Preparation method of short-range ordered iridescent nano-film with adjustable transparency

Abstract

The invention relates to a preparation method of a short-range ordered iridescent nano-film with adjustable transparency. The preparation method specifically comprises the following steps: 1, assembling two-phase interface metal nanoparticles and transferring the two-phase interface metal nanoparticles to a required substrate; 2, dispersing the polystyrene spheres by using n-butyl alcohol, and assembling a short-distance ordered structure on the water surface and realizing transfer; 3, heating the sample to a temperature higher than the glass transition temperature of polystyrene, and keeping the temperature for a period of time, so that the polystyrene collapses to cover part of the metal nanoparticles; 4, cleaning the unprotected metal nanoparticles; and 5, removing the polystyrene spheres so as to leave a short-distance ordered metal particle structure on the substrate. According to the method, the iridescent film with controllable color appearance, adjustable transparency and nanoscale thickness can be obtained, and the method has important application prospects in the fields of counterfeiting prevention, appearance decoration and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nano-manufacturing, and in particular relates to a method for preparing a short-range ordered rainbow-colored nano film with adjustable transparency. Background Art

[0002] In 1665, Newton first used a prism to separate white light into seven colors, allowing people to see artificial "rainbows" for the first time, and opening up people's pursuit of the nature of color. After several centuries, scientists have had a deeper understanding of the causes of color in animals and plants in nature. On the one hand, color can be produced by the energy band transition of electrons in dye molecules (such as anthocyanins and chlorophyll). On the other hand, there are micro-nano structures in certain bird feathers and butterfly wings, and the interference, diffraction, and scattering effects of light in them can also produce colors. These colors are collectively referred to as structural colors. At present, most structural colors in nature are believed to be produced by the following five basic optical processes and their combinations: thin film interference, multilayer interference, diffraction grating effect, photonic crystals, and light scattering. With the development of micro-nano processing technology, a variety of artificial structural color schemes have been gradually proposed, such as dielectric photonic crystal structures, surface plasmon colloidal nanostructures, metal-dielectric-metal sandwich structures, and so on. Compared with traditional dyes, the structural colors of artificial micro-nano structures have multiple advantages such as ultra-high resolution, ultra-thin thickness (submicron level), ultra-light weight, long-term stability, and low toxicity, and have received widespread attention and research.

[0003] As the research deepens, many scholars and designers think about the mechanism of forming a colorful appearance by regulating the micro-scale arrangement. In 2023, some scholars proposed an explanatory, intuitive and accurate modal-based tool, the BRDF model, which reveals the main physical mechanisms and characteristics, theoretically studies the origin of the colorful appearance, and can be used to describe the mathematical model of light reflection characteristics. This multidimensional radiation function describes how the metasurface scatters all possible plane waves, taking into account the angle of the incident light, the angle of the outgoing light, and the wavelength of the light. It is found that colloidal crystals are crystalline structures composed of nanostructures of predetermined order and period. Due to the micro-nanoscale, ordered particle arrangement and material properties, unique optical phenomena are produced, and conditions are created for photonic crystals, structural colors, etc. Colloidal self-assembly is a simple and effective method to construct colloidal crystal structures. However, the traditional self-assembly method is not only time-consuming, but also produces a small area of ​​​​colloid crystals. It was found that by constructing a stable and continuous liquid-air interfacial tension gradient, the resulting Marangoni effect can drive nanoparticles to obtain nearly 50kT of kinetic energy in a short period of time, immediately overcoming the free energy barrier between particles (formed by electrostatic repulsion, usually several kT), and forming highly ordered colloidal crystals. Thanks to the long-range surface tension gradient, the fabrication area of ​​colloidal crystal films has been demonstrated to exceed an astonishing 1000 square centimeters without affecting its quality, showing great potential for large-scale manufacturing. Particles of various sizes, materials and functions can form tightly packed self-assembled monolayers and be transferred to various substrates without damage, showing great versatility.

