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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 electro-optic response of polymer stabilised cholesteric liquid crystals can manifest as switching, tuning, or bandwidth broadening. The electro-optic response of these composites is attributed to the delocalisation of the ion-containing, structurally chiral polymer stabilising network to a DC bias. Upon removal of the electric field, the original reflective properties return within seconds. Prior reports have hypothesized that the polymer network trap ionic impurities during polymerization. Here, we explore this hypothesis by introducing ionic liquids as well as copolymerizing ionic monomers into the polymer network. This work further elucidates the contribution of ionic species to the electrochemical properties of the composite material as well as the associated impact on electro-optic performance. [ABSTRACT FROM AUTHOR]

The selective reflection inherent to the cholesteric liquid crystal (CLC) phase (in the planar orientation) can be tuned or broadened by the incorporation of polymer stabilizing networks (PSCLC). Prior reports detail that the mechanism is ion-mediated deformation of the polymer stabilizing network, which retains structural chirality. The structural chirality of the polymer stabilizing effectively overpowers the chirality of the CLC mixture. Here, we incorporate monomers containing groups known to trap cationic metal halide ions, into the polymer stabilizing network. Specifically, we incorporate monofunctional control monomers as well as monofunctional acrylate monomers 4-acryloxyhexylterpyridine (TPy-Ac), 4-((6-(acryloyloxy)hexyl)oxy)benzoic-15-crown-5 (OBA-15C5), and 4-((6-(acryloyloxy)hexyl)oxy)benzoic-18-crown-6 (OBA-18C6). The electro-optic response is enhanced only by the inclusion of OBA-15C5 which previously has been shown to selectively trap and interact with sodium (Na+) ions. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCEs) that retain the cholesteric phase (CLCEs) are soft, polymeric materials that retain periodic structure and exhibit a selective reflection. While prior studies have examined thermochromism in CLCEs, the association of temperature change and reflection wavelength shift has been limited to 1.4 nm °C−1. Here, CLCEs with intra‐mesogenic supramolecular bonds are prepared to enhance tunability as well triple the rate (e.g., 4.8 nm °C−1). Specifically, these materials incorporate liquid crystalline monomers based on dimerized oxy‐benzoic acid (OBA) derivatives. Increasing the concentration of the OBA comonomers increases the magnitude of red‐shifting thermochromism of the selective reflection. At and above a threshold concentration, the selective reflection in the CLCEs can disappear upon heating, analogous to on‐off "switching." Further, the introduction of the supramolecular bonds within the CLCE enable mechanical programming and enhanced one‐time tunable thermochromism via a one‐way shape memory process. Accordingly, this research could enable functional use in low temperature sensitive optical elements, fail‐safe thermal indicators for food packaging, and smart window coatings. [ABSTRACT FROM AUTHOR]

Highlights: Recent advances in the metal–organic framework (MOF)-related catalysts for electrochemical ammonia synthesis protocols under ambient reaction conditions are summarized and discussed. The design and fabrication of efficient electrocatalysts from MOF for the reduction of N2 and NO3− are systematically analyzed. Based on the current advances, the ongoing challenges and promising perspectives are highlighted. Electrocatalytic synthesis under mild conditions has become increasingly important as one of the practical alternatives for industrial applications, especially for the green ammonia (NH3) industry. A properly engineered electrocatalyst plays a vital role in the realization of superior catalytic performance. Among various types of promising nanomaterials, metal–organic frameworks (MOFs) are competitive candidates for developing efficient electrocatalytic NH3 synthesis from simple nitrogen-containing molecules or ions, such as N2 and NO3−. In this review, recent advances in the development of electrocatalysts derived from MOFs for the electrosynthesis of NH3 are collected, categorized, and discussed, including their application in the N2 reduction reaction (NRR) and the NO3− reduction reaction (NO3RR). Firstly, the fundamental principles are illustrated, such as plausible mechanisms of NH3 generation from N2 and NO3−, the apparatus of corresponding electrocatalysis, parameters for evaluation of reaction efficiency, and detection methods of yielding NH3. Then, the electrocatalysts for NRR processes are discussed in detail, including pristine MOFs, MOF-hybrids, MOF-derived N-doped porous carbons, single atomic catalysts from pyrolysis of MOFs, and other MOF-related materials. Subsequently, MOF-related NO3RR processes are also listed and discussed. Finally, the existing challenges and prospects for the rational design and fabrication of electrocatalysts from MOFs for electrochemical NH3 synthesis are presented, such as the evolution of investigation methods with artificial intelligence, innovation in synthetic methods of MOF-related catalysts, advancement of characterization techniques, and extended electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

