Indocyanine green photo-thermal heat-insulation energy-saving composite particle and preparation method thereof

Abstract

The invention discloses an indocyanine green photo-thermal heat-insulation energy-saving composite particle and a preparation method thereof. The preparation method comprises the following steps: firstly, carrying out amination treatment on the surfaces of vanadium dioxide nano particles so as to obtain aminated vanadium dioxide nano particles; then, the aminated vanadium dioxide nano particles and sulfonate particles of indocyanine green are subjected to a reaction, and the indocyanine green grafted vanadium dioxide nano particles are obtained. According to the invention, the defects of high phase change temperature, poor dispersity, poor stability under high-temperature and high-humidity conditions and the like of the traditional thermally induced phase change material vanadium dioxide are overcome. The prepared composite particles can realize phase change at a relatively low environment temperature, and have excellent dispersity and stability, and glass prepared from the composite particles has strong modulation capability on sunlight. In addition, the preparation method is simple and convenient in process and easy for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of functional nanomaterials for thermal insulation, specifically to an indocyanine green photothermal insulating and energy-saving composite particle and its preparation method. This composite particle achieves low-temperature phase change and high-efficiency thermal insulation through the synergistic effect of the photothermal effect of indocyanine green and the phase change characteristics of vanadium dioxide. It can be widely used in building doors and windows, automotive glass, refrigeration equipment windows, and other fields, exhibiting excellent modulation capabilities for sunlight and possessing both energy-saving and practical value. Background Technology

[0002] Driven by both global "dual carbon" goals and the increasing demand for building energy conservation, building doors and windows, as the main channels for heat exchange, directly determine building energy consumption levels through their insulation performance. Statistics show that energy loss through doors and windows accounts for 30% to 50% of total building energy consumption, with solar radiation heat gain (especially near-infrared light) being a core factor contributing to increased indoor temperatures and surges in air conditioning loads during summer. Therefore, developing intelligent insulation materials that combine high visible light transmittance with efficient infrared blocking performance has become a key breakthrough for reducing building energy consumption and achieving green building goals.

[0003] Vanadium dioxide (VO2), a thermotropic phase change material, is considered a promising material for intelligent solar energy regulation due to its unique "metal-insulator" phase transition properties. Below the phase transition temperature (low-temperature state), VO2 exhibits insulating properties, with high transmittance of visible light (≥80%) and high reflectance of infrared light (≥60%), ensuring indoor lighting and reducing heat loss in winter. Above the phase transition temperature (high-temperature state), VO2 transforms into a metallic state, exhibiting high absorption of infrared light (≥80%), effectively blocking solar radiation heat gain in summer. However, traditional VO2 materials face three major technical bottlenecks in practical applications, severely limiting their industrialization:

[0004] First, the phase transition temperature does not match the actual scenario. The phase transition temperature of natural VO2 is about 68℃, which is much higher than the daily ambient temperature of buildings (10~40℃). Even under the scorching sun in summer, the surface temperature of glass can only reach 45~55℃, which is still insufficient to trigger the VO2 phase transition. As a result, its infrared regulation function is in a "dormant" state in most scenarios and cannot play an actual heat insulation role.

[0005] Secondly, poor dispersibility leads to deterioration in optical performance. VO2 nanoparticles are rich in hydroxyl groups on their surface, resulting in extremely high surface energy. They easily aggregate in organic matrices (such as acrylic resins), forming micron-sized aggregates. These aggregates not only produce strong light scattering, causing a sharp drop in the material's visible light transmittance (from 80% to below 50%), but also disrupt the continuity of infrared blocking, causing fluctuations in thermal insulation performance exceeding 20%, failing to meet the requirements of architectural glass for both light transmittance and performance stability.

[0006] Third, its poor environmental stability limits its service life. VO2 has poor chemical stability. In high-temperature and high-humidity environments (such as the rainy season in southern China and coastal areas), it is easily oxidized by oxygen and moisture in the air to V2O5, which has no phase change characteristics. At the same time, the surface hydroxyl groups will adsorb moisture to form a water film, leading to a phase change temperature drift (increasing by more than 10°C) and a decrease in infrared blocking rate (decreasing by 15% to 30%). Typically, the thermal insulation performance of traditional VO2-based glass will decrease significantly after 1 to 2 years of use, making it difficult to meet the requirements of long-term use (≥10 years) for building materials.

