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This research presents a new approach to developing an optical window film, leveraging the concept of charge‐transfer complex (CTC) intensification of colorless polyimide The window film demonstrates exceptional characteristics, including a tensile modulus of 8.4 GPa, a high total light transmittance of approximately 90%, and a yellow index below 3. This is the best‐recorded balance between mechanical strength and optical properties for a highly flexible optical film. Furthermore, the resulting film exhibits a pencil hardness grade surpassing 2H, alongside remarkable folding reliability, sustaining over 200,000 cycles of folding and unfolding. The excellent properties are ascribed to the unique supramolecular structure characterized by multiple hydrogen bonding and salt complexation interactions, significantly enhancing CTC intensification. [ABSTRACT FROM AUTHOR]

A negative voltage generator was developed that can be used in the drivers of smart window films (SWF), which have typical operating voltages of ± 8 to ± 10 V. It consists of four Negative Charge Pump (NCP) stages and a 4-phase non-overlapping Clock Generator (CG), where the 4 NCP stages are configurable by external digital signals. This generates a wide output voltage range necessary to control different SWF modes, such as opaque, transparent, and tinted modes. TSMC 0.18- μ m HV BCD (High-Voltage Bipolar-CMOS-DMOS) process was used to fabricate the proposed negative voltage generator on silicon. Measurement results demonstrate that at switching frequency (fsw) = 20 MHz, supplied voltage (VDD) = 4.5 V and Vin = GND, it generates a wide output voltage range of −3.9 to −14.0 V, achieving the widest voltage range among the prior works, which covers the required negative voltage range for SWF usage. The peak efficiency is measured on silicon to be 58.08%. [ABSTRACT FROM AUTHOR]

Phthalates are environmental endocrine disruptors that enter the human body through a variety of pathways and harm human health. The study aimed to explore the associations between phthalate concentrations in glass window films with dormitory characteristics, occupancy activities and habits, and environmental factors, of university dormitories. We surveyed these associations and measured the indoor environmental parameters of 144 dormitories from 13 universities in Beijing. Based on the results, we further explored the factors affecting phthalate concentrations using multivariate logistic regression. The results showed that phthalate concentrations in glass window films were associated with dormitory type, duration of occupancy, daily ventilation duration, window cleaning frequency, indoor relative humidity, light intensity, temperature, and particulate matter (PM10) concentration. To date, there have only been a few studies on the factors that influence phthalate concentrations in glass window films; therefore, further study is needed. Our findings determined the influence of external factors on the different types of phthalates in window films, which helps understand indoor phthalate pollution and evaluate human exposure based on phthalate concentrations in glass window films. [ABSTRACT FROM AUTHOR]

Window−film−integrated, near−infrared (NIR) absorption−based nanomaterials are of great interest in terms of numerous demands to reduce energy consumption, especially in buildings and vehicles. However, the question of how to effectively manage thermal energy generated from NIR harvesting in light−absorbing materials, rather than being wasted or causing negative effects, remains challenging. Herein, hollow copper sulfide (Cu2−xS) on colorless polyimide (PI) films, enabling them to be well−dispersed and robustly adhered, underwent in situ growth fabrication and were utilized as NIR−thermal−shielding and organic−pollutant−removal dual−function window films. Due to strong NIR absorbance, arising from the heavy hole−doping (copper cation deficiency), the Cu2−xS/PI composite film exhibited great promise for use in the filtration of the NIR spectrum. By monitoring Cu2−xS densities, its NIR−shielding efficiency reached 69.4%, with hundred−percent UV blocking and consistent performance within the reliability (85 °C/85%RH) tests over one week as well as 5000 bending cycles. The integration of the films into model cars and building windows exhibited excellent thermal−shielding performance upon exposure to direct sunlight. Moreover, benefiting from the distinctive distribution of Cu2−xS, the additional thermal energy (holes) generated in NIR absorption was successfully utilized. The densely surface−confined hollow structure of Cu2−xS on PI significantly endowed good formaldehyde catalytic capacity, with removal efficiency reaching approximately 72% within 60 min and a negligible decline after quartic reuse. These integration methodologies enable the promising fabrication of a high−performance, bifunctional window film combining thermal shielding and indoor organic pollutant removal. [ABSTRACT FROM AUTHOR]

A transparent radiative cooling (T-RC) film with low transmittance in solar spectra and selectively high emissivity in the atmospheric window (8–13 μm) is applied on roof glazing for building energy saving. To evaluate the performance of the T-RC film, two identical model boxes (1.0 m × 0.6 m × 1.2 m, L × W × H) were constructed and the inside air temperatures were measured in August in Ningbo, China. Results show that the maximum temperature difference between the two model boxes with and without the T-RC film was 21.6 °C during the experiment. A whole building model was built in EnergyPlus for the model box. With a good agreement achieved between the calculation results and the measured temperature data, the experimentally validated EnergyPlus model was then extended to an 815.1 m2 exhibition building with roof glazing to analyze the annual air conditioning (AC) energy consumption. The results show that by incorporating both the T-RC film's cooling benefit in summer and heating penalty in winter, the annual AC energy consumption of the exhibition building can be reduced by 40.9–63.4%, varying with different climate conditions.

