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We fabricated anti‐glare (AG) coatings on glass sheets by spraying alkoxide‐derived silica sols and demonstrated that the water‐to‐alkoxide ratio is one of the key factors for improving AG performance and sol stability. We synthesized silica sols using tetraethylorthosilicate (TEOS), water, nitric acid, and denatured ethanol and sprayed them on sheets of chemically strengthened glass. The molar ratios of water to TEOS (r) were 3, 7, and 14. The sol with r = 7 provided a higher arithmetic‐mean height (Sa), smaller autocorrelation length (Sal), and better optical properties (lower gloss, higher haze, and lower sparkle level) than the sol with r = 3. An excessive amount of water at r = 14 yielded a large Sal and a high sparkle level. As the storage time of the sols increased, higher r values caused a more pronounced increase in Sa. Although none of the sols showed noticeable temporal changes during dynamic light scattering measurements, solutions with higher r values exhibited a more remarkable reduction in the retention time during liquid chromatography with a styrene‐divinylbenzene matrix. Hence, an excessive amount of water was thought to cause hydrophilization of the polymerized species during storage. [ABSTRACT FROM AUTHOR]

The application of the expanded polystyrene (EPS) waste to the functional material is still a challenge. The hydrophobic property of polystyrene has a potential to create a superhydrophobic surface. Here, we use expanded polystyrene waste to coat surfaces in two different ways—spray coating and dip coating—to produce superhydrophobic surfaces for food packaging. The ZnO was employed to make the surface rougher. However, the combination of ZnO and EPS waste produces only a hydrophobic surface. For spray coating and dip coating, the maximum water contact angle is 119° and 125° respectively. The scanning electron microscope (SEM) picture reveals many holes that increase the surface's roughness. The hydrophobic surface significantly cuts down on cleaning time. According to the food packaging parameter test mandated by the Indonesian Food and Drug Administration (BPOM) (BPOM regulation No. 20, 2019), the coating complies with heavy metals and ethanol stimulant migration testing requirements for food packaging. However, the migration condition in acetic acid stimulant surpasses the maximum standard. The total migration in 3% acetic acid stimulant (40°C for 10 days) is 22.95 mg/dm2 while the maximum value is 10 mg/dm2.

Structural color coatings with brilliant color is important in practical applications, such as aesthetic decoration, bionic skins, colorimetric sensors, and other color‐related fields. However, the intrinsic conflict between fast self‐assembly and bright structural color hinders their widespread applications. Here, cholesteric liquid crystal elastomer (CLCE) coatings with brilliant color and mechanochromic response are developed by spraying the cholesteric liquid crystal (CLC) paints followed by evaporation‐induced self‐assembly (EISA) and photocuring. The Marangoni flow within the paints, which drives the orientation of liquid crystal molecules along the flow track in the EISA process, is found to be crucial for achieving both rapid self‐assembly time (60 s) and high reflectivity structural color (42%). The as‐prepared CLCE coatings present uniform structural colors, circularly polarized reflection, and mechanochromic response. Several proof­of­concept applications are also demonstrated, including patterned CLCE coatings on flat substrates, fully covered CLCE coatings on 3D objects, and non‐spectral colors via additive mixing method. The research disclosed herein provides unprecedented levels of efficiency and reliability for preparing structural color coatings. [ABSTRACT FROM AUTHOR]

Hybrid organic‐inorganic perovskite solar cells (PSCs) have rapidly advanced in the new generation of photovoltaic devices. As the demand for energy continues to grow, the pursuit of more stable, highly efficient, and cost‐effective solar cells has intensified in both academic research and the industry. Consequently, the development of scalable fabrication techniques that yield a uniform and dense perovskite absorber layer with optimal crystallization plays a crucial role to enhance stability and higher efficiency of perovskite solar modules. This review provides a comprehensive summary of recent advancements, comparison, and future prospects of scalable deposition techniques for perovskite photovoltaics. We discuss various techniques, including solution‐based and physical methods such as blade coating, inkjet printing (IJP), screen printing, slot‐die coating, physical vapor deposition, and spray coating that have been employed for fabrication of perovskite modules. The advantages and challenges associated with these techniques, such as contactless and maskless deposition, scalability, and compatibility with roll‐to‐roll processes, have been thoroughly examined. Finally, the integration of multiple subcells in perovskite solar modules is explored using different scalable deposition techniques. [ABSTRACT FROM AUTHOR]

In this study, graphene–silver (G–Ag) nanocomposite films on glass substrates were synthesized and characterized using a spray method with different concentrations (0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 g) of AgNO3. The films were heated to 300 °C, and X-ray diffraction and scanning electron microscopy were used to analyze the crystalline structure and morphology of the G–Ag nanocomposites, respectively. UV–visible/NIR spectrophotometry was used to determine the optical properties of the films, which showed improved transparency and conductivity due to the attachment of silver nanoparticles to the graphene sheets. The results confirmed the successful attachment of silver nanoparticles to graphene as shown by the XRD and SEM analyses, and the presence of surface plasmon resonance (SPR) of the AgNPs was confirmed by the absorption peak at 410–430 nm in the UV–Vis spectra. Depicts a cross section of a thin film with a thickness of approximately (500 nm). XRD analysis indicated the presence of Ag and graphene, while Raman spectroscopy showed a slight difference between the spectra of the nanocomposites and AgNPs. UV–visible spectroscopy analysis revealed the presence of AgNPs on the graphene films and their surface plasmon resonance properties; the graphene–silver nanocomposite films were found to be a promising method for fabricating thin, homogeneous graphene films with improved optical properties, which could have potential applications in optoelectronics, touch screens and solar cells. It was found that the calculated figure of merit (FOM) increased with increasing Ag concentration and reached a maximum value of 0.25, indicating that the G–Ag nanocomposite films have a good balance between optical transparency and electrical conductivity. Overall, this study provides valuable insights into the synthesis and characterization of G–Ag nanocomposite films and their potential for various applications. [ABSTRACT FROM AUTHOR]

Herein, we investigate the potential application of a composite consisting of PEDOT:PSS/Graphene, deposited via spray coating on a flexible substrate, as an autonomous conducting film for applications in wearable biosensor devices. The stability of PEDOT:PSS/Graphene is assessed through electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and linear polarization (LP) during exposure to an artificial sweat electrolyte, while scanning electron microscopy (SEM) was employed to investigate the morphological changes in the layer following these. The results indicate that the layers exhibit predominant capacitive behavior in the potential range of −0.3 to 0.7 V vs. Ag/AgCl, with a cut-off frequency of approximately 1 kHz and retain 90% capacity after 500 cycles. Aging under exposure to air for 6 months leads only to a minor increase in impedance, demonstrating potential for storage under non-demanding conditions. However, prolonged exposure (>48 h) to the artificial sweat causes significant degradation, resulting in an impedance increase of over 1 order of magnitude. The observed degradation raises important considerations for the long-term viability of these layers in wearable biosensor applications, prompting the need for additional protective measures during prolonged use. These findings contribute to ongoing efforts to enhance the stability and reliability of conducting materials for biosensors in health care and biotechnology applications. [ABSTRACT FROM AUTHOR]