[0007] To address the aforementioned problems, extensive research has been conducted in existing technological fields, but all have significant limitations:

[0008] Metal ion doping modification: by introducing W 6+ Mo 6+ Metal ions can reduce the phase transition temperature of VO2 to below 50°C, but doping with metal ions will destroy the crystal structure of VO2, resulting in a 30% to 40% decrease in its infrared modulation efficiency. Moreover, the doping process requires high-temperature sintering (above 800°C), which is energy-intensive and complex, making it unsuitable for large-scale production.

[0009] Traditional organic coating: VO2 is coated with common silane coupling agents (such as methyltrimethoxysilane). Although this can improve dispersibility, it cannot provide additional photothermal energy to assist phase transition and still cannot solve the core problem of excessively high phase transition temperature.

[0010] In summary, current technologies have not yet broken through the technical barrier of simultaneously achieving "low-temperature phase change, high light transmittance, and high stability." There is an urgent need to develop a VO2-based composite particle that can achieve low-temperature phase change without high-temperature doping, while also possessing excellent dispersibility and environmental stability, in order to meet the pressing demand for high-performance thermal insulation materials in the field of building energy conservation. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of traditional vanadium dioxide materials, such as high phase transition temperature, poor dispersibility, and weak environmental stability, and to provide an indocyanine green photothermal insulation and energy-saving composite particle and its preparation method.

[0012] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0013] (1) Add aminosilane coupling agent to ethanol aqueous solution and disperse it at room temperature for 5-30 min to obtain treatment solution. Then add vanadium dioxide nanoparticles and react at 60-70℃ for 5-7 h. After filtering the reaction solution, wash and filter it repeatedly with ethanol and aqueous solution and dry it at 50-60℃ to obtain amino-modified vanadium dioxide nanoparticles.

[0014] (2) Dissolve indocyanine green in an acidic buffer solution (pH 4-6), then add the aminated vanadium dioxide nanoparticles obtained in step (1), and react at 600-80℃ for 8-12 hours. Then filter the reaction solution, wash and filter it repeatedly with deionized water, and dry it at 50-60℃ to obtain indocyanine green grafted vanadium dioxide nanoparticles.

[0015] The aminosilane coupling agent is at least one of 3-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane. These coupling agents contain both an amino (-NH2) group and a siloxane group in their molecular structure. The siloxane group can be anchored to the VO2 surface through a condensation reaction, while the amino group provides an active site for the subsequent reaction with the sulfonate group of indocyanine green, thus achieving a "bridging" effect.

[0016] The mass ratio of ethanol to water is 4:1 to 8:1. A high ethanol ratio can reduce the surface tension of the solution and promote the uniform adsorption and hydrolysis of the coupling agent on the VO2 surface. The pH value is controlled at 3 to 6. Acidic conditions can catalyze the hydrolysis of siloxane groups and accelerate the formation of silanol groups, while avoiding premature protonation of amino groups (pH < 3 will cause amino groups to protonate to -NH3). + (This affects subsequent reactions with sulfonate ions); the mass fraction of the coupling agent is 1-3%, which ensures the formation of an aminated layer on the VO2 surface, thus ensuring sufficient grafting sites and avoiding particle aggregation due to excessive coupling agent.

[0017] The vanadium dioxide nanoparticles have a particle size of 20-100 nm, and the mass ratio of VO2 to coupling agent is 6:1-10:1. This ratio ensures that the coupling agent fully coats the VO2 surface. If the ratio of coupling agent is too high, it will cause the interaction between amino groups to induce aggregation. If the ratio is too low, the amino density will be insufficient, affecting the grafting amount of indocyanine green.

