Temperature-adaptive radiation temperature control film and preparation method thereof

Abstract

The invention relates to the technical field of radiation refrigeration. The invention provides a temperature self-adaptive radiation temperature control film and a preparation method thereof, the temperature self-adaptive radiation temperature control film comprises a functional layer and a protective layer arranged on the upper side of the functional layer, the functional layer comprises a plurality of micro-units arranged in an array, the projection of each micro-unit on the protective layer is a polygon, the micro-units are provided with through holes along the vertical direction in a penetrating manner, and the through holes are communicated with the protective layer. The minimum distance between the vertexes of the two polygons formed by the two adjacent micro units is d1, the distance between the midpoints of the edges of the two polygons formed by the two adjacent micro units is d2, d1 is smaller than d2, and the micro units are made of vanadium dioxide. The temperature self-adaptive radiation temperature control film provided by the invention is low in cost, the thermal radiation rate can change along with the temperature, and the modulation depth of the thermal radiation rate is large.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radiation refrigeration, in particular to a temperature-adaptive radiation temperature control film and a preparation method thereof. BACKGROUND

[0002] For many years, researchers have been working on developing radiation refrigeration materials to passively reduce the temperature of objects. The most typical example is radiation refrigeration roof materials used to reduce the energy consumption of building air conditioning refrigeration. In order to maximize the efficiency of building radiation refrigeration, these materials generally have very low solar absorption and very high thermal infrared emissivity. However, these traditional radiation refrigeration materials continue to emit heat externally in low-temperature environments, causing overcooling of buildings on cold nights or in winter, resulting in additional heating system energy consumption. In areas with large diurnal temperature differences or low average annual temperatures, this part of the additional heating system energy consumption may even offset the energy-saving amount of the refrigeration system.

[0003] In order to solve the problem of overcooling in low-temperature environments for radiation refrigeration materials, a temperature-adaptive radiation temperature control film was proposed and passed field tests in 2021. The temperature-adaptive radiation temperature control film integrates vanadium dioxide, a thermosensitive phase change material, inside. Its thermal infrared emissivity can automatically follow the temperature change of the film: when the temperature of the film is higher than the phase transition temperature of vanadium dioxide, the temperature-adaptive radiation temperature control film has a very high thermal infrared emissivity, acting as a passive refrigeration; when the temperature of the film is lower than the phase transition temperature of vanadium dioxide, the temperature-adaptive radiation temperature control film has a very low thermal infrared emissivity, acting as a passive heating. According to calculations, in most temperate and subtropical regions of the world, the temperature-adaptive radiation temperature control film saves more energy than all existing building exterior materials.

[0004] However, the temperature-adaptive radiation temperature control film of 2021 has problems such as high production cost, inability to mass-produce, and limited service life. In 2023, a temperature-adaptive radiation temperature control film based on roll-to-roll manufacturing was developed to solve the above problems. However, this film still cannot be put into practical application due to its high cost, low modulation depth of thermal emissivity (i.e., the difference in thermal infrared emissivity between the high-temperature refrigeration and low-temperature heating modes), and limited range of solar absorption control. SUMMARY

[0005] The present application aims to at least partially solve one of the technical problems in the related art. To this end, one object of the present application is to provide a temperature-adaptive radiation temperature control film with low cost and large thermal emissivity modulation depth.

[0006] To this end, the present application provides, in a first aspect, a temperature-adaptive radiation temperature control film, comprising a functional layer and a protective layer arranged on the upper side of the functional layer, wherein:

[0007] The functional layer comprises a plurality of micro-units arranged in an array, each micro-unit has a polygonal projection on the protective layer, the micro-units are provided with through holes along the up-down direction, the minimum distance between the vertices of two polygons formed by two adjacent micro-units is d1, the distance between the midpoints of the edges of the two polygons formed by two adjacent micro-units is d2, and d1 < d2, and the material of the micro-units comprises vanadium dioxide.

[0008] In the embodiment of the present application, the functional layer comprises a plurality of micro-units arranged in an array, each micro-unit has a polygonal projection on the protective layer, the micro-units are provided with through holes along the up-down direction, the minimum distance between the vertices of two polygons formed by two adjacent micro-units is d1, the distance between the midpoints of the edges of the two polygons formed by two adjacent micro-units is d2, and d1 < d2, thereby, compared with the existing arrangement mode, the present application forms an "angle-to-angle" arrangement mode of two adjacent micro-units, and the micro-units are provided with through holes along the up-down direction to form a hollow structure, forming a high-loss antenna structure, compared with the parallel conductive plate structure formed by the existing arrangement mode, the electric field is enhanced, a stronger electric field enhancement effect is achieved with less vanadium dioxide, the enhanced electric field leads to a higher electric field loss rate, thereby achieving a higher infrared thermal emissivity under high temperature. At the same time, a plurality of different high-loss antenna structures exist in the array, and the electric field is enhanced at different wavelengths. Therefore, compared with the prior art, the present application can achieve a high thermal infrared emissivity in a larger wavelength range under high temperature. In addition, the through holes reduce the coverage of vanadium dioxide, thereby achieving a lower thermal infrared emissivity under low temperature. Research shows that in the wavelength range of 8 μm to 13 μm, the thermal infrared emissivity of the temperature self-adaptive radiation temperature control film of the present application under high temperature is increased by more than 30%, and the thermal infrared emissivity under low temperature is reduced by more than 30%, the modulation depth of the thermal infrared emissivity is greatly improved, which helps to greatly reduce the total annual energy consumption of the cold and warm temperature control system; in addition, the through holes save the amount of vanadium dioxide and reduce the cost, which is more suitable for large-scale production.

[0009] In some embodiments of the present application, the vanadium dioxide comprises a doping element, and the doping element comprises at least one of chromium, tungsten, gallium, aluminum, iron, titanium, niobium, molybdenum, rhenium, fluorine and hydrogen. Adding the above-mentioned doping elements to vanadium dioxide can control the phase transition temperature of vanadium dioxide, which helps to improve the total annual energy saving amount of the temperature self-adaptive radiation temperature control film.

[0010] In some embodiments of the present application, the atomic number of the doping element accounts for 0-10% of the atomic number of vanadium in the vanadium dioxide. Adding the above-mentioned content of the doping element in the vanadium dioxide can control the phase transition temperature of the vanadium dioxide, and help to improve the total annual energy saving amount of the temperature self-adaptive radiation temperature control film.

[0011] In some embodiments of the present application, the projection of the micro-unit on the protective layer is a triangle, a quadrilateral or a hexagon; and / or the thickness of each micro-unit is 0.1-3 μm. The modulation depth of the thermal infrared emissivity of the temperature self-adaptive radiation temperature control film can be improved.

[0012] In some embodiments of the present application, the projection of the micro-unit on the protective layer is a triangle, a quadrilateral or a hexagon, and the side length of the triangle, the quadrilateral or the hexagon is 1-6 μm.

[0013] Optionally, a plurality of the micro-units are arranged at intervals along the length direction and the width direction of the functional layer, and the included angle between any one side of the quadrilateral and the length direction of the functional layer is 35-55°.

[0014] Optionally, a plurality of the micro-units are arranged at intervals along the length direction and the width direction of the functional layer, and the micro-unit array forms a two-dimensional triangular lattice. The two-dimensional triangular lattice is a lattice formed by periodically and closely arranging equilateral triangles. The minimum included angle between the side of the triangle and the length direction of the functional layer is -10-10°.

[0015] Optionally, a plurality of the micro-units are arranged at intervals along the length direction and the width direction of the functional layer, and the micro-unit array forms a two-dimensional triangular lattice. The two-dimensional triangular lattice is a lattice formed by periodically and closely arranging equilateral triangles. The minimum included angle between the side of the hexagon and the length direction of the functional layer is -10-10°.

