A high-radiation-resistant cooling window with a hierarchical metamaterial structure coating and a preparation method thereof

Abstract

The application provides an anti-high-radiation cooling window with a hierarchical metamaterial structure coating and a preparation method thereof. The anti-high-radiation cooling window comprises at least one hierarchical metamaterial structure coating integrated on the surface of a window frame or a louver blade, and the anti-high-radiation cooling window with the hierarchical metamaterial structure coating is formed. The hierarchical metamaterial structure coating comprises a light functional layer designed by hierarchical micro-nano structures and a cover hydrophobic protective layer, can effectively and accurately control the reflection path of solar radiation in the coating, and realizes the high-efficiency anti-high-radiation performance of the cooling window. The anti-high-radiation cooling window can realize sustainable and efficient passive cooling in a high-solar-radiation environment. The anti-high-radiation cooling window can be applied to building windows such as office buildings and sentry boxes, vehicle windows such as cars, trains, airplanes and ships, and special equipment windows such as space cabins, and significantly improves the indoor thermal comfort of buildings, vehicles and special equipment in a high-solar-radiation environment.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a high-radiation-resistant cooling window with a graded metamaterial structure coating, its preparation method, and its application. Background Technology

[0002] As people's living standards continue to improve, their demands for living environments are increasing, and intelligent environmental control technology is becoming increasingly integrated into people's daily lives. Indoor light intensity and temperature are two important indicators that determine the comfort level of a building environment. Windows, as channels for direct light and heat exchange between a building and the outside environment, are an effective way to regulate the heat radiation exchange between the interior and the environment. Therefore, windows have always been a key design focus in architectural design and interior decoration. Currently, curtains, blinds, drapes, and venetian blinds are the most common window components. However, traditional window fixtures only control the isolation and connection between the interior and the outside environment through simple opening and closing actions, and do not have the ability to regulate the reception of solar radiation and the emission of their own heat radiation, thus failing to achieve real-time control of indoor temperature.

[0003] Existing technology CN202110780815.6 discloses a cooling product consisting of a full solar spectrum high reflectivity film with micro-nano pores formed by multiple micro-nano fibers intertwined and a substrate material. The full solar spectrum high reflectivity film is then composited onto the cooling base fabric to obtain a full solar spectrum high reflectivity fabric. Existing technology CN202311450217.8 also discloses a method for preparing and applying passive cooling photothermal control fibers and fabrics. This method utilizes the difference between different refractive indices within the fibers to achieve high reflectivity in the solar radiation band through the micro-nano optical structure design of the fibers. Combined with the imaginary part of the refractive index of the fiber material and the introduced nano-medium particles, it achieves high emission in the entire mid-infrared band. This enables the passive cooling photothermal control fibers and fabrics to achieve broad-spectrum selective control in the solar radiation band and the mid-infrared band, ultimately achieving a highly efficient passive cooling effect for the human body in outdoor high-temperature environments. Patent CN 116104253A discloses a heat-insulating color steel tile and its preparation method. It solves the problem of high temperature of heat-insulating color steel plate by stacking multiple anti-corrosion layers, waterproof layers, aerogel layers and radiation cooling layers. However, its structure is diverse, the preparation process is relatively complicated, it requires the use of multiple types of solvents and has a long curing cycle, making it unsuitable for application on the surface of window building materials.

[0004] The method of controlling spectral performance by adding optical particles to a polymer matrix coated on a window surface has performance limitations. Achieving better spectral characteristics requires high-quality material properties, and blindly altering the material composition can easily damage its performance. Therefore, seeking a new method to maximize the performance of cooling materials without changing their composition or properties is of significant invention value. However, previous techniques often only involved processing and combining materials without fine-tuning them, resulting in the inability to achieve optimal optical performance when using similar raw materials. Summary of the Invention

[0005] In view of this, a high-radiation-resistant cooling window with a hierarchical metamaterial structure coating is proposed, along with its preparation method and application. By integrating the hierarchical metamaterial structure coating onto the window frame and the surface of the louver blades, a high-radiation-resistant cooling window with a hierarchical metamaterial structure coating is constructed. This significantly reduces the absorption of external solar radiation heat by the window and emits its own heat into the environment through strong mid-infrared radiation, thereby solving the problem of weak thermal regulation capability of windows in existing technologies.

[0006] The present invention provides a high-radiation-resistant cooling window with a graded metamaterial structure coating, the high-radiation-resistant cooling window comprising: a first glass, a second glass, louvers, and two window frames;

[0007] The first combination of the high-radiation cooling window consists of a first glass pane, a second glass pane, louvers, and two window frames. The first glass pane and the second glass pane are spaced apart, and the louvers are located between the first glass pane and the second glass pane. The first glass pane, the second glass pane, and the louvers are all fixed between the two window frames.

[0008] The second combination of the high-radiation cooling window is a first glass, a second glass, a louver, and two window frames. The first glass and the second glass are spaced apart, the louver is located outside the second glass or the first glass, and the first glass, the second glass, and the louver are all fixed between the two window frames.

[0009] The surface of the louvers or window frames is integrated with at least one graded metamaterial structure coating.

[0010] Preferably, the hierarchical metamaterial structure coating comprises a bottom layer, a light-functional layer with a micro-hierarchical micro / nano structure, and a hydrophobic protective layer stacked sequentially.

[0011] The optical functional layer, which has a micro-hierarchical micro-nano structure, includes a first polymer and a first high-refractive-index inorganic spectral particle filler.

[0012] Preferably, one surface of the bottom layer is bonded to the surface of the window frame or louver blades, and the other surface is bonded to the light-functional layer of the micro-hierarchical micro-nano structure.

[0013] The bottom layer comprises an organic second polymer and functional fillers;

[0014] The second polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin;

[0015] The functional filler includes corrosion-resistant filler and second high-refractive-index inorganic spectral particles;

[0016] The corrosion-resistant filler includes at least one of zinc powder, sodium hexaphosphate, ferric oxide, zinc phosphate, and aluminum tripolyphosphate;

[0017] The second high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate.

[0018] Preferably, the first polymer comprises at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin.

[0019] The first high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate;

[0020] The first high-refractive-index inorganic spectral particle filler has a mass fraction of 20-50% in the optical functional layer;

[0021] The particle size of the first high-refractive-index inorganic spectral particle filler is 10 nm to 5000 nm;

[0022] Inside the optical functional layer with micro-hierarchical micro-nano structure, the size of the first high-refractive-index inorganic spectral particle filler is distributed in the thickness direction according to a pattern of decreasing size or increasing size.

[0023] Inside the optical functional layer with micro-hierarchical micro / nano structure, the volume fraction of the first high-refractive-index inorganic spectral particle filler is distributed in a pattern from large to small or from small to large along its thickness direction.

[0024] Preferably, the hydrophobic protective layer of the cover includes a third high-molecular-weight polymer and hydrophobic filler, and a third high-refractive-index inorganic spectral particle filler;

[0025] The third polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin;

[0026] The hydrophobic filler includes at least one of silane coupling agent, organosilicon resin, and nano-silica.

[0027] The third high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate.

[0028] The third high-refractive-index inorganic spectral particle filler has a mass fraction of 5-10% in the hydrophobic protective layer of the cover.

[0029] Preferably, the thickness of the optical functional layer of the micro-hierarchical micro / nano structure is 50 μm to 200 μm;

[0030] The thickness of the bottom layer is 10μm to 100μm;

[0031] The particle size of the second high-refractive-index inorganic spectral particles in the bottom layer is 10 nm to 5000 nm.

[0032] The particle size of the corrosion-resistant filler is 200nm to 5000nm;

[0033] The thickness of the hydrophobic protective layer on the surface is 5μm to 100μm;

[0034] The particle size of the third high-refractive-index inorganic spectral particle filler in the hydrophobic protective layer of the cover is 10 nm to 5000 nm.

[0035] Preferably, the bottom layer, the optical functional layer with micro-hierarchical micro-nano structure, and the hydrophobic protective layer further include a diluent, wherein the diluent is xylene;

[0036] The bottom layer comprises a second polymer and a xylene diluent. The second polymer comprises a fluoropolymer and an acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin and xylene is (15-20):(5-10):(25-35).

[0037] Alternatively, the bottom layer comprises a second polymer, an anti-corrosion filler, and xylene. The second polymer comprises fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin, xylene, and anti-corrosion filler is (15-20):(5-10):(25-40):(60-75). The anti-corrosion filler is zinc powder, and the particle size of the anti-corrosion filler is 200nm-5000nm.

[0038] Alternatively, the bottom layer comprises a second polymer, an anti-corrosion filler, xylene, and a second high-refractive-index inorganic spectral particle. The second polymer comprises fluoropolymer and acrylic resin. The mass ratio of the fluoropolymer, acrylic resin, xylene, anti-corrosion filler, and the second high-refractive-index inorganic spectral particle is (15-20):(5-10):(25-40):(60-75):(5-10). The second high-refractive-index inorganic spectral particle is titanium dioxide, and the particle size of the second high-refractive-index inorganic spectral particle is 100 nm to 500 nm.

