Composite glass structure and preparation method and application thereof

Abstract

The invention provides a composite glass structure and a preparation method and application thereof, and belongs to the field of energy-saving buildings. The composite glass structure comprises a substrate and a composite layer on one side of the substrate, wherein the composite layer comprises a substrate surface coating, a polymer middle coating and an outer coating which are sequentially overlapped, wherein the substrate surface coating is formed by a radiation function layer, an isolation layer and an illumination modulation layer. According to the preparation method, silver nanowires (AgNWs) and vanadium dioxide (VO2) are constructed on the surface of glass at the same time through a layer-by-layer self-assembly technology (LbL), and the preparation method comprises preparation of an AgNWs ethanol suspension and construction of a composite layer. The invention is suitable for the field of thermochromic intelligent windows, and is beneficial to solving the problems that the energy consumption of buildings is high, the existing thermochromic intelligent windows for adjusting near-infrared sunlight and intermediate infrared radiance are less, the preparation process is complicated, and the requirement on equipment is higher.

Description

Technical Field

[0001] The present invention relates to the field of energy-saving buildings, and in particular to a composite glass structure and a preparation method and application thereof. Background Art

[0002] Building energy consumption accounts for approximately 51% of total global electricity consumption and 33% of total greenhouse gas emissions. With the rapid development of contemporary society, this proportion is likely to rise further. In developed countries and regions such as the United States and the European Union, building energy consumption even accounts for 40% of total primary energy consumption. Windows, as one of the weakest links in building structure, contribute to energy losses of up to 50% of a building's total energy consumption.

[0003] The composite glass structure used in thermochromic smart windows has high light transmittance (T lum ) and sunlight modulation capability (ΔT sol ), along with its simple fabrication process and zero energy input, is considered a cost-effective energy-saving window technology. Furthermore, passive radiative cooling (RC) windows, which radiate heat into the cold of outer space via the mid-infrared band, offer an innovative solution for reducing building cooling energy consumption. The development of composite glass structures that combine solar modulation and mid-infrared radiative cooling, particularly integrated structures with dynamically adjustable spectra, could significantly reduce a building's year-round energy consumption.

[0004] Currently, there are very few reports on research on ultra-wideband spectral control smart windows. According to the patent with publication number CN119502480A, a near-infrared shielding thermochromic smart window and its preparation are described. The composite glass structure of the smart window consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 supersurface layer. Its preparation involves DC magnetron sputtering technology, high-energy pulsed magnetron sputtering technology and photolithography technology. It can be seen that the existing spectral selectivity control strategy is limited by complex structural design or expensive processing technology such as magnetron sputtering and photolithography technology. It has high requirements for equipment and is difficult to achieve large-area uniform film formation. There is a lack of precise control methods for the spatial distribution and quantity of multi-band functional materials. The development of high-performance composite glass structures still faces major challenges.

[0005] In summary, there is an urgent need to provide a preparation solution for a composite glass structure that can precisely control performance, has both solar light modulation and mid-infrared radiation cooling functions, and is feasible and low-cost. Summary of the Invention

[0006] The purpose of the present invention is to provide a composite glass structure and its preparation method and application. The composite glass structure is suitable for the field of thermochromic smart windows. AgNWs and VO2 can be simultaneously constructed on the glass surface through layer-by-layer self-assembly technology, which helps to solve the problems of high building energy consumption, the lack of existing thermochromic smart windows that adjust near-infrared sunlight and mid-infrared emissivity, and their complex preparation process and high equipment requirements.

[0007] In a first aspect, the present invention provides a composite glass structure, characterized by comprising a substrate and a composite layer formed on one side of the substrate; the composite layer comprises a substrate surface coating, a polymer intermediate coating, and an outer coating, which are sequentially stacked and composed of a radiation functional layer, an isolation layer, and a light modulation layer;

[0008] The substrate surface coating is composed of an isolation layer and / or a radiation functional layer; the polymer intermediate coating is composed of an isolation layer; and the outer coating is composed of an isolation layer and a light modulation layer.