[0016] Optionally, the projections of any two micro-units on the protective layer both have a first vertex, and the distance between the two first vertices is 3-10 μm. The modulation depth of the thermal infrared emissivity of the temperature self-adaptive radiation temperature control film can be improved.

[0017] In some embodiments of the present application, the temperature self-adaptive radiation temperature control film further comprises a reflective layer arranged on the lower side of the functional layer, and the material of the reflective layer comprises at least one of aluminum, silver, gold, chromium, nickel, platinum, tin and titanium; or the temperature self-adaptive radiation temperature control film further comprises a reflective layer arranged on the lower side of the functional layer, and the material of the reflective layer comprises at least one of indium tin oxide, zinc aluminum oxide, gallium-doped zinc oxide, graphene, carbon nanotube, metal nanowire, metal mesh, conductive polymer and low-emissivity glass. The modulation depth of the thermal infrared emissivity of the temperature self-adaptive radiation temperature control film can be improved.

[0018] In some embodiments of the present invention, the protective layer is made of a permeable material, which includes at least one selected from polyethylene, colored polyethylene, EPDM rubber, polytetrafluoroethylene, polymethylpentene, MXene, hafnium oxide, magnesium fluoride, barium fluoride, and calcium fluoride. This can improve the modulation depth of the thermal infrared emissivity of the temperature-adaptive radiation-controlled film and increase its service life.

[0019] In some embodiments of the present invention, the protective layer further includes an infrared transparent pigment, which comprises at least one of Prussian blue, zinc oxide, zinc selenide, zinc sulfide, barium fluoride, calcium fluoride, magnesium fluoride, ferric oxide, chromium oxide, silicon, and germanium. The solar absorption rate of the temperature-adaptive radiation-controlled film can be adjusted to increase the total annual energy savings; its appearance color can also be changed to meet application requirements.

[0020] In some embodiments of the present invention, the protective layer includes a first protective layer disposed above the functional layer and a second protective layer disposed above the first protective layer, wherein one of the first protective layer and the second protective layer includes the transmissive material, and the other includes the infrared transparent pigment. The solar absorption rate of the temperature-adaptive radiation-controlled film can be adjusted to increase the total annual energy savings; its appearance color can also be changed to meet application requirements.

[0021] A second aspect of the present invention provides a method for preparing the temperature-adaptive radiation-controlled thin film described in the first aspect, comprising:

[0022] A functional layer is prepared, the functional layer comprising a plurality of micro-units arranged in an array, each micro-unit having a polygonal projection on the protective layer, the micro-unit having a through hole extending vertically, the minimum distance between the vertices of the two polygons formed by two adjacent micro-units being d1, the distance between the midpoints of the sides of the two polygons formed by two adjacent micro-units being d2, d1 < d2, and the material of the micro-units including vanadium dioxide.

[0023] A protective layer is prepared on the upper side of the functional layer to obtain a temperature-adaptive radiation-controlled film.

[0024] Therefore, the prepared temperature-adaptive radiation-controlled film can achieve a greater infrared thermal emissivity modulation depth over a wider wavelength range, losing 30% less energy at low temperatures and releasing 30% more energy at high temperatures compared to existing technologies; the solar absorption rate is reduced by about 50%, making it more suitable for use as a transparent coating that can be applied to glass surfaces; and the amount of vanadium dioxide used is reduced by about 50%, which is more conducive to cost savings.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0027] Figure 1 A schematic diagram (side view) of the structure of the temperature-adaptive radiation temperature control film of Embodiment 2 of the present invention is shown;

[0028] Figure 2 This shows a top view of the functional layer of the temperature-adaptive radiation-controlled film of Embodiment 2 of the present invention;

[0029] Figure 3 This shows a top view of the existing functional layers in Comparative Example 1;

[0030] Figure 4 The graph shows the relationship between the total annual additional energy savings and solar absorptivity of the temperature-adaptive radiation-controlled film in Seattle for Example 4 and Comparative Example 1.

[0031] Figure 5 A schematic diagram of the structure of a temperature-adaptive radiation-controlled film according to another embodiment (Example 3) of the present invention is shown;

[0032] Figure 6 This shows a top view of the functional layer of a temperature-adaptive radiation-controlled film according to another embodiment (Example 3) of the present invention;

[0033] Figure 7 This shows a top view of the functional layer of a temperature-adaptive radiation-controlled film according to another embodiment (Example 4) of the present invention;

[0034] Figure 8 The thermal infrared emissivity spectra of the temperature-adaptive radiation-controlled thin films of Embodiment 1 and Comparative Example 1 of the present invention, affixed to low-emissivity glass, are shown at different temperatures.

[0035] Figure 9 The diagram shows the radiation loss rate distribution (top view) of the temperature-adaptive radiation-controlled thin film of Embodiment 2 and Comparative Example 1 at a wavelength of 9 μm.

[0036] Figure 10 The diagram shows the radiation loss rate distribution of the temperature-adaptive radiation-controlled film of Embodiment 2 of the present invention at wavelengths of 9 μm and 12 μm (top view);

[0037] Figure 11The thermal infrared emissivity spectra of the temperature-adaptive radiation-controlled films of Embodiment 2 and Comparative Example 1 of the present invention at different temperatures are shown.

[0038] Figure 12 The diagram shows the radiation loss rate distribution of the temperature-adaptive radiation-controlled film of Embodiment 3 of the present invention at wavelengths of 9 μm and 12 μm (top view);

[0039] Figure 13 The thermal infrared emissivity spectra of the temperature-adaptive radiation-controlled films of Embodiment 3 and Comparative Example 1 of the present invention at different temperatures are shown.

[0040] Figure 14 The diagram shows the radiation loss rate distribution of the temperature-adaptive radiation-controlled film of Embodiment 4 of the present invention at wavelengths of 9 μm and 12 μm (top view);

[0041] Figure 15 The thermal infrared emissivity spectra of the temperature-adaptive radiation-controlled films of Embodiment 4 and Comparative Example 1 of the present invention are shown at different temperatures.

[0042] Reference numerals: 1: Protective layer; 11: Protective layer a; 12: Protective layer b; 13: Protective layer c; 2: Functional layer; 21: Micro-unit; 211: Through-hole; 3: Reflective layer. Detailed Implementation

[0043] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0044] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0045] Please see Figure 1 and Figure 2 This invention proposes a temperature-adaptive radiation-controlled film, comprising a functional layer 2 and a protective layer 1 disposed on the upper side of the functional layer 2. The functional layer 2 includes a plurality of micro-units 21 arranged in an array. The projection of each micro-unit 21 onto the protective layer 1 is a polygon. Each micro-unit 21 has a through hole 211 extending vertically. The minimum distance between the vertices of the two polygons formed by two adjacent micro-units 21 is d1, and the distance between the midpoints of the sides of the two polygons formed by two adjacent micro-units 21 is d2, where d1 < d2. The material of the micro-units 21 includes vanadium dioxide.

[0046] It can be understood that the two polygons formed by two adjacent micro-units 21 refer to the two polygons formed by the orthographic projection (i.e., the projection along the vertical direction) of the two adjacent micro-units 21 on the protective layer 1.

[0047] In this embodiment of the invention, the functional layer 2 includes a plurality of micro-units 21 arranged in an array. The projection of each micro-unit 21 onto the protective layer 1 is a polygon. Each micro-unit 21 has a through-hole 211 extending vertically. The minimum distance between the vertices of the two polygons formed by two adjacent micro-units 21 is d1, and the distance between the midpoints of the sides of the two polygons formed by two adjacent micro-units 21 is d2, where d1 < d2. Thus, compared to existing arrangements, this application forms a "corner-to-corner" arrangement of adjacent micro-units 21, and the through-hole 211 in the vertical direction creates a hollow structure, forming a high-loss antenna structure. Compared to the parallel conductive plate structure formed by existing arrangements, the high-loss antenna structure achieves a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, thereby achieving a higher thermal infrared emissivity at high temperatures. Simultaneously, the array contains multiple different high-loss antenna structures, enabling absorption of infrared light at different wavelengths. Therefore, compared to existing technologies, this application achieves a higher infrared thermal emissivity (>0.8) over a wider wavelength range at high temperatures. Furthermore, the via 211 reduces the vanadium dioxide coverage, resulting in even lower thermal infrared emissivity at low temperatures. Studies show that within the wavelength range of 8μm to 13μm, the temperature-adaptive radiation-controlled film of this application increases the thermal infrared emissivity by more than 30% at high temperatures and decreases it by more than 30% at low temperatures, significantly improving the modulation depth of thermal infrared emissivity and saving more energy for building heating and cooling systems. Moreover, the via 211 reduces the amount of vanadium dioxide used, lowering costs and making it more suitable for large-scale production.

