Structural color film with adjustable brightness and preparation method thereof

Abstract

The invention relates to the technical field of films, and particularly discloses a brightness-adjustable structural color film and a preparation method thereof. The structural color film is of a three-layer structure; the three-layer structure sequentially comprises a structural color layer, a dimming layer and a reflecting layer from top to bottom; the reflecting layer comprises at least one of an aluminum sheet, a silver mirror, polytetrafluoroethylene and a white paint sheet; the thickness of the dimming layer ranges from 0.2 mm to 1 mm. The structural color film is prepared in a physical processing mode, environmental pollution is effectively reduced, the production cost is reduced, the resource utilization rate is increased, and the requirement for sustainable development is met. The low absorption characteristic of the thin film significantly reduces heat accumulation, and the color can be flexibly regulated and controlled by optimizing the parameters of the structural color layer. In addition, the transmittance of the middle dimming layer can be adjusted by adjusting and controlling the voltage of the brightness of the colored film, accurate adjustment according to needs is achieved, the color stability is high, the brightness can be adjusted, and high practicability and reliability are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of thin films, and in particular to a brightness-adjustable structural color film and a preparation method thereof. Background Art

[0002] In recent years, energy conservation and emission reduction have become an important strategy for addressing climate change, promoting green and low-carbon transformation, optimizing energy structure, and improving energy efficiency to achieve carbon peak and carbon neutrality goals. To this end, promoting green technology, implementing energy-saving transformation and optimizing energy structure have become key measures. At the same time, green and low-carbon development has been established as a key direction, aiming to promote energy structure adjustment, improve energy efficiency and reduce pollution emissions.

[0003] Color films are widely used in decoration, beautification and UV resistance, covering multiple industries such as construction, automobiles, electronic products and daily home, providing users with visual enjoyment and functional convenience. However, most color films are still prepared chemically, which is often accompanied by the generation of toxic waste and chemical by-products, resulting in high energy consumption and environmental pollution, increasing production costs and affecting resource utilization efficiency. In addition, since the color of color films usually depends on chemical pigment materials, the accuracy and saturation of their colors are easily affected by environmental factors, resulting in poor color stability. When generating chemical pigments, most materials will have absorption phenomena and have heat absorption characteristics, which may cause heat accumulation and increase the thermal load of the equipment. At the same time, adjusting the color and brightness of the film usually requires the reuse of chemical processes, which lacks flexibility and cannot quickly adapt to different application requirements. Due to the reliance on chemical pigments, the color accuracy and stability of traditional color films are easily affected by environmental factors (such as temperature and humidity), resulting in color fading or shifting.

[0004] Therefore, it is necessary to provide a brightness-adjustable structural color film and a preparation method thereof, which can flexibly control the brightness and achieve precise adjustment on demand with high practicality and reliability. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a brightness-adjustable structural color film and a preparation method thereof, which can flexibly control the brightness and achieve precise adjustment on demand, and has high practicality and reliability.

[0006] A first aspect of the present invention provides a brightness-adjustable structural color film.

[0007] Specifically, the structural color film is a three-layer structure;

[0008] The three-layer structure includes, from top to bottom, a structural color layer, a dimming layer, and a reflective layer;

[0009] The reflective layer includes at least one of aluminum sheet, silver mirror, polytetrafluoroethylene, and white paint sheet;

[0010] The thickness of the dimming layer is 0.2-1 mm.

[0011] Preferably, the dimming layer has a thickness of 0.2-0.5 mm.

[0012] Preferably, the thickness of the structural color layer is 1000-3000 nm.

[0013] Further preferably, the thickness of the structural color layer is 1000-2800 nm.

[0014] More preferably, the thickness of the structural color layer is 1100-2700 nm.

[0015] Preferably, the material of the structural color layer includes at least one of SiO2, ZrO2, Al2O3, TiO2, and Ta2O5.

[0016] Preferably, the thickness of the reflective layer is 0.1-2 mm.

[0017] Preferably, the material of the dimming layer includes any one of a nematic liquid crystal material, a liquid dispersion of titanium dioxide particles, and a liquid dispersion of zinc oxide particles.

[0018] Preferably, the reflectivity of the reflective layer is 85-98%.

[0019] More preferably, the reflectivity of the reflective layer is 90-98%.

[0020] More preferably, the reflectivity of the reflective layer is 95-98%.

[0021] A second aspect of the present invention provides a method for preparing a structural color film.

[0022] Specifically, the following steps are included:

[0023] (1) The materials of the structural color layer are alternately stacked by physical deposition to form a structural color layer;

[0024] (2) dispersing the material of the dimming layer on the substrate, spin coating, photocuring, and annealing to obtain the dimming layer;

[0025] (3) The reflective layer, the dimming layer, and the structural color layer are stacked from bottom to top to obtain a structural color film.

[0026] Preferably, in step (1), the physical deposition method includes evaporation deposition and magnetron sputtering.