NASA seeks to develop technologies to mitigate dust accumulation from planetary surfaces on robotic and human systems hardware during planned space exploration missions. With a return to the Lunar surface, lunar dust threatens the durability and reusability of components and vehicles due to its fine, jagged morphology and highly abrasive nature. Lunar dust consists of particles less than 60 μm in size that are chemically reactive, electrostatically and sometimes magnetically charged. Unique materials and technologies that reduce or mitigate lunar dust adhesion will be critical to support long duration missions and eventual sustained presence on the lunar surface. The goal of this work was to prepare dust resistant, space durable polymer films to satisfy dust accumulation mitigation needs for future NASA missions. In this regard, several graphene coated polyimide thin films have been developed with surface resistivity properties in the range of 103 Ω/sq to 1011 Ω/sq and evaluated for their dust adhesion performance. Raman spectroscopy was used to characterize and assess the quality of graphene ink coated sheets while surface resistivity measurements were used to assess electrical conductivity. Scratch testing and abrasion resistance measurements were used to evaluate overall abrasion performance. Water contact angle and optical microscopy were used to evaluate changes in surface topography and chemistry. Graphene coated polyimide surfaces with charge dissipative resistivity (106 Ω/sq) demonstrated a minimum in residual particle areal coverage compared to conductive and insulating surfaces. Graphene ink/polymer thin film coated polyimide sheets (15 cm X 15 cm area, 75 μm thickness) are shown in order of decreasing sheet surface resistivities ranging from 103 Ω/sq, 104 Ω/sq, 106 Ω/sq, 108 Ω/sq, 1010 Ω/sq, and 1011 Ω/sq. Uncoated Kapton®, with sheet surface resistivity 1014 Ω/sq, is shown for comparison. [Display omitted] • Graphene ink coated polyimide sheets with surface resistivities in the range of 102 Ω/sq to 1012 Ω/sq have been prepared. • A significant improvement in scratch hardness (∼2 times) was observed for the coated substrates compared to the uncoated. • A minimum in residual particle areal coverage was observed for surfaces that exhibited intermediate surface resistivity values. • Dust resistant polymer films have been demonstrated for graphene coated polyimide sheets. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency (NUE) (50%) and raising severe environmental pollutions. Controlledrelease nitrogen fertilizers (CRNFs) can control the release of N nutrients to NUE in crop production. Different methods were used to develop new CRNFs. However, different CRNF technologies are still underdeveloped due to inadequate controlling on N releasing time and/or unsustainable diffusion. The study on the influences of CRNF processing parameters on microbial conditions are lacking when the CRNFs composed of various bio-ingredients such as biochar, composts, and biowaste. The complexity of processing methods, material biodegradability, and other physical properties make current CRNFs of questionable value in agricultural production. This research aims to develop a novel biochar-compost-based controlled-release urea fertilizer (BCRUF) to preserve microbial properties carried by the compost. The BCRUF was synthesized by pelletizing the 50:50 (dry, wt/wt) mixture of biochar and compost. BCRUF was loaded with urea and then spray-coated with polylactic acid (PLA). The releasing time of two types of BCRUFs, coated and uncoated with PLA, for 80% of N release in water was up to 6 h at three different temperatures (4, 23, and 40 °C), compared to conventional urea fertilizer and commercial environmentally smart N (ESN) fertilizer. The releasing time of coated BCRUF for 80% N release in soil was up to 192 h (8 days). Fourier-transform infrared spectroscopy (FTIR) analysis revealed that no new functional groups were found in the release solution, indicating no new chemical hazards generated. The differential scanning calorimetry (DSC) tests also verified that its thermal stability could be up to 160 °C. The microbe populations in the BCRUF pellets were reduced after the pelleting and drying processes in BCRUF fabrication, but a few bacteria can endure in the air-drying process. BCRUF pellets soaked in water for 4 days retained some bacteria. The BCRUF showed very promising characteristics to improve NUE and sustainability in agricultural production. [ABSTRACT FROM AUTHOR]

This study explores, through a full factorial experimental design, the effects of graphite concentration and spray flow rate on the morphology, thickness, and tribological performance of graphite coatings for potential tribological applications. Coatings were applied to rough substrates using varying concentrations and flow rates, followed by analysis of their morphological characteristics, roughness, thickness, coefficient of friction (COF), and wear behavior. The results revealed distinct differences in the coating morphology based on flow rate, with low-flow-rate coatings exhibiting a porous structure and higher roughness, while high-flow-rate coatings displayed denser structures with lower roughness. A COF as low as 0.09 was achieved, which represented an 86% reduction compared to uncoated steel. COF and wear track measurements showed that thickness was influential in determining friction and the extent of wear. Flow rate dictated the coating structure, quantity of transfer film on the ball, and the extent of graphite compaction in the wear track to provide a protective layer. SEM and elemental analysis further revealed that graphite coatings provided effective protection against wear, with graphite remaining embedded in the innermost crevices of the wear track. Low flow rates may be preferable for applications requiring higher roughness and porosity, while high flow rates offer advantages in achieving denser coatings and better wear resistance. Overall, this study highlights the importance of optimizing graphite concentration and spray flow rate to tailor coating morphology, thickness, and tribological performance for practical applications. [ABSTRACT FROM AUTHOR]

In this work, three different coating techniques are compared and their applicability for ultraviolet nanoimprint lithography (UV-NIL) is investigated. As UV-NIL is considered a suitable volume manufacturing production solution for various emerging applications, it is mandatory to consider environmental aspects such as operational energy use and material consumption as well as waste management. In this paper, spin coating, spray coating, and inkjet coating are used to coat both a high refractive index resin (n = 1.9) and a filler-free resin (n = 1.5), respectively. Variable Angle Spectroscopy Ellipsometry (VASE) was used to analyze the influence of different process parameters on the resin thickness as well as to compare the refractive index achieved from each coating technology. Finally, the applicability of the different coating methods for UV-NIL was investigated by imprinting the resin layers with different test structures. For the final imprints, the resolution, the surface roughness, and the pattern fidelity over 25 imprints was assessed using AFM. Finally, a comparison of the resin consumption and the process time was performed for each coating method.