[0004] At present, people have an increasing demand for personalized colorful appearance. Using nanostructures as basic units, constructing nanostructured metasurfaces can achieve appearances that traditional materials cannot achieve, such as the separate control of halo and color. In 2022, Philippe Lalanne and others from the University of Lyon in France further expanded the concept of structural color of nanomaterials in the paper "Nature Materials", proposed the concept of "visual appearance" of nanomaterials, emphasized that specular reflection and diffuse reflection components, light sources and detection positions, etc. will affect people's real perception, and theoretically predicted the existence of "diffuse reflection rainbow colors" and "diffuse reflection halos" in disordered metasurface structures. Unique phenomena that do not exist in nature. They also predicted that colloidal nanostructures are expected to achieve large-scale colorful structural processing, pointing out a new direction for the study of colorful effects of micro-nano structures. Against this background, in 2023, the Southeast University team used the multi-scale pattern transfer process of colloidal nanostructures to achieve colorful patterns, and studied the changes in the pattern appearance of long-range ordered structures under different light source excitations and observation angles.

[0005] Compared with long-range ordered nanostructures, short-range ordered nanostructures can achieve rainbow color distribution with a wide viewing angle. However, at present, the processing of short-range ordered nanostructures usually relies on the self-assembly stacking of nanostructures, and the thickness is usually hundreds of microns. It is difficult to have rainbow color distribution due to poor controllability and is not transparent. How to construct short-range ordered structures over a large area to take into account nanoscale thickness, adjustable transparency and colorful appearance is an unresolved problem. Summary of the invention

[0006] Technical problem: The purpose of the present invention is to provide a method for preparing a short-range ordered rainbow-colored nanofilm with adjustable transparency, to solve the problem of how to design to achieve a rainbow-colored structure at the nanoscale, and to solve the problem of simultaneously achieving controllable nanostructure, adjustable transparency and controllable color appearance.

[0007] Technical solution: The preparation method of a short-range ordered rainbow color nano film with adjustable transparency of the present invention specifically comprises the following steps:

[0008] Step 1: Assembly and transfer of metal nanoparticles at the two-phase interface: The metal nanoparticles are self-assembled into a dense monolayer at the gas-liquid or liquid-liquid interface and transferred to the desired substrate;

[0009] Step 2: Short-range ordered assembly and transfer of polystyrene balls at the water-air interface: The first polystyrene balls are dispersed in n-butanol, and the first polystyrene ball solution dispersed in n-butanol is dripped dropwise onto the water-air interface. The first polystyrene balls on the interface are distributed in a short-range order by using the Marangoni effect and the interaction force between particles. The close-packed metal nanoparticles are placed parallel to the liquid surface where the polystyrene microspheres are assembled, and pressed downward, so that the first polystyrene balls form a short-range ordered structure and then transferred to the substrate with the metal nanoparticles, thereby obtaining a first polystyrene ball-metal nanoparticle composite structure.

[0010] Step 3: Thermal collapse of the second polystyrene balls: The first polystyrene ball-metal nanoparticle composite structure is heated to 115-130 degrees Celsius and maintained at this temperature for more than 10 seconds, so that the first polystyrene balls are connected and collapsed to obtain the second polystyrene balls, which in turn cover part of the metal nanoparticles;

[0011] Step 4: Cleaning the metal nanoparticles not protected by the second polystyrene balls: using ultrapure water or combining ultrasonic method to remove the metal nanoparticles on the substrate that are not covered by the second polystyrene balls;

[0012] Step 5: Removal of the second polystyrene spheres: The second polystyrene spheres are removed by washing with an organic solvent, dry etching or heating, thereby leaving short-range ordered transparent metal nanoparticles on the substrate, thereby showing a rainbow appearance.

[0013] The metal nanoparticles, wherein the metal includes gold, silver, platinum, copper, aluminum, palladium or alloy materials composed of two or more thereof, have a size of 5 to 100 nanometers.

[0014] The assembly method of the metal nanoparticles is:

[0015] Method 1: Put the prepared metal nanoparticles into a glass bottle, then use ethanol / n-hexane as a solvent to prepare a perfluorodecanethiol dispersion, and pour the dispersion into the metal nanoparticles, shake, and obtain a metal nanoparticle monolayer film after stabilization;

