Photonic crystal coating, preparation method and application thereof

Abstract

The present invention relates to a photonic crystal coating, a preparation method, and its application, belonging to the technical field of photonic crystal structure color generation. The photonic crystal coating comprises the following components, measured in parts by weight: 100 parts of a hard-core-soft-shell nanosphere dispersion, 1 to 8 parts of a leveling agent, 0.1 to 0.4 parts of a stray light absorber, and 0 to 6 parts of a high-boiling-point additive. The photonic crystal coating is directly prepared from hard-core-soft-shell colloidal nanospheres. The resulting structural color coating exhibits excellent structural stability (associated with high color fastness), high color saturation, and a significant iridescent effect.

Description

Technical Field

[0001] The invention relates to a photonic crystal coating, a preparation method and application thereof, and belongs to the technical field of photonic crystal structure color production. Background Art

[0002] Color plays a vital role in our daily lives, from household items to architectural decorations to traffic signs. Color not only enhances the visual beauty of an environment but also provides functional information.

[0003] Paint coloring is one of the primary methods for imparting color to objects. Paints typically consist of organic pigments (coloring components), film-forming components (binders or coating agents), and other auxiliary ingredients (such as leveling agents and thickeners). While organic pigments offer advantages such as strong tinting strength and hiding power, they often suffer from insufficient light fastness and environmental issues associated with chemical colorants. Photonic crystals are optical materials formed by a spatial periodic arrangement of materials with different refractive indices. Their fundamental characteristic is the presence of a photonic bandgap. When the photonic bandgap falls within the visible light range, visible light within the bandgap is prevented from propagating and selectively reflected. The resulting constructive interference stimulates the human eye, creating a visual effect of structural color. Photonic crystal structural color is a physical color typically characterized by high brightness, high saturation, an iridescent effect, and excellent light and environmental stability. Therefore, photonic crystals are excellent materials for coatings.

[0004] Chinese patent CN117004315A mixes a polymerizable liquid crystal monomer, a chain extender, an ultraviolet light initiator and a low-boiling point solvent and applies it to the surface of the substrate. It is cured under ultraviolet light, and the liquid crystal monomer and the chain extender self-assemble into a photonic crystal structural color coating. The structural color coating prepared by this method is bright in color and has strong structural stability. However, it can only be cured under ultraviolet light, and its application scenarios are relatively limited. Chinese patent CN118287357A introduces a cross-linking agent into the polymerization process of styrene (St) to obtain high-refractive index nano-microspheres, which are prepared into liquid photonic crystal coatings, applied to the surface of the substrate to construct a photonic crystal color-forming structure, and the photonic crystal structural color coating is obtained after polymer curing and encapsulation. This method has a simple preparation process and low cost. However, the encapsulating polymer will enter the interior of the PS photonic crystal, have a negative impact on the color of the coating, and the choice of encapsulating polymer is limited. Chinese patent CN116200125A coats a copper-tin alloy coating on the surface of a substrate, and then coats a photonic crystal layer with a columnar pore structure and a thin-film interference layer composed of multiple thin films with different refractive indices on the surface of the copper-tin alloy coating to enhance the optical properties of the coating. Finally, a covering layer made of a thermoplastic polymer material is coated on the surface of the photonic crystal layer and the thin-film interference layer to provide the mechanical strength of the coating. This method can form two reflective effects by providing a photonic crystal layer and a thin-film interference layer. However, the preparation process is relatively complex and the cost is high, which is not conducive to widespread application. Chinese invention patent CN116656169A first coats a ceramic precursor on an opal-structured photonic crystal, sinters the ceramic material at high temperature, and removes the polymer opal template to obtain an inverse opal photonic crystal. The inverse opal photonic crystal is then crushed to obtain an inverse opal-structured photonic crystal pigment powder, which is finally mixed with a film-forming substance and auxiliary components to obtain a photonic crystal coating. The photonic crystal coating prepared by this method has rich colors and metallic luster, but the preparation process is complex and energy consumption is high.

