Method for preparing multicolor microspheres through gold nanocluster assisted emulsion interfacial polymerization and application

Abstract

The invention discloses a method for preparing multicolor microspheres through gold nanocluster assisted emulsion interfacial polymerization and application, and relates to the technical field of optical composite materials. The method comprises the following steps: (1) mixing and reacting chloroauric acid and reduced glutathione in an aqueous solution to obtain a gold nano-cluster solution; (2) adding a polyamine compound, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide into the gold nano-cluster solution obtained in the step (1), and carrying out a reaction so as to obtain an amino-functionalized gold nano-cluster solution; and (3) mixing the aqueous phase and the organic phase, carrying out homogenization treatment to form an emulsion, and carrying out a reaction to obtain the multicolor microspheres, wherein the aqueous phase comprises an aqueous solution obtained by mixing the amino-functionalized gold nano-cluster solution and a polyvinyl alcohol solution, and the organic phase comprises a solution formed by dissolving isocyanate and fluorescent conjugated molecules in an organic solvent. The multicolor microspheres have good application value in the field of optical functional coatings.

Description

Technical Field

[0001] This invention relates to the field of luminescent composite materials technology, and in particular to a method and application for preparing multicolor microspheres by gold nanocluster-assisted emulsion interfacial polymerization. Background Technology

[0002] As a classic dispersion system composed of two immiscible liquids, emulsions have consistently maintained a high level of research attention and application potential in numerous fields due to their rich and diverse structural properties. From everyday cosmetics and health-related biomedical fields to the agrochemical industry that ensures agricultural production, and further to the advanced materials synthesis field that drives the development of new materials, emulsion systems have demonstrated broad and important application value, becoming one of the key foundational systems supporting technological innovation in multiple industries.

[0003] However, emulsion systems inherently possess significant thermodynamic instability. Even in an ideal environment free from external disturbances, driven by the intrinsic thermodynamic factor of minimizing interfacial energy, droplets within the system will gradually coalesce over time. This inherent instability presents a series of major challenges to the practical application of emulsions: on the one hand, it severely limits the shelf life of emulsion products, significantly shortening their effective usage period; on the other hand, during production and processing, uncontrolled droplet coalescence makes it difficult to precisely control process parameters, greatly affecting product quality stability. Especially in cutting-edge applications such as nanomaterial template preparation, where extremely high precision is required, problems such as size inhomogeneity and structural defects caused by droplet coalescence directly restrict the industrialization and performance breakthroughs of related technologies. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a method and application for preparing multicolor microspheres via gold nanocluster-assisted emulsion interfacial polymerization. The technical solution is as follows:

[0005] A method for preparing multicolor microspheres by gold nanocluster-assisted emulsion interfacial polymerization, the method comprising:

[0006] (1) Chloroauric acid and reduced glutathione are mixed in an aqueous solution and reacted at 60-80℃. After the reaction is completed, dialysis is performed to obtain a gold nanocluster solution.

[0007] (2) Add polyamine compound, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to the gold nanocluster solution described in step (1), react, and perform dialysis after the reaction to obtain amino-functionalized gold nanocluster solution.

[0008] (3) The aqueous phase includes: the aqueous solution obtained by mixing the amino-functionalized gold nanocluster solution and the polyvinyl alcohol solution in step (2), and the organic phase includes: the solution formed by dissolving isocyanate and fluorescent conjugated molecules in an organic solvent. The aqueous phase and the organic phase are mixed in a volume ratio of 1:1 to 10:1, homogenized to form an emulsion, and then reacted for 12-24 hours. The reaction solution is centrifuged, and the solid is washed and dried to obtain multicolor microspheres.

[0009] Optionally, in step (1), the molar ratio of chloroauric acid and reduced glutathione is 1:2 to 1:1;

[0010] And / or, in step (1), the chemical reaction formula is:

[0011] ;

[0012] And / or, in step (1), the reaction time is 12-24 hours;

[0013] And / or, in step (1), the dialysis process is as follows: the reaction product is dialyzed using a dialysis bag with a molecular weight cutoff of 700-1500 Da and deionized water as the dialysis medium, and the retained solution in the dialysis bag is collected to obtain the gold nanocluster solution.