[Display omitted] • Commercial flexible AR&AF optical films were prepared by high vacuum roll-to-roll sputtering with organic evaporation module. • Average reflectance and transmittance of 0.28 % and 95.1 % are observed for AR&AF cover window films in the wavelength of 420–680 nm. • The film-substrate bonding strength via introducing Si transition layer increases by more than 29%. Driven by the ever-increasing demand for curved, rollable, foldable, and stretchable displays, flexible and transparent cover window films using in curvature design have become an urgent need. Besides, the integration of other composite functional films (e.g., anti-reflective and anti-fingerprint) on the cover window film can be further realized through the development of commercial roll-to-roll (R2R) coating process. However, the widespread implementation of these optical films on a large scale is impeded by the challenges of poor durability. Here, we prepared anti-reflection & anti-fingerprint (AR&AF) cover window optical films on flexible polyethylene terephthalate with hard coating (PET-HC) substrates by introducing Si transition layers using high vacuum roll-to-roll sputtering with organic evaporation module. Compared to the original PET-HC-AR&AF films, the introduction of the Si transition layer can effectively improve the bonding properties of the film-substrate interface, while the optical properties are changed massively as the Si transition layer thickness increases. The balanced optical and mechanical properties are obtained via depositing ultra-thin 1 nm Si transition layer. Average reflectance and transmittance of 0.28 % and 95.1 % are observed in the wavelength of 420–680 nm. The vertical tensile testing shows that the film-substrate bonding strength increases by more than 29 % compared to PET-HC-AR&AF without Si transition layer pretreatment. Meanwhile, the number of surface scratches is sharply reduced after 3000 cycles of the steel-wool abrasion test and the water contact angle (WCA) is still over 90°. Due to the enhanced bonding strength between the organic substrate and the inorganic film material, roll-to-roll commercial-scale manufacturing process is available, which is essential for achieving cover window films for the next generation of flexible or foldable displays with high-performance and good mechanical properties. [ABSTRACT FROM AUTHOR]

The electricity consumption in residential/office buildings corresponded to 45% of the total annual electricity demand in hot-arid climates. This accounted for 27.2 TWh of electricity consumption with 14.2 MWh/capita/year in Kuwait. In this research, four offices in an educational building were equipped with a meteorological data logging system using temperature, humidity, and illuminance sensors. All four offices had double-glazed windows. Moreover, two offices were equipped with two types of commercially available window films. Two million data were stored in iCloud using Wi-Fi and an Internet of Things (IoT) system for the 3 months of June, July, and August 2019. Here, histograms and the kernel density estimation (KDE) of temperature/humidity were analyzed and compared for the two offices with/without 3M Neutral 20 window films. Two floors of the same building consisting of 31 offices were also modeled and simulated to study energy saving and CO2 footprint reduction using various window films. The results of simulations for the month of July 2019 using SOL 101 and SOL 102 window films, respectively, showed that about 250 kg and 255 kg of production of CO2 could be reduced and energy saving counted for 416 and 422 kWh. Measurements from offices with 3M Neutral 20% and 3M Neutral 70% window films for the month of July 2019 indicated that the carbon footprint could be reduced by about 82 kg and 0.43 kg and energy saving counted for 147.11 and 0.71 kWh, respectively. It was observed that an annual energy saving and CO2 footprint reduction of 2.76% could be achieved using window films in a hot-arid climate.

[Display omitted] • Climate changes are becoming a major concern in dry and hot climate countries. • A systematic method was developed to address the climate changes using PDF of thermo-solar properties. • Double peak patterns of temperature and humidity PDFs are reported for summer of the dry and hot climate. • Positive effects of window films in office buildings in summer of the dry and hot climate are discussed. This research attempts to develop a systematic method to address climate changes by studying temperature-humidity patterns as the two major meteorological parameters and to moderate these effects using a commercially available window film on interior windows of an office building with double-glazing. A three-floor educational building at Australian College of Kuwait (ACK) was equipped with temperature, humidity and illuminance sensors for two similar size offices, one with 3 M Neutral 20 window films. Total readings of 50,000 entries from each sensor was recorded every 3 min by a home-designed microprocessor-based logging system for three months of June, July, and August 2019. In parallel, the ACK building was simulated in EnergyPlus and DesignBuilder software and calibrated with the experimental measurements. Histograms and a probability density function (PDF) of temperature and humidity are built by a representative rational function as a model of main climate parameters variations. By examining min-mean-max values of data, it is observed that the office with window films has increased indoor humidity and, in most instances, reduced temperature by 2–5 °C compared to double-glazed bare windows which can significantly reduce cooling loads in extreme hot-arid climates. Simulation results are presented on the energy saved and the reduced CO 2 footprints by applying the solar window films in the ACK building. [ABSTRACT FROM AUTHOR]