[0048] In summary, the temperature-adaptive radiation-controlled film proposed in this application can achieve a greater depth of thermal infrared emissivity regulation over a wider wavelength range. The high-temperature thermal infrared emissivity of this film is increased by more than 30%, while the low-temperature thermal infrared emissivity is reduced by more than 30%, saving more energy for building heating and cooling systems. The solar absorption rate is reduced by about 50%, making it more suitable for use as a transparent coating that can be adhered to glass surfaces. Furthermore, the amount of vanadium dioxide used is reduced by about 50%, further contributing to cost savings.

[0049] It is understood that this invention uses vanadium dioxide to fabricate a metamaterial with modulated thermal infrared emissivity. Therefore, the change in the infrared optical complex refractive index of vanadium dioxide during its thermosensitive phase transition can be utilized to alter the thermal infrared emissivity of the temperature-adaptive radiation-controlled film in the 8μm–13μm wavelength range. In high-temperature environments, the vanadium dioxide inside the functional layer 2 is in a metallic state, giving it a high thermal infrared emissivity and thus a passive cooling effect. In low-temperature environments, the vanadium dioxide inside the functional layer 2 is in an insulating state, giving it a low thermal infrared emissivity and thus a passive warming effect. Since the phase transition temperature of vanadium dioxide can be adjusted by the type and concentration of doping elements, the cooling-warming mode transition temperature of the temperature-adaptive radiation-controlled film can be freely designed. The hollow-patterned vanadium dioxide metamaterial has advantages such as high thermal infrared emissivity in cooling mode, low thermal infrared emissivity in warming mode, low solar absorption rate, and low vanadium dioxide usage, which helps improve the passive temperature control performance of the temperature-adaptive radiation-controlled film and reduce production costs.

[0050] This invention has the advantages of being mass-producible, low cost, thermal infrared emissivity varying with temperature, large thermal infrared emissivity modulation depth, and adjustable temperature for switching between cooling and heating modes. It can stabilize the temperature of buildings, vehicles, clothing, and spacecraft with zero power consumption, and reduce the operating energy consumption of heating and cooling temperature control systems.

[0051] Understandably, please refer to Figure 2 and Figure 3 , Figure 2 for Figure 1 The top view of functional layer 2 is also the projection of the micro-units 21 of functional layer 2 onto protective layer 1. d1 < d2, so that the two vertices of the projections formed by two adjacent micro-units 21 on protective layer 1 are as close as possible, achieving "corner-to-corner" ( Figure 2 ), rather than "edge-to-edge" ( Figure 3 Thus, a "corner-to-corner" arrangement realizes one type of high-loss antenna, while a hollow center (the through-hole 211) realizes another type of high-loss antenna structure. The array contains multiple different high-loss antenna structures, allowing for absorption of infrared light at different wavelengths. Therefore, compared to existing technologies, this application achieves high thermal infrared emissivity over a wider wavelength range at high temperatures.

[0052] It is understandable that during the actual fabrication of the micro-unit 21 of functional layer 2, due to the possibility of etching or other operations during the fabrication process, or due to errors in the fabrication instrument, two adjacent micro-units 21 may have vertices connected together. In this case, the minimum distance d1 between the vertices of the two polygons formed may be 0 or negative. This situation should also be within the scope of protection of this application.

[0053] In some embodiments of the present invention, the vanadium dioxide includes a dopant element, which includes at least one selected from chromium, tungsten, gallium, aluminum, iron, titanium, niobium, molybdenum, rhenium, fluorine, and hydrogen. By doping vanadium dioxide with the above-mentioned dopant elements, the phase transition temperature of vanadium dioxide can be adjusted as needed, thereby adjusting the cooling-heating mode transition temperature of the temperature-adaptive radiation temperature-controlled thin film to meet the needs of different regions or applications, allowing for targeted doping of different elements according to requirements.

[0054] In high-temperature environments, the vanadium dioxide or vanadium dioxide doped with other elements inside the functional layer 2 is in a metallic state, giving the functional layer 2 a high thermal infrared emissivity and achieving a passive cooling effect; in low-temperature environments, the vanadium dioxide or vanadium dioxide doped with other elements inside the functional layer 2 is in an insulating state, giving the functional layer 2 a low thermal infrared emissivity and achieving a passive warming effect.

[0055] In some embodiments of the present invention, the number of atoms of the dopant element accounts for 0 to 10% of the number of vanadium atoms in vanadium dioxide. For example, the number of atoms of the dopant element accounts for 0 to 9.9%, 0.5% to 9.5%, 1% to 9%, 2% to 8%, 3% to 7%, 4% to 6%, etc., of the number of vanadium atoms in vanadium dioxide. By doping vanadium dioxide with the above-mentioned amounts of dopant element, the phase transition temperature of vanadium dioxide can be adjusted as needed, and the cooling-heating mode transition temperature of the temperature adaptive radiation temperature control film can be adjusted as needed to adapt to the needs of different regions or different applications. Different amounts of dopant element can be selectively doped according to requirements.

[0056] In some embodiments of the present invention, the projection of the micro-unit 21 onto the protective layer 1 is a triangle, quadrilateral, or hexagon. This facilitates the formation of a "corner-to-corner" arrangement between adjacent micro-units 21. Furthermore, the micro-unit 21 has through-holes 211 extending vertically to form a hollow structure, resulting in a high-loss antenna structure. This is superior to the parallel conductive plate structure formed by existing arrangements. Figure 3This invention achieves enhanced electric field using less vanadium dioxide, resulting in a stronger electric field enhancement effect. The enhanced electric field leads to a higher electric field loss rate, thereby achieving higher thermal infrared emissivity at high temperatures. Simultaneously, the array contains multiple different high-loss antenna structures, allowing for absorption of infrared light at different wavelengths. Therefore, compared to existing technologies, this application achieves high infrared thermal emissivity over a wider wavelength range at high temperatures. Research shows that within the wavelength range of 8μm to 13μm, the high-temperature thermal infrared emissivity of the temperature-adaptive radiation-controlled film of this application is increased by more than 30%, while the low-temperature thermal infrared emissivity is reduced by more than 30%. The modulation depth of thermal infrared emissivity is significantly improved, which helps to significantly reduce the total annual energy consumption of the heating and cooling temperature control system.

[0057] In some embodiments of the present invention, the thickness of each micro-unit 21 is 0.1 μm to 3 μm. For example, the thickness of each micro-unit 21 can be 0.1 μm to 2.9 μm, 0.5 μm to 2.5 μm, 0.8 μm to 2.3 μm, 1 μm to 2 μm, 1.5 μm to 2 μm, etc. It can be understood that the thickness of the micro-unit 21 is the dimension of the micro-unit 21 in the vertical direction. Controlling the thickness of the micro-unit 21 within the above range facilitates the formation of a high-loss antenna structure, realizes the enhancement of the electric field, and achieves a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, thereby achieving a higher infrared absorption rate at high temperatures.

