors offers unique photonic attributes for applications in information encoding and multiplexed communication. [ABSTRACT FROM AUTHOR]

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

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

Over the past 50 years, a principal approach to controlling conventional photochemical reactions has relied on imposing geometric constraints on reactant or transition state via conducting photochemistry in the organized or constraining media. Herein, we describe a fundamentally different approach to affect the course of photochemical reactions (photochemical rearrangements) by utilizing spatially selective excitation of specific electronic transitions with plane‐polarized light in the reactant molecules uniformly aligned in the nematic liquid crystal phase. In particular, we focused on the Type B enone rearrangement of 4,4‐diarylcyclohexenones – one of the most common photochemical rearrangements. We demonstrated that the aryl migratory aptitude in this reaction was attenuated in response to changing an angle between the polarization plane of the incident light and the alignment direction of the nematic liquid crystal, with the enhanced aryl migration achieved when the polarization plane coincided with the transition dipole moment leading to the excited state responsible for this migration. The spatially‐selective initial excitation therefore was overruling the electronic factors responsible for the relative ratio of the two alternative photoproducts. The experimental findings were further supported by the results of a computational study. This work showcases a new fundamental paradigm in controlling photochemical reactivity and selectivity of photoreactions. [ABSTRACT FROM AUTHOR]

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

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

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

Circularly polarized luminescent (CPL) materials have garnered tremendous attention owing to their expanded optical properties beyond emission wavelength and intensity. Among these, the emerging circularly polarized organic ultralong room‐temperature phosphorescence (CP‐OURTP) materialsdemonstrating elegant and distinct features are of significant importance for their extended emission lifetime, which represent a novel frontier in research with promising scientific and technological applications across diverse fields. This review systematically outlines the traditional strategies to achieve CP‐OURTP including organic crystals, copolymerization, host–guest doping, a combination of the copolymerization and host–guest doping, spinning and twisting technology, and supramolecular polymer assembly. Importantly, the recent significant progress of CP‐OURTP in the chiral soft materials, such as liquid crystals (LCs) involving lyotropic LCs (cellulose nanocrystals, CNCs) and chiral thermotropic LCs (cholesteric LCs and chiral LC elastomers), is showcased. Finally, the practical applications of CP‐OURTP materials are summarized, and the review concludes with the perspectives on the current challenges and future opportunities for CP‐OURTP materials. This review aims to inspire the further innovations in the fabrication of advanced CP‐OURTP materials and enrich their promising applications. [ABSTRACT FROM AUTHOR]

Notch filters usually involve high costs, great difficulties in processing, and very limited tunability. By coating a nematic liquid crystal (LC) layer onto a well‐designed quasi‐bound states in the continuum (quasi‐BICs) metasurface, this work designs and demonstrates a high‐Q tunable filtering system with precise tunability in the near‐infrared spectral range. Optimal structural parameters and the filtering performance are first determined by numerical simulations and then confirmed in experiments. The precise tunability is enabled by modifying the LC molecules’ principal axes with an applied voltage, where the least distinguishable central wavelength interval is smaller than 0.3 nm, and the largest Q factor extracted from experiments can be ≈256.1. Compared to most of the commercial notch filters that work in the visible region and have no tunability, this work achieves an ultra‐narrowband filtering system that features low manufacture difficulty and cost, and great control of light propagation. The proposed design also opens new avenues for developing BIC‐based high‐Q devices with enhanced signal‐to‐noise ratio and multifunctional properties. [ABSTRACT FROM AUTHOR]

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

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

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

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

Dichroic dye‐doped liquid crystal (LC) films are extensively developed to mimic the polarization‐dependent coloration found in nature, demonstrating potential applications in various optical devices, like displays. However, despite their remarkable optical anisotropy and functional potential, achieving precise coloration, especially green hues, in dichroic dye‐based films remains challenging due to the inherently broad absorption bands of the dyes. In this study, a straightforward and effective platform is proposed to extend the color gamut of dichroic dye‐doped LC films by utilizing cholesteric liquid crystals (CLCs) as wavelength‐selective polarization modulators. CLCs induce continuous optical rotation across the visible spectrum, enabling modulation of the polarization state of transmitted light. By systematically analyzing the optical properties of CLC, red, and cyan dichroic film‐based trilayer systems, the study demonstrates that simultaneous wavelength‐ and polarization‐selective absorption significantly extends the color gamut beyond that of conventional dichroic films. The findings indicate that the strategic positioning and alignment direction of dichroic films allow for precise control over transmission colors, making it possible to achieve previously unattainable green hues and a wider range of color variations. [ABSTRACT FROM AUTHOR]

