Aerosol self-organization light scattering shielding material and preparation method thereof

Abstract

The invention relates to the technical field of special functional materials, in particular to an aerosol self-organizing light scattering shielding material and a preparation method thereof.The aerosol self-organizing light scattering shielding material is prepared from, by weight, 52.0-55.0 parts of rare earth doped hollow microspheres, 12.0-15.0 parts of a thermochromic outer layer, 10.0-12.0 parts of a surface modification and charge stabilization system and 15.0-18.0 parts of an aerogel network, 3.0-3.0 parts of a carrier solution and a stabilizer; through an optimally designed rare earth doped hollow microsphere structure, gt, gt and gt are realized in a visible light wave band (400-700 nanometers); the Mie scattering efficiency is 98%, and an effective optical shielding barrier is formed.

Description

Technical Field

[0001] This invention relates to the field of special functional materials technology, specifically to aerosol self-organized light scattering shielding material and its preparation method. This material can generate efficient Mie scattering in the visible light band, while achieving attenuation of infrared radiation, and forms dynamic optical camouflage through the release of thermochromic particles, which can be applied to a new generation of active shielding equipment. Background Technology

[0002] With the rapid development of modern detection technology, traditional shielding materials face detection threats from multiple bands, directions, and methods. In particular, when multiple detection methods such as visible light, infrared, and radar work together, traditional single-function shielding materials can no longer meet actual needs.

[0003] Currently, shielding materials mainly include several categories such as microwave absorbing materials, optical shielding materials, and infrared shielding materials. Among them, CN109135531B discloses a rare earth-doped nano-indium tin oxide infrared shielding coating. This coating is prepared by liquid-phase chemical co-precipitation method to obtain rare earth-doped nano-indium tin oxide powder, and the surface is modified by coupling agent KH570. Although it has good infrared shielding performance, its shielding mechanism is mainly based on static coating, lacks controllability, and does not have the ability to shield scattering in the visible light band.

[0004] US8017036B1 discloses a method for preparing sub-10 nm rare earth-doped nanoparticles via gas-phase flame synthesis. This method can control the size and crystallinity of the nanoparticles, but the prepared particles are mainly used for luminescent materials and do not involve shielding applications. Furthermore, the problem of stable suspension of the particles in aerosols is not solved.

[0005] In recent years, MXene-based composite materials have attracted attention due to their excellent electrical conductivity and electromagnetic shielding properties. For example, some studies have reported... Nanofiber aerogels possess excellent sensing and thermal management properties, including some infrared shielding capabilities. However, these materials typically exist in a solid state, lacking the advantages of an aerosol form and making dynamic deployment and rapid response difficult.

[0006] Thermochromic materials, especially spiropyran derivatives, can undergo reversible structural changes in response to temperature stimuli, thereby altering their optical properties. However, the application of existing thermochromic materials in the field of shading still faces problems such as poor stability, slow response speed, and limited environmental adaptability.

[0007] Microfluidics provides an effective means for preparing monodisperse microspheres with controllable structures, but there are few research reports on its application in complex functional aerosol systems, especially in the field of shielding materials, where its application is still in its infancy.

[0008] The main problems with existing technologies include: 1) Traditional aerosol camouflage materials settle quickly and are difficult to maintain suspension for a long time; 2) It is difficult to balance light scattering efficiency and infrared attenuation performance; 3) They lack the ability to respond to environmental changes and cannot achieve dynamic camouflage effects; 4) Their performance stability is poor under complex environmental conditions.

[0009] Therefore, there is an urgent need to develop new aerosol shielding materials that can simultaneously meet the multi-functional requirements of efficient light scattering, infrared attenuation, long-term suspension stability, and dynamic camouflage, in order to meet the challenges of modern complex battlefield environments. Summary of the Invention

[0010] The purpose of this invention is to provide an aerosol self-organized light scattering shielding material and its preparation method. This material integrates scattering enhancement, infrared attenuation and dynamic camouflage functions through a multi-scale synergistic strategy, and has good suspension stability and environmental adaptability.

[0011] To achieve the above objectives, the present invention provides an aerosol self-organized light scattering shielding material, characterized in that the material comprises the following components in parts by weight: 52.0-55.0 parts of rare earth-doped hollow microspheres, 12.0-15.0 parts of a thermochromic outer layer, and 10.0-12.0 parts of a surface modification and charge stabilization system. 15.0-18.0 parts of aerogel network, 3.0-3.0 parts of carrier solution and stabilizer.

[0012] Preferably, the rare earth-doped hollow microspheres are composed of a silica shell material, rare earth dopants, and hollow nucleation agents, specifically comprising the following components in parts by weight: 35.0-40.0 parts of silica shell material, 10.0-12.0 parts of rare earth dopants, and 7.0-3.0 parts of hollow nucleation agents. The silica shell material is amorphous silica with a particle size of 5-15 nanometers, a specific surface area of ​​200-400 square meters / gram, and a purity ≥99.8%. The rare earth dopants include erbium trioxide, ytterbium trioxide, and neodymium trioxide in a weight ratio of 5:5:2. The hollow nucleation agents are polystyrene microspheres with an average diameter of 100-200 nanometers and a monodispersity coefficient variation of <5%.

[0013] Preferably, the thermochromic outer layer is composed of a spiropyran derivative, a methyl methacrylate copolymer matrix, and a crosslinking agent, specifically comprising the following components in parts by weight: 6.0-8.0 parts of the spiropyran derivative, 4.0-5.0 parts of the methyl methacrylate copolymer matrix, and 2.0-2.0 parts of the crosslinking agent. The spiropyran derivative is hydroxy{8-[hydroxy(oxomyl)nitrogeno group]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxomylprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxomyl)ammonium; the methyl methacrylate copolymer matrix has an average molecular weight of 120,000-180,000 g / mol and a glass transition temperature of 105-120°C; and the crosslinking agent is ethylene glycol dimethacrylate.

[0014] Preferably, the surface modification and charge stabilization system comprises a quaternary ammonium salt, a zwitterionic silane, and an ionic liquid, specifically including the following components in parts by weight: 5.0-6.0 parts of quaternary ammonium salt, 2.0-3.0 parts of zwitterionic silane, and 3.0-3.0 parts of ionic liquid. The quaternary ammonium salt is trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, the zwitterionic silane is 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonium)propane-1-sulfonate, and the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate.

[0015] Preferably, the Aerogel network is composed of It consists of a silica sol for aerogels, specifically comprising the following components in parts by weight: 8.0-10.0 parts, and 7.0-8.0 parts of silica sol for aerogel. It is a partially oxidized two-dimensional sheet structure with a lateral dimension of 1-5 micrometers and a thickness of 1-3 nanometers. The surface terminal groups are -OH, -O and -F. The silica sol used for aerogel is an aqueous suspension of 40% by weight with a particle size of 12-15 nanometers and a pH value of 9.2-9.9.

[0016] The present invention also provides a method for preparing the above-mentioned aerosol self-organized light scattering shielding material, characterized by comprising the following steps: (1) Synthesis of rare earth-doped hollow microspheres via microfluidics; (2) Synthesis of hydroxy{8-[hydroxy(oxylidene)nitrogenate radical]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxylideneprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxylidene)ammonium thermochromic compounds; (3) Applying a thermochromic coating to the surface of rare earth-doped hollow microspheres; (4) Preparation of partially oxidized ; (5) Surface modification of microspheres using quaternary ammonium salts and zwitterionic silanes; (6) Formation Aerogel composite materials; (7) Prepare the final aerosol system formulation.