[0009] Optionally, the substrate includes at least one of glass, a PDMS flexible film and a PET film.

[0010] Optionally, the composite layer can adjust the thickness and distance between the substrate surface coating, the polymer intermediate coating, the outer coating and each coating by repeatedly stacking the radiation functional layer, the isolation layer and the light modulation layer.

[0011] Optionally, the radiation functional layer is an ITO layer or an AgNWs layer; the isolation layer includes PEI, PDDA and PAA, wherein PDDA can be replaced by PAH; and the light modulation layer is a VO2 nanoparticle layer or a W-doped VO2 layer.

[0012] Optionally, the isolation layers in the polymer intermediate coating and the outer coating are PDDA and PAA or PAH and PAA, and the isolation layers on one side or both sides of the light modulation layer in the outer coating are PDDA or PAH.

[0013] In a second aspect, the present invention provides a method for preparing any of the above composite glass structures, wherein the composite glass structure is constructed using a layer-by-layer self-assembly technique, comprising the following steps:

[0014] 1. Preparation of AgNWs ethanol suspension:

[0015] PVP was stirred and dissolved in glycerol to obtain a PVP-containing glycerol solution, and after cooling, AgNO3 particles and a NaCl mixed solution were sequentially added to obtain a reactant system. The reactant system was heated and cooled, and the precipitate was collected and rinsed and centrifuged, and then dispersed in ethanol to obtain an AgNWs ethanol suspension.

[0016] 2. Build the base surface coating:

[0017] The cleaned substrate is immersed in a PEI aqueous solution, taken out, rinsed, blown dry, and then immersed in an AgNWs ethanol suspension at a specific speed. After slowly moving up and ethanol evaporation, a single layer of PEI / AgNWs is obtained. By repeatedly depositing PEI and AgNWs m times, a substrate surface coating composed of m layers of PEI and AgNWs (PEI / AgNWs) can be obtained. m ;

[0018] 3. Forming polymer intermediate coating:

[0019] Will be loaded with (PEI / AgNWs) m The substrate is immersed in a PDDA aqueous solution, rinsed, and then immersed in a PAA aqueous solution. The substrate is taken out and rinsed to obtain a single-layer PDDA / PAA coating. By repeating the operation o times, a polymer intermediate coating (PDDA / PAA) composed of o layers of PDDA and PAA is obtained. o ;

[0020] 4. Build the outer coating:

[0021] Will be loaded with (PEI / AgNWs) m (PDDA / PAA) o The substrate is immersed in PDDA or PAH solution, rinsed and then immersed in PAA solution, rinsed and immersed in PDDA aqueous solution again, taken out and rinsed and immersed in VO2 ethanol suspension at a specific speed, and slowly moved up to obtain a single layer of PDDA / PAA / PDDA / VO2 coating after ethanol volatilization. Repeat n times to obtain an outer coating composed of n layers of PDDA, PAA, PDDA and VO2 (PDDA / PAA / PDDA / VO2) n ;

[0022] Wherein, m, o, and n are independently any integer greater than or equal to 1, the PDDA aqueous solution can be replaced by a PAH aqueous solution, and the VO2 ethanol suspension can be replaced by a W-doped VO2 ethanol suspension.

[0023] Optionally, the mass volume concentration of PVP and glycerol in the PVP-containing glycerol solution in step one is 2.8%-3.2%, the NaCl mixed solution is a mixed solution of NaCl particles, deionized water and glycerol, the mass ratio of the NaCl particles, deionized water and glycerol is 65-95:600:15600, the mass ratio of AgNO3 and NaCl in the reactant system is 90-105:4, and the heating and cooling treatment is heating to 200°C-230°C, cooling to 95°C-120°C, adding deionized water, and then cooling to room temperature.

[0024] Optionally, in step 2, the glass substrate is cleaned by using a plasma cleaning machine for 10-20 minutes, the concentration of the PEI aqueous solution is 4-7 mg / mL, and the immersion time is 8-12 minutes.