We have constructed the phase diagrams in water of two commercial additives for coatings consisting of polyether‐modified polydimethylsiloxanes. These aqueous systems form a liquid crystal mesophase (LC) at copolymer concentrations higher than 60 wt%. At low copolymer concentrations, this LC coexists with a diluted aqueous phase. Small angle x‐ray scattering (SAXS) measurements and polarized optical microscope observations indicate that the structure of the mesophase is lamellar, with an interlayer spacing that increases linearly with the concentration of water in the system. The lamellar liquid crystals display temperature‐dependent viscoelastic behavior, with the copolymer with longer spacing showing a much lower elastic modulus. Since one of the copolymer has terminal acryl groups, its lamellar phase can be crosslinked to produce gelled liquid crystals. Other cross‐linked self‐assembled structures, such as bicontinuous microemulsions, are envisaged. [ABSTRACT FROM AUTHOR]

Polyimide films with low dielectric loss (Df) at high frequencies are urgently needed owing to the rapid development of high‐frequency communication technologies. Herein, various polyimide films with rigid mesogenic units are prepared to address this issue. Improving molecular flexibility has been found to promote crystallization during thermal imidization and, consequently, the formation of liquid‐crystal‐like polyimide (LCPI) films. The optimal LCPI film exhibits an ultralow Df value of 0.00178 at 10 GHz owing to the limited intermolecular friction. Furthermore, this LCPI film absorbs significantly less water (0.59%), which endows it with favorable durability of low Df value in a humid environment. The Df value of the LCPI film at 10 GHz is only 0.00288 after 24 h of exposure to 60% relative humidity. In addition, the LCPI film exhibits a glass transition temperature, coefficient of thermal expansion, and tensile strength of 371 °C, 21.8 ppm K−1, and 240 MPa respectively, and is therefore a suitable low‐dielectric‐material candidate. [ABSTRACT FROM AUTHOR]

Polymer stabilized blue phase (PSBP) liquid crystal has aroused wide attention due to its broad temperature range and potential applications in flexible display, multi‐mode monitor, and mirrorless laser based on its well‐compatible stability and multi‐responsiveness, such as electricity, humidity, and temperature. Temperature produces an important effect on the structure/optical properties of PSBP, but there lack of detailed investigation on thermal‐induced deformation and its influence on the optical performance of PSBP. Here, the thermal‐induced evolution of structure/optical properties of PSBP with different polymer content is in situ characterized by variable‐temperature ultra‐small‐angle X‐ray diffraction, Kossel diffraction, and polarized optical microscopy. A restricted deformation of PSBP cubic lattice is revealed by the shift of reflective wavelength and evolution of Kossel diagrams, which is mainly attributed to the thermal‐induced phase transition/separation of non‐polymerized components. The thermal stability of PSBP is improved by increased polymer content based on the limited deformation ability. This work is significant for the design of novel functional material, which paves the way for the preparation of photonic crystal soft materials with high stability and optical quality. [ABSTRACT FROM AUTHOR]

Endowing artificial muscles with perceptual function, as an octopus does, is highly desired but still suffering from interfacing mismatch between actuating and sensing units in a thin fiber. Herein, an artificial neuromuscular fiber capable of electrically responding to external strain/temperature and actuation path with power supply is reported by using polymer‐assisted metal deposition to firmly coat Cu nanoparticles on the surface of liquid crystal elastomer (LCE). The LCE core acts as an actuator, while the wrinkled Cu sheath provides environment interaction and actuation monitoring. Benefiting from the levodopa/polyethyleneimine interface design, this fiber exhibits large reversible contraction (47.61%), fast strain rate (370% s−1), high output power density (663.75 W kg−1) and reliable durability (1000 cycles) under electrical stimulation. Furthermore, by combining as‐made fiber arrays with electronic system and computing algorithm, this machine learning‐assisted artificial neuromuscular system can actuate the Chinese shadow puppetry and recognize its body movements with high accuracy. This work paves a revolutionary way for fabricating next‐generation flexible robots. [ABSTRACT FROM AUTHOR]