Perhaps a billion birds die annually from colliding with residential and commercial windows. Therefore, there is a societal need to develop technologies that reduce window collisions by birds. Many current window films that are applied to the external surface of windows have human-visible patterns that are not esthetically preferable. BirdShades have developed a short wavelength (ultraviolet) reflective film that appears as a slight tint to the human eye but should be highly visible to many bird species that see in this spectral range. We performed flight tunnel tests of whether the BirdShades external window film reduced the likelihood that two species of song bird (zebra finch, Taeniopygia guttata and brown-headed cowbird, Molothrus ater) collide with windows during daylight. We paid particular attention to simulate the lighting conditions that birds will experience while flying during the day. Our results indicate a 75-90% reduction in the likelihood of collision with BirdShades-treated compared with control windows, in forced choice trials. In more ecologically relevant comparison between trials where all windows were either treated or control windows, the estimated reduction in probability of collision was 30-50%. Further, both bird species slow their flight by approximately 25% when approaching windows treated with the BirdShades film, thereby reducing the force of collisions if they were to happen. Therefore, we conclude that the BirdShades external window film will be effective in reducing the risk of and damage caused to populations and property by birds' collision with windows. As this ultraviolet-reflective film has no human-visible patterning to it, the product might be an esthetically more acceptable low cost solution to reducing bird-window collisions. Further, we call for testing of other mitigation technologies in lighting and ecological conditions that are more similar to what birds experience in real human-built environments and make suggestions for testing standards to assess collision-reducing technologies. [ABSTRACT FROM AUTHOR]

Millions of birds die in bird-window collisions in the United States each year. In specialized test settings, researchers have developed methods to alter window designs to mitigate collisions. However, few published studies provide pretest and posttest evaluations of mitigation treatment areas and untreated control areas on existing buildings. We initially monitored bird-window collisions at a single building on the University of Utah campus in Salt Lake City, Utah, USA, during winter 1 (November 9, 2017-January 2, 2018). We found 15 bird-window collisions, most under a portion of the building with a mirrored façade. To test a mitigation treatment, we installed Feather FriendlyR bird deterrent film on part of the mirrored façade after winter 1. The unmitigated areas of the same building served as a control area. We continued monitoring during the following winter 2 (November 15, 2018-January 12, 2019). The treated area collisions declined from seven before mitigation to two after mitigation, a 71% reduction. The control area had eight collisions at both times. Results of a generalized estimating equation yielded a significant area by season interaction effect (p = 0.03) and fewer collisions in the mitigated area than the control area at winter 2 (p = 0.03), supporting efficacy of the mitigation. In winter 2 we also expanded monitoring to eight total buildings to evaluate the risks of mirrored windows and proximity to fruiting pear trees (Prunus calleryana) and the benefits of bird-friendly glass. Bird-friendly glass, found on two buildings, included windows with permanent fritted dots or embedded ultraviolet patterns. We counted 22 collisions across the eight buildings. Mirrored windows and proximity to fruiting pear trees related to higher odds of bird-window collisions, based on separate generalized estimating equations. The best fit model included mirrored windows and pear trees. The two buildings with bird-friendly glass had only one collision, suggesting that these designs deter collisions, although the difference was not statistically significant. To publicize the study and to receive reports of additional bird collisions or fatalities on campus, we created a citizen science project on iNaturalist and engaged in additional outreach efforts that yielded 22 ad hoc reports. Many previous studies have documented Cedar Waxwing (Bombycilla cedrorum) collisions, but at relatively low numbers. Cedar Waxwings accounted for 31 of 34 identifiable collisions from the monitoring study and 4 of 21 identifiable collisions or fatalities from ad hoc reports. [ABSTRACT FROM AUTHOR]

While infants are developing, they are easily affected by toxic chemicals existing in their environments, such as semi-volatile organic compounds (SVOCs): phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). However, the specific living environment of infants, including increased plastic products and foam floor mats, may increase the presence of these chemicals. In this study, 68 air, dust, and window film samples were collected from homes, with 3- to 6-month-old infant occupants, to analyze phthalates, PAHs, PBDEs, and OPEs. High detection rates and concentrations suggest that these SVOCs are widespread in infant environments and are associated with cooking methods, smoking habits, the period of time after decoration, and room floors. The partitioning behavior of SVOCs indicates that the logarithms of the dust/gas-phase air partition coefficient (log K D) and the window film/gas-phase air partition coefficient (log K F) in homes are not at an equilibrium state when the logarithm of the octanol/air partition coefficient (log K OA) is less than 8 or greater than 11. Considering the 3 exposure routes, ingestion and dermal absorption have become the main routes of infant exposure to phthalates and OPEs, and ingestion and inhalation have become the dominant routes of exposure to PAHs and PBDEs. The total carcinogenic risk of SVOCs, which have carcinogenic toxicities, via ingestion and dermal absorption for infants in homes exceeds the acceptable value, suggesting that the current levels of these SVOCs in homes might pose a risk to infant health. Image 1 • Phthalates, PAHs, PBDEs, and OPEs are ubiquitous in infant homes. • Indoor partitioning of SVOCs with log K OA greater than 11 was not in equilibrium. • The total carcinogenic risk of SVOCs for infants exceeded the acceptable value. High detection rates and concentrations of SVOCs in infant homes are associated with elevated daily intakes of SVOCs for infants, and might pose a risk to infant health. [ABSTRACT FROM AUTHOR]

