A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, its preparation method and application

Abstract

This invention relates to a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, its preparation method, and its application. It belongs to the field of energy-saving and emission-reduction intelligent materials and infrared camouflage materials. This invention aims to solve the problem that existing VO2 coatings can only achieve amplitude regulation in radiative cooling or only in thermal camouflage. The dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance is prepared from rod-shaped VO2 micro / nano powder, solvent, dispersant, defoamer, binder, thickener, and leveling agent. The preparation method includes: 1. Preparation of rod-shaped VO2 micro / nano powder; 2. Preparation of VO2 coating. Applications: When coated on a high-reflectivity substrate, it achieves heat-driven adaptive thermal control; when coated on a high-emissivity substrate, it achieves heat-driven adaptive thermal camouflage.

Description

Technical Field

[0001] This invention belongs to the field of energy-saving and emission-reduction smart materials and infrared camouflage materials preparation. Background Technology

[0002] With increasing global attention to climate change, zero-energy thermal management materials, such as radiative cooling, have garnered widespread interest. However, traditional radiative cooling materials primarily rely on their inherent properties for passive cooling, failing to meet the thermal management needs of changing environments and easily leading to overcooling or overheating, resulting in additional energy consumption. Simultaneously, with the rapid development of modern warfare reconnaissance technologies and precision-guided weapons, infrared thermal imaging technology is increasingly widely used, becoming a crucial tool for battlefield reconnaissance and guided weapons, placing higher demands on stealth technologies that conceal the infrared radiation characteristics of targets. Currently used static infrared camouflage loses its stealth effect when the environment changes due to inconsistencies between the stealth material and the background spectral signal. Dynamic temperature adaptive control materials, on the other hand, introduce the concepts of adaptability and intelligent control, dynamically adjusting their optical properties to respond to external changes. They can dynamically adjust their performance according to changes in external conditions or user needs, thereby achieving efficient and flexible thermal management and thermal camouflage performance in a wider range of scenarios.

[0003] While researchers have achieved dynamic tunability of radiation performance in recent years through responses to temperature, humidity, voltage, and mechanical force, utilizing the dynamic infrared emissivity of materials to respond to external stimuli and thus dynamically stabilize temperature in fluctuating thermal environments, most adaptive thermal control materials are fabricated on rigid substrates. These materials require specially designed optical structures, resulting in high costs, complex designs, and limited flexibility in substrate selection based on application environments. VO2, as a typical thermo-induced phase change material, exhibits a 3-4 order of magnitude abrupt change in conductivity before and after the phase change, and its emissivity shows a negative differential change. This makes it highly suitable for preparing coatings that, when paired with appropriate application substrates, achieve positive / negative differential emissivity performance. However, currently common VO2 coatings can only achieve temperature-adaptive thermal radiation control for a single performance characteristic, only achieving amplitude control in radiative cooling or only in thermal camouflage. Summary of the Invention

[0004] This invention aims to address the problem that existing VO2 coatings can only achieve amplitude regulation in terms of radiative cooling or only in terms of thermal camouflage, and provides a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, its preparation method, and its application.

[0005] A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance is prepared by mass fractions of 1 to 1000 parts rod-shaped VO2 micro / nano powder, 800 to 1000 parts solvent, 20 to 30 parts dispersant, 40 to 60 parts defoamer, 1000 to 1999 parts binder, 10 to 20 parts thickener and 10 to 20 parts leveling agent.

[0006] A method for preparing a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, comprising the following steps:

[0007] I. Preparation of rod-shaped VO2 micro / nano powder:

[0008] Vanadium pentoxide powder and oxalic acid dihydrate powder were added sequentially to deionized water and mixed thoroughly under magnetic stirring until the solution changed from yellow to green and finally to dark blue, resulting in a mixture. The mixture was then subjected to hydrothermal reaction at 220℃~240℃ for 1h~6h. After cooling to room temperature, the mixture was washed and centrifuged to obtain a dark black precipitate, i.e., VO2(B). The dark black precipitate was dried and then heat-treated at 500℃~550℃ for 30min~2h under an argon atmosphere to obtain rod-shaped VO2 micro / nano powder, i.e., VO2(M).