[0058] In some embodiments of the present invention, the projection of the micro-unit 21 onto the protective layer 1 is a triangle, quadrilateral, or hexagon, and the side length of the triangle, quadrilateral, or hexagon is 1μm to 6μm. For example, the side length of the triangle, quadrilateral, and / or hexagon can be 1μm to 5.9μm, 1.5μm to 4.5μm, 2μm to 4μm, 2.5μm to 3.5μm, 3μm to 3.5μm, etc. Controlling the side length of the polygon (triangle, quadrilateral, or hexagon) within the above range facilitates the formation of a high-loss antenna structure, realizes the enhancement of the electric field, and achieves a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, thereby achieving a higher infrared absorption rate at high temperatures.

[0059] It is understood that as long as the side length of any side of the polygon is within the scope of this application, it is within the protection scope of this application. In some other embodiments of the present invention, the projection of the micro-unit 21 on the protective layer 1 is a square.

[0060] In some embodiments of the present invention, a plurality of micro-units 21 are arranged at intervals along the length and width directions of the functional layer 2. The angle between any side of the quadrilateral and the length direction of the functional layer 2 is 35° to 55°. For example, the angle between any side of the quadrilateral and the length direction of the functional layer 2 can be 40° to 49°, 41° to 48°, 42° to 47°, 43° to 46°, 44° to 45°, etc. For details, please refer to [link to relevant documentation]. Figure 2 The angle between any side of the quadrilateral and the length direction of the functional layer 2 is α, where α is the corresponding acute angle. Controlling α within the aforementioned range facilitates the formation of a "corner-to-corner" arrangement between adjacent micro-units 21. Furthermore, the micro-units 21 have through-holes 211 running vertically to form a hollow structure, creating a high-loss antenna structure. Compared to the parallel conductive plate structure formed by existing arrangements, this arrangement enhances the electric field, achieving a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, resulting in higher infrared absorption at high temperatures. Simultaneously, the array contains multiple different high-loss antenna structures, allowing for absorption of infrared light at different wavelengths. Therefore, compared to existing technologies, this application achieves a higher infrared thermal emissivity over a wider wavelength range at high temperatures. Studies have shown that, within the wavelength range of 8μm to 13μm, the temperature-adaptive radiation-controlled film of this application exhibits a higher high-temperature thermal infrared emissivity by more than 30%, while a lower low-temperature thermal infrared emissivity by more than 30%. The modulation depth of the thermal infrared emissivity is significantly improved, which helps to substantially reduce the total annual energy consumption of the heating and cooling temperature control system.

[0061] In some embodiments of the present invention, a plurality of micro-units 21 are arranged at intervals along the length and width directions of the functional layer 2, and the micro-unit array forms a two-dimensional triangular lattice. The two-dimensional triangular lattice is a lattice formed by periodically and closely arranged equilateral triangles. The minimum angle α between the side of the triangle and the length direction of the functional layer 2 is -10° to 10°. For example, the minimum angle α between the side of the triangle and the length direction of the functional layer 2 can be -10° to 9°, -6° to 6°, -5° to 5°, -2° to 2°, etc. Specifically, controlling the minimum angle between the side of the triangle and the length direction of the functional layer 2 within the above range is beneficial for two adjacent micro-units 21 to form a "corner-to-corner" arrangement. The micro-units 21 have through holes 211 in the vertical direction to form a hollow structure, forming a high-loss antenna structure. Compared with the parallel conductive plate structure formed by the existing arrangement, the electric field is enhanced. A stronger electric field enhancement effect is achieved with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, thereby achieving a higher infrared absorption rate at high temperatures.

[0062] In some embodiments of the present invention, a plurality of micro-units 21 are arranged at intervals along the length and width directions of the functional layer 2, and the micro-unit array forms a two-dimensional triangular lattice. The two-dimensional triangular lattice is a lattice formed by periodically and closely arranged equilateral triangles. The minimum angle α between the side of the hexagon and the length direction of the functional layer 2 is -10° to 10°. For example, the minimum angle α between the side of the hexagon and the length direction of the functional layer 2 can be -10° to 9°, -6° to 6°, -5° to 5°, -2° to 2°, etc. Specifically, controlling the minimum angle between the side of the hexagon and the length direction of the functional layer 2 within the above range is beneficial for adjacent micro-units 21 to form a "corner-to-corner" arrangement. The micro-units 21 have through holes 211 in the vertical direction to form a hollow structure, forming a high-loss antenna structure. Compared with the parallel conductive plate structure formed by the existing arrangement, the electric field is enhanced. A stronger electric field enhancement effect is achieved with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, thereby achieving a higher infrared absorption rate at high temperatures.

[0063] In some embodiments of the present invention, any two micro-units 21 projected onto the protective layer 1 each have a first vertex, and the distance between the two first vertices is 3μm to 10μm. For example, the distance between the two first vertices can be 3μm to 9.9μm, 4μm to 9μm, 5μm to 8μm, 6μm to 7μm, etc. It can be understood that the first vertex refers to the point at the same position of each micro-unit 21. When all micro-units 21 are the same, the distance between the two first vertices can be called the period T (see [reference]). Figure 2This is equivalent to translating a micro-unit 21 along the length or width of the functional layer 2 to a distance coinciding with that of an adjacent micro-unit 21, controlling the distance between the two first vertices within the aforementioned range. This facilitates the formation of a "corner-to-corner" arrangement between adjacent micro-units 21. Furthermore, the micro-unit 21 has through-holes 211 running vertically to form a hollow structure, creating a high-loss antenna structure. Compared to the parallel conductive plate structure formed by existing arrangements, this structure enhances the electric field, achieving a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, resulting in higher infrared absorption at high temperatures. Simultaneously, the array contains multiple different high-loss antenna structures, allowing for absorption of infrared light at different wavelengths. Therefore, compared to existing technologies, this application achieves a higher infrared thermal emissivity over a wider wavelength range at high temperatures. Studies have shown that, within the wavelength range of 8μm to 13μm, the temperature-adaptive radiation-controlled film of this application exhibits a higher high-temperature thermal infrared emissivity by more than 30%, while a lower low-temperature thermal infrared emissivity by more than 30%. The modulation depth of the thermal infrared emissivity is significantly improved, which helps to substantially reduce the total annual energy consumption of the heating and cooling temperature control system.

[0064] The shape of the projection of the through hole 211 onto the protective layer 1 can be rectangular, circular, elliptical, triangular, or polygonal, and the present invention does not limit it.

[0065] In some embodiments of the present invention, the temperature-adaptive radiation temperature control film further includes a reflective layer 3 disposed below the functional layer 2. The reflective layer 3 has high reflectivity in the 0.4μm–0.76μm and 8μm–13μm (atmospheric window) wavelength bands. Specifically, the material of the reflective layer 3 includes at least one of aluminum, silver, gold, chromium, nickel, platinum, tin, and titanium. The temperature-adaptive radiation temperature control film containing the reflective layer 3 of the above materials is suitable for application to the surface of any object, such as buildings, vehicles, clothing, spacecraft, etc., and can stabilize the temperature of buildings, vehicles, clothing, spacecraft, etc. with zero power consumption, reducing the operating energy consumption of the temperature control system.

[0066] At low temperatures, W x V 1-x O2 (W represents the doping elements listed above) is in an infrared-transparent semiconductor phase. In this state, the temperature-adaptive radiation-controlled thin film approximates the mirror surface formed by reflective layer 3, exhibiting very low infrared absorptivity. According to Kirchhoff's law of infrared radiation, the temperature-adaptive radiation-controlled thin film in this state has very low thermal infrared emissivity. When the temperature of the temperature-adaptive radiation-controlled thin film is higher than W... x V 1-x At the phase transition temperature of O2, W x V 1-xO2 is in a highly dissipative metallic phase, leading to W x V 1-x There is a strong impedance mismatch between O2 and protective layer 1, and with the adjacent W x V 1-x The O2 element forms a high-dissipation optical antenna. When incident infrared light comes into contact with W... x V 1-x When using an O2 array, it will be in W x V 1-x The sidewalls of the O2 unit form evanescent waves, resulting in strong infrared absorption. According to Kirchhoff's theorem for infrared radiation, the temperature-adaptive radiation-controlled film in this state has a very high thermal infrared emissivity.