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Yttrium-doped barium zirconate is a commonly used electrolyte material for Protonic Ceramic Fuel Cells (PCFC) due to its high protonic conductivity and high chemical stability. However, it is also known for its poor sinterability and poor grain boundary conductivity. In this work, in response to these issues, reactive magnetron sputtering was strategically chosen as the electrolyte deposition technique. This method allows the creation of a 4 µm tick electrolyte with a dense columnar microstructure. Notably, this technique is not widely utilized in PCFC fabrication. In this study, a complete cell is elaborated without exceeding a sintering temperature of 1350 °C. Tape casting is used for the anode, and spray coating is used for the cathode. The material of interest is yttrium-doped barium zirconate with the formula BaZr0.8Y0.2O3−δ (BZY). The anode consists of a NiO-BZY cermet, while the cathode is composed of BZY and Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSFC) in a 50:50 weight ratio. The electrochemical impedance spectroscopy analysis reveals a global polarization resistance of 0.3 Ω cm2, indicating highly efficient interfaces between electrolytes and electrodes. [ABSTRACT FROM AUTHOR]

Electroluminescence (EL) is an innovative technology in the lighting area. EL devices' main structure consists of a phosphor layer sandwiched between two electrodes. In this work, several alternating-current EL devices were developed by applying a set of sequential layers with combinations of in-house prepared inks and a commercially available ink as the phosphor layer. A flexible polyester textile substrate was functionalized with the inks by spray coating, after knife coating an interfacial layer directly on the surface. A thorough study was carried out on the phosphor layer composition to optimize the EL device performance, more precisely, illuminance intensity and illuminance homogeneity. The developed phosphor layer was composed of zinc sulfide doped with copper (between 30.0 and 38.1 wt%) and diluted by using a diluent at different concentrations (from 28.0 to 35.5 wt%). The best peak illuminance intensity of 61 lux was obtained when the phosphor ink presented a 35.4% ZnS:Cu ratio and was diluted with 33.0% diluent. This study aimed to determine the best formulation of the phosphor layer, which can be highly useful for further developments of EL devices, taking into account different applications in the market. [ABSTRACT FROM AUTHOR]

Ensuring the longevity of wooden constructions depends heavily on the preservation process. However, several traditional preservation methods involving fossil-based compounds have become outdated because they pose a significant risk to the environment and to human health. Therefore, the use of bio-based and bioactive solutions, such as essential oils, has emerged as a more sustainable alternative in protecting wood from biotic attacks. The entrapment of essential oils in polymeric carrier matrices provides protection against oxidation and subsequent degradation or rapid evaporation, which implies the loss of their biocidal effect. In this work, lignin as well as PLGA nanoparticles containing the essential oils from two different thyme species (Thymus capitatus and T. vulgaris) were applied on beech wood samples using spray coating. The prepared coatings were investigated using FTIR imaging, SEM, as well as LSM analysis. Release experiments were conducted to investigate the release behavior of the essential oils from their respective lignin and PLGA carrier materials. The study found that lignin nanoparticles were more effective at trapping and retaining essential oils than PLGA nanoparticles, despite having larger average particle diameters and a more uneven particle size distribution. An analysis of the lignin coatings showed that they formed a uniform layer that covered most of the surface pores. PLGA nanoparticles formed a film-like layer on the cell walls, and after leaching, larger areas of native wood were evident on the wood samples treated with PLGA NPs compared to the ones coated with lignin NPs. The loading capacity and efficiency varied with the type of essential oil, while the release behaviors were similar between the two essential oil types applied in this study. [ABSTRACT FROM AUTHOR]

Paper is a material that is used in many areas of everyday life. The development of paper with special and environmentally friendly properties will contribute to it being used differently than before. In this work, we present a simple, fluorine-free and low-cost method to prepare a multifunctional paper coating with TiO2 nanoparticles modified with 3-aminopropyltriethoxysilane (KH550) and polydimethylsiloxane (PDMS). The effects of the content of precursors such as titanium isopropoxide (TTIP) and PDMS on the wettability, microstructure and durability of the coating were investigated. The result showed that the coated paper exhibited excellent superhydrophobicity and self-cleaning properties with a water contact angle (WCA) of 162.7° and a water sliding angle (WSA) of 2.5°. In addition, the coated paper showed excellent oil/water separation with over 98% after 10 test cycles and high mechanical resistance with an abrasion resistance of 0.26% weight loss after 20 abrasion cycles using the Taber abrasion test (ASTM D4060) with wheel type CS-10. The results of this study indicate a possible method for producing fluorine-free multifunctional paper, which has the potential to expand the application versatility of the material. [ABSTRACT FROM AUTHOR]

In this study, sol–gel derived spray coatings of highly hydrophobic nature consisting of polystyrene (PS) and SiO2 nanoparticles were developed on polished stainless steel 321 (SS) and textured 6061 aluminium (Al) alloy substrates. The micro-structures on the Al surface were created through ultraprecision machining, known as single-point diamond turning (SPDT) machining. The polished SS and micro-structured Al were coated with PS/SiO2 using a spray coating technique by maintaining a pressure of 4–5 kPa, and positioning the nozzle 20–30 cm away from the substrates. The textured surface of Al was characterised using coherent correlational interferometry (CCI). The PS modified SiO2 nanoparticles and their coatings were characterised using Fourier-Transform Infrared Spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM). The resulting coating exhibited a micro-nano hierarchical roughness due to the presence of SiO2 nanoparticles and their fine size clusters. The polished SS surface showed static water contact angles of 93.3° and 143.5° before and after coating, respectively. Similarly, the polished and coated structured Al surface exhibited water contact angles of 85.6° and 144.3° before and after coatings. Such coatings can exhibit a great potential particularly in the field of self-cleaning technologies. [ABSTRACT FROM AUTHOR]

In this work, three different coating techniques are compared and their applicability for ultraviolet nanoimprint lithography (UV-NIL) is investigated. As UV-NIL is considered a suitable volume manufacturing production solution for various emerging applications, it is mandatory to consider environmental aspects such as operational energy use and material consumption as well as waste management. In this paper, spin coating, spray coating, and inkjet coating are used to coat both a high refractive index resin (n = 1.9) and a filler-free resin (n = 1.5), respectively. Variable Angle Spectroscopy Ellipsometry (VASE) was used to analyze the influence of different process parameters on the resin thickness as well as to compare the refractive index achieved from each coating technology. Finally, the applicability of the different coating methods for UV-NIL was investigated by imprinting the resin layers with different test structures. For the final imprints, the resolution, the surface roughness, and the pattern fidelity over 25 imprints was assessed using AFM. Finally, a comparison of the resin consumption and the process time was performed for each coating method. [ABSTRACT FROM AUTHOR]

Thermal spray-applied AlMg alloy coatings are frequently utilized in a variety of technical applications because of great corrosion resistance, and environmental friendliness. In this work, the effect of abrasive spraying parameters on the surface roughness of CT3 steel specimens as well as the effect of the surface roughness on the adhesion strength of Al-Mg alloy spray coating were experimentally investigated. The surface roughness was assessed using a portable roughness gauge. The adhesion strength of the coating was evaluated by the pull-off test, according to the JIS H8664-1977 standard. The experimental findings indicate that air pressure and spraying distance have great impacts on the surface roughness of CT3 steel. The adhesion strength of the Al-Mg coating applied on CT3 steel is found to be almost linearly proportional to the surface roughness. The maximum adhesion strength of 14 MPa was achieved at the highest Rz of about 61 µm.