Abstract The study of indoor organic film on planar surfaces has been shown to be important to assess the transport and fate of organic pollutants in indoor environments. Limited research showed the relationship between equilibrium status of polycyclic aromatic hydrocarbons (PAHs) and the growth days for indoor window films. To accomplish this goal, indoor window film samples were collected in relation to film growth days in Northeast China. PAHs were frequently detected in window films collected during heating season (H-season), with concentrations significantly higher than that of non-heating season (NH-season). Accumulation characteristics of PAH suggested that PAH concentrations (ng/m2 film) were growing near-linearly with time. Partitioning status for PAHs between gas and window films under different accumulation stage from 1 to 11 weeks was investigated during the two seasons. The equilibrium status of PAHs in the films suggested that the octanol–air partition coefficient (log K OA) of the targeted PAHs should be approximately <12 in order to reached the equilibrium stage within 11 weeks of growth. For all the growth days, the proportion of samples that reached equilibrium status for PAHs in the indoor window film samples were further calculated. The total air concentration of the target PAHs were predicted, giving median values of 900 and 240 ng/m3 in H-season and NH-season, respectively. Human health risk posed by PAHs was calculated in this research showing greater risks found for H-season than NH-season. The estimated incremental lifetime cancer risks were considered as safe with values lower than the WHO recommended guideline. Graphical abstract Unlabelled Image Highlights • The concentrations of PAHs (ng/m2) were growing near-linearly with film growth days. • PAHs in indoor window films were significantly influenced by central heating. • Different equilibrium statuses were noted for lower mass PAHs and higher mass PAHs. • PAHs with log K OA <11.3 can reach the equilibrium stage within 11 weeks of film growth. • Estimated human exposures to PAHs were higher in heating season than non-heating season. [ABSTRACT FROM AUTHOR]

Colorless polyimide (CPI) film is one of promising candidates for a foldable display because of its excellent mechanical and optical properties. To achieve a good and high reliable foldability, engineers must take into account thickness for foldability and mechanical hardness for pen touch function. To compromise this trade‐off relationship, LG Display chose CPI as a base film of the cover window and double‐sided thin hard coating for a pen touch solution. This paper shows why LG Display choose the proposed configuration with detail data. [ABSTRACT FROM AUTHOR]

SK Innovation and SK ie technology have developed and commercialized cover window films (FCW®) composed of functional coatings on transparent polyimide (PI) film for a foldable displays. We report on the development of PI film with high visual clarity, which can provide glass‐like feel to public users. Advances were achieved by engineering drying kinetics on the process of film fabrication, and the technology is applied to the commercial product of transparent PI film. [ABSTRACT FROM AUTHOR]

Developments in diode pumped alkali laser (DPAL) systems have been impeded because of the catastrophic failure of laser windows. The window's failure is caused by localized laser-induced heating of window material. This heating is believed to occur due to increases in absorption on or near the surface of the window. This increase is believed to be caused by either adsorption of carbon-based soot from the collisional gas or by the diffusion of rubidium into the bulk material. The work presented here focuses on the diffusion of Rb into the bulk window materials and strives to identify a superior material to use as windows. The results of this research indicate that aluminum oxynitride (ALON), sapphire, MgAl2O4 (spinel), and ZrO2 are resistant to alkali-induced changes in optical properties. [ABSTRACT FROM AUTHOR]

Concentrations of 13 organophosphate ester flame retardants (OPEs) were measured in air, dust and window wipes from 63 homes in Canada, the Czech Republic and the United States in the spring and summer of 2013 to look for abundances, differences among regions, and partitioning behavior. In general, we observed the highest concentrations for halogenated OPEs, particularly TCEP, TCIPP and TDCIPP, and also non-halogenated TPHP. Differences between regions strongly depended on the matrix. The concentrations of OPEs in dust were significantly higher in the US than in Canada (CAN) and Czech Republic (CZ). CZ had the highest concentrations in window film and CAN in air. ΣOPE concentrations were 2–3 and 1–2 orders of magnitude greater than ΣBFRs in air, and dust and window films, respectively. We found a significant relationship between the concentrations in dust and air, and between the concentrations in window film and air for OPEs with log K OA values < 12, suggesting that equilibrium was reached for these compounds but not for those with log K OA > 12. This hypothesis was confirmed by a large discrepancy between values predicted using a partitioning model and the measured values for OPEs with log K OA values > 12. [ABSTRACT FROM AUTHOR]

