A preparation method of a photoluminescence, reinforced, heat preservation and heat insulation nanocomposite coating

Abstract

The application is a preparation method of a photoluminescence, reinforced, heat preservation and heat insulation nano composite coating. The method uses triethoxysilane as raw material, and prepares multi-level structure fluorescent nanoparticles with defect centers (=Si(O2), =Si:) through a mild (about 70 DEG C) sol-gel method, and then the nanoparticles are compounded into a coating matrix, and a solid and durable fluorescent coating is developed by using the defect-induced luminescence technology; in addition, the multi-level cavity structure of the nanoparticles can encapsulate more air, so as to provide excellent heat preservation and heat insulation performance for the coating. The obtained nano composite coating with photoluminescence, excellent mechanical performance and heat preservation and heat insulation expands the commercial application field of the fluorescent coating.

Description

Technical Field

[0001] This invention relates to the field of multifunctional coating preparation technology, specifically to a method for preparing a photoluminescent, enhanced, and thermally insulating nanocomposite environmentally friendly coating. Background Technology

[0002] Fluorescent coatings, capable of fluorescing under ultraviolet or visible light, have been widely applied in various fields. However, most existing fluorescent coatings exhibit limitations such as limited functionality. The presence of fluorescent substances inevitably affects the performance of the coating film, including poor water resistance, poor weather resistance, and low mechanical strength. Furthermore, because fluorescent substances are typically small molecules, they are prone to leaching during use and can undergo aggregation quenching, resulting in the loss of fluorescence. One of the most common modification strategies is the addition of luminescent nanoparticles, which, compared to traditional organic fluorophores, exhibit better biocompatibility, lower toxicity, and greater chemical and physical stability.

[0003] Compared with other fluorescent material preparation methods, the nanoparticle composite method has great advantages in material design and environmental protection. However, the current preparation process of luminescent nanoparticles is relatively complicated and has a single function. Lee used nanoparticles coated with fluorescent substances to modify epoxy coatings. Scratches on the coating surface will expose the fluorescent substances and generate strong fluorescence, which can be used for crack detection (Appl.Surf.Sci,2018,434:1327-1335). Nair synthesized fluorescent silica nanoparticles and prepared photoluminescent inks using ethanol as a solvent for applications such as information encryption (ACS omega,2019,4(2):2577-2583). However, although the nanoparticles prepared above endow the matrix with photoluminescent properties, their preparation methods are relatively complicated and do not bring other advantageous properties to the matrix. By directly integrating photoluminescence and hollow structure into silicon-based nanoparticles themselves, the robustness of nanocomposite materials can be enhanced, and the composite material system can be endowed with photoluminescence and thermal insulation capabilities.

[0004] In summary, the current methods for preparing hollow nanoparticles are cumbersome and have relatively limited functions. Furthermore, the potential of defect-induced emission in fluorescent coatings has been overlooked. Therefore, it is crucial to design a novel, simple, and economical method for preparing anisotropic hollow nanoparticles and to study their multifunctionality in coatings. Summary of the Invention

[0005] The purpose of this invention is to address the limitations of current technologies by providing a method for preparing a photoluminescent, enhanced, and thermally insulating nanocomposite coating. This method uses triethoxysilane as a raw material and prepares multi-level fluorescent nanoparticles with defect centers (=Si(O2), =Si:) through a mild sol-gel method at around 70°C. These nanoparticles are then composited into a coating matrix, and a robust and durable fluorescent coating is developed using defect-induced emission technology. Furthermore, the multi-level cavity structure of the particles can encapsulate more air, providing the coating with excellent thermal insulation properties. The nanocomposite coating obtained by this invention, possessing photoluminescence, excellent mechanical properties, and thermal insulation, expands the commercial application fields of fluorescent coatings.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a photoluminescent, enhanced, and thermally insulating nanocomposite coating, comprising the following steps:

[0008] The first step involves mixing styrene, compound A, and compound B in a reactor until homogeneous. The mixture is then added dropwise to a hydrochloric acid aqueous solution with a pH of 3-4 over 10-30 minutes. After reacting for 1-2 hours, ammonia is added to adjust the pH to 9-11. The reaction continues for 0.5-1 hour, followed by heating to 60-80°C under a nitrogen atmosphere. An initiator solution is then added dropwise, and the reaction continues for 2-4 hours to obtain multi-level structured particles. These particles are then calcined in a muffle furnace at 300-500°C for 3-7 hours to obtain multi-level structured hollow particles (SOB).