The combination of enzymes and chemically responsive smart materials presents considerable opportunities in anti‐fouling, sensing or medicine. Among stimuli‐responsive polymers, liquid crystal elastomers (LCEs) have emerged as a leading actuator platform due to their inherent programmability, realizing large shape transformations upon exposure to stimuli. Herein, three different hydrolytic enzymes are immobilized into acid‐responsive LCEs, which impart the LCEs with sensitivity to three distinctive classes of biomolecules: lipids, carbohydrates, and peptides. Dye‐doped biocatalytic LCEs readily switch their color and shape upon exposure to the appropriate substrate. Twisted nematic patterning and direct ink writing are used to showcase the versatility of shape changes the enzyme‐containing LCEs may undergo. Multiplexed responsiveness is also demonstrated using a connected array of 3D printed disks, each containing a different enzyme, highlighting the excellent chemical selectivity of the LCEs. This work presents a novel platform of versatile bioresponsive color‐switchable actuators that may have application in a wide range of fields. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCE) are thermally cyclable, compliant actuators with compelling mechanical properties. The large and programmable deformation of LCE has led to numerous functional examinations spanning optics, medical devices, and robotics. A well‐established method to prepare complex LCE actuators is to utilize surface‐enforced photoalignment. Herein, a facile and scalable approach is reported to circumvent the physical limits of surface‐enforced alignment (e.g., samples that are 50 µm or less) to amplify the achievable force output in LCE. Applying an approach termed direct layering, the thermomechanical response of LCE elements prepared with +1 disclination patterns in a range of compositions and thicknesses is contrasted. The design and preparation of +1 disclination patterns and arrays is explored to assess the contribution of sample geometry and overlap to deformation and force output. The methodology detailed in this contribution allows for the preparation of elements ≈1 mm in thickness that are capable of actuating large objects. Furthermore, the fabrication of these elements uniquely enables the realization of mechanical instabilities to hasten the actuation rate in response to thermal change and to enable leaping. [ABSTRACT FROM AUTHOR]

A mixed passivation strategy is deployed to produce monodisperse and pure CsPbBr3 nanocrystals under ambient condition via post treatment using ZnBr2 in mixed organic solvents. This room temperature synthesis route provides precise size and shape control, and colloidal nanocubes or nanospheres can be obtained depending on the choice of organic solvents. Any secondary phases' nucleation was inhibited. The ZnBr2 can reduce the Br− vacancies at the surface termination layers, thus enhancing their properties. This approach can potentially offer a cheap and viable route for perovskite nanocrystals in optical and electrical devices. [ABSTRACT FROM AUTHOR]

Perovskite-related materials show very promising properties in many fields. Pb-free perovskites are particularly interesting, because of the toxicity of Pb. In this study, hybrid double perovskite MA2KBiCl6 (MA = methylammonium cation) was found to have interesting variable temperature behaviours. Both variable temperature single crystal X-ray diffraction, synchrotron powder diffraction, and Raman spectroscopy were conducted to reveal a rhombohedral to cubic phase transition at around 330 K and an order to disorder transition for inorganic cage below 210 K. [ABSTRACT FROM AUTHOR]