[0067] In other embodiments of the present invention, the temperature-adaptive radiation temperature control film further includes a reflective layer 3 disposed below the functional layer 2. The reflective layer 3 is made of at least one of indium tin oxide, aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal mesh, conductive polymers, and low-emissivity glass. This reflective layer 3 is an infrared reflective layer with high transmittance in the 0.4μm to 0.76μm band and high reflectance in the 8μm to 13μm band. The temperature-adaptive radiation temperature control film containing the reflective layer 3 of the above materials is suitable for application on the windows of buildings or vehicles, playing a passive radiation temperature control role. It has advantages such as low cost, mass production capability, thermal infrared emissivity that varies with temperature, adjustable temperature for cooling-heating mode switching, and high visible light transmittance. It can stabilize the temperature of buildings and vehicles with zero power consumption and reduce the operating energy consumption of the temperature control system.

[0068] In some embodiments of the present invention, the low-emissivity glass meets the national standard "Coated Glass Part 2: Low-emissivity Coated Glass" (GB / T 18915.2).

[0069] It is understood that when the temperature-adaptive radiation temperature control film of this application is applied to a glass substitute (such as low-emissivity glass) of a film system product composed of indium tin oxide (i.e., ITO film), aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal mesh, conductive polymer, or a film system product with multiple layers of metal or other compounds (such as ITO film) coated on the surface, the temperature-adaptive radiation temperature control film may not have a reflective layer 3. When it is functioning, indium tin oxide, aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal mesh, conductive polymer, and low-emissivity glass can act as reflective layer 3, which can further reduce costs.

[0070] In some embodiments of the present invention, the protective layer 1 has high transmittance in the 8μm to 13μm wavelength band. Infrared light in the 8μm to 13μm band is not absorbed, and the cooling body mainly uses infrared light in the 8μm to 13μm wavelength band. Specifically, the material of the protective layer 1 includes a transparent material, which includes at least one of polyethylene, colored polyethylene, EPDM rubber, polytetrafluoroethylene, polymethylpentene, MXene, hafnium oxide, magnesium fluoride, barium fluoride, and calcium fluoride. The aforementioned protective layer 1 allows infrared light in the 8μm–13μm wavelength band to enter the functional layer 2, facilitating a "corner-to-corner" arrangement of adjacent micro-units 21. Furthermore, the micro-units 21 have through-holes 211 running vertically to form a hollow structure, creating a high-loss antenna structure. Compared to the parallel conductive plate structure formed by existing arrangements, this enhances the electric field, achieving a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field leads to a higher electric field loss rate, resulting in higher infrared absorption at high temperatures. Simultaneously, the array contains multiple different high-loss antenna structures, allowing for absorption of infrared light of different wavelengths. Therefore, compared to existing technologies, this application achieves high thermal infrared emissivity over a wider wavelength range at high temperatures. Research shows that within the 8μm–13μm wavelength range, the high-temperature thermal infrared emissivity of the temperature-adaptive radiation-controlled film of this application is increased by more than 30%, while the low-temperature thermal infrared emissivity is reduced by more than 30%, contributing to a significant reduction in the annual total energy consumption of the heating and cooling temperature control system.

[0071] In some embodiments of the present invention, the material of the protective layer 1 further includes infrared transparent pigments, which include at least one of Prussian blue, zinc oxide, zinc selenide, zinc sulfide, barium fluoride, magnesium fluoride, calcium fluoride, ferric oxide, chromium oxide, silicon, and germanium. Using infrared transparent pigments of different colors in the protective layer 1 can, on the one hand, meet users' needs for film color and pattern. Products include roofs, glass, car covers, car windows, etc., in different colors. Secondly, when laying temperature-adaptive radiation-controlled films on the exterior surfaces of buildings in different cities / climate zones, the annual energy consumption of the heating and cooling system is related to the solar absorptivity of the film: there exists an optimal solar absorptivity that minimizes the annual energy consumption of the heating and cooling system, i.e., maximizes the total energy savings. Therefore, by optimizing the color and its depth, it can be ensured that films used in different cities can bring the best total annual energy savings. Taking a house in Seattle, USA, as an example, compared with traditional radiative cooling materials (solar absorptivity 0.05, thermal infrared emissivity 0.95), the relationship between the annual additional energy savings of the temperature-adaptive radiation-controlled film and the solar absorptivity is as follows: Figure 4As shown, by using infrared transparent pigments to optimize solar light absorption, the goal of maximizing total annual energy savings can be effectively achieved. Furthermore, the additional annual energy savings of this invention are significantly better than those of Comparative Example 1.

[0072] It is understood that the transparent material can be one or more layers. When the material of the protective layer 1 includes infrared transparent pigment, the infrared transparent pigment and the transparent material are mixed and placed in the same layer. It can also be divided into two or more layers. When divided into two layers, the positions of the two are not limited.

[0073] In some embodiments of the present invention, the protective layer 1 includes a first protective layer 1 disposed on the upper side of the functional layer 2 and a second protective layer 1 disposed on the upper side of the first protective layer 1. One of the first protective layer 1 and the second protective layer 1 includes the transparent material, and the other includes the infrared transparent pigment. When the temperature of the temperature-adaptive radiation-controlled film changes, vanadium dioxide or vanadium dioxide doped with one or more elements selected from chromium, tungsten, gallium, aluminum, iron, titanium, niobium, molybdenum, rhenium, fluorine, and hydrogen undergoes a phase transition, thereby changing the thermal infrared emissivity of the temperature-adaptive radiation-controlled film and thus achieving a cooling-warming mode switching. By adding one or more of the infrared transparent materials to the protective layer 1, the color and solar absorption rate of the temperature-adaptive radiation-controlled film can be changed. The color and solar absorption rate of the temperature-adaptive radiation-controlled film can be adjusted by changing the type, ratio, and coverage / concentration of the infrared transparent material.

[0074] See Figure 5 The protective layer consists of a multi-layered structure: protective layer a 11, protective layer b 12, and protective layer c 13. It exhibits high transmittance in the 8μm–13μm wavelength range. Protective layers a 11 and c 13 are composed of at least one of the following materials: polyethylene, colored polyethylene, EPDM rubber, polytetrafluoroethylene, polymethylpentene, MXene, hafnium oxide, magnesium fluoride, barium fluoride, and calcium fluoride. One or more layers of infrared-transparent pigment (protective layer b 12) are added between protective layers a 11 and c 13. The functional layer is composed of unit structures arranged in an array on the thin film. Each unit structure is a hollow rectangular pattern, and its main material is vanadium dioxide or vanadium dioxide doped with at least one of the following: chromium, tungsten, gallium, aluminum, iron, titanium, niobium, molybdenum, rhenium, fluorine, and hydrogen. The reflective layer exhibits high reflectivity in the 8μm–13μm wavelength range. The functional layer is embedded inside the protective layer, close to the reflective layer.

[0075] A second aspect of the present invention provides a method for preparing the temperature-adaptive radiation-controlled thin film described in the first aspect, comprising:

[0076] S100: Prepare a functional layer, the functional layer comprising a plurality of micro-units arranged in an array, each micro-unit having a polygonal projection on the protective layer, the micro-unit having a through hole extending vertically, the minimum distance between the vertices of the two polygons formed by two adjacent micro-units being d1, the distance between the midpoints of the sides of the two polygons formed by two adjacent micro-units being d2, d1 < d2, and the material of the micro-units including vanadium dioxide.

