Window Applications Research Articles

Progress and Prospect of Liquid Crystal Droplets

Liquid crystal (LC) droplets are highly attractive for applications in privacy windows, optical switches, optical vortices, optical microresonators, microlenses, and biosensors due to their ease of fabrication and easy alignment at surfaces. This review presents the latest advancements in LC droplets, which have nematic, chiral nematic, and twist–bend nematic and ferroelectric nematic phases, or blue phases. Finally, it discusses the challenges and opportunities for applications based on LC droplets. The main challenges encompass the precise control of internal structures and defects to meet diverse application requirements, enhancing stability and durability across various environments, reducing large-scale production costs to improve commercial feasibility, increasing response speeds to external stimuli to adapt to rapidly changing scenarios, and developing tunable LC droplets to achieve broader functionalities.

A Multimode Dynamic Color-Changing Device for Smart Windows Based on Integrating Thermochromic and Electrochromic Properties.

Electro- and thermochromic materials have been greatly applied in smart windows and displays due to the excellent properties of color variation and solar radiation. However, the mono color and single response to voltage and temperature hinder their application and development. Here, a multimode dynamic color-changing device (T/ECD) was developed by integrating the electrochromic property of synthetic viologen dyes and the thermochromic properties of hydroxypropyl acrylate (HPA). The T/ECD achieves four modes of optical regulation, namely, colorless transparent state, tinted transparent state, colorless opaque state, and tinted opaque state, which can be regulated independently/coordinately using heat and voltage. The optimized T/ECD switched color at 1.2 V with 15 s or adjusted the transparent/opaque state at >34 °C with 46 s. In addition, based on the red viologen (ViO-R), green viologen (ViO-G), and blue viologen (ViO-B) dyes, colorful T/ECDs were successfully designed and fabricated, and T/ECDs have excellent cycling properties, expanding the application requirement. Moreover, we demonstrated their application in smart windows and privacy protection. The design philosophy and successful exploration have great prospects for energy-saving buildings, displays, and information masking/storage systems.

Review of Angular-Selective Windows with Guest–Host Liquid Crystals for Static Window Applications

This review focuses on the development and advancements in angular-selective smart windows, with particular emphasis on static windows utilizing guest–host liquid crystal (GHLC) systems. Angular-selective windows are designed to adjust their transmittance based on the angle of incident light, offering enhanced energy efficiency and visual comfort in both architectural and automotive applications. By leveraging the anisotropic absorption properties of dichroic dyes, GHLC-based windows can selectively block oblique sunlight while preserving clear visibility from normal viewing angles. Various liquid crystal (LC) alignment configurations, including vertically aligned, homogeneously aligned, hybrid aligned, uniformly lying helix, and twisted aligned LC cells, have been investigated to optimize light control for different installation angles, such as for automotive windshields and building windows. These advancements have demonstrated significant improvements in energy conservation and occupant comfort by reducing cooling demands and regulating sunlight penetration. This review summarizes key findings from recent studies, addresses the limitations of current technologies, and outlines potential future directions for further advancements in smart window technology.

Fabrication of Zinc(II) Mediated Poly(Acrylamide Co Acrylic Acid) Hydrogel with Thixotropic and Tribological Properties.

Hydrogels have emerged as promising candidates for biomedical applications, such as replacing natural articular cartilage, owing to their unique viscoelastic properties. However, sufficient mechanical properties, self-healing ability, and adhesive nature are some issues limiting its application window. Here, a facile one-pot synthesis of dual cross-linked zinc-coordinated copolymer hydrogels is presented. The network structure of the copolymer hydrogels is strategically developed via dynamic and reversible physical cross-linking by Zn2+ ions and simultaneous covalent cross-linking through a covalent cross-linker viz methylene bisacrylamide. Fourier-transform infrared (FTIR), X-ray diffraction (XRD) scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis have thoroughly characterized the structure of the synthesized hydrogels. The introduction of Zn2+ offers dynamic and reversible complexation, leading to excellent mechanical properties and self-healing features. Moreover, the percentage of the equilibrium water content of zinc-coordinated copolymer hydrogel samples is comparable with that of natural articular cartilage. The Shear sliding study shows the dominant adhesive behavior of HGel-Zn(NO3)2 sample compared to the parent HGel sample. This facile dual cross-linked hydrogel, HGel-Zn(NO3)2, with a combination of good mechanical properties, efficient self-recovery, adequate water content, and favorable adhesive nature, seems very promising to mimic the articular cartilage.

