Three-phase nano particle with core-shell-feather structure as well as preparation method and application of three-phase nano particle

Abstract

The invention relates to a three-phase nanoparticle with a core-shell-feather structure as well as a preparation method and application of the three-phase nanoparticle. The particle comprises a SiO2 core, a ZrO2 shell and a ZnO-coated PSBMA pinniform structure attached to the shell layer, wherein the mass ratio of the core to the shell to the pinniform structure is 1: 2: 0.1; znO is discretely distributed in an island shape, and the adhesive strength is 50-80 nN. The preparation method comprises the following steps: (1) preparing hollow SiO2 through a CTAB template method, and removing CTAB through gradient calcination; (2) ZrOCl2 is hydrolyzed, and a ZrO2 shell with the thickness of 10-20 nm is deposited on the surface of SiO2; and (3) carrying out ball-milling assembly on ZnO coated PSBMA and core-shell particles according to a mass ratio of 0.8: 10 (the diameter of zirconium beads is 0.3 mm, the filling rate is 60-65%, and the rotating speed is 300rpm). When the three-phase nano particles provided by the invention are used for coating liquid, the light transmittance is improved to 3.4%, the hardness reaches 4H, and the self-cleaning period is prolonged to 180 days.

Description

Technical Field

[0001] This invention relates to the field of coating solution material preparation technology, and in particular to a three-phase nanoparticle with a core-shell-feather structure, its preparation method and application. Background Technology

[0002] Current photovoltaic glass coatings mainly rely on single superhydrophilic or superhydrophobic surface technologies: superhydrophilic coatings (contact angle <90°) are prone to inorganic fouling due to water film retention; superhydrophobic coatings (contact angle >150°) are difficult to effectively degrade organic pollutants and have insufficient mechanical strength (hardness ≤1H). Existing nanoparticle structure designs fail to synergistically integrate hydrophobicity and photocatalytic activity, and the ball milling assembly process easily damages particle integrity, limiting the improvement of coating performance. Summary of the Invention

[0003] This application provides a three-phase nanoparticle with a core-shell-feather structure, which solves the technical problems of short self-cleaning cycle, limited light transmittance improvement, and insufficient mechanical strength in existing photovoltaic glass coating materials. By constructing a SiO2@ZrO2@Polymer / ZnO@PSBMA core-shell-feather heterostructure and optimizing the ball milling assembly process, the synergistic effect of hydrophobic rinsing and photocatalytic degradation is achieved, significantly extending the self-cleaning cycle to 180 days, while improving the light transmittance gain to 3.4% and the hardness to 4H.

[0004] This application provides a three-phase nanoparticle with a core-shell-feather structure, characterized in that it includes a SiO2 core, a ZrO2 shell, and a ZnO@PSBMA feather structure attached to the shell, with a core:shell:feather mass ratio of 1:2:0.1, ZnO is distributed in an island-like discrete manner without a continuous coating layer, and the ZnO adhesion strength is 50-80 nN.

[0005] This invention application also provides a method for preparing triphase nanoparticles with a core-shell-feather structure, characterized by comprising the following steps:

[0006] Step 1: Preparation of SiO2@ZrO2@Polymer core-shell particles

[0007] ① Hexadecyltrimethylammonium bromide (CTAB) is first dissolved in an ethanol / water mixture, and then tetraethyl orthosilicate (TEOS) is added. The CTAB content in the ethanol / water mixture is 1.5 wt%. SiO2-CTAB composite particles are prepared by chemical reaction. The SiO2-CTAB composite particles are then subjected to gradient high-temperature calcination to remove CTAB and synthesize hollow SiO2.

[0008] ② Disperse the hollow SiO2 from step ① in ethanol, add ZrOCl2 solution and hydrolyze at 80℃ for 2h, then centrifuge and wash to obtain core layer SiO2@ZrO2, wherein the ZrO2 shell thickness is 10-20nm;

[0009] ③ Prepare an organosilicon-modified acrylate emulsion with a solid content of 40%;

[0010] ④ Disperse the core layer SiO2@ZrO2 obtained in step ② into the organosilicon modified acrylate emulsion obtained in step ③, with the mass ratio of core layer SiO2@ZrO2 to organosilicon modified acrylate emulsion being 1:2. Stir at 60℃ for 2 hours and centrifuge to obtain SiO2@ZrO2@Polymer core-shell particles.