[0014] Optionally, in step (2), the polyamine compound is selected from one or more of ethylenediamine, hexamethylenediamine, octyldiamine, p-xylenediamine, m-xylenediamine, and diethyltoluenediamine;

[0015] And / or, in step (2), the molar ratio of the polyamine compound to the gold nanoclusters is 1:1-36:1;

[0016] And / or, in step (2), the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to the gold nanoclusters is 200:1-100:1;

[0017] And / or, in step (2), the molar ratio of the N-hydroxysuccinimide to the gold nanoclusters is 300:1-400:1;

[0018] And / or, in step (2), the chemical reaction formula is: ;

[0019] And / or, in step (2), the reaction temperature is room temperature;

[0020] And / or, in step (2), the reaction time is 8-24 hours;

[0021] And / or, in step (2), the dialysis treatment is performed as follows: the reaction product is dialyzed using a dialysis bag with a molecular weight cutoff of 700-1500 Da and deionized water as the dialysis medium, and the retained solution in the dialysis bag is collected to obtain the amino-functionalized gold nanocluster solution.

[0022] Optionally, in step (3), the isocyanate is selected from one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and hydrogenated phenylmethane diisocyanate;

[0023] And / or, in step (3), the fluorescent conjugated molecule is selected from one or more of the following: poly(9,9-dioctylfluorene-2,7-diyl), poly(9,9-dioctylfluorene-co-dibenzothiophene-S,S-dioxide), poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole], poly3-hexylthiophene, poly[(9,9-di-n-octylfluorene-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)], and poly[2-methoxy-5-(2'-ethylhexoxy)-1,4-phenyleneethylene].

[0024] And / or, in step (3), the molecular weight of the polyvinyl alcohol is 70,000-90,000 g / mol;

[0025] And / or, in step (3), the organic phase further includes polylactic acid;

[0026] And / or, in step (3), the molecular weight of the polylactic acid is 85,000-90,000 g / mol;

[0027] And / or, in step (3), the organic solvent includes: chloroform, dichloromethane, acetone.

[0028] Optionally, in step (3), the mass percentage of the polyvinyl alcohol solution is 1-10%;

[0029] And / or, in step (3), the volume ratio of the amino-functionalized gold nanocluster solution to the polyvinyl alcohol solution is 15:1-30:1;

[0030] And / or, in step (3), the concentration of the isocyanate compound in the organic phase solution is 0.5-5 M;

[0031] And / or, in step (3), the concentration of the fluorescent conjugated molecule in the organic phase solution is 1-5 M;

[0032] And / or, in step (3), the concentration of polylactic acid in the organic phase solution is 0.1-1 mM;

[0033] And / or, in step (3), the reaction utilizes the two-phase interface of the emulsion droplets of amino-functionalized gold nanoclusters as the reaction site, so that the functional amino groups of the amino-functionalized gold nanoclusters and the isocyanate monomers undergo a polymerization reaction at the two-phase interface, thereby obtaining the polyurea shell material of the multicolor microspheres, and the cavity of the multicolor microspheres is loaded with fluorescent conjugated molecules, thereby obtaining the multicolor microspheres.

[0034] And / or, in step (3), the chemical reaction formula is:

[0035] ;

[0036] In step (3), the role of polyvinyl alcohol is to act as an excipient that stabilizes the emulsion interface;

[0037] The polylactic acid (PLA) acts as an auxiliary conjugated polymer, maintaining the stability of the microsphere structure. Even without the addition of PLA, the microspheres can still maintain their structural integrity.

[0038] The method described yields multicolored microspheres.

[0039] The multicolor microspheres include a polyurea shell material, which is obtained by the polymerization reaction of functional amino groups of amino-functionalized gold nanoclusters with isocyanate monomers, and the cavities of the multicolor microspheres are loaded with fluorescent conjugated molecules.

[0040] The application of the multicolor microspheres in the method of preparing photofunctional coatings.

[0041] A method for preparing a photofunctional coating, the method comprising: coating a solution of the multicolor microspheres onto a solid substrate and drying it to obtain the photofunctional coating.

[0042] The optically functional coating prepared by the method described above.

[0043] Composite material containing the aforementioned photofunctional coating.

[0044] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0045] The technical solution of this invention involves grafting and modifying fluorescent gold nanoclusters and using an emulsion method to create a large number of two-phase interfaces. Through simple mixing, the modified gold nanoclusters are polymerized with isocyanate compounds at the interface. The resulting polymer exhibits stable luminescence, unlike small molecules which are easily quenched. Furthermore, by incorporating conjugated molecules into the oil phase, multicolor microspheres with good stability, high-intensity luminescence, and tunable luminescence properties are prepared.

[0046] This invention discloses a method for preparing multicolor microspheres using gold nanoclusters-assisted emulsion interfacial polymerization. The method utilizes the two-phase interface of stable emulsion droplets containing gold nanoclusters as the reaction site, allowing the functional amino groups of the gold nanoclusters to polymerize with oil-soluble isocyanate monomers at the interface to prepare a polyurea shell material. Fluorescent conjugated molecules are then loaded into the cavity to prepare multicolor microspheres with different luminescent properties. The preparation method provided by this invention is simple and easy to implement, utilizing an emulsion method for interfacial polymerization to prepare stable luminescent composite materials without any external conditions. This composite micromaterial exhibits enhanced fluorescence and stability, making it valuable in the field of photofunctional coatings.

