Colorless and transparent photochromic driver, preparation method and application of colorless and transparent photochromic driver to intelligent curtain

Abstract

The invention relates to the technical field of drivers, in particular to a colorless and transparent photochromic driver, a preparation method and application of the colorless and transparent photochromic driver to an intelligent curtain. The colorless transparent photochromic driver comprises a first flexible optical transparent layer, a second flexible optical transparent layer and a photochromic layer clamped between the first flexible optical transparent layer and the second flexible optical transparent layer; the thermal expansion coefficients of the first flexible optical transparent layer and the second flexible optical transparent layer are different. When illumination or temperature changes, macroscopic deformation can be generated based on the difference of thermal expansion coefficients of the two flexible optical transparent layers, meanwhile, the photochromic layer is colorless initially, but spectrum adjustment can be achieved when the photochromic layer is changed from colorless to colored (such as blue) under sunlight irradiation. After the photochromic layer changes color, the photothermal conversion efficiency is obviously improved, and the local temperature can be quickly increased, so that the deformation of the driver is promoted and amplified, and the synergistic interaction of driving and dimming functions is realized.

Description

Technical Field

[0001] This invention relates to the field of software driver technology, and in particular to a colorless transparent photochromic driver, its preparation method, and its application in intelligent curtains. Background Technology

[0002] Soft actuators, as an emerging environmentally responsive device, are typically composed of flexible polymer or composite materials. Their core function is to convert received physical or chemical stimuli (such as electric fields, light, temperature, magnetic fields, and humidity) into controllable macroscopic mechanical deformation or motion. Over the past two decades, with the rapid development of cutting-edge fields such as soft robotics, wearable devices, and tunable optics, actuator technology is undergoing a profound evolution from traditional rigid motor-linkage combinations to "thin-film, distributed, silent operation, and bearingless structures." However, existing commercially available soft actuator materials, such as shape memory alloys (SMA) and liquid crystal elastomers (LCE), often exhibit colored or semi-transparent states due to their inherent physical properties. This optical limitation significantly restricts their application in scenarios requiring high transparency.

[0003] Against this technological backdrop, applying the environmental response characteristics of soft actuators to the field of building energy conservation, particularly in the development of intelligent curtains, has become a research direction of great interest. Statistics show that approximately 40% of global building energy consumption originates from heat exchange through windows. Therefore, efficiently controlling the light transmission and heat insulation performance of windows is crucial for achieving building energy conservation and emission reduction. Intelligent curtains are a special application of soft actuators. Their working principle utilizes the actuator's autonomous response to parameters such as external ambient temperature and light intensity, causing preset deformation or color changes. This dynamically adjusts the amount of light and heat entering the room by covering the window, ultimately achieving the goals of stabilizing room temperature, reducing air conditioning load, and decreasing energy consumption.

[0004] Although the concept of smart curtains has been around for many years, mainstream products on the market still face numerous technological bottlenecks. Currently, common smart curtain solutions mainly include motor-driven roller blinds / venetian blinds, LCD dimming glass, and electrochromic glass. While these solutions achieve intelligent control to some extent, they also have drawbacks such as mechanical noise, reduced lighting, and increased energy consumption.

[0005] Therefore, existing technologies need to be improved. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a colorless transparent photochromic actuator, a preparation method thereof, and its application in intelligent curtains, in order to solve the problems of mechanical noise, reduced light transmission, and increased energy consumption of existing actuators.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a colorless transparent photochromic actuator, comprising a first flexible optically transparent layer, a second flexible optically transparent layer, and a photochromic layer sandwiched between the two; The first flexible optical transparent layer and the second flexible optical transparent layer have different coefficients of thermal expansion.

[0008] Optionally, the coefficients of thermal expansion of the second flexible optical transparent layer and the first flexible optical transparent layer differ by 17-18 times.

[0009] Specifically, the coefficient of thermal expansion of the first flexible optically transparent layer is 7.847 × 10⁻⁶. -4 The coefficient of thermal expansion of the second flexible optically transparent layer is 4.41 × 10⁻⁶ °C. -5 / ℃, a difference of 17.8 times.

[0010] Preferably, the second flexible optically transparent layer is a colorless transparent polyimide film; the first flexible optically transparent layer is a colorless transparent polyethylene film, a colorless transparent polypropylene film, or a colorless transparent polyester film.

[0011] Preferably, the thickness of the second flexible optically transparent layer is less than the thickness of the first flexible optically transparent layer.