[0011] Step 2: Three-phase nano-ion assembly

[0012] ① ZnO nanoparticles were coated with zwitterionic polymers to obtain ZnO@PSBMA composite particles with photocatalytic activity and controllable hydrophobicity, with a water contact angle of 105°±2°.

[0013] ② The ZnO@PSBMA obtained in step ① is mixed with the SiO2@ZrO2@Polymer core-shell particles obtained in step 1 at a mass ratio of 0.8:10. After ball milling for 3 hours, ZnO@PSBMA is physically anchored to the surface of the core-shell particles with an adhesion strength of 50-80 nN, forming three-phase nanoparticles with a heterogeneous "core-shell-feather" structure.

[0014] Preferably, the high-temperature calcination in step ① of step one specifically includes: calcination at a high temperature of 550℃, holding at 200℃ for 1 hour to remove organic matter, calcination at 400℃ for 2 hours, and calcination at 550℃ for 2 hours.

[0015] Preferably, the ethanol concentration in step ② of step one is 5 wt%, and 0.1 wt% ammonium polyacrylate is added to the ethanol system.

[0016] Preferably, the method for preparing the organosilicon-modified acrylate emulsion in step ③ of step one is as follows:

[0017] A mixture of methyl methacrylate (MMA), butyl acrylate (BA), and γ-methacryloyloxypropyltrimethoxysilane (KH570) monomers was added to an aqueous phase containing sodium dodecyl sulfate (SDS). The mixture was ultrasonically emulsified, oxygen was removed by purging with N2, and the temperature was raised to 75°C. APS solution was added dropwise in three portions at 0 min, 60 min, and 120 min, respectively. The reaction was carried out for 4 h, cooled to 40°C, and the pH was adjusted to 7.5 by adding ammonia water to obtain an organosilicon-modified acrylate emulsion.

[0018] Preferably, the ball milling process in step 2 is as follows: fluorosilane-grafted ZnO and SiO2@ZrO2@Polymer core-shell particles are mixed at a mass ratio of 0.8:10 and added to a ball mill jar. Zirconia grinding balls with a diameter of 0.3 mm and a filling rate of 60-65% are added, and the rotation speed is 300 rpm.

[0019] This application also provides an application of triphase nanoparticles with a core-shell-feather structure in the preparation of coating solutions.

[0020] The technical effects of the embodiments of this application are as follows:

[0021] 1. This invention employs zwitterionic polymers to coat ZnO nanoparticles, resulting in ZnO@PSBMA composite particles with photocatalytic activity and controllable hydrophobicity. The hydrophobic surface lowers the energy barrier for pollutant adhesion, and combined with photocatalytic degradation of organic pollutants, the synergistic effect of these two processes allows rainwater washing and chemical decomposition to occur simultaneously. A contact angle hysteresis angle of 12°±3° further demonstrates the low surface adhesion, solving the problems of inorganic dirt residue easily remaining on traditional hydrophilic surfaces and insufficient photocatalytic activity on superhydrophobic surfaces.

[0022] 2. This invention achieves gradient refraction between the SiO2 core and the ZrO2 shell, increasing the light transmittance to 3.4%. The ZrO2 shell enhances rigidity, while the polymer shell buffers stress, resulting in a hardness of 4H. Detailed Implementation

[0023] To better understand the above technical solution, a detailed explanation is provided below.

