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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]

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]

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]

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]

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]

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]

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 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]