[0039] Preferably, the optical functional layer with micro-hierarchical micro / nano structure includes multiple superimposed sub-optical functional layers. Each sub-optical functional layer includes a first polymer, a first high-refractive-index inorganic spectral particles, and xylene. The first polymer includes fluoropolymer and acrylic resin. The particle size and mass ratio of the first high-refractive-index inorganic spectral particles are different in different sub-optical functional layers.

[0040] The first high-refractive-index inorganic spectral particles include at least one of titanium dioxide with a particle size of 100 nm to 500 nm, titanium dioxide with a particle size of 500 nm to 800 nm, and titanium dioxide with a particle size of 800 nm to 1400 nm.

[0041] The mass ratio of the fluororesin, acrylic resin, xylene, and the first high-refractive-index inorganic spectral particles is (55-65):(15-25):(60-70):(10-80).

[0042] Preferably, the hydrophobic protective layer comprises a third polymer and xylene, wherein the third polymer comprises fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin, xylene and hydrophobic particles is (55-65):(15-25):(70-80):(10-25).

[0043] Alternatively, the hydrophobic protective layer may comprise a third high-molecular-weight polymer, xylene, and a third high-refractive-index inorganic spectral particle filler. The third high-molecular-weight polymer comprises fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin, xylene, and the third high-refractive-index inorganic spectral particles is (55–65):(15–25):(70–80):(10–25):(15–20). The third high-refractive-index inorganic spectral particles are alumina with a diameter of 100 nm to 300 nm.

[0044] Preferably, the optical functional layer with micro-hierarchical micro / nano structure comprises two sub-optical functional layers from bottom to top: a bottom optical functional layer and an upper optical functional layer.

[0045] The first high-refractive-index inorganic spectral particles in the upper optical functional layer are titanium dioxide with a particle size of 100nm to 500nm.

[0046] The first high-refractive-index inorganic spectral particles in the bottom optical functional layer are titanium dioxide with a particle size of 500nm to 800nm.

[0047] Alternatively, the optical functional layer with micro-hierarchical micro / nano structure may include three sub-optical functional layers from bottom to top: an upper optical functional layer, a middle optical functional layer, and a bottom optical functional layer.

[0048] The first high-refractive-index inorganic spectral particles in the upper optical functional layer are titanium dioxide with a particle size of 100nm to 500nm.

[0049] The first high-refractive-index inorganic spectral particles in the middle optical functional layer are titanium dioxide with a particle size of 500 nm to 800 nm.

[0050] The first high-refractive-index inorganic spectral particles in the bottom optical functional layer are titanium dioxide with a particle size of 800 nm to 1400 nm.

[0051] Alternatively, the first high-refractive-index inorganic spectral particles in the optical functional layer may comprise a mixture of titanium dioxide with a mass ratio of (3-7):(1-3):(1-3) and particle sizes of 100nm-500nm, 500nm-800nm, and 800nm-1400nm, respectively.

[0052] Secondly, the present invention also provides a method for preparing a high-radiation cooling window with a graded metamaterial structure coating, wherein the first glass, the second glass, and the louvers are all installed between the outer frame of the window to obtain a cooling window with a graded metamaterial structure high-radiation cooling coating.

[0053] The louvers or window frames are all integrated with at least one graded metamaterial structure coating.

[0054] The method for preparing the hierarchical metamaterial structure coating includes the following steps:

[0055] Optional high-refractive-index inorganic spectral particles, optional anti-corrosion fillers, and optional diluents are added to the second polymer and stirred to obtain the bottom mixture.

[0056] Apply the base coat mixture to the surface of the window frame or louver slats to form the base coat;

[0057] First high-refractive-index inorganic spectral particle fillers with different physical properties and optional diluents are added to the first polymer and stirred to obtain multiple spectral functional mixtures.

[0058] Multiple spectral functional mixtures are sequentially coated onto the surface of the base layer to form a light functional layer with a micro-nano structure.

[0059] Optional high-refractive-index inorganic spectral particles, hydrophobic materials, and optional diluents are added to the third high-molecular-weight polymer and stirred to obtain a hydrophobic protective layer mixture.

[0060] A mixture of hydrophobic protective layer materials is coated onto the surface of an optical functional layer with a micro-hierarchical micro-nano structure to form a hydrophobic protective layer.

[0061] Thirdly, the present invention also provides an application of the high-radiation cooling window with a graded metamaterial structure coating as described above, or the high-radiation cooling window with a graded metamaterial structure coating prepared by the preparation method described above, in office buildings, factories, residential buildings, guard booths, mobile homes, glass curtain walls, exhibition halls and commercial centers, as well as automobiles, trains, airplanes, ships and yachts, as well as space capsules, drones, armored vehicles, fighter jets and helicopters.

[0062] The cooling window with a hierarchical metamaterial structure and a high-radiation resistant coating, and its preparation method, of the present invention have the following technical advantages compared with the prior art:

[0063] 1. The high-radiation cooling window with a hierarchical metamaterial structure coating of the present invention integrates the hierarchical metamaterial structure coating onto the outer frame and the surface of the louver blades of the window, thus forming a high-radiation cooling window with a hierarchical metamaterial structure coating. This significantly reduces the absorption of external solar radiation heat by the window and emits its own heat into the environment as strong mid-infrared radiation. The hierarchical metamaterial structure coating includes a base layer, a photofunctional layer, and a hydrophobic protective layer. By hierarchically designing the size and volume fraction of the micro-nano structure, the coating exhibits a regular arrangement in the thickness direction, optimizing the reflection path of different wavelengths of radiation within the coating and achieving excellent spectral modulation performance. The high-radiation cooling window with the hierarchical metamaterial structure coating has extremely strong reflectivity greater than 0.96 in the ultraviolet-visible-near-infrared band (0.25μm-2.5μm) and extremely strong emission characteristics greater than 0.95 in the mid-infrared band (8μm-13μm). Furthermore, the graded metamaterial structure coating exhibits excellent service performance. Tests show that its adhesion is Grade 1; it shows no wrinkles, cracks, or peeling after a 1kg hammer impact from a height of 50cm; the paint film remains undamaged after 5000 washes; there is no red rust on the surface after 200 hours of acetic acid salt spray testing; no abnormalities were observed after 168 hours of immersion in 5% sulfuric acid solution; no abnormalities were observed after 48 hours of immersion in saturated NaOH solution; and no bubbles or cracks were observed after 1000W solar spectrum irradiation (including 60W 300nm-400nm ultraviolet irradiation) and 2000 hours of artificial climate aging. This meets the requirements for long-term use of high-radiation cooling windows in various scenarios.

[0064] 2. The high-radiation-resistant cooling window of this invention, equipped with a graded metamaterial structure coating, exhibits extremely strong reflective properties in the ultraviolet-visible-near-infrared band (0.25-2.5μm) and extremely strong emission properties in the mid-infrared band (8-13μm). Actual testing shows that, compared to ordinary windows, the indoor temperature of a room using the graded metamaterial structure high-radiation-resistant cooling window is reduced by 8.05℃.

[0065] 3. The high-radiation-resistant cooling window with a graded metamaterial structure coating of the present invention has excellent high-radiation resistance and efficient passive cooling characteristics. It can be applied to windows of buildings such as office buildings, factories, residential buildings, guard booths, mobile homes, glass curtain walls, exhibition halls and commercial centers, as well as windows of vehicles such as automobiles, trains, airplanes, ships and yachts, and windows of special equipment such as space capsules, drones, armored vehicles, fighter jets and helicopters. Based on the spectral regulation performance of the cooling window that adapts to indoor temperature, it significantly improves the indoor thermal comfort of buildings, vehicles, special equipment guard booths and other places under high solar radiation environments. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0067] Figure 1 This is a schematic diagram of the structure of the graded metamaterial structural coating of the present invention applied to the surface of a louver blade;

[0068] Figure 2 This is a schematic diagram of the high-radiation cooling window with a graded metamaterial structure coating according to one embodiment of the present invention.

[0069] Figure 3 This is a schematic diagram of the high-radiation cooling window with a graded metamaterial structure coating according to another embodiment of the present invention;

[0070] Figure 4 This is a schematic diagram illustrating the principle of the high-radiation-resistant cooling window with a graded metamaterial structure coating of the present invention, which regulates the indoor ambient temperature under different temperature environments.

[0071] Figure 5 A comparison of the indoor temperatures of a guard booth using the cooling louvers of this invention and a guard booth using ordinary louvers;

[0072] Figure 6 This is a cross-sectional SEM image of the graded metamaterial structure coating in Embodiment 17 of the present invention, and the Ti element distribution along the interface direction. Detailed Implementation

[0073] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0074] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0075] In the embodiments section, we focus on discussing cooling windows using transparent glass, with louvers as the main window type, and the louver blades being made of aluminum. The manufacturing methods for cooling windows of other colors, transparency, and coatings are similar to those in the embodiments below, and all fall within the scope of protection of this invention.