[0025] Optionally, the concentration of the AgNWs ethanol suspension in step 1 and / or step 2 is 4-8 mg / mL; the concentration of the PDDA aqueous solution and / or PAA aqueous solution in step 3 and / or step 4 is 0.1-2 mg / mL, and the immersion time is 4-7 min; the specific speed in step 2 and / or step 4 is 95-110 mm / min; the concentration of the VO2 ethanol suspension in step 4 is 8-12 mg / mL.

[0026] In a third aspect, the present invention also provides the use of a composite glass structure prepared by any of the above-described methods in a thermochromic smart window. This thermochromic smart window can precisely control its performance, simultaneously utilizing both near-infrared solar modulation and mid-infrared radiative cooling.

[0027] The beneficial effects of the present invention include:

[0028] (1) The composite glass structure provided by the present invention can adjust the thickness and distance between the substrate surface coating, polymer intermediate coating, outer coating and each coating by repeatedly stacking the radiation functional layer, isolation layer and light modulation layer, thereby achieving precise control of the spatial distribution and quantity of functional materials.

[0029] (2) The preparation method based on layer-by-layer self-assembly technology provided by the present invention utilizes LbL technology to replace the traditional magnetron sputtering process, and can complete multilayer film assembly at room temperature and pressure, reducing equipment costs. In addition, the construction of each coating layer relies on the electrostatic interaction between polyelectrolytes. The specific isolation layer not only enhances the interlayer bonding strength but also promotes uniform coverage of nanoparticles, enhancing stability. The preparation process is simple and is generally carried out in water or ethanol, which is environmentally friendly and suitable for industrial mass production.

[0030] (3) The present invention is applied to thermochromic smart windows. Through the synergistic effect of AgNWs and VO2, dual-band management of near-infrared sunlight and mid-infrared emissivity is achieved, which is highly efficient and energy-saving. In addition, the regulation effect can be controlled by changing the number of AgNWs layers, VO2 layers, and isolation layers to achieve optimal energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1Schematic diagram of the structure of the composite glass structure of the present invention when m, o, and n are all 1, and the structure is glass / (PEI / AgNWs) / (PDDA / PAA) / (PDDA / PAA / PDDA / VO2). In the figure, 1 is glass, 2 is PEI layer, 3 is AgNWs layer, 4 is PDDA layer, 5 is PAA layer, and 6 is VO2 particle layer. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs.

[0033] An embodiment of the present invention provides a composite glass structure, comprising a substrate and a composite layer formed on one side of the substrate; the composite layer comprises a substrate surface coating, a polymer intermediate coating, and an outer coating, which are sequentially stacked based on a radiation functional layer, an isolation layer, and a light modulation layer;

[0034] The substrate surface coating is composed of an isolation layer and / or a radiation functional layer; the polymer intermediate coating is composed of an isolation layer; and the outer coating is composed of an isolation layer and a light modulation layer.

[0035] In some embodiments, the substrate includes at least one of glass, a PDMS flexible film, and a PET film.

[0036] Specifically, the composite layer can adjust the thickness and distance between the substrate surface coating, the polymer intermediate coating, the outer coating and each coating by repeatedly stacking the radiation functional layer, the isolation layer and the light modulation layer.

[0037] In some embodiments, the radiation functional layer is an ITO layer or an AgNWs layer, the isolation layer includes PEI, PDDA and PAA, or PDDA is replaced by PAH, and the light modulation layer is a VO2 nanoparticle layer or a W-doped VO2 layer.

[0038] In some embodiments, the substrate surface coating includes a PEI barrier layer, the polymer intermediate coating and outer coating include PDDA and PAA or PAH and PAA, and the outer coating includes PDDA or PAH as the barrier layer on one or both sides of the light modulation layer. In practice, the PEI barrier layer, combined with the AgNW radiation-functional layer, possesses a positive charge and high density. This not only strengthens the bond with the other layers through electrostatic interactions but also effectively disperses the AgNWs, enhancing stability.