In recent years, cool materials that have high solar reflectivity and thermal emittance properties have been applied for building surfaces in the urban environment. However, when such highly reflective materials reflect all or part of the solar radiation downwards or towards the ground, there are concerns that it leads to deterioration of the thermal environment of pedestrian spaces. A newly developed near-infrared (NIR) upward reflective solar control window film (URSCF) has come to the market. The film reflects NIR upwards to the sky, and shields a building’s interior from solar radiation without deteriorating the thermal environment of pedestrian spaces. In order to quantify the reflected solar radiation, it is necessary to clarify the reflectivity and transmissivity properties of retro-reflective materials, which is desirably performed through measurement in a stable environment using artificial light sources. This required development of the evaluation methods using apparatus including an integrating sphere, allowing the measurement of directional-hemispherical spectral reflectivity at large incident polar angles, as well as the selective measurement of directional-upward spectral reflectivity from retro-reflective surfaces. It was confirmed that these results are appropriate through verification with the results obtained from commercially available apparatus and from optical simulations. With respect to the effect of NIR URSCF, it was confirmed that downward reflectance of solar radiation at the incident polar angle of 70° and the incident azimuth angle of 0° was approximately half of that of conventional specular reflective solar control window film. [ABSTRACT FROM AUTHOR]

Daylight redirecting systems with vertical windows have the potential to offset lighting energy use in deep perimeter zones. A microstructured prismatic film designed for such use was characterized using goniophotometric measurements and ray tracing simulations. The synthetically-generated bidirectional scattering distribution function (BSDF) data were shown to have good agreement with limited measured data for normal incident angles (0–60°). Measured data indicated that the prismatic film was most efficient when vertical angles of incidence were between 18 and 35° and within ±45° of normal incidence to the plane of the window so maximum energy savings across the full depth of the zone occurred over the equinox to winter solstice period. Annual lighting energy use and visual comfort in a deep open plan office zone were evaluated using the Radiance three-phase method in several climates and for south and east-facing window orientations. Lighting energy savings were 39–43% for a 12 m (40 ft) deep south-facing perimeter zone compared to the same zone with no lighting controls. The prismatic film with and without a diffuser controlled glare for views parallel to the window but produced glare for seated viewpoints looking toward the window. At mature market costs, the system was projected to have a simple payback of 2–6 years. Technical challenges encountered throughout the evaluation led to improvements in measurement and modeling tools and stressed the importance of having accurate input data for product development. [ABSTRACT FROM AUTHOR]

Concentrations of more than 20 brominated flame retardants (FRs), including polybrominated diphenyl ethers (PBDEs) and emerging FRs, were measured in air, dust and window wipes from 63 homes in Canada, the Czech Republic and the United States in the spring and summer of 2013. Among the PBDEs, the highest concentrations were generally BDE-209 in all three matrices, followed by Penta-BDEs. Among alternative FRs, EHTBB and BEHTBP were detected at the highest concentrations. DBDPE was also a major alternative FR detected in dust and air. Bromobenzenes were detected at lower levels than PBDEs and other alternative FRs; among the bromobenzenes, HBB and PBEB were the most abundant compounds. In general, FR levels were highest in the US and lowest in the Czech Republic — a geographic trend that reflects the flame retardants' market. No statistically significant differences were detected between bedroom and living room FR concentrations in the same house ( n = 10), suggesting that sources of FRs are widespread indoors and mixing between rooms. The concentrations of FRs in air, dust, and window film were significantly correlated, especially for PBDEs. We found a significant relationship between the concentrations in dust and window film and in the gas phase for FRs with log K OA values < 14, suggesting that equilibrium was reached for these but not compounds with log K OA values > 14. This hypothesis was confirmed by a large discrepancy between values predicted using a partitioning model and the measured values for FRs with log K OA values > 14. [ABSTRACT FROM AUTHOR]

Indoor window film samples were collected in buildings during 2014-2015 for the determination of six phthalate diesters (PAEs). Linear regression analysis suggested that the film mass was positively and significantly correlated with the duration of film growth (from 7 to 77 days). PAEs were detected in all window film samples (n = 64). For all the samples with growth days ranged from 7 to 77 days, the median concentrations of total six PAEs (∑6PAEs) in winter and summer window film samples were 9900 ng/m² film (2000 µg/g film) and 4700 ng/m² film (650 µg/g film), respectively. Among PAEs analyzed, di-2-ethyl-hexyl phthalate (DEHP) was the major compound (71 ± 9.7%), followed by di-n-butyl phthalate (DBP; 20 ± 7.4%) and diisobutyl phthalate (DiBP; 5.1 ± 2.2%). Positive correlations among PAEs suggested their common sources in the window film samples. Room temperature and relative humidity were negatively and significantly correlated with PAEs concentations (in ng/m²). Poor ventilation in cold winter in Noreastern China significantly influenced the concentrations of PAEs in window film which suggested higher inhalation exposure dose in winter. The median hazard quotient (HQ) values from PAEs exposure were below 1, suggesting that the intake of PAEs via three exposure pathways was considered as acceptable. [ABSTRACT FROM AUTHOR]