[0009] The mass ratio of styrene to compound A is 1:0.25–4; the mass ratio of the total mass of styrene and compound A to compound B is 1:0.25–4; the mass of the initiator is 0.3%–1.0% of the total mass of styrene and compound A; and the concentration of ammonia is 28%.

[0010] The compound A is one or more acrylates, specifically n-butyl acrylate, p-tert-butylstyrene, tert-butyl acrylate or octadecyl acrylate;

[0011] The compound B is one or more organosiloxanes, specifically methyltriethoxysilane, phenyltriethoxysilane, ethyltriethoxysilane or tridecafluorooctyltriethoxysilane;

[0012] The initiator is one or more of the water-soluble initiators potassium persulfate (KPS), ammonium persulfate (APS), azobisisobutyramidine hydrochloride (AIBA), and azobisisobutyramidine hydrochloride (AIBI);

[0013] The second step involves adding the calcined multi-level hollow particles to the matrix latex under magnetic stirring at 800–1200 rpm to obtain a stable matrix / SOB dispersion.

[0014] The mass ratio of SOB particles to matrix emulsion is 1:50 to 200.

[0015] The base latex is a type of water-based coating latex, specifically water-based styrene-acrylic emulsion (SA), polyurethane emulsion, or polyvinyl acetate emulsion; with a concentration of 10% to 20%.

[0016] The third step is to coat the matrix / SOB dispersion obtained in the second step onto the substrate and dry it at room temperature for 12 to 36 hours to obtain the matrix / SOB composite coating.

[0017] Among them, each 5×5cm 2 A dispersion of 10-20g is coated onto a substrate. The substrate is specifically a glass or polypropylene membrane.

[0018] The essential features of this invention are:

[0019] This invention utilizes compound B, such as methyltriethoxysilane (MTES), as a raw material. This substance both forms particles and serves as the initial source of fluorescence (i.e., compound B can hydrolyze to generate amphiphilic silane oligomers (ethoxy groups can hydrolyze to generate hydroxyl groups), acting as an emulsifier to deemulsify monomers, condensing under alkaline conditions to form particles. During condensation, oxygen vacancy defect pairs =Si(O2) and =Si: are formed, and these defects induce particle luminescence). A mild method is developed to prepare hierarchical hollow silicon-based particles with defect sites. By incorporating these particles into a coating matrix, the mechanical properties of the coating are effectively enhanced, and photoluminescence and thermal insulation properties are imparted. This invention, while achieving photoluminescence and thermal insulation functions, also improves the mechanical strength, water resistance, abrasion resistance, and weather resistance of the coating, thus providing potential for expanding the commercial application of polymer fluorescent coatings.

[0020] The beneficial effects of this invention are as follows:

[0021] Most existing fluorescent coatings exhibit unstable fluorescence and limited functionality. Currently, there are few reports on endowing composite coatings with photoluminescence properties using nanoparticles with defect sites. This invention prepares a coating with water resistance and excellent mechanical strength (Young's modulus reaches 22.47 MPa). Furthermore, this composite coating, while possessing excellent mechanical properties, also exhibits thermal insulation properties and superior photoluminescence capabilities, demonstrating great potential for multifunctional coating applications. Attached Figure Description

[0022] Figure 1SOB prepared in Examples 1-4 x The FT-IR spectrum; where, Figure 1 a is the FT-IR spectrum before calcination. Figure 1 b is the FT-IR spectrum after calcination;

[0023] Figure 2 SOB before calcination prepared in Examples 1-4 x SEM images of particles;

[0024] Figure 3 Calcinated SOB prepared in Examples 1-4 x TEM images of particles;

[0025] Figure 4 Calcinated SOB prepared in Examples 1-4 x Fluorescence spectrum of the particles;

[0026] Figure 5 The SA coatings and SA / SOB obtained in Examples 1-4 and Comparative Example 1. x Stress-strain curves of the composite coating;

[0027] Figure 6 The SA coatings and SA / SOB obtained in Examples 1-4 and Comparative Example 1. x The water-wetting state of the composite coating. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings. The following embodiments are illustrative and not limiting, and should not be used to limit the scope of protection of the present invention.