[0039] An embodiment of the present invention provides a method for preparing any of the above-mentioned composite glass structures, wherein the composite glass structure is constructed using a layer-by-layer self-assembly technique, comprising the following steps:

[0040] 1. Preparation of AgNWs ethanol suspension:

[0041] PVP was stirred and dissolved in glycerol to obtain a PVP-containing glycerol solution, and after cooling, AgNO3 particles and a NaCl mixed solution were sequentially added to obtain a reactant system. The reactant system was heated and cooled, and the precipitate was collected and rinsed and centrifuged, and then dispersed in ethanol to obtain an AgNWs ethanol suspension.

[0042] 2. Build the base surface coating:

[0043] The cleaned substrate is immersed in a PEI aqueous solution, taken out, rinsed, blown dry, and then immersed in an AgNWs ethanol suspension at a specific speed. After slowly moving up and ethanol evaporation, a single layer of PEI / AgNWs is obtained. By repeatedly depositing PEI and AgNWs m times, a substrate surface coating composed of m layers of PEI and AgNWs (PEI / AgNWs) can be obtained. m ;

[0044] 3. Forming polymer intermediate coating:

[0045] Will be loaded with (PEI / AgNWs) m The substrate is immersed in a PDDA aqueous solution, rinsed, and then immersed in a PAA aqueous solution. The substrate is taken out and rinsed to obtain a single-layer PDDA / PAA coating. By repeating the operation o times, a polymer intermediate coating (PDDA / PAA) composed of o layers of PDDA and PAA is obtained. o ;

[0046] 4. Build the outer coating:

[0047] Will be loaded with (PEI / AgNWs) m (PDDA / PAA) oThe substrate is immersed in PDDA or PAH solution, rinsed and then immersed in PAA solution, rinsed and immersed in PDDA aqueous solution again, taken out and rinsed and immersed in VO2 ethanol suspension at a specific speed, and slowly moved up to obtain a single layer of PDDA / PAA / PDDA / VO2 coating after ethanol volatilization. Repeat n times to obtain an outer coating composed of n layers of PDDA, PAA, PDDA and VO2 (PDDA / PAA / PDDA / VO2) n ;

[0048] Here, m, o, and n are independently any integer greater than or equal to 1. The PDDA aqueous solution can be replaced with a PAH aqueous solution, and the VO2 ethanol suspension can be replaced with a W-doped VO2 ethanol suspension. In practice, when pure VO2 is used as the light modulation layer, its phase transition temperature is 68°C, effectively modulating sunlight at this temperature. When W-doped VO2 is used, the phase transition temperature is closer to room temperature, 36°C.

[0049] In some embodiments, the mass volume concentration of PVP and glycerol in the PVP-containing glycerol solution in step one is 2.8%-3.2%, the NaCl mixed solution is a mixed solution of NaCl particles, deionized water and glycerol, the mass ratio of NaCl particles, deionized water and glycerol is 65-95:600:15600, the mass ratio of AgNO3 and NaCl in the reactant system is 90-105:4, and the heating and cooling treatment is heating to 200°C-230°C, cooling to 95°C-120°C, adding deionized water, and then cooling to room temperature.

[0050] Specifically, the glass substrate is cleaned in step 2 by using a plasma cleaning machine for 10-20 minutes, the concentration of the PEI aqueous solution is 4-7 mg / mL, and the immersion time is 8-12 minutes.

[0051] Specifically, the concentration of the AgNWs ethanol suspension in step one and / or step two is 4-8 mg / mL; the concentration of the PDDA aqueous solution and / or PAA aqueous solution in step three and / or step four is 0.1-2 mg / mL, and the immersion time is 4-7 min; the specific speed in step two and / or step four is 95-110 mm / min; the concentration of the VO2 ethanol suspension in step four is 8-12 mg / mL.

[0052] In a third aspect, the present invention further provides the use of a composite glass structure prepared by any of the above items and / or any of the methods in a thermochromic smart window.