[0018] Utilizing the amino group (-NH2) in the aminosilane coupling agent and the sulfonate group (-SO3) in the indocyanine green molecule -A chemical reaction occurs, forming stable chemical bonds to achieve a firm grafting of indocyanine green onto the VO2 surface. The long-chain alkyl groups in the indocyanine green molecule are randomly and interwoven on the VO2 surface, forming a dense physical barrier that blocks the diffusion of oxygen and water molecules to the VO2 surface, preventing oxidation and hydrolysis. At the same time, the long-chain structure provides steric hindrance, inhibiting the aggregation between VO2 particles. The conjugated benzene ring in the indocyanine green molecule has strong chemical inertness, resisting chemical corrosion under high temperature and high humidity environments. Meanwhile, the π electron cloud of the benzene ring can form a weak interaction with the VO2 surface, further enhancing the grafting firmness. In addition, the conjugated structure of the benzene ring can enhance the absorption of near-infrared light by the composite particles (absorption wavelength 750-850 nm), improving the photothermal conversion efficiency.

[0019] The mass ratio of indocyanine green to aminated vanadium dioxide nanoparticles is 1:3 to 1:5. This ratio satisfies the photothermal conversion requirements while avoiding increased visible light absorption due to excessive grafting.

[0020] This invention also provides an indocyanine green photothermal insulation and energy-saving composite particle prepared by the above-described method. This indocyanine green photothermal insulation and energy-saving composite particle has the following performance characteristics:

[0021] (1) The composite particles utilize the near-infrared photothermal conversion capability of indocyanine green (absorption rate ≥85%, conversion efficiency ≥75%) to provide sufficient additional heat energy for the phase change of vanadium dioxide (VO2), reducing the phase change temperature from 68℃ of traditional VO2 to 32-38℃, precisely matching the daily ambient temperature of the building's indoor and outdoor environments.

[0022] (2) Indocyanine green molecules are grafted onto the surface of vanadium dioxide nanoparticles through chemical bonding (forming -NH-SO3- bonds) between amino groups (-NH2) and sulfonate groups (-SO3H). The long-chain structure of indocyanine green and the conjugated benzene ring form a dual protection of "physical barrier + chemical stability": the long chains interweave to form a dense barrier, reducing the diffusion rate of oxygen and moisture to the VO2 surface, while the chemical inertness of the benzene ring resists high temperature and high humidity corrosion, preventing VO2 from being oxidized to V2O5 without phase change.

[0023] The beneficial effects of this invention are as follows:

[0024] (1) Overcoming the pain point of high phase transition temperature: No metal ion doping is required (avoiding a 30%-40% decrease in infrared efficiency). The phase transition temperature can be reduced to the practical range by indocyanine green photothermal synergy, while retaining the original infrared regulation efficiency of VO2 (infrared blocking rate ≥85% after phase transition).

[0025] (2) Solve the problem of poor dispersibility: The steric hindrance effect replaces the single coating of traditional silane coupling agents, improves dispersibility, and takes into account both light transmittance and heat insulation.

[0026] (3) Overcoming the problem of weak stability: dual protection enhances anti-aging ability, breaks through the performance degradation bottleneck under high temperature and high humidity environment, and expands the application scenarios of VO2 materials (such as coastal areas and plum rain areas); (4) The heat-insulating and energy-saving glass made has excellent solar full spectrum control ability: before phase change (low temperature) visible light transmittance is 75%-82%, which meets the building lighting needs; after phase change (high temperature) infrared transmittance is ≤10%, infrared blocking rate is increased by ≥60%, which can reduce the solar radiation heat gain in summer by 30%-40% and reduce the air conditioning load;

[0027] (5) This invention uses liquid phase chemical reaction (maximum reaction temperature 80°C), without the need for high-temperature sintering (traditional doping requires above 800°C) or complex equipment (such as vacuum sputtering). The reaction conditions are mild and controllable, and there is no toxic solvent emission throughout the process, which meets the requirements of green production.