[0029] Example 1.

[0030] The synthesis of a nanocomposite coating involves the following specific steps:

[0031] The first step involved ultrasonically dispersing 0.96 g styrene, 0.24 g butyl acrylate, and 1.2 g methyltriethoxysilane at 40 Hz for 5 min until homogeneous. The mixture was then added dropwise to a hydrochloric acid aqueous solution with a pH of 3.5 at an injection rate of 0.4 g / min. After stirring at 250 rpm at room temperature for 1 h, ammonia (28%) was added to adjust the pH to 10. Stirring continued at 250 rpm for 50 min at room temperature. Air was then purged through the mixture with N2, and the mixture was heated to 70 °C. 0.0072 g KPS dissolved in 5 mL of distilled water was added dropwise to the solution. The stirring speed was reduced to 150 rpm, and the reaction proceeded for 2 h. After freeze-drying, multi-level structured particle powder was obtained. The particles were then calcined in a muffle furnace at 500 °C for 5 h to obtain multi-level structured hollow particles (SOB1).

[0032] In the second step, 0.1 g of SOB1 powder was added to 10 g of SA emulsion (15 wt%) under magnetic stirring at 1000 rpm to obtain a stable SA / SOB1 dispersion; the 10 g SA / SOB1 dispersion was then coated onto a 5×5 cm plate. 2 SA / SOB1 composite coating was obtained by drying on release paper (polypropylene film) at room temperature for 24 hours;

[0033] Fourier transform infrared (FTIR) spectroscopy was performed on SOB1 particles before and after calcination using a German Tensor-27 spectrometer. The results are as follows: Figure 1 As shown. Particles at 1126, 1037, and 437 cm⁻¹. -1 The area shows stretching and bending vibrational bands of Si-O-Si(Si-OH) bonds at 1270 and 777 cm⁻¹. -1 The text describes the stretching and bending vibrational bands of the Si-CH3 bonds. Furthermore, these bands are observed at 1600, 1490, 1494, 1450, and 698 cm⁻¹. -1 The characteristic band of the benzene ring is displayed at 1730 cm⁻¹, and at 1730 cm⁻¹... -1 The infrared peaks of the polymer, including the C=O bond stretching vibration band, were observed. The polymer's infrared peaks disappeared after calcination. This indicates that the nanoparticles were successfully prepared and the polymer template was successfully removed after calcination.

[0034] The morphology of the calcined particles was observed using a Japanese 7610F scanning electron microscope and an American Talos F200S transmission electron microscope. The results are as follows: Figure 2 a and Figure 3 As shown in figure a, multi-level silicon-based particles were successfully prepared, and cavities were formed inside after calcination.

[0035] The fluorescence intensity of the particle solution was measured using a British FSP920 fluorescence spectrometer, and the results are as follows: Figure 4 As shown in curve SOB1, the particles exhibit the highest intensity fluorescence emission peak at 420 nm, with a fluorescence intensity of 1 × 10⁻⁶. 4 This indicates that the prepared particles possess photoluminescence properties.

[0036] In addition, the mechanical properties of the coating were determined using a CMT-6104 universal testing machine. The tensile curve of the SA / SOB1 composite coating is shown below. Figure 5 The curves are shown in Table 1 for specific data. The tensile strength, elongation at break, and Young's modulus of the SA / SOB1 composite coating are 6.42 MPa, 1755.07%, and 22.47 MPa, respectively. Static water contact angle tests were performed on the film using the seated drop method with a DSA30S optical contact angle meter. Figure 6It can be seen that the static water contact angle of the film is 112°, indicating that the coating exhibits hydrophobicity. The thermal conductivity of the coating was measured using a TC 3000 thermal constant analyzer.

[0037] As shown in Table 3, the thermal conductivity of the SA / SOB1 composite coating is 0.1021 W·m. -1 ·K -1 The thermal conductivity of the film is significantly lower than that of the original SA film, indicating that it has excellent thermal insulation performance.

[0038] Example 2.