[0053] The AgNWs ethanol suspensions used in the following examples were prepared by the following steps: 7 g of polyvinylpyrrolidone (PVP) was dissolved in 230 mL of glycerol at 100°C with stirring. After cooling to room temperature, 1.9 g of AgNO₃ was added to the system. A mixture containing 80 mg of NaCl, 0.6 mL of deionized water, and 12 mL of glycerol was also added. The system was heated from room temperature to 210°C, then cooled to 110°C. 240 mL of deionized water was added, cooled to room temperature, and the entire system was allowed to stand for one week. The precipitate at the bottom of the round-bottom flask was slowly collected, rinsed with ethanol, and centrifuged three times (6000 rpm). Finally, it was dispersed in ethanol to prepare a 7 mg / mL AgNWs ethanol suspension.

[0054] Example 1

[0055] This embodiment provides glass / (PEI / AgNWs) m / (PDDA / PAA) o / (PDDA / PAA / PDDA / VO2) n Specific preparation steps of the composite structure:

[0056] First, the glass slide was treated with a plasma cleaner for 15 minutes, immersed in a polyethyleneimine (PEI) solution for 10 minutes, rinsed with deionized water for 3 minutes (1 minute each time), and blown dry. The glass slide loaded with PEI was immersed in a 7mg / mL AgNWs ethanol suspension at a speed of 100mm / min and left to stand for 2 seconds. It was then moved up at 100mm / min. After the ethanol evaporated, a single layer of AgNWs was obtained. The glass slide loaded with AgNWs was immersed in the PEI solution again and rinsed with deionized water to obtain a second layer of PEI. The second layer of AgNWs can be obtained by the method of depositing the first layer of AgNWs. By repeatedly depositing PEI and AgNWs m times, a substrate surface coating (PEI / AgNWs) of m layers can be obtained. m ;

[0057] 2. Loading (PEI / AgNWs) m The glass slide was immersed in a polydiallyldimethylammonium chloride (PDDA) aqueous solution (2 mg / mL) for 5 min and rinsed with deionized water three times (1 min each time); then immersed in a polyacrylic acid (PAA) aqueous solution (2 mg / mL) for 5 min and rinsed with deionized water three times (1 min each time); after o cycles, o layers of PDDA and PAA-composed polymer intermediate coating (PDDA / PAA) were obtained to obtain glass / (PEI / AgNWs) m / (PDDA / PAA) o structure.

[0058] 3. Loading (PEI / AgNWs) m / (PDDA / PAA) o The glass sheets were covered with PDDA / PAA / PDDA films by layer-by-layer self-assembly to obtain the following structure: glass / (PEI / AgNWs) m / (PDDA / PAA) o / PDDA / PAA / PDDA, and then immersed in VO2 ethanol suspension (10 mg / mL) at a specific speed (100 mm / min) and allowed to stand for 2 seconds, and then slowly moved up at the same speed. After the ethanol evaporated, the following was obtained: glass / (PEI / AgNWs) m / (PDDA / PAA) o / PDDA / PAA / PDDA / VO2, repeat the above steps n times to obtain glass / (PEI / AgNWs) m / (PDDA / PAA) o / (PDDA / PAA / PDDA / VO2) n .

[0059] When m=0, the structure is glass / (PDDA / PAA) o / (PDDA / PAA / PDDA / VO2) n , o and n can be any integer greater than or equal to 1, and the structure does not have mid-infrared emissivity ε MIR Modulation capability;

[0060] Bottom layer (PEI / AgNWs) m Mid-infrared emissivity of low-emissivity coatings (ε MIR ) also decreases with the increase of m value. When m≥3, the emissivity (ε MIR )≤0.1. When o=39 and n=5 are fixed, the value of m changes to 3, 4 and 5, and the visible light transmittance (T lum ) are 25.9%, 18.6% and 14.4% respectively, and decrease with the increase of m value; at the same time, the solar light modulation capacity (ΔT sol ) also decreases as the value of m increases. When the value of m increases from 3 to 5, ΔT sol From 9.02% to 5.26%. Moreover, this structure has different emissivity at high and low temperatures. For example, when m = 3, ε at 25 ° C MIR Close to 0.4, ε at 90℃ MIR Increased to 0.67, Δε MIR (ε MIR High temperature-ε MIR Low temperature) decreases with the increase of m value, where high temperature is above 68℃ and low temperature is below 68℃.