[0076] This application provides a high-radiation-resistant cooling window with a graded metamaterial structure coating, such as... Figures 2-3 As shown, the high-radiation cooling window includes: a first glass, a second glass, louvers, and two window frames. The first glass and the second glass are spaced apart, and the louvers are located between the first glass and the second glass. The first glass, the second glass, and the louvers are all fixed between the two window frames.

[0077] Alternatively, the high-radiation cooling window includes: a first glass, a second glass, louvers, and two window frames. The first glass and the second glass are spaced apart, and the louvers are located outside the second glass or the first glass. The first glass, the second glass, and the louvers are all fixed between the two window frames.

[0078] The louver blades and the outer frame of the window are coated with a high-radiation-resistant metamaterial coating with a graded metamaterial structure.

[0079] High-radiation resistant metamaterial coatings include: a light-functional layer with a micro-hierarchical micro / nano structure;

[0080] The optical functional layer with a micro-hierarchical micro-nano structure comprises a first polymer and a first high-refractive-index inorganic spectral particle filler.

[0081] Inside the optical functional layer with a micro-hierarchical micro / nano structure, the size of the first high-refractive-index inorganic spectral particle filler is distributed in a pattern of decreasing size or increasing size in its thickness direction, and / or the volume fraction of the first high-refractive-index inorganic spectral particle filler is distributed in a pattern of decreasing size or increasing size in its thickness direction.

[0082] For details, please refer to Figure 2 As shown, the high-radiation-resistant cooling window structure includes: a first glass pane, a second glass pane, and louvers; all three panes are fixed to the window frame, and are arranged in parallel at intervals. The louver blades and the surface of the window frame are coated with a graded metamaterial structure for high-radiation resistance. The louvers are located between the first and second glass panes. The first and second glass panes can be transparent glass or light green tempered glass.

[0083] Further reference Figure 3 As shown, the high-radiation-resistant cooling window structure includes: a first glass pane, a second glass pane, and louvers; all three panes are fixed to the window frame, and are arranged in parallel at intervals. The louver blades and the surface of the window frame are coated with a graded metamaterial structure for high-radiation resistance. The louvers are located outside the first or second glass pane. The first and second glass panes can be transparent glass or light green tempered glass.

[0084] The present invention relates to a high-radiation-resistant and cooling window with a graded metamaterial structure coating. The window frame and louver blades are made of steel, aluminum alloy, or plastic, and their outer surfaces are coated with a graded metamaterial structure coating. The amount of heat radiation entering the room can be controlled by adjusting the opening angle of the louver blades. The graded metamaterial structure coating uses a polymer as a matrix. According to different functional requirements, micro-nano structures are added to the polymer and coated on the surface of the window frame and louver blades. The louvers are installed in the interlayer of the double-glazed windows or close to the surface of the external environment.

[0085] The hierarchical metamaterial structure coating consists of a base layer, a light-functional layer with micro-hierarchical micro / nano structures, and a hydrophobic protective layer. Based on different functional requirements, the materials and micro / nano structures of each layer are designed specifically. In the light-functional part, the size and volume fraction of the micro / nano structures are further used as a basis to arrange them hierarchically in the thickness direction of the light-functional layer, optimizing the internal optical path. This enables it to have strong reflective properties in the solar spectrum band of 0.3-2.5μm to control the input of external environmental heat radiation, and strong emission capability in the mid-infrared band of 8-13μm to regulate its own heat radiation output.

[0086] The high-radiation cooling window of the present invention, which has a graded metamaterial structure coating, has extremely high solar radiation reflection capability and mid-infrared emission capability. By adjusting the degree of opening and closing of the window, the radiant heat entering the room can be controlled to achieve the effect of adjusting the indoor temperature.

[0087] The high-radiation cooling window with a graded metamaterial structure coating of the present invention is applicable to windows in buildings such as office buildings, factories, residential buildings, guard booths, mobile homes, glass curtain walls, exhibition halls and commercial centers, as well as windows in vehicles such as automobiles, trains, airplanes, ships and yachts, and windows in special equipment such as space capsules, drones, armored vehicles, fighter jets and helicopters. The high-radiation cooling window uses materials, sizes and grading methods of the graded micro-nano structure that are adjusted according to the transparency, color and other characteristics of the glass used in the window to achieve better control effect.

[0088] Specifically, the hierarchical metamaterial structure coating includes: a photoelectric functional layer with a micro-hierarchical micro / nano structure, comprising a first polymer and a first high-refractive-index inorganic spectral particle filler; the photoelectric functional layer has a hierarchical micro / nano structure, characterized in that: within the photoelectric functional layer with the micro-hierarchical micro / nano structure, in its thickness direction, the size of the first high-refractive-index inorganic spectral particle filler follows a pattern of decreasing size or increasing size, and / or, in its thickness direction, the volume fraction of the first high-refractive-index inorganic spectral particle filler follows a pattern of decreasing size or increasing size (i.e., from sparse to dense or from dense to sparse). This structure differs from a structure that is randomly distributed after simply mixing the matrix and filler; the micro / nano structure has a clear regular spatial distribution. The hierarchically adjusted micro / nano structure enables window cooling components to obtain superior spectral performance to achieve the core functions of resisting high radiation and regulating indoor ambient temperature.

[0089] In some embodiments, the first polymeric material includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin, and silicone resin.

[0090] The first high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate.

[0091] The first high-refractive-index inorganic spectral particle filler has a mass fraction of 20-50% in the optical functional layer;

[0092] The particle size of the first high-refractive-index inorganic spectral particle filler is 10 nm to 5000 nm.

[0093] In some embodiments, the thickness of the optical functional layer with micro-hierarchical micro / nano structures is 50 μm to 200 μm.

[0094] In some embodiments, the metamaterial coating further includes an underlayer, one surface of which is bonded to the surface of the window frame or louver blades, and the other surface of which is bonded to the optical functional layer with a micro-nano structure to improve the adhesion strength of the metamaterial coating; it also provides corrosion resistance and additional spectral performance for the overall coating; the underlayer is located between the window frame or louver blades and the spectral modulation layer, possessing strong adhesion properties, and its main function is to enhance the bonding strength between the spectral modulation layer and the surface of the window frame or louver blades, and to provide additional spectral functionality. In some cases, the underlayer is not an essential structure of the metamaterial coating.

[0095] In some embodiments, the substrate comprises an organic second polymer and functional fillers; the substrate provides adhesion and corrosion protection properties for the metamaterial coating as a whole;

[0096] The second polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin;

[0097] Functional fillers include inorganic spectral particles with the second highest refractive index and corrosion-resistant fillers;

[0098] The second high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate.

[0099] Corrosion-resistant fillers include at least one of zinc powder, sodium hexaphosphate, ferric oxide, zinc phosphate, and aluminum tripolyphosphate;

[0100] The functional filler accounts for 70-80% of the mass fraction in the bottom layer, of which the anti-corrosion filler accounts for 60-75% of the mass fraction in the bottom layer, and the remainder is the second high refractive index inorganic spectral particle filler; the particle size of the anti-corrosion filler is 200nm-5000nm, and the particle size of the second high refractive index inorganic spectral particles in the bottom layer is 10nm-5000nm.

[0101] The base material of this metamaterial coating is applied to the surface of the window frame or louver blades by spraying / scraping. The coating thickness is 10μm to 100μm. The final coating appears as a smooth surface on a macroscopic scale, and on a microscopic scale, it contains randomly distributed anti-corrosion materials and spectral materials.

[0102] In some embodiments, the metamaterial coating further includes a hydrophobic protective layer, which is situated above the photofunctional layer having a micro-hierarchical micro / nano structure. This hydrophobic protective layer is transparent or translucent, possesses strong adhesion properties, and provides hydrophobic protection for the coating. Furthermore, this hydrophobic protective layer may be modulated to possess additional spectral characteristics. In some cases of the present invention, the hydrophobic protective layer is not an essential structure of the metamaterial coating.

[0103] The hydrophobic protective layer of the cover includes a third high-molecular-weight polymer and a third high-refractive-index inorganic spectral particle filler;

[0104] The third polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin; the coating has good hydrophobic properties by adding at least one of hydrophobic materials including silane coupling agent, silicone resin and nano silica.

[0105] The third high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate; its diameter is between 10 nm and 5000 nm, and its mass fraction in the hydrophobic protective layer is between 5% and 10%. The hydrophobic protective layer material of this metamaterial coating is applied to the surface of the spectral modulation layer by spraying / scraping, with a coating thickness of 5 μm to 100 μm.

[0106] In some embodiments, the preparation of the underlayer in the metamaterial coating uses a diluent, namely xylene;

[0107] The bottom layer includes a second polymer and xylene. The second polymer includes fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin and xylene is (15-20):(5-10):(25-35).

[0108] Alternatively, the bottom layer comprises a second polymer, an anti-corrosion filler, and xylene. The second polymer comprises fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin, xylene, and anti-corrosion filler is (15-20):(5-10):(25-40):(60-75). The anti-corrosion filler is zinc powder, and the particle size of the anti-corrosion filler is 200nm-5000nm.

