Reconfigurable Visible Light-Driven Liquid Crystalline Network Showing Off-Equilibrium Motions Enabled by Mesogen-Grafted Donor-Acceptor Stenhouse Adducts.

Liquid crystalline network (LCN)-based soft actuators have opened up great opportunities to fabricate emerging and intriguing smart materials, serving as potential building blocks for intelligent soft robotics. Endowing LCN actuators with complex responsive behaviors to enhance their intelligence is both challenging and highly demanded. Herein, Donor-Acceptor Stenhouse Adducts (DASAs) molecules with rod-like mesogen and the polymerizable group are judiciously designed and synthesized, which is strong-colored at linear form and de-coloration at cyclic form after visible light. In the colored state, the DASA presents a striking photothermal effect that is capable of driving the motions of LCN film. Upon visible light irradiation, the DASA becomes colorless, making the diminishing photothermal effect. The light-gated switching of the photothermal effect renders the LCN films to be reconfigurable and perform off-equilibrium motions. The varying glass transition temperature of LCN matrix endowing tunable isomerization rates of DASAs and the equilibrium balance of photo- and thermal-isomerization at different temperatures in LCN-P-DASA film mainly guiding the off-equilibrium or stable motions, providing high adjustability of the novel visible light-driven LCN actuators. The multiply modulated LCN-P-DASA film holds great potential in constructing complex visible light-driven soft actuators based on the synergetic effect and interactions of photochemical and photothermal effects.

Dynamically Modulating the Dissymmetry Factor of Circularly Polarized Organic Ultralong Room-Temperature Phosphorescence from Soft Helical Superstructures.

Achieving circularly polarized organic ultralong room-temperature phosphorescence (CP-OURTP) with a high luminescent dissymmetry factor (glum ) is crucial for diverse optoelectronic applications. In particular, dynamically controlling the dissymmetry factor of CP-OURTP can profoundly advance these applications, but it is still unprecedented. This study introduces an effective strategy to achieve photoirradiation-driven chirality regulation in a bilayered structure film, which consists of a layer of soft helical superstructure incorporated with a light-driven molecular motor and a layer of room-temperature phosphorescent (RTP) polymer. The prepared bilayered film exhibits CP-OURTP with an emission lifetime of 805 ms and a glum value up to 1.38. Remarkably, the glum value of the resulting CP-OURTP film can be reversibly controlled between 0.6 and 1.38 over 20 cycles by light irradiation, representing the first example of dynamically controlling the glum in CP-OURTP.

High-Performance Organic Narrow Dual-Band Circular Polarized Light Detection for Encrypted Communications and Color Imaging.

Conventional circularly polarized light (CPL) detectors necessitate several optical elements, posing difficulties in achieving miniature and integrated devices. Recently developed organic CPL detectors require no additional optical elements but usually suffer from low detectivity or low asymmetry factor (g-factor). Here, an organic CPL detector with excellent detectivity and a high g-factor is fabricated. By employing an inverted quasi-planar heterojunction (IPHJ) structure and incorporating an additional liquid crystal film, a CPL detector with an outstanding g-factor of 1.62 is developed. Unfavorable charge injection is effectively suppressed by the IPHJ structure, which reduces the dark current of the organic photodetector. Consequently, a left CPL detectivity of 6.16 × 1014 Jones at 640 nm is realized, surpassing all of the latest photodiode-type CPL detectors. Adopting a liquid crystal film with adjustable wavelengths of selectively reflected light, the hybrid device achieves narrow dual-band CPL detection, varying from 530 to 640 nm, with a half-maximum full width below 90 nm. Notably, the device achieves excellent stability of 260 000 on/off cycles without attenuation. To the best of the authors' knowledge, all these features have rarely been reported in previous work. The CPL detector arrays are also demonstrated for encrypted communications and color imaging.

Shape-Programmable Liquid-Crystalline Polyurethane-Based Multimode Actuators Triggered by Light-Driven Molecular Motors.

