Search

In this work, white Portland cement (WPC) based composite coatings consisting of WPC, building glue, phase change microcapsules, TiO 2 particles, polymethylhydrosiloxane, and SiO 2 particles were developed via a brushing method. After adjusting the variety and content of additives, the optimized WPC coating (PCM 30 S/WPCM) exhibits a phase transition temperature of 35 °C, solar reflectivity of 0.764, contact angle of 157.6°, and rolling angle of 7.1°. The coating shows stable superhydrophobicity in the corrosion test, mechanical abrasion test, ultraviolet (UV) aging experiment, and temperature fluctuation experiment. In addition, the superhydrophobic WPC composite coating exhibits a significant cooling effect of 8.5 °C under simulated solar radiation. Furthermore, the phase change coating can also prevent large fluctuation of coating surface temperature through phase change function, so as to improve building comfort. The simulation analysis indicates that the energy saving rate of the superhydrophobic phase change coating is the highest in Guangzhou, China, which is 23.2%. [Display omitted] • The coating is prepared using cheap industrial raw materials and simple methods. • The coating exhibits self-cleaning, solar reflective, and phase change properties. • The coating has excellent weather resistance, acid resistance and mechanical stability. • The coating can reduce the total energy consumption of buildings in Guangzhou, China. • The coating can reduce the temperature fluctuation of building environment and improve building comfort. [ABSTRACT FROM AUTHOR]

We present the excellent anti-icing performance for a superhydrophobic coating surface based on ZnO/polydimethylsiloxane (ZnO/PDMS) composite. The superhydrophobic ZnO/PDMS coating surface was prepared by a facile solution mixing, drop coating, room-temperature curing and surface abrading procedure. The superhydrophobic ZnO/PDMS composite coating possesses a water contact angle of 159.5° and a water sliding angle of 8.3° at room temperature (5 °C). The anti-icing properties of the superhydrophobic coating were investigated by continuously dropping cold-water droplets (about 0 °C) onto the pre-cooled surface using a home-made apparatus. The sample was placed at different tilting angle (0° and 10°) and pre-cooled to various temperatures (−5, −10 and −15 °C) prior to measure. The pure Al surface was also studied for comparison. It was found that icing accretion on the surface could be reduced apparently because the water droplets merged together and slid away from the superhydrophobic surface at all of the measuring temperatures when the surface is horizontally placed. In addition, water droplet slid away completely from the superhydrophobic surface at −5 and −10 °C when the surface is tilted at 10°, which demonstrates its excellent anti-icing properties at these temperatures. When the temperature decreased to −15 °C, though ice accretion on the tilted superhydrophobic coating surface could not be avoided absolutely, the amount of ice formed on the surface is very small, which indicated that the coating surface with superhydrophobicity could significantly reduce ice accumulation on the surface at very low temperature (−15 °C). Importantly, the sample is also stable against repeated icing/deicing cycles. More meaningfully, once the superhydrophobic surface is damaged, it can be repaired easily and rapidly. [ABSTRACT FROM AUTHOR]

• FD and PC based bulk composites and superhydrophobic coatings were prepared. • The FD/PC composite with FD content of 10% have relatively high mechanical strength. • The superhydrophobic coating was prepared using a simple brushing method. • The superhydrophobic coatings exhibited mechanical robustness and easy repairability. • The water absorption of the coating modified FD/PC composite is greatly reduced. In this study, Found dust (FD) and Portland cement (PC) based bulk composites and superhydrophobic coatings were prepared to utilize the solid waste FD and improve the water permeability. First, the compositions, structures, pore parameters, and mechanical properties of the FD/PC composites were tested and analyzed, indicating that the mechanical strength of the FD/PC composites decreased with increasing FD content. The flexural compressive strength and compressive strength of the FD/PC composites with an FD content of 10% reduced by only 8.5% and 9.8%, respectively, compared to that of the neat hardened cement paste (HCP). At greater than 10% FD content, the mechanical strength of the FD/PC composite material drastically reduced. Second, the FD and PC based superhydrophobic coatings were prepared using a simple brush-coating method by introducing polydimethylsiloxane as a hydrophobic admixture. The composite coating exhibits superhydrophobicity after stored at room temperature for 24 h. In addition, the mechanical robustness of the FD and PC composite based coating is excellent in the abrasion and peeling test and was further improved by double-layer coating method. Particularly, the superhydrophobic coating can be easily repaired after getting damaged. Furthermore, the water absorption of the superhydrophobic coating modified FD/PC composites reduced by more than 76% in comparison with that of the uncoated FD/PC composites. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling (PDRC) is a cooling technology with no energy consumption and no pollution generation. It emits self-generated heat to outer space using thermal radiation, thus reducing its temperature. Radiative cooling technology aims to the energy consumption problem of buildings and environmental pollution caused by the use of Freon in compressor air conditioners. Many kinds of radiative cooling coatings have been attempted, but the cost and large-scale practical application have been challenging. This work prepared a composite coating with a radiative cooling function using calcined kaolin (CK) powder and waterborne fluorocarbon (WF). The inexpensive CK has a wide particle size distribution and exhibits high solar reflectivity (RS) and infrared emissivity (EIR). The excellent adhesion and chemical stability of waterborne fluorocarbon (WF) provides a good guarantee for the practical use of the coating. As a result, the CK/WF coating achieves an RS of 91% and an EIR of 95% in the transparent atmospheric window (ATW) of 8–13 µm. The coating demonstrated a temperature decline of 3.8 °C under direct sunlight in the field. The coating meets the conditions for large-scale applications. When used as a roofing material for simulation, it can save up to 30% of energy consumption throughout the year. Overall, the CK/WF coating has outstanding energy saving and pollution reduction performance, which will further advance the radiant cooling material into real-world applications. [Display omitted] • The RS and EIR of Calcined kaolin/ water-based fluoro olefin vinyl ether copolymer (CK/WF) coating reached 91% and 95%. • The low powder content of the CK/WF coating provides high adhesion force. • Cheap CK powder provides a new idea to reduce the cost of radiation-cooling coating. • Under direct sunlight, the CK/WF coating can achieve a cooling effect of − 3.8 °C. • EnergyPlus simulations show that the coating could save 10% of energy consumption in most areas of China. [ABSTRACT FROM AUTHOR]

