A preparation method and application method of low-voltage driven color-changing nanomaterial

Abstract

This application relates to the field of nanomaterial technology and specifically discloses a method for preparing a low-voltage-driven color-changing nanomaterial and its application method. The low-voltage-driven color-changing nanomaterial obtained by the preparation method of the present application not only overcomes the defects of electrically polarized color-changing optical films, which have a single color and difficulty adjusting the brightness and darkness of the color, but also overcomes the defects of electrically polarized color-changing optical films, such as slow response speed and narrow transmittance adjustment range when the driving voltage is low. Furthermore, the preparation method of the present application is sufficiently simple and controllable, making it more suitable for application in EPC smart color-changing glass and fully meeting market demand.

Description

Technical Field

[0001] The present application relates to the field of nanomaterial technology, and more specifically, to a preparation method and application method of a low-voltage driven color-changing nanomaterial. Background Art

[0002] Electrochromic glass, a new type of smart glass, can switch between bright and dark states under the influence of an applied electric field. It offers numerous functions, including light-blocking, heat insulation, energy conservation, and privacy. It is widely used in smart homes, offices, buildings, automobiles, high-speed rail, and other fields. In the past, smart glass based on electrochromic technology primarily consisted of polymer-dispersed liquid crystal (PDLC) and conductive polymer electrochromic (EC) glass. In recent years, electrically polarized crystal (EPC) smart color-changing glass has begun to gain popularity. The core of this type of glass is an electrically polarized optical film containing electrically polarized crystal particles. When power is applied, the electrically polarized crystal particles within the film align in a directional manner, allowing light to pass through. At this point, the film is in the bright state. When power is removed, the electrically polarized crystal particles within the film return to their disordered distribution due to Brownian motion, causing the film to be in the dark state.

[0003] In the related art, there is an electrically polarized color-changing optical film, which is prepared according to the following steps: (1) mixing electrically polarized crystal particles and polyoctyl methacrylate, then adding dichloromethane and ultrasonically dispersing, and then drying by spin drying to obtain a first emulsion; adding a photocuring initiator to a polyacrylate polystyrene copolymer with a viscosity of 12000 cps, adding acetone, stirring, and then drying by spin drying to obtain a second emulsion; (2) blending the first emulsion and the second emulsion, stirring and vacuum degassing to obtain a coating slurry; (3) coating the coating slurry between two layers of ITO conductive film, cross-linking and curing under ultraviolet light, to obtain an electrically polarized color-changing optical film. The preparation principle of the above-mentioned electrically polarized crystal particles is: first, iodine salt is adsorbed into titanium dioxide nanotubes, then the titanium dioxide nanotubes are amino-modified, and then the iodine salt is oxidized to elemental iodine using chlorine gas, and finally, the dye is grafted onto the carbon nanotubes through the amino group to obtain electrically polarized particles.

[0004] Regarding the above-mentioned related technologies, the inventors believe that the electrically polarized color-changing optical films in the related technologies are difficult to have a faster color change response speed and a larger transmittance adjustment range under lower driving voltage conditions, and the colors presented by the electrically polarized color-changing optical films are greatly restricted. In addition to the defect of a single color, it is also difficult to adjust the brightness of the color, and it cannot fully meet market demand. Summary of the Invention

[0005] In the related art, electrically polarized color-changing optical films struggle to achieve a fast color change response speed and a wide transmittance adjustment range under low driving voltage conditions. Furthermore, the films only display a single color, making it difficult to adjust the brightness and darkness of the color, thus failing to fully meet market demand. To address these deficiencies, this application provides a method for preparing a low-voltage-driven color-changing nanomaterial and its application.

[0006] In a first aspect, the present application provides a method for preparing a low-voltage driven color-changing nanomaterial, using the following technical solution:

[0007] A method for preparing a low-voltage driven color-changing nanomaterial comprises the following steps:

[0008] (1) using an amine compound as a solvent, preparing an M solution containing a metal salt as a solute and an S solution containing a sulfiding agent as a solute, and setting them aside; the metal element contained in the metal salt includes at least one of cerium, samarium, indium, manganese, copper, antimony, zirconium, bismuth, rhenium, tungsten, cobalt, and molybdenum; the sulfiding agent is sulfur or an organic sulfur compound, and the organic sulfur compound is at least one of thiophenol, thioether, and thiol; and the molar ratio of the sulfur element in the S solution to the metal element in the M solution is (3.5-10):2;

[0009] (2) heating one of the S solution and the M solution to 140-220° C., then adding the other solution, starting the timing and carrying out the heat-insulating reaction, adding a surfactant within 0.5-1.5 hours after the start of the reaction, cooling and terminating the reaction after the reaction time reaches 1-5 hours, and obtaining a reaction solution, wherein the surfactant is added at least 10 minutes before the cooling and terminating the reaction; the order of adding the S solution and the M solution is: when the sulfiding agent is an organic sulfur compound, the S solution is added to the M solution; when the sulfiding agent is elemental sulfur, the M solution is added to the S solution;

[0010] (3) The reaction liquid is ultrasonically dispersed, and then the amine compounds in the reaction liquid are removed by centrifugation. The solid residue is added to an alkane solvent for dispersion, and then the alkane solvent is removed by centrifugation to obtain a new solid residue. The new solid residue is washed to obtain a low-voltage driven color-changing nanomaterial.