In recent years, light-driven soft actuators have been rapidly developed as enablers in the fabrication of artificial robots and biomimetic devices. However, it remains challenging to amplify molecular isomerization to multiple modes of macroscopic actuation with large amplitude and complex motions. Here, a strategy is reported to build a light-responsive liquid-crystalline polyurethane elastomer by phototriggered overcrowded alkene-based molecular motors. A trifunctional molecular motor modified with an ethylene glycol spacer on the rotor and stator functions as a crosslinker and unidirectional stirrer that amplifies molecular motion into macroscopic movement. The shape-programmable polymeric film presents superior mechanical properties and characteristic shape-memory effect. Furthermore, diverse modes of motions including bending, unwinding, and contracting with tunable actuation speed over a wide range are achieved. Such research is hoped to pave a new way for the design of advanced light-responsive soft actuators and robots.

Graphene/Cholesteric Liquid-Crystal-Based Electro-Driven Thermochromic Light Modulators toward Wide-Gamut Dynamic Light Color-Tuning-Related Applications.

Light filters are ubiquitous in projection and display techniques, illumination engineering, image sensing, photography, etc., while those enabling wide-gamut dynamic light color tuning are still lacking. Herein, by combining the electro-heating capability of graphene and unique optical properties (thermochromism and circular dichroism) of small-molecule-weight cholesteric liquid crystal (ChLC), a brand-new thermochromic light modulator is constructed as actively tunable color filter. Transparent graphene/glass hybrid with reasonably high conductivity serves both as a high-performance heater for actuating the thermochromism of temperature-responsive ChLC and as neutral light attenuator for brightness control. Thanks to the temperature- and polarization-dependent spectral properties of the ChLC, widely tunable hue and saturation properties of transmission light color are achieved, respectively. Several intriguing applications, e.g., color-variable smart windows for backlight color tuning and color-variable filters for photography, are also demonstrated. This work hereby provides new paradigms for promoting the applications of graphene/ChLC-based light modulators in next-generation light-management-related scenarios.

Orthogonally Integrating Programmable Structural Color and Photo-Rewritable Fluorescence in Hydrazone Photoswitch-bonded Cholesteric Liquid Crystalline Network.

Design and fabrication of advanced security label showing superior performance in data encryption has attracted tremendous scientific interests. Especially, multifunctional optical labels capable of storing distinct information in different modes are highly demanded. Here, a fluorescent cholesteric liquid crystalline network (CLCN) film with programmable visible patterns and photo-rewritable fluorescent patterns was designed and prepared. The visible patterns were fixed by helical network and the colors of visible patterns were tunable by changing relative humidity (RH). The fluorescent patterns originated from dynamic isomerization of fluorescent hydrazones, exhibiting highly thermal stability and switching-ability controlled by light. The orthogonal construction of visible and fluorescent pattern enabled the novel CLCN to encrypt distinct information in reflective mode and in emissive mode, indicating its potential in anti-counterfeiting and information encryptions.

Impact of MDR1 and UGT Gene Polymorphisms on Sodium Valproate Plasma Concentration in Patients with Epilepsy.

BACKGROUND: This study aimed to identify the effects of multidrug resistance gene 1 (MDR1) and UGT gene polymorphisms on the plasma concentration of VPA in subjects with epilepsy and provide a reference for individualized medicine of patients with epilepsy. METHODS: One hundred subjects with epilepsy who were treated with sustained release VPA monotherapy were enrolled. Sanger sequencing was used to detect the genotypes of MDR1_G1199A, MDR1_G2677T/A, UGT1A6_A 552C, T19G and UGT2B7_C161T. By adjusting the plasma concentrations of VPA with body weight and a total daily dose of VPA, the concentration-to-dose ratio of VPA (CDRV) was obtained. Data were analyzed using SPSS17.0. RESULTS: No mutation of MDR1_G1199A gene was detected. MDR1_G2677T/A site T allele frequency is 43.5%, A is 14%. The genetic frequencies of UGT1A6_A552C, T19G, and UGT2B7_C161T were 29.5%, 25.5%, and 36%, respectively. Significant differences in CDRV were observed between carriers of TT, TG, and GG genotypes in the UGT1A6_T19G polymorphism (p = 0.021, p < 0.05). The CDRV was significantly lower in patients carry UGT1A6_T19G GG genotype compared to TG ((3.40 ± 1.61) µg.kg/mL.mg) and TT ((4.33 ± 1.97) µg.kg/mL.mg) genotype. While the MDR1_G2677T/A, UGT1A6_A552C and UGT2B7_C161T gene polymorphisms had no effect on the plasma concentration of VPA (p > 0.05). CONCLUSIONS: The genetic polymorphisms of UGT1A6_T19G significantly affect the plasma concentration of VPA in patients with epilepsy and the mutation of this locus can decrease the blood concentration of VPA. The MDR1_G2677T/A, UGT1A6_A552C and UGT2B7_C161T gene polymorphisms did not affect the plasma VPA concentration in Han patients with epilepsy.