[0017] The beneficial effects of this invention are: 1. Achieved high efficiency Mie scattering: Through optimized design of rare earth-doped hollow microsphere structure, a Mie scattering efficiency of >98% was achieved in the visible light band (400-700 nm), forming an effective optical shielding barrier.

[0018] 2. Excellent infrared attenuation performance: By utilizing the high thermal neutron cross section of rare earth ions and the electromagnetic absorption characteristics of MXene, >90% infrared radiation attenuation is achieved in the wavelength range of 1.0-8.0 micrometers, covering the key atmospheric window band.

[0019] 3. Achieved long-term suspension stability: Through the synergistic effect of charge self-organization mechanism and physical barrier of aerogel network, the suspension time of aerosols was extended to ≥10 hours, and the sedimentation rate was reduced to meters per second, significantly exceeding traditional aerosol systems.

[0020] 4. Features dynamic optical camouflage: When the ambient temperature exceeds 35℃, the thermochromic material can be released and reassembled into dynamic camouflage patches, achieving an adaptive response to environmental changes with a reaction time of <5 seconds.

[0021] 5. Demonstrates broad environmental adaptability: Maintains stable performance in a temperature range of -20 to 60℃ and relative humidity of 20% to 90%, making it suitable for complex and varied real-world application scenarios.

[0022] In summary, this invention, through a multi-scale collaborative strategy, successfully solves the problems of poor stability, limited functionality, and limited environmental adaptability faced by traditional aerosol shielding materials, providing a material basis for the next generation of active shielding equipment. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments. Those skilled in the art should understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0024] Example 1: Basic Aerosol Self-Organized Light Scattering Shielding Material This embodiment provides an aerosol self-organized light scattering shielding material, which, by weight, consists of the following components: Rare earth-doped hollow microspheres (52.0 parts), thermochromic outer layer (12.0 parts), surface modification and charge stabilization system (10.0 parts). 15.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0025] The rare-earth-doped hollow microspheres are composed of the following components by weight: 35.0 parts silica shell material, 10.0 parts rare-earth dopant, and 7.0 parts hollow nucleation agent. The silica shell material used is amorphous silica produced by Sigma-Aldrich, with a particle size of 5 nm, a specific surface area of ​​200 m² / g, and a purity of 99.8%. The rare-earth dopant includes erbium trioxide (99.9% purity, particle size <100 nm), ytterbium trioxide (99.9% purity, particle size <100 nm), and neodymium trioxide (99.9% purity, particle size <100 nm) produced by Alfa Aesar, in a weight ratio of 5:5:2. The hollow nucleation agent is polystyrene microspheres produced by Polysciences, with an average diameter of 100 nm and a monodispersity coefficient variation of 4.5%.

[0026] The thermochromic outer layer is composed of the following components in parts by weight: 6.0 parts of spiropyran derivative, 4.0 parts of methyl methacrylate copolymer matrix, and 2.0 parts of crosslinking agent. The spiropyran derivative is hydroxy{8-[hydroxy(oxynyl)nitrogenocyanate]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxoylideneprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxoylidene)ammonium, synthesized by the method of this invention. The methyl methacrylate copolymer matrix is ​​polymethyl methacrylate produced by Sigma-Aldrich, with an average molecular weight of 120,000 g / mol and a glass transition temperature of 105°C. The crosslinking agent is ethylene glycol dimethacrylate produced by Sigma-Aldrich, with a purity of 98% and containing 100-150 ppm hydroquinone monomethyl ether as an inhibitor.

[0027] The surface modification and charge stabilization system comprises the following components in parts by weight: 5.0 parts quaternary ammonium salt, 2.0 parts zwitterionic silane, and 3.0 parts ionic liquid. The quaternary ammonium salt is trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, a 50-part methanol solution with a density of 0.9-1.0 g / mL (25°C), manufactured by Gelest. The zwitterionic silane is 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonium)propane-1-sulfonate, manufactured by Gelest, with a purity ≥95% and an appearance of white to slightly white powder. The ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate (product number 70956), manufactured by Sigma-Aldrich, with a purity ≥98%, water content <1000 ppm, and halide content <100 ppm.

[0028] The aerogel network consists of the following components in parts by weight: 8.0 parts, and 7.0 parts of silica sol for aerogel. Among them, The partially oxidized two-dimensional sheet-like structure prepared by the method of this invention has a lateral dimension of 1 micrometer and a thickness of 1 nanometer, with surface terminal groups of -OH, -O, and -F. The silica sol used for the aerogel is manufactured by Sigma-Aldrich. HS-40 is a 40% aqueous suspension with a particle size of 12 nanometers and a pH of 9.2.

[0029] The carrier solution and stabilizer consist of the following components in parts by weight: 1.0 part modified guar gum, 1.0 part glycerol, and 1.0 part pH buffer system. The modified guar gum is manufactured by Solvay. C-13S, degree of substitution 0.1, viscosity of 1 part solution 2500 centipoise. Glycerol is glycerol produced by Sigma-Aldrich, purity ≥99.5%, water content ≤0.5%. The pH buffer system consists of disodium hydrogen phosphate and potassium dihydrogen phosphate produced by Sigma-Aldrich, both analytical grade, purity ≥99.0%.

[0030] The preparation method of this aerosol self-organized light scattering shielding material includes the following steps: (1) Synthesis of rare earth-doped hollow microspheres via microfluidics First, prepare the three fluid phases for microfluidic processing. Inner oil phase: Disperse polystyrene microspheres (1.0 g) in 50 centistokes silicone oil (99.0 g) and treat with an ultrasonic homogenizer (frequency 20 kHz, amplitude 40%) for 15 minutes. Intermediate phase: In a 250 mL beaker, mix deionized water (80.0 g) and ethanol (10.0 g), and add tetraethyl orthosilicate (6.0 g) while stirring at 600 rpm. Then add rare earth nitrates: erbium nitrate pentahydrate (1.0 g), ytterbium nitrate pentahydrate (0.5 g), and neodymium nitrate hexahydrate (0.5 g). Add Tween 80 (0.2 g) and stir at room temperature for 30 minutes. Adjust the pH to 3.0-3.5 using dilute nitric acid. External oil phase: Mix 500 centis silicone oil (96.0 g) with Span 80 (4.0 g) and stir at 400 rpm for 30 minutes.

[0031] Next, assemble the glass capillary microfluidic device by inserting two pointed glass capillaries (80 μm inner diameter) into the ends of a square glass capillary (1 mm inner width). Connect the fluid reservoir to the syringe pump and set the following flow rates: inner oil phase 1.2 mL / h, intermediate phase 4.5 mL / h, and outer oil phase 12.0 mL / h. Collect the resulting double emulsion droplets in a collection tank containing a 0.5% polyvinyl alcohol solution. Operate the system at room temperature (20–25 °C) for 4 hours to collect sufficient droplets.

[0032] The collected emulsion was then transferred to a sealed container, and ammonium hydroxide solution (28%–30%, 2.0 mL) was added to catalyze the hydrolysis and condensation of tetraethyl orthosilicate. The emulsion was aged for 24 hours with gentle stirring (100 rpm) at 40 ± 2 °C. The aged emulsion was filtered and washed with a cyclohexane / ethanol mixture (1:1 volume ratio, 50 mL each time, 3 times) to remove silicone oil. The particles were dispersed in ethanol (100 mL), heated to 60 °C and held for 6 hours to extract the polystyrene core material. The mixture was centrifuged at 5000 rpm for 10 minutes, the supernatant was removed, and the mixture was washed three times with ethanol.

[0033] Finally, the washed particles were vacuum dried at 60°C for 12 hours, then transferred to a ceramic crucible and calcined in a tube furnace according to the following procedure: increasing from room temperature to 300°C at 2°C / min and holding for 1 hour; increasing from 300°C to 550°C at 1°C / min and holding for 4 hours; cooling to room temperature at 2°C / min. Calcination was carried out in air to ensure complete removal of the organic template and promote the crystallization of the rare earth dopants.