[0016] Method 2: First, toluene containing oleylamine is added to a citric acid-stabilized aqueous solution of metal nanoparticles, and the mixture is shaken vigorously to form a two-phase mixture. After standing, the aqueous phase is discarded to obtain a toluene phase oil phase containing metal nanoparticles; the toluene phase is mixed with ultrapure water, stirred at high speed to form a mixture, and after standing, the toluene phase containing metal nanoparticles is collected by a one-time washing; next, the toluene phase is washed with water to obtain oleylamine-coated metal nanoparticles; toluene / diethylene glycol is added to a clean container, and the toluene phase containing oleylamine-coated metal nanoparticles is spread on the surface of the toluene / diethylene glycol, the container is covered with a glass slide, and the toluene is slowly evaporated to allow the oleylamine-coated metal nanoparticles to self-assemble; after the toluene is evaporated, a self-assembled monolayer film of oleylamine-coated metal nanoparticles is formed on the surface of the toluene / diethylene glycol.

[0017] The material of the substrate includes aluminum oxide, quartz, glass sheet or glass sheet coated with indium tin oxide.

[0018] The short-range ordered structure of the first polystyrene spheres at the subwavelength scale is achieved by adjusting the size of the first polystyrene spheres and the mass percentage of the first polystyrene spheres with n-butanol to achieve a short-range ordered structure at the water-air two-phase interface. The size of the first polystyrene spheres is 300 nanometers to 5 micrometers.

[0019] The method for removing the second polystyrene balls includes washing with an organic solvent, heating, oxygen plasma etching, inductive coupling, plasma etching or reactive ion etching.

[0020] The organic solvent is acetone, toluene or chloroform.

[0021] When the second polystyrene ball is removed by heating, the heating temperature is 600 to 1500 degrees and the time is 10 minutes to 5 hours.

[0022] The peak q wave vector q of the technical indicator structure factor S(q) of the short-range ordered distribution || Between 0.2 / micron and 25 / micron, here where q = k i-k s ,k i is the incident light wave vector, k s is the scattered light wave vector, N is the total number of the first polystyrene balls, r i , r j are the position vectors of the center of the i-th and j-th polystyrene spheres, q || is the q-wave vector parallel to the water-air interface.

[0023] The mass percentage of the first polystyrene balls and n-butanol is 0.1 wt % to 20 wt %.

[0024] Beneficial effects: Compared with the existing technology, the present invention has the following advantages:

[0025] 1. The processing method of the short-range ordered transparent metal nanoparticle rainbow structure proposed in the present invention utilizes the collapse of polystyrene to cover and protect part of the metal nanoparticles. The short-range disordered structure of the gold nanoparticles can be controlled by controlling the concentration of polystyrene balls, thereby achieving adjustable transparency and controllable color appearance.

[0026] 2. Compared with the traditional bottom-up and top-down self-assembly techniques, the processing method of the short-range ordered transparent metal nanoparticle rainbow structure proposed in the present invention does not require complex instruments and can achieve spacing control that cannot be achieved by ordinary self-assembly methods, thereby realizing a short-range ordered structure and producing a unique rainbow appearance.

[0027] 3. The nanomanufacturing technology proposed in the present invention has low manufacturing process cost, simple and convenient operation, economical use of instruments and materials, and is easy to mass produce and put into use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process of the processing method of transparent short-range ordered rainbow color structure.

[0029] The figure includes: substrate 1, metal nanoparticles 2, first polystyrene balls 3, liquid surface of polystyrene microspheres 4, and second polystyrene balls 5. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0031] The present invention proposes a method for preparing a short-range ordered rainbow color nano film with adjustable transparency. The specific principle of realizing a nano-scale film with controllable colorful appearance is as follows:

[0032] In order to achieve rainbow colors with short-range ordered structures, it is necessary to construct nanostructure distribution with wavelength-scale spacing. In this paper, polystyrene nanospheres with wavelength-scale sizes are selected as carriers to achieve wavelength-scale spacing nanostructures. The short-range order is achieved through the Marangoni effect, electrostatic repulsion and initial non-uniform drop acceleration rate of polystyrene nanospheres on the water surface. The source of short-range order comes from the size limitation of polystyrene nanospheres themselves and the control of the maximum spacing between particles. In addition, the different initial velocities of nanospheres dispersed in n-butanol at low temperatures on the water surface cause their random movement on the water surface, resulting in long-range order. The self-assembly of polystyrene nanospheres of wavelength scale on the liquid surface ensures the short-range order.