We reported the comparative studies of the optimization of solution-processable tungsten trioxide (WO3) as a hole transporting layer (HTL) in inverted organic photovoltaics (OPVs) using spin coating, slot-die coating, and spray coating technologies for scaling-up applications. To facilitate the technology's transition into commercial manufacturing, it is necessary to explore the role of scalable technologies for low-cost and efficient device fabrication. We investigated the role of diluting WO3 with isopropanol as an HTL in inverted OPVs to solve the issue of poor wettability of the hydrophobic surface of the PBDB-T: ITIC bulk heterojunction layer. The optimal dilution ratios of WO3 with isopropanol were 1:4, 1:4 and 1:8 with spin coating, slot-die coating and spray coating techniques, respectively. We evaluated the device performance by conducting a current density–voltage (J-V) analysis, incident photon-to-current conversion efficiency (IPCE) measurements, and ultraviolet–visible (UV-Vis) absorbance spectra for various WO3 concentrations. The J-V characteristics revealed that slot-die coating resulted in the highest performance, followed by the spray coating technology. We further investigated the impact of the annealing temperature on device performance for both slot-die- and spray-coated diluted WO3. The highest device performance was achieved at an annealing temperature of 120 °C for both coating technologies. This research offers valuable insights into the scalable fabrication of inverted OPV devices, paving the way for cost-effective and efficient large-scale production. [ABSTRACT FROM AUTHOR]

Smart multi-layer architectures were developed using spray coating of carbon nanotube-rich layers and carbon nanotube-free layers, layer-by-layer, boosting electrochemical charge/discharge kinetics of high mass loading lithium ion battery electrodes. [Display omitted] The ability of lithium ion batteries (LIBs) to provide rapid charging characteristics while retaining a substantial energy storage capacity is of paramount significance for their applicability in portable smart electronic devices. In this research, an effective approach to enhance re-charging rates of LIB cells was developed through incorporating carbon nanotube (CNT) conductivity boosters strategically into Li 4 Ti 5 O 12 (LTO) electrodes. A layer-by-layer spray coating was exploited to manufacture multi-layer architectures that comprise sequential, discrete electrode layers of CNT-rich LTO and CNT-free LTO, aiming at promoting charge transfer kinetics of high mass loading electrodes. Initially, the optimal proportion of a CNT-rich layer and its best location within multi-layer electrode structures were investigated in half-cell configurations. The best performing multi-layer was then paired with a spray-coated LiFePO 4 (LFP) positive electrode in full-cell LIBs, offering attractive power performance of ∼ 1500 W/kg that outperformed conventional LTO || LFP combinations. [ABSTRACT FROM AUTHOR]

Recently, flexible transparent conductive films have received widespread attention as important components in the field of organic electronics. Herein, we propose a method for directly constructing flexible transparent conductive films on curved surfaces using silver nanowires as the primary conductive material with the assistance of ethyl cellulose. The uniform transparent conductive film is produced by spray coating the silver nanowires on the curved surface with a curvature diameter of 5 cm. The average sheet resistance is approximately 18.9 Ω sq–1 with a transparency reaching 92.33%, and the standard deviation of the surface resistance is 1.1 Ω sq–1. The inclusion of ethyl cellulose prevents the aggregation of silver nanowires and allows their even distribution on the film surface, which is crucial for achieving a uniform and stable transparent conductive film. Through the analysis and comparison of different types of cellulose, such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate, and cyanoethyl cellulose, a conclusion has been derived that only cellulose soluble in organic solvents can maintain a homogeneous distribution on the surface of the film without aggregation. Furthermore, changing the magnitude and sign of the curvature did not affect the uniformity of the film. The significant industrial potential of our approach lies in the direct construction of a uniformly transparent silver nanowire network on curved surfaces with applications spanning various fields. Specifically, it can be employed in the realm of electronics, catering to the needs of touchscreens in electronic displays, solar cells, and flexible electronic devices, such as flexible circuit boards. [ABSTRACT FROM AUTHOR]

All-additive-free electrodes were successfully fabricated over 20 × 20 cm2 electrode areas using a layer-by-layer spray coating approach, offering attractive capacity and power capability in a lithium-ion battery configuration. [Display omitted] Polymer binders and carbon conductivity enhancers are inevitably required to make improvements in structural durability and electrochemical performance of lithium-ion battery (LIB) electrodes, although these additive constituents incur weight and volume penalties on the overall battery capacity. Here, additive-free electrode architectures were successfully fabricated over 20 × 20 cm2 electrode areas using a layer-by-layer spray coating approach, with the ultimate goal to boost gravimetric/volumetric electrode capacity and to reduce the total cost of LIB cells. Initially, the binder fraction of spray-coated Li 4 Ti 5 O 12 (LTO) electrodes was reduced progressively, from 40 to 0 wt%. The electrochemical behavior of electrodes was then re-optimized as a proportion of conductivity enhancers within the binder-free electrode decreased to zero. Further, the otherwise identical spray coating process was applied to manufacture LiFePO 4 (LFP) positive electrodes, leading to all-additive-free full-cell LIB configurations with attractive energy density of ∼310 Wh/kg and power performance of ∼1500 W/kg. [ABSTRACT FROM AUTHOR]

The intrinsic water and oil wettability of hydrophobicity and under-water oleophobicity of graphene, synthesized by ultrasonically exfoliating graphite was reversed to superhydrophilicity and under-water superoleophobicity by ultrasonically compositing it with titanium dioxide (TiO2) nanoparticles. The synthesized TiO2 loaded graphene sheets (TiO2@GS) was spray coated on alumina (Al2O3) ceramic substrate (TiO2@GS-coated Al2O3 ceramic membrane) and used as the filtering medium for the separation of oil-in-water emulsion in water passing dead-end oil water filtration system. The water and oil contact angles of TiO2@GS-coated Al2O3 ceramic membrane in air medium were close to zero in air (θWA = θOA = 0°), and the oil contact under the water (θOW) close to 160 ± 1°. The modified water and oil wettability of TiO2@GS-coated Al2O3 ceramic membrane aided not only to achieve the oil–water separation efficiency as high as 99 %, but also to enhance the workable critical pressure that helps to increase the permeate flux J = 150 L.m−2.h−1. Also, the water passing nature of TiO2@GS-coated Al2O3 ceramic membrane, achieved by the modified surface wettability significantly reduced the oil clogging in the pores of the membrane and thereby increased the recyclability of the filtering membrane for the prolonged use.