[0012] Preferably, the thickness of the second flexible optically transparent layer is 15-80 μm, and the thickness of the first flexible optically transparent layer is 30-100 μm.

[0013] Optionally, the functional material of the photochromic layer is an ultrafine tungsten oxide nanowire, the ultrafine tungsten oxide nanowire having a diameter of 1-3 nm and a length of 10-100 μm; Optionally, the thickness of the photochromic layer is 1.0-1.25 μm.

[0014] Secondly, the present invention provides a method for preparing a colorless and transparent photochromic actuator, comprising the following steps: A second flexible optically transparent layer is fabricated on the substrate; The second flexible optically transparent layer is peeled off from the substrate, and a photochromic layer is prepared on the obtained second flexible optically transparent layer; The colorless transparent photochromic actuator is obtained by combining the first flexible optical transparent layer with the second flexible optical transparent layer with a photochromic layer.

[0015] Optionally, the substrate is preferably a quartz glass substrate.

[0016] Optionally, the preparation of a second flexible optically transparent layer on a substrate includes the following steps: dropping a precursor of a functional material containing the second flexible optically transparent layer (preferably polyamic acid) onto the substrate and heating it to obtain the second flexible optically transparent layer (colorless transparent polyimide film).

[0017] Optionally, a photochromic layer is prepared on the obtained second flexible optically transparent layer, comprising the following steps: preparing a functional substance dispersion containing a photochromic layer; spraying the functional substance dispersion containing a photochromic layer onto the second flexible optically transparent layer to obtain the photochromic layer.

[0018] Optionally, the second flexible optically transparent layer can be bombarded with plasma before spraying.

[0019] The aim is to enhance the adhesion of photochromic layers (such as ultrafine tungsten oxide nanowires).

[0020] Thirdly, the present invention provides an application of a colorless transparent photochromic actuator in intelligent curtains.

[0021] Fourthly, the present invention provides an intelligent curtain, including a glass substrate and a colorless transparent photochromic actuator disposed on the glass substrate.

[0022] Fifthly, the present invention provides a method for preparing an intelligent curtain, comprising the following steps: winding and fixing the colorless transparent photochromic actuator onto a column and placing it in an oven for thermoforming. Take a glass substrate and fix the thermoplasticized colorless transparent photochromic actuator onto the glass substrate to obtain the intelligent curtain.

[0023] Optionally, the temperature in the oven is set to 70-90°C.

[0024] Beneficial Effects: This invention provides a colorless and transparent photochromic actuator, its preparation method, and its application in intelligent curtains. The second flexible optically transparent layer, the first flexible optically transparent layer, and the photochromic layer of the colorless and transparent photochromic actuator of this invention are initially colorless and transparent. When exposed to light or temperature changes, macroscopic deformation occurs due to the difference in the thermal expansion coefficients of the second and first flexible optically transparent layers. Simultaneously, the photochromic layer, initially colorless, changes from colorless to colored (e.g., blue) under sunlight, achieving spectral modulation. Crucially, the photothermal conversion efficiency is significantly improved after the photochromic layer changes color, rapidly increasing the local temperature, thereby promoting and amplifying the actuator's deformation and achieving synergistic effects between driving and dimming functions. The actuator of this invention relies solely on photothermal actuation, achieving passive and silent operation, and does not affect lighting or field of vision when not in use. Furthermore, the preparation process of this invention is simple and low-cost, making it an ideal alternative to intelligent curtains. Through dynamic intelligent control of sunlight, it effectively regulates room temperature, achieving energy conservation and emission reduction. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of the colorless transparent photochromic actuator in Example 1.

[0027] Figure 2 The graph shows the coefficient of thermal expansion of colorless transparent polyethylene tape and colorless transparent polyimide as a function of temperature.

[0028] Figure 3 This is a schematic diagram of the process for preparing a colorless transparent photochromic actuator in Example 1.

[0029] Figure 4 This is a SEM image of the cross-section of the colorless transparent photochromic actuator of Example 1.

[0030] Figure 5 This is a SEM image of the front side of the colorless transparent photochromic driver of Example 1.

[0031] Figure 6 This is a TEM image of the ultrafine tungsten oxide nanowires in Example 1.

[0032] Figure 7 This is an XRD pattern of the ultrafine tungsten oxide nanowires in Example 1.

[0033] Figure 8 The images show the colorless transparent photochromic driver before and after photochromic changes in Example 1.

[0034] Figure 9 Schematic diagram of colorless and transparent polyimide films prepared with different amounts of precursors.

