CN114507016A

CN114507016A - Preparation method and application of photonic crystal

Info

Publication number: CN114507016A
Application number: CN202210212961.3A
Authority: CN
Inventors: 程群峰; 杨田田
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2022-03-04
Filing date: 2022-03-04
Publication date: 2022-05-17
Anticipated expiration: 2042-03-04
Also published as: CN114507016B

Abstract

The invention discloses a preparation method and application of a photonic crystal. The method is characterized in that the micron/nano particles and the polymer and/or the small-particle-size nano particles are prepared by a co-assembly method. The preparation method adopts a vertical sedimentation method, a blade coating method, a spin coating method, a roll coating method, a spray coating method, a dripping coating method, a film fishing method and the like. The polymer comprises starch, chitosan, cellulose, lignin, polylactic acid, resin, polyacrylic acid, polyimide, protein and derivatives thereof and the like. The photonic crystal prepared by the invention has good photonic band gap and self-supporting property, and has important application prospects in the aspects of high-performance photoelectric devices, catalysis, colorful packaging and the like.

Description

Preparation method and application of photonic crystal

Technical Field

The invention relates to a preparation method and application of a photonic crystal, which is a method for assembling the photonic crystal by utilizing the entropy-induced ordering principle and belongs to the field of preparation and application of photonic crystal materials.

Background

The photonic crystal has good optical regulation performance and has wide application prospect in the fields of photoelectric devices, detection and analysis, catalysis, energy storage, food, intelligent packaging and the like. The colloid self-assembly is a common method for preparing the photonic crystal, and has the advantages of simple operation, low cost and the like. However, the currently used colloid self-assembly method is realized based on self-assembly of nanoparticles at a 'gas-liquid' interface, and the photonic crystal colloid ball obtained by assembly has poor adhesion with a substrate and low mechanical strength, and is difficult to avoid cracks in the drying process. A paper (nat. commun.2016,7,11661.) reports a method for achieving large-area assembly of colloidal particles using bending, oscillating shear-inducing techniques. The paper (adv. funct. mater.2021,31,2010746) proposes a method of constructing photonic crystals on large area fabrics using pre-crystallized liquid colloidal crystals. In addition, many researches are dedicated to solve the problems of crack generation (j. phys. chem.c,2011,115, 9970-. Therefore, it is important to develop a general preparation method and application of the photonic crystal which is simple, low in cost, suitable for preparing good mechanical properties and stability and free of cracks.

Disclosure of Invention

In view of the problems of the existing photonic crystal preparation methods, the invention provides a preparation method and application of a photonic crystal. The method is a method for assembling photonic crystals by utilizing the entropy-induced ordering principle, and the photonic crystals are prepared by utilizing the entropy-induced ordering assembly of nano particles under the emptying effect; on the other hand, a way for realizing the preparation of the large-area photonic crystal by using the method is provided.

The inventor has long-term research and surprisingly found that the method for preparing the photonic crystal through entropy-induced ordered assembly has uniform color and no crack, and realizes the large-area preparation of the photonic crystal. The method for preparing the photonic crystal has simple process and easy implementation, and can realize the preparation of the full-color photonic crystal.

Entropy represents the number of microscopic states of the system. In free space, the micron/nano particles are randomly and disorderly distributed, the free space of each other is not limited, and the entropy of the system is maximum; under a limited space, the free volumes of the micro/nano particles are overlapped, the micro/nano particles tend to be regularly and orderly arranged, so that the free volumes of all the micro/nano particles tend to be consistent, the entropy of a system is maximized, and the system is most stable.

The object of the invention is thus achieved.

A preparation method of photonic crystals comprises the following steps: (1) a first micro/nanoparticle; and (2) a polymer and/or at least one second nanoparticle; mixing the raw materials to form a mixture, and then preparing the photonic crystal by a co-assembly method; wherein, micron/nano-particles refer to micron-sized particles or nano-sized particles, and the particle size of the first micron/nano-particles is larger than that of the second nano-particles.

In the present invention, micro/nano particles refer to micro-sized particles or nano-sized particles.

