Structure-pigment color film capable of changing color in force-heat dual stimulation response mode and preparation method and application of structure-pigment color film

Abstract

The invention provides a force-heat dual stimulation response color-changing structure-pigment color film as well as a preparation method and application thereof, and belongs to the technical field of intelligent windows and color-changing films. Structural color generated by a spherical nanoparticle-matrix in the stretching process is utilized, that is, refractive indexes of original nanoparticles and matrixes are matched and transparent, but air introduced by wrinkles, cracks or holes generated in the stretching process causes a new reflection interface (namely gaps / nanoparticles and gaps / matrixes), the reflectivity on the interface is sharply increased, and the reflection effect is improved. The light transmittance of the film is reduced and structural color is generated. The thermochromic microcapsule is utilized to generate pigment color under the temperature change. The film provided by the invention has force-heat dual responsiveness, can be used for preparing a force-heat dual response type intelligent window, effectively solves the problem that an existing intelligent film and an intelligent window thereof can only make single stimulation response to force or temperature change, and provides a new solution for high performance and multi-functionalization of the intelligent window.

Description

Technical Field

[0001] The present invention belongs to the technical fields of intelligent windows and color-changing films, and particularly relates to a structure-pigment color film with force-thermal dual-stimulus response color change, a preparation method thereof, and an application thereof. Background Art

[0002] Intelligent films that respond to color change based on different environmental factor stimuli and their applications in intelligent windows have been a research hotspot in recent years. This is because they can adjust the indoor thermal environment as needed by adjusting the optical properties in different bands (ultraviolet-visible-near infrared), thereby reducing the energy consumption of air conditioning heating / cooling. The latest developments in intelligent color-changing film technology can be mainly divided into electrochromism, thermochromism, mechanochromism, photochromism, and solvatochromism, etc. Among them, thermochromism is a color-changing behavior that responds to stimuli based on changes in environmental temperature factors and belongs to passive control. Generally speaking, the research on thermochromic films is relatively in-depth at present. The biggest advantage of thermochromic microcapsules (TCMs) with visible light band (visible to the naked eye) thermochromism as thermochromic materials lies in the customization of color and color-changing temperature, and its color is pigment color. Compared with inorganic thermochromic materials (such as vanadium dioxide) whose optical performance changes are invisible to the naked eye, the thermochromic effect of TCMs will be more intuitive and practical.

[0003] Mechanochromic intelligent windows are a new type of intelligent window that emerged in recent years and can adjust optical properties through simple mechanical strain. Compared with traditional thermochromic intelligent films, it has the characteristics of active control, low cost, and fast response speed, and its matrix material generally also selects elastic polymers. Nano-particle (NPs)-matrix composites are an effective strategy to achieve mechanochromism. This strategy will produce visible structural colors during the stretching process and will change the optical properties in the ultraviolet-visible-near infrared bands.

[0004] With the development of intelligent films and intelligent window applications that respond to color change based on environmental stimuli, in recent years, intelligent windows prepared with single-mode color-changing films that only play an energy-saving role can no longer meet the requirements of the multi-functionalization of intelligent windows. Compared with single-mode color-changing intelligent windows, multi-mode color-changing intelligent windows have more modes for users to choose. The development of force-thermal dual-stimulus response color-changing intelligent films and their intelligent windows is in its infancy, and currently, the products on the market can basically only make a single stimulus response to force or temperature alone. Summary of the Invention

[0005] The present invention is made to solve the above problems, and aims to provide a structure-pigment color film with force-thermal dual-stimulus response color change, a preparation method thereof, and an application thereof.