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

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

Vortex‐vector beam generators can effectively improve the channel capacity and communication accuracy, but they face the problems of narrow operating frequency band, low efficiency, and fixed function. Here, a terahertz liquid crystal cascaded metadevice is demonstrated, including a liquid crystal layer, an asymmetric metasurface layer, and a helical phase metasurface layer. The combination of liquid crystal's anisotropy and structural anisotropy from the asymmetric metasurface realizes the dynamic chirality construction. Then, the tunable chiral fields are effectively coupled with the helical geometric phase of the last metasurface layer to realize an active control between symmetric and asymmetric spin‐orbit angular momentum coupling, leading to the two types of beam generation and conversion: 1) spin‐dependent conversion and energy distribution between the vortex beams with ±2 topological charges; 2) the conversions between the 2‐order vortex beam and the cylindrical vector beam. The experimental results show that the excitation efficiency of vortex beams can reach over 92.1%, and the intensity modulation depth between different types of beams is more than 72.4%. This THz beam dynamic conversion mechanism and device scheme increase the degree of freedom of the device and have potential applications in terahertz multi‐channel wireless communication, polarization multiplexing imaging, and chiral spectrum detection. [ABSTRACT FROM AUTHOR]

Orientational ordered soft matter possessing diverse microstructures has become a focal point of scientific research and technological exploration, thanks to its advancements in serving as an indispensable optical platform enabling propagation of light with multidimensional and manipulatable states. Herein, a facile way is developed to manipulate the in‐plane light beam transition dynamics by harnessing a time‐variable nematic liquid crystal (NLC) film through the electrical‐field‐induced topological defects. The results show that the dynamic change of optical branched flow is associated with the growth in the correlation length of optical potential and the reduction in the density of topological defects. The optical branching can continuously transform to deterministic and tunable beam steering at the low‐defect‐density regime through annihilation kinetics of defects. The explored soft matter system provides an excellent planar platform for the fundamental physics of light interacting with topological defects and may offer new perspectives for novel optics elements toward the applications of soft matter photonics. [ABSTRACT FROM AUTHOR]

Optical encryption is an increasingly significant technique in the realm of information security. In the recent decade, there has been considerable interest in using planar optics elements for information encryption. However, information leakage possibly occurs due to limited encrytion channels available for single‐layer devices. To circumvent this problem, a novel encryption method is put forward using secret sharing cascaded liquid crystal (LC) elements with spatial dislocation, which can produce near‐field patterns and far‐field holographic images under different illumination conditions. Specifically, Malus's Law and its inherent one‐to‐four mapping of rotational degeneracy, along with the Pancharatnam‐Berry (PB) phase introduced by LC molecules, to achieve multi‐channel encryption are utilized. Therefore, each cascaded LC unit can manipulate the amplitude and phase imparted to output light independently, thus only by obtaining both LC devices can decryption be realized. To further enhance the encryption security, the author purposely divide each LC device into multiple regions and find that the encrypted patterns can only be recovered when the two LC elements align precisely with a specific dislocation. These experimental measurements agree well with the design, thus demonstrating the strong encryption capability and broad application prospects of the design approach in the field of optical encryption with high cost‐effectiveness. [ABSTRACT FROM AUTHOR]

The work deals with the Ericksen–Leslie system for nematic liquid crystals on the space RN$\mathbb {R}^N$ with N≥3$N\ge 3$. In our work, we suppose the initial condition v0$v_0$ stays on an arc connecting two fixed orthogonal vectors on the unit sphere. Thanks to this geometric assumption, we prove through energy a priori estimates the local existence and the global existence for small initial data of a solution u∈L∞((0,T);Hs(RN)),∇u∈L2((0,T);Hs(RN)),$$\begin{equation*} \hspace*{60pt}u\in L^\infty ((0,T);H^s(\mathbb {R}^N)),\quad \nabla u\in L^2((0,T);H^s(\mathbb {R}^N)), \end{equation*}$$∇v∈L∞((0,T);Hs(RN)),∇2v∈L2((0,T);Hs(RN))$$\begin{equation*} \hspace*{55pt}\nabla v\in L^\infty ((0,T);H^s(\mathbb {R}^N)),\quad \nabla ^2v\in L^2((0,T);H^s(\mathbb {R}^N)) \end{equation*}$$for s>N2−1$s>\frac{N}{2}-1$, asking low regularity assumptions on u0$u_0$ and v0$v_0$. [ABSTRACT FROM AUTHOR]