[0109] Alternatively, the bottom layer includes a second polymer, an anti-corrosion filler, xylene, and a second high-refractive-index inorganic spectral particle. The second polymer includes fluoropolymer and acrylic resin. The mass ratio of the fluoropolymer, acrylic resin, xylene, anti-corrosion filler, and the second high-refractive-index inorganic spectral particle is (15-20):(5-10):(25-40):(60-75):(5-10). The second high-refractive-index inorganic spectral particle is titanium dioxide, and the particle size of the second high-refractive-index inorganic spectral particle is 100nm-500nm.

[0110] In some embodiments, the preparation of the hydrophobic protective layer on the top of the metamaterial coating uses a diluent, xylene;

[0111] The hydrophobic protective layer comprises a third polymer, a hydrophobic filler, and xylene. The third polymer comprises fluoropolymer and acrylic resin. The hydrophobic filler is a silane coupling agent. The mass ratio of the fluoropolymer, acrylic resin, silane coupling agent, and xylene is (55-65):(15-25):(70-80):(15-25).

[0112] Alternatively, the hydrophobic protective layer may include a third high-molecular-weight polymer, xylene, and a third high-refractive-index inorganic spectral particle filler. The third high-molecular-weight polymer may include fluoropolymer and acrylic resin. The mass ratio of the fluoropolymer, acrylic resin, xylene, silane coupling agent, and the third high-refractive-index inorganic spectral particles may be (55–65): (15–25): (70–80): (15–25): (5–15). The third high-refractive-index inorganic spectral particles may be alumina with a diameter of 100 nm to 300 nm.

[0113] In some embodiments, the optical functional layer includes a plurality of superimposed sub-optical functional layers, each optical functional layer including a first polymer, a first high refractive index inorganic spectral particles, and xylene, wherein the first polymer includes fluoropolymer and acrylic resin.

[0114] The first high-refractive-index inorganic spectral particles include at least one of titanium dioxide with a particle size of 100 nm to 500 nm, titanium dioxide with a particle size of 500 nm to 800 nm, and titanium dioxide with a particle size of 800 nm to 1400 nm.

[0115] The mass ratio of fluoropolymer, acrylic resin, xylene, and first high refractive index inorganic spectral particles is (55-65):(15-25):(60-70):(20-80).

[0116] In some embodiments, the optical functional layer with a micro-hierarchical micro-nano structure consists of two sub-optical functional layers, a bottom optical functional layer and an upper optical functional layer, from bottom to top.

[0117] The first high-refractive-index inorganic spectral particles in the upper optical functional layer are titanium dioxide with a particle size of 100nm to 500nm;

[0118] The first high-refractive-index inorganic spectral particles in the bottom optical functional layer are titanium dioxide with a particle size of 500 nm to 800 nm;

[0119] In some embodiments, the optical functional layer with micro-hierarchical micro-nano structure includes three sub-optical functional layers from bottom to top: an upper optical functional layer, a middle optical functional layer, and a bottom optical functional layer.

[0120] The first high-refractive-index inorganic spectral particles in the upper optical functional layer are titanium dioxide with a particle size of 100nm to 500nm;

[0121] The first high-refractive-index inorganic spectral particles in the middle optical functional layer are titanium dioxide with a particle size of 500 nm to 800 nm;

[0122] The first high-refractive-index inorganic spectral particles in the bottom optical functional layer are titanium dioxide with a particle size of 800 nm to 1400 nm.

[0123] In some embodiments, the first high-refractive-index inorganic spectral particles in the optical functional layer having a micro-hierarchical micro-nano structure include a mixture of titanium dioxide with a mass ratio of (3-7):(1-3):(1-3) and particle sizes of 100nm-500nm, 500nm-800nm, and 800nm-1400nm, respectively.

[0124] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned high-radiation cooling window with a hierarchical metamaterial structure coating, comprising:

[0125] A high-radiation-resistant metamaterial coating is prepared on the surface of a window frame or louver blades. The high-radiation-resistant metamaterial coating includes a hierarchical micro / nano structured optical functional layer. The preparation method of the optical functional layer with the micro-hierarchical micro / nano structure includes:

[0126] A first high-refractive-index inorganic spectral particle filler and an optional diluent are added to a first polymer and stirred to obtain a spectral functional mixture.

[0127] The spectral functional mixture is coated on the surface of window frame or louver blades to form a light functional layer with micro-hierarchical micro-nano structure, thus obtaining a hierarchical metamaterial structure coating.

[0128] Alternatively, the high-irradiation-resistant metamaterial coating includes a base layer and a photofunctional layer with a micro-hierarchical micro / nano structure. The preparation method of the high-irradiation-resistant metamaterial coating includes the following steps:

[0129] Optional high-refractive-index inorganic spectral particles, optional anti-corrosion fillers, and optional diluents are added to the second polymer and stirred to obtain the bottom mixture.

[0130] Apply the base coat mixture to the surface of the window frame or louver slats to form the base coat;

[0131] A first high-refractive-index inorganic spectral particle filler and an optional diluent are added to a first polymer and stirred to obtain a spectral functional mixture.

[0132] A spectral functional blend is coated onto the surface of the substrate to form a light functional layer with a micro-nano structure.

[0133] Alternatively, the high-radiation-resistant metamaterial coating comprises a base layer, a photofunctional layer with a micro-hierarchical micro / nano structure, and a hydrophobic protective layer, and the preparation method of the high-radiation-resistant metamaterial coating includes the following steps:

[0134] Optional high-refractive-index inorganic spectral particles, optional anti-corrosion fillers, and optional diluents are added to the second polymer and stirred to obtain the bottom mixture.

[0135] Apply the base coat mixture to the surface of the window frame or louver slats to form the base coat;

[0136] First high-refractive-index inorganic spectral particle fillers with different physical properties and optional diluents are added to the first polymer and stirred to obtain multiple spectral functional mixtures.

[0137] Multiple spectral functional mixtures are sequentially coated onto the surface of the base layer to form a light functional layer with a micro-nano structure.

[0138] Optional high-refractive-index inorganic spectral particles, hydrophobic materials, and optional diluents are added to the third high-molecular-weight polymer and stirred to obtain a hydrophobic protective layer mixture.

[0139] A mixture of hydrophobic protective layer materials is coated onto the surface of an optical functional layer with a micro-nano structure to form a hydrophobic protective layer.

[0140] By installing the first glass, the second glass, and the louvers with the high-radiation-resistant metamaterial coating between the window frame with the high-radiation-resistant metamaterial coating, a high-radiation-resistant cooling window with a graded metamaterial structure and a high-radiation-resistant coating is obtained.

[0141] For details, please refer to Figure 1 As shown, a hierarchical metamaterial structure coating was prepared on the surface of a louver blade. Specifically, a base layer, a light-functional layer, and a hydrophobic protective layer were sequentially prepared on the surface of the louver blade. Furthermore, from... Figure 1 The magnified view of the mid-light functional layer shows that, inside the light functional layer, in its thickness direction, the size of the first high-refractive-index inorganic spectral particle filler is distributed in a pattern of decreasing size or increasing size; in its thickness direction, the volume fraction of the first high-refractive-index inorganic spectral particle filler is distributed in a pattern of decreasing size or increasing size (i.e., from sparse to dense or from dense to sparse).

[0142] Further reference Figure 4 The diagram illustrates the surface temperature of the louver blades and the indoor temperature under different irradiation environments after the hierarchical metamaterial structure coating of the present invention was prepared on the louver. Under strong solar irradiation, closing the louver or reducing the opening angle of the louver allows the louver with the metamaterial coating of the present invention to reflect sunlight, thereby regulating the indoor temperature; under weak solar irradiation, opening the louver allows for the regulation of the indoor temperature.

[0143] The metamaterial coating of this invention can improve the radiation resistance of window building materials, including improving the reflectivity of the carrier surface to solar radiation bands and improving the radiation characteristics of the carrier in the mid-infrared band. The metamaterial coating of this invention can be bonded to the carrier through methods including, but not limited to, spraying, brushing, roller coating, electrostatic spraying, bonding, lamination, hot pressing, and other surface bonding methods or chemical fusion methods. The macroscopic morphology of the metamaterial coating of this invention includes various periodic or pseudo-periodic forms such as layered planar, curved, textured, and sand-wall-like structures.

[0144] The metamaterial coating provided by this invention uses organic polymers and inorganic spectral particles as the main components. By constructing a structure that integrates macroscopic structure and hierarchically modulates microscopic structure, it achieves the function of regulating the reflectivity and emissivity of the solar spectrum (0.3-2.5μm) and the mid-infrared spectrum (8-13μm).

[0145] Based on the same inventive concept, this invention also provides a method for preparing a high-radiation-resistant cooling window with a graded metamaterial structure coating. The high-radiation-resistant cooling window with a graded metamaterial structure coating prepared by this invention can be used in architectural windows such as office buildings, factories, residential buildings, guard booths, mobile homes, glass curtain walls, exhibition halls and commercial centers, as well as windows of transportation vehicles such as automobiles, trains, airplanes, ships and yachts, and windows of special equipment such as space capsules, drones, armored vehicles, fighter jets and helicopters.