[0005] Therefore, a photonic crystal coating with simple preparation process, low cost and bright structural color is invented, which has very important practical application value. Summary of the Invention

[0006] The purpose of the present invention is to provide a photonic crystal coating, which is directly prepared from hard-core-soft-shell colloidal nanospheres. The structural color coating prepared by the coating has excellent structural stability, high saturation of structural color, good color fastness, and exhibits a significant iridescent effect.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A photonic crystal coating, comprising the following components in parts by weight: 100 parts of a hard-core-soft-shell nanosphere dispersion, 1 to 8 parts of a leveling agent, 0.1 to 0.4 parts of a stray light absorber, and 0 to 6 parts of a high boiling point additive;

[0009] The hard-core-soft-shell nanospheres have a core composed of one of highly cross-linked polystyrene (PS), polymethyl methacrylate (PMMA), polymethacrylic acid (PMAA), poly(styrene-methyl methacrylate) (P(St-MMA)) or poly(styrene-methacrylic acid) (P(St-MAA)).

[0010] The shell layer is one of the soft and hard monomer copolymers of poly(butyl acrylate-methyl methacrylate) (P(MMA-BA)), poly(hydroxyethyl acrylate-hydroxyethyl methacrylate) (P(HEA-HEMA)), poly(ethyl acrylate-methacrylic acid) (P(EA-MAA)), poly(isobutyl acrylate-methyl methacrylate) (P(MMA-IBA)), poly(tert-butyl acrylate-methyl methacrylate) (P(MMA-TBA)), or poly(isooctyl acrylate-methyl methacrylate) (P(MMA-2-EHA));

[0011] The weight ratio of the soft shell to the hard core is 1:0.5~1.5; the weight ratio of the soft monomer to the hard monomer in the soft shell is 1:0.5~2.

[0012] Preferably, the hard-core-soft-shell nanospheres have a diameter of 150-350 nm, good sphericity, and a monodispersity of less than 0.12.

[0013] Preferably, the content of nanospheres in the hard-core-soft-shell nanosphere dispersion is 15-50 wt %, with the balance being water.

[0014] Preferably, the photonic crystal coating comprises the following components in parts by weight:

[0015] 100 parts of 30-50wt% hard-core-soft-shell nanosphere dispersion, 1-8 parts of leveling agent, 0.1-0.4 parts of black pigment, 0-6 parts of high boiling point additive; or

[0016] 100 parts of a hard-core-soft-shell nanosphere dispersion with a mass fraction of 15-30 wt%, 1-8 parts of a leveling agent, 0.1-0.4 parts of a black pigment, and 2-6 parts of a high boiling point additive.

[0017] Preferably, the leveling agent is one or a mixture of fatty alcohol polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, fatty acid polyoxyethylene ester, fatty acid methyl ester ethoxylate or polypropylene glycol ethylene oxide adduct;

[0018] The stray light absorber is one or a mixture of carbon black, water-soluble or water-dispersible black pigment;

[0019] The high boiling point auxiliary agent is selected from one or a mixture of glycerol, propylene glycol, formamide or ethylene glycol.

[0020] A method for preparing the photonic crystal coating comprises the following steps: placing 100 parts by weight of a hard-core-soft-shell nanosphere dispersion, 1 to 8 parts by weight of a leveling agent, 0.1 to 0.4 parts by weight of a stray light absorber, and 0 to 6 parts by weight of a high boiling point additive into a container, and stirring the mixture thoroughly to obtain the photonic crystal coating.

[0021] A photonic crystal structural color coating is prepared by coating the photonic crystal coating.

[0022] A method for preparing a photonic crystal structured color coating, the method comprising the following steps:

[0023] S1. Coating: applying the photonic crystal coating evenly on the surface of the substrate;

[0024] S2. Heating assembly: The substrate coated in S1 is heated and assembled to evaporate the water inside the photonic crystal, inducing the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating; the heating assembly conditions are 50-95°C and 5-40 min;

[0025] For photonic crystal coatings made from hard-core-soft-shell nanospheres with a weight ratio of soft monomer to hard monomer of 1:0.5-1 in the soft shell, a second assembly process is required to further improve the regularity of the photonic crystal structure and obtain a photonic crystal structure-color coating with bright colors and significant iridescent effects. The secondary assembly conditions are 110-140°C for 2-10 minutes.