[0047] The microspheres prepared in this invention possess a two-phase environment, which improves the distribution of fluorescent conjugated molecules and luminescent gold nanoclusters. This results in less interference between various luminescent materials and in energy transfer, facilitating control. Furthermore, this unique combination of stability, fluorescence performance, and multicolor luminescence characteristics has significant practical application value: on the one hand, the multicolor luminescence system can effectively distinguish different emitted light signals, significantly reducing mutual interference between signals. On the other hand, by controlling the composition and structure of the luminescent materials, stable regulation of luminescence properties can be achieved, meeting the requirements of different application scenarios for emission wavelength, intensity, and stability. Specifically, the gold nanoclusters emit yellow light and can be combined with fluorescent conjugated molecules emitting blue, yellow, red, etc. Adjusting the composition of the luminescent materials refers to adjusting the ratio of gold nanoclusters to fluorescent conjugated molecules. Controlling the structure of the luminescent materials involves using an emulsion to control the gold nanoclusters on the emulsion surface, while the fluorescent conjugated molecules are mainly distributed inside the emulsion, thus regulating the structure of the luminescent materials. Currently, precisely controlling the partitioned distribution of different luminescent materials within multicolor microspheres remains a pressing technical problem. Therefore, the above-mentioned technical effects of this invention have practical value for the application of photofunctional composite materials in the field of advanced optical technology.

[0048] The method of this invention promotes the reaction by increasing the number of interfaces through an emulsion process. Preferably, the photofunctional microsphere shell is prepared by controlling the concentrations of the added amino-functionalized gold nanoclusters and isocyanate compounds, which is a simple operation. Preferably, the change in emission color is adjusted by adjusting the concentration of the added conjugated molecules. The resulting luminescent composite material can be easily coated, such as by drop coating, exhibiting good luminescent properties and stability, and has great application value in the field of photofunctional coatings. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a transmission electron micrograph of amino-functionalized gold nanoclusters provided in Example 1 of the present invention;

[0051] Figure 2 This is a transmission electron micrograph of multicolor microspheres prepared by gold nanocluster-assisted emulsion interfacial polymerization according to Example 1 of the present invention;

[0052] Figure 3 The fluorescence spectra of multicolor microspheres prepared by gold nanoclusters-assisted emulsion interfacial polymerization with different concentrations of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] under 380 nm incident light excitation are provided in Example 2 of this invention.

[0053] Figure 4 This is the CIE colorimetric diagram of multicolor microspheres prepared by gold nanoclusters-assisted emulsion interfacial polymerization with different concentrations of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] under 380 nm incident light excitation provided in Example 2 of the present invention.

[0054] Figure 5 The results of stability tests on the addition of different concentrations of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] to prepare multicolor microspheres by gold nanocluster-assisted emulsion interfacial polymerization provided in Example 2 of this invention.

[0055] Figure 6 The fluorescence spectra of multicolor microspheres prepared by gold nanocluster-assisted emulsion interfacial polymerization with different concentrations of poly(9,9-dioctylfluorene-2,7-diyl) under 380 nm incident light excitation are provided in Example 3 of this invention.

[0056] Figure 7 The CIE chromaticity diagrams of multicolor microspheres prepared by gold nanocluster-assisted emulsion interfacial polymerization with different concentrations of poly(9,9-dioctylfluorene-2,7-diyl) under 380 nm incident light excitation are provided in Example 3 of this invention.

[0057] Figure 8 The results are the stability test results of adding different concentrations of poly(9,9-dioctylfluorene-2,7-diyl) to the gold cluster-based luminescent composite micromaterials prepared in Example 3;

[0058] Figure 9 The results are the stability test results of adding different concentrations of poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)] to the gold cluster-based luminescent composite micromaterial prepared in Example 4. Detailed Implementation

[0059] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0060] Reduced glutathione, chemically named N-(NL-γ-glutamyl-L-cysteyl)glycine, has the molecular formula C2. 10 H 17 N3O6S has a molecular weight of 307.33.

[0061] The purpose of this invention is to overcome the instability of emulsion systems, the energy transfer of luminescent composite materials, and the difficulty in controlling the luminescence color, and to provide a method for preparing multicolor microspheres by gold nanocluster-assisted emulsion interface polymerization, which can be used to prepare photofunctional coatings.