[0077] In some embodiments of the present invention, the functional layer can be prepared by the following methods:

[0078] Vanadium dioxide nanoparticles with a diameter of 0.01 μm to 1 μm were filled into the surface of the protective layer. The surface of the protective layer contained an array of micro-unit pits. Subsequently, excess vanadium dioxide powder was wiped off the surface of the protective layer, leaving only the vanadium dioxide powder filling the pits. Thus, the vanadium dioxide powder formed the desired functional layer.

[0079] S200: In some embodiments of the present invention, the protective layer described in S100 can be prepared by the following method:

[0080] The protective layer material is a thin film with a thickness of 5–100 μm, and its composition includes at least one of polyethylene, colored polyethylene, EPDM rubber, polytetrafluoroethylene, polymethylpentene, MXene, hafnium oxide, magnesium fluoride, barium fluoride, and calcium fluoride. The film, heated to 80°C–200°C, is aligned with a micro-unit array relief plate, and the pattern on the micro-unit array relief plate is imprinted onto the surface of the film at a speed of 0.1 cm / s–10 cm / s using a roll-to-roll imprinting device. Thus, the film with micro-unit array pits on its surface forms the desired protective layer.

[0081] Therefore, the temperature-adaptive radiation-controlled film prepared by this invention can achieve a greater infrared thermal emissivity modulation depth over a wider wavelength range, loses 30% less energy at low temperatures and releases 30% more energy at high temperatures than existing technologies; the solar absorption rate is reduced by about 50%, making it more suitable for use as a transparent coating that can be applied to glass surfaces; and the amount of vanadium dioxide used is reduced by about 50%, which is more conducive to cost savings.

[0082] In some embodiments of the present invention, after step S200, the method further includes:

[0083] S201: Fabrication of the reflective layer;

[0084] In some embodiments of the present invention, the reflective layer can be prepared by the following method:

[0085] The aforementioned composite film containing a vanadium dioxide micro-unit array, comprising a protective layer and a functional layer, is stacked on the surface of the reflective layer film, ensuring that the contact surface with the reflective layer film is the vanadium dioxide array side. The reflective layer film is made of at least one of the following materials: aluminum, silver, gold, chromium, nickel, platinum, tin, titanium, indium tin oxide, aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal meshes, conductive polymers, and low-emissivity glass. At a temperature of 80°C to 200°C and a speed of 0.1 cm / s to 10 cm / s, the stacked films are passed through a roll-to-roll laminating device, bonding the vanadium dioxide array-containing side of the composite film to the aluminum film. The resulting structure is... Figure 1 The three-layer structure shown.

[0086] In other embodiments of the present invention, the reflective layer can be prepared by the following method:

[0087] The aforementioned composite thin film containing a vanadium dioxide micro-unit array of protective and functional layers is placed in a vacuum sputtering deposition machine. Under an argon atmosphere and a power of 50W–1000W, a reflective layer film of 0.05μm–1μm is deposited on the surface of the composite thin film containing the vanadium dioxide array. The reflective layer film is made of at least one of the following materials: aluminum, silver, gold, chromium, nickel, platinum, tin, titanium, indium tin oxide, aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal meshes, and conductive polymers.

[0088] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0089] Example 1

[0090] 1. Protective layer material: polyethylene;

[0091] Protective layer preparation: The protective layer material is a polyethylene film with a thickness of 80 μm. The polyethylene film, heated to 125°C, is aligned with a micro-unit array relief plate and pressed onto the surface of the polyethylene film using a roll-to-roll imprinting device at a speed of 5 cm / s. This creates the desired protective layer on the polyethylene film with micro-unit array pits on its surface.

[0092] 2. Functional layer material: Vanadium dioxide;

[0093] Functional layer preparation: Vanadium dioxide nanoparticles with a diameter of less than 0.2 μm were filled into the surface of the protective layer. The surface of the protective layer has an array of micro-unit pits. Subsequently, excess vanadium dioxide powder was wiped off the surface of the protective layer, leaving only the vanadium dioxide powder filling the pits. Thus, the vanadium dioxide powder formed the desired functional layer.

[0094] The top view of the functional layer is as follows: Figure 2 As shown, the projection of the micro-unit on the protective layer is a square with a side length of 3.5 μm, a through-hole diameter of 2.5 μm, a thickness of 1.5 μm for each micro-unit, an angle of 45° between any side of the square and the length direction of the functional layer, and a period of 6 μm (distance between the two first vertices) for the micro-unit array structure.

[0095] Example 2

[0096] 1. Protective layer material: polyethylene;

[0097] Protective layer preparation: The protective layer material is a polyethylene film with a thickness of 80 μm. The polyethylene film, heated to 125°C, is aligned with a micro-unit array relief plate and pressed onto the surface of the polyethylene film using a roll-to-roll imprinting device at a speed of 5 cm / s. This creates the desired protective layer on the polyethylene film with micro-unit array pits on its surface.

[0098] 2. Functional layer material: Vanadium dioxide;

[0099] Functional layer preparation: Vanadium dioxide nanoparticles with a diameter of less than 0.2 μm were filled into the surface of the protective layer. The surface of the protective layer has an array of micro-unit pits. Subsequently, excess vanadium dioxide powder was wiped off the surface of the protective layer, leaving only the vanadium dioxide powder filling the pits. Thus, the vanadium dioxide powder formed the desired functional layer.

[0100] The top view of the functional layer is as follows: Figure 2 As shown, the projection of the micro-unit on the protective layer is a square with a side length of 3.5 μm, a through-hole diameter of 2.5 μm, a thickness of 1.5 μm for each micro-unit, an angle of 45° between any side of the square and the length direction of the functional layer, and a period of 6 μm (distance between the two first vertices) for the micro-unit array structure.

[0101] 3. Reflective layer material: Aluminum;

[0102] Reflective layer addition: The aforementioned functional layer and protective layer are stacked on the surface of the aluminum film, ensuring that the contact surface with the aluminum film is the functional layer side. At a temperature of 115°C and a speed of 3 cm / s, the laminated film is passed through a roll-to-roll laminating machine to bond the side of the composite film containing the vanadium dioxide array to the aluminum film.

[0103] Example 3

[0104] 1. Protective layer material: polyethylene;

[0105] Protective layer preparation: The protective layer material is a polyethylene film with a thickness of 80 μm. The polyethylene film, heated to 125°C, is aligned with a micro-unit array relief plate and pressed onto the surface of the polyethylene film using a roll-to-roll imprinting device at a speed of 5 cm / s. This creates the desired protective layer on the polyethylene film with micro-unit array pits on its surface.

[0106] 2. Functional layer material: Vanadium dioxide;

[0107] Functional layer preparation: Vanadium dioxide nanoparticles with a diameter of less than 0.2 μm were filled into the surface of the protective layer. The surface of the protective layer has an array of micro-unit pits. Subsequently, excess vanadium dioxide powder was wiped off the surface of the protective layer, leaving only the vanadium dioxide powder filling the pits. Thus, the vanadium dioxide powder formed the desired functional layer.

[0108] The top view of the functional layer is as follows: Figure 6 As shown, the projection of the micro-unit on the protective layer is an equilateral triangle with a side length of 5μm, a through-hole diameter of 2μm, a thickness of 1.5μm for each micro-unit, and a period of 5.5μm (distance between two first vertices) for the micro-unit array structure.

[0109] 3. Reflective layer material: Aluminum;

[0110] Reflective layer addition: The aforementioned functional layer and protective layer are stacked on the surface of the aluminum film, ensuring that the contact surface with the aluminum film is the functional layer side. At a temperature of 115°C and a speed of 3 cm / s, the laminated film is passed through a roll-to-roll laminating machine to bond the side of the composite film containing the vanadium dioxide array to the aluminum film.

[0111] Example 4

[0112] 1. Protective layer material: polyethylene;

[0113] Protective layer preparation: The protective layer material is a polyethylene film with a thickness of 80 μm. The polyethylene film, heated to 125°C, is aligned with a micro-unit array relief plate and pressed onto the surface of the polyethylene film using a roll-to-roll imprinting device at a speed of 5 cm / s. This creates the desired protective layer on the polyethylene film with micro-unit array pits on its surface.

