Intelligent soft robots that integrate both structural color and controllable actuation ability have attracted substantial attention for constructing biomimetic systems, biomedical devices, and soft robotics. However, simultaneously endowing single-layer cholesteric liquid crystal elastomer (CLCE) soft actuators with reversible 3D deformability and vivid structural color changes is still challenging. Herein, a multi-responsive (force, heat and light) single-layer 3D deformable soft actuator with vivid structural color-changing ability is realized through the reduced graphene oxide (RGO) deposition-induced Janus structure of the CLCE using a precisely-controlled evaporation method.
View Article and Find Full Text PDFThe polymer dispersed liquid crystal (PDLC) holds potential application in smart windows, owing to its feasibility in regulating the transmittance of specific wavelength bands to improve energy utilization. Herein, a composite PDLC smart window is designed, which showcases high emissivity of 93.79% in the mid-infrared region and features the regulation of ultraviolet (UV), visible, and near-infrared (NIR) light.
View Article and Find Full Text PDFPolymer-stabilized liquid crystals (PSLCs) are widely used in smart windows, light modulators, and dimmed glass. However, their low mechanical strength, unsatisfactory electro-optical properties, and poor durability limit their large-scale application. In this study, a PSLC film with outstanding performance is prepared by incorporating a multifunctional molecule into a fine-sculptured liquid crystal/polymer composite.
View Article and Find Full Text PDFA series of polymer-dispersed liquid crystal (PDLC) films were prepared by using acrylate monomers containing heteroatom-terminated groups. The microscopic morphology and electro-optical properties reveal that these monomers effectively reduce the switching voltage and improve the contrast ratio at the same time. The saturation voltage of the best sample was reduced by 47%, and the contrast ratio was improved by 74%.
View Article and Find Full Text PDFStepwise photopolymerization is a miraculous strategy modulating the polymer skeleton and electro-optical properties of light modulators based on liquid crystal/polymer composites. However, owing to the indistinct polymerization mechanism and curing condition discrepancy, the required polymer structures and electro-optical properties are hard to be controlled precisely. Herein, a novel polymer-stabilized liquid crystal film based on acrylate/epoxy resin is proposed, fabricated and the relationships between preparation process, polymer content, polymer morphology and electro-optical properties are studied.
View Article and Find Full Text PDFPolymer-stabilized liquid crystal (PSLC) is a promising material toward the practical application of serving as energy-saving reverse-mode smart windows owing to its superior electro-optical (E-O) properties, simple and efficient processability, and compatibility to most practical circumstances. However, its feeble peel strength originated from low polymer content and poor adhesion between polymer networks and substrates inhibited its large-scale flexible film production. It is still a challenging task to derive good mechanical properties and superior E-O performance for PSLCs at the same time.
View Article and Find Full Text PDFSmart windows with synergetic light modulation have heightened demands for applications in smart cars and novel buildings. However, improving the on-demand energy-saving efficiency is quite challenging due to the difficulty of modulating sunlight with a broad bandwidth in an energy-saving way. Herein, a smart window with switchable near-infrared light transmittance and passive radiative cooling is prepared via a monomer design strategy and photoinduced polymerization.
View Article and Find Full Text PDFAs a type of intelligent dimming film, polymer-dispersed liquid crystals (PDLCs) have been widely applied in various fields, such as smart windows, light shutters and displays. The properties of PDLCs are greatly influenced by the structure of the raw materials. In this work, the impact of crosslinking agents with different cyclic or chain groups was investigated by comparing the electro-optical performance and the morphology of the polymer matrix in the as-made PDLC films.
View Article and Find Full Text PDFObjective: To analyse the short-term clinical results of the effect of apically repositioned flap combined with free gingival graft to widen keratinized tissue in implant area, so as to provide a basis for its clinical application.
Methods: Fifteen patients with intraoral single or multiple missing teeth, who did not undergo implant restoration or who re-examined after implant restoration completed were included, along with KW less than 1-2 mm on the buccal side of the median line of the alveolar ridge crest in the implant area, or KW less than 1-2 mm on the buccal side of the abutments and dental crown margins. All underwent apically repositioned flap combined with free gingival graft, which were reviewed.