Facile fabrication of hemicrystalline bio-based polycarbonate with superhydrophobic and high transmittance

Developing materials that combine superhydrophobic properties with high optical transmittance poses a significant challenge. In this study, hydroxyl-terminated polydimethylsiloxane (HT-PDMS) and isosorbide (ISB) were polymerized in a single step to create a covalently bonded optical polycarbonate material. By inducing the formation of micro-papillary and lotus-shaped nanoscale structures via a solvent-triggered process, we significantly enhanced the “air cushion” effect, achieving a structure scale of approximately 5–7 μm. This resulted in a water contact angle of 157° while maintaining over 90 % optical transmittance. The structures were uniformly distributed throughout the polymer matrix, leading to a 500 % increase in tensile strength at break compared to pure isosorbide polycarbonate, with a maximum strength exceeding 50 MPa. These multifunctional materials show great promise for applications in smart windows, solar panels, camera lenses, and other optoelectronic devices.

Molecular Confinement Engineering Induced Super Thermostable and RT‐Adjustable Gel for Tri‐Heat‐Channeled Smart Window

AbstractThermochromic hydrogel‐based smart windows hold great potential for building energy‐saving. However, most of thermochromic hydrogels possess high response temperatures (RT) and poor size stability under heat, resulting in limited energy‐saving performance for smart windows. Here, a printable thermochromic gel (PNC) is reported with low thermal shrinkage and tunable RT for smart windows applications via molecular confinement engineering. The RT of PNC gel is well within the comfort temperature zone of the human body and can be modulated (26.5–31.5 °C) by the introduced support networks. Importantly, the resultant gel exhibits a super transmittance (95%) in visible light and an outstanding modulation (87%) for sunlight. Based on PNC gel, a tri‐heat‐channeled smart window is fabricated using a multilevel thermal regulation strategy that couples conduction, radiation, and evaporative cooling. The tri‐heat‐channeled smart window demonstrates outstanding daytime cooling (10 °C lower than conventional windows) and can cut off 30% of annual heating, ventilation, and air‐conditioning (HAVC) energy consumption. Furthermore, a novel smart window is designed with invisible shutters that appear only when needed. This work offers novel clues for constructing versatile gels and innovative smart windows for building energy‐saving.

Creating window applications in Python using the PyQt5 library tools

The section "Programming" at the advanced level of studying the informatics course in high school includes consideration of issues related to the design of the user interface. If the study of the basics of programming is carried out using the Python language, it is reasonable to develop window applications using this language. Recently, the PyQt library has become increasingly popular, which makes it relevant to create methodological materials to familiarize schoolchildren with the capabilities of this library.It is advisable to carry out training in accordance with the reverse engineering technology, which consists in the fact that students do not write program code from scratch, but explore the finished product. At the first stage, you can organize the activities of schoolchildren by completing tasks to study the finished program; at the next step, offer to analyze the appearance of the finished application, highlight its elements and select tools for their creation; finally, provide additional tasks that involve independent study by students of the class features not considered earlier.The article offers reference material for familiarizing schoolchildren with the main capabilities of the library, tasks for lab sessions and home assignment.