[0028] (6) Composite particles can be used not only for building windows and doors, but also for automotive windshields (requiring high light transmittance and anti-aging properties) and cold chain equipment windows (requiring low-temperature phase change control). Their low-temperature phase change characteristics can prevent automotive glass from overheating in summer, and their anti-aging ability can adapt to the temperature and humidity fluctuations of cold chain equipment. At the same time, the particles have good compatibility with resins, glass and other matrices, and can directly replace traditional thermal insulation materials without modifying existing production equipment. They have low application thresholds, strong compatibility and great market potential. Detailed Implementation

[0029] The present application will now be described in further detail with reference to the embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit the invention.

[0030] Example 1

[0031] Preparation of aminated vanadium dioxide nanoparticles: 1 g of 3-aminopropyltrimethoxysilane (aminosilane coupling agent) was added to 99 g of ethanol aqueous solution (ethanol:water = 4:1, pH = 3, aminosilane coupling agent mass fraction 1%), and stirred at 1000 rpm for 30 min at room temperature to obtain a treatment solution; 6 g of vanadium dioxide nanoparticles (particle size 20 nm, VO2 to coupling agent mass ratio 6:1) were added, transferred to a three-necked flask, and reacted at 60 °C for 7 h; after the reaction was completed, the mixture was vacuum filtered, washed 3 times each with ethanol and deionized water, and dried under vacuum at 50 °C for 6 h to obtain aminated VO2 particles A1.

[0032] Preparation of indocyanine green-grafted vanadium dioxide nanoparticles: 0.8 g of indocyanine green (pure) was dissolved in 100 mL of acidic buffer solution (pH = 4, acetic acid-sodium acetate system) and sonicated for 20 min until completely dissolved; 6 g of particles A1 (indocyanine green to aminated VO2 mass ratio 1:7.5, close to the upper limit of 1:5) was added, and the reaction was carried out at 60 °C for 12 h; the mixture was then vacuum filtered, washed with deionized water until pH = 7, and vacuum dried at 50 °C for 8 h to obtain composite particles B1.

[0033] Preparation of heat-insulating and energy-saving glass: 1g of particles B1 was mixed with 150g of acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), stirred at 1200rpm for 45min, and degassed under vacuum at -0.08MPa for 30min; poured into two 5mm thick float glass sheets (5mm apart), and irradiated with 200nm ultraviolet light for 60min to obtain glass C1.

[0034] Performance test results:

[0035] Composite particle B1: Phase transition temperature 38℃, placed in an 80℃ / 90%RH environment for 30 days, phase transition temperature change rate 2.8%, infrared blocking rate decrease 4.2%;

[0036] Glass C1: Visible light transmittance 82%, infrared transmittance before phase transition 28%, infrared transmittance after phase transition 9%.

[0037] Example 2

[0038] Preparation of aminated vanadium dioxide nanoparticles: 3g of N-(2-aminoethyl)-3-aminopropyltriethoxysilane was added to 97g of ethanol aqueous solution (ethanol:water = 8:1, pH = 6, coupling agent mass fraction 3%), and stirred at 800rpm for 5min at room temperature to obtain a treatment solution; 10g of VO2 nanoparticles (particle size 100nm, VO2 to coupling agent mass ratio 10:1) were added, and the reaction was carried out at 70℃ for 5h; after washing and drying, particles A2 were obtained.

[0039] Preparation of composite particles: 1.2 g of indocyanine green derivative (1,1'-dimethylindocyanine green) was dissolved in 100 mL of pH 6 citrate buffer and sonicated for 10 min; 10 g of A2 (indocyanine green to aminated VO2 mass ratio 1:8.3, close to 1:5) was added and reacted at 80 °C for 8 h; after washing and drying, particles B2 were obtained.

[0040] Glass preparation: 1g B2 was mixed with 200g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), stirred at 1500rpm for 30min, and degassed at -0.1MPa for 20min; poured into two 6mm glass pieces (10mm apart), and irradiated with 450nm ultraviolet light for 10min to obtain glass C2.

[0041] Performance test results:

[0042] Particle B2: Phase transition temperature 32℃, after being placed in a humid environment for 30 days, the phase transition temperature change rate is 2.1%, and the infrared blocking rate decreases by 3.8%.