[0011] By adopting the above technical solution, the present application uses an amine compound as a solvent to prepare an S solution and an M solution respectively, and then reacts the metal salt in the S solution with the sulfiding agent in the M solution under specific conditions to obtain a nanoscale metal sulfide containing at least one element of cerium, samarium, indium, manganese, copper, antimony, zirconium, bismuth, rhenium, tungsten, cobalt, and molybdenum, that is, a low-voltage driven color-changing nanomaterial. The surface of the low-voltage driven color-changing nanomaterial carries an electric charge, so it can be used as an electrically polarized crystal particle in an electrically polarized color-changing optical film. Under the preparation conditions specified in the present application, the low-voltage driven color-changing nanomaterial is mainly rod-shaped, has a unique microscopic morphology and charge distribution, is easily oriented under the action of an electric field, and can also exhibit a faster color change response speed and a larger transmittance adjustment range in the electrically polarized color-changing optical film under low driving voltage. At the same time, the unique microscopic morphology also enables the low-voltage driven color-changing nanomaterial to present a variety of different colors. When the low-voltage driven color-changing nanomaterial contains cerium, samarium, and indium, it mainly presents red; when the low-voltage driven color-changing nanomaterial contains manganese, it mainly presents green; when the low-voltage driven color-changing nanomaterial contains copper, antimony, zirconium, bismuth, rhenium, tungsten, cobalt, and molybdenum, it mainly presents black. By controlling the proportions of the above three types of metal elements and then adding blue molybdenum blue in a certain proportion, not only can various colors be combined within the RGB color space, but the brightness of the color can also be adjusted by changing the depth of black. In summary, the low-voltage driven color-changing nanomaterial prepared according to the method of the present application can not only overcome the defects of the single color of the polarized color-changing optical film and the difficulty in adjusting the brightness and darkness of the color, but also overcome the defect of the slow response speed of the polarized color-changing optical film when the driving voltage is low. In addition, the preparation method of the present application is simple and controllable enough, so it is more suitable for application in EPC smart color-changing glass and can fully meet market demand.

[0012] Preferably, the amine compound is at least one of aniline, diphenylamine, dodecylamine, cyclohexylamine, oleylamine, pyridine and o-phenylenediamine.

[0013] By adopting the above technical solution, the present application further optimizes the amine compounds, and the use of the above-mentioned types of amine compounds can realize the preparation of low-voltage driven color-changing nanomaterials.

[0014] Preferably, the organic sulfur compound is at least one of p-toluenethiophenol, methyl allyl trisulfide, thiourea, guanylthiourea, allylthiourea, and 1,3-diethylthiourea.

[0015] By adopting the above technical solution, the present application further optimizes the organic sulfur compounds. The above organic sulfur compounds all have thiol groups, thioether groups or thiourea groups that can participate in the reaction, so they can all be used as vulcanizing agents, which can realize the preparation of low-voltage driven color-changing nanomaterials.

[0016] Preferably, the surfactant is at least one of Triton X-100, oleic acid, Span, Tween, ethanedithiol, 1,3-propanedithiol, 1-hexanethiol, 1,6-hexanedithiol, cyclohexanethiol, and n-dodecyl mercaptan, and the molar ratio between the surfactant and the metal element in the metal compound is (5-30):1.

[0017] By adopting the above technical solution, the present application further optimizes the surfactant. Within the above molar ratio range, the above surfactant can be used to achieve the preparation of low-voltage driven color-changing nanomaterials.

[0018] Preferably, when the total insulation reaction time of the S solution and the M solution is 1 hour, and the surfactant includes a thiol compound, the surfactant is added 10-30 minutes before the reaction is cooled to end.

[0019] By adopting the above technical solution, the present application preferably adds a surfactant when the total reaction time is 1 hour. Due to the short total reaction time, if the thiol compound is added too early, it will react with the metal compound, interfering with the preparation of the low-voltage-driven color-changing nanomaterial. However, controlling the timing of adding the surfactant 10-30 minutes before the temperature drops to the end of the reaction can improve the dispersion effect of the low-voltage-driven color-changing nanomaterial, reduce particle agglomeration, and help shorten the color change response time of the low-voltage-driven color-changing nanomaterial.

[0020] Preferably, the metal salt includes at least one of chloride, bromide, iodide, and organic acid salt.

[0021] By adopting the above technical solution, the present application optimizes the metal salt, and the selection of the above type of metal salt can realize the preparation of low-voltage driven color-changing nanomaterials.

[0022] Preferably, the metal salt includes an organic acid salt, and the organic acid salt includes at least one of indium acetate, samarium acetate, manganese acetate, manganese oxalate, molybdenum neodecanoate, copper isooctanoate, tungsten oxalate, cobalt oleate, and zirconium isooctanoate.

[0023] By adopting the above technical solution, the present application optimizes the organic acid salt, and the selection of the above type of organic acid salt can realize the preparation of low-voltage driven color-changing nanomaterials.

[0024] Preferably, the metal element contained in the metal salt includes antimony.

[0025] By adopting the above-mentioned technical solution, the present application preferably selects antimony as one of the metal elements contained in the metal salt. The addition of antimony can improve the aspect ratio of the low-voltage driven color-changing nanomaterial, which helps to obtain a low-voltage driven color-changing nanomaterial with a faster response speed in the electrically polarized color-changing optical film.

[0026] Preferably, the metal elements contained in the metal salt are bismuth and antimony, and the molar ratio between the bismuth element and the antimony element in the metal salt is 10:1.

[0027] By adopting the above technical solution, the present application prefers antimony and bismuth as the metal elements in the metal salt and limits the molar ratio of the two elements, which helps to obtain a low-voltage driven color-changing nanomaterial with a faster response speed in the polarized color-changing optical film.

[0028] In a second aspect, the present application provides an application method of a low-voltage driven color-changing nanomaterial, which adopts the following technical solution.

[0029] A method for applying a low-voltage driven color-changing nanomaterial comprises the following steps:

[0030] (1) mixing any of the above-mentioned low-voltage driven color-changing nanomaterials and polymethacrylate with a viscosity of 3000-5000 cps in a weight ratio of 1:(2-50), adding an organic solvent to the mixture and ultrasonically dispersing the mixture, and then drying the organic solvent to obtain a first emulsion; adding a photocuring initiator and an organic solvent to a UV-crosslinkable copolymer with a viscosity of 7000-12000 cps, stirring, and drying the organic solvent to obtain a second emulsion; the UV-crosslinkable copolymer is one of a polyacrylate-polystyrene copolymer and a polyacrylate-polysiloxane copolymer; and the weight of the photocuring initiator is equivalent to 0.1-3% of the weight of the UV-crosslinkable copolymer;

[0031] (2) blending the first emulsion and the second emulsion, stirring and vacuum degassing to obtain a coating slurry;

[0032] (3) The coating slurry is coated between two ITO conductive film layers, and cross-linked and cured under ultraviolet light to obtain an electrochromic optical film.