Polar liquid crystals possess 3D orientational order coupled with unidirectional electric polarity, yielding fluid ferroelectrics. Such polar phases are generated by rod‐like molecules with large electric dipole moments. 2,5‐Disubstituted 1,3‐dioxane is commonly employed as a polar motif in said systems, and herein it is shown to suffer from thermal instability as a consequence of equatorial‐trans to axial‐trans isomerism at elevated temperatures. Isosteric building blocks are utilized as potential replacements for the 1,3‐dioxane unit, and in doing so new examples of fluid ferroelectric systems are obtained. For binary mixtures of certain composition, the emergence of a new fluid antiferroelectric phase, a finding not observed for either of the parent molecules, is observed. This study also reveals a critical tipping point for the emergence of polar order in otherwise apolar systems. These results hint at the possibility for uncovering new highly ordered polar liquid‐crystalline phases and delineate distinct transition mechanisms in orientational and polar ordering. [ABSTRACT FROM AUTHOR]

4D printing is an advanced technology that integrates the mechanics design and active materials into 3D printing to create objects with time‐evolving transformation. However, the commonly used active materials, such as shape memory polymers or hydrogels, make it challenging to simultaneously realize two‐way shapeshifting and high stiffness in 4D printed structures, constraining its application in engineering areas such as robotics, morphing structures, etc. Herein, inspired by human musculoskeletal structure, a 4D printing strategy that integrates two‐way shapeshifting liquid crystal elastomer and amorphous shape memory polymer to realize reversible actuation and tunable stiffness via sequential thermal control is proposed. Through numerical analysis and experimental investigation, the mapping relationship among structural deformation, material property, and geometric design is established, allowing to seek out the optimized thickness ratio and material properties that lead to high shape fixity (81%) and complete shape recovery (100%). To demonstrate the potential applications, a variable stiffness hook capable of wrapping and lifting heavy objects through helical transformation is realized. This design strategy can potentially inspire the development of 4D printing toward load‐bearing soft machines. [ABSTRACT FROM AUTHOR]

Electroactive liquid crystal elastomers (eLCEs) are used to make actuators and soft robotics. However, most eLCEs are monofunctional with one type of deformation (bending or contraction). Recently, a trilayer eLCE are reported by combining ion‐conducting LCE and ionic electroactive polymer device (i‐EAD). This i‐EAD‐LCE is bifunctional and performs either bending or contractile deformation by controlling low‐voltage stimulation. Nevertheless, it has a Young's modulus of only 1.63 MPa. To improve the mechanical performance, the i‐EAD‐IPN‐LCE is prepared here, whose central membrane is composed of interpenetrating LCE and ionogel (i‐IPN‐LCE) instead of a single ion‐conducting LCE. This i‐EAD‐IPN‐LCE with a typical thickness of 0.5 mm can function not only as linear and bending actuators, but also as a sensor. As a linear actuator, its Young's modulus, actuation stress, and strain are 51.6 MPa, 0.14 MPa and 9%, respectively, reaching skeletal muscles' values. As a bending actuator, its bending strain difference Δε is 1.18% with 3 mN output force. It can also operate as a sensor producing 0.4 mV Open‐Circuit‐Voltage to respond to bending deformation (Δε = 9%). Therefore, this i‐EAD‐IPN‐LCE is a promising system for the fabrication of robust electroactive devices and sensors with multiple degrees of freedom. [ABSTRACT FROM AUTHOR]