[0034] A thermochromic compound containing hydroxyl{8-[hydroxy(oxylidene)nitrogen cation]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxylideneprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxylidene)ammonium was synthesized, with the following structural formula:

[0035] In a 500 mL three-necked round-bottom flask equipped with a magnetic stirrer, reflux condenser, and nitrogen inlet, 16.7 g (0.10 mol) of 2-hydroxy-5-nitrobenzaldehyde and 200 mL of absolute ethanol were added. 3-(2,3,3-trimethyl-2,3-dihydro-1H-indol-1-yl)prop-1-ol (21.9 g, 0.10 mol) was added dropwise over 30 minutes while maintaining a temperature of 45–50 °C. The mixture was heated to reflux (78–80 °C) for 6 hours under a nitrogen atmosphere. The reaction mixture was cooled to room temperature, then cooled to 0–5 °C in an ice bath and held for 2 hours. The precipitated crystals were filtered, washed with cold ethanol (30 mL three times), and dried under vacuum at 40 °C for 24 hours to give the spiropyran intermediate. The yield was 85%–90% (32.2–34.1 g), pale yellow to beige crystals. The structural formula of 3-(2,3,3-trimethyl-2,3-dihydro-1H-indol-1-yl)prop-1-ol is as follows:

[0036] In a 500 mL three-necked round-bottom flask equipped with a magnetic stirrer, dropping funnel, and nitrogen inlet, a spiropyran intermediate (30.0 g, 0.079 mol) was dissolved in anhydrous dichloromethane (200 mL). Triethylamine (10.0 g, 0.099 mol) was added, and the solution was cooled to 0–5 °C in an ice bath. Methacrylamide chloride (9.2 g, 0.088 mol) was added dropwise over 1 hour, maintaining the temperature below 5 °C. The reaction mixture was allowed to warm to room temperature and stirred for an additional 12 hours under a nitrogen atmosphere.

[0037] The reaction mixture was washed with distilled water (100 mL three times), 0.1 M hydrochloric acid solution (50 mL twice), saturated sodium bicarbonate solution (50 mL twice), and finally with brine (50 mL). The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure at 40 °C. The crude product was purified by silica gel (60-120 mesh) column chromatography using toluene / ethyl acetate (9:1 v / v) as eluent. The yield was 75%–80% (27.0–28.8 g) as a pale yellow solid.

[0038] pass , The structure was confirmed by FTIR spectroscopy. ): , 7.21-7.15(m,1H), 6.94-6.85(m,3H), 6.76(d,J = 7.8 Hz,1H), 6.01(d,J = 10.4 Hz,1H), 5.89(s,1H), 5.57(s,1H), 4.15(t,J = 6.4 Hz,2H), 3.38-3.30(m,2H), 1.95(s,3H), 1.92-1.85(m,2H), 1.32(s,3H), 1.17(s,3H). FTIR(KBr): 2975,1718(C=O), , , Melting point: 152-155℃. UV-vis (ethanol): λmax = 355 nm (closed-ring form), 550 nm (open-ring form after UV irradiation).

[0039] (3) Applying thermochromic coatings to the surface of rare earth-doped hollow microspheres In a 250 mL three-necked round-bottom flask equipped with a magnetic stirrer, nitrogen inlet, and condenser, add 100 mL of tetrahydrofuran and purge with nitrogen for 15 minutes to remove oxygen. Add the synthesized hydroxy{8-[hydroxy(oxylidene)nitrogenohydrin]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxylideneprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxylidene)ammonium (8.0 g), methyl methacrylate (5.0 g), ethylene glycol dimethacrylate (2.0 g), and polyethylene glycol 400 (0.75 g). Stir at 400 rpm for 30 minutes under a nitrogen atmosphere to ensure complete dissolution. Add azobisisobutyronitrile (0.15 g) and continue stirring for 10 minutes.

[0040] Rare earth-doped hollow microspheres (15.0 g) were dispersed in the coating solution in an ice bath under ultrasonic conditions (40 kHz, 100 W) for 30 minutes to prevent premature polymerization. The dispersion was then transferred to a 500 mL jacketed reactor equipped with a mechanical stirrer, nitrogen inlet, and UV light source. The temperature was maintained at 20 ± 2 °C using a circulating water bath. The mixture was stirred at 300 rpm under a nitrogen atmosphere.

[0041] While continuously stirring, the dispersion was exposed to UV irradiation (wavelength 365 nm, intensity 10 mW / cm²) for 15 minutes. The stirring speed was then increased to 500 rpm, and UV irradiation was continued for an additional 15 minutes. The polymerization process was monitored by taking small samples and checking for viscosity increases.

[0042] Transfer the reaction mixture to a 1000 mL beaker and add 500 mL of ethanol to precipitate the coated microspheres. Stir the mixture for 10 minutes and allow precipitation for 30 minutes. Decant the supernatant and wash the precipitate with ethanol (3 times, 100 mL each time). Collect the coated microspheres by centrifugation at 4000 rpm for 10 minutes. Vacuum dry at 40 °C for 24 hours.

[0043] (4) Preparation of partially oxidized

[0044] In a 1000 mL PTFE beaker, add deionized water (400 mL) and lithium fluoride (10.0 g). Stir the mixture for 10 minutes to dissolve the lithium fluoride. Slowly add hydrochloric acid (100 mL) while stirring. Note: This step should be performed in a well-ventilated fume hood, as hydrogen fluoride gas may be generated. Continue stirring for 30 minutes to obtain a homogeneous etching solution.

[0045] Gradually within 15 minutes Phase powder (10.0 g) was added to the etching solution to minimize localized heating. The beaker was sealed with sealing film and stirred at 400 rpm for 48 hours at 35 ± 2 °C.

[0046] Centrifuge the etch mixture at 3500 rpm for 10 minutes. Pour off the supernatant and add 500 ml of deionized water. Stir for 10 minutes and centrifuge again at 3500 rpm for 10 minutes. Repeat the washing process 5 times until the pH of the supernatant reaches 6-7.

[0047] After the final centrifugation, add 500 mL of deionized water to the precipitate. Sonicate the mixture in an ice bath for 2 hours (40% amplitude, 2-second on / 1-second off pulse cycle). Centrifuge at 1500 rpm for 10 minutes to remove any unexfoliated particles. Collect the supernatant containing the exfoliated MXene nanosheets.

[0048] Centrifuge the MXene suspension at 8000 rpm for 20 minutes. Discard the supernatant and disperse the precipitate in ethanol (200 mL). Transfer the dispersion to a shallow glass dish (20 cm in diameter). Place the dish in a humidity-controlled chamber set to 80% relative humidity (RH). Heat the room temperature to 200°C and maintain this condition for 2 hours. Allow the room temperature to cool naturally to room temperature (approximately 4 hours). Collect the partially oxidized MXene and store it under an argon atmosphere.

[0049] (5) Surface modification of microspheres using quaternary ammonium salts and zwitterionic silanes In a 500 mL glass beaker, add ethanol (320 mL) and deionized water (80 mL). Adjust the pH to 4.5-5.0 by adding glacial acetic acid (0.5 mL). Add trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride (50% methanol solution, 12.0 g, equivalent to 6.0 g of active substance). Add 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonium)propane-1-sulfonate (2.5 g) and stir until completely dissolved. Add 1-butyl-3-methylimidazolium hexafluorophosphate (3.5 g) and stir at 400 rpm for 30 minutes to form a homogeneous solution.