[0033] By adopting the above-mentioned technical solution, the present application uses low-voltage-driven color-changing nanomaterials as electrically polarized crystal particles, mixes them with polymethacrylate and a UV-crosslinkable copolymer, and then produces an electrically polarized color-changing optical film after coating and UV-curing. The electrically polarized color-changing optical film of the present application fully demonstrates the characteristics of low-voltage-driven color-changing nanomaterials, such as short color change response time and wide transmittance adjustment range under low-voltage conditions. Moreover, by changing the materials used in the preparation of the low-voltage-driven color-changing nanomaterials, a wide range of colors can be selected within the RGB color space, and the brightness of the color can be adjusted by adjusting the depth of black. This overcomes the shortcomings of related technologies and can more fully meet market demand.

[0034] In summary, this application has the following beneficial effects:

[0035] 1. The low-voltage driven color-changing nanomaterial prepared according to the method of the present application can not only overcome the defects of the electrically polarized color-changing optical film having a single color and difficulty in adjusting the brightness of the color, but also overcome the defect of the electrically polarized color-changing optical film having a slow response speed when the driving voltage is low. In addition, the preparation method of the present application is simple and controllable enough, so it is more suitable for application in EPC smart color-changing glass and can fully meet market demand.

[0036] 2. The present application further optimizes the amount of surfactant used, and can obtain a low-voltage driven color-changing nanomaterial with a faster response speed in the electrochromic optical film.

[0037] 3. The electrically polarized color-changing optical film of the present application fully utilizes the characteristics of low-voltage driven color-changing nanomaterials, which have short color change response time and large transmittance adjustment range under low voltage conditions. Moreover, by changing the preparation materials of the low-voltage driven color-changing nanomaterials, a wide range of selection can be made in the RGB color space, and the brightness of the color can be adjusted by the depth of black, which overcomes the defects in the relevant technology and can more fully meet market demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is an SEM image of the low-voltage driven color-changing nanomaterial of Example 1 of the present application.

[0039] Figure 2 This is an SEM image of the low-voltage driven color-changing nanomaterial of Example 4 of the present application.

[0040] Figure 3 This is an SEM image of the low-voltage driven color-changing nanomaterial of Example 6 of the present application.

[0041] Figure 4 This is an SEM image of the low-voltage driven color-changing nanomaterial of Example 8 of the present application.

[0042] Figure 5 This is an SEM image of the low-voltage driven color-changing nanomaterial of Comparative Example 5 of the present application.

[0043] Figure 6 This is an SEM image of the low-voltage driven color-changing nanomaterial of Comparative Example 9 of the present application. DETAILED DESCRIPTION

[0044] The present application is further described in detail below with reference to the Examples, Preparation Examples and Comparative Examples. The raw materials involved in the present application can all be obtained commercially.

[0045] Example

[0046] Examples 1-5

[0047] The following description will be made using Example 1 as an example.

[0048] Example 1

[0049] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0050] (1) Dispersing the sulfiding agent in a solvent at a weight ratio of 1:8, and passing nitrogen gas for 15 minutes under heating conditions of 120°C to remove dissolved oxygen, and cooling to obtain an S solution for standby use; dispersing the metal compound in a solvent at a weight ratio of 1:8, and passing nitrogen gas for 15 minutes under heating conditions of 120°C to remove dissolved oxygen, and cooling to obtain an M solution for standby use; in this step, the metal compound is a metal salt, and the metal salt is specifically prepared by mixing samarium chloride, cerium chloride, and indium acetate in a molar ratio of 1:1:1; the sulfiding agent is elemental sulfur; the molar ratio of the metal element in the metal compound to the sulfur element in the sulfiding agent is 2:3.5; both the S solution and the M solution are prepared using aniline as a solvent;

[0051] (2) heating the S solution to 140° C., and then adding the M solution dropwise to the S solution within 30 minutes. After the addition is completed, the timing is started, and the heat preservation reaction is carried out. A surfactant is added in the middle of the reaction. When the heat preservation reaction time reaches 1 hour from the start of the timing, the temperature is lowered and the reaction is terminated to obtain a reaction solution. In this step, the surfactant is added dropwise 10 minutes before the temperature is lowered and the reaction is terminated. The surfactant is prepared by mixing ethanedithiol and 1-hexanethiol in a molar ratio of 1:1, and the molar ratio between the surfactant and the metal element in the metal compound is 5:1.

[0052] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 30 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage-driven color-changing nanomaterial; in this step, the alkane solvent was isopentane.

[0053] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0054] (1) mixing a low-voltage-driven color-changing nanomaterial and polyoctyl methacrylate with a viscosity of 3000 cps in a weight ratio of 1:2, then adding tetrachloroethane to dilute it 1.5 times, and ultrasonically dispersing it at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 0.1% of the weight of the UV-crosslinkable copolymer with a viscosity of 7000 cps, adding tetrahydrofuran to dilute it 2 times and stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polystyrene copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0055] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0056] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0057] Example 2

[0058] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0059] (1) dispersing the sulfiding agent in a solvent at a weight ratio of 1:8, and passing nitrogen gas for 15 minutes under heating conditions of 120°C to remove dissolved oxygen, and cooling to obtain an S solution for standby use; dispersing the metal compound in a solvent at a weight ratio of 1:8, and passing nitrogen gas for 15 minutes under heating conditions of 120°C to remove dissolved oxygen, and cooling to obtain an M solution for standby use; in this step, the metal compound is a metal salt, and the metal salt is specifically prepared by mixing samarium acetate, cerium bromide, and indium iodide in a molar ratio of 1:1:1; the sulfiding agent is a mixture obtained by mixing guanylthiourea and p-toluenethiophenol in a molar ratio of 1:1; the molar ratio of the metal element in the metal compound to the sulfur element in the sulfiding agent is 2:4; the S solution and the M solution are both prepared using a mixture obtained by compounding diphenylamine and aniline in a weight ratio of 1:1 as a solvent;

[0060] (2) heating the S solution to 150° C., and then dripping the S solution into the M solution within 30 minutes. After the dripping is completed, the timing is started, and the heat preservation reaction is carried out. A surfactant is added in the middle of the reaction. When the heat preservation reaction time reaches 1 hour from the start of the timing, the temperature is lowered and the reaction is terminated to obtain a reaction solution. In this step, the surfactant is added 18 minutes before the temperature is lowered and the reaction is terminated. The surfactant is 1,3-propanedithiol, and the molar ratio between the surfactant and the metal element in the metal compound is 10:1.