[0146] The high-radiation-resistant cooling window of this invention, with its graded metamaterial structure coating, possesses excellent high-radiation resistance and efficient passive cooling characteristics. It is applicable to windows in buildings such as office buildings, factories, residential buildings, guard booths, mobile homes, glass curtain walls, exhibition halls, and commercial centers, as well as windows in vehicles such as automobiles, trains, airplanes, ships, and yachts, and windows in special equipment such as space capsules, drones, armored vehicles, fighter jets, and helicopters. Based on the spectral regulation performance of the cooling window, which is adapted to indoor temperature, it significantly improves the indoor thermal comfort of buildings, vehicles, and special equipment in high solar radiation environments.

[0147] The metamaterial coating and its preparation method of this application are further illustrated below with specific embodiments. This section further illustrates the content of the present invention in conjunction with specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0148] The metamaterial coating structure of this embodiment includes a base layer, a photofunctional layer, and a hydrophobic protective layer. The photofunctional layer is mandatory, while the base layer and the hydrophobic protective layer are optional and can be added or removed depending on the specific carrier material. The following will describe the structure of each layer of the metamaterial coating through a scheme, and finally, through an embodiment, further illustrate the specific metamaterial coating. Unless otherwise specified, all formulations are weight ratios, all layers are bonded by spraying, and the curing method is one or more of natural air drying and high-temperature baking.

[0149] In some embodiments of this invention, louvers are used as the main form of windows. Other windows with opening and closing mechanisms and covering capabilities are all within the scope of patent protection.

[0150] Unless otherwise specified, in the embodiments of the present invention, the coating underlayer is applied to the surface of the louver blades, the light-functional layer is applied to the surface of the underlayer, and the topcoat hydrophobic protective layer is applied to the surface of the light-functional layer.

[0151] Unless otherwise specified, all embodiments of this invention use double-glazed windows, which are currently widely used, as the experimental scenario.

[0152] The reflectivity listed in this embodiment refers to the proportion of the radiant energy incident on the surface of the louver blades that is reflected from the surface of the louver blades.

[0153] The polymer carrier used in the embodiments of this invention is PVDF fluororesin, which requires high-temperature baking during film formation. Other types of fluororesins, acrylic resins, epoxy resins and other polymer materials do not require high-temperature baking during film formation, but their preparation processes are similar to those of this patent and should also be within the scope of protection of this patent.

[0154] In the following examples, PVDF fluoropolymer and acrylic resin are used, wherein the PVDF fluoropolymer is a PVDF emulsion from Dongguan Suyu Plastics Technology Co., Ltd.; and the acrylic resin is an acrylic emulsion provided by Henan Dazao Chemical Co., Ltd.

[0155] Example 1

[0156] This embodiment provides underlying preparation methods, including Scheme 1, Scheme 2, and Scheme 3.

[0157] Option 1

[0158] This solution provides a basic preparation method, including the following steps:

[0159] S1. Mix 50g of PVDF fluororesin with 25g of acrylic resin and stir for 15min to obtain the matrix material;

[0160] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain the bottom mixture.

[0161] S3. Spray the bottom layer mixture from S2 onto the surface of the louver blades to form a coating structure with a flat appearance and a dense internal microstructure. Let it stand for 10 minutes, bake at 230℃ for 20 minutes, and after curing, the bottom layer is obtained with a thickness of 10μm.

[0162] Option 2

[0163] This solution provides a basic preparation method, including the following steps:

[0164] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0165] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0166] S3. Add 130g of zinc powder with a particle size of 5μm to the matrix material diluted in S2 as an anti-corrosion material, stir for 20min, and obtain the bottom mixture.

[0167] S4. Spray the bottom layer mixture from S3 onto the surface of the louver blades to form a coating structure with a flat appearance and a dense internal microstructure. Let it stand for 10 minutes, bake at 230℃ for 20 minutes, and after curing, the bottom layer is obtained with a thickness of 10μm.

[0168] Option 3

[0169] This solution provides a basic preparation method, including the following steps:

[0170] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0171] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0172] S3. Add 130g of zinc powder with a particle size of 5μm to the matrix material diluted in S2 as an anti-corrosion material, stir for 20min, and obtain intermediate bottom layer material;

[0173] S4. Add 15g of titanium dioxide with a particle size of 400nm to the intermediate bottom material in S3, stir for 20min, and obtain the bottom mixture.

[0174] S5. Spray the bottom layer mixture from S4 onto the surface of the louver blades to form a coating structure with a flat appearance and a dense internal microstructure. Let it stand for 10 minutes, bake at 230℃ for 20 minutes, and after curing, the bottom layer is obtained with a thickness of 10μm.

[0175] Example 2

[0176] This embodiment provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including scheme 1, scheme 2, scheme 3, scheme 4, scheme 5, and scheme 6.

[0177] Option 1

[0178] This solution provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including the following steps:

[0179] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0180] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0181] S3. Add 50g of titanium dioxide with a particle size of 400nm to the matrix material diluted in S2, stir for 25min to obtain the optical functional layer mixture.

[0182] S4. Spray the optical functional layer mixture from S3 onto the bottom surface, let it stand for 15 minutes, bake at 230℃ for 20 minutes, and after curing, obtain the optical functional layer with a thickness of 150μm.

[0183] Option 2

[0184] This solution provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including the following steps:

[0185] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0186] S2. Mix the matrix material from S1 with 25g of xylene and stir for 10min to obtain a diluted matrix material;

[0187] S3. Prepare two portions of diluted matrix material according to the method in S2;

[0188] S4. Add 50g of titanium dioxide with a particle size of 400nm to the first diluted matrix material, stir for 25min to obtain the upper optical functional layer mixture.

[0189] S5. Add 50g of titanium dioxide with a particle size of 800nm ​​to the matrix material diluted in the bottom layer, stir for 25min to obtain the bottom optical functional layer mixture.

[0190] S6. Spray the bottom optical functional layer mixture from S4 onto the bottom surface, let it stand for 15 minutes, bake at 230℃ for 20 minutes, and cure to obtain the first optical functional layer; spray the upper optical functional layer mixture from S5 onto the surface of the bottom optical functional layer, let it stand for 15 minutes, bake at 230℃ for 20 minutes, and cure to obtain the bottom optical functional layer; the thickness of both the upper and bottom optical functional layers is 75μm; the upper and bottom optical functional layers are stacked to form the entire optical functional layer with a micro-hierarchical micro-nano structure.

[0191] The optical functional layer prepared by this method has a hierarchical micro-nano structure, which is characterized by two levels of particle diameter that increase in size along the thickness of the film.

[0192] Option 3

[0193] This solution provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including the following steps:

[0194] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0195] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0196] S3. Prepare three portions of diluted matrix material according to the method in S2;

[0197] S4. Add 50g of titanium dioxide with a particle size of 400nm to the first diluted matrix material, stir for 25min to obtain the upper optical functional layer mixture.

[0198] S5. Add 50g of titanium dioxide with a particle size of 800nm ​​to the second diluted matrix material, stir for 25min to obtain the middle layer optical functional layer mixture.

[0199] S6. Add 50g of titanium dioxide with a particle size of 1000nm to the third diluted matrix material, stir for 25min to obtain the bottom optical functional layer mixture.

[0200] S7. Spray the bottom layer optical functional layer mixture from S4 onto the bottom layer surface, let stand for 15 minutes, and bake at 230℃ for 20 minutes to cure; Spray the middle layer optical functional layer mixture from S5 onto the bottom layer optical functional layer surface, let stand for 15 minutes, and bake at 230℃ for 20 minutes to cure; Spray the top layer optical functional layer mixture from S6 onto the middle layer optical functional layer surface, let stand for 15 minutes, and bake at 230℃ for 20 minutes to cure; The thickness of the top layer, middle layer, and bottom layer optical functional layers is 50μm; The top layer, middle layer, and bottom layer optical functional layers are stacked to form the entire optical functional layer with a micro-hierarchical micro-nano structure.

[0201] The optical functional layer prepared by this method has a hierarchical structure, which is characterized by three levels of particle diameter along the thickness direction of the film, ranging from small to large.

[0202] Option 4

[0203] This solution provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including the following steps:

[0204] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0205] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0206] S3. Prepare two portions of diluted matrix material according to the method in S2;

[0207] S4. Add 50g of titanium dioxide with a particle size of 400nm to the first diluted matrix material, stir for 25min to obtain the bottom optical functional layer mixture.

[0208] S5. Add 25g of titanium dioxide with a particle size of 800nm ​​to the second diluted matrix material, stir for 25min to obtain the upper optical functional layer mixture.