[0050] In a 1000 mL three-necked round-bottom flask equipped with a mechanical stirrer, condenser, and thermometer, add the surface modification solution. Heat the solution to 40 ± 2 °C. While stirring (300 rpm), add thermochromic coated microspheres (15.0 g) in batches over 15 minutes. Continue stirring at 40 °C for 24 hours to ensure complete surface modification.

[0051] Allow the reaction mixture to cool to room temperature. Centrifuge at 4000 rpm for 15 minutes. Discard the supernatant and wash the precipitate with an ethanol / water mixture (4:1 v / v, 200 mL). Repeat the centrifugation and washing process three times. Wash twice more with pure ethanol (200 mL). Vacuum dry the modified microspheres at 50 °C for 24 hours.

[0052] (6) Formation Aerogel composite materials Partially oxidized material was treated with ultrasound (40 kHz, 100 W) in an ice bath. Disperse 10.0 g in 200 mL of deionized water for 1 hour. Adjust the pH to 6.0-6.5 using 0.1 M ammonium hydroxide solution.

[0053] In a 500 mL beaker, add 160 mL of ethanol, 40 mL of deionized water, and 0.8 mL of 1 M hydrochloric acid. While stirring (500 rpm), add 20.0 g of tetraethyl orthosilicate dropwise. Stir the mixture at room temperature for 1 hour. Add... Add HS-40 (20.0 g) and continue stirring for another hour. The resulting sol should be clear or slightly translucent.

[0054] In a 1000 mL beaker, combine the MXene dispersion and silica sol at a 1:1 volume ratio. Stir the mixture at 300 rpm for 30 minutes. Add 15.0 g of surface-modified thermochromic microspheres and continue stirring for 1 hour. Transfer the mixture to a suitable mold (e.g., a cylindrical mold with a diameter of 5 cm). Cover the mold with perforated aluminum foil to allow for slow evaporation. Age the gel at room temperature for 48 hours, then age it for an additional 24 hours at 50 °C.

[0055] Carefully remove the gel from the mold. Immerse the gel in ethanol (500 ml) for 24 hours, changing the ethanol every 8 hours. Transfer the gel to acetone (500 ml), changing the acetone every 12 hours, for a total soaking time of 48 hours.

[0056] The acetone-soaked gel was placed in a supercritical fluid. In a desiccator. Using liquid at 15°C and 50 bar. Rinse for 2 hours to replace the acetone. Repeat the rinsing process 4 times every 4 hours. Increase the temperature to 40°C and the pressure to approximately 100 bar to achieve supercritical conditions. Maintain these conditions for 2 hours. Slowly depressurize at a rate of 1 bar / min to prevent the aerogel structure from collapsing.

[0057] (7) Preparation of the final aerosol system formulation In a 1000 mL beaker, add 950 mL of deionized water. Add disodium hydrogen phosphate (0.5 g) and potassium dihydrogen phosphate (0.3 g). Stir until completely dissolved. Adjust the pH to 7.0 ± 0.1 using 0.1 M sodium hydroxide or 0.1 M hydrochloric acid.

[0058] In a 2000 mL beaker, add 900 mL of buffer solution. While stirring (500 rpm), gradually add the modified guar gum (…). Add C-13S (1.0 g). Continue stirring for 2 hours to ensure complete hydration of the guar gum. Add glycerol (0.9 g) and stir for 30 minutes. Add 1-butyl-3-methylimidazolium hexafluorophosphate (1.0 g) and continue stirring for 1 hour. The solution should have a slightly viscous consistency.

[0059] Using a mortar and pestle, the functionalized microspheres were... The aerogel was ground into a fine powder. While stirring (400 rpm), the aerogel powder (17.5 g) was gradually added to the carrier solution. The stirring speed was increased to 800 rpm and continued for 1 hour. The mixture was homogenized using a high-shear homogenizer (10,000 rpm, 5 minutes). The dispersion was further treated with sonication (40 kHz, 80 W) in an ice bath for 15 minutes.

[0060] Filter the dispersion through a 5-micron membrane filter to remove any large aggregates. Check the pH and adjust to 6.8–7.2 if necessary. If needed, add deionized water to bring the total weight to 1000 g. Package the final formulation into pressurized containers suitable for aerosol dispensing.

[0061] The aerosol self-organized light scattering shielding material prepared in this embodiment exhibits excellent optical and stability properties. The Mie scattering efficiency in the visible light band (400-700 nm) reaches 98.2%, and the attenuation efficiency in the infrared band (1.0-8.0 μm) is 92.3%. The aerosol suspension time exceeds 10 hours, and the sedimentation rate is lower than [missing value]. Meters per second. The thermochromic response time is approximately 4.8 seconds, and it maintains stable performance over a temperature range of -20 to 60°C and relative humidity conditions of 20% to 90%.

[0062] Example 2: Aerosol self-organized light scattering shielding material with optimized rare earth doping ratio This embodiment provides an aerosol self-organized light scattering shielding material with an optimized rare earth doping ratio, which is composed of the following components by weight: Rare earth-doped hollow microspheres (53.5 parts), thermochromic outer layer (13.5 parts), surface modification and charge stabilization system (11.0 parts). 16.5 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0063] The rare-earth-doped hollow microspheres are composed of the following components by weight: 37.5 parts silica shell material, 11.0 parts rare-earth dopant, and 5.0 parts hollow nucleation agent. The silica shell material used is manufactured by Evonik Industries. The particles are 200, with a particle size of 10 nanometers, a specific surface area of ​​300 square meters per gram, and a purity of 99.9%. Rare earth dopants include erbium trioxide, ytterbium trioxide, and neodymium trioxide in a weight ratio of 4:4:3, further improving the attenuation performance in the mid-infrared band. The hollow nucleating agent is polystyrene microspheres with an average diameter of 150 nanometers and a monodispersity coefficient variation of 3.8 parts per unit area.

[0064] The thermochromic outer layer is composed of the following components in parts by weight: 7.0 parts spiropyran derivative, 4.5 parts methyl methacrylate copolymer matrix, and 2.0 parts crosslinking agent. The increased concentration of the spiropyran derivative enhances the intensity and durability of the thermochromic effect.

[0065] The surface modification and charge stabilization system consists of the following components in parts by weight: 5.5 parts quaternary ammonium salt, 2.5 parts zwitterionic silane, and 3.0 parts ionic liquid. Increasing the content of quaternary ammonium salt and zwitterionic silane further improves charge stability and environmental adaptability.

[0066] The aerogel network consists of the following components in parts by weight: 9.0 parts, and 7.5 parts silica sol for aerogel. Increased MXene content enhances electromagnetic shielding and infrared attenuation effects.

[0067] The composition of the carrier solution and stabilizer is the same as in Example 1.

[0068] The preparation method of this material is similar to that of Example 1, but the ratio of rare earth nitrates was adjusted in the microfluidic synthesis of rare earth-doped hollow microspheres: erbium nitrate pentahydrate (0.8 g), ytterbium nitrate pentahydrate (0.8 g), and neodymium nitrate hexahydrate (0.6 g). Furthermore, during the MXene preparation process, the oxidation conditions were controlled at 190°C, relative humidity at 85%, and the time was extended to 2.5 hours, resulting in MXene with an oxidation degree of approximately 20%, which achieved a better balance between conductivity and infrared absorption.

[0069] The material prepared in this embodiment has an improved attenuation efficiency of 95.7 parts per second in the infrared band (especially 3-5 micrometers), a shortened thermochromic response time of 4.2 seconds, and significantly improved stability in high humidity environments (RH 85%~90%).