Amplifying Molecular Scale Rotary Motion: The Marriage of Overcrowded Alkene Molecular Motor with Liquid Crystals.

Design and fabrication of macroscopic functional devices by molecular engineering is an emerging and effective strategy in exploration of advanced materials. Photoresponsive overcrowded alkene-based molecular motor (OAMM) is considered as one of the most promising molecular machines due to the unique rotary motion driven by light with high temporal and spatial precision. Amplifying the molecular rotary motions into macroscopic behaviors of photodirected systems links the molecular dynamics with macroscopic motions of materials, providing new opportunities to design novel materials and devices with a bottom-up strategy. In this review, recent developments of the light-responsive liquid crystal system triggered by OAMM will be summarized. The mechanism of amplification effect of liquid crystal matrix will be introduced first. Then progress of the OAMM-driven liquid crystal materials will be described including light-controlled photonic crystals, texture-tunable liquid crystal coating and microspheres, photoactuated soft robots, and dynamic optical devices. It is hoped that this review provides inspirations in design and exploration of light-driven soft matters and novel functional materials from molecular engineering to structural modification.

Freestanding Helical Nanostructured Chiro-Photonic Crystal Film and Anticounterfeiting Label Enabled by a Cholesterol-Grafted Light-Driven Molecular Motor.

Design and fabrication of freestanding chiro-photonic crystal film with the ability to change color over the whole visible light spectrum is appealing for anticounterfeiting technology and smart labels. Utilizing a newly synthesized light-responsive molecular motor functionalized with cholesterol (chol-MM) on the rotor, novel light-controlled photonic crystal is prepared by doping the novel chol-MM into liquid crystals (LCs). Thanks to the liquid crystalline cholesterol substituent, the chol-MM can be triggered by visible light (420 nm). At the same time, the miscibility of chol-MM in LC matrix is significantly enhanced. Integrating the chol-MM with thermochromic hydrogen-bonded LC matrix, thermal and light dual-responsive cholesteric LC (CLC) material is prepared, in which the nanoscale helical pitch is tunable by photo-induced molecular motions of chol-MM. More importantly, utilizing UV-initiated polymerization of the visible light-modulated CLC material, structural colored photonic crystal films with arbitrary colorful patterns are fabricated. Such freestanding helical nanostructured labels have potential in the application of encrypted communication and anticounterfeiting.

Reprogrammable Humidity-Driven Liquid Crystalline Polymer Actuator Enabled by Dynamic Ionic Bonds.

Liquid crystalline polymer (LCP) is a promising candidate in the design and fabrication of intelligent soft materials due to the combination of programmable anisotropy and elasticity. Here, a novel strategy to fabricate reprogrammable humidity-responsive LCP materials enabled by dynamic ionic cross-links were put forward. The prepared LCP film deforms reversibly with the change of relative humidity (RH). However, the humidity responsivity loses after soaking the film into CaCl2 solution because of the lock of hygroscopic groups by the formed ionic bonds. By selectively cross-linking specific regions of the LCP film, distinctive humidity-driven motions of the film could be realized. More interestingly, by the EDTA-2K solution treatment, ionic cross-links can be interrupted, leading the LCP film responsive to humidity again. Thanks to feasibly removable ionic cross-links, the humidity-directed soft actuator was totally reprogrammable. The behavior of the novel actuator could be manipulated by either the mesogens alignment or the spatially ionic treatment, providing a feasible but robust strategy to fabricate complex humidity-driven soft robots.

Humidity-Responsive Photonic Crystals with pH and SO2 Gas Detection Ability Based on Cholesteric Liquid Crystalline Networks.