Aquatic insects have developed versatile locomotion mechanisms that have served as a source of inspiration for decades in the development of small‐scale swimming robots. However, despite recent advances in the field, efficient, untethered, and integrated powering, actuation, and control of small‐scale robots remains a challenge due to the out‐of‐equilibrium and dissipative nature of the driving physical and chemical phenomena. Here, we have designed small‐scale, bioinspired aquatic locomotors with programmable deterministic trajectories that integrate self‐propelled chemical motors and photoresponsive shape‐morphing structures. A Marangoni motor system is developed integrating structural protein networks that self‐regulate the release of chemical fuel with photochemical liquid crystal network (LCN) actuators that change their shape and deform in and out of the surface of water. While the diffusion of fuel from the motor system regulates the propulsion, the dissipative photochemical deformation of LCNs provides locomotors with control over the directionality of motion at the air‐water interface. This approach gives access to five different but interchangeable modes of locomotion within a single swimming robot via morphing of the soft structure. The proposed design, which mimics the mechanisms of surface gliding and posture change of semiaquatic insects such as water treaders, offers solutions for autonomous swimming soft robots via untethered and orthogonal power and control. [ABSTRACT FROM AUTHOR]

In this study, a new assembly strategy for lyotropic chromonic liquid crystals (LCLCs) is proposed using iπ–iπ interactions, mainly comprising electrostatic and dispersion forces, between charged π‐electronic systems to form stacking structures supported by the hydration of triethylene glycol (TEG) units. The meso‐TEG‐aryl‐substituted porphyrin AuIII complex, an amphiphilic π‐electronic cation, showed diverse states and assembly modes in ion pairs depending on the coexisting counteranions. The PCCp− ion pair formed a hexagonal columnar (Colh) LC phase based on a charge‐by‐charge assembly, suggesting the formation of an ordered arrangement of charged π‐electronic systems through iπ–iπ interactions, with reduced interactions between the TEG chains. Furthermore, in the presence of water, LCLC behavior in the Colh and nematic columnar phases according to the amount of water were observed for the PCCp− ion pair as a result of iπ–iπ interactions. Magnetic‐field‐induced orientation of the charge‐by‐charge columnar structures upon dehydration was observed. Furthermore, single‐stranded charge‐by‐charge columnar structures, as components of the LCLCs, were observed using transmission electron microscopy (TEM). [ABSTRACT FROM AUTHOR]

Viologen‐based reactive mesogen (VRM) is newly designed and synthesized for the development of polarization‐dependent, color‐tunable, and transparent electrochromic (EC) smart windows. By controlling electric field, the color of VRM can be intentionally tuned due to the formation of dication (D state), cation‐radical (C state), and neutral state (N state). Based on the deep understanding of phase transition of VRM, a uniaxially oriented VRM hierarchical nanostructure is successfully constructed on the macroscopic area by simple coating and self‐assembly processes. The subsequent photopolymerization significantly improves thermal, mechanical, and chemical stabilities of the VRM thin film. In addition to the control of color, the transmittance of uniaxially oriented VRM‐based EC smart window can be precisely tuned by rotating a linear polarizer. [ABSTRACT FROM AUTHOR]

4D printing has attracted widespread attention due to its ability to fabricate complex structures capable of responding to specific stimuli. However, existing smart materials used for 4D printing, such as conventional hydrogels, liquid crystal elastomers, and shape‐memory polymers, are constrained in their ability to fulfill both mechanical ultrastrength and ultrastretchability requirements simultaneously due to their water saturation or uneven network structures. This study presents 4D printing of liquid‐free ionic elastomers (LFIEs) that is achieved through photopolymerization of the acrylic acid‐tetramethylammonium chloride‐polymerizable deep eutectic solvent. The transition temperature (Tt) of the high‐fracture‐strength LFIEs is adjusted by introducing phenylphosphoric acid, harboring multiple hydrogen‐bonds, leading to improved molecular chain mobility through softening of the chains. Consequently, the 4D‐printed LFIEs retain their high strength while achieving ultrastretchable properties even under elevated temperatures during heating. Moreover, the 4D‐printed LFIEs demonstrate both a swift response time and a high fixation rate even after undergoing repeated transformation cycles. These outstanding capabilities exhibit by LFIEs present a reliable strategy for advancing their applications in diverse fields, such as smart furniture, robotics, and intelligent manufacturing with remote monitoring, and beyond. [ABSTRACT FROM AUTHOR]