[0035] Figure 10 Thickness diagram of colorless transparent polyimide films prepared with different amounts of precursor.

[0036] Figure 11 A schematic diagram showing the transmittance of colorless and transparent polyimide films prepared with different amounts of precursors.

[0037] Figure 12 A schematic diagram illustrating the driving performance of a transparent photochromic actuator made from colorless and transparent polyethylene tapes of different thicknesses.

[0038] Figure 13 A schematic diagram of a transparent photochromic actuator made from colorless and transparent polyethylene tapes of different thicknesses.

[0039] Figure 14 This is a schematic diagram showing the transmittance of colorless transparent polyethylene tapes of different thicknesses disclosed in the embodiments of this application.

[0040] Figure 15 Schematic diagram of the transmittance of the actuators before and after photochromism for different amounts of ultrafine tungsten oxide nanowires.

[0041] Figure 16 This is a schematic diagram showing the transmittance of the driver of Example 1 before and after photochromism when irradiated with different light sources.

[0042] Figure 17 The diagram shows the coverage changes of the driver in Example 1 after being illuminated by different light sources.

[0043] Figure 18 This is a photograph of the outdoor test of the intelligent curtain in Example 1.

[0044] Figure 19 Comparison of chamber and blackbody temperatures for a colorless, transparent photochromic actuator. Detailed Implementation

[0045] This invention provides a colorless, transparent photochromic actuator, its preparation method, and its application in intelligent curtains. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] like Figure 1As shown, this embodiment provides a colorless transparent photochromic driver 100, including a first flexible optical transparent layer 101, a second flexible optical transparent layer 103 and a photochromic layer 102 sandwiched between the two; The first flexible optical transparent layer 101 and the second flexible optical transparent layer 103 have different coefficients of thermal expansion.

[0047] It should be noted that the second flexible optically transparent layer, the first flexible optically transparent layer, and the photochromic layer of the colorless transparent photochromic actuator in this embodiment are initially colorless and transparent. When exposed to light or temperature changes, macroscopic deformation occurs due to the difference in the thermal expansion coefficients of the second and first flexible optically transparent layers. Simultaneously, the photochromic layer, initially colorless, changes from colorless to colored (e.g., blue) under sunlight, achieving spectral modulation. Crucially, the photothermal conversion efficiency is significantly enhanced after the photochromic layer changes color, rapidly increasing the local temperature, thereby promoting and amplifying the actuator's deformation and achieving synergistic effects between driving and dimming functions. The actuator of this invention relies solely on photothermal actuation, achieving passive, silent operation, and does not affect lighting or field of vision when not in operation. The actuator of this embodiment possesses excellent driving performance and spectral modulation performance, rapidly responding to changes in ambient temperature and outdoor light, replacing traditional blackout curtains in buildings, and achieving room temperature regulation and energy conservation and emission reduction through dynamic control of sunlight.

[0048] In some embodiments, the coefficients of thermal expansion of the second flexible optically transparent layer and the first flexible optically transparent layer differ by a factor of 17-18. The first flexible optically transparent layer has a larger coefficient of thermal expansion than the second, resulting in greater deformation when heated, while the second flexible optically transparent layer, due to its lower coefficient of thermal expansion, exhibits less deformation when heated. This difference in deformation caused by the difference in their coefficients of thermal expansion leads to bending from the side with greater deformation to the side with less deformation. If the difference in their coefficients of thermal expansion is too small, the actuator's driving effect will be weak; if the difference is too large, the interface between the two flexible optically transparent layers will be poor, easily damaging the actuator.

[0049] In a preferred embodiment, the coefficient of thermal expansion of the first flexible optically transparent layer is 7.847 × 10⁻⁶. -4 The coefficient of thermal expansion of the second flexible optically transparent layer is 4.41 × 10⁻⁶ °C. -5 / ℃, a difference of 17.8 times.

[0050] In one embodiment, the second flexible optically transparent layer is a colorless transparent polyimide film; The first flexible optically transparent layer is made of colorless transparent polyethylene, colorless transparent polypropylene, or colorless transparent polyester (preferably colorless transparent polyethylene). In this embodiment, the selection of the first flexible optically transparent layer 101 requires it to have a large coefficient of thermal expansion. Other aspects of the first flexible optically transparent layer are not specifically limited; those skilled in the art can select according to actual needs. Preferably, the material of the first flexible optically transparent layer 101 includes one or more of colorless transparent polyethylene (PE tape), polypropylene (PP tape), and polyester (PET tape), preferably PET tape, more preferably PP tape, and most preferably PE tape. Furthermore, this invention does not particularly limit the source of the material for the first flexible optically transparent layer; it can be prepared using methods well known to those skilled in the art or purchased from the market.