[0026] S3. Encapsulation: Apply an encapsulation polymer to the surface of the photonic crystal structural color coating obtained in S2 and heat-treat it to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect; the heating treatment conditions are drying at a temperature of 50-100°C for 5-40 minutes and baking at 110-140°C for 2-10 minutes.

[0027] Preferably, the substrate in S1 is textile, wood, steel, plastic, paper or glass.

[0028] Preferably, the application method described in S1 is a scraping method or a spraying method.

[0029] Preferably, when the blade coating method is selected in S1, the following components are prepared, based on the weight of the photonic crystal coating: 100 parts of a 30-50 wt% hard-core-soft-shell nanosphere dispersion, 1-8 parts of a leveling agent, 0.1-0.4 parts of a black pigment, and 0-6 parts of a high-boiling-point additive. The concentration of the hard-core-soft-shell nanosphere dispersion is preferably 40-45 wt%.

[0030] Preferably, when spraying is selected as the application method in S1, the following components are added, based on the weight of the photonic crystal coating: 100 parts of a 15-30 wt% hard-core-soft-shell nanosphere dispersion, 1-8 parts of a leveling agent, 0.1-0.4 parts of a black pigment, and 2-6 parts of a high-boiling-point additive. The concentration of the hard-core-soft-shell nanosphere dispersion is preferably 20-25 wt%.

[0031] Preferably, when the application method selected in S1 is the scraping method, the paint is evenly applied using a putty knife, a wire rod, a roller, a brush, or the like in a shear-induced manner.

[0032] Preferably, when the application method selected in S1 is spraying, the tool used is a gravity-feed, suction-feed, pressure-feed, or pump-feed spray gun.

[0033] Preferably, the encapsulating polymer in S4 is water-based polyurethane or water-based polyacrylate.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. This method breaks through the conventional process of preparing photonic crystal pigments from nanospheres, and then preparing photonic crystal coatings from photonic crystal pigments. Instead, it adopts a new method of directly constructing a photonic crystal coating system from colloidal nanospheres, which is simple and has low energy consumption.

[0036] 2. The present invention utilizes hard-core-soft-shell nanoparticles with a refractive index difference as assembly elements. After assembly, they form a non-close-packed photonic crystal with a hard core as the skeleton and a soft shell as the continuous phase. The microparticles contain their own adhesive components, eliminating the need for additional adhesive or film-forming components in the coating system, resulting in a system with excellent stability and strong tolerance.

[0037] 3. The constructed structural color coating has the characteristics of high structural stability (high color fastness) and high color saturation, and has a significant iridescent effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a digital photo of the photonic crystal coating (left) and structural color coating (right) prepared in Example 1 with a soft-hard monomer weight ratio of 1:0.57;

[0039] Figure 2These are digital photos of the photonic crystal coating (left) and structural color coating (right) prepared using P MAA@P(MMA-BA) nanospheres in Example 2;

[0040] Figure 3 This is the reflectivity curve of the structural color coating prepared by the doctor blade coating method with a nanosphere concentration of 45 wt% in Example 3;

[0041] Figure 4 A digital photograph (left) and a reflectivity curve (right) of a structural color coating prepared by spraying with a nanosphere concentration of 25 wt% in Example 4 are shown;

[0042] Figure 5 This is a digital photo of the structural color coating with nano-microspheres having a particle size of 230 nm in Example 5;

[0043] Figure 6 This is a digital photo of the structural color coating prepared by secondary assembly at 130° C. for 5 minutes in Example 6;

[0044] Figure 7 This is a digital photo of the photonic crystal coating prepared in Comparative Example 1 with a weight ratio of soft and hard monomers of 1:0.2;

[0045] Figure 8 This is a digital photo of the structural color coating prepared in Comparative Example 2 with a soft and hard monomer weight ratio of 1:3;