[0006] The present invention provides a method for preparing a structure-pigment color film with force-thermal dual-stimulus response color change, having the following characteristics, including the following steps: S10, uniformly spraying a dispersion of spherical nanoparticles on the inner bottom of a container, and obtaining a self-assembled spherical nanoparticle structure after the liquid in the dispersion volatilizes; S20, pouring a first mixture obtained by mixing polydimethylsiloxane, a curing agent, and solvent B into the container and controlling the liquid level, and heating for pre-curing so that the first mixture penetrates into the voids of the self-assembled spherical nanoparticle structure; S30, before the first mixture in the container in step S20 is completely cured, pouring a second mixture obtained by mixing polydimethylsiloxane, a curing agent, thermochromic microcapsules, and solvent B into the container and controlling the liquid level, and heating until solvent B completely volatilizes and curing to obtain a structure-pigment color film with force-thermal dual-stimulus response color change, wherein the thermochromic microcapsules are of a core-shell structure, the material of the core structure of the thermochromic microcapsules includes a phenolic color developer, a fluoran leuco dye, and a long straight-chain higher carbon alcohol solvent, and the material of the shell structure of the thermochromic microcapsules includes melamine formaldehyde resin.

[0007] In the method for preparing a structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may also have the following characteristics: wherein, step S10 includes the following sub-steps: S11, dispersing silica and / or polystyrene as spherical nanoparticles in solvent A and ultrasonically dispersing to obtain a dispersion of spherical nanoparticles; S12, spraying the dispersion of spherical nanoparticles on the inner bottom of the container through a spray gun in a cyclic and reciprocating manner and uniformly covering; S13, obtaining a self-assembled spherical nanoparticle structure after solvent A completely volatilizes.

[0008] In the method for preparing a structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may also have the following characteristics: wherein, in step S11, the average particle size of the spherical nanoparticles is 100 nm to 800 nm, the polydispersity index is 0 to 0.1, solvent A includes ethanol and / or isopropanol, the content of spherical nanoparticles in the dispersion is 3 wt% to 15 wt%, the ultrasonic time is 1 h to 3 h, in step S12, the nozzle size of the spray gun is 0.1 mm to 0.8 mm, the working pressure is 30 kPa to 70 kPa, the moving rate is 5 cm / s to 15 cm / s, the spraying distance is 5 cm to 15 cm, spraying in a cyclic and reciprocating manner for 5 to 50 cycles and uniformly spraying 3 to 6 times per cycle, the container is a petri dish, and in step S13, the thickness of the self-assembled spherical nanoparticle structure is 1 μm to 15 μm.

[0009] In the method for preparing a structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may also have the following characteristics: wherein, solvent B includes any one or more of acetone, n-hexane, cyclohexane, n-heptane, ethyl acetate, or butyl acetate.

[0010] In the method for preparing the structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may further have the following characteristics: wherein, step S20 includes the following sub-steps: S21, stirring and mixing polydimethylsiloxane and a curing agent, and then removing air bubbles under vacuum to obtain a mixed solution I; S22, mixing the mixed solution I with solvent B to obtain a first mixed solution; S23, pouring the first mixed solution into a container and controlling the liquid level, and heating for pre-curing so that the first mixed solution penetrates into the voids of the self-assembled spherical nanoparticle structure.

[0011] In the method for preparing the structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may further have the following characteristics: wherein, in step S21, the mass ratio of polydimethylsiloxane to the curing agent is (80-95) wt%:(5-20) wt%, the stirring time is 20 min to 50 min, the stirring rate is 25 rpm to 180 rpm, the vacuum degassing time is 20 min to 60 min, in step S22, the mass ratio of the mixed solution I to solvent B is (70-95) wt%:(5-30) wt%, in step S23, the pre-curing method is heating at 40°C to 70°C for 15 min to 40 min. When the container is a square petri dish with a side length of 5 cm to 15 cm and the mass of the first mixed solution is 5 g to 10 g, the thickness of the casting obtained by heating and pre-curing is 150 μm to 350 μm.

[0012] In the method for preparing the structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may further have the following characteristics: wherein, step S30 includes the following sub-steps: S31, stirring and mixing polydimethylsiloxane, a curing agent, and thermochromic microcapsules, and then removing air bubbles under vacuum to obtain a mixed solution II; S32, mixing the mixed solution II with solvent B to obtain a second mixed solution; S33, before the first mixed solution in the container in step S20 is completely cured, pouring the second mixed solution into the container and controlling the liquid level, and heating until solvent B completely volatilizes to cure and obtain the structure-pigment color film with force-thermal dual-stimulus response color change.