Development of hydrophilic multilayer structures for energy saving window applications using sol-gel spin coating

This study is centered on analyzing the microstructural and optical reflectivity properties of multilayers composed of dielectric titania and silica. The goal is to investigate their potential application as energy-efficient windows on glass surfaces in different modern building projects. Nevertheless, the creation of these coatings can be quite expensive due to their complex structure. This study focuses on the development of a cost-effective method to produce a multilayer structure made of titania and silica. This structure has the remarkable ability to reflect approximately 100 % of UV light and 70 % of infrared light, all achieved with just three layers. The X-ray diffraction (XRD) analysis was conducted to examine the crystallinity of the coatings. The results indicated the presence of an anatase phase, as evidenced by the Bragg angle of 25O. Empirical support was obtained through the use of Fourier transform infrared spectroscopy (FTIR), which revealed the presence of functional bonds at specific wavenumbers. Titania and silica were identified at wave numbers of 596 cm−1 and 1246 cm−1, respectively. The FTIR investigation was further supported by energy dispersive spectrum analysis (EDAX), which verified the existence of titania and silica in the multilayer structure. Through the use of field emission scanning electron microscopy (FESEM), the analysis of the multilayer structure unveiled the existence of layers composed of titania, silica, and titania. These layers were found to have thicknesses of approximately 286 nm, 315 nm, and 222 nm, respectively. The coatings were analyzed for reflectance using a UV–VIS-NIR spectrophotometer, which showed a full reflection of 100 % in the far ultraviolet range and a reflection of 70 % in the infrared region. Furthermore, the analysis of the coatings’ wetting behavior with a contact angle meter revealed their hydrophilic nature, suggesting their potential use in self-cleaning applications.

Mass-Producible Transparent Flexible Passive-Cooling Film.

Passive cooling is regarded as the desired method for interior temperature regulation due to its advantage of energy consumption reduction. An ideal passive-cooling window is expected to exhibit a high emissivity in the mid-infrared (MIR, 8-13 μm) spectral range for cooling and a low transmittance in the near-infrared (NIR, 780-2100 nm) spectral range for reducing heat flow, while presenting a high transmittance in the visible (VIS, 400-780 nm) spectral range for daylighting. However, material structures that meet these requirements often come with high demands for precision in manufacturing and elevated processing costs, which have limited their potential for large-scale mass production. Here, we propose a mass-producible transparent flexible passive-cooling film that is relatively easy to process and low-cost and meets all of the requirements mentioned above. The film is made of poly(methyl methacrylate) mixed with Cs0.33WO3 nanoparticles, and it shows a high absorptance (80%) in NIR for blocking solar radiation penetration and a high emissivity (93%) in MIR for radiative cooling as well as a reasonable transmittance (40%) in VIS for visibility. Under solar intensity of ∼900 W/m2, a maximum temperature reduction of 8.4 and 7.8 °C has been achieved for a window coated by the film compared to the uncoated window in the condition of the absorbing chamber and car, respectively. Such a mass-producible transparent flexible passive-cooling film holds promising applications in large windows, such as those used in automobiles and buildings, where there is a high demand for both daylighting and cooling.

Investigation on enhancement of noise reduction of partially open windows and balconies through mock-up test

Application of Acoustic Windows and Acoustic Balconies is a recent trend in Hong Kong to mitigate road traffic noise impact. In severe situations, enhancement is needed for the mitigation measures to provide additional improvement in acoustic performance. The performances of several common enhancements including micro-perforated absorber panels, perforated absorption panels, and balcony sidewalls are investigated through 1:1 mock-up test. The mock-up test aimed to mimic the actual situation, by referencing the spatial relationship between line sources and receivers. International standards are followed in the mock-up test, including ISO 16283-3: 2016 for microphone setting-out and BS EN 1793-3 for normalized traffic noise spectrum. Based on the mock-up test results, the research revealed that the enhancements' performance changes with line source orientation and suggested the optimum usage of enhancements.