[0039] The synthesis of a nanocomposite coating involves the following specific steps:

[0040] In the first step, 0.64 g of styrene, 0.16 g of butyl acrylate, and 1.6 g of methyltriethoxysilane were ultrasonically dispersed at 40 Hz for 5 min and mixed thoroughly. The mixture was then added dropwise to a hydrochloric acid aqueous solution with a pH of 3.5 at an injection rate of 0.4 g / min. After stirring at 250 rpm at room temperature for 1 h, ammonia was added to adjust the pH of the system to 10. Stirring was continued at 250 rpm for 50 min at room temperature. Then, N2 was introduced to remove air, and the mixture was heated to 70 °C. 0.0048 g of KPS dissolved in 5 mL of distilled water was added dropwise to the mixture. The stirring speed was reduced by 150 rpm, and the reaction was carried out for 2 h to obtain multi-level structured particles. The particles were calcined in a muffle furnace at 500 °C for 5 h to obtain multi-level structured hollow particles (SOB2).

[0041] The second step involves adding 0.1g of SOB2 powder to 10g of SA emulsion under magnetic stirring at 1000rpm to obtain a stable SA / SOB2 dispersion; coating 10g of SA / SOB2 dispersion onto release paper and drying at room temperature for 24h to obtain an SA / SOB2 composite coating.

[0042] Fourier transform infrared (FTIR) spectroscopy was performed on SOB2 particles before and after calcination using a German Tensor-27 spectrometer. The results are as follows: Figure 1 As shown. Particles at 1126, 1037, and 437 cm⁻¹. -1 The area shows stretching and bending vibrational bands of Si-O-Si(Si-OH) bonds at 1270 and 777 cm⁻¹. -1 The text describes the stretching and bending vibrational bands of the Si-CH3 bonds. Furthermore, these bands are observed at 1600, 1490, 1494, 1450, and 698 cm⁻¹. -1 The characteristic band of the benzene ring is displayed at 1730 cm⁻¹, and at 1730 cm⁻¹... -1The stretching vibration band of the C=O bond is visible. The infrared peak of the polymer disappears after calcination. The morphology of the particles was observed using a Japanese 7610F scanning electron microscope and a US Talos F200S transmission electron microscope, and the results are as follows. Figure 2 b and Figure 3 As shown in b, multi-level silicon-based particles were successfully prepared, and after calcination, internal cavities were formed with a shell thickness greater than that of SOB1. The fluorescence intensity of the particle solution was measured using a British FSP920 fluorescence spectrometer, and the results are as follows. Figure 4 As shown in curve SOB2, the particles exhibit the highest fluorescence emission peak at 420 nm, which is lower than that of curve SOB1.

[0043] In addition, the mechanical properties of the SA / SOB2 composite coating are as follows: Figure 5 The curves are shown in Table 1 for specific data. The tensile strength, elongation at break, and Young's modulus of the SA / SOB2 composite coating are 5.09 MPa, 2078.59%, and 11.20 MPa, respectively. Static water contact angle tests were performed on the film using the seated drop method with a DSA30S optical contact angle meter. Figure 6 It can be seen that the static water contact angle of the film is 111.1°, indicating that the coating exhibits hydrophobicity. Furthermore, as shown in Table 3, the thermal conductivity of the prepared SA / SOB2 composite coating is 0.1120 W·m. -1 ·K -1 The thermal conductivity is significantly lower than that of the original SA film.

[0044] Example 3.

[0045] The synthesis of a nanocomposite coating involves the following specific steps:

[0046] In the first step, 0.48 g of styrene, 0.12 g of butyl acrylate, and 1.8 g of methyltriethoxysilane were ultrasonically dispersed at 40 Hz for 5 min and mixed thoroughly. The mixture was then added dropwise to a hydrochloric acid aqueous solution with a pH of 3.5 at an injection rate of 0.4 g / min. After stirring at 250 rpm at room temperature for 1 h, ammonia was added to adjust the pH of the system to 10. Stirring was continued at 250 rpm for 50 min at room temperature. Then, N2 was introduced to remove air, and the mixture was heated to 70 °C. 0.0036 g of KPS dissolved in 5 mL of distilled water was added dropwise. The stirring speed was reduced by 150 rpm, and the reaction was carried out for 2 h to obtain multi-level structured particles. The particles were calcined in a muffle furnace at 500 °C for 5 h to obtain multi-level structured hollow particles (SOB3).