[0009] The mass ratio of vanadium pentoxide powder to oxalic acid dihydrate powder is 1:(1.25-1.6); the mass ratio of vanadium pentoxide powder to deionized water is 1g:(40-50)mL.

[0010] II. Preparation of VO2 coatings:

[0011] Weigh out 1 to 1000 parts by weight of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, 40 to 60 parts of defoamer, 1000 to 1999 parts of binder, 10 to 20 parts of thickener, and 10 to 20 parts of leveling agent. Mix 1 to 1000 parts of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, and 40 to 60 parts of defoamer evenly, and then pre-disperse to obtain a pre-dispersed slurry. Then add 1000 to 1999 parts of binder, 10 to 20 parts of thickener, and 10 to 20 parts of leveling agent to the pre-dispersed slurry for dispersion to obtain a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance.

[0012] An application of a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance is disclosed. It is applied to a high-reflectivity substrate and a high-emissivity substrate. When applied to a high-reflectivity substrate, it achieves thermally driven adaptive thermal control. When applied to a high-emissivity substrate, it achieves thermally driven adaptive thermal camouflage.

[0013] The beneficial effects of this invention are:

[0014] This invention selects a VO2 rod-shaped structure as the functional phase, which can play a role in dynamic thermal management and thermal camouflage. Compared with the commonly used spherical and linear structures, the rod-shaped structure is an intermediate state, which can realize the functions of both states. Therefore, by adjusting the distribution of the functional phase in the coating, the overlapping structure of the functional phase in the coating can be controlled, and the switching between positive differential emissivity performance and negative differential emissivity performance can be achieved.

[0015] At low temperatures, VO2(M) is in an insulating state, and the functional layer is in a state of high infrared transmittance; the overall effect is dominated by the substrate. At high temperatures, VO2 transforms into the R phase. High-content VO2 rod-shaped particles overlap each other, transforming into a metallic phase with high reflectivity and reduced emissivity, meeting the requirements for infrared camouflage. Low-content VO2 rod-shaped particles form adjacent antennas, utilizing the inter-regional photon resonance phenomenon to increase emissivity, meeting the requirements for intelligent thermal control.

[0016] Therefore, this invention utilizes the abrupt change in conductivity of VO2 powder before and after phase transition, and mixes it with an appropriate amount of infrared transparent solvent and binder to prepare a heat-driven adaptive thermal radiation control coating. Based on the substrate on which the coating is applied and the change in the content of functional particles in the coating, a heat-driven adaptive thermal control coating with reversible emissivity change with ambient temperature on a high reflectivity substrate can be obtained, exhibiting a positive differential emissivity change; or a heat-driven adaptive thermal camouflage coating with reversible emissivity change with ambient temperature on a high emissivity substrate can be obtained, exhibiting a negative differential emissivity change.

[0017] Therefore, this invention can achieve dynamic thermal management to maintain the temperature requirements of combat personnel and reduce the probability of detection by the enemy in terms of infrared camouflage by simply adjusting the concentration of the coating, thereby significantly improving the safety of combat personnel. The temperature-adaptive thermal radiation control coating involved in this invention has relaxed preparation conditions, is easy to mass-produce, has low production costs and low application environment requirements, and is suitable for dynamically controlling infrared radiation characteristics according to environmental requirements, improving the material's autonomous thermal control capability, and achieving energy-saving / camouflage effects.

[0018] This invention relates to a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, its preparation method, and its application. Attached Figure Description

[0019] Figure 1 The images are TEM images of the rod-shaped VO2 micro / nano powder prepared in step one of Example 1: (a) low-resolution image, (b) high-resolution image, and (c) SAED pattern.

[0020] Figure 2This is a SEM image of the rod-shaped VO2 micro / nano powder prepared in step one of Example 1. Detailed Implementation

[0021] Specific Implementation Method 1: This implementation method describes a dynamic thermal management coating with temperature adaptive thermal radiation regulation performance, which is prepared by mass fractions of 1 to 1000 parts of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, 40 to 60 parts of defoamer, 1000 to 1999 parts of binder, 10 to 20 parts of thickener and 10 to 20 parts of leveling agent.