[0051] like Figure 2 The figure shows the change in the coefficient of thermal expansion of the colorless transparent polyethylene and polyimide films with temperature in this embodiment. The thickness of the colorless transparent polyethylene film is 50 μm, and the thickness of the polyimide film is 30 μm.

[0052] In some embodiments, the thickness of the second flexible optically transparent layer is less than the thickness of the first flexible optically transparent layer. The first flexible optically transparent layer is an active layer and undergoes significant deformation, while the second flexible optically transparent layer is a passive layer and does not deform significantly. Making the thickness of the first flexible optically transparent layer greater than that of the second flexible optically transparent layer can improve the driving effect of the actuator.

[0053] In one embodiment, the thickness of the second flexible optically transparent layer is 15-80 μm, preferably 50 μm; the thickness of the first flexible optically transparent layer is 30-100 μm, preferably 30 μm, 50 μm, or 100 μm.

[0054] It should be noted that the thickness of the second flexible optical transparent layer is specifically controlled by the amount of precursor material containing the second flexible optical transparent layer (such as PAA). On a 4cm*4cm substrate glass, the amount ranges from 0.3 to 1.5mL.

[0055] In one embodiment, the functional material of the photochromic layer is ultrafine tungsten oxide nanowires, the ultrafine tungsten oxide nanowires having a diameter of 1-3 nm and a length of 10-100 μm.

[0056] It should be noted that the functional material, ultrafine tungsten oxide nanowires, in this embodiment is initially colorless and transparent, turning blue when exposed to light or temperature changes. Under light, it significantly enhances photothermal conversion efficiency, rapidly increasing local temperature, thereby promoting and amplifying the deformation of the actuator, achieving synergistic effects between actuation and dimming functions. This functional material is the truly core component of the photochromic layer.

[0057] In some embodiments, the thickness of the photochromic layer is 1.0-1.25 μm. This thickness corresponds to a 10 mL solution volume of ultrafine tungsten oxide nanowires. Figure 15 As shown, this allows the photochromic layer to be used in a smaller amount while ensuring high transmittance adjustment.

[0058] This embodiment also provides a method for preparing a colorless, transparent photochromic actuator, such as... Figure 3 As shown, it includes the following steps: A second flexible optically transparent layer (colorless transparent polyimide) is prepared on a substrate (such as quartz glass). The second flexible optically transparent layer was peeled off from the substrate, and a photochromic layer (ultrafine tungsten oxide nanowires) was prepared on the obtained second flexible optically transparent layer. The colorless transparent photochromic actuator is obtained by combining a first flexible optically transparent layer (colorless transparent polyethylene, i.e., PE tape) with a second flexible optically transparent layer having a photochromic layer.

[0059] The preparation process of this invention is simple and low in cost.

[0060] In one embodiment, the substrate is preferably a quartz glass substrate.

[0061] In some embodiments, the preparation of a second flexible optically transparent layer on a substrate includes the following steps: dropping a precursor of a functional material containing the second flexible optically transparent layer (preferably polyamic acid) onto the substrate and heating it to obtain the second flexible optically transparent layer (colorless transparent polyimide film).

[0062] It should be noted that the heating includes preheating and secondary heating in a vacuum oven. Preheating involves heating at 45℃ and 65℃ for 2 hours respectively. Secondary heating involves heating on a heating table at 100℃, 150℃, and 200℃ for 10 minutes each, and at 250℃ and 300℃ for 30 minutes each. The purpose of preheating is to achieve initial solvent evaporation and pre-curing, while the purpose of secondary heating is to further remove the solvent and cure the material. After coating the surface of the second flexible optically transparent layer and drying, a uniform photochromic film is formed. The photochromic substance undergoes a reversible color change under ultraviolet light while maintaining good optical transparency and mechanical flexibility.

[0063] In some embodiments, the photochromic layer is prepared on the obtained second flexible optically transparent layer, comprising the following steps: preparing a functional substance dispersion containing the photochromic layer; spraying the functional substance dispersion containing the photochromic layer onto the second flexible optically transparent layer to obtain the photochromic layer.

[0064] In some embodiments, the second flexible optically transparent layer is bombarded with plasma before spraying.

[0065] The purpose of this implementation is to enhance the adhesion of photochromic layers (such as ultrafine tungsten oxide nanowires).