The Influence of Sharia Banking Advertising and Promotion on SMKN 8 Garut Teachers' Interest in Choosing Sharia Banks

This research aims to find out whether advertising and sales promotion variables influence the interest in saving SMKN 8 Garut teachers at Sharia Banks. This research uses quantitative methods and is associative. Data analysis using multiple linear regression with the SPSS 21 for windows application. Meanwhile, data collection uses questionnaires (questionnaires). The sampling technique in this study used purposive sampling techniques. The population in this study were teachers at SMKN 8 Garut. The results of this research show that the t test of advertising variables has a positive and significant effect on teachers' interest in saving with a t count value of 4.311> 1.97 t table, which means that t count > t table. The t test on the sales promotion variable had a positive and significant effect on the teacher's saving interest with a calculated t score of 9,629 > 1.97 t table, which means that t calculated > t table. And for the f test, f count was obtained at 120,708 and f table 3.04, f count > f table which means that the variables advertising and sales promotion together have a positive and significant effect on teachers' interest in saving at Sharia Banks. Meanwhile, the determination coefficient (R2) is 0.531, which means that the contribution of advertising and sales promotion variables is only able to explain the Teacher savings interest variable of 53.1%. Meanwhile, the remaining 46.9% was explained by other variables.

Thermal performance of thermochromic smart windows in different indoor environments

Thermochromic (TC) smart windows can passively respond to the exterior and interior temperature, which further adjust their indoor thermal environments due to the varied photo-thermal parameters. This study investigated the thermal performances of practical TC windows in a room with/without air-conditioning or with stratified temperature distribution through a validated 3D CFD model. The application of TC windows could decrease the window, indoor ambient and floor temperatures, and also improve their temperature uniformity. The upper interior window could be 3.13 °C higher than the bottom in a room without air-conditioning, which could be reduced to 2.48 °C if the TC window was utilized. The uniformity improvement could be more significant for indoor environments with apparent air temperature differences, especially for the air-conditioning case. It is suggested that the indoor air temperature and its uniformity may affect the temperature and uniformity of the TC window surface in turn, specifically its phase transition time.

Fabrication of novel MoOx / PVA hydrogel nanocomposite for photochromic smart window

Photochromic smart windows allow for simple manufacturing without the need for additional energy input for adaptive control of sunlight, which will have a huge impact on the comfort of daylight and the development of smart windows. Among them, although molybdenum-based materials have advantages such as low cost and stable coloring, the lack of fast transmission switching capability and liquid phase color changing environment limit its implementation in the field of smart windows. Here, we report a low-cost method to fabricate a novel photochromic hydrogel (MoOx/PVA) by combining molybdenum oxide nanosheets (MoOx, 2≤x≤3) with polyvinyl alcohol (PVA) gel. Under ultraviolet light (UV=360∼400 nm) irradiation, the hydrogel achieves rapid color change visible to the naked eye within 10 s, with an exponential decrease in transmittance, reversible switching of transparency between 70% and 5%, and retains about 95% transmittance after 14 cycles. Due to the good biocompatibility of molybdenum oxide, hydrogel can also be used for personal wearable, which can achieve 1.4°C of cooling when exposed to sunlight for 3 min. Moreover, the photochromic and recovery properties of the large-sized (29.7 cm×21 cm) MoOx/PVA hydrogel demonstrate its broad prospects for production applications in smart windows. It is believed that this study will open new opportunities for both fabrication and application in photochromic smart windows and intelligent devices.

Nanostructure-dependent colouration efficiency of electrochromic coatings using 0D, 1D, and 2D WO3 for smart windows

Towards the development of highly efficient electrochromic coatings, the crystallinity, morphology (e.g. size and shape) of electrochromic nanomaterials, and their charge insertion capacities play a significant role. Herein, we report the structure-dependent colouration effciency in electrochromic coatings based on the use of 0D, 1D and 2D tungsten trioxide (WO3) nanostructures. A series of WO3 with different nanostructures were prepared and used as working electrodes to fabricate electrochromic devices for smart windows applications. Facile spray coating was applied on fluorine-doped tin oxide (FTO) substrate to make ∼70 ​% transparent working electrodes to investigate their charge insertion capacities, electrochromic active surface area, and colouration efficiency. Results showed that the 2D WO3 nanoflakes displayed the highest diffusion coefficient for the intercalation of 1.52 ​× ​10 −10 ​cm2/s with an increased electrochemical active surface area of 25.10 ​mF/cm2, a large modulation of optical reflectance (42.63 ​%) with 3.79 ​s shorter response time for bleaching and a greater colouration efficiency (CE) value (89.29 ​cm2/C) at 700 ​nm compared to the CE value for 1D WO3 (of 22 ​cm2/C) and 0D WO3 (8 ​cm2/C). The outcome of this study provides a new insight and valuable contribution to design an efficient electrochromic coating by controlling and optimising the nanostructures of selective electrochromic materials.