[0022] The beneficial effects of this embodiment are:

[0023] This embodiment selects a VO2 rod-shaped structure as the functional phase, which can play a role in dynamic thermal management and thermal camouflage. Compared with the commonly used spherical and linear structures, the rod-shaped structure is an intermediate state, which can realize the functions of both states. Therefore, by adjusting the distribution of the functional phase in the coating, the overlapping structure of the functional phase in the coating can be controlled, and the switching between positive differential emissivity performance and negative differential emissivity performance can be realized.

[0024] At low temperatures, VO2(M) is in an insulating state, and the functional layer is in a state of high infrared transmittance; the overall effect is dominated by the substrate. At high temperatures, VO2 transforms into the R phase. High-content VO2 rod-shaped particles overlap each other, transforming into a metallic phase with high reflectivity and reduced emissivity, meeting the requirements for infrared camouflage. Low-content VO2 rod-shaped particles form adjacent antennas, utilizing the inter-regional photon resonance phenomenon to increase emissivity, meeting the requirements for intelligent thermal control.

[0025] Therefore, this embodiment utilizes the characteristic of the abrupt change in conductivity of VO2 powder before and after phase transition, and mixes it with an appropriate amount of infrared transparent solvent and binder to prepare a heat-driven adaptive thermal radiation control coating. Based on the substrate on which the coating is applied and the change in the content of functional particles in the coating, a heat-driven adaptive thermal control coating with reversible conversion of emissivity with ambient temperature on a high reflectivity substrate can be obtained, which exhibits a positive differential emissivity change; or a heat-driven adaptive thermal camouflage coating with reversible conversion of emissivity with ambient temperature on a high emissivity substrate can be obtained, which exhibits a negative differential emissivity change.

[0026] Therefore, this embodiment can achieve the maintenance of personnel's temperature requirements in dynamic thermal management and reduce the probability of detection by the enemy in terms of infrared camouflage by simply adjusting the coating concentration, thereby significantly improving the safety of personnel. The temperature-adaptive thermal radiation control coating involved in this embodiment has relaxed preparation conditions, is easy to mass-produce, has low production costs and low application environment requirements, and is suitable for dynamic control of infrared radiation characteristics according to environmental requirements, improving the material's autonomous thermal control capability and achieving energy-saving / camouflage effects.

[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the solvent used is water, xylene, alcohol solvents, ketone solvents, ester solvents, or dichloromethane. Everything else is the same as in Specific Implementation Method One.

[0028] In this specific embodiment, the solvent not only dissolves the film-forming substances in the coating and adjusts the viscosity of the coating, but also ensures that the VO2 powder is evenly dispersed, which is more conducive to the coating being evenly covered on the surface of the object.

[0029] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the adhesive is a solvent-based resin or a water-soluble resin; the solvent-based resin is Karton resin, polyamide resin, phenolic resin, or vinyl resin; the water-soluble resin is waterborne polyurethane, acrylic resin, or epoxy resin. Everything else is the same as in Specific Implementation Method One or Two.

[0030] In this specific embodiment, the binder exhibits infrared transparency in the coating, binding various substances in the coating together and adhering them to the coated surface. It also provides the coating with sufficient mechanical strength to resist abrasion, scratches, and other physical damage. Simultaneously, it imparts weather resistance and chemical resistance to the coating, extending its service life.

[0031] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the dispersant is a polystyrene-maleic anhydride copolymer, a general-purpose organosilicon dispersant, or a POP polyether dispersant; the defoamer is an organosilicon defoamer or a polyether-modified polysiloxane defoamer. Everything else is the same as in Specific Implementation Methods One to Three.

[0032] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the thickener is polyethylene oxide, polypropylene oxide, or hydroxyethyl cellulose; and the leveling agent is polyether-modified polysiloxane, polyacrylate, or alkyl or phenyl-modified polysiloxane. Everything else is the same as in Specific Implementation Methods One to Four.

[0033] Specific Implementation Method Six: This implementation method provides a method for preparing a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, which is carried out according to the following steps:

[0034] I. Preparation of rod-shaped VO2 micro / nano powder:

[0035] Vanadium pentoxide powder and oxalic acid dihydrate powder were added sequentially to deionized water and mixed thoroughly under magnetic stirring until the solution changed from yellow to green and finally to dark blue, resulting in a mixture. The mixture was then subjected to hydrothermal reaction at 220℃~240℃ for 1h~6h. After cooling to room temperature, the mixture was washed and centrifuged to obtain a dark black precipitate, i.e., VO2(B). The dark black precipitate was dried and then heat-treated at 500℃~550℃ for 30min~2h under an argon atmosphere to obtain rod-shaped VO2 micro / nano powder, i.e., VO2(M).