[0061] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), respectively, and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 40 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage driven color-changing nanomaterial; in this step, the alkane solvent was a mixture of n-pentane and isopentane in a weight ratio of 1:1.

[0062] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0063] (1) mixing a low-voltage-driven color-changing nanomaterial and polyoctyl methacrylate with a viscosity of 4000 cps in a weight ratio of 1:10, then adding tetrachloroethane to dilute the mixture by 1.5 times, and ultrasonically dispersing the mixture at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 0.5% of the weight of the UV-crosslinkable copolymer with a viscosity of 8000 cps, adding tetrahydrofuran to dilute the mixture by 2 times, stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polystyrene copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0064] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0065] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0066] Example 3

[0067] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0068] (1) Dispersing the sulfiding agent in a solvent at a weight ratio of 1:8, and passing nitrogen gas for 15 minutes under heating conditions of 120°C to remove dissolved oxygen, and cooling to obtain an S solution for standby use; dispersing the metal compound in a solvent at a weight ratio of 1:8, and passing nitrogen gas for 15 minutes under heating conditions of 120°C to remove dissolved oxygen, and cooling to obtain an M solution for standby use; in this step, the metal compound is a metal salt, and the metal salt is specifically formed by mixing manganese chloride, manganese acetate, and manganese oxalate in a molar ratio of 1:1:1; the sulfiding agent is a mixture obtained by mixing methyl allyl trisulfide and allyl thiourea in a molar ratio of 1:1; the molar ratio of the metal element in the metal compound to the sulfur element in the sulfiding agent is 2:5; the S solution and the M solution are both prepared using a mixture obtained by compounding dodecylamine and aniline in a weight ratio of 1:1 as a solvent;

[0069] (2) heating the S solution to 160° C., and then dripping the S solution into the M solution within 30 minutes. After the dripping is completed, the timing is started, and the heat preservation reaction is carried out. A surfactant is added in the middle of the reaction. When the heat preservation reaction time reaches 1 hour from the start of the timing, the temperature is lowered and the reaction is terminated to obtain a reaction solution. In this step, the surfactant is added 25 minutes before the temperature is lowered and the reaction is terminated. The surfactant is 1,6-hexanedithiol, and the molar ratio between the surfactant and the metal element in the metal compound is 15:1.

[0070] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), respectively, and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 50 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage-driven color-changing nanomaterial; in this step, the alkane solvent was petroleum ether (CAS: 8032-32-4).

[0071] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0072] (1) mixing a low-voltage-driven color-changing nanomaterial and polyoctyl methacrylate with a viscosity of 5000 cps in a weight ratio of 1:20, then adding tetrachloroethane to dilute it 1.5 times, and ultrasonically dispersing it at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 1% by weight of the UV-crosslinkable copolymer with a viscosity of 10000 cps, adding tetrahydrofuran to dilute it 2 times, stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polystyrene copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0073] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0074] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0075] Example 4

[0076] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0077] (1) The sulfiding agent is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the S solution is obtained after cooling, which is used for standby; the metal compound is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the M solution is obtained after cooling, which is used for standby; in this step, the metal compound is a metal salt, and the metal salt is specifically composed of rhenium chloride, molybdenum neodecanoate, and copper isooctanoate mixed at a molar ratio of 1:1:1; the sulfiding agent is thiourea; the molar ratio of the metal element in the metal compound to the sulfur element in the sulfiding agent is 2:6; the S solution and the M solution are both prepared using a mixture obtained by compounding cyclohexylamine and aniline at a weight ratio of 1:1 as a solvent;

[0078] (2) heating the S solution to 170° C., and then dripping the S solution into the M solution within 30 minutes, starting the timing after the dripping is completed, and carrying out the heat preservation reaction. Adding a surfactant in the middle of the reaction, cooling and ending the reaction when the heat preservation reaction time reaches 2 hours from the start of the timing, and obtaining a reaction solution; in this step, the surfactant is added at 60 minutes from the start of the timing after the dripping is completed. The surfactant is a mixture of Tween 20 and Span 80 in a molar ratio of 1:1, and the molar ratio between the surfactant and the metal element in the metal compound is 20:1;

[0079] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 60 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage-driven color-changing nanomaterial; in this step, the alkane solvent was hexane.