[0066] This embodiment also provides an application of a colorless transparent photochromic driver in intelligent curtains.

[0067] This embodiment also provides an intelligent curtain, including a glass substrate and a colorless transparent photochromic driver disposed on the glass substrate.

[0068] In this embodiment, the actuator is curled up and laid out on the glass substrate. As the outside temperature rises, and sunlight causes the actuator to turn blue, it absorbs even more heat. The increased temperature causes the actuator to straighten out and cover the window surface, forming a light-blocking curtain.

[0069] The intelligent curtain in this embodiment is an ideal intelligent curtain that can effectively regulate room temperature through dynamic intelligent control of sunlight, thereby achieving the purpose of energy conservation and emission reduction.

[0070] This embodiment also provides a method for preparing an intelligent curtain, including the following steps: winding and fixing the colorless transparent photochromic driver onto a column and placing it in an oven for thermoforming. Take a glass substrate and fix the thermoplasticized colorless transparent photochromic actuator onto the glass substrate to obtain the intelligent curtain.

[0071] This embodiment can produce a roll-up intelligent curtain.

[0072] In one embodiment, the temperature of the oven is set to 70-90°C (preferably 80°C).

[0073] The present invention will be further described below through specific embodiments.

[0074] Example 1 1. Fabrication of a colorless, transparent photochromic actuator, such as... Figure 3 As shown, it includes the following steps: A second flexible optically transparent layer (colorless transparent polyimide) is prepared on a substrate (such as quartz glass). The second flexible optically transparent layer was peeled off from the substrate, and a photochromic layer (ultrafine tungsten oxide nanowires) was prepared on the obtained second flexible optically transparent layer. The colorless transparent photochromic actuator is obtained by combining a first flexible optically transparent layer (colorless transparent polyethylene, i.e., PE tape) with a second flexible optically transparent layer having a photochromic layer.

[0075] Specifically, the process involves: plasma bombardment treatment of quartz glass to make its surface hydrophilic and facilitate solution diffusion; transferring the quartz glass to a vacuum oven and dropwise adding the precursor polyamic acid (PAA) onto the surface of the quartz glass to ensure it is fully coated; heating under vacuum at 45°C and 65°C for 2 hours respectively to initially remove the solvent and perform preliminary thermal curing; after initial solvent removal and thermal curing, transferring it to a heating stage and heating at 100°C, 150°C, and 200°C for 10 minutes, and at 250°C and 300°C for 30 minutes respectively to further remove the solvent and perform thermal curing; and finally, obtaining a colorless and transparent polyimide film (i.e., the second flexible optically transparent layer) after cooling.

[0076] The ultrafine tungsten oxide nanowire stock solution was synthesized using tungsten hexachloride, anhydrous ethanol, and n-decyl alcohol via a hydrothermal method. Specifically, 0.3 g of tungsten hexachloride (>99.5%) was added to 80 ml of a solution of anhydrous ethanol and n-decyl alcohol in equal proportions. The solution was then magnetically stirred for 15 min to ensure complete dissolution of the tungsten hexachloride. The solution was then transferred to a 100 ml PTFE-lined stainless steel autoclave and reacted at 180°C for 1.5 h to obtain the ultrafine tungsten oxide nanowire stock solution. The tungsten oxide concentration in the stock solution was 0.0017 g / ml, and the diameter of the ultrafine tungsten oxide nanowires ranged from 1-3 nm, with a length ranging from 10-100 μm. Furthermore, this embodiment does not impose any particular limitation on the source of the photochromic layer; it can be prepared using methods well-known to those skilled in the art or purchased commercially.

[0077] The photochromic layer was prepared by a spray coating method: the prepared ultrafine tungsten oxide nanowire stock solution was thoroughly mixed with cyclohexane (volume ratio 1:2) and centrifuged. The first centrifugation was performed at 8000 rpm for 4 minutes; the second centrifugation at 7000 rpm for 4 minutes; and the third centrifugation at 6000 rpm for 4 minutes. The ultrafine tungsten oxide nanowires after the three centrifugations were dispersed in anhydrous ethanol as the spray coating dispersion.

[0078] A colorless, transparent polyimide film was peeled off from quartz glass and bombarded with plasma to make its surface hydrophilic, facilitating the adhesion of ultrafine tungsten oxide nanowires. The colorless, transparent polyimide film was then fixed on a heating stage and sprayed at a temperature of 75°C to obtain a composite layer of the colorless, transparent polyimide film and a photochromic ultrafine tungsten oxide nanowire layer (i.e., the photochromic layer).