[0036] The mass ratio of vanadium pentoxide powder to oxalic acid dihydrate powder is 1:(1.25-1.6); the mass ratio of vanadium pentoxide powder to deionized water is 1g:(40-50)mL.

[0037] II. Preparation of VO2 coatings:

[0038] Weigh out 1 to 1000 parts by weight of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, 40 to 60 parts of defoamer, 1000 to 1999 parts of binder, 10 to 20 parts of thickener, and 10 to 20 parts of leveling agent. Mix 1 to 1000 parts of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, and 40 to 60 parts of defoamer evenly, and then pre-disperse to obtain a pre-dispersed slurry. Then add 1000 to 1999 parts of binder, 10 to 20 parts of thickener, and 10 to 20 parts of leveling agent to the pre-dispersed slurry for dispersion to obtain a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance.

[0039] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that: the washing and centrifugation in step one specifically involves washing twice with deionized water, followed by centrifugation at 6000 rpm to 8000 rpm for 8 to 10 minutes; the drying in step one specifically involves drying at 60°C to 80°C for 4 to 8 hours. Everything else is the same as in Specific Implementation Method Six.

[0040] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Six or Seven in that: the pre-dispersion described in step two is specifically carried out at a rotation speed of 600 rpm to 800 rpm for 30 to 40 minutes; the dispersion described in step two is specifically carried out at a rotation speed of 600 rpm to 800 rpm for 20 to 30 minutes. Everything else is the same as in Specific Implementation Method Six or Seven.

[0041] Specific Implementation Method Nine: This implementation method describes the application of a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, which is coated on a high-reflectivity substrate and a high-emissivity substrate; when coated on a high-reflectivity substrate, it achieves thermally driven adaptive thermal control; when coated on a high-emissivity substrate, it achieves thermally driven adaptive thermal camouflage.

[0042] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that: the coating is applied to a high-reflectivity substrate and a high-emissivity substrate with a coating thickness of 0.7mm to 1mm; the high-reflectivity substrate is Al, Au, Ag, Mg, Ni, Zn, or Cu; the high-emissivity substrate is SiC, Fe2O3, SiO2, or polyimide. Everything else is the same as in Specific Implementation Method Nine.

[0043] The beneficial effects of the present invention are verified using the following embodiments:

[0044] Example 1:

[0045] A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance is prepared by mass parts of 1 part rod-shaped VO2 micro-nano powder, 1000 parts solvent, 30 parts dispersant, 60 parts defoamer, 1999 parts binder, 20 parts thickener and 20 parts leveling agent.

[0046] The solvent is water.

[0047] The adhesive is water-based polyurethane, manufactured by Shanghai McLean Biochemical Technology Co., Ltd., and its model number is A909856.

[0048] The dispersant is polystyrene-maleic anhydride copolymer, Shanghai Maclean Biochemical Technology Co., Ltd., S909954;

[0049] The defoamer mentioned is Shanghai Boding Chemical's DOWSILACP-3073 defoamer complex;

[0050] The thickener is polyethylene oxide, Shanghai Aladdin Biochemical Technology Co., Ltd., P432440;

[0051] The leveling agent mentioned is Beijing Maier Chemical HY-5030.

[0052] The preparation method of the above-mentioned dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance is carried out according to the following steps:

[0053] I. Preparation of rod-shaped VO2 micro / nano powder:

[0054] 1.2 g of vanadium pentoxide powder (V2O5) and 1.6642 g of oxalic acid dihydrate powder (H2C2O4·2H2O) were added sequentially to 60 mL of deionized water and mixed thoroughly under magnetic stirring until the solution changed from yellow to green and finally to dark blue, resulting in a mixture. The mixture was then subjected to hydrothermal reaction at 240 °C for 3 h. After cooling to room temperature, it was washed twice with deionized water and then centrifuged at 6000 rpm for 8 min to obtain a dark black precipitate, i.e., VO2(B). The dark black precipitate was dried at 80 °C for 6 h and then heat-treated at 500 °C for 2 h under an argon atmosphere to obtain rod-shaped VO2 micro / nano powder, i.e., VO2(M).