[0070] Example 3: Aerosol Self-Organized Light Scattering Shielding Material to Enhance Suspension Stability This embodiment provides an aerosol self-organized light scattering shielding material with enhanced suspension stability, which is composed of the following components by weight: Rare earth-doped hollow microspheres (52.5 parts), thermochromic outer layer (14.0 parts), surface modification and charge stabilization system (12.0 parts). 18.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0071] This embodiment focuses on optimizing the surface modification and charge stabilization system and the aerogel network to enhance the suspension stability of the aerosol. The surface modification and charge stabilization system consists of the following components in parts by weight: 6.0 parts quaternary ammonium salt, 3.0 parts zwitterionic silane, and 3.0 parts ionic liquid. The zwitterionic silane content is increased to the upper limit to form a stronger hydration layer, providing additional steric stability. In aerogel networks The amount of silica sol used in the aerogel is increased to 10.0 parts, and the amount of silica sol used in the aerogel is 8.0 parts, forming a denser network structure and providing a more effective physical barrier.

[0072] During the preparation process, the reaction time of the surface modification step was extended to 36 hours, which enhanced the coverage and binding strength of the surface-modified groups. In the aerogel formation process, a low-temperature aging technique was used: pre-aging at 5°C for 24 hours, followed by aging at room temperature for 24 hours, and finally aging at 50°C for 24 hours. This three-stage aging process resulted in a more uniform microporous structure, which is beneficial for improving suspension stability.

[0073] In addition, a high-viscosity modified guar gum (viscosity of 3500 centipoise for 1% solution) was used in the preparation of the carrier solution, and a small amount of xanthan gum (0.05%) was added as a synergistic thickener to further enhance the stability of the carrier solution.

[0074] The material prepared in this embodiment has an extremely long suspension stability time, exceeding 15 hours, and a sedimentation rate as low as [missing information]. The material maintains a stable dispersion even under severe vibration conditions, with a speed of meters per second. Furthermore, its resistance to temperature fluctuations is enhanced, maintaining stable performance during temperature cycling tests from -20°C to 60°C.

[0075] Example 4: Aerosol Self-Organized Light Scattering Shielding Material for Enhanced Infrared Shielding Effect This embodiment provides an aerosol self-organized light scattering shielding material with enhanced infrared shielding effect, which is composed of the following components by weight: Rare earth-doped hollow microspheres (55.0 parts), thermochromic outer layer (12.5 parts), surface modification and charge stabilization system (10.5 parts). 18.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0076] This embodiment focuses on optimizing the composition and structure of rare-earth-doped hollow microspheres to enhance infrared shielding performance. The rare-earth-doped hollow microspheres are composed of the following components by weight: 40.0 parts silica shell material, 12.0 parts rare-earth dopant, and 3.0 parts hollow nucleation agent. The content of the rare-earth dopant is increased to the upper limit, and the ratio of the three rare-earth elements is adjusted to erbium:ytterbium:neodymium = 3:5:4. This ratio creates a wider absorption band in the near-infrared and mid-infrared bands.

[0077] In the microfluidic synthesis process, a multiple emulsification technique was employed to form droplets with a three-layer structure (O / W / O / W / O), ultimately preparing multilayer hollow microspheres with an onion-like structure. This structure exhibits multiple scattering and absorption effects in different infrared bands. The calcination temperature was also optimized, employing a two-stage calcination process: first, calcination at 450℃ for 2 hours, followed by calcination at 600℃ for 3 hours. This process promoted the uniform distribution of rare earth elements in the silicon framework, forming more effective infrared absorption centers.

[0078] Furthermore, the oxidation level of MXene is controlled within the range of 25% to 30%. This oxidation level allows for enhanced absorption in the mid- and far-infrared bands while maintaining good conductivity. MXene and The interface was optimized by adding a small amount of silane coupling agent (γ-aminopropyltriethoxysilane, 0.5%) during the sol-gel process, resulting in stronger interfacial coupling, which is beneficial to improving photothermal conversion efficiency.

[0079] The material prepared in this embodiment exhibits excellent attenuation performance across the entire infrared band (1.0-14.0 micrometers), with an attenuation efficiency exceeding 97.5%. In particular, the attenuation efficiency reaches 98.9% in the atmospheric window bands (3-5 micrometers and 8-14 micrometers), providing full-band infrared shielding protection.

[0080] Example 5: Aerosol Self-Organized Light Scattering Shielding Material with Rapid Thermochromic Response This embodiment provides an aerosol self-organized light scattering shielding material with rapid thermochromic response, which is composed of the following components by weight: Rare earth-doped hollow microspheres (52.0 parts), thermochromic outer layer (15.0 parts), surface modification and charge stabilization system (11.0 parts). 19.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0081] This embodiment focuses on optimizing the composition and structure of the thermochromic outer layer to achieve a faster thermochromic response. The thermochromic outer layer consists of the following components in parts by weight: 8.0 parts of spiropyran derivative, 5.0 parts of methyl methacrylate copolymer matrix, and 2.0 parts of crosslinking agent. The spiropyran derivative content is increased to the upper limit, providing a stronger color change signal. Simultaneously, structural optimization was performed during the synthesis of hydroxy{8-[hydroxy(oxomyl)nitrogenocyanate]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxomylprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxomyl)ammonium. An additional nitro substituent was introduced at the 6-position of the chromene ring, lowering the ring-opening activation energy, reducing the color change temperature to 32°C, and shortening the response time.

[0082] In the application of thermochromic coatings, microemulsion polymerization technology was used instead of direct photopolymerization. First, spiropyran derivatives, methyl methacrylate, and a crosslinking agent were dissolved in an organic phase, then emulsified through high-speed shearing to form nanoscale droplets, followed by polymerization. This method resulted in a thinner and more uniform coating (approximately 15 nanometers thick), significantly reducing the heat transfer distance and accelerating the thermal response.

[0083] In addition, a small amount of phase change material (n-octadecane, 1%) was added to the coating system as a heat regulator. Its melting point (28°C) is lower than the color change temperature. When the ambient temperature rises, the phase change material absorbs heat and melts, promoting uniform heat distribution and accelerating the temperature response of the entire coating.

[0084] exist In aerogel networks, The content was increased to 10.0 parts, which enhanced the photothermal conversion efficiency of the material, enabling the material to absorb ambient heat more effectively and trigger a thermochromic reaction.

[0085] The material prepared in this embodiment exhibits an ultrafast thermochromic response speed, with a color change response time shortened to 2.3 seconds, far below the target value of 5 seconds. The color change process displays obvious non-linear characteristics, requiring only 1.5 seconds in the initial stage (0%–80% color change). This rapid response capability allows the material to adapt to sudden changes in ambient temperature in a timely manner, providing an immediate optical camouflage effect. Furthermore, the material also demonstrates excellent color change reversibility; after 100 temperature cycling tests, the color change efficiency remains above 95%.

[0086] Example 6: High Weather-Resistant Aerosol Self-Organized Light Scattering Shielding Material This embodiment provides a highly weather-resistant aerosol self-organized light scattering shielding material, which is composed of the following components by weight: Rare earth-doped hollow microspheres (54.0 parts), thermochromic outer layer (13.0 parts), surface modification and charge stabilization system (12.0 parts). 18.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0087] This embodiment focuses on optimizing the material's weather resistance, particularly its resistance to extreme temperatures, humidity, and ultraviolet radiation. In the rare-earth-doped hollow microspheres, the silica shell material is increased to 38.0 parts, forming a thicker protective shell (approximately 45 nanometers), which improves the mechanical strength and thermal stability of the microspheres. The rare-earth dopant content is 11.0 parts, and a small amount of cerium ions (5% of the total rare-earth content) is introduced as an antioxidant to prevent the oxidation of other rare-earth elements under high-temperature conditions.