Electrochromic devices have seen widespread adoption in the automotive and aerospace industries and are increasingly considered for applications in the built environment, such as smart windows. Here, a distinctive approach is reported to realizing electrochromism in solid, polymeric materials. The optical elements are based on liquid crystalline elastomers (LCEs) that retain the cholesteric phase (CLCEs). By integrating flexible, optically transparent, and conductive electrodes the CLCEs are actuated as dielectric elastomer actuators. Application of an electric field causes a significant change in the reflection wavelength of fully solid CLCE. The electromechanical response (Maxwell stresses) is reversible. Both uniaxial and biaxial prestrain are shown to enhance and differentiate the stimuli‐response in the photonic device. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCEs) are stimuli‐responsive materials capable of undergoing large deformations. The thermomechanical response of LCEs is attributable to the coupling of polymer network properties and disruption of order between liquid crystalline mesogens. Complex deformations have been realized in LCEs by either programming the nematic director via surface‐enforced alignment or localized mechanical deformation in materials incorporating dynamic covalent chemistries. Here, the preparation of LCEs via thiol‐Michael addition reaction is reported that are amenable to surface‐enforced alignment. Afforded by the thiol‐Michael addition reaction, dynamic covalent bonds are uniquely incorporated in chemistries subject to surface‐enforce alignment. Accordingly, LCEs prepared with complex director profiles are able to be programmed and reprogrammed by (re)activating the dynamic covalent chemistry to realize distinctive shape transformations. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers (LCE) are an emerging class of material actuators. LCE undergo macroscopic dimensional changes when subjected to a stimulus. The large stimuli‐response of LCE is associated with thermotropic disruption of order. Historically, comparatively high temperatures are required to disrupt orientation in LCE to achieve meaningful work output. Here, we introduce an approach to prepare LCE via thiol‐Michael/thiol–ene reactions that actuate at or below ambient temperature. Alignment was imparted to the LCE by mechanical alignment and 3D printing. The LCE materials detailed here achieve strains of 40 % with a maximum deformation rate of 6.5 % °C−1. The functional utility of the tunability of the thermotropic response of these materials is illustrated in reconfiguration triggered via body heat and sequential actuation of a multi‐material element. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers (LCE) are an emerging class of material actuators. LCE undergo macroscopic dimensional changes when subjected to a stimulus. The large stimuli‐response of LCE is associated with thermotropic disruption of order. Historically, comparatively high temperatures are required to disrupt orientation in LCE to achieve meaningful work output. Here, we introduce an approach to prepare LCE via thiol‐Michael/thiol–ene reactions that actuate at or below ambient temperature. Alignment was imparted to the LCE by mechanical alignment and 3D printing. The LCE materials detailed here achieve strains of 40 % with a maximum deformation rate of 6.5 % °C−1. The functional utility of the tunability of the thermotropic response of these materials is illustrated in reconfiguration triggered via body heat and sequential actuation of a multi‐material element. [ABSTRACT FROM AUTHOR]

Diarylethene‐functionalized liquid‐crystalline elastomers (DAE‐LCEs) containing thiol‐anhydride bonds were prepared and shown to undergo reversible, reprogrammable photoinduced actuation. Upon exposure to UV light, a monodomain DAE‐LCE generated 5.5 % strain. This photogenerated strain was demonstrated to be optically reversible over five cycles of alternating UV/Visible light exposure with minimal photochrome fatigue. The incorporation of thiol‐anhydride dynamic bonds allowed for retention of actuated states. Further, re‐programming of the nematic director was achieved by heating above the temperature for bond exchange to occur (70 °C) yet below the nematic‐to‐isotropic transition temperature (100 °C) such that order was maintained between mesogens. The observed thermal stability of each of the diarylethene isomers of over 72 h allowed for decoupling of photo‐induced processes and polymer network effects, showing that both polymer relaxation and back‐isomerization of the diarylethene contributed to LCE relaxation over a period of 12 hours after actuation unless bond exchange occurred. [ABSTRACT FROM AUTHOR]

Diarylethene‐functionalized liquid‐crystalline elastomers (DAE‐LCEs) containing thiol‐anhydride bonds were prepared and shown to undergo reversible, reprogrammable photoinduced actuation. Upon exposure to UV light, a monodomain DAE‐LCE generated 5.5 % strain. This photogenerated strain was demonstrated to be optically reversible over five cycles of alternating UV/Visible light exposure with minimal photochrome fatigue. The incorporation of thiol‐anhydride dynamic bonds allowed for retention of actuated states. Further, re‐programming of the nematic director was achieved by heating above the temperature for bond exchange to occur (70 °C) yet below the nematic‐to‐isotropic transition temperature (100 °C) such that order was maintained between mesogens. The observed thermal stability of each of the diarylethene isomers of over 72 h allowed for decoupling of photo‐induced processes and polymer network effects, showing that both polymer relaxation and back‐isomerization of the diarylethene contributed to LCE relaxation over a period of 12 hours after actuation unless bond exchange occurred. [ABSTRACT FROM AUTHOR]