Endowing the building exterior wall with superhydrophobicity and radiation cooling function can not only achieve building energy conservation, but also significantly reduce the cost of manual cleaning, so as to ensure the efficiency and durability of the radiant cooling function of the building exterior wall. However, it is still a challenging work to make coatings (paint films) with the above two functions on the surface of large external walls. Herein, we have developed a polyvinylidene fluoride/polydimethylsiloxane (PVDF/PDMS) composite coating composed of PVDF particles and PDMS binder, which is prepared by one-step brushing method. It exhibits solar reflectivity of 90.6%, infrared emissivity of 98.1%, contact angle of 158.2° and rolling angle of 7.9°. The PVDF/PDMS coating exhibits a radiative cooling temperature of 4.93 °C under direct solar irradiation. Importantly, both the DRC function and the superhydrophobicity of the PVDF/PDMS film exhibit excellent weatherability during the one-year outdoor weather resistance test and remarkable mechanical durability in sandpaper abrasion and sand impact tests. Therefore, the long-term self-cleaning DRC paint developed in this work has a potential application prospect in the field of building exterior wall or roof. [Display omitted] • The superhydrophobic PVDF/PDMS paint exhibits high solar reflectivity and high infrared emmisivity simultaneously. • The PVDF/PDMS paint can be simply painted on various substrates in large-scale. • Both the self-cleaning property and radiative cooling performance of the paint are weather-resistant and mechanical robust. [ABSTRACT FROM AUTHOR]

Paraloid B72, composed of an ethyl methacrylate (70%) and methyl acrylate (30%) copolymer, is widely used in the field of cultural relics protection due to its transparency, durability, and nonyellowing. However, B72 is hydrophilic and the water resistance should be enhanced. Herein, as a further study of the pioneer research by Ntelia et al. [1], transparent superhydrophobic coating was prepared and the durability as well as the protection against moisture will be studied. B72 was mixed with the hydrophobic nanoparticles of SiO 2 in xylene and a transparent and superhydrophobic coating was then obtained by spraying onto the substrate of fabric, paper and wood. The fraction of SiO 2 in the mixture was optimized to be 2 wt% by taking hydrophobicity, air permeability, transparency, and ultraviolet transmittance into consideration. The optimal coating presented a continuous porous network surface structure with the maximum contact angle of 165° and the minimum sliding angle of 6°. Average transmittance in visible and ultraviolet light range for the composite coating on glass was 72.57% and 19.46%, versus 82.81% and 32.26% for B72, respectively. BS2 coating permeability for different substrates are less than 10%. Contact angle remained above 150° after 4 h of contact with liquids with a pH of 1–13. Water contact angle on the simulated paper relics after exposure to a hot humid (60 °C, 85 – 90 RH%) atmosphere for 5 days remained above 150°. In addition, BS2 coating showed good UV resistance after 10 days of UV light irradiation. All these data demonstrated that such a coating may find potential application in the relic protection due to its superhydrophobicity, breathability, transparency, ultraviolet protection, and durability. [Display omitted] [ABSTRACT FROM AUTHOR]