[0088] In the thermochromic outer layer, an ultraviolet absorber (2-hydroxy-4-methoxybenzoylbenzene, 0.5%) and an antioxidant (2,6-di-tert-butyl-4-methylphenol, 0.3%) are added to protect the spiropyran compound from ultraviolet radiation and oxidative damage. Simultaneously, a core-shell polymer particle design is employed, encapsulating the spiropyran compound within a polymethyl methacrylate core and covering it with a polyacrylate shell. This structure provides additional protection for the sensitive spiropyran molecules.

[0089] In the surface modification and charge stabilization system, the zwitterionic silane content is increased to 3.0%, forming a stronger hydration layer and providing excellent moisture resistance. Simultaneously, a fluorinated silane (trifluoropropyltrimethoxysilane, 0.5%) is introduced as a hydrophobic modifier, enhancing the material's stability in high-humidity environments.

[0090] In the aerogel network, a composite reinforcement strategy was adopted. A small amount of alumina nanofibers (0.8%) was added during the preparation process to form a three-dimensional cross-linked structure, which improved the mechanical strength and thermal stability of the aerogel. After supercritical drying, the aerogel was subjected to surface hydrophobic treatment by treating it with hexamethyldisilazane vapor at 120°C for 4 hours, which significantly improved the hydrophobicity and environmental stability of the aerogel.

[0091] A small amount of betaine (0.2%) was added to the carrier solution as a compatibility enhancer, which improved the stability of the carrier solution under extreme temperature conditions.

[0092] The material prepared in this embodiment exhibits excellent weather resistance, maintaining stable performance during temperature cycling tests from -40 to 80°C and remaining in effective working condition under relative humidity conditions of 10% to 95%. After 200 hours of continuous exposure to simulated solar radiation (including the ultraviolet portion), the material's light scattering efficiency and thermochromic properties decreased by less than 5%, demonstrating excellent long-term stability. In salt spray tests (5% NaCl solution, 35°C, 72 hours), the material maintained good dispersibility and functionality, demonstrating its application potential in marine environments.

[0093] Comparative Example 1: Rare Earth-Free Aerosol Light Scattering Materials This comparative example prepared aerosol light scattering material without rare earth doping, which consisted of the following components by weight: 52.0 parts of undoped hollow silica microspheres, 12.0 parts of thermochromic outer layer, and 10.0 parts of surface modification and charge stabilization system. 15.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0094] The undoped hollow silica microspheres contain no rare earth elements and consist only of a silica shell and a hollow nucleating agent. The preparation method is the same as in Example 1, but the step of adding rare earth nitrates is omitted.

[0095] Test results show that although the material still possesses some scattering capability in the visible light band (scattering efficiency of approximately 72.5%), it is significantly lower than the 98.2% of Example 1. An even more pronounced difference is observed in the infrared band, where the infrared attenuation efficiency of Comparative Example 1 is only 45.3%, far lower than the 92.3% of Example 1. This result fully demonstrates that rare earth doping is crucial for enhancing the optical performance of materials in the visible and infrared bands, especially the high thermal neutron cross-section of rare earth elements plays a decisive role in the attenuation of infrared radiation.

[0096] Comparative Example 2: Aerosol Masking Material Without Thermochromic Components This comparative example prepared an aerosol masking material without thermochromic components, which consisted of the following components by weight: Rare earth-doped hollow microspheres (64.0 parts), surface modification and charge stabilization system (10.0 parts). 23.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0097] The material preparation process omits the application step of the thermochromic outer layer, and accordingly increases the amount of rare earth-doped hollow microspheres and... The proportion of aerogel networks.

[0098] Test results show that the material performs well in visible light scattering and infrared attenuation, but completely lacks responsiveness to changes in ambient temperature. In simulated heat source proximity tests, the material failed to adjust its optical properties to adapt to environmental changes, exhibiting fixed optical characteristics. In contrast, Example 1 rapidly transitions to a colored state (purple) upon heat source proximity, providing additional optical camouflage, and returns to its original state after the heat source is removed. This dynamic responsiveness is a key characteristic for adapting to complex and changing environments, demonstrating the important role of thermochromic components in enhancing the environmental adaptability of materials.

[0099] Comparative Example 3: Aerosol Masking Material Without Surface Modification This comparative example prepared an aerosol masking material without surface modification, which, by weight, consisted of the following components: Rare earth-doped hollow microspheres (52.0 parts), thermochromic outer layer (12.0 parts), 33.0 parts of aerogel network, 3.0 parts of carrier solution and stabilizer.

[0100] The surface modification step was omitted in the preparation process of this material, and the thermochromic coating microspheres were directly used to form aerogel composite materials.

[0101] Test results showed that the initial optical properties of the material were similar to those of Example 1, but its suspension stability was significantly reduced. In the static test, the aerosol of Comparative Example 3 began to show obvious stratification within 2 hours, and almost completely settled after 4 hours. The calculated settling rate was... The speed is meters per second, which is nearly two orders of magnitude higher than that of Example 1. Surface potential measurements of the microspheres show that the surface potential of the unmodified microspheres is only +5 to +10 millivolts, far lower than the +30 millivolts of Example 1, resulting in insufficient electrostatic repulsion between particles, making them prone to aggregation and sedimentation.

[0102] Furthermore, the material exhibits a significant performance degradation in high humidity environments (RH > 70%), with a slower thermochromic response and reduced visible light scattering efficiency. This is because the unmodified microspheres are highly hydrophilic, readily absorbing ambient moisture and affecting optical performance. These results demonstrate the crucial role of surface modification and charge stabilization systems in maintaining the long-term suspension stability and environmental adaptability of aerosols.

[0103] Comparative Example 4: None Aerosol masking material of aerogel network This comparative example prepared products without... The aerosol shielding material of the aerogel network, by weight, consists of the following components: The composition includes 67.0 parts of rare earth-doped hollow microspheres, 15.0 parts of thermochromic outer layer, 15.0 parts of surface modification and charge stabilization system, and 3.0 parts of carrier solution and stabilizer.

[0104] The preparation of this material omits the steps of MXene preparation and aerogel formation, and directly disperses the surface-modified thermochromic microspheres in the carrier solution.

[0105] Test results show that the material has good initial light scattering properties, but its suspension stability and infrared attenuation ability are significantly reduced. In the suspension stability test, the aerosol in Comparative Example 4 showed significant sedimentation after 6 hours, and the calculated sedimentation rate was... The speed was m / s, which, while better than Comparative Example 3, was still significantly higher than Example 1. This result indicates that although surface modification can provide charge stability, the physical barrier provided by the aerogel network is also an important factor in maintaining long-term suspension stability.

[0106] In infrared attenuation tests, Comparative Example 4 showed an attenuation efficiency of only 65.8% in the 2-6 micrometer band, far lower than the 92.3% of Example 1. This is due to the lack of MXene contribution, resulting in the loss of the broad-spectrum electromagnetic absorption and plasmon effects provided by MXene. Furthermore, the thermochromic response of this material was also slow, possibly due to the lack of MXene's photothermal conversion effect, which slowed the material's response to changes in ambient temperature.

[0107] The results of comparative examples 1-4 show that there is a significant synergistic effect among the components of the aerosol self-organized light scattering shielding material proposed in this invention. Rare earth doping provides efficient light scattering and infrared attenuation capabilities, the thermochromic component endows the material with responsiveness to changes in ambient temperature, and the surface modification system ensures the charge stability of the aerosol. Aerogel networks further enhance the material's suspension stability and infrared shielding performance through physical barrier and electromagnetic absorption. These components are indispensable and together constitute a multifunctional, high-performance shielding system.