For realizing foldable displays, transparent and robust cover window film consisting of hard coating and the polymeric substrate should be developed. However, in terms of practical usage, current state-of-the-arts show significant limitations caused by low reliability and incompatibility of hard coating and substrate. Here, we propose a new type of hard coating/substrate all-in-one composite film for the cover window of a foldable display. The film combines siloxane-based hard coating and glass-fabric reinforced hybrid substrate, and that has excellent mechanical robustness and environmental stability. The chemical bond between hard coating layer and hybrid substrate improves compatibility between them, and thereby yields excellent robustness and reliability. The composite film has high optical transparency (90% at 550 nm), surface hardness (6 H), and flexibility (3-mm bending radius). Furthermore, we investigate the reliability of all-in-one film against repeated folding, and against static folding at various severe environments, by direct visualization of strain distribution. Our hard coating/substrate all-in-one film provides a significant breakthrough toward reliable cover window film for future foldable display applications. [Display omitted] [ABSTRACT FROM AUTHOR]

We have simulated unique textured window films that capture solar radiation without compromising the win- dow's transparency by scattering infrared light toward photovoltaic strips located at the edges of the window. These films are ideal for powering electrochromic glass, which is difficult to install as each window requires its own power source. Our most promising design consists of an embedded array of 35° cones coated with a five-layer SiO2-Ag stack that was simulated to direct 1.4% of the incident light toward the edges and generate 1 W of power under a collimated 1000 W/m² AM1.5G source at 60° and an average of 0.5 W over a full year when applied to a 1 m x 1 m window. The internal visible transmittance of the window with the applied film is 95% at normal incidence, and remains above 85% for viewing angles up to 60°. The haze is 0.6% at normal incidence and 3.9% at 60°. [ABSTRACT FROM AUTHOR]

Solar control films are designed to absorb or reflect the incident solar radiation, in order to reduce solar transmission through window glass. In the present study, the glass surface temperatures were measured for selected solar window films on various applications, and compared to the cases of the same window glass types without solar window films. Dynamic simulation models are also developed with the aid of the building energy simulation program EnergyPlus. After experimental validations, the computer models are used to evaluate the energy saving potentials of the subject samples of solar window films as applied onto glazing of three different function rooms in Hong Kong, namely office, shopping mall and hotel guest room. The results show that the thermal performance of the film applications on clear glass is better than on tinted or laminated glass windows. Solar films have very good energy saving potential when applied to all three functional areas in commercial buildings, and the best results are found in office applications. [ABSTRACT FROM AUTHOR]

The desire for foldable display seems to be heading toward its zenith. However, its mass production is still impeded by a few technical challenges, specifically, development of flexible cover window films. This invited paper demonstrates innovative flexible hard coating (Flex9H®) for foldable display cover plastic films, which exhibits glass-like pencil hardness, plastic-like flexibility and excellent optical transparency simultaneously. [ABSTRACT FROM AUTHOR]

Retrofitting existing windows with a safety window film, to improve impact resistance, has been increasing along with the awareness of potential attacks on strategic buildings. However, current classification of glass panels is based solely on discrete outcomes of standardised tests without any instrumentation. In this paper, a versatile small-scale drop weight test set-up is conceived which is widely instrumented (accelerometer, force sensor, displacement sensor, high-speed visual observation) in order to gain more insight in the mechanical impact response of glass fitted with a safety window film. The elastic response, determined by the much higher stiffness of the glass, was very reproducible. The impacted surface (glass vs. film side) had a large influence, whereas the tensioned surface and laminated surface (air vs. tin side), do not. The film thickness only had an influence when the film was tested separately (without glass substrate) or in case of a soft impact of glass. [ABSTRACT FROM AUTHOR]

Organic films were collected from indoor and outdoor window surfaces in two large cities in southern China, Guangzhou and Hong Kong, and analyzed to quantify the polycyclic aromatic hydrocarbons (PAHs). In the glass films, the highest concentration of total PAHs, predominantly phenanthrene, fluorene, fluoranthene, and pyrene, was found to be l400 ng/m2. The concentrations of PAHs in Guangzhou were usually higher than those in Hong Kong. In general, higher concentrations of PAHs on exterior window films in comparison with interior window films in both cities indicated that the outdoor air acted as a major source of pollution to the indoor environment. However, indoor air was a major source of some light-weight PAHs. Measurements made over time indicated that the growth rates of light-weight PAHs on window surfaces were fast at the beginning and then gradually reached a consistent level, whereas heavy-weight PAHs exhibited near-linear accumulation during the 40 days sampling period. [Copyright &y& Elsevier]