Further, in the system of mixing the first micron/nanoparticle with the polymer and/or the second nanoparticle, when the concentration of the polymer and/or the second nanoparticle in the system is increased or the space for solvent evaporation is limited, the volume fraction of the micron/nanoparticle is increased, and the micron/nanoparticle are aggregated with each other under the evacuation effect to form a regular ordered structure, so that the entropy of the system tends to be maximized, and a stable state with the lowest energy is achieved; wherein entropy represents the number of microscopic states of the system.

Further, the concentration of the first micro/nanoparticles in the mixture is 0.001 wt% to 75 wt%, preferably 0.005 to 65 wt%, more preferably 0.01 to 60 wt%. For example, the concentration of the first micro/nanoparticles is 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 25 wt%, 26 wt%, 3 wt%, 1 wt%, 30 wt%, 25 wt%, 1 wt%, 25 wt%, 1 wt%, 25 wt%, 30 wt%, 25 wt%, 30 wt%, 25 wt%, 40 wt%, of the total, 1 wt%, 40 wt%, 25 wt%, 40 wt%, 25 wt%, 40 wt%, 1 wt%, 40 wt%, 1 wt%, 40 wt%, 25 wt%, 40 wt%, 25 wt%, 40 wt%, 25 wt%, 1 wt%, 25 wt%, 40 wt%, 25 wt%, 40 wt%, of the total, 25 wt%, 40 wt%, 25 wt%, 40 wt%, 25 wt%, 40 wt%, 1 wt%, 40 wt%, 25 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, 65 wt%, 66 wt%, 67 wt%, 68 wt%, 69 wt%, 70 wt%, 71 wt%, 72 wt%, 73 wt%, 74 wt%, or 75 wt%.

Further, the polymer is added in an amount of 0.006 to 45 wt%, preferably 0.007 to 40 wt%, more preferably 0.01 to 35 wt%, relative to the weight of the first micro/nanoparticles in the mixture. For example, the amount of the polymer added is 0.006 wt%, 0.007 wt%, 0.008 wt%, 0.009 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 39 wt%, 38 wt%, 40 wt%, 25 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 1 wt%, 25 wt%, 9 wt%, 1 wt%, 25 wt%, 1 wt%, 25 wt%, 1 wt%, 25 wt%, 3 wt%, 25 wt%, 0., 41 wt%, 42 wt%, 43 wt%, 44 wt% or 45 wt%.

Further, the second nanoparticles are added in an amount of 0.001 to 60 wt%, preferably 0.01 to 50 wt%, more preferably 0.02 to 45 wt% with respect to the weight of the first micro/nanoparticles in the mixture. For example, the concentration of the second nanoparticles is 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 43 wt%, 42 wt%, 44 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 9 wt%, 10 wt%, 11 wt%, 13 wt%, 1 wt%, 3 wt%, 1 wt%, 3 wt%, 1 wt%, 25 wt%, 3 wt%, 25, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, or 60 wt%.

Furthermore, the preparation method of the photonic crystal adopts an interface assembly method; preferably, the preparation method is selected from one or more of a vertical sedimentation method, a blade coating method, a spin coating method, a roller coating method, a spray coating method, a dripping coating method and a film fishing method.

Further, the first micro/nanoparticle and the second nanoparticle are each independently selected from one or more of an organic micro/nanoparticle, an inorganic micro/nanoparticle, and an organic/inorganic composite micro/nanoparticle.

Still further, the organic micro/nanoparticles are prepared from organic matter.

Preferably, the organic micro/nanoparticles include one or more of carbon micro/nanoparticles, Polystyrene (PS), polymethyl methacrylate (PMMA), polydopamine, and PS @ PMMA.

Still further, the inorganic micro/nanoparticles are prepared from inorganic materials.

Preferably, the inorganic micro/nanoparticles include, but are not limited to, Silica (SiO)₂) Ferroferric oxide (Fe)₃O₄) Zinc sulfide (ZnS), zinc oxide (ZnO), cuprous oxide (Cu)₂O), cadmium sulfide (CdS), ZnS @ SiO₂、TiO₂@SiO₂And SiO₂@TiO₂One or more of the equal micron/nano particles.

Further, the organic/inorganic composite micro/nanoparticles include, but are not limited to, Fe₃O₄@PS、PS@TiO₂、PS@SiO₂、PS@SnO₂And composite micro/nanoparticles such as ZnS @ PS.