[0079] A composite layer of a colorless transparent polyimide film and a photochromic ultrafine tungsten oxide nanowire layer is combined with a colorless transparent polyethylene tape (first flexible optically transparent layer) to obtain the aforementioned colorless transparent photochromic actuator. In this embodiment, the thickness of the colorless transparent polyethylene tape (first flexible optically transparent layer) is 50µm.

[0080] The thickness of the second flexible optically transparent layer 103 is determined by the amount of precursor PAA per unit area. The preferred amount is 0.3-2.0 mL (quartz glass with dimensions of 4cm*4cm), more preferably 0.6-1.5 mL, and most preferably 0.6-0.9 mL. Those skilled in the art can adjust and select the thickness of the second flexible optically transparent layer 103 according to actual production conditions, the performance and quality of the second flexible optically transparent layer 103, and the overall performance and quality requirements of the actuator. Furthermore, this invention does not impose any particular restrictions on the source of the second flexible optically transparent layer 103; it can be prepared using methods well known to those skilled in the art or purchased commercially. In this embodiment, the amount of PAA used is 0.9 mL. Figure 10 As shown, the corresponding thickness is 35µm.

[0081] The thickness of the photochromic layer 102 is determined by the amount of the original solution for spraying ultrafine tungsten oxide nanowires. Based on the quality and transmittance of the colorless and transparent photochromic actuator, the quality of the photochromic layer, and the photochromic performance, the preferred amount of the original solution for ultrafine tungsten oxide nanowires is 5-20 mL, more preferably 10-20 mL, and in this embodiment, the amount is 10 mL / 4cm*4cm.

[0082] like Figure 4-8 As shown, where Figure 4 This is a SEM image of the cross-section of the colorless transparent photochromic actuator of Example 1. Figure 5 This is a SEM image of the front side of the colorless transparent photochromic driver of Example 1. Figure 6 This is a TEM image of the ultrafine tungsten oxide nanowires in Example 1. Figure 7 This is an XRD pattern of the ultrafine tungsten oxide nanowires in Example 1. Figure 8 The images show the colorless transparent photochromic driver before and after photochromic changes in Example 1. Figure 4 The three-layer structure of the driver can be seen. Figure 5-6 The morphology of ultrafine tungsten oxide nanowires can be observed. Figure 7 Prove that tungsten oxide is W 18 O 49 , Figure 8 This indicates that the driver has good color-changing performance while maintaining light transmission.

[0083] 2. Preparation of intelligent curtains: The prepared colorless and transparent photochromic actuator is thermoplasticized to obtain a rolled actuator, which is then fixed onto quartz glass to obtain an intelligent curtain.

[0084] Example 2 The difference between Example 2 and Example 1 is that the amount of colorless and transparent polyimide precursor PAA used in this example is 0.3 mL.

[0085] Example 3 The difference between Example 3 and Example 1 is that the amount of colorless and transparent polyimide precursor PAA used in Example 3 is 0.6 mL.

[0086] Example 4 The difference between Example 4 and Example 1 is that the amount of colorless and transparent polyimide precursor PAA used in Example 4 is 1.2 mL.

[0087] Example 5 The difference between Example 5 and Example 1 is that the amount of colorless and transparent polyimide precursor PAA used in this example is 1.5 mL.

[0088] Examples 1-5 show that the thickness of the prepared colorless and transparent polyimide layer was controlled by adjusting the amount of the colorless and transparent polyimide precursor PAA. Figure 9 Schematic diagrams of colorless and transparent polyimide films prepared with different amounts of PAA precursor. The results show that if the amount of precursor is too small, the colorless and transparent polyimide film has poor integrity, while if the amount of precursor is too large, bubbles appear in the colorless and transparent polyimide film. Figure 10 Thickness diagrams of colorless transparent polyimide films prepared with different amounts of PAA precursor are shown. The transmittance of colorless transparent polyimide films of different thicknesses was characterized using a UV-Vis-NIR spectrophotometer. Figure 11 The results show that the thickness of the colorless transparent polyimide film has no effect on the transmittance performance of the actuator.

[0089] Example 6 The difference between this embodiment and Embodiment 1 is that the thickness of the polyethylene tape in this embodiment is 30 μm.

[0090] Example 7 The difference between this embodiment and Embodiment 1 is that the thickness of the polyethylene tape in this embodiment is 100 μm.