Dynamic photonic crystals with tunable structural colors have been a hot topic in the research of anticounterfeiting devices, decoration, and detection. In this work, we prepared cholesteric liquid crystalline network (CLCN)-based photonic crystals that present humidity- and SO2 gas-responsive behaviors. The covalently cross-linked CLCN film presents humidity-responsive color changes due to the swelling/deswelling of the matrix under different humidity conditions. When treating the CLCN film with SO2 gas, the carboxylic salt converted to the acid and the film was not able to respond to the humidity change anymore. The mechanism of the SO2 gas-gated humidity responsiveness of the CLCN film was characterized. It was found that the acidic gas caused changes of pH, resulting in the conversion of the salt to acid and alteration of the surface property. The influence of concentration of SO2 gas and pH on humidity responsiveness of the CLCN film was investigated. We hope that this method provides inspirations for the design and fabrication of visualized pH and acidic gas detectors.

Tunable Circularly Polarized Luminescence with a High Dissymmetry Factor Emitted from Luminogen-Bonded and Electrically Controlled Polymer-Stabilized Cholesteric Liquid Crystals.

Circularly polarized luminescence (CPL)-active materials with high dissymmetry factor (glum) values show great potential in photonic devices. In this study, electric-field-driven systems with tunable CPL signals are successfully fabricated based on polymer-stabilized cholesteric liquid crystal (PSChLC) doping by fluorescent molecules. By constructing a gradient helical superstructure of PSChLCs, distinctive CPL emission from two sides of a single sample is realized, in which the |glum| values were measured to be 0.6 and 1.5, respectively. Herein, we discussed the possible mechanism of this phenomenon. In addition, an applied electric field could broaden the reflection bandwidth of PSChLCs from 150 to 500 nm, covering the whole visible light region. Furthermore, this electric field-induced behavior leads to the variation of CPL signals and corresponding glum values, indicating the potential of the novel materials in the design and preparation of CPL-emitting devices with electrically tunable CPL intensity and glum.

Remotely Controlling Drug Release by Light-Responsive Cholesteric Liquid Crystal Microcapsules Triggered by Molecular Motors.

Stimuli-responsive smart nanocarriers are an emerging class of materials applicable in fields including drug delivery and tissue engineering. Instead of constructing responsive polymer shells to control the release and delivery of drugs, in this work, we put forward a novel strategy to endow the internal drugs with light responsivity. The microcapsule consisted of molecular motor (MM)-doped cholesteric liquid crystals (CLCs) and drugs. The drug in gelatin-gum arabic microcapsules can protect the carried drugs for a long time with a low release speed totally resulting from drug diffusion. Under UV light, the MM isomerizes and the chirality changes, inducing the alteration of the superstructure of the CLCs. In this process, the cooperative molecular disturbance accelerates the diffusion of the drugs from the microcapsule core to the outside. As a result, thanks to the cooperative effect of liquid crystalline mesogens, molecular-scale geometric changes of motors could be amplified to the microscale disturbance of the self-organized superstructure of the CLCs, resulting in the acceleration of the drug release. This method is hoped to provide opportunities in the design and fabrication of novel functional drug delivery systems.

Photochemically and Photothermally Controllable Liquid Crystalline Network and Soft Walkers.

Developing intelligent soft robots capable to perform various responses to different stimulations has been a hot topic in recent years. Liquid crystalline networks (LCNs) have been considered as one of the most promising candidates in the fabrication of soft actuators because of the combination of elasticity of the polymer and anisotropy of the liquid crystals. However, the design and fabrication of advanced LCN materials with outstanding performances and multiple responsivities is highly demanded but still a challenge. In this work, a NIR-UV dual light-responsive LCN actuator was prepared by selectively coating a polydopamine (PDA) layer on an azobenzene-doped LCN film. This actuator presents UV responsivity in the uncoated region because of the photochemical isomerization of azobenzene and NIR sensitivity in the PDA-coated region originated from the striking photothermal effect. Thanks to the reprogrammable PDA coating, this dual-responsive LCN actuator was totally reprogrammable by coating and washing the PDA layer repeatedly. Based on the novel soft actuator, an artificial car that can imitate the switch of the "forward gear" to "neutral gear" of a real car was prepared. In normal mode, the actuator can move forward under NIR irradiation. After UV light excitation, the actuator cannot move under the same NIR irradiation, just like the car with the level in neutral. This novel actuator may provide inspirations for the fabrication of light-driven functional devices and soft actuators.