[0055] II. Preparation of VO2 coatings:

[0056] Weigh out 1 part by weight of rod-shaped VO2 micro / nano powder, 1000 parts of solvent, 30 parts of dispersant, 60 parts of defoamer, 1999 parts of binder, 20 parts of thickener, and 20 parts of leveling agent. Mix the 1 part rod-shaped VO2 micro / nano powder, 1000 parts of solvent, 30 parts of dispersant, and 60 parts of defoamer evenly, and then pre-disperse at 600 rpm for 30 min to obtain a pre-dispersed slurry. Then add 1999 parts of binder, 20 parts of thickener, and 20 parts of leveling agent to the pre-dispersed slurry and disperse at 800 rpm for 20 min to obtain a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, namely VO2 coating.

[0057] The above-mentioned application of a dynamic thermal management coating with temperature adaptive thermal radiation regulation performance involves coating VO2 coating on a high reflectivity substrate with a coating thickness of 0.82 mm, leveling for 10 min after coating, and finally drying at 80℃ for 30 min to obtain a thermally driven adaptive thermal control device.

[0058] The high reflectivity substrate is Al.

[0059] The infrared radiation temperature of the thermally driven adaptive thermal controller was recorded in the 8-14μm wavelength range within the temperature range of 30℃ to 100℃, with the emissivity varying from 0.2 to 0.57.

[0060] Example 2: This example differs from Example 1 in that it presents a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance. It is prepared by weight of 2 parts rod-shaped VO2 micro / nano powder, 1000 parts solvent, 30 parts dispersant, 60 parts defoamer, 1990 parts binder, 20 parts thickener, and 20 parts leveling agent. The application of this dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance involves coating the VO2 coating onto a high-reflectivity substrate to a thickness of 0.80 mm. After coating, leveling is performed for 10 minutes, and finally, drying is carried out at 80°C for 30 minutes to obtain a heat-driven adaptive thermal control device. Everything else is the same as in Example 1.

[0061] The addition of functional phases improved the difference in emissivity. The infrared radiation temperature of the thermally driven adaptive thermal controller in the 8-14 μm wavelength range was recorded in the temperature range of 30℃ to 100℃, and the emissivity changed from 0.34 to 0.84.

[0062] Example 3: This example differs from Example 1 in that it presents a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance. It is prepared by weight of 20 parts rod-shaped VO2 micro / nano powder, 1000 parts solvent, 30 parts dispersant, 60 parts defoamer, 1950 parts binder, 20 parts thickener, and 20 parts leveling agent. The application of this dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance involves coating the VO2 coating onto a high-reflectivity substrate with a thickness of 0.83 mm. After coating, leveling is performed for 10 minutes, and finally, drying is carried out at 80°C for 30 minutes to obtain a heat-driven adaptive thermal control device. Everything else is the same as in Example 1.

[0063] The further increase in functional phases actually reduced the negative differential emissivity performance. The emissivity of the thermally driven adaptive thermal controller changed from 0.66 to 0.97 in the infrared radiation temperature range of 8-14 μm wavelength within the temperature range of 30℃ to 100℃.

[0064] Example 4: This example differs from Example 1 in that it presents a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance. It is prepared by mass fractions of 200 parts rod-shaped VO2 micro / nano powder, 1000 parts solvent, 26 parts dispersant, 60 parts defoamer, 1800 parts binder, 18 parts thickener, and 18 parts leveling agent. The application of this dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance involves coating the VO2 coating onto a high-emissivity substrate with a thickness of 0.81 mm. After coating, leveling is performed for 10 minutes, and finally, drying is carried out at 80°C for 30 minutes to obtain a thermally driven adaptive thermal camouflage device. The high-emissivity substrate is SiO2. Everything else is the same as in Example 1.

[0065] With further increases in functional phase content, the positive differential emissivity performance is transformed into negative differential emissivity performance. The infrared radiation temperature of the thermally driven adaptive thermal camouflage device in the 8-14 μm wavelength range within the temperature range of 30℃ to 100℃ was recorded, and the emissivity changed from 0.95 to 0.85.