[0013] In the method for preparing the structure-pigment color film with force-thermal dual-stimulus response color change provided by the present invention, it may further have the following characteristics: Among them, in step S31, the mass ratio of polydimethylsiloxane, curing agent, and thermochromic microcapsules is (80-95) wt%: (5-20) wt%: (0.1-2) wt%, the stirring time is 25 min to 55 min, the stirring speed is 20 rpm to 190 rpm, the vacuum degassing time is 25 min to 65 min, the thermochromic temperature range of the thermochromic microcapsules is 5°C to 70°C, and the particle size of the thermochromic microcapsules is 0.5 μm to 10 μm. In step S32, the mass ratio of the mixed solution II to the solvent B is (70-95) wt%: (5-30) wt%. In step S33, the heating and curing method is heating at 50°C to 80°C for 6 h to 30 h. When the container is a square petri dish with a side length of 5 cm to 15 cm and the mass of the second mixed solution is 5 g to 10 g, the thickness of the casting obtained by heating and curing is 150 μm to 350 μm.

[0014] The present invention also provides a structure-pigment color film with force-thermal dual-stimulus response color change, which has the following characteristics. It is prepared by the method for preparing the structure-pigment color film with force-thermal dual-stimulus response color change according to any one of the foregoing. It includes: a force-induced color change layer, including uniformly mixed spherical nanoparticles and polydimethylsiloxane; an elastic polymer layer, disposed on the force-induced color change layer, and the material is polydimethylsiloxane; and a thermochromic layer, disposed on the elastic polymer layer, and the material is uniformly mixed polydimethylsiloxane and thermochromic microcapsules.

[0015] The present invention also provides an application of the structure-pigment color film with force-thermal dual-stimulus response color change according to any one of the foregoing in a smart window.

[0016] Functions and effects of the invention

[0017] On the one hand, the present invention utilizes the structural color generated by spherical nanoparticles-matrix during the stretching process. That is, the refractive indices of the original nanoparticles and the matrix match and are transparent. However, the air introduced by the wrinkles, cracks, or voids generated during the stretching process results in new reflection interfaces (i.e., voids / nanoparticles, voids / matrix), and the reflectivity on the interfaces increases sharply. Therefore, the light transmittance of the film decreases, generating structural color. On the other hand, it utilizes the color change (pigment color) generated by the thermochromic microcapsules under temperature changes. Therefore, the film provided by the present invention has force-thermal dual responsiveness and can be used to prepare a force-thermal dual-responsive smart window, effectively solving the problem that existing smart films and their smart windows can only make a single stimulus response to force or temperature changes, and promoting the high performance and multifunctionality of smart windows.

[0018] In the process of designing materials and structures, the present invention takes into account the differences in the particle sizes of thermochromic microcapsules and silica nanoparticles. Therefore, a structure of "spherical nanoparticles / matrix - matrix - matrix / thermochromic microcapsules" is designed. The high - elasticity matrix layer in the middle not only thins due to stretching during the stretching process, but also prevents the contact between thermochromic microcapsules and spherical nanoparticles, which prevents the larger - sized thermochromic microcapsules from destroying the self - assembled structure formed by the smaller - sized spherical nanoparticles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic flow chart of a preparation method of a force - heat dual - stimulus responsive color - changing structure - pigment color film according to an embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of a force - heat dual - stimulus responsive color - changing structure - pigment color film according to an embodiment of the present invention;

[0021] Figure 3 is a schematic functional diagram of a force - heat dual - stimulus responsive color - changing structure - pigment color film according to an embodiment of the present invention;

[0022] Figure 4 is a design diagram of a force - heat dual - stimulus responsive color - changing structure - pigment color film used as a smart window according to an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of the light transmittance of Film 1, Film 2, and Film 3 in the test examples of the present invention under the coupling stimulation of 55 °C and 40% strain. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the technical means, creative features, achieved purposes, and functions of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically elaborate on a force - heat dual - stimulus responsive color - changing structure - pigment color film of the present invention, its preparation method, and applications.