[0080] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0081] (1) mixing a low-voltage-driven color-changing nanomaterial and polydecyl methacrylate with a viscosity of 3000 cps in a weight ratio of 1:30, then adding tetrachloroethane to dilute the mixture by 1.5 times, and ultrasonically dispersing the mixture at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 1.5% by weight of the UV-crosslinkable copolymer with a viscosity of 9000 cps, adding tetrahydrofuran to dilute the mixture by 2 times, stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polysiloxane copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0082] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0083] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0084] Example 5

[0085] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0086] (1) The sulfiding agent is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the S solution is obtained after cooling, which is set aside; the metal compound is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the M solution is obtained after cooling, which is set aside; in this step, the metal compound is a metal salt, and the metal salt is specifically formed by mixing tungsten oxalate and cobalt oleate at a molar ratio of 1:1; the sulfiding agent is 1,3-diethylthiourea; the molar ratio of the metal element in the metal compound to the sulfur element in the sulfiding agent is 2:7; the S solution and the M solution are both prepared using a mixture obtained by compounding oleylamine and pyridine at a weight ratio of 1:1 as a solvent;

[0087] (2) heating the S solution to 180° C., and then dripping the S solution into the M solution within 30 minutes, starting the timing after the dripping is completed, and carrying out the heat preservation reaction, and adding a surfactant in the middle of the reaction, cooling and ending the reaction when the heat preservation reaction time reaches 3 hours from the start of the timing, to obtain a reaction solution; in this step, the surfactant is added at 70 minutes from the start of the timing after the dripping is completed, and the surfactant is a mixture obtained by mixing n-dodecyl mercaptan and oleic acid in a molar ratio of 1:1, and the molar ratio between the surfactant and the metal element in the metal compound is 25:1;

[0088] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), respectively, and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 70 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage driven color-changing nanomaterial; in this step, the alkane solvent was a mixture of cyclohexane and isopentane in a weight ratio of 1:1.

[0089] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0090] (1) mixing a low-voltage-driven color-changing nanomaterial and polydecyl methacrylate with a viscosity of 4000 cps in a weight ratio of 1:40, then adding tetrachloroethane to dilute the mixture by 1.5 times, and ultrasonically dispersing the mixture at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 2% by weight of the UV-crosslinkable copolymer with a viscosity of 11000 cps, adding tetrahydrofuran to dilute the mixture by 2 times, stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polysiloxane copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0091] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0092] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0093] Example 6

[0094] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0095] (1) The vulcanizing agent is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the S solution is obtained after cooling, which is used for standby; the metal compound is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the M solution is obtained after cooling, which is used for standby; in this step, the metal compound is a metal salt, and the metal salt is specifically zirconium isooctanoate; the vulcanizing agent is a mixture obtained by compounding thiourea and guanylthiourea at a molar ratio of 1:1; the molar ratio of the metal element in the metal compound to the sulfur element in the vulcanizing agent is 2:8; the S solution and the M solution are both prepared using a mixture obtained by compounding o-phenylenediamine and aniline at a weight ratio of 1:1 as a solvent;

[0096] (2) heating the S solution to 190° C., and then dripping the S solution into the M solution within 30 minutes, starting the timing after the dripping is completed, and carrying out the heat preservation reaction, and adding a surfactant in the middle of the reaction, and cooling and ending the reaction when the heat preservation reaction time reaches 4 hours from the start of the timing, to obtain a reaction solution; in this step, the timing of dripping the surfactant is 85 minutes from the start of the timing after the dripping is completed, and the surfactant is a mixture obtained by mixing Triton X-100 and ethanedithiol in a molar ratio of 1:1, and the molar ratio between the surfactant and the metal element in the metal compound is 30:1;

[0097] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), respectively, and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 85 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage driven color-changing nanomaterial; in this step, the alkane solvent was a mixture of cyclopentane and n-heptane in a weight ratio of 1:1.

[0098] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0099] (1) mixing a low-voltage-driven color-changing nanomaterial and polydecyl methacrylate with a viscosity of 5000 cps in a weight ratio of 1:50, then adding tetrachloroethane to dilute it by 1.5 times, and ultrasonically dispersing it at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 2.5% by weight of the UV-crosslinkable copolymer with a viscosity of 12000 cps, adding tetrahydrofuran to dilute it by 2 times, stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polysiloxane copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0100] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0101] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0102] Example 7

[0103] This embodiment provides a method for preparing a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0104] (1) The sulfiding agent is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the S solution is obtained after cooling, which is set aside; the metal compound is dispersed in a solvent at a weight ratio of 1:8, and nitrogen is passed through the solvent at a heating condition of 120°C for 15 minutes to remove dissolved oxygen, and the M solution is obtained after cooling, which is set aside; in this step, the metal compound is a metal salt, and the metal salt is specifically formed by mixing bismuth chloride and bismuth acetate at a molar ratio of 1:1; the sulfiding agent is p-toluenethiophenol; the molar ratio of the metal element in the metal compound to the sulfur element in the sulfiding agent is 2:10; the S solution and the M solution are both prepared using a mixture obtained by compounding aniline and pyridine at a weight ratio of 1:1 as a solvent;

[0105] (2) heating the S solution to 220° C., and then dripping the S solution into the M solution within 30 minutes. After the dripping is completed, the timing is started, and the heat preservation reaction is carried out. A surfactant is added in the middle of the reaction. When the heat preservation reaction time reaches 5 hours from the start of the timing, the temperature is lowered and the reaction is terminated to obtain a reaction solution. In this step, the surfactant is added at 90 minutes from the start of the timing after the dripping is completed. The surfactant is cyclohexanethiol, and the molar ratio between the surfactant and the metal element in the metal compound is 30:1.

[0106] (3) The reaction solution was bottled and placed in an ultrasonic tank, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged at speeds of 100 r / min, 3000 r / min, and 5000 r / min (30 min each time), and the solid obtained between the centrifugal speeds of 3000-5000 r / min was taken as the residue; 100 times the weight of an alkane solvent was added to the residue, stirred at a speed of 300 r / min and ultrasonically dispersed at a frequency of 30 kHz for 1 h, and then centrifuged twice at a speed of 5000 r / min (30 min each time), and then washed and dried to obtain a low-voltage-driven color-changing nanomaterial; in this step, the alkane solvent was isooctane.