[0047] The second step involves adding 0.1g of SOB3 powder to 10g of SA emulsion under magnetic stirring at 1000rpm to obtain a stable SA / SOB3 dispersion; coating 10g of SA / SOB3 dispersion onto release paper and drying at room temperature for 24h to obtain an SA / SOB3 composite coating.

[0048] Fourier transform infrared (FTIR) spectroscopy was performed on SOB3 particles before and after calcination using a German Tensor-27 spectrometer. The results are as follows: Figure 1 As shown. Particles at 1126, 1037, and 437 cm⁻¹. -1 The area shows stretching and bending vibrational bands of Si-O-Si(Si-OH) bonds at 1270 and 777 cm⁻¹. -1 The text describes the stretching and bending vibrational bands of the Si-CH3 bonds. Furthermore, these bands are observed at 1600, 1490, 1494, 1450, and 698 cm⁻¹. -1 The characteristic band of the benzene ring is displayed at 1730 cm⁻¹, and at 1730 cm⁻¹... -1 The stretching vibration band of the C=O bond is visible. The infrared peak of the polymer disappears after calcination. The morphology of the particles was observed using a Japanese 7610F scanning electron microscope and a US Talos F200S transmission electron microscope, and the results are as follows. Figure 2 c and Figure 3 As shown in c, multi-level structured silicon-based particles were successfully prepared, and after calcination, internal cavities were formed with a shell thickness greater than that of SOB. 1-2 The fluorescence intensity of the particle solution was measured using a British FSP920 fluorescence spectrometer, and the results are as follows: Figure 4 As shown in the curve SOB3, the particle exhibits the highest intensity fluorescence emission peak at 420 nm, which is lower than that of curve SOB. 1-2 .

[0049] In addition, the mechanical properties of the SA / SOB3 composite coating are as follows: Figure 5 As shown in the curve, specific data are shown in Table 1. The tensile strength, elongation at break, and Young's modulus of the SA / SOB3 composite coating are 5.19 MPa, 2006.19%, and 10.4 MJ / m, respectively. 3 The static water contact angle of the thin film was tested using the droplet method with a DSA30S optical contact angle meter. Figure 6 It can be seen that the static water contact angle of the film is 111.6°, indicating that the coating exhibits hydrophobicity. Furthermore, as shown in Table 3, the thermal conductivity of the prepared SA / SOB3 composite coating is 0.1311 W·m. -1 ·K -1 The thermal conductivity is significantly lower than that of the original SA film.

[0050] Example 4.

[0051] The synthesis of a nanocomposite coating involves the following specific steps:

[0052] In the first step, 0.384 g of styrene, 0.096 g of butyl acrylate, and 1.92 g of methyltriethoxysilane were ultrasonically dispersed at 40 Hz for 5 min and mixed thoroughly. The mixture was then added dropwise to a hydrochloric acid aqueous solution with a pH of 3.5 at an injection rate of 0.4 g / min. After stirring at 250 rpm at room temperature for 1 h, ammonia was added to adjust the pH of the system to 10. Stirring was continued at 250 rpm for 50 min at room temperature. Then, N2 was introduced to remove air, and the mixture was heated to 70 °C. 0.0029 g of KPS dissolved in 5 mL of distilled water was added dropwise. The stirring speed was reduced by 150 rpm, and the reaction was carried out for 2 h to obtain multi-level structured particles. The particles were calcined in a muffle furnace at 500 °C for 5 h to obtain multi-level structured hollow particles (SOB4).

[0053] The second step involves adding 0.1g of SOB4 powder to 10g of SA emulsion under magnetic stirring at 1000rpm to obtain a stable SA / SOB4 dispersion; coating 10g of SA / SOB4 dispersion onto release paper and drying at room temperature for 24h to obtain an SA / SOB4 composite coating.