Here we report the design, synthesis, and photoresponsive behavior of supramolecular liquid crystalline (LC) materials based on benzenetricarboxamide and di‐ortho substituted azobenzene. Differential scanning calorimetry, polarized optical microscopy, and wide‐angle X‐ray scattering studies confirm the formation of columnar tetragonal mesophase at room‐temperature. Photoisomerization studies reveal the visible light responsiveness of compounds in solution. Furthermore, we demonstrate supramolecular gel formation, which undergoes irreversible gel‐sol transformation upon blue light irradiation, highlighting its potential for light‐triggered applications in the field of drug delivery, energy storage etc. [ABSTRACT FROM AUTHOR]

Reaction of the phenolate or naphthalen‐2‐olate based Schiff base ligands, (E)‐1‐((2‐ethylphenylimino)methyl)phenol (HL1) or (E)‐1‐((2‐ethylphenylimino)methyl)naphthalen‐2‐ol (HL2) with nickel(II) and copper(II) acetate provides the complexes bis[(E)‐1‐((2‐ethylphenylimino)methyl)phenolato‐ĸ2N,O]Ni/Cu(II), [Ni(L1)2] (1) and [Cu(L1)2] (2), or bis[(E)‐1‐((2‐ethylphenylimino)methyl)naphthalen‐2‐olato‐ĸ2N,O]Ni/Cu(II), [Ni(L2)2] (3) and [Cu(L2)2] (4), respectively. Single crystal X‐ray structure determinations for 1, 3 and 4 reveal N2,O2‐metal coordination of two chelating Schiff base ligands in a square‐planar geometry. Powder X‐ray diffractograms confirm the phase purity of the bulk microcrystalline samples. Thermal analyses by differential scanning calorimetry (DSC) and polarized light microscopic (PLM) indicate the copper(II) complexes to exhibit cold crystal (2) and liquid crystal (4) property. Cyclic voltammograms suggest an irreversible electrochemical process with two one electron charge transfer processes in N,N‐dimethylformamide. Variable temperature magnetic measurements at the solid‐state prove the diamagnetic nature of the low‐spin Ni2+ centres in 1 or 3, as expected from the square‐planar coordination geometry with rather strong ligands. The complexes expose medium level of antioxidant activity in methanol. Optimized geometry and excited state property by DFT/TD‐DFT correspond well to the experimental results of the electronic and molecular structure at the ground state. [ABSTRACT FROM AUTHOR]

In this paper, electrically responsive liquid crystal network (LCN) based soft actuators are presented that can achieve large deformations under an alternating current (AC) electric field. These LCN actuators are prepared by photopolymerization of liquid crystal acrylate monomers with polar end groups, which form polar side chains in the networks. Actuation is initiated by applying a high‐frequency and low‐voltage electric field. When this AC field is applied, the LC mesogens, especially the polar side chains, can oscillate, decreasing the molecular order, and creating free volume in the LCNs, which further results in anisotropic deformation. The formed shapes range from bending to bulging, depending on the programmed molecular alignment. The actuation proceeds fast within 5 s both for activation and for the relaxation to the initial state upon switching the power on and off. This LCN soft actuator exhibits fast response, low power consumption, and high precision, making it a promising candidate for applications in soft robotics, microfluidics, and biomimetic muscles. [ABSTRACT FROM AUTHOR]

Direct viscous mechano‐electric response is demonstrated for a room‐temperature ferroelectric nematic liquid, which combines large spontaneous electric polarization with 3D fluidity. The mechano‐electric transduction is observed in the frequency range 1 −200 Hz via a simple demonstrator device. The liquid is placed into a deformable container with electrodes and the electric current induced by both periodic and irregular actuation of the container is examined. The experiments reveal a rich interplay of several distinct viscous mechano‐electric phenomena, where both shape deformations and material flow cause changes in the electric polarization structure of a ferroelectric nematic liquid. The results show that the mechano‐electric features of the material promise a considerable applicative perspective spanning from sensitive tactile sensors to energy harvesting devices. [ABSTRACT FROM AUTHOR]