[0025] <Embodiment>

[0026] Figure 1 is a schematic flow chart of a preparation method of a force - heat dual - stimulus responsive color - changing structure - pigment color film according to an embodiment of the present invention.

[0027] As Figure 1 shown, this embodiment provides a preparation method of a force - heat dual - stimulus responsive color - changing structure - pigment color film, including the following steps:

[0028] S10. Prepare a self - assembled spherical nanoparticle structure, including the following sub - steps S11 - S13:

[0029] S11, Prepare the dispersion: Disperse spherical nanoparticles with a particle size of 300 nm (polydispersity index is 0.07) into solvent A, and ultrasonically agitate at room temperature for t1 = 1 h to 3 h in an ultrasonic cleaner to obtain a dispersion of spherical nanoparticles with a mass fraction ω1 = 3 wt% to 15 wt%.

[0030] Among them, the spherical nanoparticles are spherical nano-silica; the solvent A is isopropyl alcohol.

[0031] S12, Spray the dispersion: Load the dispersion of spherical nanoparticles into a spray gun with a nozzle size of 0.3 mm, and spray it back and forth on the bottom of the container at a moving rate of 10 cm / s and a spraying distance of 10 cm under a pressure of P = 30 kPa to 70 kPa for 20 cycles. Each cycle is sprayed 4 times and evenly covers the entire bottom of the container.

[0032] Among them, the container is a square polystyrene culture dish with a side length of 10 cm.

[0033] S13, Self-assembly of spherical nanoparticles: After the solvent A quickly volatilizes, a self-assembled spherical nanoparticle structure is obtained, and its thickness is about 5 μm.

[0034] S20, Preliminarily prepare the force-responsive color-changing layer and the elastic polymer layer (containing part of solvent B), including the following sub-steps S21 to S23:

[0035] S21, Mix polydimethylsiloxane and a curing agent (control the mass fraction ω2 of polydimethylsiloxane = 80 wt% to 95 wt%), and then stir at a rate of 25 rpm to 180 rpm at room temperature for 20 min to 50 min, and remove air bubbles under vacuum for t2 = 20 min to 60 min to obtain the mixed solution Ⅰ.

[0036] S22, Mix the mixed solution Ⅰ and the solvent B according to a mass ratio of 75 wt%:25 wt% to obtain the first mixed liquid.

[0037] Among them, the solvent B includes any one or more of acetone, n-hexane, cyclohexane, n-heptane, ethyl acetate or butyl acetate (specifically selected as n-hexane in this embodiment).

[0038] S23, Pour m1 = 5 g to 10 g of the first mixed liquid into the container, and heat it in an oven at 40 °C to 70 °C for 15 min to 40 min for pre-curing so that the first mixed liquid penetrates into the voids of the self-assembled spherical nanoparticle structure, and the thickness of the obtained casting is h1 = 150 μm to 350 μm.

[0039] S30, Prepare the thermochromic layer and make the solvent B completely volatilize to form the final force-thermal dual-stimulus responsive color-changing structure-pigment color film, including the following sub-steps S31 to S34:

[0040] S31. Mix polydimethylsiloxane, a curing agent, and thermochromic microcapsules in a mass ratio of (80 - 95) wt%:(5 - 20) wt%:(0.1 - 2) wt%, stir at a stirring rate of 20 rpm to 190 rpm for 25 min to 55 min, and remove air bubbles under vacuum for t2 = 25 min to 65 min to obtain a mixed solution II.

[0041] Among them, the thermochromic microcapsules have a core - shell structure. The material of the core structure of the thermochromic microcapsules includes phenolic color developers, fluoran leuco dyes, and long - straight - chain higher - carbon - alcohol solvents. The material of the shell structure of the thermochromic microcapsules includes melamine - formaldehyde resin.