[0209] S6. Spray the bottom optical functional layer mixture from S4 onto the bottom surface, let it stand for 15 minutes, and bake it at 230℃ for 20 minutes to cure. Spray the top optical functional layer mixture from S5 onto the bottom optical functional layer surface, let it stand for 15 minutes, and bake it at 230℃ for 20 minutes to cure. The second optical functional layer is obtained after curing. The thickness of the first and second optical functional layers is 75μm. The top and bottom optical functional layers are stacked to form the entire optical functional layer with a micro-hierarchical micro-nano structure.

[0210] The optical functional layer prepared by this method has a hierarchical structure, which is characterized by two levels of particle diameter along the thickness direction of the film layer, and two levels of particle volume fraction, from large to small.

[0211] Option 5

[0212] This solution provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including the following steps:

[0213] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0214] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0215] S3. Prepare three portions of diluted matrix material according to the method in S2;

[0216] S4. Add 50g of titanium dioxide with a particle size of 400nm to the first diluted matrix material, stir for 25min to obtain the upper optical functional layer mixture.

[0217] S5. Add 25g of titanium dioxide with a particle size of 800nm ​​to the second diluted matrix material, stir for 25min to obtain the middle layer optical functional layer mixture.

[0218] S6. Add 15g of titanium dioxide with a particle size of 1000nm to the third diluted matrix material, stir for 25min to obtain the bottom optical functional layer mixture.

[0219] S7. Spray the bottom layer optical functional layer mixture from S4 onto the bottom layer surface, let stand for 15 minutes, bake at 230℃ for 20 minutes, and cure. Spray the middle layer optical functional layer mixture from S5 onto the bottom layer optical functional layer surface, let stand for 15 minutes, bake at 230℃ for 20 minutes, and cure. Spray the top layer optical functional layer mixture from S6 onto the middle layer optical functional layer surface, let stand for 15 minutes, bake at 230℃ for 20 minutes, and cure. The thickness of the top functional layer, middle optical functional layer, and bottom optical functional layer is 50μm, which are stacked to form the entire optical functional layer with a micro-hierarchical micro-nano structure.

[0220] The optical functional layer prepared by this method has a hierarchical structure, which is characterized by three levels of particle diameter along the thickness direction of the film layer, and three levels of particle volume fraction from large to small.

[0221] Option 6

[0222] This solution provides a method for fabricating an optical functional layer with a micro-hierarchical micro / nano structure, including the following steps:

[0223] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0224] S2. Mix the matrix material from S1 with 150g of xylene and stir for 10min to obtain a diluted matrix material;

[0225] S3. Titanium dioxide particles with a particle size of 400 nm, 800 nm, and 1000 nm are mixed in a mass ratio of 5:2:1 to obtain titanium dioxide mixed particles.

[0226] S4. Add 50g of titanium dioxide mixed particles from step S3 to the matrix material diluted in S2, stir for 25min, and obtain the optical functional layer mixture.

[0227] S5. Spray the optical functional layer mixture from S4 onto the bottom layer surface, let it stand for 20 minutes, bake at 230℃ for 20 minutes, and after curing, obtain an optical functional layer with a micro-hierarchical micro-nano structure with a thickness of 150μm. During the coating curing process, as the internal particles gradually deposit under the action of gravity, the final distribution state from small particle size to large particle size is formed in the coating thickness direction from the surface layer to the bottom layer.

[0228] The optical functional layer prepared by this method has a hierarchical structure, which is characterized by a gradual distribution of particle diameter from small to large along the thickness direction of the film.

[0229] Example 3

[0230] This embodiment provides a method for preparing a hydrophobic protective layer, including Scheme 1, Scheme 2, and Scheme 3.

[0231] Option 1

[0232] This solution provides a method for preparing a hydrophobic protective layer, including the following steps:

[0233] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0234] S2. Mix the matrix material in S1 with 75g of xylene and stir for 10min to obtain the hydrophobic protective layer mixture.

[0235] S3. Spray the hydrophobic protective layer mixture from S2 onto the surface of the photofunctional layer, bake at 230℃ for 20 minutes, and cure to obtain the hydrophobic protective layer; the thickness of the hydrophobic protective layer is 20μm.

[0236] Option 2

[0237] This solution provides a method for preparing a hydrophobic protective layer, including the following steps:

[0238] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0239] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0240] S3. Add 20g of alumina with a particle size of 500nm to the matrix material diluted in S2, stir for 25min to obtain the hydrophobic protective layer mixture.

[0241] S4. Spray the hydrophobic protective layer mixture from S3 onto the surface of the photofunctional layer, let it stand for 20 minutes, then bake it at 230℃ for 20 minutes. After curing, the hydrophobic protective layer is obtained; the thickness of the hydrophobic protective layer is 20μm.

[0242] Option 3

[0243] This solution provides a method for preparing a hydrophobic protective layer on a topcoat, including the following steps:

[0244] S1. Mix 50g of fluororesin with 25g of acrylic resin and stir for 15 minutes to obtain the matrix material.

[0245] S2. Mix the matrix material from S1 with 75g of xylene and stir for 10min to obtain a diluted matrix material;

[0246] S3. Add 20g of alumina with a particle size of 500nm to the matrix material diluted in S2, stir for 25min to obtain the intermediate mixture of the hydrophobic protective layer.

[0247] S4. Add 15g of hydrophobic nano-silica with a particle size of 20nm to the matrix material diluted in S3, stir for 25min to obtain the hydrophobic protective layer mixture.

[0248] S4. Spray the hydrophobic protective layer mixture from S3 onto the surface of the photofunctional layer, let it stand for 20 minutes, then bake it at 230℃ for 20 minutes to cure and obtain the hydrophobic protective layer; the thickness of the hydrophobic protective layer is 20μm.

[0249] Example 4

[0250] This embodiment provides a graded metamaterial structure coating, which includes only a light-functional layer. The light-functional layer mixture is sprayed onto the surface of the carrier material according to the method of scheme 3 in embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0251] Example 5

[0252] This embodiment provides a graded metamaterial structure coating, which includes only a light-functional layer. The light-functional layer mixture is sprayed onto the surface of the louver blades according to the method of scheme 5 in embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0253] Example 6

[0254] This embodiment provides a graded metamaterial structure coating, which includes only a light-functional layer. The light-functional layer mixture is sprayed onto the surface of the louver blades according to the method of scheme 6 in embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0255] Example 7

[0256] This embodiment provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of Scheme 1 in Embodiment 1 and letting it stand for 20 minutes. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 3 in Embodiment 2 and baked at 230°C for 20 minutes to form the light-functional layer.

[0257] Example 8

[0258] This embodiment provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of Scheme 1 in Embodiment 1 and letting it stand for 20 minutes. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 5 in Embodiment 2 and baked at 230°C for 20 minutes to form the light-functional layer.

[0259] Example 9

[0260] This embodiment provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of a carrier material (specifically an aluminum louver) according to the method of Scheme 1 in Embodiment 1, letting it stand for 20 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 6 in Embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0261] Example 10

[0262] This embodiment provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 20 minutes, baking at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 3 in embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0263] Example 11

[0264] This embodiment provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 20 minutes, baking at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 5 in embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0265] Example 12

[0266] This embodiment provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 20 minutes, baking at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 6 in embodiment 2, and baked at 230°C for 20 minutes to form the light-functional layer.

[0267] Example 13

[0268] This embodiment provides a graded metamaterial structure coating, including a base layer, a photofunctional layer, and a hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of Scheme 3 in Embodiment 1, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the photofunctional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 3 in Embodiment 2, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Finally, the hydrophobic protective layer mixture is sprayed onto the surface of the photofunctional layer according to the method of Scheme 1 in Embodiment 3, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the hydrophobic protective layer.

[0269] Example 14

[0270] This embodiment provides a graded metamaterial structure coating, including a base layer, a photofunctional layer, and a hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 15 minutes, baking at 230°C for 20 minutes, and curing. Then, the photofunctional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 5 in embodiment 2, letting it stand for 15 minutes, baking at 230°C for 20 minutes, and curing. Finally, the hydrophobic protective layer mixture is sprayed onto the surface of the photofunctional layer according to the method of scheme 1 in embodiment 3, letting it stand for 20 minutes, and baking at 230°C for 20 minutes to form the hydrophobic protective layer.

[0271] Example 15

[0272] This embodiment provides a graded metamaterial structure coating, including a base layer, a photofunctional layer, and a top hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 15 minutes, baking at 230°C for 20 minutes, and curing. Then, the photofunctional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 6 in embodiment 2, letting it stand for 15 minutes, baking at 230°C for 20 minutes, and curing. Finally, the top hydrophobic protective layer mixture is sprayed onto the surface of the photofunctional layer according to the method of scheme 1 in embodiment 3, letting it stand for 20 minutes, and baking at 230°C for 20 minutes to form the top hydrophobic protective layer.

[0273] Example 16

[0274] This embodiment provides a graded metamaterial structure coating, including a base layer, a photofunctional layer, and a hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 15 minutes, baking at 230°C for 20 minutes, and curing. Then, the photofunctional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 3 in embodiment 2, letting it stand for 15 minutes, baking at 230°C for 20 minutes, and curing. Finally, the hydrophobic protective layer mixture is sprayed onto the surface of the photofunctional layer according to the method of scheme 3 in embodiment 3, letting it stand for 20 minutes, and baking at 230°C for 20 minutes to form the hydrophobic protective layer.