[0046] Figure 9 This is a digital photo of the structural color coating prepared using PS@PMMA nanospheres in Comparative Example 3;

[0047] Figure 10 This is the reflectivity curve of the structural color coating prepared by the blade coating method in Comparative Example 4 with a nanosphere concentration of 10 wt%;

[0048] Figure 11 The digital photo (left) and reflectivity curve (right) of the structural color coating prepared by spraying with a nanosphere concentration of 45 wt% in Comparative Example 5 are shown;

[0049] Figure 12 This is a digital photograph of the structural color coating prepared in Example 5 after secondary assembly at 150° C. for 2 minutes. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described in detail below through specific examples. It should be understood that the implementation of the present invention is not limited to the following examples, and any form of modification and / or change made to the present invention will fall within the scope of protection of the present invention.

[0051] In the present invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. The methods in the following examples are all conventional methods in the art unless otherwise specified.

[0052] Unless otherwise specified, the reagents used in the following examples can be purchased from conventional biochemical reagent stores.

[0053] In the present invention, nano-microspheres with a hard core-soft shell structure are prepared according to the Chinese invention patent "A method for preparing flexible photonic crystal elementary nano-microspheres" (ZL201911112794.X, CN110804127B).

[0054] Example 1

[0055] A photonic crystal coating was prepared by mixing 20g of a 45wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 260nm, 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.048g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The shell / core monomer weight ratio of the PS@P(MMA-BA) nanospheres was 1:0.63, and the shell soft / hard monomer weight ratio was 1:0.57.

[0056] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0057] S1. Coating: The photonic crystal coating prepared by the above method is evenly coated on the surface of the PPS plastic substrate through a wire rod;

[0058] S2. Heating assembly: The coated PPS plastic substrate is placed in an 80°C oven for 15 minutes to evaporate the water inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating;

[0059] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 140°C oven for secondary assembly for 2 minutes to further improve the regularity of the photonic crystal structure and obtain a structural color coating with beautiful colors and significant iridescent effect;

[0060] S4. Packaging: Spray water-based polyurethane on the surface of the secondary assembled structural color coating and dry it at 80°C for 15 minutes and bake it at 140°C for 2 minutes to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect.

[0061] Example 2 A photonic crystal coating

[0062] A photonic crystal coating was prepared by mixing 20g of a 45wt% PMAA@P(MMA-BA) nanosphere dispersion with a particle size of 252nm, 1.0g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.052g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PMAA@P(MMA-BA) nanospheres had a shell / core monomer weight ratio of 1:0.8 and a shell soft / hard monomer weight ratio of 1:0.57.

[0063] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0064] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the PPS plastic substrate by a roller;

[0065] S2. Heating assembly: The coated PPS plastic substrate is placed in a 90°C oven for heating assembly for 10 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating;

[0066] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 110°C oven for secondary assembly for 10 minutes to further improve the regularity of the photonic crystal structure and obtain a structural color coating with beautiful colors and significant iridescent effect;

[0067] S4. Packaging: Spray water-based polyurethane on the surface of the secondary assembled structural color coating and dry it at 90°C for 10 minutes and bake it at 110°C for 10 minutes to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect.

[0068] Example 3 A photonic crystal coating

[0069] A photonic crystal coating was prepared by mixing 20g of a 45wt% dispersion of PS@P(EA-MMA) nanospheres with a particle size of 252nm, 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.052g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@P(EA-MMA) nanospheres had a shell / core monomer weight ratio of 1:1 and a shell soft / hard monomer weight ratio of 1:1.5.

[0070] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0071] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the metal substrate by a brush;

[0072] S2. Heating assembly: The coated plastic substrate is placed in a 90°C oven for heating assembly for 10 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating;

[0073] S3. Packaging: Spray water-based polyurethane on the surface of the heated and assembled structural color coating and dry it at 90°C for 10 minutes and bake it at 110°C for 10 minutes to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect.