[0091] In Examples 1, 6, and 7, to compare the driving performance by changing the thickness of the colorless transparent polyethylene tape while keeping the thickness of the colorless transparent polyimide film constant during the preparation process, the driving performance was adjusted. Figure 12 Schematic diagrams of the driving performance of transparent photochromic actuators prepared from colorless transparent polyethylene tapes of different thicknesses. The results show that the driving speed and coverage of the actuators increase with increasing polyethylene tape thickness. Specifically, actuators prepared from 50µm and 100µm thick polyethylene tapes can completely cover the quartz glass surface. Figure 13 A schematic diagram of a transparent photochromic actuator fabricated from colorless and transparent polyethylene tapes of varying thicknesses, as shown below. Figure 13 As shown, the transparent photochromic actuator made of 100µm thick polyethylene tape developed wrinkles due to interface issues after the driving process. Figure 14 This is a schematic diagram illustrating the transmittance of colorless transparent polyethylene tapes of different thicknesses disclosed in the embodiments of this application, as shown below. Figure 14 As shown, the thickness of the polyethylene tape has no effect on the transmittance performance of the driver.

[0092] Example 8 The difference between this embodiment and Embodiment 1 is that the volume of the original solution of the ultrafine tungsten oxide nanowires in this embodiment is 5 mL.

[0093] Example 9 The difference between this embodiment and Embodiment 1 is that the volume of the original solution of the ultrafine tungsten oxide nanowires in this embodiment is 20 mL.

[0094] Examples 1, 8, and 9 regulate photochromic properties by fixing the thickness of colorless transparent polyethylene tape and the thickness of colorless transparent polyimide layer, and by changing the amount of the original solution of ultrafine tungsten oxide nanowires. Figure 15 The image shows the transmittance of the actuators prepared with different amounts of ultrafine tungsten oxide nanowires before and after photochromism. The transmittance of the transparent photochromic actuators prepared with different amounts of ultrafine tungsten oxide nanowires was characterized using a UV-Vis-NIR spectrophotometer. The results are as follows: Figure 15 As shown, the transparent photochromic actuators prepared with different amounts of ultrafine tungsten oxide nanowires are basically consistent and maintain high transmittance before photochromism. After photochromism, the transmittance of the actuator in the near-infrared band decreases significantly, and the higher the amount of ultrafine tungsten oxide nanowires, the lower the transmittance in the near-infrared band. At the same time, the actuator maintains high visible light transmittance.

[0095] The colorless, transparent photochromic actuator obtained in Example 1 was subjected to sunlight ( Figure 16 Left), xenon lamp ( Figure 16 Right), ultraviolet lamp ( Figure 16 The driver was irradiated to induce photochromism, and characterized using a UV-Vis-NIR spectrophotometer. The actual outdoor light power density was measured, and both the xenon lamp and the UV lamp were controlled to have the same light power density and the same irradiation time. The results are as follows: Figure 16 As shown, Figure 16 This diagram illustrates the transmittance of the actuator before and after photochromic changes, obtained using different light sources. The results show that the transmittance of the actuator decreases most significantly after ultraviolet light irradiation, while the transmittance decreases least significantly after xenon lamp irradiation.

[0096] The colorless, transparent photochromic actuator obtained in Example 1 was photochromic using an ultraviolet lamp. Near-infrared, ultraviolet, and xenon lamps were used to irradiate the actuator, activating it and testing the change in quartz glass coverage during activation. The results are as follows: Figure 17As shown, the driver irradiated by near-infrared lamps exhibits better driving performance, including the fastest response speed and the largest coverage. The driver irradiated by ultraviolet lamps has the worst driving performance.

[0097] Outdoor testing allows for a direct and intuitive evaluation of the performance of the transparent photochromic driver.

[0098] The intelligent curtain obtained in Example 1 was assembled on a perforated foam box to simulate a house. Figure 18 This is a schematic diagram of the outdoor test results. From left to right, the samples are quartz glass, a smart curtain without a photochromic layer, and a complete smart curtain, respectively. Results were recorded at 8:00 AM, 12:00 PM, and 4:00 PM. The results show that around 8:00 AM, the actuator began to turn blue and gradually covered the glass window; around 12:00 PM, the actuator completely turned blue and covered the entire glass window; around 4:00 PM, the smart curtain returned to its initial state.