[0054] Fourier transform infrared (FTIR) spectroscopy was performed on SOB4 particles before and after calcination using a German Tensor-27 spectrometer. The results are as follows: Figure 1 As shown. Particles at 1126, 1037, and 437 cm⁻¹. -1 The area shows stretching and bending vibrational bands of Si-O-Si(Si-OH) bonds at 1270 and 777 cm⁻¹. -1 The text describes the stretching and bending vibrational bands of the Si-CH3 bonds. Furthermore, these bands are observed at 1600, 1490, 1494, 1450, and 698 cm⁻¹. -1 The characteristic band of the benzene ring is displayed at 1730 cm⁻¹, and at 1730 cm⁻¹... -1 The stretching vibration band of the C=O bond is visible. The infrared peak of the polymer disappears after calcination. The morphology of the particles was observed using a Japanese 7610F scanning electron microscope and a US Talos F200S transmission electron microscope, and the results are as follows. Figure 2 d and Figure 3 As shown in Figure d, the particles were successfully prepared, and the protruding structure on the particle surface disappeared. After calcination, the internal cavity was difficult to observe due to the excessively thick shell. The fluorescence intensity of the particle solution was measured using a British FSP920 fluorescence spectrometer, and the results are as follows. Figure 4 As shown in curve SOB4, the particles exhibit the highest fluorescence emission peak at 420 nm, which is lower than that of curve SOB. 1-3 .

[0055] In addition, the mechanical properties of the SA / SOB4 composite coating are as follows: Figure 5 The curves are shown in Table 1 for specific data. The tensile strength, elongation at break, and Young's modulus of the SA / SOB4 composite coating are 5.32 MPa, 2156.05%, and 9.98 MPa, respectively. Static water contact angle tests were performed on the film using the seated drop method with a DSA30S optical contact angle meter. Figure 6 It can be seen that the static water contact angle of the film is 110.57°, indicating that the coating exhibits hydrophobicity. Furthermore, as shown in Table 3, the thermal conductivity of the prepared SA / SOB4 composite coating is 0.1320 W·m. -1 ·K -1 The thermal conductivity is significantly lower than that of the original SA film.

[0056] Comparative Example 1.

[0057] The synthesis of an aqueous styrene-acrylic emulsion (SA) involves the following steps:

[0058] Add SDS to 50 mL of deionized water and purge with nitrogen for 15 min to remove air. Then, sonicate 3.0 g St and 1.8 g BA at 40 Hz for 5 min. Add the mixture dropwise to 50 mL of distilled water at a rate of 0.4 g / min using a syringe pump and stir at 250 rpm for 1 h. Heat the system to 70 °C, reduce the stirring speed to 150 rpm, dissolve 0.03 g KPS in 5 mL of distilled water and add it dropwise. Stir for 3 h to obtain styrene-acrylic emulsion (SA).

[0059] The second step is to coat 10g of SA emulsion onto release paper and dry it at room temperature for 24 hours to obtain an SA coating.

[0060] The mechanical properties of SA coatings include Figure 5 The curves are shown in the table below, and the specific data are shown in Table 1. The tensile strength, elongation at break, and Young's modulus of the SA coating are 3.34 MPa, 2378.22%, and 1.9 MPa, respectively. The static water contact angle of the film was tested using the droplet method with a DSA30S optical contact angle meter. Figure 6 It can be seen that the static water contact angle of the film is 87.3°, indicating that the coating exhibits hydrophilicity. Table 3 shows that the thermal conductivity of the SA coating is 0.1348 W·m. -1 ·K -1 .

[0061] Through Examples 1-4 and Comparative Example 1, we can see that the SA coating in Comparative Example 1 has poor mechanical properties and the coating surface is hydrophilic, which also limits the application of the SA coating. After modification with nanoparticles in Examples 1-4, the nanocomposite coating SA / SOB... xCompared to the original SA coating, the mechanical properties are enhanced, and the coating has changed from hydrophilic to hydrophobic, which effectively extends the coating's service life in complex environments and enhances its protective ability against the substrate. Furthermore, due to the presence of the particle cavity structure, the silicon-based nanoparticles also significantly reduce the thermal conductivity of the original SA coating, while also endowing the coating with photoluminescence properties, greatly expanding its development potential in the field of multifunctional coatings.