Further, the first micro/nanoparticles have a particle size of 0.01 to 50 μm, preferably 0.05 to 40 μm, and more preferably 0.1 to 25 μm. For example, the first micro/nanoparticles have a particle size of 0.1 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 40 μm or 50 μm.

Further, the second nanoparticles have a particle size of 1 to 1000nm, preferably 2 to 500nm, more preferably 5 to 300 nm. For example, the second nanoparticle has a particle size of 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm, 21nm, 22nm, 23nm, 24nm, 25nm, 26nm, 27nm, 28nm, 29nm, 30nm, 35nm, 40nm, 45nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000 nm.

Further, the polymer includes one or more of natural polymer and/or synthetic polymer.

Further, the natural polymer refers to a polymer which naturally exists in animals, plants and microorganisms and is not artificially synthesized. Preferably, the natural polymer includes, but is not limited to, one or more of starch, cellulose, chitin, lignin, protein, resin and rubber.

Further, the synthetic high molecular polymer refers to a high molecular polymer artificially synthesized. Preferably, the synthetic high molecular polymer includes one or more of, but is not limited to, starch derivatives, chitosan and derivatives thereof, cellulose derivatives, silk protein derivatives, lignin derivatives, resin derivatives, rubber derivatives, polylactic acid and derivatives thereof, polyacrylic acid and derivatives thereof, and polyolefin and derivatives thereof.

Furthermore, the large-area and functional preparation of the photonic crystal can be realized by utilizing the entropy-induced ordered assembly principle.

The invention also provides application of the photonic crystal prepared by the method in photonic crystal photoelectric devices, detection and analysis, catalysis, energy storage, food or intelligent packaging.

The invention has the unique points that:

compared with the traditional method for preparing the photonic crystal, the method utilizes the entropy-induced ordered assembly of the micron/nano particles and the polymer and/or the small-particle-size nano particles under the emptying effect to prepare the photonic crystal. Compared with the traditional interface self-assembly method, the method has simple and easy-to-implement process, and the prepared photonic crystal has uniform color and no crack, and can realize large-area preparation.

The invention has the beneficial effects that:

the invention develops a simple, universal and low-cost photonic crystal preparation method, which utilizes the mixing of polymer and/or small-particle-size nanoparticles and colloid nanoparticles, and prepares the photonic crystal by a co-assembly method, wherein the photonic crystal has uniform color, no crack and stable structure. Compared with the traditional method, the method has universality and popularization, and the application of photonic crystal photoelectric devices in the fields of detection and analysis, catalysis, energy storage, food, intelligent packaging and the like is promoted.

Drawings

FIG. 1 example 1 PS/HPC photonic crystals prepared by spin coating;

FIG. 2 SiO from example 2 by knife coating₂a/CA photonic crystal;

FIG. 3 PMMA/PEG photonic crystals prepared by knife coating method in example 3;

FIG. 4 example 4 PS/CMC photonic crystals prepared by vertical sedimentation;

FIG. 5 example 5 PS/carbon black photonic crystals prepared by the drop coating method;

FIG. 6 PS photonic crystals prepared by the knife coating method of comparative example 1;

FIG. 7 SiO as prepared by knife coating method in comparative example 2₂a/CA photonic crystal;

FIG. 8 SiO as prepared by knife coating in comparative example 3₂the/CA sample.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes or modifications can be made by those skilled in the art after reading the description of the present invention, and such equivalents also fall within the scope of the invention.

The starting materials are commercially available from the open literature unless otherwise specified.

Example 1

(1) Polystyrene (PS) colloidal spheres (the particle diameter of the PS colloidal spheres is 230nm), hydroxypropyl cellulose (HPC, CAS: 9004-64-2, product number: H0386, viscosity of 150-. In the mixed dispersion of the polystyrene colloidal spheres and the hydroxypropyl cellulose, the concentration of the colloidal spheres was 15 wt%. The amount of hydroxypropylcellulose added was 1 wt% based on the weight of the polystyrene colloidal spheres.