[0042] The thermochromic temperature range of the thermochromic microcapsules is 5°C to 70°C. Before color change (below the solvent phase - change temperature), they present a white state, and after color change (above the solvent phase - change temperature), they present a colored state. The particle size of the thermochromic microcapsules is 0.5 μm to 10 μm.

[0043] S32. Mix the mixed solution II and solvent B in a mass ratio of 75 wt%:25 wt% to obtain a second mixed solution.

[0044] S33. Before the first mixed solution in the container in step S20 is completely cured, pour m2 = 5 g to 10 g of the second mixed solution into the container, heat in an oven at 50°C to 80°C for 6 h to 30 h until solvent B completely volatilizes and polydimethylsiloxane cures (in this step, the thickness of the casting is h2 = 150 μm to 350 μm) to obtain a force - heat dual - stimulus responsive color - changing structure - pigment color film.

[0045] Figure 2 It is a schematic structural diagram of a force - heat dual - stimulus responsive color - changing structure - pigment color film of an embodiment of the present invention.

[0046] As Figure 2 shown, this embodiment also provides a force - heat dual - stimulus responsive color - changing structure - pigment color film 100, which is prepared by the preparation method of a force - heat dual - stimulus responsive color - changing structure - pigment color film in this embodiment.

[0047] A force - heat dual - stimulus responsive color - changing structure - pigment color film 100 of this embodiment includes a force - induced color - changing layer 10, an elastic polymer layer 20, and a thermochromic layer 30 arranged layer by layer.

[0048] The force - induced color - changing layer 10 includes uniformly mixed spherical nanoparticles 11 and polydimethylsiloxane PDMS.

[0049] The material of the elastic polymer layer 20 is polydimethylsiloxane PDMS.

[0050] The material of the thermochromic layer 30 is a homogeneous mixture of polydimethylsiloxane PDMS and thermochromic microcapsules TCM.

[0051] In the structure-pigment color film 100 with force-thermal dual-stimulus responsive color change, the elastic polymer layer 20 between the force-responsive layer 10 and the thermochromic layer 30 mainly prevents the contact between the thermochromic microcapsules TCM and the spherical nanoparticles 11, and prevents the thermochromic microcapsules TCM with larger particle sizes from destroying the self-assembled structure formed by the spherical nanoparticles 11 with smaller particle sizes.

[0052] This embodiment also provides an application of the structure-pigment color film with force-thermal dual-stimulus responsive color change in intelligent windows.

[0053] Figure 3 It is a functional schematic diagram of the structure-pigment color film with force-thermal dual-stimulus responsive color change according to the embodiment of the present invention. As Figure 3 shown, the structure-pigment color film with force-thermal dual-stimulus responsive color change in this embodiment is in the normal mode under normal conditions. At this time, the film has a strong light transmittance in the visible and near-infrared bands, and users can see the outside world through the film. In the case of only temperature stimulation, the thermochromic microcapsules play a role, and the color of the film changes (pigment color), and it is in the colored mode. At this time, the light transmittance of the film in the visible light band decreases, and the outside world seen by the user has a layer of color. In the case of only strain stimulation, the nanoparticle-matrix structure plays a role, the reflectivity of the film increases, and the structural color generated by the structure is seen by the user. The light transmittance in both the visible and near-infrared bands decreases at the same time, and the haze of the film increases. At this time, the film is in the privacy mode. As the strain increases, it becomes gradually impossible to see through the film from one side to the other side. In the case of coupled temperature and strain stimulation, both the thermochromic microcapsules and the nanoparticle-matrix structure play a role, and the light transmittance of the film in all bands decreases. At this time, the film is in the energy-saving mode, and the light modulation ability in this mode is the strongest.

[0054] Figure 4 It is a design drawing of the structure-pigment color film with force-thermal dual-stimulus responsive color change according to the embodiment of the present invention used as an intelligent window.

[0055] As Figure 4 shown, one end of the structure-pigment color film with force-thermal dual-stimulus responsive color change in this embodiment is fixed and sandwiched between two pieces of glass, and it is gradually stretched under an external force to change the optical transmittance in different bands. In addition, it can also sense the temperature of the environment and produce color changes.