Abstract: The objective of this study was to understand the energy savings from applying solar window films in a commercial building with large, curtain wall areas in Shanghai, China. eQUEST was used to simulate the annual building performance with and without the solar window film. The simulation model was calibrated against the measured monthly and daily electrical consumption. The simulation results indicated that two factors significantly influence the effect of the window film. These factors include the position of the installed window film and the configuration of the original glazing system. The effect of the window film on the performance of the curtain wall glazing system varies greatly, depending on the type of film and how it is applied. The film can decrease the shading coefficient and solar heat gain coefficient by 44% and 22% if applied on the outside and inside of the existing windows, respectively. For a double pane, low-E glazing system, the building cooling load through the windows on design day is reduced by 27.5% and 2.2% for outside and inside window films, separately. Adding the window film inside of the curtain wall was not effective because the increased window conductive heat transfer offsets the decreased cooling load from solar radiation. [Copyright &y& Elsevier]

The thin organic film that builds up on the exterior surface of windows has been proposed as a ubiquitously available passive sampler for semi-volatile organic contaminants (SOCs) in urban air. Readily available school windows were sampled in Stockholm city centre and suburban locations in both winter and summer season to evaluate the putative usefulness of this matrix for assessing the integrated load of urban air pollution by polycyclic aromatic hydrocarbons (PAHs). The window-area normalised concentrations indicated more PAH contamination in the winter than in the summer in both the city centre and suburban locations, with highest concentrations in the city centre in the winter (∑PAH43 451–467ngm−2). However, normalising the PAH load to the amount of fatty window film, as measured by extractable organic matter (EOM), gave a more homogeneous picture with the EOM-normalised PAH load being inseparable both between summer and winter and between city centre and suburban locations. To evaluate the possibility of quantitatively employing urban window films as a means to provide predicted environmental concentrations of PAHs in air (PECair), window film–air partition coefficients of PAHs were estimated using a set of coupled linear free energy relationships and physico-chemical properties of PAHs. Assuming dynamic equilibria between PAHs in air and dissolved in the window film, the obtained PECair from the window films were consistently overestimating the urban vapour-phase PAH concentrations by factors 4–135. This discrepancy is quantitatively consistent with a strong and overwhelming association with black carbon aerosol particles accumulated in the window film. For SOCs that have a lower tendency to associate with black carbon, bulk window film concentrations may work better than for PAHs to estimate their vapour-phase concentrations in urban air. [Copyright &y& Elsevier]

People are exposed to ambient solar ultraviolet (UV) radiation throughout their daily routine, intentionally and unintentionally. Cumulative and excessive exposure to UV radiation is the behavioral cause to skin cancers, skin damage, premature skin aging, and sun-related eye disorders. More than one million new cases of skin cancer were diagnosed in the United States this year. UV radiates directly and diffusely scattered by the various environmental and atmospheric conditions and has access to the skin from all directions. Because of this diffuse UV radiation, a person situated under a covering, such as the roof of a car or house, is not completely protected from the sun's rays. Because shade structures do not protect effectively against UV radiation, there have been major advances in photoprotection of glass by the development of specially designed photoprotective windows and films. It is the purpose of this collective review to highlight the photoprotective windows and films that should be incorporated into residential, commercial, and school glass windows to reduce sun exposure. Low-emittence (low-E) coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface to reduce the U-factor by suppressing radiative heat flow as well as to limit UV radiation. The exclusive Thermaflect® coating uses the most advanced, double-layer soft coat technology to continue to deliver top performance for UV protection as well as prevent heat loss in the home. This product blocks 87% of UV radiation and has an Energy Star® certification in all climate zones. Tints and films have been another important advance in glass photoprotection, especially in automobiles. Quality widow film products are high-tech laminates of polyester and metallized coatings bonded by distortion-free adhesives. The International Window Film Association provides members with accreditation in solar control films, safety film... [ABSTRACT FROM AUTHOR]

Window is the least energy-efficient part of buildings or cars; however radiative cooling, as an efficient energy-zero technology, is rarely used in window films of buildings or cars. Therefore, we in this work fabricated a transparent dual-layer film for daytime radiative cooling, which contained a layer of polymethyl methacrylate (PMMA) uniformly mixed with modified silica nanoparticles (SiO 2 NPs) and a layer of silver. The dispersion of the modified SiO 2 NPs in PMMA was notably improved through in-site grafting PMMA, which resulted in a high transparency of the radiative cooling film even at a high filling fraction of SiO 2 (20 wt%). Owing to the strong broadband IR absorbance/emittance (ε AW = 94.3%) and high sunlight reflectance (ρ ≈ 50%), the dual-layer film possessed a high cooling capacity and could achieve an average temperature drop of 1.4 °C than pure PMMA film in the daytime outdoor cooling measurement. In the simulated automotive cooling test, the dual-layer film cooled the interior space up to 6 °C below ambient temperature during peak solar hours. The excellent optical property and cooling capability exhibit a promising application of building and car windows for cooling their interior spaces. [Display omitted] • A transparent dual-layer film with broadband infrared emission for efficient daytime radiative cooling was developed. • It can be used as a window film due to its high transparency other than daytime radiative cooling performance. • This work further broadens the potential application of daytime radiative cooling technology toward high efficiency. [ABSTRACT FROM AUTHOR]