(2) PS/HPC photonic crystals were prepared using spin coating with a glass substrate (spin coated surface of substrate 1cm long by 1cm wide). And (3) taking 10 mu l of the dispersion liquid to spin-coat on a glass substrate, wherein the spin-coating speed is 2000rmp, and the spin-coating time is 120s, so that the PS/HPC photonic crystal is prepared. Scanning electron microscopy tests are shown in figure 1.

Example 2

(1) Mixing silicon dioxide (SiO)₂) Colloid ball (SiO)₂Spherical colloidal sphere particle diameter of 250nm), cellulose acetate (CAS: 9004-35-7, product number: a66697, acetyl 39.8 wt%, hydroxyl 3.5 wt%) (CA, substitution degree of 2.5) and N, N-Dimethylformamide (DMF), and subjecting to ultrasonic treatment for 30min to uniformly disperse the silica colloidal spheres and cellulose acetate to obtain a mixed dispersion of the silica colloidal spheres and the cellulose acetate. In the mixed dispersion of the silica colloidal spheres and cellulose acetate, the concentration of the silica colloidal spheres was 15 wt%. The amount of CA added was 0.8 wt% based on the weight of the silica colloidal spheres.

(2) Preparation of SiO by knife coating₂The substrate used is a glass substrate (the scratch coating surface of the substrate is 6cm in length and 3cm in width). Coating 20 μ l of the dispersion on a glass substrate at a blade pitch of 100 μm and a blade coating speed of 10mm/s, drying at room temperature for 30min, and making into a final productTo obtain SiO₂a/CA photonic crystal; the scanning electron microscopy test is shown in fig. 2.

Example 3

(1) Mixing polymethyl methacrylate (PMMA) colloidal spheres (the particle diameter of PMMA colloidal spheres is 245nm), polyvinyl alcohol (PEG, CAS: 9002-89-5, the product number is 178971000, 98.8% hydrolysis, the molecular weight is 31000-. In the mixed dispersion of the polymethyl methacrylate and the polyvinyl alcohol, the concentration of the polymethyl methacrylate colloidal spheres is 13 wt%. The amount of PEG added was 1.5% by weight based on the weight of polymethyl methacrylate (PMMA) colloidal spheres.

(2) And preparing the PMMA/PEG photonic crystal by using a blade coating method. The substrate used was a silicon wafer substrate (the knife coated surface of the substrate was 10cm long by 3cm wide). And then, taking 40 mu l of the dispersion liquid to scrape and coat on a silicon wafer substrate, wherein the distance between scrapers is 150 mu m, the scraping and coating speed is 15mm/s, and drying at room temperature for 20min to prepare the PMMA/PEG photonic crystal. Scanning electron microscopy tests are shown in figure 3.

Example 4

(1) Mixing Polystyrene (PS) colloidal spheres (the particle diameter of the PS colloidal spheres is 260nm), sodium carboxymethylcellulose (CMC, CAS: 9004-32-4, product number: A58821, polymerization degree of about 500, viscosity of 800-1200mPa & s) and water, and performing ultrasonic treatment for 30min to uniformly disperse the PS colloidal spheres and the CMC to obtain a mixed dispersion liquid of the Polystyrene (PS) colloidal spheres and the sodium carboxymethylcellulose. In the mixed dispersion of the polystyrene colloidal spheres and the sodium carboxymethylcellulose, the concentration of the polystyrene colloidal spheres is 0.2 wt%. The amount of CMC added was 1.2 wt% relative to the weight of Polystyrene (PS) colloidal spheres.

(2) And preparing the PS/CMC photonic crystal by using a vertical sedimentation method. The substrate is a glass substrate, the temperature of the constant temperature and humidity chamber is 60 ℃, and the relative humidity is 60%. And (3) in a constant temperature and humidity box, placing the glass substrate in PS/CMC mixed dispersion liquid, preparing photonic crystals by assembling PS colloidal spheres and CMC on the glass substrate, and preparing the PS/CMC photonic crystals after 48 hours. The scanning electron microscopy test is shown in fig. 4.