Epoxy resin-based polymer-wall stabilized liquid crystal films with low driving voltages and improved mechanical performance for smart window applications

Polymer stabilized liquid crystals (PSLCs) have wide applications in smart windows and light shutters. However, for most applications, it requires low driving voltages and high mechanical performance, which is arduous to achieve both. Herein, a novel epoxy resin-based PSLC device is prepared showing improved electro-optical and mechanical properties simultaneously. This is benefited from the construction of a period polymer wall structure in liquid crystal matrix through cationic polymerization of epoxy monomers and preparation of multi-functional surfaces through self-assembly of silane mixtures. The multi-functional surfaces could ensure homeotropic alignment of liquid crystals and photo-polymerize with the polymer networks. As a result, the polymer-wall stabilized liqduid crystal (PWSLC) film with multi-functional surfaces shows lower (24%) saturation voltage, higher (20%) contrast ratio and improved (2.4 times) peel strength than the PSLC film with only vertical alignment surfaces. This research provides important reference to experiment and manufacture of reverse-mode dimming films for smart windows applications.

High-quality VO2 thin films sputter-deposited on borosilicate glass substrates for modulating solar transmission and thermal emission

M1-phase VO2 exhibits a reversible phase transition between the insulating and metallic states at T = ∼341 K, and VO2-based smart windows have been extensively studied. The smart window application requires the growth of high-quality VO2 films with a large resistivity change and small hysteresis width (ΔT) on glass substrates using a scalable deposition method such as sputtering. However, the polymorphic nature of VO2 makes it challenging to obtain high-quality VO2 films on ordinary window glasses (borosilicate and soda-lime glasses). Thus far, VO2 films sputtered on glass substrates have exhibited resistivity changes of 1.5–2 orders of magnitude and ΔT = 3–19 °C. In this study, we show that high-quality VO2 films with a resistivity change of 2.5−3.0 orders of magnitude and ΔT = 2 °C can be grown on borosilicate glass substrates via radio-frequency sputtering followed by thermal annealing. The simultaneous achievement of such a large resistivity change and small hysteresis width is highly encouraging not only for smart windows but also for other applications. With respect to the modulation of solar transmission and thermal emission with temperature, the performance levels of the produced VO2 films were 70−75 % of those expected from pure M1-phase VO2 films.

Rapid fabrication of polyoxometalate-enhanced photo responsive films from ethyl cellulose (EC) and polyvinylpyrrolidone (PVP)

Ethyl cellulose (EC), polyvinylpyrrolidone (PVP), and phosphomolybdic acid (PMoA) were the components of a new photochromic hybrid film composed of heteropoly acids (abbreviated EC-PVP/PMoA), created by solvent evaporation. The EC-PVP/PMoA mechanism, visible light photochromic behaviors, and microstructure were closely studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), ultraviolet-visible (UV–visible) spectroscopy, X-ray photo electronics (XPS), and Fourier transmission infrared spectroscopy (FTIR). FTIR spectra show that neither the core structures of EC, PVP, nor the Keggin structure of PMoA in the EC-PVP/PMoA composite hybrid film were damaged during fabrication. In the presence of oxygen, the yellowish transparent hybrid film exhibited reversible photochromism and significant photochromic reactivity, becoming blue in the presence of visible light. Upon heating the film at 90 °C for 1 h its photoresponsive properties were enhanced, making the blue color more vibrant and stable due to polyethylene glycol (PEG). The XPS spectra demonstrated a proton transfer procedure during the photochromic process, and the presence of Mo+5 species indicated a photoreduction interaction between the PMoA particles and the EC-PVP matrix. To the best of our knowledge, this is the first EC-PVP combined hybrid film with POMs with promising prospects for solar UV detection and smart glass windows applications.