[0056] <Test Example>

[0057] Three force-thermal dual-stimulus responsive structural-photonic color films were prepared according to the preparation method of a force-thermal dual-stimulus responsive structural-photonic color film provided by the embodiment, and were respectively denoted as Film 1, Film 2, and Film 3.

[0058] The specific parameters in the preparation processes of Film 1, Film 2, and Film 3 are shown in Table 1 below.

[0059] Table 1 (Specific parameters in the preparation processes of Film 1, Film 2, and Film 3)

[0060]

[0061] Figure 5 It is a schematic diagram of the transmittance of Film 1, Film 2, and Film 3 of the test example of the present invention under the coupling stimulation of 55 °C and 40% strain.

[0062] As shown in Table 1 and Figure 5 As shown, as the mass fraction of the thermochromic microcapsules increases, the colors of the films stretched by 40% gradually change from colorless to black at 25 °C and 55 °C, and the "Tongji University logo" behind the films becomes gradually blurred due to the stretching (force-responsive layer) and the increase in the mass fraction of the thermochromic microcapsules.

[0063] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a structure-pigment color film with force-thermal dual-stimulus response color change, characterized in that, It includes the following steps: S10, uniformly spraying the dispersion of spherical nanoparticles on the inner bottom of a container, and obtaining a self-assembled spherical nanoparticle structure after the liquid in the dispersion volatilizes; S20, pouring a first mixed solution obtained by mixing polydimethylsiloxane, a curing agent, and solvent B into the container and controlling the liquid level, and heating for pre-curing so that the first mixed solution penetrates into the voids of the self-assembled spherical nanoparticle structure; S30, before the first mixed solution in the container in step S20 is completely cured, pouring a second mixed solution obtained by mixing polydimethylsiloxane, a curing agent, thermochromic microcapsules, and solvent B into the container and controlling the liquid level, and heating until solvent B completely volatilizes, and curing to obtain a force- and heat-dual-stimulus responsive color-changing structure-pigment color film, wherein, the thermochromic microcapsules are of a core-shell structure, the material of the core structure of the thermochromic microcapsules includes phenolic color developers, fluoran leuco dyes, and long straight-chain higher carbon alcohol solvents, and the material of the shell structure of the thermochromic microcapsules includes melamine formaldehyde resin.

2. The method for preparing a force- and heat-dual-stimulus responsive color-changing structure-pigment color film according to claim 1, wherein: Among them, Step S10 includes the following sub-steps: S11, dispersing silica and / or polystyrene as spherical nanoparticles into solvent A and ultrasonically dispersing to obtain a dispersion of spherical nanoparticles; S12, spraying the dispersion of spherical nanoparticles on the inner bottom of the container through a spray gun in a cyclic and reciprocating manner and uniformly covering; S13, obtaining a self-assembled spherical nanoparticle structure after solvent A completely volatilizes.

3. The method for preparing a force- and heat-dual-stimulus responsive color-changing structure-pigment color film according to claim 2, wherein: Among them, In step S11, the average particle size of the spherical nanoparticles is 100 nm to 800 nm, the polydispersity index is 0 to 0.1, solvent A includes ethanol and / or isopropanol, the content of the spherical nanoparticles in the dispersion is 3 wt% to 15 wt%, and the ultrasonic time is 1 h to 3 h, In step S12, the nozzle size of the spray gun is 0.1 mm to 0.8 mm, the working pressure is 30 kPa to 70 kPa, the moving rate is 5 cm / s to 15 cm / s, the spraying distance is 5 cm to 15 cm, spraying in a cyclic and reciprocating manner for 5 to 50 cycles and uniformly spraying 3 to 6 times per cycle, and the container is a petri dish, In step S13, the thickness of the self-assembled spherical nanoparticle structure is 1 μm to 15 μm.