[0074] Example 4

[0075] A photonic crystal coating was prepared by mixing 20g of a 25wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 265nm, along with 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, 0.048g of carbon black, and 0.8g of glycerol. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@P(MMA-BA) nanospheres had a shell / core monomer weight ratio of 1:1, and a shell soft / hard monomer weight ratio of 1:0.57.

[0076] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0077] S1. Coating: The photonic crystal coating obtained by the above method is sprayed on the surface of the PPS plastic substrate by a pump-type spray gun;

[0078] S2. Heating assembly: The coated PPS plastic substrate is placed in an 80°C oven for 15 minutes to evaporate the water inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating;

[0079] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 140°C oven for secondary assembly for 2 minutes to further improve the regularity of the photonic crystal structure and obtain a structural color coating with beautiful colors and significant iridescent effect;

[0080] S4. Packaging: Spray water-based polyurethane on the surface of the secondary assembled structural color coating and dry it at 80°C for 15 minutes and bake it at 140°C for 2 minutes to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect.

[0081] Example 5

[0082] A photonic crystal coating was prepared by mixing 20g of a 25wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 230nm, along with 1.6g of a fatty alcohol polyoxyethylene ether leveling agent, 0.030g of carbon black, and 0.6g of glycerol. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@P(MMA-BA) nanospheres had a shell / core monomer weight ratio of 1:0.5 and a shell soft / hard monomer weight ratio of 1:1.3.

[0083] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0084] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the metal substrate by a pump-type spray gun;

[0085] S2. Heating assembly: The coated plastic substrate is placed in a 60°C oven for heating assembly for 30 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating;

[0086] S3. Packaging: Spray water-based polyurethane on the surface of the secondary assembled structural color coating and dry it at 60°C for 30 minutes and bake it at 110°C for 10 minutes to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect.

[0087] Example 6

[0088] A photonic crystal coating was prepared by mixing 20g of a 50wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 260nm, 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.048g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The shell / core monomer weight ratio of the PS@P(MMA-BA) nanospheres was 1:0.8, and the shell soft / hard monomer weight ratio was 1:0.57.

[0089] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0090] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the wooden substrate by a brush;

[0091] S2. Heating assembly: The coated plastic substrate is placed in a 70°C oven for 20 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating;

[0092] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 130°C oven for secondary assembly for 5 minutes to further improve the regularity of the photonic crystal structure and obtain a structural color coating with beautiful colors and significant iridescent effect;

[0093] S4. Packaging: Spray water-based polyurethane on the surface of the secondary assembled structural color coating and dry it at 70°C for 20 minutes and bake it at 130°C for 5 minutes to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect.

[0094] Comparative Example 1

[0095] A photonic crystal coating was prepared by mixing 20g of a 45wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 260nm, along with 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, 0.048g of carbon black, and 0.8g of glycerol. The mixture was stirred with a magnetic stirrer until uniformly mixed. The shell / core monomer weight ratio of the PS@P(MMA-BA) nanospheres was 1:0.63, and the shell soft / hard monomer weight ratio was 1:0.2.

[0096] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0097] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the PPS plastic substrate through a wire rod;

[0098] S2. Heating assembly: The coated PPS plastic substrate is placed in an 80°C oven for 15 minutes to evaporate the water inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating;

[0099] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 140°C oven for secondary assembly for 2 minutes to further improve the regularity of the photonic crystal structure and obtain a structural color coating with lower color saturation and no red color effect;

[0100] Comparative Example 2

[0101] A photonic crystal coating was prepared by mixing 20g of a 45wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 260nm, 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.048g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@P(MMA-BA) nanospheres had a shell / core monomer weight ratio of 1:0.63, and a shell soft / hard monomer weight ratio of 1:3.

[0102] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0103] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the PPS plastic substrate through a wire rod;

[0104] S2. Heating assembly: The PPS-coated plastic substrate is placed in an 80°C oven for 15 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating.

[0105] Comparative Example 3

[0106] A photonic crystal coating was prepared by mixing 20g of a 45wt% dispersion of PS@PMMA nanospheres with a particle size of 252nm, 1.0g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.052g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@PMMA nanospheres had a shell / core monomer weight ratio of 1:0.8 and a shell soft / hard monomer weight ratio of 1:0.57.