This study presents the fabrication of LiFePO4 (LFP)-coated carbon fibers (CFs) as a positive electrode component for structural batteries, utilizing a spray coating technique. The successful coating of CFs through this method demonstrated their usefulness as efficient current collectors. The electrodes obtained using this method underwent electrochemical evaluations. Throughout the extended cycling tests at C/7, the maximum specific discharge capacity reached 146 mAh/g, maintaining a 77% capacity retention after 100 cycles. In rate performance assessments at the faster C-rate of 1.5C, the capacity measured 123 mAh/g, with a retention of 96%. The application of spray coating emerges as a promising technique for electrode production in structural batteries, showcasing its potential for optimizing performance in multifunctional energy storage systems.

Graphene nanofilms were deposited by the spray coating method at different concentrations (0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 g) and prepared at 120°C. The prepared nanofilms were characterized in terms of their structural, morphological, optical, and electrical properties. The results confirm the formation of high-purity and high-crystallinity graphene nanofilms with a layered nanosheet morphology. The X-ray diffraction pattern shows the presence of pure graphene with (002) crystal planes. SEM Images show that the intended graphene films are symmetrical with few wrinkles on their surface. The graphene films show semi-transparent behavior with a maximum transmission of 50%. Raman spectroscopy shows that the relative intensity, position, and shape of the G and 2D Raman peaks change with the number of graphene layers. The electrical conductivity increases with temperature, and the conductivity can be further increased depending on the metal or metal oxide functionalization. The electrical conductivity of the graphene film deposited at a concentration of 0.3 g was significantly higher than the values reported for other concentrations. The results of this study suggest that the physical and electrical properties of spray-coated graphene films can be optimized by controlling the solution concentration, which could have potential applications in transparent conductive films.

Herein, we investigate the potential application of a composite consisting of PEDOT:PSS/Graphene, deposited via spray coating on a flexible substrate, as an autonomous conducting film for applications in wearable biosensor devices. The stability of PEDOT:PSS/Graphene is assessed through electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and linear polarization (LP) during exposure to an artificial sweat electrolyte, while scanning electron microscopy (SEM) was employed to investigate the morphological changes in the layer following these. The results indicate that the layers exhibit predominant capacitive behavior in the potential range of −0.3 to 0.7 V vs. Ag/AgCl, with a cut-off frequency of approximately 1 kHz and retain 90% capacity after 500 cycles. Aging under exposure to air for 6 months leads only to a minor increase in impedance, demonstrating potential for storage under non-demanding conditions. However, prolonged exposure (>48 h) to the artificial sweat causes significant degradation, resulting in an impedance increase of over 1 order of magnitude. The observed degradation raises important considerations for the long-term viability of these layers in wearable biosensor applications, prompting the need for additional protective measures during prolonged use. These findings contribute to ongoing efforts to enhance the stability and reliability of conducting materials for biosensors in health care and biotechnology applications.

Spray coating has been exploited to fabricate and tailor the morphologies of various components in thin film composite membranes separately. For the first time, here we exploit this technology to construct and assemble both the selective layer and porous support of a thin-film composite membrane in a single process. In our approach, spray-assisted non-solvent induced phase inversion and interfacial polymerization reduced the time required to fabricate thin-film composite membranes from 3 – 4 days to 1 day and 40 ​min. Our approach did not sacrifice membrane separation performances during desalination of a mixture comprising 2000 ​ppm of NaCl in water at 4 ​bar and room temperature. At these conditions, compared to traditional thin film composite membranes, the water permeance of our spray coated membranes was higher by 35.7 %, reaching 2.32 ​L ​m−2 ​h−1 bar−1, while achieving a NaCl rejection rate of 94.7 %. This demonstrated the feasibility of fabricating thin film composites via spray coating in a single process, potentially reducing fabrication time during scale-up production.

Electrochromism induces reversible changes of coloration in specific organic and inorganic materials through electrical charge/discharge reactions. When processed into thin films, electrochromic metal oxides can be integrated into glazing applications such as displays, rearview mirrors, goggles and, most notably, smart windows in energy-efficient buildings. Over the years, the use of spray coating as a liquid-based approach has been acknowledged for its cost-efficient, high-throughput samples production with a low volume consumption. It represents an interesting alternative to vacuum processes and to other wet methods, suitably responding to the current limitations of electrochromic thin films production by offering improved control over deposition parameters and capacities of up-scaling, together with lowered energetic and economic costs. The present review summarizes the main theoretical and practical aspects of spray coating, notably distinguishing room-temperature methodologies from pyrolysis-based, under heating protocols. The main families of functional electrochromic metal oxides are then screened and discussed, establishing how spray processing can challengingly lead to higher levels of optical contrast, commutation kinetics, coloration efficiency and cycling durability, and how low-toxic and environment-friendly precursors can be favored while sustaining large deposition areas. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the behaviors of bubbles entrained in a film coating during spray coating. Air bubbles that remain in a film coating after diluent evaporation cause coating defects called bubbling defects, including fish-eye and crater defects. In this study, the visualization of a film coating revealed that smaller bubbles in the film shrank slowly and disappeared, while larger bubbles remained. These remaining bubbles grew during the heating process for the drying of the film coating. The shrinking phenomenon was explained using bubble dynamics based on the Young–Laplace equation of a bubble's inner pressure and Henry's law for bubble gas dissolution into the film coating. This shrinking model is often used in studies on microbubble dynamics. The results suggested the importance of avoiding the entrainment of large bubbles during the spraying process and enhancing the release of air bubbles from the film coating's surface through the appropriate usage of defoaming agents. [ABSTRACT FROM AUTHOR]

This study aims to improve the performance of a UV-C disinfection unit by embedding supported photocatalysts in the system. A fiberglass surface mat (FSM) has been coated with TiO2 nanoparticles using a spray coating (SC) technique in the presence of a colloidal silica binder. The ratio between the coating material volume and the support area varied between 0.075 and 0.300 mL/cm2 while maintaining the mass ratio of TiO2 to SiO2 at 1. The spray-coated composite material was dried at 120°C. The results showed the FSM gained mass between 23.63 and 107.27% after SC. The composite materials lost only 1.43–3.62% of their original mass after the stability test. The composite materials showed high methylene blue (MB) removal between 59.25 and 78.86% after 30 min. The study was expanded using tungsten-loaded TiO2 with different tungsten loadings. The results show the FSM composite containing both low-tungsten and high-tungsten-loaded TiO2 is the most promising. Hence, it was tested using a commercial UV-C flow reactor. Simulated water spiked with a binary mixture of MB and methyl orange (MO) and Escherichia coli culture was used as a feed. The MB was readily decolorized at 20% removal, while the MO was not affected at a 5-min residence time at both high and low dye loadings. The E. coli was not detected after passing through the reactor. This study shows embedding photocatalytic fiber in the UV-C disinfection unit improves the performance of the unit, it decolorizes the dye without altering the disinfection of E. coli. [ABSTRACT FROM AUTHOR]