[0043] Glass C2: Visible light transmittance 75%, infrared transmittance before phase transition 25%, infrared transmittance after phase transition 8%.

[0044] Example 3

[0045] Preparation of aminated VO2: 2g of γ-aminopropylmethyldiethoxysilane was added to 98g of aqueous ethanol solution (ethanol:water = 6:1, pH = 4.5, coupling agent mass fraction 2%) and stirred at 1200rpm for 20min at room temperature; 8g of VO2 (particle size 60nm, VO2 to coupling agent mass ratio 8:1) was added and reacted at 65℃ for 6h; after washing and drying, particles A3 were obtained.

[0046] Preparation of composite particles: Dissolve 1.0 g indocyanine green in 100 mL of pH 5 acetate buffer and sonicate for 15 min; add 8 g A3 (mass ratio 1:8, close to 1:5) and react at 70 °C for 10 h; wash and dry to obtain particles B3.

[0047] Glass preparation: 1g B3 was mixed with 180g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), stirred at 1300rpm for 35min, and degassed at -0.09MPa for 25min; poured into two 5mm glass pieces (7mm apart), and irradiated with 365nm ultraviolet light for 30min to obtain glass C3.

[0048] Performance test results:

[0049] Particle B3: Phase transition temperature 35℃, after being placed in a humid environment for 30 days, the phase transition temperature change rate is 2.5%, and the infrared blocking rate decreases by 4.0%.

[0050] Glass C3: Visible light transmittance 79%, infrared transmittance before phase transition 26%, infrared transmittance after phase transition 9%.

[0051] Example 4

[0052] Preparation of amination-modified VO2: 1.5 g of 3-aminopropyltriethoxysilane was added to 98.5 g of aqueous ethanol solution (ethanol:water = 5:1, pH = 4, coupling agent mass fraction 1.5%) and stirred at 900 rpm for 25 min at room temperature; 9 g of VO2 (particle size 40 nm, VO2 to coupling agent mass ratio 9:1) was added and reacted at 62 °C for 6.5 h; after washing and drying, particles A4 were obtained.

[0053] Preparation of composite particles: Dissolve 0.6 g of indocyanine green (pure) in 100 mL of pH 4.5 buffer solution and sonicate for 18 min; add 9 g of A4 (mass ratio 1:15, close to the lower limit of 1:3), react at 65 °C for 11 h; wash and dry to obtain particles B4.

[0054] Glass preparation: 1g B4 was mixed with 160g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), stirred at 1250rpm for 40min, and degassed at -0.085MPa for 28min; poured into two 4mm glass pieces (6mm apart), and irradiated with 300nm ultraviolet light for 45min to obtain glass C4.

[0055] Performance test results:

[0056] Particle B4: Phase transition temperature 37℃, after being placed in a humid environment for 30 days, the phase transition temperature change rate is 2.7%, and the infrared blocking rate decreases by 4.5%.

[0057] Glass C4: Visible light transmittance 81%, infrared transmittance before phase transition 29%, infrared transmittance after phase transition 10%.

[0058] Example 5

[0059] Preparation of amination-modified VO2: 0.8 g of 3-aminopropylmethyldimethoxysilane + 0.7 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (mixed coupling agent, total mass 1.5 g) were added to 98.5 g of ethanol aqueous solution (ethanol:water = 7:1, pH = 5, coupling agent mass fraction 1.5%), and stirred at 1100 rpm for 15 min at room temperature; 7.5 g of VO2 (particle size 30 nm, VO2 to coupling agent mass ratio 5:1, close to the lower limit of 6:1) were added, and the reaction was carried out at 68 °C for 5.5 h; after washing and drying, particles A5 were obtained.

[0060] Preparation of composite particles: 0.9 g of indocyanine green derivative (1,1'-diethylindocyanine green) was dissolved in 100 mL of pH 5.5 buffer solution and sonicated for 12 min; 7.5 g of A5 (mass ratio 1:8.3, close to 1:5) was added and reacted at 75 °C for 9 h; after washing and drying, particles B5 were obtained.