[0107] This embodiment also provides an application method of a low-voltage driven color-changing nanomaterial, comprising the following steps:

[0108] (1) mixing a low-voltage-driven color-changing nanomaterial and polydecyl methacrylate with a viscosity of 4500 cps in a weight ratio of 1:50, then adding tetrachloroethane to dilute the mixture by 1.5 times, and ultrasonically dispersing the mixture at a frequency of 30 kHz for 1 hour, and then spinning the tetrachloroethane to obtain a first emulsion; adding a photocuring initiator equivalent to 2.5% by weight of the UV-crosslinkable copolymer with a viscosity of 8000 cps, adding tetrahydrofuran to dilute the mixture by 2 times, stirring, and then spinning the tetrahydrofuran to obtain a second emulsion; in this step, the UV-crosslinkable copolymer is a polyacrylate-polystyrene copolymer; and the photocuring initiator is trimethylbenzoyldiphenylphosphine oxide;

[0109] (2) blending the first emulsion and the second emulsion in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0110] (3) According to the coating thickness of 50 μm, the coating slurry was coated between two 50 μm thick ITO conductive film layers, and cross-linked and cured under ultraviolet light for 3 minutes to obtain an electrically polarized color-changing optical film.

[0111] Example 8

[0112] The difference between this embodiment and embodiment 7 is that the metal salt is specifically formed by mixing bismuth chloride, bismuth acetate and antimony chloride in a molar ratio of 1:1:0.2.

[0113] Example 9

[0114] The difference between this embodiment and embodiment 1 is that, in step (2) of preparing the low-voltage driven color-changing nanomaterial, the timing of adding the surfactant is adjusted to 30 minutes before the temperature drops to terminate the reaction.

[0115] Example 10

[0116] The difference between this embodiment and embodiment 9 is that the surfactant is adjusted to Triton X-100.

[0117] Comparative Example

[0118] Comparative Example 1

[0119] This comparative example provides a method for preparing electrically polarized particles and an application thereof in electrically polarized color-changing optical films.

[0120] First, prepare titanium dioxide nanotubes:

[0121] 20g of nano-titanium dioxide and 40g of hexadecyltrimethylammonium bromide were mixed in a mass ratio, then added to 600mL of 10mol / L sodium hydroxide aqueous solution, mixed evenly, placed in a hydrothermal kettle and subjected to hydrothermal reaction at 150°C for 24h. After the reaction was completed, the product was filtered out, and then the product was soaked in 1mol / L nitric acid solution for 2h. After soaking, it was filtered, the product was washed to neutrality, and dried. The dried product was calcined at 500°C for 2h to obtain titanium dioxide nanotubes.

[0122] The preparation method of the electrically polarized particles is as follows:

[0123] (1) 10 g of titanium dioxide nanotubes were dispersed in 200 mL of 1.0 mol / L sodium iodide solution, and the dispersion was placed in a closed container. The closed container was evacuated to a pressure of 0.1 to 1 Pa, followed by magnetic stirring and adsorption for 3 h. After adsorption, the mixture was filtered, washed with water 7 times, and dried to obtain titanium dioxide nanotubes loaded with iodine salt;

[0124] (2) 8 g of iodine-loaded titanium dioxide nanotubes were added to 100 mL of toluene to obtain a dispersion, and 40 g of 3-aminopropane triethoxysilane was added to the dispersion. The dispersion was then heated to 70° C. under a nitrogen atmosphere for 24 h. After the reaction was completed, the dispersion was filtered and washed to obtain amino-modified titanium dioxide nanotubes.

[0125] (3) 8 g of amino-modified titanium dioxide nanotubes were dispersed in 340 mL of deionized water, then stirred and heated to 50°C. Chlorine gas was introduced into the reaction solution at a rate of 8 mL / min for 2 h of oxidation reaction. After the reaction was completed, the solution was filtered and washed to obtain iodine-containing titanium dioxide nanotubes.

[0126] (4) 39.0 g of 2-methyl-4,6-bis(3,5-dicarboxyphenyl)amino-1,3,5-triazine and 15.4 g of N,N-carbonyldiimidazole were added to 400 mL of dichloromethane, and then heated to 65 ° C for 6 h. After the reaction, it was naturally cooled to room temperature. The product was placed in an ice bath, and then 7.8 g of iodine-containing titanium dioxide nanotubes were added and stirred for 4 h. After the reaction, it was filtered and the filter cake was washed with dichloromethane 5 times and then dried to obtain polarized particles.

[0127] The application of electrochromic optical film includes the following steps:

[0128] (1) The electrically polarized particles and polyoctyl methacrylate (viscosity 4570 cps) were mixed in a weight ratio of 1:25, and then dichloromethane was added to dilute the mixture 1.5 times. After ultrasonic mixing, the solvent dichloromethane was spin-dried to obtain emulsion A;

[0129] (2) adding 0.8% by weight of 2,4,6-trimethylbenzoyldiphenylphosphine oxide to a polyacrylate polystyrene copolymer (viscosity of 12000 cps), then adding acetone to dilute the mixture by 2 times, stirring the mixture evenly, and then spinning off the acetone solvent to obtain emulsion B;

[0130] (3) blending emulsion A and emulsion B in a volume ratio of 1:8, and obtaining a coating slurry after stirring and vacuum degassing;

[0131] (4) The coating slurry was coated between two ITO conductive films with a thickness of 50 μm, and then placed under a UV lamp for light cross-linking and curing for 3 minutes to obtain an electrochromic optical film.

[0132] Comparative Example 2

[0133] The difference between this embodiment and embodiment 1 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the order of adding materials is changed, and the S solution is added to the M solution.

[0134] Comparative Example 3

[0135] The difference between this embodiment and embodiment 2 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the order of adding materials is changed, and the M solution is added to the S solution.

[0136] Comparative Example 4

[0137] The difference between this embodiment and embodiment 1 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the timing of adding the surfactant is adjusted to 3 minutes before the temperature drops to complete the reaction.

[0138] Comparative Example 5

[0139] The difference between this embodiment and embodiment 10 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the timing of adding the surfactant is adjusted to 5 minutes before the temperature drops to complete the reaction.

[0140] Comparative Example 6

[0141] The difference between this embodiment and embodiment 6 is that, in step (2) of preparing the low-voltage driven color-changing nanomaterial, the timing of adding the surfactant is adjusted to 105 minutes after the start of the reaction.

[0142] Comparative Example 7

[0143] The difference between this comparative example and Example 1 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the S solution is heated to 130° C. and then the temperature is no longer increased.