With the increase in the depth of coal mining, the problem of coal spontaneous combustion due to air leakage in the coal mine roadways is becoming increasingly serious. However, traditional cement mortar spray coatings are prone to cracking and poor flexibility, and polyurethane type spray coatings are not flame retardant, they are unable to meet the spraying needs. This paper proposes the preparation of a cement-based flexible spray coating for flame retardant (CFSCF) by modifying the cement-based material with the addition of fly ash, cellulose and emulsion material. The initial dosage ranges of fly ash, cellulose and emulsion material were studied. The effects of different dosages of fly ash, cellulose and emulsion material on the 7-day tensile strength, 14-day tensile strength and 28-day tensile strength were studied, and the optimum ratio of CFSCF was determined by the response surface methodology. The tensile mechanical properties, micromorphology and flame retardant properties of CFSCF with the optimum ratio were studied. The results showed that: the tensile strength of CFSCF reached the maximum at 28 days of maintenance period, 2.55 MPa; the maximum elongation at break was 52.62% at 14 days; the tensile toughness was up to 833.05KJ m−3; when the material was pulled, the two walls of the crack would bond to each other, reflecting the excellent flexibility; the alcohol lamp burning test results showed that there is flame burning time of 0 s, the material leaves the flame extinguished, has good flame retardant properties. [ABSTRACT FROM AUTHOR]

Disposable wearable sensors that ultrathin and conformable to the skin are of significant interest as affordable and easy-to-use devices for short-term recording. This study presents a facile and low-cost method for transferring spray-coated silver nanowire (AgNW) composite films onto human skin using glossy paper (GP) and liquid bandages (LB). Due to the moderately hydrophobic and rough surface of the GP, the ultrathin AgNWs composite film (~200 nm) was easily transferred onto human skin. The AgNW composite films conformally attached to the skin when applied with a LB, resulting in the stable and continuous recording of wearable electrophysiological signals, including electromyogram (EMG), electrocardiogram (ECG), and electrooculogram (EOG). The volatile LB, deposited on the skin via spray coating, promoted rapid adhesion of the transferred AgNW composite films, ensuring stability to the AgNWs in external environments. The AgNWs composite supported with the LB film exhibited high water vapor breathability (~28 gm−2h−1), which can avoid the accumulation of sweat at the skin–sensor interface. This approach facilitates the creation of rapid, low-cost, and disposable tattoo-like sensors that are practical for extended use. [ABSTRACT FROM AUTHOR]

Yttrium-doped barium zirconate is a commonly used electrolyte material for Protonic Ceramic Fuel Cells (PCFC) due to its high protonic conductivity and high chemical stability. However, it is also known for its poor sinterability and poor grain boundary conductivity. In this work, in response to these issues, reactive magnetron sputtering was strategically chosen as the electrolyte deposition technique. This method allows the creation of a 4 µm tick electrolyte with a dense columnar microstructure. Notably, this technique is not widely utilized in PCFC fabrication. In this study, a complete cell is elaborated without exceeding a sintering temperature of 1350 °C. Tape casting is used for the anode, and spray coating is used for the cathode. The material of interest is yttrium-doped barium zirconate with the formula BaZr0.8Y0.2O3−δ (BZY). The anode consists of a NiO-BZY cermet, while the cathode is composed of BZY and Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSFC) in a 50:50 weight ratio. The electrochemical impedance spectroscopy analysis reveals a global polarization resistance of 0.3 Ω cm2, indicating highly efficient interfaces between electrolytes and electrodes.

Ensuring the longevity of wooden constructions depends heavily on the preservation process. However, several traditional preservation methods involving fossil-based compounds have become outdated because they pose a significant risk to the environment and to human health. Therefore, the use of bio-based and bioactive solutions, such as essential oils, has emerged as a more sustainable alternative in protecting wood from biotic attacks. The entrapment of essential oils in polymeric carrier matrices provides protection against oxidation and subsequent degradation or rapid evaporation, which implies the loss of their biocidal effect. In this work, lignin as well as PLGA nanoparticles containing the essential oils from two different thyme species (Thymus capitatus and T. vulgaris) were applied on beech wood samples using spray coating. The prepared coatings were investigated using FTIR imaging, SEM, as well as LSM analysis. Release experiments were conducted to investigate the release behavior of the essential oils from their respective lignin and PLGA carrier materials. The study found that lignin nanoparticles were more effective at trapping and retaining essential oils than PLGA nanoparticles, despite having larger average particle diameters and a more uneven particle size distribution. An analysis of the lignin coatings showed that they formed a uniform layer that covered most of the surface pores. PLGA nanoparticles formed a film-like layer on the cell walls, and after leaching, larger areas of native wood were evident on the wood samples treated with PLGA NPs compared to the ones coated with lignin NPs. The loading capacity and efficiency varied with the type of essential oil, while the release behaviors were similar between the two essential oil types applied in this study.

Using cocrystals has emerged as a promising strategy to improve the physicochemical properties of active pharmaceutical ingredients (APIs) by forming a new crystalline phase from two or more components. Particle size and morphology control are key quality attributes for cocrystal medicinal products. The needle-shaped morphology is often considered high-risk and complex in the manufacture of solid dosage forms. Cocrystal particle engineering requires advanced methodologies to ensure high-purity cocrystals with improved solubility and bioavailability and with optimal crystal habit for industrial manufacturing. In this study, 3D-printed microfluidic chips were used to control the cocrystal habit and polymorphism of the sulfadimidine (SDM): 4-aminosalicylic acid (4ASA) cocrystal. The addition of PVP in the aqueous phase during mixing resulted in a high-purity cocrystal (with no traces of the individual components), while it also inhibited the growth of needle-shaped crystals. When mixtures were prepared at the macroscale, PVP was not able to control the crystal habit and impurities of individual mixture components remained, indicating that the microfluidic device allowed for a more homogenous and rapid mixing process controlled by the flow rate and the high surface-to-volume ratios of the microchannels. Continuous manufacturing of SDM:4ASA cocrystals coated on beads was successfully implemented when the microfluidic chip was connected in line to a fluidized bed, allowing cocrystal formulation generation by mixing, coating, and drying in a single step. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA)-based contact-active antimicrobial surfaces were successfully fabricated via the spray coating method. For this purpose, firstly two separate antimicrobial polymers were synthesized by introducing alkyne functionalized quaternary ammonium salt into clickable copolymer containing 30 mol% and 5 mol% of quaternary ammonium salt on their backbones. Then, these synthesized polymers were applied to coat one surface of the neat PLA films (PLA/PEG, 90/10) at the rate of 5, 15, and 25 times, respectively. Afterward, the biocidal effect of these films was considered against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria by the way of contact-active method. It was observed that the films coated with polymer containing 30 mol% of quaternary ammonium salt (QAS), even at the lowest coating amount, showed a considerably active antimicrobial property against both bacteria. The thermal, mechanical, and barrier properties of coated films were also investigated. In addition, a cytotoxicity test was performed, and it was found that the PLA film was nontoxic when it was coated with polymer containing 5 mol% of quaternary ammonium salt, even at a high coating amount. For a polymer containing 30 mol% of quaternary ammonium salt on its backbone, it was necessary to coat the films at a low rate for acceptable cytotoxicity. In conclusion, due to the contact-active behavior of covalently attached antimicrobial agents, high antibacterial activity, suitable mechanical properties, and acceptable cytocompatibility, these antimicrobial surfaces can be considered as a potential candidate for bio-based materials. [ABSTRACT FROM AUTHOR]