[0114] 2. Functional layer material: Vanadium dioxide;

[0115] Functional layer preparation: Vanadium dioxide nanoparticles with a diameter of less than 0.2 μm were filled into the surface of the protective layer. The surface of the protective layer has an array of micro-unit pits. Subsequently, excess vanadium dioxide powder was wiped off the surface of the protective layer, leaving only the vanadium dioxide powder filling the pits. Thus, the vanadium dioxide powder formed the desired functional layer.

[0116] The top view of the functional layer is as follows: Figure 7 As shown, the projection of the micro-unit on the protective layer is a regular hexagon with a side length of 2.5 μm, a through-hole diameter of 3 μm, a thickness of 1.5 μm for each micro-unit, and a period of 5.5 μm (distance between two first vertices) for the micro-unit array structure.

[0117] 3. Reflective layer material: Aluminum;

[0118] Reflective layer addition: The aforementioned functional layer and protective layer are stacked on the surface of the aluminum film, ensuring that the contact surface with the aluminum film is the functional layer side. At a temperature of 115°C and a speed of 3 cm / s, the laminated film is passed through a roll-to-roll laminating machine to bond the side of the composite film containing the vanadium dioxide array to the aluminum film.

[0119] Examples 5-14 are identical to Example 2 in preparation steps and methods, except for the parameters (see Table 1). The structure of Example 13 is as follows: Figure 1 As shown, polyethylene and Prussian blue are in one layer, and the structure of Example 14 is as follows. Figure 5 As shown, 11 and 13 are polyethylene layers, and 12 is an iron oxide layer.

[0120] Comparative Example 1

[0121] 1. Protective layer material: polyethylene;

[0122] Protective layer preparation: The protective layer material is a 12μm thick polyethylene film. The polyethylene film, heated to 110℃, is aligned with a micro-unit array relief plate and pressed onto the surface of the polyethylene film using a roll-to-roll imprinting device at a speed of 0.2cm / s. This creates the desired protective layer on the polyethylene film with micro-unit array pits on its surface.

[0123] 2. Functional layer material: Vanadium dioxide;

[0124] Functional layer preparation: Vanadium dioxide nanoparticles with a diameter of 0.3 μm were filled into the surface of the protective layer. The surface of the protective layer has an array of micro-unit pits. Subsequently, excess vanadium dioxide powder was wiped off the surface of the protective layer, leaving only the vanadium dioxide powder filling the pits. Thus, the vanadium dioxide powder formed the desired functional layer.

[0125] The top view of the functional layer is as follows: Figure 3As shown, the projection of the micro-unit on the protective layer is a square without through holes. The side length of the square is 3μm, the thickness of each micro-unit is 1.5μm, the angle between any side of the square and the length direction of the functional layer is 0° or 90°, and the period of the micro-unit array structure is 5μm (distance between the two first vertices).

[0126] 3. Reflective layer material: Aluminum;

[0127] Reflective layer installation: The aforementioned functional layer and protective layer are stacked on the surface of the aluminum film, ensuring that the contact surface with the aluminum film is the functional layer side. At a temperature of 110°C and a speed of 0.2 cm / s, the laminated film is passed through a roll-to-roll laminating machine to bond the side of the composite film containing the vanadium dioxide array to the aluminum film.

[0128] Table 1

[0129]

[0130] The temperature-adaptive radiation-controlled film obtained in Example 1 was attached to low-emissivity glass. Electromagnetic analysis of Examples 1, 2, 3, 4, and Comparative Example 1 was performed using the finite element method, yielding the following results: Figures 8 to 15 .

[0131] Figure 8 The thermal infrared emissivity spectra of Comparative Example 1 and the temperature-adaptive radiation-controlled film of Example 1, applied to low-emissivity glass, at different temperatures reveal that in the infrared wavelength range of 8 μm to 13 μm, the modulation depth of the thermal infrared emissivity of Example 1 is higher than that of Comparative Example 1, reaching over 0.7. This demonstrates that this technology is comprehensively superior to Comparative Example 1 in cooling-warming applications in the infrared band.

[0132] Figure 9 The image shows a top view of the radiation loss rate distribution of the temperature-adaptive radiation-controlled thin films in Comparative Example 1 and Example 2 at a depth of 9 μm. Comparative Example 1 (left side) features a parallel conductive plate structure, achieving high absorption of the infrared band by the vanadium dioxide array at high temperatures. Example 2 features a high-loss antenna structure, achieving a stronger electric field enhancement effect with less vanadium dioxide. The enhanced electric field results in a higher electric field loss rate, thus achieving a higher thermal infrared emissivity than Comparative Example 1 at high temperatures.

[0133] Figure 10The diagram shows the electric field loss rate distribution (top view) of the temperature-adaptive radiation-controlled film of Example 2 at 9 μm and 12 μm. It can be seen that the temperature-adaptive radiation-controlled film of Example 2 forms two high-loss antenna structures. Multiple different high-loss antenna structures coexist in the array, allowing for absorption of infrared light at different wavelengths. Therefore, compared to Comparative Example 1, it achieves a higher infrared light absorption rate over a wider wavelength range. At low temperatures, the infrared light absorption rate increases rapidly with the increase in vanadium dioxide usage. Since Example 2 saves approximately 50% of vanadium dioxide compared to Comparative Example 1, the infrared absorption rate decreases by more than 36%, thus achieving a lower thermal infrared emissivity at low temperatures.

[0134] Figure 11 The thermal infrared emissivity spectra of Example 2 and Comparative Example 1 at different temperatures show that, within the wavelength range of 8 μm to 13 μm, Example 2 exhibits a 30% increase in thermal infrared emissivity at high temperatures compared to Comparative Example 1, while its thermal infrared emissivity decreases by 36% at low temperatures. This demonstrates that the technology is comprehensively superior to Comparative Example 1 in cooling-warming applications in the infrared band.

[0135] Vanadium dioxide cannot transmit visible light at different temperatures. Since the projected area occupied by vanadium dioxide in the high-loss antenna structure of Example 2 is greatly reduced compared with that of Comparative Example 1, the absorption rate and reflectivity of visible light are reduced by about 50%, which greatly increases the transmittance of visible light. This makes it more suitable for combination with low-emissivity glass and / or indium tin oxide, zinc aluminum oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal meshes, and conductive polymer films to achieve a transparent temperature-adaptive radiation-controlled film.

[0136] Since the vanadium dioxide thickness required for the new structure in this application embodiment is no different from that in Comparative Example 1, the amount of vanadium dioxide required is reduced by about 50%, which greatly reduces the production cost and makes it more suitable for large-scale production.

[0137] Figure 12 The diagram shows the electric field loss rate distribution (top view) of the temperature-adaptive radiation-controlled film of Example 3 at 9 μm and 12 μm. It can be seen that the temperature-adaptive radiation-controlled film of Example 3 forms two high-loss antenna structures. Multiple different high-loss antenna structures coexist in the array, allowing for absorption of infrared light at different wavelengths. Therefore, compared to Comparative Example 1, Example 3 achieves a higher infrared light absorption rate over a wider wavelength range. At low temperatures, the infrared absorption rate increases rapidly with the increase of vanadium dioxide usage. Since the triangular version of Example 3 saves approximately 40% of vanadium dioxide compared to Comparative Example 1, the infrared absorption rate decreases by approximately 30%, thus achieving a lower thermal infrared emissivity at low temperatures.

[0138] Figure 13 The thermal infrared emissivity spectra of Example 3 and Comparative Example 1 at different temperatures are shown. Compared with Comparative Example 1, it can be found that Example 3 has an increased thermal infrared emissivity of approximately 33% at high temperatures in the infrared wavelength range of 8μm to 13μm, while its thermal infrared emissivity is reduced by 30% at low temperatures. This proves that Example 3 is superior to Comparative Example 1 in terms of cooling-warming applications in the infrared band.