Example 5

(1) Polystyrene (PS) colloidal spheres (the particle diameter of the PS colloidal spheres is 230nm) and carbon black nano particles (Emperor)

2000, lot number 4837922, particle size 10nm) and water, and performing ultrasonic treatment for 30min to uniformly disperse the colloidal spheres and the carbon black to obtain a mixed dispersion of polystyrene colloidal spheres and carbon black nanoparticles. In the mixed dispersion of the polystyrene colloidal spheres and the carbon black nanoparticles, the concentration of the colloidal spheres is 5 wt%. The amount of carbon black nanoparticles added was 1 wt% relative to the weight of the polystyrene colloidal spheres.

(2) PS/HPC photonic crystals were prepared by drop coating using a glass substrate (1 cm long by 1cm wide of the drop coated surface of the substrate). And (3) placing the glass substrate on a 60 ℃ hot table, dripping 50 mu l of the dispersion liquid on the glass substrate, and drying for 40min to obtain the PS/carbon black photonic crystal. The scanning electron microscopy test is shown in fig. 5.

Comparative example 1

Preparing Polystyrene (PS) photonic crystals by a knife coating method. PS colloidal spheres (PS spheres having a diameter of 220nm) were dispersed in deionized water to prepare a colloidal sphere dispersion. The colloidal sphere dispersion is PS colloidal sphere water dispersion with the concentration of 10 wt%. The substrate used was a silicon wafer substrate (the blade coated surface of the substrate was 6cm in length by 3cm in width). And (3) dropping 20 mul of the dispersion liquid on a silicon wafer substrate, preparing the photonic crystal by a blade coating method, wherein the distance between blades is 150 mu m, the blade coating speed is 15mm/s, drying is carried out for 15min at room temperature, and the PS photonic crystal is prepared, wherein a scanning electron microscope proves that the assembling condition of the PS photonic crystal is poor, and a plurality of dislocations and cracks exist on the surface, as shown in figure 6.

Comparative example 2

(1) Mixing silicon dioxide (SiO)₂) Colloid ball (SiO)₂Spherical colloidal sphere particle diameter of 250nm), cellulose acetate (CAS: 9004-35-7, product number: a66697, acetyl 39.8 wt%, hydroxyl 3.5 wt%) (CA, substitution degree of 2.5) and N, N-Dimethylformamide (DMF), and subjecting to ultrasonic treatment for 30min to uniformly disperse the silica colloid spheres and cellulose acetate to obtain a mixed dispersion of the silica colloid spheres and the cellulose acetate. The second mentionedIn the mixed dispersion of silica colloidal spheres and cellulose acetate, the concentration of silica colloidal spheres was 15 wt%. The amount of CA added was 0.005% by weight based on the weight of the silica colloidal spheres.

(2) Preparation of SiO by knife coating₂The substrate used is a glass substrate (the scratch coating surface of the substrate is 6cm in length and 3cm in width). Coating 20 μ l of the dispersion on a glass substrate at a blade pitch of 100 μm and a blade coating speed of 10mm/s, and drying at room temperature for 30min to obtain SiO₂Cracks and defects exist on the surface of the/CA photonic crystal; the scanning electron microscopy test is shown in fig. 7.

Comparative example 3

(1) Mixing silicon dioxide (SiO)₂) Colloid ball (SiO)₂Spherical colloidal sphere particle diameter of 250nm), cellulose acetate (CAS: 9004-35-7, product number: a66697, acetyl 39.8 wt%, hydroxyl 3.5 wt%) (CA, substitution degree of 2.5) and N, N-Dimethylformamide (DMF), and subjecting to ultrasonic treatment for 30min to uniformly disperse the silica colloid spheres and cellulose acetate to obtain a mixed dispersion of the silica colloid spheres and the cellulose acetate. In the mixed dispersion of the silica colloidal spheres and cellulose acetate, the concentration of the silica colloidal spheres was 15 wt%. The amount of CA added was 50% by weight based on the weight of the silica colloidal spheres.

(2) Preparation of SiO by knife coating₂The substrate used is a glass substrate (the scratch coating surface of the substrate is 6cm in length and 3cm in width). Coating 20 μ l of the dispersion on a glass substrate at a blade pitch of 100 μm and a blade coating speed of 10mm/s, and drying at room temperature for 30min to obtain SiO₂SiO in the/CA sample₂No assembly of the nanoparticles occurred; the scanning electron microscopy test is shown in fig. 8.