[0108] To comprehensively evaluate the performance of the aerosol self-organized light scattering shielding material of the present invention, the following tests were conducted: 1. Light scattering efficiency test The scattering efficiency of materials in the 400-700 nm wavelength range was measured using an integrating sphere spectrophotometer. Test conditions: xenon lamp, 150 W; integrating sphere diameter 150 mm, inner wall coated with barium sulfate; sample cell 1 cm × 1 cm quartz cuvette; aerosol concentration 0.1 g / L.

[0109] 2. Infrared attenuation test The transmission and reflection spectra of the material in the 1.0–14.0 μm wavelength range were measured using a Fourier transform infrared spectrometer. Test conditions: 4 cm⁻¹ resolution. The number of scans was 32; the sample cell was a KBr window gas cell with a path length of 10 cm; the aerosol concentration was 0.1 g / L. The attenuation efficiency was calculated as 1 - (transmittance + reflectance).

[0110] 3. Suspension stability test Aerosol samples were placed in a transparent container, and under static conditions, particle concentration changes at different heights were monitored using a laser scattering particle size analyzer. Test conditions: container height 20 cm, diameter 5 cm; measurement heights 5 cm, 10 cm, and 15 cm from the bottom; monitoring time 24 hours, with data recorded every 30 minutes. Settling rate was calculated through data fitting.

[0111] 4. Thermochromic response test Using a self-made thermal response testing device, aerosol samples were placed in a temperature-controlled chamber, and changes in optical absorption were monitored in real time using a visible spectrophotometer. Testing conditions: initial temperature 25℃, rapidly heated to 40℃ (heating rate 5℃ / second); monitoring wavelength 550 nm (maximum absorption wavelength of the open-ring form of spiropyran); response time was defined as the time required for absorbance to reach 90% of its steady-state value.

[0112] 5. Environmental adaptability test Aerosol samples were placed in an environmental simulation chamber to test their performance stability under different temperature and humidity conditions. Temperature testing range: -40 to 80℃, in 10℃ increments; Humidity testing range: 10% to 95% RH, in 15% RH increments. Light scattering efficiency, infrared attenuation efficiency, and thermochromic response time of the material were measured at each condition point.

[0113] 6. Weather resistance test Accelerated weathering tests were conducted using a xenon lamp aging chamber. Test conditions: illumination intensity of 1000 watts / square meter, including UV-A and UV-B components; temperature cycling of 25-60℃; relative humidity cycling of 30%~80% RH; test cycle of 200 hours, with performance changes measured every 50 hours.

[0114] 7. Dynamic optical camouflage effect test The dynamic camouflage effect of materials in a simulated heat source environment was evaluated using thermal imaging and visible light imaging systems. Test conditions: background temperature 25°C, target heat source temperature 40°C; observation distance 5 meters; imaging system included an 8-14 micrometer thermal imager and a 400-700 nanometer visible light camera.

[0115] The main performance test results of each embodiment and comparative example are shown in Table 1:

[0116] As can be seen from Table 1, all embodiments of the present invention exhibit excellent overall performance, particularly in terms of visible light scattering efficiency, infrared attenuation efficiency, suspension stability, and thermochromic response, all of which meet or exceed the expected targets. In contrast, the comparative examples show significant deficiencies in their respective performance aspects due to the lack of certain key components.

[0117] Through in-depth analysis of the test results, the following conclusions can be drawn: 1. Synergistic Effect of Multiple Components: Significant synergistic effects exist among the components of this invention, collectively forming a highly efficient, multifunctional shielding system. Rare earth doping provides fundamental light scattering and infrared attenuation capabilities, the thermochromic component endows the material with environmental responsiveness, and the surface modification system ensures charge stability. Aerogel networks provide physical barriers and additional electromagnetic absorption.

[0118] 2. Importance of structural optimization: By optimizing the structure of each component (such as rare earth doping ratio, spiropyran molecule design, surface modification method, aerogel network morphology, etc.), the overall performance of the material can be significantly improved. In particular, the optimizations in Examples 2-6 for different performance aspects demonstrate that the present invention has a broad performance controllability.

[0119] 3. Multi-scale design strategy: The present invention adopts a multi-scale design strategy from the molecular scale (spiropyran molecular structure), nanoscale (rare earth doping, surface modification) to the microscale (aerogel network structure), which effectively solves the problems of poor stability, single function and limited environmental adaptability faced by traditional aerosol shielding materials.

[0120] 4. Environmental adaptability and weather resistance: The material of the present invention maintains stable performance under a wide range of temperature and humidity conditions. In particular, Example 6 demonstrates excellent weather resistance, which provides a guarantee for the application of the material in real complex environments.

[0121] In summary, the aerosol self-organized light scattering shielding material provided by this invention achieves an organic combination of multiple functions, such as efficient light scattering, infrared attenuation, long-term suspension stability, and dynamic thermochromic camouflage, through multi-component synergy, multi-scale design, and structural optimization, providing a material basis for the next generation of active shielding equipment.

[0122] The aerosol self-organized light scattering shielding material of this invention has good industrial applicability and can be mass-produced using existing industrial equipment and processes. Specifically, the production capacity of the microfluidic synthesis of rare-earth-doped hollow microspheres can be increased by connecting multiple microfluidic chips in parallel or by using a microfluidic continuous flow reactor; the synthesis of the thermochromic compound can be carried out using standard organic synthesis processes; and surface modification and aerogel preparation can both be achieved on existing chemical industrial equipment.

[0123] Furthermore, the materials of this invention can be applied in a variety of ways and can be customized according to actual needs. For example, the shielding effect in a specific wavelength band can be optimized by adjusting the rare earth doping ratio; the color change temperature and color can be adjusted by changing the structure of the thermochromic compound; and the stability requirements under different environmental conditions can be met by optimizing the aerogel network structure.

[0124] The aerosol self-organized light scattering shielding material of the present invention can be applied to multiple fields such as military equipment shielding, special safety protection, and temporary barrier construction, and has broad application prospects and significant economic value.

[0125] This invention provides a novel aerosol self-organized light scattering shielding material and its preparation method. This material organically combines efficient Mie scattering, infrared attenuation, long-term suspension stability, and dynamic thermochromic camouflage functionality through a multi-scale synergistic strategy, achieving a scattering efficiency of >98% in the visible light band, an attenuation efficiency of >90% in the infrared band, suspension stability of ≥10 hours, and a thermochromic response time of <5 seconds. The material maintains stable performance within a temperature range of -20 to 60°C and relative humidity conditions of 20% to 90%, demonstrating excellent environmental adaptability and application potential.

[0126] By comparing the performance test results of different embodiments and comparative examples, the necessity and synergistic effect of each component of the present invention were verified, demonstrating the effectiveness of the multi-component, multi-scale design strategy in solving complex functional material problems. The aerosol self-organized light scattering shielding material of the present invention provides a material basis for next-generation active shielding equipment, exhibiting significant innovation, advancement, and practical value.

Claims

1. An aerosol self-organized light scattering shielding material, characterized in that, The material comprises the following components in parts by weight: Rare earth-doped hollow microspheres, 52.0-55.0 parts. Thermochromic outer layer: 12.0-15.0 parts. Surface modification and charge stabilization system, 10.0-12.0 parts. Aerogel network 15.0-18.0 parts, 3.0-3.0 parts carrier solution and stabilizer; The rare-earth-doped hollow microspheres are composed of a silica shell material, rare-earth dopants, and hollow nucleation agents. The thermochromic outer layer is composed of spiropyran derivatives, methyl methacrylate copolymer matrix, and crosslinking agents. The surface modification and charge stabilization system is composed of quaternary ammonium salts, zwitterionic silanes, and ionic liquids. Aerogel network is composed of It consists of a silica sol for aerogels, and the carrier solution and stabilizer consist of modified guar gum, glycerol and a pH buffer system.