[0139] Vanadium dioxide cannot transmit visible light at different temperatures. Since the projected area occupied by vanadium dioxide in the high-loss antenna structure of Example 3 is greatly reduced compared with that of Comparative Example 1, the absorption rate and reflectivity of visible light are reduced by about 40%, which greatly increases the transmittance of visible light. This makes it more suitable for combination with low-emissivity glass and / or indium tin oxide, aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal meshes, and conductive polymer films to achieve a transparent temperature-adaptive radiation-controlled film.

[0140] Since the required vanadium dioxide thickness in Example 3 is no different from that in Comparative Example 1, the amount of vanadium dioxide required is reduced by about 40%, which greatly reduces the production cost of Example 3 and makes it more suitable for large-scale production.

[0141] Figure 14 The diagram shows the electric field loss rate distribution of the temperature-adaptive radiation-controlled film in Example 4 at 9 μm and 12 μm (top view). It can be seen that the temperature-adaptive radiation-controlled film in Example 4 forms two high-loss antenna structures. Multiple different high-loss antenna structures exist simultaneously in the array, which can absorb infrared light of different wavelengths. Therefore, compared with Comparative Example 1, Example 4 can achieve a high infrared light absorption rate in a wider wavelength range.

[0142] Figure 15 The thermal infrared emissivity spectra of Example 4 and Comparative Example 1 at different temperatures are shown. Compared with Comparative Example 1, it can be found that in the infrared wavelength range of 8μm to 13μm, the thermal infrared emissivity at high temperatures is increased by about 32%, while the thermal infrared emissivity at low temperatures is decreased by 36%. This proves that the technology is superior to Comparative Example 1 in all aspects of cooling-warming applications in the infrared band.

[0143] Vanadium dioxide cannot transmit visible light at different temperatures. Since the projected area occupied by vanadium dioxide in the high-loss antenna structure of Example 4 is greatly reduced compared with that of Comparative Example 1, the absorption rate and reflectivity of visible light are reduced by about 56%, which greatly increases the transmittance of visible light. This makes it more suitable for combination with low-emissivity glass and / or indium tin oxide, zinc aluminum oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal meshes, and conductive polymer films to achieve a transparent temperature-adaptive radiation-controlled film.

[0144] Since the required vanadium dioxide thickness in Example 4 is no different from that in Comparative Example 1, the amount of vanadium dioxide required is reduced by about 56%, which greatly reduces the production cost of Example 4 and makes it more suitable for large-scale production.

[0145] In summary, the temperature-adaptive radiation-controlled film of this invention can achieve the use of less vanadium dioxide and various high-loss antenna structures, thereby enabling absorption of infrared light of different wavelengths. It can achieve a greater modulation depth of infrared thermal emissivity over a wider wavelength range, reducing energy loss by more than 30% at low temperatures and releasing more than 30% more energy at high temperatures compared to existing technologies. The thermal infrared emissivity can change with temperature, and the modulation depth of thermal infrared emissivity is large. The visible light absorption and reflectivity of the vanadium dioxide array are reduced by about 50%, making it more suitable for use as a transparent coating that can be applied to glass surfaces. Furthermore, the amount of vanadium dioxide used is reduced by about 50%, which is more conducive to cost savings.

[0146] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0147] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A temperature-adaptive radiation-controlled thin film, characterized in that, It includes a functional layer and a protective layer disposed on the upper side of the functional layer, wherein: The functional layer includes multiple micro-units arranged in an array. The projection of each micro-unit on the protective layer is a polygon. The micro-unit has a through hole in the vertical direction. The minimum distance between the vertices of the two polygons formed by two adjacent micro-units is d1, and the distance between the midpoints of the sides of the two polygons formed by two adjacent micro-units is d2, where d1 < d2. The material of the micro-unit includes vanadium dioxide.

2. The temperature-adaptive radiation-controlled thin film according to claim 1, characterized in that, The vanadium dioxide contains a doping element, which includes at least one of chromium, tungsten, gallium, aluminum, iron, titanium, niobium, molybdenum, rhenium, fluorine, and hydrogen.

3. The temperature-adaptive radiation-controlled thin film according to claim 2, characterized in that, The number of atoms of the doping element accounts for 0 to 10% of the number of vanadium atoms in vanadium dioxide.

4. The temperature-adaptive radiation-controlled thin film according to any one of claims 1 to 3, characterized in that, The projection of the micro-unit onto the protective layer is a triangle, quadrilateral, or hexagon; and / or, The thickness of each micro-unit is 0.1 μm to 3 μm.

5. The temperature-adaptive radiation-controlled thin film according to any one of claims 1 to 3, characterized in that, The projection of the micro-unit onto the protective layer is a triangle, quadrilateral, or hexagon, and the side length of the triangle, quadrilateral, or hexagon is 1μm to 6μm. Optionally, a plurality of the micro-units are arranged at intervals along the length and width directions of the functional layer, and the angle between any side of the quadrilateral and the length direction of the functional layer is 35° to 55°. Optionally, a plurality of the micro-units are arranged at intervals along the length and width directions of the functional layer, and the minimum angle between the sides of the triangle and the length direction of the functional layer is -10° to 10°. Optionally, a plurality of the micro-units are arranged at intervals along the length and width directions of the functional layer, and the minimum angle between the side of the hexagon and the length direction of the functional layer is -10° to 10°. Optionally, any two of the micro-units projected onto the protective layer each have a first vertex, and the distance between the two first vertices is 3μm to 10μm.

6. The temperature-adaptive radiation-controlled thin film according to any one of claims 1 to 3, characterized in that, The temperature-adaptive radiation-controlled film further includes a reflective layer disposed below the functional layer, wherein the reflective layer is made of at least one of aluminum, iron, copper, silver, gold, chromium, nickel, platinum, tin, and titanium; or, The temperature-adaptive radiation-controlled film further includes a reflective layer disposed below the functional layer. The reflective layer is made of at least one of indium tin oxide, aluminum zinc oxide, gallium-doped zinc oxide, graphene, carbon nanotubes, metal nanowires, metal mesh, conductive polymers, and low-emissivity glass.

7. The temperature-adaptive radiation-controlled thin film according to any one of claims 1 to 3, characterized in that, The protective layer is made of a permeable material, which includes at least one of polyethylene, colored polyethylene, EPDM rubber, polytetrafluoroethylene, polymethylpentene, MXene, hafnium oxide, magnesium fluoride, barium fluoride, and calcium fluoride.

8. The temperature-adaptive radiation-controlled thin film according to claim 7, characterized in that, The protective layer also includes infrared transparent pigments, which include at least one of Prussian blue, zinc oxide, zinc selenide, zinc sulfide, barium fluoride, magnesium fluoride, calcium fluoride, ferric oxide, chromium oxide, silicon, and germanium.

9. The temperature-adaptive radiation-controlled thin film according to claim 8, characterized in that, The protective layer includes a first protective layer disposed on the upper side of the functional layer and a second protective layer disposed on the upper side of the first protective layer. One of the first protective layer and the second protective layer includes the transparent material, and the other includes the infrared transparent pigment.

10. A method for preparing a temperature-adaptive radiation-controlled thin film according to any one of claims 1 to 9, characterized in that, include: A functional layer is prepared, the functional layer comprising a plurality of micro-units arranged in an array, each micro-unit having a polygonal projection on the protective layer, the micro-unit having a through hole extending vertically, the minimum distance between the vertices of the two polygons formed by two adjacent micro-units being d1, the distance between the midpoints of the sides of the two polygons formed by two adjacent micro-units being d2, d1 < d2, and the material of the micro-units including vanadium dioxide. A protective layer is prepared on the upper side of the functional layer to obtain a temperature-adaptive radiation-controlled film.

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