Cellulose nanofibre (CNF) is the sustainable nanomaterial used for developing high-performance barrier materials that are renewable, recyclable, and biodegradable. The CNF film has very low oxygen permeability; however, its water vapor permeability is significantly higher than that of conventional packaging plastics. The fabrication method influences their barrier properties of the film. A spray-coating CNF on a stainless-steel plate was developed to form a compact film with two unique surfaces, namely a smooth layer on the base side and rough layer on the free side. It improves both the ease of preparation of the film and reduces the water vapour permeability via tailoring the basis weight and thickness of the film through simple adjusting CNF content in the suspension. The air permanence of the film from 1.0 wt.% to 2.0 wt.% CNF suspension is less than 0.003 µm/Pa·S confirming that is an impermeable film and proves a good packaging material. SEM, optical profilometry, and AFM revealed that the spray-coated surface was smooth and glossy. For sprayed CNF films with basis weight between 86.26 ± 13.61 and 155.85 ± 18.01 g/m2, WVP were ranged from 6.99 ± 1.17 × 10−11 to 4.19 ± 1.45 × 10−11 g/m·Pa·S. In comparison, the WVP of 100 g/m2 vacuum filtered CNF film was 5.50 ± 0.84 × 10−11 g/m·Pa·S, spray-coated film (of 96.6 g/m2) also show similar permeability at around 5.34 ± 0.603 × 10−11 g/m·Pa·S. The best performance was achieved with spraying of 2.0 wt.% CNF and a water vapour permeability of 3.91 × 10−11 g/m·s·Pa. Spray coated CNF film is impermeable against air and water vapour and a potential alternative to synthetic plastics.

We report process improvements for the fabrication of single-walled carbon nanotube ethylene-vinyl acetate transparent conductive films. CNT:EVA films demonstrate high resilience against folding and can replace the external dopant in a spiro-OMeTAD based hole selective contact of n-i-p perovskite solar cells achieving a steady-state efficiency of 16.3%. The adapted process is fully scalable, and compared to previous reports (Mazzotta et al., 2018) lowers the material cost dramatically and improves DC to optical conductivity ratio by two orders of magnitude to σdc/σop=3.6for pristine and σdc/σop=15for chemically doped films. We analyse the microstructure of our films via small angle neutron scattering and find a positive correlation between the long range packing density of the CNT:EVA films and the σdc/σopperformance. Increasing monomer ratio and chain length of the EVA polymer improves resilience against bending strain, whereas no significant effect on the CNT wrapping and electrical conductivity of resulting films is found.

In this work, the deposition of β-Ga2O3 microstructures and thin films was performed with Ga(NO3)3 solutions by ultrasonic nebulization and spray coating as low-cost techniques. By changing the deposition parameters, the shape of β-Ga2O3 microstructures was controlled. Micro-spheres were obtained by ultrasonic nebulization. Micro-flakes and vortices were fabricated by spray coating aqueous concentrated and diluted precursor solutions, respectively. Roundish flakes were achieved from water–ethanol mixtures, which were rolled up into tubes by increasing the number of deposition cycles. Increasing the ethanol-to-water ratio allows continuous thin films at an optimal Ga(NO3)3 concentration of 0.15 M and a substrate temperature of 190 °C to be formed. The monoclinic β-Ga2O3 phase was achieved by thermal annealing at 1000 °C in an ambient atmosphere. Scanning electronic microscopy (SEM), X-ray diffraction (XRD), and UV-Raman spectroscopy were employed to characterize these microstructures. In the XRD study, in addition to the phase information, the residual stress values were determined using the sin2(ψ) method. Raman spectroscopy confirms that the β-Ga2O3 phase and relative shifts of the Raman modes of the different microstructures can partially be assigned to residual stress. The high-frequency Raman modes proved to be more sensitive to shifting and broadening than the low-frequency Raman modes. [ABSTRACT FROM AUTHOR]

With the rapid advancement in THz technology and continuously increasing number of electrical and electronic devices in this frequency band, highly efficient and functional THz shielding materials are required to ensure the intended working of these devices. Polymeric composites of hybrid nano-fillers including CNFs and magnetic nanoparticles possess distinctive capability of providing high shielding efficiency primarily absorptive in nature with field functional properties. In this article, lightweight polymeric nanocomposite coatings of continuous carbon nanofibers and magnetite (Fe3O4), as potential shielding material for the THz frequency band, have been prepared using a cost-effective conventional air-spray coating method. The obtained results are quite exclusive, as the sample with 40 wt % Fe3O4 outperforms at a very low thickness value of 540 μm, showing the highest SE value of ∼60 dB. These results are superior compared to the results obtained from most of the contemporary polymer composite materials, which usually provide good shielding at high thickness values in the mm range. Also, this study establishes that shielding performance of the polymeric hybrid nanocomposites (Fe3O4 + CNFs) is substantially better than a single nanocomposite CNF filler previously synthesized and characterized through the same approach. [ABSTRACT FROM AUTHOR]

Photochromism is an interesting method to enhance the anticounterfeiting activity of commercial products. Polyester fibers have been significant polymers for a variety of applications; however, they have been known to resist staining due to the absence of reactive dyeing site on their fibrous surface. Herein, we present recycled nonwoven polyester immobilized with rare‐earth activated aluminate nanoparticles for anticounterfeiting applications. Using the heterogeneous precipitation method, the lanthanide‐doped aluminate pigment was firstly coated with silica to give phosphor‐encapsulated within silica nanoparticles (Silica@Phosphor). The produced Silica@Phosphor particles were mixed with an adhesive binder in an aqueous medium, which was then spray‐coated directly onto plasma‐pretreated nonwoven polyester fabric. The fibrous composite demonstrated ultraviolet‐induced photochromism. Both phosphor and Silica@Phosphor morphologies demonstrated particle diameter of 4–12 and 90–105 nm, respectively. Various techniques were utilized to examine both morphologies and compositions of the photochromic nonwoven fabrics. The antibacterial activity, cytotoxicity, comfortability, colorfastness, and ultraviolet shielding of the prepared polyesters immobilized with Silica@Phosphor were also reported. The luminescent fabrics demonstrated two emission wavelengths at 435 and 514 nm (green) upon excitation at 369 nm (colorless). The nonwoven fabrics showed an enhanced superhydrophobicity as an improved contact angle up to 129.9° was detected upon increasing the Silica@Phosphor ratio. [ABSTRACT FROM AUTHOR]