[0061] Preferably, the composite glass structure prepared by the above method has an optimal visible light transmittance of 26%, a solar light modulation capability of 9.1%, and a mid-infrared emissivity modulation capability of 0.3. Glass / (PEI / AgNWs)3 / (PDDA / PAA) is selected for use in thermochromic smart windows. 39 / (PDDA / PAA / PDDA / VO2)5.

[0062] Example 2

[0063] The difference between Example 2 and Example 1 lies in the number of layers of the polymer intermediate coating (PDDA / PAA) and the concentrations of PDDA and PAA. The specific structure is glass / (PEI / AgNWs)3 / (PDDA / PAA) o / (PDDA / PAA / PDDA / VO2)5, to explore the effect of the isolation layer on the optical properties.

[0064] When m=3 and n=5, the change of o value (o=31,33,35,37,39,41) found that the transmittance and reflectance of the energy-saving window at 250nm-2500nm did not change much, mainly because (PDDA / PAA) o The film has a high transmittance.

[0065] The concentration of PAA was fixed at 2 mg / mL, and the concentration of PDDA was varied: 0.125 mg / mL, 0.25 mg / mL, 2 mg / mL to adjust (PDDA / PAA) o The components in the film, among which, in the wavelength range of 8-14μm, PAA has a very low absorption rate, while PDDA has a higher absorption rate. When the concentration of PDDA is 0.25mg / mL, the absorption rate of ε MIR Has the best modulation effect, Δε MIR Close to 0.3; when the PDDA concentration is 2 mg / mL, PDDA has strong absorption at 8-14 μm, which has a great influence on ε MIR The modulation effect was inhibited; when the PDDA concentration was 0.125 mg / mL, it was not conducive to the construction of layer-by-layer self-assembled films because the concentration was too low.

[0066] Example 3

[0067] The difference between this embodiment 3 and embodiment 1 is that the glass containing ITO material is directly used to cover the polymer intermediate coating and the outer coating. The specific structure is ITO / (PDDA / PAA) 28 / (PDDA / PAA / PDDA / VO2) n , to explore the effect of the (PDDA / PAA / PDDA / VO2) outer coating on the optical properties.

[0068] Specifically, fix o=28, change the value of n from 4 to 6, and when n is 5, there is a MIR Has the best modulation effect.

[0069] Preferably, when applied to thermochromic smart windows, with n=5 and o=31, ITO / (PDDA / PAA) 31 / (PDDA / PAA / PDDA / VO2)5 has the best optical properties: T lum 41%,ΔT sol is 10.1%, Δε MIR is 0.4.

[0070] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. A composite glass structure, characterized in that: It includes a substrate and a composite layer formed on one side of the substrate; the composite layer includes a substrate surface coating, a polymer intermediate coating and an outer coating formed by sequentially stacking a radiation functional layer, an isolation layer and a light modulation layer; The substrate surface coating is composed of an isolation layer and / or a radiation functional layer; the polymer intermediate coating is composed of an isolation layer; and the outer coating is composed of an isolation layer and a light modulation layer.

2. The composite glass structure according to claim 1, characterized in that The substrate includes at least one of glass, a PDMS flexible film and a PET film.

3. The composite glass structure according to claim 1, wherein: The composite layer can adjust the thickness or distance between the substrate surface coating, the polymer intermediate coating, the outer coating and each coating by repeatedly stacking the radiation functional layer, the isolation layer and the light modulation layer.

4. The composite glass structure according to claim 1, wherein: The radiation functional layer is an ITO layer or an AgNWs layer; the isolation layer includes PEI, PDDA and PAA, wherein PDDA can be replaced by PAH; the light modulation layer is a VO2 nanoparticle layer or a W-doped VO2 layer.