[0061] Glass preparation: 1g B5 was mixed with 170g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), stirred at 1400rpm for 32min, and degassed at -0.095MPa for 22min; poured into two 5mm glass pieces (8mm apart), and irradiated with 400nm ultraviolet light for 20min to obtain glass C5.

[0062] Performance test results:

[0063] Particle B5: Phase transition temperature 34℃, after being placed in a humid environment for 30 days, the phase transition temperature change rate is 2.3%, and the infrared blocking rate decreases by 3.9%.

[0064] Glass C5: Visible light transmittance 78%, infrared transmittance before phase transition 27%, infrared transmittance after phase transition 9.2%.

[0065] Example 6

[0066] Preparation of aminated VO2: 2.5 g of 3-aminopropyltriethoxysilane was added to 97.5 g of ethanol aqueous solution (ethanol:water = 4.5:1, pH = 3.5, coupling agent mass fraction 2.5%) and stirred at 950 rpm for 28 min at room temperature; 20 g of VO2 (particle size 80 nm, VO2 to coupling agent mass ratio 8:1) was added and reacted at 63 °C for 6.8 h; after washing and drying, particles A6 were obtained.

[0067] Preparation of composite particles: Dissolve 1.1g of indocyanine green in 100mL of pH 4.2 buffer solution and sonicate for 16min; add 20g of A6 (mass ratio 1:18.2, close to 1:3) and react at 68℃ for 10.5h; wash and dry to obtain particles B6.

[0068] Glass preparation: 1g B6 was mixed with 190g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), stirred at 1350rpm for 38min, and degassed at -0.088MPa for 26min; poured into two 6mm glass plates (9mm apart), and irradiated with 350nm ultraviolet light for 35min to obtain glass C6.

[0069] Performance test results:

[0070] Particle B6: Phase transition temperature 36℃, after being placed in a humid environment for 30 days, the phase transition temperature change rate is 2.6%, and the infrared blocking rate decreases by 4.3%.

[0071] Glass C6: Visible light transmittance 76%, infrared transmittance before phase transition 28%, infrared transmittance after phase transition 9.5%.

[0072] Comparative Example 1

[0073] Preparation of aminated VO2: Same as step 1 in Example 1, to obtain particle A1 (without subsequent indocyanine green grafting).

[0074] Glass preparation: 1g A1 was directly mixed with 150g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s), as in step 3 of Example 1, to obtain glass D1.

[0075] Performance test results:

[0076] Particle A1: Phase transition temperature 65℃ (without indocyanine green photothermal assistance), after being placed in a humid environment for 30 days, the phase transition temperature rises to 78℃ (oxidation due to lack of protection), and the infrared blocking rate decreases by 28%.

[0077] Glass D1: Visible light transmittance 60% (VO2 aggregation leads to light scattering), infrared transmittance 45% before phase transition, infrared transmittance 30% after phase transition (no low-temperature phase transition, weak infrared blocking).

[0078] Comparative Example 2

[0079] Physically mixed particles: 6g of unaminated VO2 nanoparticles (particle size 20nm) were directly mixed with 0.8g of indocyanine green and sonicated for 30min to obtain mixed particles BO2 (no chemical grafting, only physical adsorption).

[0080] Glass preparation: Same as step 3 in Example 1, mix 1g B02 with 150g acrylic resin precursor liquid (Zigu UV6078, viscosity 30mPa·s) to obtain glass D2.

[0081] Performance test results:

[0082] Particle B02: After standing for 24 hours, the aggregation rate is 40% (no steric hindrance), the phase change temperature is 66℃ (the photothermal agent is not firmly bound and cannot effectively assist the phase change), and after being placed in a humid environment for 30 days, the indocyanine green loss rate is 32% (no chemical bonds are fixed).

[0083] Glass D2: Visible light transmittance 58% (agglomeration leads to light scattering), infrared transmittance 42% before phase transition, and infrared transmittance 35% after phase transition.