[0033] Since the transparency of the nano film is related to the concentration of the metal nanoparticles, and also to the spacing and shape between the nanoparticles, etc. Therefore, the density of the metal nanoparticles formed on the substrate can be controlled by controlling the concentration of the polystyrene template. The greater the density of the metal nanoparticles, the smaller the lightness of the transparent film, and the smaller the density of the metal nanoparticles, the greater the lightness of the transparent film, thereby realizing local control of the transparency of the film. Since the spacing of the metal nanoparticles also meets the spacing of the wavelength order, it has a strong diffraction effect on the light wave, thus having a rainbow appearance. The rainbow film with controllable color appearance, adjustable transparency and nanometer-level thickness can be prepared by the processing method of the short-range ordered transparent gold nanoparticle rainbow structure proposed by the present invention.

[0034] The preparation method of a short-range ordered rainbow-colored nanofilm with adjustable transparency proposed by the present invention specifically includes the following steps: the first step: assembly and transfer of metal nanoparticles at the two-phase interface, the metal nanoparticles 2 are densely self-assembled in a single layer at the gas-liquid or liquid-liquid interface, and transferred to the desired substrate 1. The second step: short-range ordered assembly and transfer of polystyrene balls at the water-air interface, a certain concentration of polystyrene balls are dispersed in n-butanol, and dripped onto the water-air interface drop by drop, and the polystyrene balls on the interface are distributed in a short-range order by using the Marangoni effect and the interaction force between particles, and the peak q wave vector q of the technical indicator structure factor S(q) of the short-range ordered distribution is 1. ∥It is between 0.2 / micron and 25 / micron. The sample with densely packed metal nanoparticles 2 is placed parallel to the liquid surface 4 assembled with polystyrene microspheres, and pressed downward, so that the first polystyrene balls (3) form a short-range ordered structure and then transferred to the substrate 1 with metal nanoparticles 2. The third step: thermal collapse of the first polystyrene balls 3. The above sample is heated to 115-130 degrees Celsius. At this temperature, it is maintained for a certain period of time, and the first polystyrene balls 3 will collapse and then cover part of the metal nanoparticles 2. The fourth step: cleaning the metal nanoparticles not protected by the polystyrene balls. Use ultrapure water to clean or combine ultrasonic methods to remove the metal nanoparticles not covered by polystyrene on the substrate. The fifth step: removal of the second polystyrene balls 5. The polystyrene template is removed by washing with organic solvents, dry etching or heating, thereby leaving a short-range ordered transparent metal nanoparticle structure on the substrate, thereby showing a rainbow appearance.

[0035] The materials and nanomaterial processing technology selected for the processing method of the short-range ordered transparent gold nanoparticle rainbow structure proposed by the present invention include: the metal nanoparticles assembled at the two-phase interface are gold, silver, platinum, copper, aluminum, palladium or alloy materials composed of two or more of them, the size of the 3 nanoparticles is 5 to 500 nanometers, the gas-liquid interface may include air-water, air-ethylene glycol, air-ethylene glycol, the liquid-liquid interface includes n-hexane-water, toluene-water, and the substrate material may include aluminum oxide, quartz, glass sheet, glass sheet coated with indium tin oxide, etc.

[0036] The method for processing the short-range ordered transparent gold nanoparticle rainbow color structure proposed by the present invention to remove part of the polystyrene ball template includes: organic solvent washing, heating, inductively coupled plasma etching and reactive ion etching. The organic solvent can be acetone, toluene, and chloroform. When the polystyrene ball is removed by heating, the heating temperature is 600 to 1500 degrees and the time is 10 minutes to 5 hours.

[0037] The processing method of the short-range ordered transparent gold nanoparticle rainbow structure proposed by the present invention has various realization methods. Therefore, the specific implementation methods and operation processes are different according to different preparation processes and material properties. All the following embodiments are implemented on the premise of the technical solution of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0038] Embodiment 1:

[0039] Self-assembled polystyrene nanoparticles are prepared at the air-water interface, and the short-range ordered rainbow color structure processing method proposed by the present invention is applied. The specific preparation process steps are as follows: Figure 1 As shown:

[0040] Step 1: Densely assemble the gold nanoparticles into a monolayer at the air-liquid interface. Place 5 ml of the newly prepared gold nanocolloid into a glass bottle. Then, pour perfluorodecanethiol solution (10 mmol / L, 10 ml, ethanol: n-hexane = 2:1) into the gold nanosolution and shake for 3 seconds. After stabilization, a monolayer of gold nanoparticles is obtained, and the densely packed monolayer nanoparticles are transferred to the desired substrate 1.