4. The method for preparing a force- and heat-dual-stimulus responsive color-changing structure-pigment color film according to claim 1, wherein: Among them, Solvent B includes any one or more of acetone, n-hexane, cyclohexane, n-heptane, ethyl acetate, or butyl acetate.

5. The method for preparing a force- and heat-dual-stimulus responsive color-changing structure-pigment color film according to any one of claims 1 to 4, wherein: Among them, Step S20 includes the following sub-steps: S21, stirring and mixing polydimethylsiloxane and a curing agent and removing air bubbles under vacuum to obtain a mixed solution I; S22. Mix the mixed solution I with solvent B to obtain the first mixed solution. S23. Pour the first mixed solution into the container and control the liquid level, and heat for pre-curing to enable the first mixed solution to penetrate into the voids of the self-assembled spherical nanoparticle structure.

6. The method for preparing a force-thermally dual-stimulus responsive color-changing structure-pigment color film according to claim 5, wherein: Among them, In step S21, the mass ratio of polydimethylsiloxane to the curing agent is (80-95) wt%:(5-20) wt%, the stirring time is 20 min to 50 min, the stirring rate is 25 rpm to 180 rpm, and the vacuum degassing time is 20 min to 60 min. In step S22, the mass ratio of the mixed solution I to solvent B is (70-95) wt%:(5-30) wt%. In step S23, the pre-curing method is heating at 40°C to 70°C for 15 min to 40 min. When the container is a square petri dish with a side length of 5 cm to 15 cm and the mass of the first mixed solution is 5 g to 10 g, the thickness of the casting obtained by heating and pre-curing is 150 μm to 350 μm.

7. The method for preparing a force-thermally dual-stimulus responsive color-changing structure-pigment color film according to any one of claims 1 to 4, wherein: Among them, Step S30 includes the following sub-steps: S31. Stir and mix polydimethylsiloxane, the curing agent, and the thermochromic microcapsules, and then remove air bubbles under vacuum to obtain the mixed solution II. S32. Mix the mixed solution II with solvent B to obtain the second mixed solution. S33. Before the first mixed solution in the container in step S20 is completely cured, pour the second mixed solution into the container and control the liquid level, and heat until solvent B completely volatilizes to obtain a force-thermally dual-stimulus responsive color-changing structure-pigment color film by curing.

8. The method for preparing a force-thermally dual-stimulus responsive color-changing structure-pigment color film according to claim 7, wherein: Among them, In step S31, the mass ratio of polydimethylsiloxane, the curing agent, and the thermochromic microcapsules is (80-95) wt%:(5-20) wt%:(0.1-2) wt%, the stirring time is 25 min to 55 min, the stirring speed is 20 rpm to 190 rpm, the vacuum degassing time is 25 min to 65 min, the thermochromic temperature range of the thermochromic microcapsules is 5°C to 70°C, and the particle size of the thermochromic microcapsules is 0.5 μm to 10 μm. In step S32, the mass ratio of the mixed solution II to solvent B is (70-95) wt%:(5-30) wt%. In step S33, the heating and curing method is heating at 50°C to 80°C for 6 h to 30 h. When the container is a square petri dish with a side length of 5 cm to 15 cm and the mass of the second mixed solution is 5 g to 10 g, the thickness of the casting obtained by heating and curing is 150 μm to 350 μm.

9. A structure-pigment color film with force-thermal dual-stimulus response color change, characterized in that Prepared by the method for preparing a force-thermally dual-stimulus responsive color-changing structural-pigment color film according to any one of claims 1 to 8, comprising: A force-responsive color-changing layer, comprising the spherical nanoparticles and polydimethylsiloxane which are uniformly mixed; An elastic polymer layer, disposed on the force-responsive color-changing layer, and the material thereof is polydimethylsiloxane; and A thermally-responsive color-changing layer, disposed on the elastic polymer layer, and the material thereof is polydimethylsiloxane and the thermally-responsive color-changing microcapsules which are uniformly mixed.

10. Use of the force-thermally dual-stimulus responsive color-changing structural-pigment color film according to claim 9 in a smart window.

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