[0084] Comparative Example 3

[0085] Direct mixing reaction: 6g of VO2 nanoparticles (unaminated) were added to 100mL of indocyanine green buffer solution at pH=4 and reacted as in step 2 of Example 1. Since VO2 has no amino sites, the grafting rate of indocyanine green was only 8%, resulting in particles BO3.

[0086] Glass preparation: Same as step 3 in Example 1, to obtain glass D3.

[0087] Performance test results:

[0088] Particle B03: Phase transition temperature 67℃ (insufficient grafting amount, weak photothermal assistance), after being placed in a humid environment for 30 days, the phase transition temperature rises to 75℃, and the infrared blocking rate decreases by 25%.

[0089] Glass D3: Visible light transmittance 62% (partially agglomerated), infrared transmittance before phase transition 44%, infrared transmittance after phase transition 33%.

[0090] This invention successfully addresses three major defects of traditional VO2 materials through a two-step method of "amino-coated VO2 + indocyanine green chemical grafting". In Examples 1-6, the phase transition temperature of the composite particles was reduced to 32-38℃ (matching the ambient temperature), the performance change rate after 30 days in a humid environment was ≤2.8% (excellent stability), the visible light transmittance of the glass was 75%-82% (good light transmittance), and the infrared transmittance after the phase transition was ≤10% (strong heat insulation ability), proving that the technical solution can achieve a balance of "low temperature phase transition, high light transmittance, and high stability".

[0091] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0092] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for preparing indocyanine green photo-thermal heat insulation energy-saving composite particles, characterized in that, The preparation method comprises the following steps: (1) adding an amino silane coupling agent into an ethanol aqueous solution, dispersing the same at room temperature for 5-30 min to obtain a treatment liquid, then adding vanadium dioxide nanoparticles, and reacting at 60-70°C for 5-7 h, filtering the reaction liquid, repeatedly cleaning and filtering the same with an ethanol and water solution, and drying at 50-60°C to obtain amino-functionalized vanadium dioxide nanoparticles; (2) dissolving indocyanine green into an acidic buffer solution, then adding the amino-functionalized vanadium dioxide nanoparticles obtained in step (1), and reacting at 60-80°C for 8-12 h, then filtering the reaction liquid, repeatedly cleaning and filtering the same with deionized water, and drying at 50-60°C to obtain indocyanine green grafted vanadium dioxide nanoparticles; (3) finally, compounding the indocyanine green grafted vanadium dioxide nanoparticles obtained in step (3) with an acrylic resin precursor liquid, pouring the same between two glasses, and irradiating with ultraviolet light to obtain heat-insulating and energy-saving glass.

2. The method for preparing indocyanine green photo-thermal energy-saving composite particles according to claim 1, characterized in that, The amino silane coupling agent in step (1) is at least one of 3-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

3. The method for preparing indocyanine green photo-thermal energy-saving composite particles according to claim 1, characterized in that, The mass ratio of ethanol to water in the ethanol aqueous solution in step (1) is 4:1-8:1, the pH value is 3-6, and the mass fraction of the amino silane coupling agent is 1-3%.

4. The method for preparing indocyanine green photothermal insulating and energy-saving composite particles according to claim 1, characterized in that, The particle size of the vanadium dioxide nanoparticles in step (1) is 20-100 nm.

5. The method for preparing indocyanine green photothermal insulating and energy-saving composite particles according to claim 1, characterized in that, The mass ratio of the vanadium dioxide nanoparticles to the amino silane coupling agent in step (1) is 6:1-10:

1.

6. The method for preparing indocyanine green photothermal insulating and energy-saving composite particles according to claim 1, characterized in that, The indocyanine green in step (2) is at least one of indocyanine green and an indocyanine green derivative.

7. The method for preparing indocyanine green photothermal insulating and energy-saving composite particles according to claim 1, characterized in that, The mass ratio of the indocyanine green to the amino-functionalized vanadium dioxide nanoparticles in step (2) is 1:3-1:

5.

8. An indocyanine green light-heat energy-saving composite particle, characterized in that, The indocyanine green heat-insulating and energy-saving composite particles are prepared by the preparation method of any one of claims 1-7.