[0107] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0108] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the PPS plastic substrate by a roller;

[0109] S2. Heating assembly: The coated PPS plastic substrate is placed in a 90°C oven for heating assembly for 10 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating.

[0110] Comparative Example 4

[0111] A photonic crystal coating was prepared by mixing 20g of a 10wt% dispersion of PS@P(EA-MMA) nanospheres with a particle size of 210nm, 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, and 0.052g of carbon black. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@P(EA-MMA) nanospheres had a shell / core monomer weight ratio of 1:1 and a shell soft / hard monomer weight ratio of 1:1.5.

[0112] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0113] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the PPS plastic substrate through a wire rod;

[0114] S2. Heating assembly: The coated PPS plastic substrate is placed in a 90°C oven for heating assembly for 10 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating;

[0115] S3. Packaging: spray water-based polyurethane on the surface of the heated assembled structural color coating and dry it at 90°C for 10 minutes and bake it at 110°C for 10 minutes to further stabilize and solidify the photonic crystal layer to obtain the structural color coating.

[0116] Comparative Example 5

[0117] A photonic crystal coating was prepared by mixing 20g of a 45wt% dispersion of PS@P(MMA-BA) nanospheres with a particle size of 265nm, along with 0.8g of a fatty alcohol polyoxyethylene ether leveling agent, 0.048g of carbon black, and 0.8g of glycerol. The mixture was stirred with a magnetic stirrer until uniformly mixed. The PS@P(MMA-BA) nanospheres had a shell / core monomer weight ratio of 1:1 and a shell soft / hard monomer weight ratio of 1:0.57.

[0118] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0119] S1. Coating: The photonic crystal coating obtained by the above method is sprayed on the surface of the PPS plastic substrate by a pump-type spray gun;

[0120] S2. Heating assembly: The coated PPS plastic substrate is placed in an 80°C oven for 15 minutes to evaporate the water inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating;

[0121] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 140°C oven for secondary assembly for 2 minutes to further improve the regularity of the photonic crystal structure and obtain a darker color of the structural color coating.

[0122] Comparative Example 6

[0123] 20 g of PS@P(MMA-BA) nanosphere dispersion with a particle size of 260 nm and a mass fraction of 50 wt%, 0.8 g of fatty alcohol polyoxyethylene ether leveling agent, and 0.048 g of carbon black were mixed and stirred with a magnetic stirrer to obtain a photonic crystal coating.

[0124] In PS@P(MMA-BA) nanospheres, the shell / core monomer weight ratio is 1:0.8, and the shell soft / hard monomer weight ratio is 1:0.57.

[0125] The photonic crystal coating obtained by the above method is used to prepare a photonic crystal structure color coating, and the method is as follows:

[0126] S1. Coating: The photonic crystal coating obtained by the above method is evenly coated on the surface of the metal substrate by a brush;

[0127] S2. Heating assembly: The coated plastic substrate is placed in a 70°C oven for 20 minutes to evaporate the moisture inside the photonic crystal and induce the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structured color coating;

[0128] S3. Secondary assembly: The heated assembled photonic crystal structural color coating is placed in a 150°C oven for secondary assembly for 2 minutes, in the hope of further improving the regularity of the photonic crystal structure, but the color of the structural color coating is damaged.

[0129] The digital photos of the photonic crystal coating and structural color coating constructed in Example 1 are shown in Figure 1 The photonic crystal coating has high brightness, and the prepared structural color coating has beautiful color and significant iridescent effect, indicating that the photonic crystal coating can effectively construct a structural color coating on a plastic substrate by coating.

[0130] The digital photos and SEM images of the structural color coating constructed in Example 2 are shown in Figure 2 As shown in the figure, the photonic crystals assembled by nanospheres have excellent structural regularity and beautiful colors.

[0131] The reflectivity curve of the structural color coating constructed in Example 3 is shown in FIG. Figure 3 ,As shown in the figure, the reflection peak at 45wt% concentration is high and narrow, ,indicating that the brightness and saturation of its structural color are high.