[0144] Comparative Example 8

[0145] The difference between this comparative example and Example 1 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the S solution is heated to 230° C. and then the temperature is no longer increased.

[0146] Comparative Example 9

[0147] The difference between this comparative example and Example 1 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the temperature is lowered and the reaction is terminated when the heat preservation reaction time reaches 0.5 h from the start of the timing.

[0148] Comparative Example 10

[0149] The difference between this comparative example and Example 1 is that in step (2) of preparing the low-voltage driven color-changing nanomaterial, the temperature is lowered and the reaction is terminated when the heat preservation reaction time reaches 6 hours from the start of the timing.

[0150] Comparative Example 11

[0151] The difference between this comparative example and Example 1 is that when preparing the S solution and the M solution, both were prepared according to the standard of solute weight: solvent weight = 1:1.

[0152] Comparative Example 12

[0153] The difference between this comparative example and Example 1 is that, when preparing the S solution and the M solution, both were prepared according to the standard of solute weight:solvent weight=1:15.

[0154] Comparative Example 13

[0155] The difference between this comparative example and Example 1 is that the molar ratio of the metal element in the metal compound to the sulfur element in the vulcanizing agent is 1:1.

[0156] Comparative Example 14

[0157] The difference between this comparative example and Example 1 is that the molar ratio of the metal element in the metal compound to the sulfur element in the vulcanizing agent is 2:11.

[0158] Performance testing methods

[0159] 1. Response time and transmittance adjustment range

[0160] The test was performed using the TH-100 haze meter provided by Hangzhou Caipu Technology Co., Ltd. and the STG-500W AC voltage-regulated power supply provided by Zhejiang Chengqiang Electric Co., Ltd. The test steps are as follows:

[0161] (1) First test the initial value of the visible light transmittance of the film under 0V conditions.

[0162] (2) Adjust the voltage to 110V / 220V and start timing at the same time; record the maximum visible light transmittance of the film and the arrival time (manual timing, rounding).

[0163] (3) Turn off the power and start timing at the same time, recording the time when the visible light transmittance of the film is ≤ (initial value + 2%) (manual timing, rounding).

[0164] Under human eye observation, the visible light transmittance must be greater than 2% to see obvious changes. Therefore, in the above method, the node where the dark state response ends is set to the initial value + 2%.

[0165] The time it takes for the visible light transmittance to change from the initial value to the maximum value is recorded as the bright state response time, the time it takes for the visible light transmittance to change from the maximum value to the initial value + 2% is recorded as the dark state response time, and the range between the maximum visible light transmittance and the initial value is recorded as the transmittance adjustment range. The test results of the bright state response time, dark state response time, and transmittance adjustment range are shown in Table 1.

[0166] 2. Color difference (Lab value)

[0167] The Lab value of the electrochromic optical film in the dark state was measured using a CS-700 haze meter provided by Hangzhou Caipu Technology Co., Ltd. The results are shown in Table 1.

[0168] 3. SEM images

[0169] Reference Figure 1-Figure 4 It can be seen that the low-voltage driven color-changing nanomaterial prepared in this application has a certain aspect ratio and a certain surface roughness, resulting in a unique microscopic morphology.

[0170]

[0171]

[0172] Combining Examples 1-8 with Comparative Example 1 and Table 1, it can be seen that the light-state response times measured for Examples 1-9 are mostly 1s, with a small portion being 2s, while the dark-state response times are all within 10s. In contrast, the light-state response time for Comparative Example 1 is 2s, while the dark-state response time is as long as 7s, indicating that the electrically polarized chromic optical films of Examples 1-8 have faster response speeds. The results of the transmittance adjustment range show that the electrically polarized chromic optical films of Examples 1-8 have a large transmittance adjustment range, whether under high voltage conditions of 220V or low voltage conditions of 110V. The color difference (Lab value) test results also show that the colors displayed by Examples 1-8 are not limited to a specific color, but can be combined based on red and green, and the brightness and darkness can be adjusted by black. After mixing with molybdenum blue, a wide color adjustment range can be achieved within the RGB color space.

[0173] Combining Examples 1-3, Examples 9-10, Comparative Example 1 and Table 1, it can be seen that the dark response time measured in Example 9 is between Example 1 and Comparative Example 1, indicating that when the total insulation reaction time of the S solution and the M solution is 1 hour, and the surfactant includes a thiol compound, the timing of adding the surfactant should not be too early, and it is best to add 10-15 minutes before the reaction is completed by cooling. This is because premature addition of thiol will react with the metal compound, while non-thiol surfactants do not have this limitation.

[0174] Combining Examples 1-2, Comparative Example 1 and Comparative Examples 2-3 and Table 1, it can be seen that the response time of Comparative Example 2 is greatly extended compared with Example 1, and the transmittance adjustment range is also significantly reduced. Comparative Example 3 cannot even measure meaningful data, indicating that the addition sequence specified in this application is a necessary condition for the successful preparation of low-voltage driven color-changing nanomaterials.

[0175] Combining Examples 1-8 and Comparative Examples 4-6 with Table 1, it can be seen that the response time of Comparative Examples 4-6 is longer and the transmittance adjustment range is smaller, indicating that the surfactant should be added at least 10 minutes before the temperature drops to the end of the reaction, and should not be later than 90 minutes after the reaction starts. Figure 5 Taking Comparative Example 5 as an example, since the surfactant was added too late, the nanomaterials agglomerated, thereby affecting the performance of the electrochromic optical film.

[0176] Combining Example 1 and Comparative Examples 7-8 with Table 1, it can be seen that data is missing in Comparative Examples 7-8, and the data that can be measured is also significantly poor. This is because the reaction temperature of 130°C is too low to allow the metal compound and the vulcanizing agent to fully react; and the reaction temperature of 230°C is too high, resulting in product agglomeration, which in turn affects the performance of the low-voltage-driven color-changing nanomaterials and the electrically polarized color-changing optical film. The appropriate temperature should be limited to between 140-220°C.