The blue phases are observed in highly chiral liquid crystalline compositions that nascently organize into a three-dimensional, crystalline nanostructure. The periodicity of the unit cell lattice spacing is on the order of the wavelength of visible light and accordingly, the blue phases exhibit a selective reflection as a photonic crystal. Here, we detail the synthesis of liquid crystalline elastomers that retain blue phase I, blue phase II, and blue phase III. The mechanical properties and optical reconfiguration via deformation of retained blue phases are contrasted to the cholesteric phase in fully solid elastomers with glass transition temperatures below room temperature. Mechanical deformation and chemical swelling of the lightly crosslinked polymer networks induces lattice asymmetry in the blue phase evident in the tuning of the selective reflection. The lattice periodicity of the blue phase elastomer is minimally affected by temperature. The oblique lattice planes of the blue phase tilt and red-shift in response to mechanical deformation. The retention of the blue phases in fully solid, elastomeric films could enable functional implementations in photonics, sensing, and energy applications. Permanently retaining liquid crystalline blue phases in a solid matrix warrants many prospective applications in photonics. Schlafmann and White are able to make a blue phase rubber that retains a crystalline structure upon deformation and responds with angle-dependent color changes. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCE) are stimuli‐responsive materials with a distinguished mechanical response. LCE have been subject to numerous recent functional examinations in robotics, health sciences, and optics. The liquid crystallinity of the elastomeric polymer networks of LCE are largely derived from liquid crystalline monomer precursors. Recent reports have utilized commercially available liquid crystalline diacrylate monomers in chain extension reactions to prepare LCE. These reactions have been largely based on monomeric precursors originally to enhance the and thermal stability of optical films. Here, it is demonstrated that preparing LCE via a liquid crystalline diacrylate with reduced mesogen–mesogen interaction enhances and sharpens the thermotropic actuation of these materials. Robust composition‐response correlations are demonstrated in LCE prepared by three common synthetic methods. The enhanced thermotropic response of LCE prepared from this precursor increases the thermomechanical efficiency by sixfold. Accordingly, this work addresses important limitations in utilizing the thermal response of LCE in robotics, health care, and consumer goods. [ABSTRACT FROM AUTHOR]

The growing interaction between local cultures and international organisations suggests the need for peacebuilders to act strategically when trying to overcome cultural differences and build trust in societies long divided by bloody conflicts. This task is more difficult because the mental barriers that divide people and cultures are exacerbated by borders and walls. Through an analysis of the evolving role of the European Union (EU) in peacebuilding in the border region of Ireland, this forum contribution examines the potential of international organisations to enhance reconciliation by creating new cultural opportunities for cooperation. Existing scholarship focuses mainly on policy initiatives, strategies, directives and funding bodies, often failing to mention how theories are deployed by practitioners especially in the realm of cultural programmes. [ABSTRACT FROM AUTHOR]

Electrical reconfiguration of the cholesteric liquid crystal phase is subject to extensive prior research. Here, a distinctive composition that allows the typically singular selective reflection to be split into two distinct and tunable selective reflections with an electric field is reported. The distinctive electro‐optic phenomena (reflection notch splitting) are shown to be composition dependent and enabled by the introduction of appreciable amounts of side chain liquid crystalline mesogens. Functional opportunities enabled by the distinguished control of the two reflection elements are demonstrated, including spectrally variant polarization filters. [ABSTRACT FROM AUTHOR]

A mechanochromic, programmable, cholesteric liquid crystalline elastomer (CLCE) is fabricated, and after straining, resulting in a blue shift through the visible spectrum, is returned to its initial shape and color upon heating through its isotropic phase transition. Light initiated, radical‐mediated, addition fragmentation chain transfer (AFT), facilitate permanent programming or erasure of thermoreversible shape and color by relaxing stress imparted on the strained network through reversible bond exchange. Thermoreversible strain is coupled with reversible color change and can be made permanent at any desired strain by light exposure and corresponding AFT activation, temporarily restoring nearly initial shape and color upon heating. The optical characteristics and photonic structure, inherently linked to the network, are measured as a function of strain, to confirm the reflection notch narrowing indicating that prepolymerization alignment via shearing is poor thereby causing a broad spectrum of reflected light that narrows when the material is stretched. Beyond programming a new shape and color, the reflection notch is erased and separately, photopatterned to achieve dynamic color schemes that are toggled with heating and cooling, similar to that of a chameleon's camouflaging technique that has the ability to manipulate multiple colors in a single material, also with use for strain mapping. [ABSTRACT FROM AUTHOR]

Chilaiditi's syndrome is a rare and often asymptomatic anomaly, typically found as an incidental radiographic sign (gas under the diaphragm) due to hepato-diaphragmatic interposition of the transverse colon. We report a case of Chilaiditi's syndrome following colonoscopy presenting with severe abdominal pain, dyspnoea and radiograph findings similar to the presence of bowel perforation (appearance of gas under the hemidiaphragm on erect chest radiograph). Computed tomography (CT) evidence of Chilaiditi's sign prevented unnecessary laparotomy. [ABSTRACT FROM AUTHOR]