[0099] The temperatures of the blackbody and the foam box chamber were recorded using a multi-channel temperature measuring instrument. (See [link to documentation]). Figure 19 The results showed that when the chamber was not equipped with a colorless, transparent, photochromic intelligent curtain, its blackbody temperature reached a maximum of 84.8°C, and its internal temperature reached a maximum of 58.1°C. In contrast, when equipped with a colorless, transparent, photochromic actuator, the blackbody temperature decreased by a maximum of 15.2°C, and the internal temperature decreased by a maximum of 5.7°C. Furthermore, compared to an intelligent curtain without a photochromic layer, a complete intelligent curtain regulated the blackbody temperature by 14.3°C and the internal temperature by 4°C, indicating that the photochromic layer plays a major role in temperature regulation. These results demonstrate that the colorless, transparent, photochromic actuator of this invention can adjust the indoor temperature according to changes in ambient temperature and light intensity, reducing air conditioning energy consumption and creating a comfortable living environment.

[0100] In summary, this invention provides a colorless, transparent photochromic actuator, its preparation method, and its application in intelligent curtains. The photochromic layer is initially colorless, but changes from colorless to colored (e.g., blue) under sunlight, achieving spectral modulation. Crucially, the photothermal conversion efficiency is significantly improved after the photochromic layer changes color, rapidly increasing the local temperature, thereby promoting and amplifying the actuator's deformation and achieving synergistic effects between driving and dimming functions. This invention's actuator relies solely on photothermal actuation, achieving passive, silent operation, and does not affect lighting or visibility when not in use. Furthermore, the invention's preparation process is simple and low-cost, making it an ideal alternative to intelligent curtains. Through dynamic intelligent control of sunlight, it effectively regulates room temperature, achieving energy conservation and emission reduction.

[0101] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A colorless, transparent photochromic driver, characterized in that, comprising a first flexible optical transparent layer, a second flexible optical transparent layer and a photochromic layer sandwiched between the two layers; the first flexible optical transparent layer and the second flexible optical transparent layer have different thermal expansion coefficients.

2. A colorless, transparent photochromic driver according to claim 1, wherein, the thermal expansion coefficient of the second flexible optical transparent layer and the first flexible optical transparent layer differ by 17-18 times.

3. A colourless, transparent photochromic driver according to claim 2, characterised in that, the second flexible optical transparent layer is a colorless transparent polyimide film; the first flexible optical transparent layer is a colorless transparent polyethylene film, a colorless transparent polypropylene film or a colorless transparent polyester film.

4. A colourless, transparent photochromic driver according to claim 3, characterised in that, the thickness of the second flexible optical transparent layer is less than the thickness of the first flexible optical transparent layer, preferably, the thickness of the second flexible optical transparent layer is 15-80 μm, and the thickness of the first flexible optical transparent layer is 30-100 μm.

5. A colorless, transparent photochromic driver according to claim 1, wherein, the functional substance of the photochromic layer is ultrafine tungsten oxide nanowire, the diameter of the ultrafine tungsten oxide nanowire is 1-3 nm, and the length is 10-100 μm; the thickness of the photochromic layer is 1.0-1.25 μm.

6. A process for the preparation of the colorless, transparent photochromic driver according to any one of claims 1 to 5, characterized in that, comprising the following steps: preparing the second flexible optical transparent layer on a substrate; peeling the second flexible optical transparent layer from the substrate, and preparing the photochromic layer on the obtained second flexible optical transparent layer; compositing the first flexible optical transparent layer with the second flexible optical transparent layer with the photochromic layer to obtain the colorless transparent photochromic driver.

7. The method for preparing a colorless transparent photochromic driver according to claim 6, characterized in that, preparing the second flexible optical transparent layer on a substrate, comprising the following steps: adding a precursor containing a functional material of the second flexible optical transparent layer to the substrate, and heating to obtain the second flexible optical transparent layer; preparing the photochromic layer on the obtained second flexible optical transparent layer, comprising the following steps: preparing a dispersion liquid containing a functional substance of the photochromic layer; and spraying the dispersion liquid containing the functional substance of the photochromic layer on the second flexible optical transparent layer to obtain the photochromic layer; before spraying, the second flexible optical transparent layer is first bombarded by plasma.

8. Application of the colorless transparent photochromic driver of any one of claims 1-5 to an intelligent curtain.

9. An intelligent curtain, characterized in that, comprising a glass substrate and a colorless transparent photochromic driver of any one of claims 1-5 arranged on the glass substrate.

10. A method of manufacturing the intelligent window shade of claim 9, wherein, comprising the following steps: winding and fixing the colorless transparent photochromic driver to a column and placing it in an oven for heat shaping, taking a glass substrate, fixing the heat-shaped colorless transparent photochromic driver on the glass substrate to obtain the intelligent curtain.

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