[0062] To address the challenge of emulsion stability, this invention reveals that ligand-functionalized gold nanoclusters, with their unique structural and performance advantages, represent a revolutionary solution. Specifically, this invention demonstrates that amino-functionalized gold nanoclusters can spontaneously form an ordered assembly layer at the oil-water interface. This assembly layer not only physically prevents direct contact between droplets through steric hindrance but also regulates interfacial tension through surface chemistry, thereby effectively inhibiting droplet aggregation and significantly improving the long-term stability of the emulsion. More importantly, gold nanoclusters possess an extremely high specific surface area, a structural characteristic that allows them to fully participate in interfacial polymerization reactions. During polymerization, gold nanoclusters act as active sites, interacting with monomers to guide the polymerization reaction precisely at the oil-water interface, thus achieving the directional construction of stable emulsion droplets.

[0063] Controlled interfacial polymerization in this Pickering emulsion enables the precise fabrication of cavity-like structures. Modified gold nanoclusters can be used as monomer components in the interfacial polymerization process, and through synergistic polymerization with other monomers, multicolor microspheres with fluorescent properties have been successfully prepared. Additional conjugated molecules are introduced as functional fillers inside the shells of the multicolor microspheres, and multicolor luminescence effects are achieved by utilizing the synergistic effect between multiple luminescent molecules.

[0064] The technical solution of this invention uses an emulsion method to divide a large interface into many smaller interfaces, thereby promoting interfacial polymerization. Preferably, the formation time of the polyurea shell is controlled by adjusting the ratio of gold nanoclusters and isocyanate compounds; increasing the concentration of both can accelerate the reaction rate.

[0065] Furthermore, the technical solution of the present invention can change the luminescence by adding different fluorescent conjugated molecules into the microsphere cavity and adjusting their concentration, thereby achieving full-spectrum regulation, and then coating to prepare a photofunctional coating.

[0066] The specific operation steps of this invention can be as follows:

[0067] (1) Add chloroauric acid and reduced glutathione to 5-50 mL of deionized water at a molar ratio of 1:2-1:1, mix, and heat and stir at 60-80℃ for 12-24 hours. After the reaction is complete, use a dialysis bag with a molecular weight cutoff of 700-1500 Da and deionized water as the medium for dialysis treatment, collect the retained solution in the bag, and obtain the gold nanocluster solution.

[0068] (2) Dissolve the polyamine compound in deionized water and add it dropwise to the gold nanocluster solution described in step (1). After stirring until homogeneous, add 5-18 mM of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide aqueous solution to the mixture and continue stirring. Then add 10-36 mM of N-hydroxysuccinimide aqueous solution and react for 8-24 hours under stirring. The reaction product is dialyzed using a dialysis bag with a molecular weight cutoff of 700-1500 Da and deionized water as the dialysis medium. Collect the solution retained in the dialysis bag to obtain the amino-functionalized gold nanoclusters.

[0069] (3) The aqueous phase consists of the amino-functionalized gold nanoclusters solution and the polyvinyl alcohol solution described in step (2). The organic phase is a chloroform solution containing polylactic acid, isocyanate compounds and fluorescent conjugated molecules. The two phases are mixed in a volume ratio of 1:1 to 10:1, and then homogenized by ultrasonication to form an emulsion. The emulsion is then reacted for 12-24 hours to obtain a multicolored microsphere solution.

[0070] Preferably, the polyamine compound in step (2) is one or more of ethylenediamine, hexamethylenediamine, octyldiamine, p-xylenediamine, m-xylenediamine, and diethyltoluenediamine.

[0071] In step (2), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide act as coupling agents to convert the carboxyl groups in the gold nanoclusters into active ester groups, and then the ester groups react with the amino groups of the polyamine compound.

[0072] More preferably, the molar ratio of the polyamine compound to the gold nanoclusters in step (2) is 1:1 to 36:1.

[0073] More preferably, the isocyanate compound in step (3) is one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and hydrogenated phenylmethane diisocyanate.

[0074] More preferably, the conjugated molecule in step (3) is one or more of poly(9,9-dioctylfluorene), poly(9,9-dioctylfluorene-co-benzothiadiazole), poly(9,9-dioctylfluorene-co-dibenzothiophene-S,S-dioxide), poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole], poly3-hexylthiophene, and poly[2-methoxy-5-(2'-ethylhexoxy)-1,4-phenyleneethylene].

[0075] More preferably, in step (3), the mass fraction of the polyvinyl alcohol solution is 1-10%; the volume ratio of the amino-functionalized gold nanocluster solution to the polyvinyl alcohol solution is 15:1-30:1; the concentration of the isocyanate compound in the chloroform solution is 0.5-5 M; and the concentration of the fluorescent conjugated molecule in the chloroform solution is 1-5 M.