2. The aerosol self-organized light scattering shielding material according to claim 1, characterized in that, The rare earth-doped hollow microspheres comprise the following components in parts by weight: 35.0-40.0 parts of silica shell material Rare earth dopant 10.0-12.0 parts, Hollow nucleating agent 7.0-3.0 parts; The silica shell material is amorphous silica with a particle size of 5-15 nanometers, a specific surface area of ​​200-400 square meters per gram, and a purity of ≥99.8%. The rare earth dopants include erbium trioxide, ytterbium trioxide, and neodymium trioxide in a weight ratio of 5:5:

2. The hollow nucleating agent is polystyrene microspheres with an average diameter of 100-200 nanometers and a monodispersity coefficient variation of <5%.

3. The aerosol self-organized light scattering shielding material according to claim 1, characterized in that, The thermochromic outer layer comprises the following components in parts by weight: Spiropyran derivatives, 6.0-8.0 parts, 4.0-5.0 parts of methyl methacrylate copolymer matrix, Crosslinking agent 2.0-2.0 parts; The spiropyran derivative is hydroxy{8-[hydroxy(oxynyl)nitrogenocyanate]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxonylprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxonyl)ammonium, the average molecular weight of the methyl methacrylate copolymer matrix is ​​120,000-180,000 g / mol, the glass transition temperature is 105-120℃, and the crosslinking agent is ethylene glycol dimethacrylate.

4. The aerosol self-organized light scattering shielding material according to claim 1, characterized in that, The surface modification and charge stabilization system comprises the following components in parts by weight: Quaternary ammonium salt 5.0-6.0 parts, 2.0-3.0 parts of zwitterionic silane, 3.0-3.0 parts of ionic liquid; The quaternary ammonium salt is trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, the zwitterionic silane is 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonium)propane-1-sulfonate, and the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate.

5. The aerosol self-organized light scattering shielding material according to claim 1, characterized in that, The The aerogel network comprises the following components in parts by weight: 8.0-10.0 copies 7.0-8.0 parts of silica sol for aerogels; The It is a partially oxidized two-dimensional sheet structure with a lateral dimension of 1-5 micrometers and a thickness of 1-3 nanometers. The surface terminal groups are -OH, -O and -F. The silica sol used for aerogel is an aqueous suspension with a weight percentage of 40%, a particle size of 12-15 nanometers, and a pH value of 9.2-9.

9.

6. A method for preparing the aerosol self-organized light scattering shielding material according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Synthesis of rare earth-doped hollow microspheres by microfluidics; (2) Synthesis of hydroxy{8-[hydroxy(oxylidene)nitrogenate radical]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxylideneprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxylidene)ammonium thermochromic compounds; (3) Applying a thermochromic coating to the surface of rare earth-doped hollow microspheres; (4) Preparation of partially oxidized ; (5) Surface modification of microspheres using quaternary ammonium salts and zwitterionic silanes; (6) Formation Aerogel composite materials; (7) Prepare the final aerosol system formulation.

7. The method according to claim 6, characterized in that, Step (1) involves the microfluidic synthesis of rare earth-doped hollow microspheres, including: a) Prepare the fluid phase for microfluidic processing. The inner oil phase is polystyrene microspheres dispersed in 50 centistokes silicone oil, the intermediate phase is an aqueous solution containing tetraethyl orthosilicate, rare earth nitrates and Tween 80, and the outer oil phase is 500 centistokes silicone oil containing Span 80. b) Assemble the glass capillary microfluidic device, setting the inner oil phase flow rate to 1.2 mL / h, the intermediate phase flow rate to 4.5 mL / h, and the outer oil phase flow rate to 12.0 mL / h. c) Collect the formed double emulsion droplets in a collection tank containing a 0.5% by weight polyvinyl alcohol solution; d) Add ammonium hydroxide solution to catalyze the hydrolysis and condensation of tetraethyl orthosilicate, and age at 40±2℃ for 24 hours; e) Wash with a cyclohexane / ethanol mixture to extract the polystyrene core material; f) Calcination at 550°C for 4 hours to ensure complete removal of the organic template and promote the crystallization of rare earth dopants.

8. The method according to claim 6, characterized in that, The step (2) synthesizes hydroxy{8-[hydroxy(oxylidene) nitrogenochemical radical]-3',3'-dimethyl-1'-{3-[(2-methyl-1-oxylideneprop-2-enyl)oxy]propyl}-1',3'-dihydrospiro[chromene-2,2'-indole]-6-yl}(oxylidene)ammonium thermochromic compounds, including: a) In a three-necked round-bottom flask, 2-hydroxy-5-nitrobenzaldehyde was mixed with absolute ethanol, and 3-(2,3,3-trimethyl-2,3-dihydro-1H-indol-1-yl)prop-1-ol was added dropwise with stirring. The mixture was refluxed for 6 hours under a nitrogen atmosphere. b) Cool, filter, wash and dry the resulting crystals to obtain the spiropyran intermediate; c) Dissolve the spiropyran intermediate in anhydrous dichloromethane, add triethylamine, add methacrylamide dropwise in an ice bath, and stir at room temperature for 12 hours; d) Wash the reaction mixture with water, dilute hydrochloric acid solution, saturated sodium bicarbonate solution, and brine; e) Dry the organic phase with anhydrous sodium sulfate, filter, and concentrate under reduced pressure; f) The crude product was purified by silica gel column chromatography to obtain a pale yellow solid.

9. The method according to claim 6, characterized in that, Step (4) prepares partially oxidized include: a) In a polytetrafluoroethylene beaker, mix deionized water with lithium fluoride and stir for 10 minutes to dissolve the lithium fluoride; b) Slowly add hydrochloric acid and continue stirring for 30 minutes to obtain a uniform etching solution; c) The phase powder was gradually added to the etching solution and stirred at 35±2℃ for 48 hours; d) Centrifuge and wash until the pH of the supernatant reaches 6-7; e) Disperse the precipitate in deionized water and sonicate it in an ice bath for 2 hours; f) Centrifuge at low speed to remove unpeeled particles and collect the supernatant containing peeled MXene nanosheets; g) Centrifuge the stripped MXene suspension, and disperse the precipitate in ethanol; h) Place the dispersion in an environment with 80% relative humidity and keep it at 200°C for 2 hours; i) Allow the material to cool naturally to room temperature, collect the partially oxidized MXene, and store it under an argon atmosphere.

10. The method according to claim 6, characterized in that, The step (6) forms Aerogel composite materials include: a) Prepare an MXene dispersion, partially oxidized Disperse in deionized water and adjust the pH to 6.0-6.5; b) To prepare silica sol, mix ethanol, deionized water and hydrochloric acid, add tetraethyl orthosilicate dropwise, stir for 1 hour, add colloidal silica and continue stirring; c) Mix the MXene dispersion and silica sol at a 1:1 volume ratio and stir for 30 minutes; d) Add the surface-modified thermochromic microspheres and continue stirring for 1 hour; e) Transfer the mixture to a suitable mold and age at room temperature for 48 hours, then at 50°C for 24 hours; f) Remove the gel from the mold and soak it in ethanol for 24 hours, then in acetone for 48 hours; g) Place the acetone-soaked gel in a supercritical fluid. In the dryer, at 15°C and 50 bar, the liquid... Rinse for 2 hours to replace the acetone; h) Increase the temperature to 40°C and the pressure to about 100 bar to achieve supercritical conditions; i) Maintain these conditions for 2 hours, then slowly depressurize at a rate of 1 bar / minute to prevent the aerogel structure from collapsing.

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