[0041] Step 2: Through the self-assembly process, the first polystyrene balls 3 with a mass percentage of 2.5wt% (which can achieve the control of transparency and rainbow color distribution) are distributed in a short-range orderly manner on the liquid surface 4 of the water-air polystyrene microspheres, wherein the size of the first polystyrene balls 3 is 600 nanometers. At this time, the peak q wave vector q of the structure factor ∥ About 12 / micron.

[0042] Step 3: Place the substrate 1 adsorbed with gold nanoparticles parallel to the liquid surface 4 of polystyrene microspheres and press downward so that the first polystyrene spheres 3 form a short-range ordered structure and then transfer it to the substrate 1 with metal nanoparticles 2 to obtain a first polystyrene sphere-metal nanoparticle composite structure.

[0043] Step 4: heating the first polystyrene ball-metal nanoparticle composite structure to 120 degrees Celsius and maintaining it at this temperature for 1 minute, so that the first polystyrene balls are connected to each other and collapsed, thereby obtaining second polystyrene balls 5, which in turn cover part of the metal nanoparticles 2;

[0044] Step 5: Use ultrapure water to wash or combine with ultrasonic method to remove the gold nanoparticles not covered by polystyrene, and the remaining gold nanoparticles covered by polystyrene balls 5.

[0045] Step 6: Rinse with organic solvent to remove the polystyrene template and obtain gold nanoparticles distributed in a controllable short-range order.

[0046] The assembly method of the metal nanoparticles is:

[0047] Method 1: 5 to 10 ml of the prepared metal nanoparticles are placed in a glass bottle, and then, ethanol / n-hexane with a volume ratio of 2:1 is used as a solvent to prepare a perfluorodecanethiol dispersion with a volume of 10 to 20 ml and a concentration of 10 mmol / L, and the dispersion is poured into the metal nanoparticles, shaken for 3 to 5 seconds, and a metal nanoparticle monolayer film is obtained after stabilization;

[0048] Method 2: First, add 1 to 5 ml of toluene containing 1 mmol / L oleylamine to 5 to 10 ml of citric acid-stabilized aqueous solution of metal nanoparticles, shake vigorously to form a two-phase mixture, and after standing, discard the aqueous phase to obtain a toluene phase oil phase containing metal nanoparticles; mix the toluene phase with ultrapure water in a volume ratio of 5:1, stir at high speed for 3 to 5 minutes to form a mixture, and stand for 3 to 5 hours; then, collect the toluene phase containing metal nanoparticles by a one-time washing; next, wash the toluene phase with water 3 to 5 times to obtain oleylamine-coated metal nanoparticles; add 15 to 20 ml of toluene / diethylene glycol to a clean container, spread the toluene phase containing oleylamine-coated metal nanoparticles on the surface of toluene / diethylene glycol, cover the container with a glass slide, slowly evaporate the toluene to allow the oleylamine-coated metal nanoparticles to self-assemble; after 180 to 250 minutes, the toluene evaporation is completed, and a self-assembled monolayer film of oleylamine-coated metal nanoparticles is formed on the surface of toluene / diethylene glycol.