[0076] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0077] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0078] Unless otherwise specified, all materials and reagents described in the following examples are commercially available.

[0079] In the following embodiments, the fluorescence spectroscopy detection method, the CIE colorimetric determination method, and the experimental methods for testing the particle size of multicolor microspheres using a Malvern Zetasizer Nano ZS90 particle size analyzer are all conventional experimental methods well known to those skilled in the art. Where no specific conditions are specified in the experimental methods, they are usually operated according to conventional conditions.

[0080] Example 1

[0081] (1) Take 380 μL of chloroauric acid with a concentration of 253.917 mM (available from Shanghai Mairui Chemical Technology Co., Ltd.) and mix it with 48.106 mL of deionized water to obtain a diluted chloroauric acid solution. Take 46.1 mg of reduced glutathione (available from Shanghai Mairui Chemical Technology Co., Ltd.) and dissolve it in 1.5 mL of deionized water to prepare a solution, and add it to the above diluted chloroauric acid solution. Transfer the resulting mixed solution to a flask and place it in an oil bath. React at 70 °C and 500 rpm for 24 h. After the reaction is completed, dialyze the solution through a dialysis bag with a molecular weight cutoff of 1500 Da for 48 h. Collect the solution retained in the bag and concentrate it by rotary evaporation to obtain the gold nanocluster stock solution.

[0082] (2) Dissolve 207.75 mg of 1,8-diaminooctane (Shanghai Bid Pharmaceutical Technology Co., Ltd.) in 20 mL of deionized water, and add the solution dropwise to 50 mL of the gold nanocluster stock solution prepared in step (1). Mix and stir for 15 min. Dissolve 138 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (available from Shanghai Mairui Chemical Technology Co., Ltd.) in deionized water to prepare a solution, and add it to the above mixed solution. Continue stirring and react for 30 min. Then dissolve 166 mg of N-hydroxysuccinimide in 20 mL of deionized water to prepare a solution, and add it to the mixed solution. React under stirring conditions for 10 h. After the reaction is complete, dialyze the solution through a dialysis bag with a molecular weight cutoff of 1500 Da for two days, and collect the solution retained in the bag to obtain the amino-functionalized gold nanoclusters.

[0083] (3) 1350 μL of deionized water, 150 μL of the amino-functionalized gold nanocluster solution described in step (2), and 100 μL of polyvinyl alcohol solution (7.5% w / w, molecular weight 70000-90000 g / mol) (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) were mixed evenly to obtain 1.6 mL of aqueous phase mixture. The organic phase was 200 μL of chloroform solution, which contained 10 mg / mL of polylactic acid (molecular weight 85000-90000 g / mol, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 1 M of hexamethylene diisocyanate (available from Shanghai Merrill Chemical Technology Co., Ltd.), and 1 mg / mL of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] (molecular weight 10000-50000 g / mol). The organic phase was placed in the lower layer of a centrifuge tube, and the aqueous phase was placed in the upper layer. The mixture was homogenized for 1 min to form an oil-in-water emulsion. The reaction was then carried out for 12 hours. After centrifugation, the upper liquid layer was removed, and the lower solid layer was washed and dried to obtain multicolored microspheres.

[0084] Performance testing:

[0085] Figure 1 This is a high-resolution transmission electron micrograph of the amino-functionalized gold nanoclusters prepared in Example 1. According to... Figure 1 As can be seen, the size of the gold nanoclusters is around 3 nm, and the crystal striations of the gold nanoclusters are visible.

[0086] Figure 2 This is a transmission electron micrograph of the multicolor microspheres prepared by gold nanoclusters-assisted emulsion interfacial polymerization as described in Example 1. According to... Figure 2 As can be seen, the multicolored microspheres are irregular spherical shapes with a hollow structure.

[0087] Example 2

[0088] Steps (1)-(2) are the same as in Example 1;

[0089] (3) 1080 μL of deionized water, 120 μL of the amino-functionalized gold nanocluster solution described in step (2), and 80 μL of polyvinyl alcohol solution (7.5% w / w, molecular weight 70000-90000 g / mol) (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) were mixed thoroughly to obtain 1.28 mL of aqueous phase mixture. The organic phase was 200 μL of chloroform solution, containing 10 mg / mL of polylactic acid (molecular weight 85000-90000 g / mol, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 1 M of hexamethylene diisocyanate (available from Shanghai Merrill Chemical Technology Co., Ltd.), and 10 mg / mL of polylactic acid (molecular weight 85000-90000 g / mol, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.). -3 Poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] was prepared at concentrations ranging from mg / mL to 1 mg / mL. The organic phase was placed in the lower layer of a centrifuge tube, and the aqueous phase was placed in the upper layer. The mixture was homogenized for 1 min to form an oil-in-water emulsion. After reacting for 24 hours, the emulsion was centrifuged and the supernatant was removed. The lower solid layer was washed, dried, and then multicolored microspheres were obtained, which could emit various colors of light from orange to red.