Pancreatic pseudocysts are a known complication of pancreatitis. There are a multitude of complications which have been described in relation to pancreatic pseudocysts. Perforation of a gastrointestinal hollow viscus is rare but has previously been reported. We report a case of a 72-year-old female with the development of three pancreatic pseudocysts four weeks post gallstone pancreatitis. The patient deteriorated and was found to have a duodenal perforation due to compression forces from the underlying pseudocysts. The patient required emergency surgical intervention and recovered fully following hospital admission. [ABSTRACT FROM AUTHOR]

The selective reflection of cholesteric liquid crystals (CLCs) is well-known and has been utilized in a number of dynamic optical applications. This work presents a novel approach to passively (e.g., all-optically) cue reflection notch broadening in photoresponsive CLC formulations based on high helical twisting power (HTP) bis(azo) chiral dopants. The original reflection bandwidth of approximately 100 nm is increased to as much as 1700 nm, by exposing 36 μm thick cells to UV light. The maximum attainable bandwidth is shown to be a function of cell thickness, light intensity, and strongly related to the HTP of the photoresponsive chiral dopants. An all-optical technique of simultaneous UV and green light exposure is demonstrated to trap the reflection notch at a predetermined position and bandwidth. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers (LCEs) are anisotropic polymeric materials. When subjected to an applied stress, liquid crystalline (LC) mesogens within the elastomeric polymer network (re)orient to the loading direction. The (re)orientation during deformation results in nonlinear stress‐strain dependence (referred to as soft elasticity). Here, we uniquely explore mechanotropic phase transitions in elastomers with appreciable mesogenic content and compare these responses to LCEs in the polydomain orientation. The isotropic (amorphous) elastomers undergo significant directional orientation upon loading, evident in strong birefringence and x‐ray diffraction. Functionally, the mechanotropic displacement of the elastomers to load is also nonlinear. However, unlike the analogous polydomain LCE compositions examined here, the isotropic elastomers rapidly recover after deformation. The mechanotropic orientation of the mesogens in these materials increase the toughness of these thiol‐ene photopolymers by nearly 1300 % relative to a chemically similar elastomer prepared from wholly isotropic precursors. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers (LCEs) are anisotropic polymeric materials. When subjected to an applied stress, liquid crystalline (LC) mesogens within the elastomeric polymer network (re)orient to the loading direction. The (re)orientation during deformation results in nonlinear stress‐strain dependence (referred to as soft elasticity). Here, we uniquely explore mechanotropic phase transitions in elastomers with appreciable mesogenic content and compare these responses to LCEs in the polydomain orientation. The isotropic (amorphous) elastomers undergo significant directional orientation upon loading, evident in strong birefringence and x‐ray diffraction. Functionally, the mechanotropic displacement of the elastomers to load is also nonlinear. However, unlike the analogous polydomain LCE compositions examined here, the isotropic elastomers rapidly recover after deformation. The mechanotropic orientation of the mesogens in these materials increase the toughness of these thiol‐ene photopolymers by nearly 1300 % relative to a chemically similar elastomer prepared from wholly isotropic precursors. [ABSTRACT FROM AUTHOR]

Materials that can be switched between low and high thermal conductivity states would advance the control and conversion of thermal energy. Employing in situ time-domain thermoreflectance (TDTR) and in situ synchrotron X-ray scattering, we report a reversible, light-responsive azobenzene polymer that switches between high (0.35 W m-1 K-1) and low thermal conductivity (0.10 W m-1 K-1) states. This threefold change in the thermal conductivity is achieved by modulation of chain alignment resulted from the conformational transition between planar (trans) and nonplanar (cis) azobenzene groups under UV and green light illumination. This conformational transition leads to changes in the π-π stacking geometry and drives the crystal-to-liquid transition, which is fully reversible and occurs on a time scale of tens of seconds at room temperature. This result demonstrates an effective control of the thermophysical properties of polymers by modulating interchain π-π networks by light. [ABSTRACT FROM AUTHOR]