Polymer-dispersed liquid crystals (PDLCs) show great application potential in the areas of displays and smart windows. However, their electro-optical (E-O) properties such as contrast ratio and threshold voltage still need further improvement. In this study, the effects of α-substituted acrylate monomers on the morphology and E-O properties of PDLC composite films were systematically studied.
View Article and Find Full Text PDFAs a type of smart dimming film, polymer-dispersed liquid crystals (PDLCs) show great prospects in the fields of indoor partition, electronic curtains, and automobile windows. However, its high off-axis haze greatly impacts the application scope. This obvious shortcoming is mainly caused by the serious mismatch between the effective refractive index of the liquid crystal () and the refractive index of the polymer matrix () at large viewing angles.
View Article and Find Full Text PDFWith the switchability between transparent and light-scattering states, polymer-dispersed liquid crystals (PDLC) are widely used as smart windows, flexible display devices, projectors, and other devices. In outdoor applications, in addition to excellent electro-optical properties, there is also a high demand for film stability. In this work, a PDLC film with high mechanical strength and structural stability is prepared that can maintain stability at 80 °C for 2000 h.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2022
Light-emitting diodes (LEDs) based on all-inorganic lead halide perovskite quantum dots (PQDs) have undergone rapid development especially in the past five years, and external quantum efficiencies (EQEs) of the corresponding green- and red-emitting devices have exceeded 23%. However, the blue-emitting devices are facing greater challenges than their counterparts, and their poor luminous efficiency has hindered the display application of PQD-based LEDs (PeQLEDs). This review focuses on the key challenges of blue-emitting PeQLEDs including low EQEs, short operating lifetime, and spectral instability, and discusses the essential mechanism by referring to the latest research.
View Article and Find Full Text PDFCellular senescence refers to the permanent arrest of cell cycle caused by intrinsic and/or extrinsic stressors including oncogene activation, irradiation, DNA damage, oxidative stress, and certain cytokines (including senescence associated secretory phenotype). Cellular senescence is an important factor in aging. Accumulation of senescent cells has been implicated in the causation of various age-related organ disorders, tissue dysfunction, and chronic diseases.
View Article and Find Full Text PDFElectron transport layers (ETLs) play a key role in the electron transport properties and photovoltaic performance of solar cells. Although the existing ETLs such as TiO, ZnO and SnO have been widely used to fabricate high performance solar cells, they still suffer from several inherent drawbacks such as low electron mobility and poor chemical stability. Therefore, exploring other novel and effective electron transport materials is of great importance.
View Article and Find Full Text PDFBiaxiality and chirality are two of the most interesting topics in materials and biological science, particularly in liquid crystals. What is even more interesting is that these two properties are related. It was theoretically predicted that morphological chirality is impossible without morphological biaxiality in chiral nematic liquid crystals.
View Article and Find Full Text PDFWhen subjected to an AC electric field perpendicular to its layers, the cholesteric planar state may undergo a periodic layer undulation, known as the Helfrich deformation, which generates a color change of the reflected light. The Helfrich deformation of regular cholesteric liquid crystals is, however, unstable and easily taken over by the focal conic state, and thus the color tuning range is narrow. We demonstrated that the Helfrich deformation can be stabilized in a large electric field region by doping a bent dimer with an anomalously small bend elastic constant and dispersing a small amount of polymer network.
View Article and Find Full Text PDFMacromol Rapid Commun
August 2017
Controlling self-assembly behaviors of liquid crystals is a fundamental issue for designing them as intelligent actuators. Here, anisotropic porous polyvinylidene fluoride film is utilized as a template to induce homogeneous alignment of liquid crystals. The mechanism of liquid crystal alignment induced by anisotropic porous polyvinylidene fluoride film is illustrated based on the relationship between the alignment behavior of liquid crystals and surface microstructure of anisotropic polyvinylidene fluoride film.
View Article and Find Full Text PDFChiral nematic liquid crystals possess a self-assembled helical structure and exhibit unique selective reflection in visible and infrared light regions. Their optical properties can be electrically tuned. The tuning involves the unwinding and restoring of the helical structure.
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