[0066] Example 5: This example differs from Example 1 in that it presents a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance. It is prepared by weight of 500 parts rod-shaped VO2 micro / nano powder, 900 parts solvent, 20 parts dispersant, 50 parts defoamer, 1500 parts binder, 14 parts thickener, and 14 parts leveling agent. The application of this dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance involves coating the VO2 coating onto a high-emissivity substrate with a thickness of 0.85 mm. After coating, leveling is performed for 10 minutes, and finally, drying is carried out at 80°C for 30 minutes to obtain a thermally driven adaptive thermal camouflage device. The high-emissivity substrate is SiO2. Everything else is the same as in Example 1.

[0067] The infrared radiation temperature of the thermally driven adaptive thermal camouflage device was recorded in the 8-14 μm wavelength range within the temperature range of 30℃ to 100℃, with the emissivity varying from 0.98 to 0.81.

[0068] Example 6: This example differs from Example 1 in that it presents a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance. It is prepared by mass fractions of 1000 parts rod-shaped VO2 micro / nano powder, 800 parts solvent, 20 parts dispersant, 40 parts defoamer, 1000 parts binder, 10 parts thickener, and 10 parts leveling agent. The application of this dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance involves coating the VO2 coating onto a high-emissivity substrate with a thickness of 0.87 mm. After coating, leveling is performed for 10 minutes, and finally, drying is carried out at 80°C for 30 minutes to obtain a thermally driven adaptive thermal camouflage device. The high-emissivity substrate is SiO2. Everything else is the same as in Example 1.

[0069] The infrared radiation temperature of the thermally driven adaptive thermal camouflage device was recorded in the 8-14 μm wavelength range within the temperature range of 30℃ to 100℃, with the emissivity varying from 0.97 to 0.69.

[0070] Figure 1 TEM images of the rod-shaped VO2 micro / nano powder prepared in step one of Example 1 are shown: (a) low-resolution image, (b) high-resolution image, and (c) SAED pattern. As can be seen from the figures, the length of these nanorods ranges from 500 nm to 1200 nm, and the width ranges from 57 nm to 120 nm. Furthermore, distinct lattice planes are also observed. Figure 1b), with a plane spacing of d = 0.3221 nm, corresponds to the (011) plane of monoclinic VO2. The distinct lattice edges also indicate a high degree of crystallinity in the synthesized VO2. Based on the selected area electron diffraction (SAED) pattern ( Figure 1 c) The bright diffraction spots show that the (011), (202), (100) and (210) planes of the M phase VO2 have good crystallinity, thus confirming the polymorphism of VO2 nanorods.

[0071] Figure 2 This is a SEM image of the rod-shaped VO2 micro / nano powder prepared in step one of Example 1; (The image is from...) Figure 2 (a) It can be seen that the prepared VO2 exhibits a uniform and complete nanorod shape, which corresponds to the TEM results.

Claims

1. A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance, characterized in that... It is coated onto high-reflectivity and high-emissivity substrates; When it is prepared by mass fractions of 1 to 20 parts of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, 40 to 60 parts of defoamer, 1000 to 1999 parts of binder, 10 to 20 parts of thickener and 10 to 20 parts of leveling agent, and coated on a high-reflectivity substrate, thermally driven adaptive thermal control is achieved. When it is prepared by mass fractions of 200-1000 parts rod-shaped VO2 micro / nano powder, 800-1000 parts solvent, 20-30 parts dispersant, 40-60 parts defoamer, 1000-1999 parts binder, 10-20 parts thickener and 10-20 parts leveling agent, and coated on a high-emissivity substrate, it achieves thermally driven adaptive thermal camouflage. The rod-shaped VO2 micro / nano powder has a length of 500 nm to 1200 nm and a width of 57 nm to 120 nm; the rod-shaped VO2 micro / nano powder is specifically prepared according to the following steps: Vanadium pentoxide powder and oxalic acid dihydrate powder were added sequentially to deionized water and mixed thoroughly under magnetic stirring until the solution changed from yellow to green and finally to dark blue, resulting in a mixture. The mixture was then subjected to hydrothermal reaction at 220℃~240℃ for 1h~3h. After cooling to room temperature, the mixture was washed and centrifuged to obtain a dark black precipitate, i.e., VO2(B). The dark black precipitate was dried and then heat-treated at 500℃~550℃ for 30min~2h under an argon atmosphere to obtain rod-shaped VO2 micro / nano powder, i.e., VO2(M). The mass ratio of vanadium pentoxide powder to oxalic acid dihydrate powder is 1:(1.25~1.6); the mass ratio of vanadium pentoxide powder to deionized water is 1g:(40~50)mL.