Ten‐Million‐Fold Increase in the Electrical Conductivity of a MOF by Doping of Iodine Into MOF Integrated Mixed Matrix Membrane

AbstractThe development of electrically conductive membranes is essential for advancing future technologies like electronic devices, supercapacitors, and batteries. Newly synthesized doubly interpenetrated 3D‐Cd‐MOF (Metal‐Organic‐Framework) containing angular tetra‐carboxylate is found to display very poor electrical conductivity (10−11 S cm−1). However, it exhibits an exceptional ability to adsorb I2 (I2@Cd‐MOF) which shows increased electrical conductivity of the order of 10−8 S cm−1. Following these results, the Cd‐MOF is integrated into the PVDF‐PVP (Polyvinylidene fluoride‐Polyvinylpyrrolidone) polymeric mixed matrix membrane (MMM) and explores their I2 adsorption capabilities and electrical conductivities before and after I2 adsorption. Four polymeric MMMs with the loading of Cd‐MOF 0, 20, 40, and 50% are tested for their I2 adsorption ability and their respective electrical conductivities. The 50% Cd‐MOF‐loaded MMM is found to exhibit higher adsorption of I2 (685 mg g−1) and significant enhancement in conductivity from 10−11 to 10−4 S cm−1. The raise in the electrical conductivity by 10 million times is attributed to the synergistic interactions between I2, Cd‐MOF, PVDF, and PVP polymers as well as the increase in the concentration of charge carriers (holes) within the frameworks. This work serves as blueprint for controlling charge transfer in MMM to tune their electrical conductivity which opens a large window for advanced device applications.

Optimization of optical properties of nanocomposite films incorporating CWO and ITO nanoparticles for energy-saving window applications

Cesium tungsten oxide (CWO) and indium tin oxide (ITO) nanoparticles are potential candidates for application in energy-saving windows. However, most optical studies on these nanocomposite films lack systematic evaluation and design methods. In this work, the optical properties of spherical and cylindrical CWO and ITO nanoparticles under different geometric parameters based on the Lorenz–Mie and T-matrix theories are investigated, and spectral responses of CWO-PDMS and ITO-PDMS windows are calculated by solving the radiative transfer equation (RTE) using the Monte Carlo method. By evaluating and optimizing the geometric parameters of the nanocomposite films, energy-saving windows exhibit excellent optical performance, with a visible light transmittance that meets the indoor needs of the human eye (Tlum is about 0.6), and can shield most near-infrared light, especially CWO-PDMS windows (TNIR=0.04). Finally, a building energy consumption simulation analysis based on Energy Plus is conducted in three different cities: Jinan, Hong Kong, and Singapore. The results indicate that by adjusting the geometric parameters of nanoparticles, energy-saving windows can effectively reduce energy consumption in tropical and subtropical regions. This work provides guidance for the subsequent commercialization and experimental analysis of spectral selective composite films.

Opposition windows in Delhi’s water utility privatization: going beyond the multiple streams framework

ABSTRACT John Kingdon’s Multi-Stream Framework sheds light on the foundational conditions under which public policies get formulated and implemented. The coupling of the Problem, Policy, and Politics streams along with efforts by Policy Entrepreneurs opens the Opportunity Window for policy realization. Interpreting Kingdon’s MSF, a rich scholarship exists, which found evidence in support of this framework. Some instances of the opening up of multiple windows are found in MSF. However, two aspects remain unclear. First, what happens when multiple windows open, some of them could be opened by the opposing side simultaneously to the policy window? Second, no literature exists that discusses the application of multiple windows of the MSF. In this context, this paper takes the idea of multiple windows seriously along with illustrations from Delhi, India where we find that although a window of opportunity existed for the Government of National Capital Territory of Delhi, it could not privatize water supply. Our argument is that multiple windows opened up, some by the opposition that thwarted water privatization attempts of the state government.