[0132] The optical properties of the structural color coating constructed in Example 4 are shown in Figure 4 As shown in the figure, the reflection peak at a concentration of 25wt% is high and narrow, the coating color is bright, and the structural color has high brightness and saturation.

[0133] The digital photo of the structural color coating constructed in Example 5 is shown in Figure 5 The structural color coating has bright colors and a significant iridescent effect, indicating that the photonic crystal coating can effectively construct a structural color coating on a metal substrate by spraying.

[0134] The digital photo of the structural color coating constructed in Example 6 is shown in Figure 6 The structural color coating has bright colors and significant iridescent effects, indicating that the photonic crystal coating can be used to construct a structural color coating on a wood substrate by brushing.

[0135] The structural color coating prepared in Comparative Example 1 is shown in the digital photo. Figure 7Compared with Example 1, the proportion of hard monomer in the shell layer of Comparative Example 1 is too low, and the prepared structural color coating is dull in color and has no iridescent effect.

[0136] The structural color coating prepared in Comparative Example 2 is shown in the digital photo. Figure 8 Compared with Example 1, the proportion of hard monomer in the shell layer of Comparative Example 2 is too high, the prepared structural color coating cannot form a film, and the structural stability is poor.

[0137] The structural color coating prepared in Comparative Example 3 is shown in FIG. Figure 9 Compared with Example 2, the microsphere shell layer of Comparative Example 3 only has a hard monomer. When preparing the coating, the structural color coating is broken and the structural stability is poor.

[0138] The structural color coating prepared in Comparative Example 4 is shown in FIG. Figure 10 Compared with Example 3, when the structural color coating was prepared by the blade coating method in Comparative Example 4, the concentration of nanospheres was too low (10 wt %), and the reflectivity of the prepared structural color coating was low, and the color saturation and brightness were poor.

[0139] The structural color coating prepared in Comparative Example 5 is shown in FIG. Figure 11 Compared with Example 4, when the structural color coating was prepared by spraying in Comparative Example 5, the concentration of nano-microspheres was too high (45 wt %), and the uniformity of the spraying was poor. Moreover, since there was less water in the spray droplets and more microspheres, the microspheres did not have enough time to arrange themselves regularly. As a result, the reflectivity of the prepared structural color coating was low, and the color saturation and brightness were poor.

[0140] The structural color coating prepared in Comparative Example 6 is shown in FIG. Figure 12 Compared with Example 6, in Comparative Example 6, the assembly temperature was too high during the secondary assembly, and the color of the prepared structural color coating was dark.

[0141] In summary, the core of this invention lies in the uniform mixing of a hard-core-soft-shell nanosphere dispersion with a leveling agent, a stray light absorber, and a high-boiling-point additive to produce a photonic crystal coating. This coating system exhibits excellent film-forming ability. Through coating, drying, baking, and encapsulation processes, photonic crystal structural color coatings can be easily and conveniently prepared over large areas. This method is simple and applicable to a wide range of substrates. The resulting structural color coating combines high structural stability (high color fastness) with high color saturation, exhibiting a significant iridescent effect.

[0142] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0143] The above is a detailed introduction to a photonic crystal coating, a preparation method, and its application provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A photonic crystal coating, characterized in that The photonic crystal coating comprises the following components in parts by weight: 100 parts of a hard-core-soft-shell nanosphere dispersion, 1 to 8 parts of a leveling agent, 0.1 to 0.4 parts of a stray light absorber, and 0 to 6 parts of a high boiling point additive; The hard-core-soft-shell nanospheres have a core composed of one of highly cross-linked polystyrene (PS), polymethyl methacrylate (PMMA), polymethacrylic acid (PMAA), poly(styrene-methyl methacrylate) (P(St-MMA)) or poly(styrene-methacrylic acid) (P(St-MAA)). The shell layer is one of the soft and hard monomer copolymers of poly(butyl acrylate-methyl methacrylate) (P(MMA-BA)), poly(hydroxyethyl acrylate-hydroxyethyl methacrylate) (P(HEA-HEMA)), poly(ethyl acrylate-methacrylic acid) (P(EA-MAA)), poly(isobutyl acrylate-methyl methacrylate) (P(MMA-IBA)), poly(tert-butyl acrylate-methyl methacrylate) (P(MMA-TBA)), or poly(isooctyl acrylate-methyl methacrylate) (P(MMA-2-EHA)); The weight ratio of the soft shell to the hard core is 1:0.5~1.5; the weight ratio of the soft monomer to the hard monomer in the soft shell is 1:0.5~2.