[0024] Example 1

[0025] (1) Preparation of SiO2@ZrO2@Polymer core-shell particles

[0026] Raw materials and proportions:

[0027] ①Tetraethyl orthosilicate (TEOS), specification ≥99.9%, weight 100g;

[0028] ② Hexadecyltrimethylammonium bromide (CTAB), mass 8g;

[0029] ③ Zirconium oxychloride (ZrOCl2·8H2O), with a specification of ≥99.9% and a mass of 125g;

[0030] ④ Ammonia water (NH3·H2O), 28wt%, is 120mL;

[0031] ⑤ Anhydrous ethanol, specification ≥99.7%, 500mL;

[0032] The specific experimental procedure is as follows: First, prepare an ethanol / water mixture with a volume ratio of 4:1. Dissolve hexadecyltrimethylammonium bromide (CTAB) in the above ethanol / water mixture, add tetraethyl orthosilicate (TEOS), stir at 40°C for 30 min, add ammonia water dropwise at a rate of 2 mL / min, react at 55°C for 3 h, centrifuge to obtain SiO2-CTAB composite particles, keep warm at 200°C for 1 h to remove organic matter, increase the temperature at a programmed rate of 5°C / min, calcine at 400°C for 2 h, calcine at 550°C for 2 h to remove CTAB, and synthesize hollow SiO2 with a particle size of 80±5 nm and a wall thickness of 10 nm.

[0033] The hollow SiO2 prepared above was dispersed in 5wt% ethanol, and 0.2mol / L ZrOCl2 solution was added. The pH of the ZrOCl2 solution was adjusted to 4.0±0.2 with ammonia to avoid ZrO2 precipitation too quickly. After hydrolysis at 80℃ for 2h, the solution was centrifuged and washed to obtain core layer SiO2@ZrO2 with a ZrO2 shell thickness of 15nm. The refractive index of the ZrO2 shell with a thickness of 15nm is 1.30, and the surface roughness is 4.2.

[0034] In other embodiments, 0.1 wt% ammonium polyacrylate may be added to the 5 wt% ethanol system to prevent SiO2@ZrO2 agglomeration.

[0035] (2) Preparation of the shell

[0036] Raw materials and proportions:

[0037] Industrial grade methyl methacrylate (MMA) 60g, industrial grade butyl acrylate (BA) 30g, γ-methacryloyloxypropyltrimethoxysilane (KH570) 10g, specification ≥98%, ammonium persulfate (APS) 0.5g, sodium dodecyl sulfate (SDS) 1.5g.

[0038] The specific steps are as follows:

[0039] A mixture of methyl methacrylate (MMA), butyl acrylate (BA), and γ-methacryloyloxypropyltrimethoxysilane (KH570) monomers was added to an aqueous phase containing sodium dodecyl sulfate (SDS). The SDS concentration was 1.5% of the monomer mass. The mixture was ultrasonically emulsified at 300W for 10 minutes. The emulsion particle size after ultrasonic emulsification should be ≤100nm. Oxygen was removed by purging with N2, and the temperature was raised to 75℃. 5wt% APS solution was added in three separate additions at 0, 60, and 120 minutes, controlling the exothermic rate. The reaction was allowed to proceed for 4 hours, then cooled to 40℃. The pH was adjusted to 7.5 with ammonia to obtain a silicone-modified acrylate emulsion with a solid content of 40%. A pH of 7.5 ensured that the degree of hydrolysis of the KH570 silanol groups was ≤30%, preventing emulsion gelation.

[0040] The core layer SiO2@ZrO2 prepared in step (1) was dispersed in the organosilicon-modified acrylate emulsion prepared in step (2), with the mass ratio of core layer SiO2@ZrO2 to organosilicon-modified acrylate emulsion being 1:2. The mixture was stirred at 60°C for 2 hours and centrifuged to obtain SiO2@ZrO2@Polymer core-shell particles.

[0041] (3) Three-phase nano-ion assembly

[0042] ① Add 20g of nano ZnO to 200mL of ethanol, ultrasonically disperse for 30min at 300W, then add 0.6g of 3wt% KH-550, stir at 40℃ for 4h at 400rpm, centrifuge and wash 3 times to remove free silane, and obtain aminated ZnO.

[0043] 20g of sulfobetaine methacrylate (SBMA) was added to the prepared aminated ZnO and dissolved in 200mL of deionized water. The mixture was deoxygenated by passing N2 through it for 30min, heated to 65℃, and 0.8g of K2S2O8 was added. The mixture was polymerized at a constant temperature for 8h with a stirring rate of 300rpm. The reaction solution was purified by centrifugation, ultrafiltration, and dialysis at 3000rpm for 30min. After freeze-drying, a white powder ZnO@PSBMA was obtained with a contact angle of 105±2°.