[0062] Through Examples 1-4, we can see that different particle morphologies have different effects on coating properties. With increasing MTES content, the particles change from a bowl-shaped structure to a spherical shape, the surface area gradually decreases, the contact area with the coating emulsion decreases, and the particle mass also increases, posing a challenge to achieving uniform particle dispersion. This leads to greater phase separation when mixed with the coating, thus failing to effectively improve the mechanical properties of the coating. The thermal conductivity of SA / SOB1 decreases significantly because its protruding hollow structure can encapsulate more air to block heat transfer. With increasing MTES content, the particle shell becomes thicker, resulting in poorer thermal insulation. Furthermore, the decrease in particle fluorescence intensity increases with increasing MTES content, because defects are generated on the particle surface; as the distance decreases, these defects are more likely to transform into stable structures.

[0063] Table 1. SA and SA / SOB x Mechanical property parameters of thin films

[0064]

[0065] Table 2. SA and SA / SOB x Water contact angle of coating

[0066]

[0067] Table 3. SA and SA / SOB x Thermal conductivity of the coating

[0068]

[0069] In summary, this invention successfully prepared a nanocomposite coating filled with hierarchical silicon-based particles. (The coating is made from SOB.) x SA / SOB obtained by blending with SA x The coating exhibits excellent mechanical properties. Furthermore, the styrene-acrylic coating containing hierarchical hollow particles reduces the thermal conductivity of the original styrene-acrylic coating and displays a strong blue fluorescence effect. This work provides a simple method for preparing photoluminescent, enhanced, and thermally insulating nanocomposite coatings.

[0070] Matters not covered in this invention are common knowledge.

Claims

1. A method for preparing a photoluminescent, enhanced, and thermally insulating nanocomposite coating, characterized in that, The method includes the following steps: The first step involves adding styrene, compound A, and compound B to a reactor, and then adding the mixture dropwise to a hydrochloric acid aqueous solution with a pH of 3-4. After reacting for 1-2 hours, ammonia is added to adjust the pH of the system to 9-11. After reacting for 0.5-1 hours, the mixture is heated to 60-80 °C under a nitrogen atmosphere, and an initiator solution is added dropwise. After reacting for 2-4 hours, multi-level structured particles are obtained. The particles are then calcined in a muffle furnace at 300-500 °C for 3-7 hours to obtain multi-level structured hollow particles (SOB). The mass ratio of styrene to compound A is 1:0.25~4; the mass ratio of the total mass of styrene and compound A to compound B is 1:0.25~4; the mass of the initiator is 0.3%~1.0% of the total mass of styrene and compound A; and the concentration of ammonia is 28%. Compound A is one or more of acrylates; compound B is one or more of methyltriethoxysilane, phenyltriethoxysilane, ethyltriethoxysilane, or tridecafluorooctyltriethoxysilane. The initiator is one or more of the water-soluble initiators potassium persulfate, ammonium persulfate, azobisisobutyramidine hydrochloride, and azobisisobutyramidine imidazoline hydrochloride; The second step involves adding the calcined multi-level hollow particles to the matrix latex under magnetic stirring to obtain a matrix / SOB dispersion. The mass ratio of SOB particles to matrix emulsion is 1:50~200; the matrix emulsion is a water-based coating emulsion. The third step is to coat the matrix / SOB dispersion obtained in the second step onto the substrate and dry it at room temperature for 12-36 h to obtain the matrix / SOB composite coating. Among them, each 5×5 cm 2 The substrate is coated with 10-20 g of dispersion.

2. The method for preparing the photoluminescent, enhanced, and thermally insulating nanocomposite coating as described in claim 1, characterized in that, Compound A is n-butyl acrylate, tert-butyl acrylate, or octadecyl acrylate.

3. The method for preparing the photoluminescent, enhanced, and thermally insulating nanocomposite coating as described in claim 1, characterized in that, The matrix latex is specifically an aqueous styrene-acrylic emulsion, a polyurethane emulsion, or a polyvinyl acetate emulsion.

4. The method for preparing the photoluminescent, enhanced, and thermally insulating nanocomposite coating as described in claim 1, characterized in that, The mixture is added dropwise in the first step over a period of 10 to 30 minutes; the magnetic stirring speed in the second step is 800 to 1200 rpm.

5. The method for preparing the photoluminescent, enhanced, and thermally insulating nanocomposite coating as described in claim 1, characterized in that, The substrate is specifically glass or a polypropylene film.

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