[0090] Performance testing:

[0091] Figure 3 The fluorescence spectra of multicolor microspheres prepared by gold nanoclusters through emulsion-assisted interfacial polymerization in Example 2, with different concentrations of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] excited by 380 nm incident light, are shown. Figure 3 It is evident that as the concentration of the conjugated polymer material increases, the spectrum redshifts and becomes more intense.

[0092] Figure 4The image shows the CIE chromaticity diagrams of multicolor microspheres prepared by gold nanoclusters through emulsion-assisted interfacial polymerization in Example 2, with different concentrations of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] excited by 380 nm incident light. Figure 4 As can be seen, the emission color changes from orange to red as the concentration of the conjugated polymer material increases.

[0093] Figure 5 This presents the stability test results of multicolor microspheres prepared by gold nanoclusters-assisted emulsion interfacial polymerization in Example 2, after adding different concentrations of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] to the microspheres. The particle size of the multicolor microspheres was measured on days 3, 5, and 7 using a Malvern Zetasizer Nano ZS90 particle size analyzer. Figure 5 It is evident that the size of the multicolor microspheres remains relatively stable.

[0094] Example 3

[0095] (1) Take 3.8 mL of chloroauric acid with a concentration of 253.917 mM (available from Shanghai Mairui Chemical Technology Co., Ltd.) and mix it with 480.106 mL of deionized water to obtain a diluted chloroauric acid solution. Take 460.1 mg of reduced glutathione (available from Shanghai Mairui Chemical Technology Co., Ltd.) and dissolve it in 15 mL of deionized water to prepare a solution, and add it to the above diluted chloroauric acid solution. Transfer the resulting mixed solution to a flask, place it in an oil bath, and react it at 80 °C and 500 rpm for 20 h. After the reaction is completed, dialyze the solution through a dialysis bag with a molecular weight cutoff of 1500 Da for 48 h, collect the solution retained in the bag, and concentrate it by rotary evaporation to obtain the gold nanocluster stock solution.

[0096] (2) Dissolve 1668.04 mg of 1,6-hexanediamine (Shanghai Bid Pharmaceutical Technology Co., Ltd.) in 200 mL of deionized water. Add this solution dropwise to 500 mL of the gold nanocluster stock solution prepared in step (1). Mix and stir for 15 min. Dissolve 1.38 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (available from Shanghai Mairui Chemical Technology Co., Ltd.) in deionized water to prepare a solution. Add this solution to the above mixed solution and continue stirring for 30 min. Dissolve 1.66 g of N-hydroxysuccinimide in 200 mL of deionized water to prepare a solution. Add this solution to the mixed solution and react for 10 h under stirring. After the reaction is complete, dialyze the solution through a dialysis bag with a molecular weight cutoff of 1500 Da for two days. Collect the solution retained in the bag to obtain the amino-functionalized gold nanoclusters.

[0097] (3) 13.50 mL of deionized water, 1.5 mL of the amino-functionalized gold nanocluster solution described in step (2), and 1 mL of polyvinyl alcohol solution (7.5% w / w, molecular weight 70000-90000 g / mol) (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) were mixed thoroughly to obtain 16 mL of aqueous phase mixture. The organic phase was 2 mL of chloroform solution containing 10 mg / mL of polylactic acid (molecular weight 85000-90000 g / mol, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 1 M of toluene diisocyanate (available from Shanghai Merrill Chemical Technology Co., Ltd.), and 1 mg / mL to 10 mg / mL of other organic compounds. -3 Poly(9,9-dioctylfluorene-2,7-diyl) (molecular weight 50,000-300,000 g / mol) at different concentrations (mg / mL) were used. The organic phase was placed in the lower layer of a centrifuge tube, and the aqueous phase was placed in the upper layer. The mixture was homogenized for 1 min to form an oil-in-water emulsion. After reacting for 18 hours, the emulsion was centrifuged and the supernatant was removed. The lower solid layer was washed, dried, and then multicolored microspheres were obtained, which could emit blue, green, and red light.