[0044] ② The ZnO@PSBMA obtained in step ① is mixed with the SiO2@ZrO2@Polymer core-shell particles obtained in step (2). The mass ratio of fluorosilane-grafted ZnO to SiO2@ZrO2@Polymer core-shell particles is 0.8:10. The mixture is added to a ball mill jar, and zirconia grinding balls with a diameter of 0.3 mm and a filling rate of 60-65% are added. The milling speed is 300 rpm. After 3 hours of ball milling, the final product of "core-shell-feather" three-phase nanoparticles is obtained. The mass ratio of core:shell:feather is 1:2:0.1. ZnO is distributed in an island-like discrete manner without a continuous coating layer. The adhesion strength of ZnO is 50-80 nN. Among them, the SiO2@ZrO2@Polymer core-shell particles were measured by nanoindentation method, and the result was 120±15nN, which is higher than the ball milling shear force. The optimized design of the diameter and filling rate of the zirconia grinding balls in the ball milling process controls the shear force within the range of 50-100nN, which is lower than the breakage threshold of SiO2@ZrO2@Polymer core-shell particles, thus ensuring the structural integrity.

[0045] Example 2

[0046] Preparation of coating solution based on three-phase nanoparticles

[0047] Raw materials and their proportions by weight: 15 parts of three-phase nanoparticles; 50 parts of propylene glycol methyl ether acetate (PMA);

[0048] 30 parts ethanol; 5 parts polyether-modified siloxane.

[0049] Ethanol and PMA were mixed in a dispersion vessel, and three-phase nanoparticles were slowly added while stirring at 800 rpm at a feeding rate ≤1 kg / min. After high-speed dispersion, the mixture was subjected to primary grinding in a sand mill for 2 hours. The zirconium beads in the sand mill had a particle size of 0.3 mm and a filling rate of 70% to prevent particle breakage. The target particle size was D90 < 100 nm. After grinding, the slurry was cooled to 30°C, and 5 parts of polyether-modified siloxane were added. The mixture was first stirred at low speed and then finely ground in a sand mill for 1 hour. The particle size distribution Span value was < 0.35. The viscosity was measured using a rheometer, with a target viscosity of 35 ± 2 cP. If the viscosity was too thick, ethanol was added, ≤1 part each time; if the viscosity was too thin, PMA was added, ≤0.5 parts each time. The mixture was then vacuum degassed until no visible bubbles were observed. After step-depressurization vacuum degasing and aging, the coating solution was obtained. The step-depressurization vacuum degasing process can prevent boiling over. Specifically, the pressure was maintained at 0.05 MPa for 10 minutes, -0.07 MPa for 10 minutes, and -0.09 MPa until no bubbles were observed.

[0050] Example 3

[0051] Except for the following steps in Example 1, where the mass of zirconium oxychloride (ZrOCl2·8H2O) was changed to 82g, dissolved in 200mL of deionized water to prepare a 0.2mol / L solution, the pH was adjusted to 4.5±0.1 with ammonia, hydrolyzed at 70℃ for 2h, and centrifuged at 8000rpm×10min, the resulting SiO2@ZrO2 core-shell particles had a ZrO2 shell thickness of 10±1nm and a surface roughness of Ra = 3.2nm according to AFM testing. All other parameters were consistent with the Example 1. The water contact angle of the obtained SiO2@ZrO2 core-shell particles was 82°±3° (measured according to ASTM D7334 standard, droplet volume 2μL), and the coating adhesion was rated as 4B according to the cross-cut adhesion test (ASTM D3359). After ball milling ZnO@PSBMA and the core-shell particles at a mass ratio of 0.8:10, the water contact angle of the three-phase particles was increased to 105°±2°, and the self-cleaning cycle was shortened to 120 days. This is mainly attributed to the partial anchoring of contaminants caused by the surface roughness of the core-shell (Ra=3.2nm). However, the superhydrophilic properties of the zwitterionic polymer still achieve performance superior to traditional coatings.