The invention has not been described in detail and is within the knowledge of a person skilled in the art. The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and the preferred embodiments are not exhaustive and do not limit the invention to the precise embodiments described. Various modifications and improvements of the technical solution of the present invention may be made by those skilled in the art without departing from the spirit of the present invention, and the technical solution of the present invention is to be covered by the protection scope defined by the claims.

Claims

1. A preparation method of photonic crystals is characterized in that raw materials for preparing the photonic crystals comprise: (1) a first micro/nanoparticle; and (2) a polymer and/or at least one second nanoparticle;

mixing the raw materials to form a mixture, and then preparing the photonic crystal by a co-assembly method;

wherein, the micron/nano particles refer to micron-sized particles or nano-sized particles, and the particle diameter of the first micron/nano particles is larger than that of the second nano particles.

2. The method of claim 1, wherein the first micro/nanoparticles concentration in the mixture is 0.001 to 75 wt%, preferably 0.005 to 65 wt%, more preferably 0.01 to 60 wt%;

the polymer is added in an amount of 0.006 to 45 wt%, preferably 0.007 to 40 wt%, more preferably 0.01 to 35 wt%, relative to the weight of the first micro/nanoparticles;

the second nanoparticles are added in an amount of 0.001 to 60 wt%, preferably 0.01 to 50 wt%, more preferably 0.02 to 45 wt% with respect to the weight of the first micro/nanoparticles.

3. The method according to claim 1 or 2, wherein the photonic crystal is prepared by an interface assembly method;

preferably, the preparation method is selected from one or more of a vertical sedimentation method, a blade coating method, a spin coating method, a roller coating method, a spray coating method, a dripping coating method and a film fishing method.

4. The method of claim 1 or 2, wherein the first micro/nanoparticle and the second nanoparticle are each independently selected from one or more of an organic micro/nanoparticle, an inorganic micro/nanoparticle, an organic/inorganic composite micro/nanoparticle;

preferably; the organic micron/nano particles are selected from one or more of carbon micron/nano particles, Polystyrene (PS), polymethyl methacrylate (PMMA), polydopamine and PS @ PMMA micron/nano particles;

preferably, the inorganic micro/nanoparticles are selected from Silica (SiO)₂) Ferroferric oxide (Fe)₃O₄) Zinc sulfide (ZnS), zinc oxide (ZnO), cuprous oxide (Cu)₂O), cadmium sulfide (CdS), ZnS @ SiO₂、TiO₂@SiO₂And SiO₂@TiO₂One or more of micron/nano particles;

preferably, the organic/inorganic hybrid micro/nanoparticles are selected from Fe₃O₄@PS、PS@TiO₂、PS@SiO₂、PS@SnO₂And one or more of ZnS @ PS composite micro/nanoparticles.

5. The method according to claim 1, wherein the first micro/nanoparticles have a particle size of 0.01-50 μ ι η, preferably 0.05-40 μ ι η, more preferably 0.1-25 μ ι η;

the second nanoparticles used have a particle size of 1 to 1000nm, preferably 2 to 500nm, more preferably 5 to 300 nm.

6. The method according to claim 1, wherein the polymer comprises a natural polymer or/and a synthetic polymer;

preferably, the natural polymer is a polymer compound naturally existing in animals, plants, microorganisms or minerals and formed by biochemical action or photosynthesis;

more preferably, the natural polymer is selected from one or more of starch, cellulose, chitin, lignin, protein, resin and rubber;

preferably, the synthetic high molecular polymer is a high molecular polymer obtained by polymerization of a small molecular compound or modified by chemical groups of natural high molecules;

more preferably, the synthetic high molecular polymer is selected from one or more of starch derivatives, chitosan and derivatives thereof, cellulose derivatives, silk protein derivatives, lignin derivatives, resin derivatives, rubber derivatives, polylactic acid and derivatives thereof, polyacrylic acid and derivatives thereof, and polyolefin and derivatives thereof.

7. The photonic crystal prepared by the method of any one of claims 1 to 6 is applied in the fields of photonic crystal photoelectric devices, detection and analysis, catalysis, energy storage, food or intelligent packaging.