Claims

1. A method for preparing a short-range ordered rainbow color nanofilm with adjustable transparency, characterized in that The specific steps include: Step 1: Assembly and transfer of metal nanoparticles at the two-phase interface: The metal nanoparticles (2) are self-assembled into a dense monolayer at the gas-liquid or liquid-liquid interface and transferred to the desired substrate (1); Step 2: short-range ordered assembly and transfer of polystyrene balls at the water-air interface: first polystyrene balls (3) are dispersed in n-butanol, and the first polystyrene ball (3) solution dispersed in n-butanol is dripped dropwise onto the water-air interface, and the first polystyrene balls (3) on the interface are distributed in a short-range ordered manner by using the Marangoni effect and the interaction force between particles, and the liquid surface (4) with close-packed metal nanoparticles (2) is placed parallel to the liquid surface (4) assembled with polystyrene microspheres, and pressed downward, so that the first polystyrene balls (3) form a short-range ordered structure and then transferred to the substrate (1) with the metal nanoparticles (2), thereby obtaining a first polystyrene ball-metal nanoparticle composite structure; Step 3: Thermal collapse of the second polystyrene balls (5): The first polystyrene ball-metal nanoparticle composite structure is heated to 115-130 degrees Celsius and maintained at this temperature for more than 10 seconds, so that the first polystyrene balls are connected to each other and collapsed, thereby obtaining the second polystyrene balls (5), which in turn cover part of the metal nanoparticles (2); Step 4: Cleaning the metal nanoparticles not protected by the second polystyrene balls: using ultrapure water or ultrasonic method to remove the metal nanoparticles (2) on the substrate (1) that are not covered by the second polystyrene balls (5); Step 5: Removal of the second polystyrene balls (5): The second polystyrene balls (5) are removed by washing with an organic solvent, dry etching or heating, thereby leaving short-range ordered transparent metal nanoparticles (2) on the substrate (1), thereby showing a rainbow appearance.

2. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1, characterized in that The metal nanoparticles (2) include gold, silver, platinum, copper, aluminum, palladium or alloy materials composed of two or more thereof, and the size of the nanoparticles is 5 to 100 nanometers.

3. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1 or 2, characterized in that The assembly method of the metal nanoparticles (2) is: Method 1: Put the prepared metal nanoparticles (2) into a glass bottle, then use ethanol / n-hexane as a solvent to prepare a perfluorodecanethiol dispersion, and pour the dispersion into the metal nanoparticles (2), shake, and obtain a metal nanoparticle monolayer film after stabilization; Method 2: First, toluene containing oleylamine is added to a citric acid-stabilized aqueous solution of metal nanoparticles, and the mixture is shaken vigorously to form a two-phase mixture. After standing, the aqueous phase is discarded to obtain a toluene phase oil phase containing metal nanoparticles; the toluene phase is mixed with ultrapure water, stirred at high speed to form a mixture, and after standing, the toluene phase containing metal nanoparticles is collected by a one-time washing; next, the toluene phase is washed with water to obtain oleylamine-coated metal nanoparticles (2); toluene / diethylene glycol is added to a clean container, and the toluene phase containing oleylamine-coated metal nanoparticles (2) is spread on the surface of the toluene / diethylene glycol, and the container is covered with a glass slide, and the toluene is slowly evaporated to allow the oleylamine-coated metal nanoparticles (2) to self-assemble; after the toluene is evaporated, a self-assembled monolayer film of oleylamine-coated metal nanoparticles (2) is formed on the surface of the toluene / diethylene glycol.

4. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1, characterized in that The material of the substrate (1) includes aluminum oxide, quartz, a glass sheet or a glass sheet coated with indium tin oxide.

5. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1, characterized in that The first polystyrene sphere (3) realizes a short-range ordered structure at a subwavelength scale, that is, the size of the first polystyrene sphere (3) and its mass percentage with n-butanol are adjusted to realize a short-range ordered structure at the water-air two-phase interface. The size of the first polystyrene sphere (3) is 300 nanometers to 5 micrometers.

6. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1, characterized in that The method for removing the second polystyrene balls (5) includes washing with an organic solvent, heating, oxygen plasma etching, inductive coupling, plasma etching or reactive ion etching.

7. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 6, characterized in that The organic solvent is acetone, toluene or chloroform.

8. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 6, characterized in that When the second polystyrene ball (5) is removed by heating, the heating temperature is 600 to 1500 degrees and the time is 10 minutes to 5 hours.

9. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1, characterized in that The peak q wave vector q of the technical indicator structure factor S(q) of the short-range ordered distribution ∥ Between 0.2 / micron and 25 / micron, here where q = k i -k s ,k i is the incident light wave vector, k s is the scattered light wave vector, N is the total number of the first polystyrene balls (3), r i , r j are the position vectors of the centers of the i-th and j-th first polystyrene balls (3), q ∥ is the q-wave vector parallel to the water-air interface.

10. The method for preparing a short-range ordered rainbow color nano film with adjustable transparency according to claim 1, characterized in that The mass percentage of the first polystyrene balls and n-butanol is 0.1 wt % to 20 wt %.

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