[0052] Example 4

[0053] Except for the following steps in Example 1, where the mass of zirconium oxychloride (ZrOCl2·8H2O) was changed to 163g, dissolved in 480mL of deionized water to prepare a 0.2mol / L solution, 0.3mL of concentrated HNO3 (65wt%) was added, the pH was adjusted to 3.8±0.1, hydrolyzed at 90℃ for 3h, centrifuged (8000rpm×10min), and washed three times with 0.01mol / L ammonia water to prepare a ZrO2 shell thickness of 20±2nm, all other steps were consistent with the Example 1. AFM testing showed that the surface roughness Ra of the 20nm shell thickness group was 5.6±0.3nm (scanning area 5×5μm). While the higher roughness enhanced mechanical interlocking, resulting in a hardness of 4H, it also lowered the contaminant adhesion barrier (contact angle hysteresis angle reached 38°), thus reducing the self-cleaning cycle to 100 days. In this embodiment, the adhesion of the coating in the cross-cut adhesion test is grade 3B, which can be improved to grade 4B by adding 0.5wt% silane coupling agent KH-560 as a post-treatment.

[0054] The coating solutions prepared by the three-phase nano-ions in Examples 1, 3, and 4 were applied to photovoltaic glass. Compared with traditional single-layer AR coating solutions, the following technical indicators were obtained:

[0055] 1. The photocatalytic degradation of methylene blue in the coated glass of Example 1 was tested using general testing standards. The results showed that the degradation efficiency of ZnO@PSBMA reached 92% within 4 hours.

[0056] 2. The ZnO@PSBMA in Example 1 was tested for contact angle and hysteresis angle using general testing standards. The hysteresis angle was 12°±3°, indicating that the hydrophobic surface has low adhesion and is conducive to the removal of pollutants.

[0057] 3. Simulated rainwater scouring tests (tilt angle 30°, flow rate 2 L / min) and photocatalytic degradation rate tests were conducted on the film glass in Examples 1 and 2. The results showed that: in Example 1, the residual amount of particulate pollutants on the surface decreased by 78%, with hydrophobicity dominating the scouring process; in Example 2, the residual amount of particulate pollutants on the surface decreased by 52%, with hydrophilicity causing some particles to be retained. The photocatalytic reaction rate constant k = 0.025 min in the methylene blue degradation experiment was also observed. -1 Example 2: k = 0.018 min -1 The main reason for the difference is the difference in the dispersion of ZnO.

[0058] The technical indicators are compared in the table below:

[0059]

[0060] The comparative results show that: 1. The coating solution based on three-phase nanoparticles can improve the light transmittance, hardness, and salt spray resistance of photovoltaic glass. When the ZrO2 shell thickness is 10-20 nm, the light transmittance changes with the refractive index gradient in a parabolic peak value, with the best performance at 15 nm. Photovoltaic glass using the coating solution based on three-phase nanoparticles has self-cleaning ability and can be cleaned once every 180 days, which greatly reduces the maintenance cost of photovoltaic glass. It is particularly noteworthy that the main reason why the 120-day cleaning performance in Example 2 is lower than that in Example 1 is that although the hydrophilic surface 82° in Example 2 is conducive to water film formation, it is easy to retain inorganic dirt, while the hydrophobic surface can reduce such adhesion. In addition, the photocatalytic efficiency is limited by the ZnO dispersion. In Example 1, the "feather" structure of ZnO@PSBMA is more uniformly distributed, which improves the utilization rate of active sites.

[0061] 2. This invention addresses the technical problem that traditional self-cleaning coatings rely on a single superhydrophilic (contact angle < 90°) or superhydrophobic (contact angle > 150°) surface, both of which have limitations. Through the unique design of ZnO@PSBMA, combining the dual mechanisms of hydrophobic surface and photocatalytic decomposition, the ZnO hydrophobic surface can reduce the energy barrier for pollutant adhesion, making particulate pollutants easier to be washed away by rainwater. The ZnO photocatalytic decomposition performance can generate active oxygen species under light irradiation, degrading organic pollutants and compensating for the limitations of hydrophobic surfaces in removing organic pollutants. The synergistic effect of the two overcomes the defects of a single hydrophilic or hydrophobic surface, achieving a self-cleaning cycle of 180 days.