2. The photonic crystal coating according to claim 1, characterized in that: The hard-core-soft-shell nanospheres have a diameter of 150-350 nm, good sphericity, and a monodispersity of less than 0.

12.

3. The photonic crystal coating according to claim 1, wherein: The content of nanospheres in the hard-core-soft-shell nanosphere dispersion is 15-50 wt %, with the balance being water.

4. The photonic crystal coating according to claim 1, wherein: The photonic crystal coating comprises the following components in parts by weight: 100 parts of 30-50wt% hard-core-soft-shell nanosphere dispersion, 1-8 parts of leveling agent, 0.1-0.4 parts of black pigment, 0-6 parts of high boiling point additive; or 100 parts of hard-core-soft-shell nanosphere dispersion with a mass fraction of 15-30wt%, 1-8 parts of leveling agent, 0.1-0.4 parts of black pigment, and 2-6 parts of high boiling point additive.

5. The photonic crystal coating according to claim 1, characterized in that: The leveling agent is one or a mixture of fatty alcohol polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, fatty acid polyoxyethylene ester, fatty acid methyl ester ethoxylate or polypropylene glycol ethylene oxide adduct; The stray light absorber is one or a mixture of carbon black, water-soluble or water-dispersible black pigment; The high boiling point auxiliary agent is selected from one or a mixture of glycerol, propylene glycol, formamide or ethylene glycol.

6. A method for preparing the photonic crystal coating according to claim 1, characterized in that The method comprises the following steps: placing 100 parts by weight of a hard-core-soft-shell nano-microsphere dispersion, 1 to 8 parts of a leveling agent, 0.1 to 0.4 parts of a stray light absorber, and 0 to 6 parts of a high boiling point additive into a container, and fully stirring the mixture to obtain a photonic crystal coating.

7. A photonic crystal structure color coating, characterized in that: The photonic crystal structural color coating is prepared by coating the photonic crystal coating according to claim 1.

8. A method for preparing a photonic crystal structure color coating, characterized in that The method comprises the following steps: S1. Coating: uniformly applying the photonic crystal coating according to claim 1 on the surface of the substrate; S2. Heating assembly: The substrate coated in S1 is heated and assembled to evaporate the water inside the photonic crystal, inducing the microspheres to move toward a highly regular arrangement structure, thereby obtaining a photonic crystal structural color coating; the heating assembly conditions are 50-95°C and 5-40 min; For photonic crystal coatings made from hard-core-soft-shell nanospheres with a weight ratio of soft monomer to hard monomer of 1:0.5-1 in the soft shell, a second assembly process is required to further improve the regularity of the photonic crystal structure and obtain a photonic crystal structure-color coating with bright colors and significant iridescent effects. The secondary assembly conditions are 110-140°C for 2-10 minutes. S3. Encapsulation: Apply an encapsulation polymer to the surface of the photonic crystal structural color coating obtained in S2 and heat-treat it to further stabilize and solidify the photonic crystal layer, thereby obtaining a structural color coating with high color fastness and significant iridescent effect; the heating treatment conditions are drying at a temperature of 50-100°C for 5-40 minutes and baking at 110-140°C for 2-10 minutes.

9. The method for preparing a photonic crystal structured color coating according to claim 8, characterized in that: The substrate in S1 is textile, wood, steel, plastic, paper or glass.

10. The method for preparing a photonic crystal structured color coating according to claim 8, characterized in that: The application method described in S1 is a knife coating method or a spray coating method.

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