[0027] Preferably, in step (2), the spin coating speed is 1500 to 2500 rpm.

[0028] Further preferably, in step (2), the spin coating speed is 1500-2000 rpm.

[0029] More preferably, in step (2), the spin coating speed is 2000 rpm.

[0030] Preferably, in step (2), the light intensity of the light curing is 10 to 100 mW / cm 2 , time is 1 to 10 minutes.

[0031] Further preferably, in step (2), the light intensity of the light curing is 50 to 100 mW / cm 2 , time is 1 to 5 minutes.

[0032] More preferably, in step (2), the light intensity of the light curing is 50 mW / cm 2 , time is 3min.

[0033] Preferably, in step (2), the annealing temperature is 50-80° C. and the time is 0.5-2 h.

[0034] Further preferably, in step (2), the annealing temperature is 55-65° C. and the time is 1-2 h.

[0035] More preferably, in step (2), the annealing temperature is 60° C. and the time is 1 h.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] The present invention prepares structural color film by physical processing, effectively reduces environmental pollution, reduces production costs and improves resource utilization, and meets the requirements of sustainable development. The low absorption characteristics of the film significantly reduce heat accumulation, and the color can be flexibly adjusted by optimizing the parameters of the structural color layer. In addition, the brightness of the color film can be adjusted by adjusting the voltage to adjust the transmittance of the intermediate dimming layer, achieving precise adjustment on demand, high color stability and adjustable brightness, and has high practicality and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a model diagram of a structural color film prepared in Example 1 of the present invention;

[0039] Figure 2 The transmission spectra of the dimming layer under different voltages of Example 1 of the present invention;

[0040] Figure 3Brightness photos of the structural color film prepared in Example 1 of the present invention at different voltages;

[0041] Figure 4 This is a graph showing the saturation variation of the structural color film prepared in Example 1 of the present invention at different voltages;

[0042] Figure 5 This is a graph showing the brightness change of the structural color film prepared in Example 1 of the present invention under different voltages;

[0043] Figure 6 This is a color change diagram of the structural color film prepared in Example 1 of the present invention at a voltage of 45V;

[0044] Figure 7 This is an infrared camera image of the structural color film prepared in Comparative Example 1;

[0045] Figure 8 This is an infrared camera image of the structural color film prepared in Example 1 of the present invention;

[0046] Fig. 9 The light transmission performance results of the structural color films prepared in Example 1 and Comparative Example 2 of the present invention are shown in FIG.

[0047] Fig.10 This is a graph showing the color brightness changes of the structural color film prepared in Comparative Example 2. DETAILED DESCRIPTION

[0048] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0049] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0050] Example 1

[0051] A brightness-adjustable structural color film and a preparation method thereof.

[0052] The brightness-adjustable structural color film consists of a structural color layer, a dimming layer, and a reflective layer from top to bottom. The structural color layer is formed by alternating stacks of silicon dioxide and titanium dioxide, with thicknesses of 136 / 56 / 46 / 87 / 56 / 84 / 56 / 87 / 64 / 101 / 62 / 107 / 70 / 98 / 68nm, respectively, and a total thickness of 1178nm.

[0053] The dimming layer is a PDLC film with a thickness of 0.5mm;

[0054] The reflective layer is a polished high-reflective aluminum sheet with a reflectivity of 98% and a thickness of 2mm.

[0055] Preparation method:

[0056] (1) Silicon dioxide and titanium dioxide are alternately stacked by evaporation deposition to form a structural color layer;

[0057] (2) Disperse liquid crystal and polymer (PMMA) in a dichloromethane solvent in a ratio (liquid crystal: polymer = 70:30) and stir for 2 hours to disperse them on a transparent ITO substrate. Spin coating is performed with a rotation speed of 2000 rpm to coat a uniform film. Irradiate the film with 365 nm ultraviolet light at an intensity of 50 mW / cm 2 The curing time is 3 minutes. The film is annealed at 60°C for 1 hour to optimize the liquid crystal arrangement to obtain a dimming layer;

[0058] (3) The reflective layer, the dimming layer, and the structural color layer are stacked from bottom to top to obtain a structural color film.

[0059] Example 2

[0060] A brightness-adjustable structural color film and a preparation method thereof.

[0061] The difference from Example 1 is that the structural color layer is formed by alternating stacking of silicon dioxide and titanium dioxide, the thickness of each layer is 60 / 344 / 40 / 67 / 134 / 84 / 44 / 70 / 200 / 84 / 53 / 314 / 93 / 85 / 40 / 84 / 154 / 93 / 328 / 82 / 148 nm, and the total thickness of the structural color layer is 2601 nm.

[0062] The preparation method is the same as that in Example 1.

[0063] Comparative Example 1

[0064] A brightness-adjustable structural color film and a preparation method thereof.

[0065] The difference from Example 1 is that the reflective layer is a gray base sheet with a reflectivity of 74%.

[0066] The preparation method is the same as that in Example 1.