MXenes constitute a new class of two-dimensional materials and have received considerable attention in the past decade from researchers in a wide variety of fields. In this study, we showed that the rheological properties of the concentrated (50 wt%) colloidal suspensions of the MXene sediment can be easily controlled by various water-soluble polymers to facilitate their solution processing in practical applications. The viscosity of the initially gelled polymer-free suspension at low shear rates was reduced by several orders of magnitudes by adding nonionic, anionic, and cationic polymers that can adsorb on the particle surface. The cationic poly(diallyldimethylammonium chloride) (PDDA) afforded the highest reduction in viscosity, attributed to the decrease in the undesirable face-to-edge electrostatic attraction between the MXenes. The PDDA-doped concentrated suspensions exhibited remarkably low viscosities and elastic moduli and thus can be applied to spray coating process without clogging even at high particle loadings. [ABSTRACT FROM AUTHOR]

Metallic additive manufacturing is expeditiously gaining attention in advanced industries for manufacturing intricate structures for customized applications. However, the inadequate surface quality has inspired the inception of metallic coatings through additive manufacturing methods. This work presents a brief review of the different genres of metallic coatings adapted by industries through additive manufacturing technologies. The methodologies are classified according to the type of allied energies used in the process, such as direct energy deposition, binder jetting, powder bed fusion, hot spray coatings, sheet lamination, etc. Each method is described in detail and supported by relevant literature. The paper also includes the needs, applications, and challenges involved in each process. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) paint with a hydrophobic surface can be easily fouled. In this study, hydrophilic silica nanoparticles and hydrophobic silane were used to modify the surface hydrophobicity that affects the fouling properties of PU paint. Blending silica nanoparticles followed by silane modification only resulted in a slight change in surface morphology and water contact angle. However, the fouling test using kaolinite slurry containing dye showed discouraging results when perfluorooctyltriethoxy silane was used to modify the PU coating blended with silica. The fouled area of this coating increased to 98.80%, compared to the unmodified PU coating, with a fouled area of 30.42%. Although the PU coating blended with silica nanoparticles did not show a significant change in surface morphology and water contact angle without silane modification, the fouled area was reduced to 3.37%. Surface chemistry could be the significant factor that affects the antifouling properties of PU coating. PU coatings were also coated with silica nanoparticles dispersed in different solvents using the dual-layer coating method. The surface roughness was significantly improved by spray-coated silica nanoparticles on PU coatings. The ethanol solvent increased the surface hydrophilicity significantly, and a water contact angle of 18.04° was attained. Both tetrahydrofuran (THF) and paint thinner allowed the adhesion of silica nanoparticles on PU coatings sufficiently, but the excellent solubility of PU in THF caused the embedment of silica nanoparticles. The surface roughness of the PU coating modified using silica nanoparticles in THF was lower than the PU coating modified using silica nanoparticles in paint thinner. The latter coating not only attained a superhydrophobic surface with a water contact angle of 152.71°, but also achieved an antifouling surface with a fouled area as low as 0.06%. [ABSTRACT FROM AUTHOR]

Cellulose nanofibre (CNF) is the sustainable nanomaterial used for developing high-performance barrier materials that are renewable, recyclable, and biodegradable. The CNF film has very low oxygen permeability; however, its water vapor permeability is significantly higher than that of conventional packaging plastics. The fabrication method influences their barrier properties of the film. A spray-coating CNF on a stainless-steel plate was developed to form a compact film with two unique surfaces, namely a smooth layer on the base side and rough layer on the free side. It improves both the ease of preparation of the film and reduces the water vapour permeability via tailoring the basis weight and thickness of the film through simple adjusting CNF content in the suspension. The air permanence of the film from 1.0 wt.% to 2.0 wt.% CNF suspension is less than 0.003 µm/Pa·S confirming that is an impermeable film and proves a good packaging material. SEM, optical profilometry, and AFM revealed that the spray-coated surface was smooth and glossy. For sprayed CNF films with basis weight between 86.26 ± 13.61 and 155.85 ± 18.01 g/m2, WVP were ranged from 6.99 ± 1.17 × 10−11 to 4.19 ± 1.45 × 10−11 g/m·Pa·S. In comparison, the WVP of 100 g/m2 vacuum filtered CNF film was 5.50 ± 0.84 × 10−11 g/m·Pa·S, spray-coated film (of 96.6 g/m2) also show similar permeability at around 5.34 ± 0.603 × 10−11 g/m·Pa·S. The best performance was achieved with spraying of 2.0 wt.% CNF and a water vapour permeability of 3.91 × 10−11 g/m·s·Pa. Spray coated CNF film is impermeable against air and water vapour and a potential alternative to synthetic plastics. [ABSTRACT FROM AUTHOR]

We reported the comparative studies of the optimization of solution-processable tungsten trioxide (WO3) as a hole transporting layer (HTL) in inverted organic photovoltaics (OPVs) using spin coating, slot-die coating, and spray coating technologies for scaling-up applications. To facilitate the technology’s transition into commercial manufacturing, it is necessary to explore the role of scalable technologies for low-cost and efficient device fabrication. We investigated the role of diluting WO3 with isopropanol as an HTL in inverted OPVs to solve the issue of poor wettability of the hydrophobic surface of the PBDB-T: ITIC bulk heterojunction layer. The optimal dilution ratios of WO3 with isopropanol were 1:4, 1:4 and 1:8 with spin coating, slot-die coating and spray coating techniques, respectively. We evaluated the device performance by conducting a current density–voltage (J-V) analysis, incident photon-to-current conversion efficiency (IPCE) measurements, and ultraviolet–visible (UV-Vis) absorbance spectra for various WO3 concentrations. The J-V characteristics revealed that slot-die coating resulted in the highest performance, followed by the spray coating technology. We further investigated the impact of the annealing temperature on device performance for both slot-die- and spray-coated diluted WO3. The highest device performance was achieved at an annealing temperature of 120 °C for both coating technologies. This research offers valuable insights into the scalable fabrication of inverted OPV devices, paving the way for cost-effective and efficient large-scale production.