[0098] Performance testing:

[0099] Figure 6 The fluorescence spectra of the gold cluster-based luminescent composite micromaterials prepared in Example 3, with different concentrations of poly(9,9-dioctylfluorene-2,7-diyl) added, are obtained under 380 nm incident light excitation. Figure 5 It is evident that the proportion of blue light emission increases with the increase of the concentration of conjugated polymer materials.

[0100] Figure 7 The image shows the CIE chromaticity diagrams of the gold cluster-based luminescent composite micromaterials prepared in Example 3, with different concentrations of poly(9,9-dioctylfluorene-2,7-diyl) added, under 380 nm incident light excitation. According to... Figure 6 As can be seen, the emission color changes from orange to blue as the concentration of the conjugated polymer material changes.

[0101] Figure 8 shows the stability test results of the gold cluster-based luminescent composite micromaterials prepared in Example 3 with different concentrations of poly(9,9-dioctylfluorene-2,7-diyl) added. The particle size of the multicolor microspheres was measured on days 3, 5, and 7 using a Malvern Zetasizer Nano ZS90 particle size analyzer. Figure 8 It is evident that the size of the multicolor microspheres remains relatively stable.

[0102] Example 4

[0103] (1) Take 190 μL of chloroauric acid with a concentration of 253.917 mM (available from Shanghai Mairui Chemical Technology Co., Ltd.) and mix it with 24.053 mL of deionized water to obtain a diluted chloroauric acid solution. Take 23.05 mg of reduced glutathione (available from Shanghai Mairui Chemical Technology Co., Ltd.) and dissolve it in 0.75 mL of deionized water to prepare a solution, and add it to the above diluted chloroauric acid solution. Transfer the resulting mixed solution to a flask, place it in an oil bath, and react it at 70℃ and 500 rpm for 24 h. After the reaction is completed, dialyze the solution through a dialysis bag with a molecular weight cutoff of 1500 Da for 48 h, collect the solution retained in the bag, and concentrate it by rotary evaporation to obtain the gold nanocluster stock solution.

[0104] (2) Dissolve 98.064 mg of p-xylenediamine (Shanghai Bid Pharmaceutical Technology Co., Ltd.) in 10 mL of deionized water, and add the solution dropwise to 25 mL of the gold nanocluster stock solution prepared in step (1). Mix and stir for 15 min. Separately, dissolve 69 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (available from Shanghai Mairui Chemical Technology Co., Ltd.) in deionized water to prepare a solution, and add it to the above mixed solution. Continue stirring and react for 30 min. Then, dissolve 83 mg of N-hydroxysuccinimide in 10 mL of deionized water to prepare a solution, and add it to the mixed solution. React under stirring conditions for 10 h. After the reaction is completed, dialyze the solution through a dialysis bag with a molecular weight cutoff of 1500 Da for two days, and collect the solution retained in the bag to obtain amino-functionalized gold nanoclusters.

[0105] (3) 675 μL of deionized water, 75 μL of the amino-functionalized gold nanocluster solution described in step (2), and 50 μL of polyvinyl alcohol solution (7.5% w / w, molecular weight 70000-90000 g / mol) (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) were mixed thoroughly to obtain 0.8 mL of aqueous phase mixture. The organic phase was 100 μL of chloroform solution containing 10 mg / mL of polylactic acid (molecular weight 85000-90000 g / mol, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 1 M of hydrogenated phenylmethane diisocyanate (available from Shanghai Merrill Chemical Technology Co., Ltd.), and 1 mg / mL to 10 mg / mL of other organic compounds. -3mg / mL poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)] (molecular weight 100,000-300,000 g / mol). The organic phase was placed in the lower layer of a centrifuge tube, and the aqueous phase was placed in the upper layer. The mixture was homogenized for 1 min to form an oil-in-water emulsion. The reaction was then carried out for 20 hours. After centrifugation, the upper liquid layer was removed, and the lower solid layer was washed, dried, and then multicolored microspheres were obtained, which could emit yellow to green light.

[0106] Figure 9 shows the stability test results of the gold cluster-based luminescent composite micromaterials prepared in Example 4 with different concentrations of poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)]. The particle size of the multicolor microspheres was measured on days 3, 5, and 7 using a Malvern Zetasizer Nano ZS90 particle size analyzer. As can be seen from Figure 9, the size of the multicolor microspheres is relatively stable.