2. The dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance according to claim 1, characterized in that... The solvent is water, xylene, alcohol solvents, ketone solvents, ester solvents, or dichloromethane.

3. The dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance according to claim 2, characterized in that... The adhesive is a solvent-based resin or a water-soluble resin; the solvent-based resin is Karton resin, polyamide resin, phenolic resin or vinyl resin; the water-soluble resin is waterborne polyurethane, acrylic resin or epoxy resin.

4. A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance according to claim 1, characterized in that... The dispersant is a polystyrene-maleic anhydride copolymer, a general-purpose silicone dispersant, or a POP polyether dispersant; the defoamer is a silicone defoamer.

5. A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance according to claim 1, characterized in that... The thickener is polyethylene oxide, polypropylene oxide, or hydroxyethyl cellulose; the leveling agent is polyether-modified polysiloxane, polyacrylate, or alkyl or phenyl-modified polysiloxane.

6. A dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance according to claim 1, characterized in that... The coating is applied to a high-reflectivity substrate and a high-emissivity substrate with a coating thickness of 0.7 mm to 1 mm; the high-reflectivity substrate is Al, Au, Ag, Mg, Ni, Zn or Cu; the high-emissivity substrate is SiC, Fe2O3, SiO2 or polyimide.

7. The method for preparing a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance as described in claim 1, characterized in that... It is done in the following steps: I. Preparation of rod-shaped VO2 micro / nano powder: Vanadium pentoxide powder and oxalic acid dihydrate powder were added sequentially to deionized water and mixed thoroughly under magnetic stirring until the solution changed from yellow to green and finally to dark blue, resulting in a mixture. The mixture was then subjected to hydrothermal reaction at 220℃~240℃ for 1h~6h. After cooling to room temperature, the mixture was washed and centrifuged to obtain a dark black precipitate, i.e., VO2(B). The dark black precipitate was dried and then heat-treated at 500℃~550℃ for 30min~2h under an argon atmosphere to obtain rod-shaped VO2 micro / nano powder, i.e., VO2(M). The mass ratio of vanadium pentoxide powder to oxalic acid dihydrate powder is 1:(1.25~1.6); the mass ratio of vanadium pentoxide powder to deionized water is 1g:(40~50)mL. II. Preparation of VO2 coatings: Weigh out 1 to 1000 parts by weight of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, 40 to 60 parts of defoamer, 1000 to 1999 parts of binder, 10 to 20 parts of thickener, and 10 to 20 parts of leveling agent. Mix 1 to 1000 parts of rod-shaped VO2 micro / nano powder, 800 to 1000 parts of solvent, 20 to 30 parts of dispersant, and 40 to 60 parts of defoamer evenly, and then pre-disperse to obtain a pre-dispersed slurry. Then add 1000 to 1999 parts of binder, 10 to 20 parts of thickener, and 10 to 20 parts of leveling agent to the pre-dispersed slurry for dispersion to obtain a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance.

8. The method for preparing a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance as described in claim 7, characterized in that... The washing and centrifugation described in step one specifically involves washing twice with deionized water, and then centrifuging for 8 to 10 minutes at a speed of 6000 to 8000 rpm. The drying described in step one specifically involves drying at a temperature of 60°C to 80°C for 4 to 8 hours.

9. The method for preparing a dynamic thermal management coating with temperature-adaptive thermal radiation regulation performance as described in claim 7, characterized in that... The pre-dispersion mentioned in step two specifically refers to pre-dispersion for 30 to 40 minutes at a rotation speed of 600 to 800 rpm; the dispersion mentioned in step two specifically refers to dispersion for 20 to 30 minutes at a rotation speed of 600 to 800 rpm.

Images