[0062] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0063] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A triphase nanoparticle with a core-shell-feather structure, characterized in that, It includes a SiO2 core, a ZrO2 shell, and a ZnO@PSBMA feather structure attached to the shell. The core:shell:feather mass ratio is 1:2:0.

1. The ZnO is distributed in a discrete island-like pattern without a continuous coating layer. The ZnO adhesion strength is 50-80 nN.

2. The method for preparing three-phase nanoparticles as described in claim 1, characterized in that, Includes the following steps: Step 1: Preparation of SiO2@ZrO2@Polymer core-shell particles ① Hexadecyltrimethylammonium bromide (CTAB) is first dissolved in an ethanol / water mixture, and then tetraethyl orthosilicate (TEOS) is added. The CTAB content in the ethanol / water mixture is 1.5 wt%. SiO2-CTAB composite particles are prepared by chemical reaction. The SiO2-CTAB composite particles are then subjected to gradient high-temperature calcination to remove CTAB and synthesize hollow SiO2. ② Disperse the hollow SiO2 from step ① in ethanol, add ZrOCl2 solution and hydrolyze at 80℃ for 2h, then centrifuge and wash to obtain core layer SiO2@ZrO2, wherein the ZrO2 shell thickness is 10-20nm; ③ Prepare an organosilicon-modified acrylate emulsion with a solid content of 40%; ④ Disperse the core layer SiO2@ZrO2 obtained in step ② into the organosilicon modified acrylate emulsion obtained in step ③, with the mass ratio of core layer SiO2@ZrO2 to organosilicon modified acrylate emulsion being 1:

2. Stir at 60℃ for 2 hours and centrifuge to obtain SiO2@ZrO2@Polymer core-shell particles. Step 2: Three-phase nano-ion assembly ① ZnO nanoparticles were coated with zwitterionic polymers to obtain ZnO@PSBMA composite particles with photocatalytic activity and controllable hydrophobicity, with a water contact angle of 105°±2°. ② The ZnO@PSBMA obtained in step ① is mixed with the SiO2@ZrO2@Polymer core-shell particles obtained in step 1 at a mass ratio of 0.8:

10. After ball milling for 3 hours, ZnO@PSBMA is physically anchored to the surface of the core-shell particles with an adhesion strength of 50-80 nN, forming three-phase nanoparticles with a "core-shell-feather" heterostructure.

3. The preparation method according to claim 1, characterized in that, The high-temperature calcination in step 1, ①, specifically involves: calcination at a high temperature of 550℃, holding at 200℃ for 1 hour to remove organic matter, calcination at 400℃ for 2 hours, and calcination at 550℃ for 2 hours.

4. The preparation method according to claim 1, characterized in that, In step 1, ②, the ethanol concentration is 5 wt%, and 0.1 wt% ammonium polyacrylate is added to the ethanol system.

5. The preparation method according to claim 1, characterized in that, The preparation method of the organosilicon-modified acrylate emulsion in step 1, ③ is as follows: A mixture of methyl methacrylate (MMA), butyl acrylate (BA), and γ-methacryloyloxypropyltrimethoxysilane (KH570) monomers was added to an aqueous phase containing sodium dodecyl sulfate (SDS). The mixture was ultrasonically emulsified, oxygen was removed by purging with N2, and the temperature was raised to 75°C. APS solution was added dropwise in three portions at 0 min, 60 min, and 120 min, respectively. The reaction was carried out for 4 h, cooled to 40°C, and the pH was adjusted to 7.5 by adding ammonia water to obtain an organosilicon-modified acrylate emulsion.

6. The preparation method according to claim 1, characterized in that, The ball milling process in step 2 is as follows: fluorosilane-grafted ZnO and SiO2@ZrO2@Polymer core-shell particles are mixed at a mass ratio of 0.8:10 and then added to a ball mill jar. Zirconia grinding balls with a diameter of 0.3 mm and a filling rate of 60-65% are added, and the rotation speed is 300 rpm.

7. The application of the three-phase nanoparticles as described in claim 1, characterized in that, The application of the three-phase nanoparticles in the preparation of the coating solution.

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