[0067] Comparative Example 2

[0068] A brightness-adjustable structural color film and a preparation method thereof.

[0069] The difference from the first embodiment is that the thickness of the dimming layer is 1.5 mm.

[0070] The preparation method is the same as that in Example 1.

[0071] like Figure 2 As shown, the transmittance data of the visible near infrared of the PDLC film in Example 1 at different voltages were measured using an optical transmittance meter. When the voltage was changing, the transmittance of the PDLC film changed significantly with the voltage. The transmittance of the film showed a change of 0 to 85% under a voltage of 0 to 60V.

[0072] like Figure 3 As shown, with the increase of voltage, the brightness of the structural color film (blue film) prepared in Example 1 is significantly reduced, and when the voltage increases to a maximum value of 60V, the structural color film appears dark blue because the PDLC film is in a maximum transmittance state at this time.

[0073] like Figure 4 As shown, the structural color film prepared in Example 1 can maintain 100% saturation in the voltage range of 0 to 30 V as the voltage increases. After the voltage continues to increase, the saturation begins to decrease, mainly because the transmittance of PDLC decreases, the scattering of the transmitted light is enhanced, and the non-blue light components mixed into the unit space increase, thereby reducing the color saturation.

[0074] like Figure 5 As shown, the brightness value B of the structural color of the structural color film obtained in Example 1 decreases with the increase of voltage. The brightness value can reach a maximum of 95% and a minimum of 43% under the voltage range of 0 to 60V. The trend of decreasing brightness during the increase of voltage is consistent with the trend of decreasing transmittance of the PDLC film. As the transmittance decreases, the degree of scattering increases, the spatial range of the blue light component distribution increases, the blue light intensity per unit space decreases, and the brightness of the color is reduced.

[0075] like Figure 7 As shown, the structural color film prepared in Comparative Example 1 has a low reflectivity of the reflective layer, and the light transmitted from the top layer will be absorbed by the reflective layer. Therefore, under the infrared camera, the gray base film shows a temperature of 37°C, while Figure 8 As shown, the film of Example 1 of the present invention using a high-reflective aluminum sheet as a substrate has a temperature of only 29.7° C. under an infrared camera.

[0076] like Fig. 9 As shown, the structural color film prepared in Comparative Example 2 will affect the light transmission performance because the dimming layer in the middle is too thick. Fig. 9 (a) is a structural color film with a 0.5 mm dimming layer according to Example 1 of the present invention. When a voltage of 60 V is applied, the transmittance of the dimming layer is obviously high, and objects at the bottom can be seen. Fig. 9 (b) is a structural color film prepared in comparative example 2. When the dimming layer is too thick to reach 1.5 mm, the transmittance of the dimming layer at 60 V voltage is significantly reduced. Fig.10As shown, the structural color film prepared in Comparative Example 2 has a too thick dimming layer, and the transmittance change is low within the voltage control range of 0 to 60 V, so the overall blue film color brightness has almost no adjustment effect.

[0077] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution obtained by any modification, equivalent replacement, improvement, etc. made by a person skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection determined by the claims.

Claims

1. A brightness-adjustable structural color film, characterized in that: The structural color film has a three-layer structure; The three-layer structure includes, from top to bottom, a structural color layer, a dimming layer, and a reflective layer; The reflective layer includes at least one of aluminum sheet, silver mirror, polytetrafluoroethylene, and white paint sheet; The thickness of the dimming layer is 0.2-1 mm.

2. The structural color film according to claim 1, characterized in that: The thickness of the structural color layer is 1000-3000nm.

3. The structural color film according to claim 1, characterized in that: The material of the structural color layer includes at least one of SiO2, ZrO2, Al2O3, TiO2, and Ta2O5.

4. The structural color film according to claim 1, characterized in that: The thickness of the reflective layer is 0.1-2 mm.

5. The structural color film according to claim 1, characterized in that: The material of the dimming layer includes any one of a nematic liquid crystal material, a liquid dispersion of titanium dioxide particles, and a liquid dispersion of zinc oxide particles.

6. The structural color film according to claim 1, characterized in that: The reflectivity of the reflective layer is 85-98%.

7. The method for preparing a structural color film according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) The materials of the structural color layer are alternately stacked by physical deposition to form a structural color layer; (2) dispersing the material of the dimming layer on the substrate, spin coating, photocuring, and annealing to obtain the dimming layer; (3) The reflective layer, the dimming layer, and the structural color layer are stacked from bottom to top to obtain a structural color film.

8. The preparation method according to claim 7, characterized in that: In step (1), the physical deposition method includes evaporation deposition and magnetron sputtering.

9. The preparation method according to claim 7, characterized in that: In step (2), the rotation speed of the spin coating is 1500 to 2500 rpm.

10. The preparation method according to claim 7, characterized in that: In step (2), the light intensity of the light curing is 10 to 100 mW / cm 2 , time is 1 to 10 minutes.

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