5. The composite glass structure according to claim 1, wherein: The isolation layer in the substrate surface coating is PEI; the isolation layers in the polymer intermediate coating and the outer coating are PDDA and PAA or PAH and PAA; the isolation layers on one side or both sides of the light modulation layer in the outer coating are PDDA or PAH.

6. A method for preparing a composite glass structure according to any one of claims 1 to 5, characterized in that: The composite glass structure is constructed using layer-by-layer self-assembly technology, comprising the following steps:

1. Preparation of AgNWs ethanol suspension: PVP was stirred and dissolved in glycerol to obtain a PVP-containing glycerol solution, and after cooling, AgNO3 particles and a NaCl mixed solution were sequentially added to obtain a reactant system. The reactant system was heated and cooled, and the precipitate was collected and rinsed and centrifuged, and then dispersed in ethanol to obtain an AgNWs ethanol suspension.

2. Build the base surface coating: The cleaned substrate is immersed in a PEI aqueous solution, taken out, rinsed, blown dry, and then immersed in an AgNWs ethanol suspension at a specific speed. After slowly moving up and ethanol evaporation, a single layer of PEI / AgNWs is obtained. By repeatedly depositing PEI and AgNWs m times, a substrate surface coating composed of m layers of PEI and AgNWs (PEI / AgNWs) can be obtained. m ; 3. Forming polymer intermediate coating: Will be loaded with (PEI / AgNWs) m The substrate is immersed in a PDDA aqueous solution, rinsed, and then immersed in a PAA aqueous solution. The substrate is taken out and rinsed to obtain a single-layer PDDA / PAA coating. By repeating the operation o times, a polymer intermediate coating (PDDA / PAA) composed of o layers of PDDA and PAA is obtained. o ; 4. Build the outer coating: Will be loaded with (PEI / AgNWs) m (PDDA / PAA) o The substrate is immersed in PDDA or PAH solution, rinsed and then immersed in PAA solution, rinsed and immersed in PDDA aqueous solution again, taken out and rinsed and immersed in VO2 ethanol suspension at a specific speed, and slowly moved up to obtain a single layer of PDDA / PAA / PDDA / VO2 coating after ethanol volatilization. Repeat n times to obtain an outer coating composed of n layers of PDDA, PAA, PDDA and VO2 (PDDA / PAA / PDDA / VO2) n ; Wherein, m, o, and n are independently any integer greater than or equal to 1, the PDDA aqueous solution can be replaced by a PAH aqueous solution, and the VO2 ethanol suspension can be replaced by a W-doped VO2 ethanol suspension.

7. The method for preparing a composite glass structure according to claim 6, wherein: The mass volume concentration of PVP and glycerol in the PVP-containing glycerol solution in step 1 is 2.8%-3.2%, the NaCl mixed solution is a mixed solution of NaCl particles, deionized water and glycerol, the mass ratio of the NaCl particles, deionized water and glycerol is 65-95:600:15600, the mass ratio of AgNO3 and NaCl in the reactant system is 90-105:4, and the heating and cooling treatment is heating to 200°C-230°C, cooling to 95°C-120°C, adding deionized water, and then cooling to room temperature.

8. The method for preparing a composite glass structure according to claim 6, wherein: The concentration of the PEI aqueous solution in step 2 is 4-7 mg / mL, and the immersion time is 8-12 minutes.

9. The method for preparing a composite glass structure according to claim 6, wherein: The concentration of the AgNWs ethanol suspension in step 1 and / or step 2 is 4-8 mg / mL; the concentration of the PDDA aqueous solution and / or PAA aqueous solution in step 3 and / or step 4 is 0.1-2 mg / mL, and the immersion time is 4-7 min; the specific speed in step 2 and / or step 4 is 95-110 mm / min; the concentration of the VO2 ethanol suspension in step 4 is 8-12 mg / mL.

10. Use of the composite glass structure according to any one of claims 1 to 5 and / or the composite glass structure prepared by the method according to any one of claims 6 to 9 in a thermochromic smart window.

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