This study aims to protect murals by a translucent and superhydrophobic coating using a one-step spraying process, which offers simplicity, efficiency, and cost-effectiveness, while preserving the mural's visual appeal and safeguarding against moisture. Despite numerous advancements in cultural relic conservation, the application of super-hydrophobic coatings for mural preservation remains a novel approach. The coating consists of acrylic resin (Paraloid B72), nano-silica, and polydimethylsiloxane (PDMS). The optimal amounts of silica and PDMS were 3 g each in a basal solution containing 12 g of acrylic resin dissolved in 88 mL of xylene. The resulting composite coating displayed exceptional water repellency, as indicated by a contact angle of 165.5° and a rolling angle of approx. 7°. As a result, the moisture absorption of the mural decreased significantly from ∼53% to ∼5% after the application of the superhydrophobic coating. The coating had minimal impact on the water vapor permeability of the mural, with a ca. 13% decline rate. The coating is translucent with a visible transmittance of approximately 60%. Therefore, the coated mural maintains its original appearance with minimal changes. Furthermore, the superhydrophobic properties of the coating remain intact even after undergoing five cycles of high-low temperature fatigue tests, 196 hours of ultraviolet irradiation, or seven cycles of sand impacting. [Display omitted] • Preparation of a superhydrophobic coating via a one-step spray method. • Significantly reduces moisture absorption of mural via superhydrophobicity. • Breathable with an air permeability decline rate of only 13%. • Translucent with a minimal color difference after application. • Durable against chemical/mechanical exposure and UV radiation tests. [ABSTRACT FROM AUTHOR]

The slippery liquid-infused porous surface (SLIPS) inspired by the Nepenthes plants has received great attention due to the excellent water-repellency with ultra-low sliding angle. However, the practical application of SLIPS is restricted greatly due to the inevitable loss of lubricant trapped by the micro/nanostructures and the adverse environmental impact of the fluorinated lubricant. Herein, we report a simple and efficient strategy to form a solid slippery coating without loss of lubricant. A commercially available coating with the nominal active constituent of polysilazane (PSZ) was used as the matrix and was slippery with the water sliding angle of approx. 25°. To enhance the water repellency, α, ω- hydroxy silicone oil (HSO) was added into the PSZ solution and the sliding angle of the cured composite coating decreased to approx. 7.0°. The chemical interaction between the Si-H / Si-N bonds of PSZ and the -OH group of HSO produced strong inter-molecular attraction. Acrylic resin was further added to strengthen the overall integrity of the coating and the so-obtained composite coating was durable with no loss of lubricant. Moreover, the curing of PSZ at room temperature was accelerated greatly by HSO from longer than one week to less than one day due to the above-mentioned chemical interactions between the Si-H / Si-N bonds and the -OH group. The solid slippery coating showed promising potential in preventing ice adhesion and anti-sticking to adhesive paper due to its low adhesion properties. [Display omitted] • Solid slippery coating was achieved by curing at room temperature. • More durable as compared with the slippery liquid-infused porous surface. • Hydroxy silicone played multiple roles as curing accelerator and lubricant. • Can be used for anti-icing and anti-sticking. [ABSTRACT FROM AUTHOR]

• Coating proposed for anti-icing and de-icing using photothermal and superhydrophobic benefits. • Prussian blue enables the formation of micro/nano structures, crucial for superhydrophobicity. • Prussian blue acts as a crosslinking agent, preventing cracking and ensuring durability. • Prussian blue enhances photothermal effect by acting as a light absorber. Ice accumulation has caused significant losses, making it necessary to find effective anti-icing and de-icing solutions. In this paper, we propose a composite coating that combines the benefits of a photothermal and superhydrophobic surface. This innovative coating incorporates Prussian blue particles and silica nanoparticles into a polytetrafluoroethylene dispersion. Prussian blue in the composite coating plays a crucial role in its effectiveness. Firstly, it facilitates the formation of dual-scale micro/nano structures, which are essential for achieving superhydrophobicity. Additionally, it acts as a crosslinking agent, preventing the coating from cracking and ensuring its durability. Lastly, it enhances the photo thermal effect of the coating by acting as a light absorber. [ABSTRACT FROM AUTHOR]

• Superhydrophobic, wrinkle resistant fabric was obtained by Simple Soaking Method. • SiO 2 was adhered to the fabric by epoxy for micro-nano roughness. • The high wrinkle-recovering of the fabric was attributed to the shape memory of epoxy. Self-cleaning and crease-recovering are of special significance to increase the value of the fabrics. To endow the common cotton fabric with such multi-functionalities, a composite coating of shape memory epoxy resin / silica nanoparticles was proposed herein. The so-finished fabric exhibited good superhydrophobic nature with contact angle of 155.8° and crease self-restoring property with a heating wrinkle recovery angle of 144.1°. Moreover, the so-finished fabric possessed excellent stability under mechanical abrasion against sand paper, and ultrasonic vibration in ethanol. [ABSTRACT FROM AUTHOR]