[0177] Combining Example 1 and Comparative Examples 9-10 and Table 1, it can be seen that Comparative Example 9 cannot measure effective data, and although Comparative Example 10 measures data, the dark state response time is extremely long and the transmittance adjustment range is significantly smaller. This is because the time of Comparative Example 9 is not enough for the metal compound and the vulcanizing agent to fully react, and the time of Comparative Example 10 is too long, resulting in agglomeration of the product, indicating that the appropriate reaction time should be limited to the range of 1-5h. Figure 6 Taking Comparative Example 9 as an example, due to insufficient reaction time, the reaction between the S solution and the M solution was incomplete, and the nanomaterial had already decomposed during the SEM test, leaving traces.

[0178] Combining Example 1 and Comparative Examples 11-14 with Table 1, it can be seen that Example 11 cannot measure a representative dark response time, while the dark response times measured in Examples 12-14 are all longer, and Comparative Examples 11, 12, and 14 show a smaller transmittance adjustment range, indicating that when preparing the S solution and the M solution, the solute should be dispersed in the first solvent at a weight ratio of 1: (2-10), and the metal element in the metal compound and the sulfur element in the sulfiding agent should maintain a molar ratio of 2: (3.5-10).

[0179] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing a low-voltage driven color-changing nanomaterial, characterized in that: The following steps are involved: (1) Using an amine compound as a solvent, preparing an M solution containing a metal salt as a solute and an S solution containing a sulfiding agent as a solute, and setting them aside; the metal element contained in the metal salt includes at least one of cerium, samarium, indium, manganese, copper, antimony, zirconium, bismuth, rhenium, tungsten, cobalt, and molybdenum; the sulfiding agent is sulfur or an organic sulfur compound; the organic sulfur compound is at least one of thiophenol, thioether, and thiol; the molar ratio of sulfur in the S solution to the metal element in the M solution is (3.5-10):2; (2) Heat one of the S solution and the M solution to 140-220°C, then add the other solution, start timing and keep the temperature for reaction, add a surfactant within 0.5-1.5 hours after the start of the reaction, cool down and end the reaction after the reaction time reaches 1-5 hours, and obtain a reaction solution, wherein the surfactant is added at least 10 minutes before the end of the reaction by cooling down; the order of adding the S solution and the M solution is: when the sulfiding agent is an organic sulfur compound, add the S solution to the M solution; when the sulfiding agent is elemental sulfur, add the M solution to the S solution; The solution is added to the S solution; the surfactant is at least one of Triton X-100, oleic acid, Span, Tween, ethanedithiol, 1,3-propanedithiol, 1-hexanethiol, 1,6-hexanedithiol, cyclohexanethiol, and n-dodecyl mercaptan, and the molar ratio between the surfactant and the metal element in the metal compound is (5-30):1; when the total insulation reaction time of the S solution and the M solution is 1 hour, and the surfactant includes a thiol compound, the surfactant is added 10-30 minutes before the reaction is cooled and the reaction is completed; (3) The reaction liquid is ultrasonically dispersed, and then the amine compounds in the reaction liquid are removed by centrifugation. The solid residue is added to an alkane solvent for dispersion, and then the alkane solvent is removed by centrifugation to obtain a new solid residue. The new solid residue is washed to obtain a low-voltage driven color-changing nanomaterial.

2. The method for preparing a low-voltage driven color-changing nanomaterial according to claim 1, characterized in that: The amine compound is at least one of aniline, diphenylamine, dodecylamine, cyclohexylamine, oleylamine, pyridine and o-phenylenediamine.

3. The method for preparing a low-voltage driven color-changing nanomaterial according to claim 2, characterized in that: The organic sulfur compound is at least one of p-toluenethiophenol, methyl allyl trisulfide, thiourea, guanylthiourea, allylthiourea, and 1,3-diethylthiourea.

4. The method for preparing a low-voltage driven color-changing nanomaterial according to claim 2, characterized in that: The metal salt includes at least one of chloride, bromide, iodide, and organic acid salt.

5. The method for preparing a low-voltage driven color-changing nanomaterial according to claim 4, characterized in that: The metal salt includes an organic acid salt, and the organic acid salt includes at least one of indium acetate, samarium acetate, manganese acetate, manganese oxalate, molybdenum neodecanoate, copper isooctanoate, tungsten oxalate, cobalt oleate, and zirconium isooctanoate.

6. The method for preparing a low-voltage driven color-changing nanomaterial according to claim 5, characterized in that: The metal salt contains metal elements including antimony.

7. The method for preparing a low-voltage driven color-changing nanomaterial according to claim 6, characterized in that: The metal elements contained in the metal salt are bismuth and antimony, and the molar ratio between the bismuth element and the antimony element in the metal salt is 10:

1.

8. A method for applying the low-voltage driven color-changing nanomaterial prepared by the method for preparing the low-voltage driven color-changing nanomaterial according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) A low-voltage-driven color-changing nanomaterial prepared by the method for preparing a low-voltage-driven color-changing nanomaterial according to any one of claims 1 to 7 and polymethacrylate with a viscosity of 3000-5000 cps are mixed in a weight ratio of 1:(2-50), an organic solvent is added to the mixture and ultrasonically dispersed, and the organic solvent is spin-dried to obtain a first emulsion; a photocuring initiator and an organic solvent are added to a UV-crosslinkable copolymer with a viscosity of 7000-12000 cps, the organic solvent is stirred and spin-dried to obtain a second emulsion; the UV-crosslinkable copolymer is one of a polyacrylate-polystyrene copolymer and a polyacrylate-polysiloxane copolymer; the weight of the photocuring initiator is equivalent to 0.1-3% of the weight of the UV-crosslinkable copolymer; (2) blending the first emulsion and the second emulsion, stirring and vacuum degassing to obtain a coating slurry; (3) The coating slurry is coated between two ITO conductive film layers and cross-linked and cured under ultraviolet light to obtain an electrochromic optical film.

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