• Vertically aligned Ni flakes (VANF) window film has 90% forward transparency. • Nanoscale Ni flakes array serve as shades to cut the high-angled incident sunlight. • VANF film can cut the maximum 73% of the sunlight. • VANF film was constructed by magnetically displacement of Ni flakes. Every year, more than 20% of the energy consumption in the United States and more than 10% of the global consumption is used towards HVAC (Heating, Ventilating, Air-Conditioning) systems in buildings. Although continued efforts in advancing renewable energy, efficient appliances, and smart building systems are desired, the most critical factors that cause extensive indoor energy consumption are thermal leakage and thermal waste generation. We demonstrate a smart window film that allows natural lighting with a clear view while blocking oblique incident sunlight to make the building interior cooler without using electricity or generating heat. Building upon the concept of, often overlooked, traditional window shades and privacy window films, we emphasize and elevate the application and impact of using magnetically arranged nanoscale material for energy conservation purpose in buildings. By embedding vertically aligned Ni flakes (VANF) in a polymer matrix film, nanoscale mirror array serve as shades to block the high-angled incident sunlight, blocking approximately 73% of total solar irradiance and bringing down the indoor temperature by 1.92 °C during the daytime in a model house while providing nearly 90% transparency. Global application was simulated by applying the respective solar angle and intensity at selected latitudes, indicating their potential. This passively energy-conserving smart film is a low cost, maintenance free, and simple product for users and easy-to-manufacture product for the industry. [ABSTRACT FROM AUTHOR]

• The new synthesis route of siloxane-based materials is presented. • The key factor of hardness and modulus of hard coating material is both Mw and PDI. • The hard coating layer is studied with nanoindentation analysis. • 2-step sol-gel synthesized hard coating improved surface hardness by 32 %. Flexible but still hard coating materials have been paid attention for applications in flexible electronic devices, as efforts to substitute glasses. However, there have been little approaches to find out control parameters determining their flexibility and hardness. Here, we present reaction-controlled polysilsesquioxane (PSQ) resins with improved flexibility and hardness. In this study, the effects of various reaction conditions on the molecular weight of the PSQ resins are investigated in terms of reaction time, and absence of byproducts, accompanying the analysis of mechanical properties of the corresponding films using nanoindentation. With the reaction-controlled PSQ resins by removing byproducts such as alcohols, the molecular weight could be increased up to 44 % compared to PSQ containing the byproducts. The surface hardness and modulus of hard coating films are also enhanced by 32 % and 13 % compared to that from original PSQ resin, respectively. Finally, we demonstrate folding reliability for 100 k bending cycles at various bending radii of 6 to 1 mm that shows improved warpage property with less irreversible deformation upon the folding test. [ABSTRACT FROM AUTHOR]

To evaluate the performance of window films of an environmental cell in electron microscopy, the “effective thickness” is defined and measured. Latex balls are put on a film and scanned with an electron beam. The latex balls act as a standard in the measurement of electron transmission because its mass density and size are known. As the electron transmission depends on the measuring conditions such as the electron energy and the aperture angle, it is converted into an inherent parameter of films, the effective thickness, under the assumption that the absorption coefficient is proportional to the mass density. The error in measurement is about 6%. [ABSTRACT FROM PUBLISHER]

The thickness characterization of transparent protective coatings on functional, transparent materials is often problematic. In this paper, a toolbox to determine the thicknesses of a transparent coating on functional window films is presented. The toolbox consists of a combination of secondary ion mass spectrometry and profilometry and can be transferred to other transparent polymeric materials. A coating was deposited on designed model samples, which were characterized with cross-sectional views in transmission and in scanning/transmission electron microscopy and ellipsometry. The toolbox was then used to assess the thicknesses of the protective coatings on the pilot-scale window films. This coating was synthesized using straightforward sol-gel alkoxide chemistry. The kinetics of the condensation are studied in order to obtain a precursor that allows fast drying and complete condensation after simple heat treatment. The shelf life of this precursor solution was investigated in order to verify its accordance to industrial requirements. Deposition was performed successfully at low temperatures below 100 °C, which makes deposition on polymeric foils possible. By using roll-to-roll coating, the findings of this paper are easily transferrable to industrial scale. The coating was tested for scratch resistance and adhesion. Values for the emissivity (ε) of the films were recorded to justify the use of the films obtained as infrared reflective window films. In this work, it is shown that the toolbox measures similar thicknesses to those measured by electron microscopy and can be used to set a required thickness for protective coatings. [ABSTRACT FROM AUTHOR]