[0107] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing multicolor microspheres by gold nanocluster-assisted emulsion interfacial polymerization, characterized in that, The method includes: (1) Chloroauric acid and reduced glutathione are mixed in an aqueous solution and reacted at 60-80℃. After the reaction is completed, the mixture is dialyzed to obtain a gold nanocluster solution. (2) Add polyamine compound, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to the gold nanocluster solution described in step (1), react, and perform dialysis after the reaction to obtain amino-functionalized gold nanocluster solution. (3) The aqueous phase includes: the aqueous solution obtained by mixing the amino-functionalized gold nanocluster solution and the polyvinyl alcohol solution in step (2), and the organic phase includes: the solution formed by dissolving isocyanate and fluorescent conjugated molecules in an organic solvent. The aqueous phase and the organic phase are mixed in a volume ratio of 1:1 to 10:1, homogenized to form an emulsion, and then reacted for 12-24 hours. The reaction solution is centrifuged, and the solid is washed and dried to obtain multicolor microspheres.

2. The method according to claim 1, characterized in that, In step (1), the molar ratio of chloroauric acid and reduced glutathione is 1:2-1:1; And / or, in step (1), the chemical reaction formula is: ； And / or, in step (1), the reaction time is 12-24 hours; And / or, in step (1), the dialysis process is as follows: the reaction product is dialyzed using a dialysis bag with a molecular weight cutoff of 700-1500 Da and deionized water as the dialysis medium, and the retained solution in the dialysis bag is collected to obtain the gold nanocluster solution.

3. The method according to claim 1, characterized in that, In step (2), the polyamine compound is selected from one or more of ethylenediamine, hexamethylenediamine, octyldiamine, p-xylenediamine, m-xylenediamine, and diethyltoluenediamine; And / or, in step (2), the molar ratio of the polyamine compound to the gold nanoclusters is 1:1-36:1; And / or, in step (2), the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to the gold nanoclusters is 200:1-100:1; And / or, in step (2), the molar ratio of the N-hydroxysuccinimide to the gold nanoclusters is 300:1-400:1; And / or, in step (2), the chemical reaction formula is: ； And / or, in step (2), the reaction temperature is room temperature; And / or, in step (2), the reaction time is 8-24 hours; And / or, in step (2), the dialysis treatment is performed as follows: the reaction product is dialyzed using a dialysis bag with a molecular weight cutoff of 700-1500 Da and deionized water as the dialysis medium, and the retained solution in the dialysis bag is collected to obtain the amino-functionalized gold nanocluster solution.

4. The method according to claim 1, characterized in that, In step (3), the isocyanate is selected from one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and hydrogenated phenylmethane diisocyanate; And / or, in step (3), the fluorescent conjugated molecule is selected from one or more of the following: poly(9,9-dioctylfluorene-2,7-diyl), poly(9,9-dioctylfluorene-co-dibenzothiophene-S,S-dioxide), poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole], poly3-hexylthiophene, poly[(9,9-di-n-octylfluorene-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)], and poly[2-methoxy-5-(2'-ethylhexoxy)-1,4-phenyleneethylene]. And / or, in step (3), the molecular weight of the polyvinyl alcohol is 70,000-90,000 g / mol; And / or, in step (3), the organic phase further includes polylactic acid; And / or, in step (3), the molecular weight of the polylactic acid is 85,000-90,000 g / mol; And / or, in step (3), the organic solvent includes: chloroform, dichloromethane, acetone.

5. The method according to claim 1, characterized in that, In step (3), the mass percentage of the polyvinyl alcohol solution is 1-10%; And / or, in step (3), the volume ratio of the amino-functionalized gold nanocluster solution to the polyvinyl alcohol solution is 15:1-30:1; And / or, in step (3), the concentration of the isocyanate compound in the organic phase solution is 0.5-5M; And / or, in step (3), the concentration of the fluorescent conjugated molecule in the organic phase solution is 1-5 M; And / or, in step (3), the concentration of polylactic acid in the organic phase solution is 0.1-1 mM; And / or, in step (3), the reaction utilizes the two-phase interface of the emulsion droplets of amino-functionalized gold nanoclusters as the reaction site, so that the functional amino groups of the amino-functionalized gold nanoclusters and the isocyanate monomers undergo a polymerization reaction at the two-phase interface, thereby obtaining the polyurea shell material of the multicolor microspheres, and the cavity of the multicolor microspheres is loaded with fluorescent conjugated molecules, thereby obtaining the multicolor microspheres. And / or, in step (3), the chemical reaction formula is: 。 6. The multicolor microspheres prepared by the method according to any one of claims 1-5.

7. The application of the multicolor microspheres according to claim 6 in the method for preparing photofunctional coatings.

8. A method for preparing a photofunctional coating, characterized in that, The method includes: coating a solution of the multicolor microspheres according to claim 6 onto a solid substrate and drying it to obtain the photofunctional coating.

9. The optically functional coating prepared by the method according to claim 8.

10. A composite material comprising the photofunctional coating according to claim 9.

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