Smart windows have come to the fore in modern buildings and intelligent information equipment drawing upon their dynamic control over light transmission. Liquid crystals tactfully manipulate light transmission depending on their microcosmic molecular orientations, emerging as new favorite functional materials for smart windows. However, most liquid crystal window technologies require continuous electricity for operation in luminous transparency and still perform a trade‐off between film formation performance and dimming functions. As key components of building structures, windows shall be kept transparent for an extended period. For the convenience of large‐scale processing, polymer matrices are indispensable. Given that, reverse‐operation‐mode dimming films, which are transparent to achieve daylighting in their natural or no power‐input states and become opaque to block sunlight through electric input on demand, are highly desired. Here, by introducing a photolabile amine, the synchronous light‐induced formation of polymer networks and enhancement of electrohydrodynamic instabilities in mesogenic materials is successfully executed. Relying on this creative and effective approach, reverse‐operation‐mode polymer network liquid crystal films having simultaneous modulation capability of visible light and near‐infrared light from solar irradiation are skillfully fabricated, promising applications in versatile energy‐saving smart windows. [ABSTRACT FROM AUTHOR]

The reversible modulation of chirality has gained significant attention not only for fundamental stereochemical studies but also for numerous applications ranging from liquid crystals (LCs) to molecular motors and machines. This requires the construction of switchable molecules with (multiple) chiral elements in a highly enantioselective manner, which is often a significant synthetic challenge. Here, we show that the dimerization of an easily accessible enantiopure planar chiral ferrocene‐indanone building block affords a multi‐stimuli‐responsive dimer (FcD) with pre‐determined double bond geometry, helical chirality, and relative orientation of the two ferrocene motifs in high yield. This intrinsically planar chiral switch can not only undergo thermal or photochemical E/Z isomerization but can also be reversibly and quantitatively oxidized to both a monocationic and a dicationic state which is associated with significant changes in its (chir)optical properties. Specifically, FcD acts as a chiral dopant for cholesteric LCs with a helical twisting power (HTP) of 13 μm−1 which, upon oxidation, drops to near zero, resulting in an unprecedently large redox‐tuning of the LC reflection color by up to 84 nm. Due to the straightforward stereoselective synthesis, FcD, and related chiral switches, are envisioned to be powerful building blocks for multi‐stimuli‐responsive molecular machines and in LC‐based materials. [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]

Liquid crystal elastomer (LCE) has large and reversible deformation under stimulation, making it an ideal material for artificial muscles. Currently, multi‐stimulus responsive LCE actually responds to each stimulus independently rather than responding to several stimuli simultaneously. Achieving an enhanced effect from concurrent stimuli is still a challenge, which requires a new stimulus‐response mechanism. This work develops a novel and facile solvent evaporation‐assisted template method to prepare LCE hollow fiber (LCEHF) with axial alignment. Taking advantage of the enhanced effect of heat‐induced phase transition and mechanical force‐induced orientation transition of mesogens, the LCEHF under both heat and pressure can produce a large contraction ratio of ≈50%, which is higher than 42% of thermal stimulation or 27% of pneumatic stimulation. It can also enhance the respective response and recovery speed of LCEHF to 300 and 3700 times of pneumatic actuation. Additionally, the enhanced effect lowers the actuation temperature much below the phase transition temperature, imparting LCEHF with high mechanical performance during actuation. Furthermore, the dual thermal‐pneumatic responsive LCEHF can mimic human biceps and cause large and rapid bending of an artificial arm reversibly. This new actuation methodology sheds new light on improving LCE actuation performance and broadens its application scenarios. [ABSTRACT FROM AUTHOR]

Passive radiative cooling materials can efficiently reflect solar radiation and spontaneously dissipate heat through the long‐wave infrared (LWIR) transmission window to the coldouter space. They are highly attractive for application in walls and roofs of sustainable energy‐efficient buildings, but it is a challenging task to develop switchable radiative coolers for transparent windows. Herein, free‐standing bacterial cellulose‐templated radiative cooling liquid crystal films with high LWIR emissivity and self‐adaptive solar transmittance are reported. Biosynthetic silanized bacterial cellulose with 3D interconnected porous nanostructure is harnessed as a robust template for confining novel liquid crystals with smectic A to chiral nematic phase transition, thereby endowing the film with high solar transmittance modulation ability. The resulting film is found to not only exhibit a remarkable LWIR emissivity, but also adaptively change its solar transmittance between a transparent state and an opaque state according to environmental temperature variation. Outdoor radiative cooling experiments are performed, and the energy‐saving performance is evaluated through a simulation of a 12‐story reference office building with the films applied as radiative cooling windows. This research can shine light on the development of advanced radiative cooling materials with switchable transmittance and their widespread applications in buildings, vehicles, and transparent photovoltaics. [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]