This article explains the changing relationship between Irish leaders, the Irish-American diaspora, Irish-American political elites, and American diplomacy. Specifically, we explore the transnational advocacy networks (TANSs) associated with the Irish diaspora and their impact on American diplomacy. In the early twentieth century, de Valera failed to mobilize Irish-America to convince President Wilson to recognize the Irish Republic. By the late twentieth century Irish-Americans became effective foreign policy entrepreneurs in Congress re-orienting US diplomacy toward Northern Ireland. Irish political elites utilized both the diaspora and their elite connections to transform the American policy of deference to its Cold War ally to an engaged diplomacy mediating and promoting peace. [ABSTRACT FROM AUTHOR]

Utilizing sequential layer-by-layer (LBL) coating and subsequent photopolymerization, we developed circular-polarizing and free-standing mirrors with a broad reflection bandwidth. Photopolymerizable cholesteric liquid crystal (CLC) paints were first prepared by considering the intrinsic chirality and the coating viscoelasticity. The polymer-stabilized nanostructures had finely tuned helical pitches that selectively reflected light over the entire visible wavelength range. The CLC films exhibited excellent thermomechanical properties and chemical stabilities, which enabled the preparation of patterned optical objects at macroscopic dimensions. The LBL coating and photopolymerization of the CLC paints demonstrated here can provide a simple solution for manufacturing flexible photonic devices with large areas at low cost. Helicoidally stacked polymer networks constructed by coating and curing the chirophotonic crystal paints has great potential to fabricate flexible mirrors with macroscopic dimensions and broad bandwidth. An innovative paint containing polymer-stabilized liquid crystals can be turned into bendable and highly reflective mirrors. The brilliant hues found on peacock feathers arise from structural coloration, a phenomenon where tiny microstructures deflect and modify light waves. Kwang-Un Jeong at Chonbuk National University in Jeonbuk, South Korea, and colleagues now report a technique to generate structural colors inside acrylic-based paints. By adding precise amounts of helical liquid crystals to the paint and curing it with ultraviolet light, ordered nanoscale regions appeared that generated either red, green, or blue colors. The paint could be lithographically fabricated into free-standing objects that have exceptional chemical and mechanical stability. Vertically stacking paint coatings with different colors onto a single substrate yielded silvery flexible mirrors that were able to reflect the entire visible light spectrum. [ABSTRACT FROM AUTHOR]

ABSTRACT: Polymerization of crosslinkable liquid crystal monomers in chiral liquid crystalline media stabilizes the phase and enables distinct electro‐optic properties relative to small‐molecule analogs. Particularly interesting are cases where the polymerization forms a crosslinked polymer network that maintains a “structural” chirality. Recent reports have employed this methodology to realize a diverse set of electro‐optic responses in polymer stabilized cholesteric liquid crystals (PSCLCs) including reflection bandwidth broadening, reflection wavelength tuning, and dynamic scattering modes. It has been proposed that the mechanism at the root of these electro‐optic responses is an ion‐mediated, electromechanical deformation of the stabilizing and structurally chiral polymer network. In an effort to better understand the nature of these deformations, here we have characterized the electro‐optic response of PSCLCs with different polymer concentrations and crosslink densities. The dynamic response of PSCLCs to electric fields exhibits a time‐dependent behavior reminiscent of the creep of polymeric materials to mechanical deformations. The electro‐optic response can be described as the superposition of two contributions: the fast deformation of a relatively soft component of the polymer network (1–2 s) and the slower (10–20 s) deformation of a harder component. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1087–1093 [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCEs) are soft, anisotropic materials that exhibit large shape transformations when subjected to various stimuli. Here we demonstrate a facile approach to enhance the out-of-plane work capacity of these materials by an order of magnitude, to nearly 20 J/kg. The enhancement in force output is enabled by the development of a room temperature polymerizable composition used both to prepare individual films, organized via directed self-assembly to retain arrays of topological defect profiles, as well as act as an adhesive to combine the LCE layers. The material actuator is shown to displace a load >2500× heavier than its own weight nearly 0.5 mm. [ABSTRACT FROM AUTHOR]

ABSTRACT: Liquid crystals are widely employed as stimuli‐responsive materials. Liquid crystallinity can be retained in polymeric form. Photoinduced mechanical effects in liquid crystalline polymer networks and elastomers have been a topic of considerable recent research. This review details the historical underpinnings and recent advances in the synthesis and the corresponding photomechanical response of these materials. In nearly all cases, the conversion of light into mechanical work has employed azobenzene as either a guest additive or covalently attached to the network. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 695–705 [ABSTRACT FROM AUTHOR]