[0275] Example 17

[0276] This embodiment provides a graded metamaterial structure coating, including a base layer, a photofunctional layer, and a hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the photofunctional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 5 in embodiment 2, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Finally, the hydrophobic protective layer mixture is sprayed onto the surface of the photofunctional layer according to the method of scheme 3 in embodiment 3, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the hydrophobic protective layer.

[0277] Example 18

[0278] This embodiment provides a graded metamaterial structure coating, including a base layer, a photofunctional layer, and a hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the photofunctional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 6 in embodiment 2, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Finally, the hydrophobic protective layer mixture is sprayed onto the surface of the photofunctional layer according to the method of scheme 3 in embodiment 3, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the hydrophobic protective layer.

[0279] Example 19

[0280] This embodiment provides a graded metamaterial structure coating, including a base layer, a light-functional layer, and a hydrophobic protective topcoat. The construction process is exactly the same as in Embodiment 17. The difference is that the louvers prepared in this embodiment are installed in the window interlayer with light green glass.

[0281] Example 20

[0282] This embodiment provides a graded metamaterial structure coating, including a base layer, a light-functional layer, and a hydrophobic protective topcoat. The construction process is exactly the same as in Embodiment 17. The difference is that the louvers prepared in this embodiment are installed on the outermost surface of the window closest to the outside.

[0283] Comparative Example 1

[0284] This comparative example provides aluminum blinds with only the original protective coating and no additional surface treatment.

[0285] Comparative Example 2

[0286] This comparative example provides aluminum blinds with only the original protective coating, using only acrylic resin coating to form an additional protective layer.

[0287] Comparative Example 3

[0288] This comparative example provides a commonly used spectral modulation coating form, which includes only a light functional layer and does not have a hierarchical structure in the spectral functional layer. The light functional layer mixture is sprayed onto the surface of the louver blade according to the method of Scheme 1 in Example 2, left to stand for 20 minutes and baked at 230°C for 20 minutes to form the light functional layer.

[0289] Comparative Example 4

[0290] This comparative example provides a graded metamaterial structure coating, which includes only a light-functional layer. The light-functional layer mixture is sprayed onto the surface of the louver blades according to the method of Scheme 2 in Example 2, left to stand for 20 minutes, and then baked at 230°C for 20 minutes to form the light-functional layer.

[0291] Comparative Example 5

[0292] This comparative example provides a graded metamaterial structure coating, which includes only a light-functional layer. The light-functional layer mixture is sprayed onto the surface of the louver blades according to the method of scheme 4 in Example 2, left to stand for 20 minutes, and then baked at 230°C for 20 minutes to form the light-functional layer.

[0293] Comparative Example 6

[0294] This comparative example provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of a louver blade according to the method of Scheme 1 in Example 1, letting it stand for 20 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 1 in Example 2, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the light-functional layer.

[0295] Comparative Example 7

[0296] This comparative example provides a graded metamaterial structure coating, including a base layer and a light-functional layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of Scheme 3 in Example 1, letting it stand for 20 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 1 in Example 2, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the light-functional layer.

[0297] Comparative Example 8

[0298] This comparative example provides a graded metamaterial structure coating, including a base layer, a light-functional layer, and a hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of Scheme 3 in Example 1, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of Scheme 1 in Example 2, letting it stand for 20 minutes, baking it at 230°C for 20 minutes, and curing it. Finally, the hydrophobic protective layer mixture is sprayed onto the surface of the light-functional layer according to the method of Scheme 3 in Example 3, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the hydrophobic protective layer.

[0299] Comparative Example 9

[0300] This embodiment provides a graded metamaterial structure coating, including a base layer, a light-functional layer, and a top hydrophobic protective layer. The base layer is formed by spraying the base layer mixture onto the surface of the louver blades according to the method of scheme 3 in embodiment 1, letting it stand for 15 minutes, baking it at 230°C for 20 minutes, and curing it. Then, the light-functional layer mixture is sprayed onto the surface of the base layer according to the method of scheme 5 in embodiment 2, letting it stand for 20 minutes, baking it at 230°C for 20 minutes, and curing it. Finally, the top hydrophobic protective layer mixture is sprayed onto the surface of the light-functional layer according to the method of scheme 3 in embodiment 3, letting it stand for 20 minutes, and baking it at 230°C for 20 minutes to form the top hydrophobic protective layer.

[0301] The reflectivity and emissivity of the graded metamaterial structure coatings assembled in Examples 4-20 and Comparative Examples 1-6 after the cooling window are shown in Table 1 below.

[0302] Table 1 - Reflectivity and emissivity of the cooling window assembled from hierarchical metamaterial structure coatings in different embodiments

[0303]

[0304]

[0305]

[0306] The table above shows the transparent window interlayer and the light green tempered glass window interlayer, indicating that... Figure 2 As shown, the blinds are located between the first and second panes of glass; the outer side of the transparent glass window and the outer side of the light green tempered glass window indicate... Figure 3 As shown, the blinds are located on the side of the second glass.

[0307] A comparison of Examples 4-6 with Comparative Examples 3-5 shows that Examples 4, 5, and 6, with their internal particles graded and adjusted, exhibit significantly higher reflectivity than Comparative Examples 3, 4, and 5, which are ungraded or have minimal grading. This demonstrates that the graded coating possesses stronger solar radiation reflection capability, i.e., greater potential for regulating indoor temperature. Furthermore, comparing Examples 4 with Examples 5 and 6 reveals that, in addition to graded control of particle size, adjusting the mass fraction of particles at different thickness positions can further enhance the coating's reflectivity.

[0308] As can be seen from Examples 7-18 and Comparative Examples 6 and 7, adding appropriate inorganic scattering particles to the bottom layer and the top hydrophobic protective layer can further improve the overall reflection efficiency, with the highest reflectivity reaching over 96%. Examples 17 and Comparative Example 8 show that regardless of whether the blinds are installed within the glass interlayer or on the outside of the window, they can achieve high solar reflectance and mid-infrared emission characteristics, meaning their function of regulating indoor temperature remains intact. Examples 19 and Comparative Example 9 show that when the glass is colored, its reflectance characteristics are basically unaffected, indicating the wide applicability of this blind in various scenarios.

[0309] Two guard booths, each 2m high and 1m wide and long, were used as experimental subjects to verify the effectiveness of the louvers. Both booths had only one south-facing window measuring 1m × 0.8m. One booth used ordinary aluminum louvers as described in Comparative Example 2, without a tiered structure. The other booth used louvers with a tiered metamaterial structure coating as described in Example 20 of this invention. Both louvers were fully closed. The room temperature inside the booths with the two types of louvers was recorded during the period of strongest sunlight, from 11:00 am to 2:30 pm. The results are as follows: Figure 5 As shown, Figure 5 The ambient temperature refers to the temperature outside the guard post. Figure 5 As can be seen, compared with the indoor temperature of the guard booth using ordinary louvers, the indoor temperature of the guard booth using louvers with graded structure coating is reduced by about 8.05℃, indicating that the graded structure coating has a more obvious cooling effect.

[0310] Figure 6 The cross-sectional SEM image of the hierarchical metamaterial structure coating observed using Example 17 as a sample, as well as the Ti element distribution along the interface direction, shows that the Ti element content exhibits obvious hierarchical characteristics in the coating thickness, proving that the hierarchical metamaterial structure mentioned in this invention can be stably prepared and applied.

[0311] Furthermore, performance tests were conducted on the graded metamaterial structure coating in Example 17, and the results are as follows: According to GB / T9286-2021, the cross-cut adhesion test showed an adhesion grade of 1; according to HGT 4341-2012, the impact resistance test showed no wrinkles, cracks, or peeling after an impact from a 1kg hammer at a height of 50cm; according to GB / T 9755-2014, the wash resistance test showed no damage to the paint film after 5000 washes; according to GB / T 10125-2021, the acid salt spray test showed no red rust on the surface after 200 hours of acetic acid salt spray; according to HG / T 4341-2012, the acid resistance test showed no abnormalities after 168 hours of immersion in 5% sulfuric acid solution; according to GB / T... Based on GB / T 9755-2014, alkali resistance testing was conducted, and no abnormalities were observed after 48 hours of immersion in a saturated NaOH solution. Artificial climate aging was performed according to GB / T 9755-2014, with 1000W solar spectrum irradiation (including 60W 300-400nm ultraviolet irradiation), and no bubbles or cracks were observed after 2000 hours of artificial climate aging. This meets the requirements for long-term window use.

[0312] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The embodiments described above only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A high-radiation-resistant cooling window with a graded metamaterial structure coating, characterized in that, The high-radiation-resistant cooling window includes: a first glass pane, a second glass pane, louvers, and two window frames; The first combination of the high-radiation cooling window is a first glass, a second glass, a louver, and two window frames. The first glass and the second glass are spaced apart, and the louver is located between the first glass and the second glass. The first glass, the second glass, and the louver are all fixed between the two window frames. The second combination of the high-radiation cooling window is a first glass, a second glass, a louver, and two window frames. The first glass and the second glass are spaced apart, the louver is located outside the second glass or the first glass, and the first glass, the second glass, and the louver are all fixed between the two window frames. The surface of the louvers or window frames is integrated with at least one graded metamaterial structure coating. The hierarchical metamaterial structure coating comprises a bottom layer, a light-functional layer with a micro-hierarchical micro-nano structure, and a hydrophobic protective layer stacked sequentially. The optical functional layer with micro-hierarchical micro-nano structure includes a first polymer and a first high-refractive-index inorganic spectral particle filler. The first polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin; The first high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate. The first high-refractive-index inorganic spectral particle filler has a mass fraction of 20-50% in the optical functional layer; The particle size of the first high-refractive-index inorganic spectral particle filler is 10 nm to 5000 nm; Inside the optical functional layer with micro-hierarchical micro-nano structure, the size of the first high-refractive-index inorganic spectral particle filler is distributed in the thickness direction according to a pattern of decreasing size or increasing size. Alternatively, within the optical functional layer with micro-hierarchical micro / nano structure, the volume fraction of the first high-refractive-index inorganic spectral particle filler is distributed in a pattern from large to small or from small to large along its thickness direction.

2. The high-radiation-resistant cooling window with a graded metamaterial structure coating as described in claim 1, characterized in that, One surface of the bottom layer is attached to the surface of the window frame or louver blades, and the other surface is attached to the light functional layer of the micro-hierarchical micro-nano structure. The bottom layer comprises a second polymer and functional fillers; The second polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin; The functional fillers include corrosion-resistant fillers and second high-refractive-index inorganic spectral particle fillers; The corrosion-resistant filler includes at least one of zinc powder, sodium hexaphosphate, ferric oxide, zinc phosphate, and aluminum tripolyphosphate; The second high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate.

3. The high-radiation-resistant cooling window with a graded metamaterial structure coating as described in claim 2, characterized in that, The hydrophobic protective layer of the cover includes a third high molecular polymer and hydrophobic filler, and a third high refractive index inorganic spectral particle filler. The third polymer includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, acrylic resin, epoxy resin, polyurethane, polyester resin, vinyl resin and silicone resin; The hydrophobic filler includes at least one of silane coupling agent, organosilicon resin, and nano-silica. The third high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide, silicon dioxide, barium sulfate, aluminum oxide, zinc oxide, silicon carbide, zinc sulfide, boron nitride, magnesium oxide, barium carbonate, and aluminum silicate. The third high-refractive-index inorganic spectral particle filler has a mass fraction of 5-10% in the hydrophobic protective layer of the cover; The thickness of the optical functional layer of the micro-hierarchical micro / nano structure is 50 μm to 200 μm; The thickness of the bottom layer is 10μm to 100μm; The particle size of the second high-refractive-index inorganic spectral particle filler in the bottom layer is 10 nm to 5000 nm; The particle size of the corrosion-resistant filler is 200nm to 5000nm; The thickness of the hydrophobic protective layer on the surface is 5μm to 100μm; The particle size of the third high-refractive-index inorganic spectral particle filler in the hydrophobic protective layer of the cover is 10 nm to 5000 nm.

4. The high-radiation-resistant cooling window with a graded metamaterial structure coating as described in claim 2, characterized in that, The bottom layer, the optical functional layer with micro-hierarchical micro-nano structure, and the hydrophobic protective layer also include a diluent, which is xylene. The bottom layer comprises a second polymer and a xylene diluent. The second polymer comprises a fluoropolymer and an acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin and xylene is (15-20):(5-10):(25-35). Alternatively, the bottom layer comprises a second polymer, an anti-corrosion filler, and xylene. The second polymer comprises fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin, xylene, and anti-corrosion filler is (15-20):(5-10):(25-40):(60-75). The anti-corrosion filler is zinc powder, and the particle size of the anti-corrosion filler is 200nm-5000nm. Alternatively, the bottom layer includes a second polymer, an anti-corrosion filler, xylene, and a second high-refractive-index inorganic spectral particle filler. The second polymer includes fluoropolymer and acrylic resin. The mass ratio of the fluoropolymer, acrylic resin, xylene, anti-corrosion filler, and second high-refractive-index inorganic spectral particle filler is (15-20):(5-10):(25-40):(60-75):(5-10). The second high-refractive-index inorganic spectral particle filler is titanium dioxide, and the particle size of the second high-refractive-index inorganic spectral particle filler is 100nm-500nm.

5. The high-radiation-resistant cooling window with a graded metamaterial structure coating as described in claim 1, characterized in that, The optical functional layer with micro-hierarchical micro / nano structure includes multiple superimposed sub-optical functional layers. Each sub-optical functional layer includes a first polymer, a first high-refractive-index inorganic spectral particle filler, and xylene. The first polymer includes fluoropolymer and acrylic resin. The particle size and mass ratio of the first high-refractive-index inorganic spectral particle filler are different in different sub-optical functional layers. The first high-refractive-index inorganic spectral particle filler includes at least one of titanium dioxide with a particle size of 100nm to 500nm, titanium dioxide with a particle size of 500nm to 800nm, and titanium dioxide with a particle size of 800nm ​​to 1400nm. The mass ratio of the fluororesin, acrylic resin, xylene, and the first high-refractive-index inorganic spectral particle filler is (55-65):(15-25):(60-70):(10-80).

6. The high-radiation-resistant cooling window with a graded metamaterial structure coating as described in claim 1, characterized in that, The hydrophobic protective layer comprises a third polymer and xylene. The third polymer comprises fluoropolymer and acrylic resin. The mass ratio of the fluoropolymer, acrylic resin, xylene, and hydrophobic filler is (55-65):(15-25):(70-80):(10-25). Alternatively, the hydrophobic protective layer may comprise a third polymer, xylene, and a third high-refractive-index inorganic spectral particle filler. The third polymer may comprise fluoropolymer and acrylic resin, and the mass ratio of the fluoropolymer, acrylic resin, xylene, and the third high-refractive-index inorganic spectral particle filler may be (55–65):(15–25):(70–80):(10–25):(15–20). The third high-refractive-index inorganic spectral particle filler may be alumina with a diameter of 100 nm to 300 nm.

7. The high-radiation-resistant cooling window with a graded metamaterial structure coating as described in claim 1, characterized in that, The optical functional layer with micro-hierarchical micro-nano structure consists of two sub-optical functional layers from bottom to top: a bottom optical functional layer and an upper optical functional layer. The first high-refractive-index inorganic spectral particle filler in the upper optical functional layer is titanium dioxide with a particle size of 100nm to 500nm. The first high-refractive-index inorganic spectral particle filler in the bottom optical functional layer is titanium dioxide with a particle size of 500nm to 800nm; Alternatively, the optical functional layer with micro-hierarchical micro / nano structure may include three sub-optical functional layers from bottom to top: an upper optical functional layer, a middle optical functional layer, and a bottom optical functional layer. The first high-refractive-index inorganic spectral particle filler in the upper optical functional layer is titanium dioxide with a particle size of 100nm to 500nm; The first high-refractive-index inorganic spectral particle filler in the middle optical functional layer is titanium dioxide with a particle size of 500nm to 800nm; The first high-refractive-index inorganic spectral particle filler in the bottom optical functional layer is titanium dioxide with a particle size of 800nm ​​to 1400nm; Alternatively, the first high-refractive-index inorganic spectral particle filler in the optical functional layer comprises a mixture of titanium dioxide with a mass ratio of (3-7):(1-3):(1-3) and particle sizes of 100nm-500nm, 500nm-800nm, and 800nm-1400nm, respectively.

8. A method for preparing a high-radiation-resistant cooling window with a hierarchical metamaterial structure coating as described in any one of claims 1 to 7, comprising the following steps: By installing the first glass, the second glass, and the louvers between the outer frame of the window, a cooling window with a high-radiation-resistant coating and a graded metamaterial structure is obtained. The louvers or window frames are all integrated with at least one graded metamaterial structure coating. The method for preparing the hierarchical metamaterial structure coating includes the following steps: The second high-refractive-index inorganic spectral particle filler, anti-corrosion filler, and diluent are added to the second polymer and stirred to obtain the bottom mixture. Apply the base coat mixture to the surface of the window frame or louver slats to form the base coat; First high-refractive-index inorganic spectral particle fillers and diluents with different physical properties are added to first polymer and stirred to obtain multiple spectral functional mixtures. Multiple spectral functional mixtures are sequentially coated onto the surface of the base layer to form a light functional layer with a micro-nano structure. The third high refractive index inorganic spectral particle filler, hydrophobic filler, and diluent are added to the third high molecular polymer and stirred to obtain the hydrophobic protective layer mixture. A mixture of hydrophobic protective layer materials is coated onto the surface of an optical functional layer with a micro-hierarchical micro-nano structure to form a hydrophobic protective layer.

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