Self-cleaning intelligent window with water power generation function and femtosecond laser preparation method of self-cleaning intelligent window

Abstract

The invention belongs to the technical field of intelligent building materials, and particularly relates to a self-cleaning intelligent window with a water power generation function and a femtosecond laser preparation method of the self-cleaning intelligent window. An SMP layer with a micro-column array structure is precisely machined through femtosecond laser, an electrode is integrated through a conducting medium and ITO glass, mechanical energy of raindrops and condensate drops is effectively captured in combination with a surface super-hydrophobic coating, and the mechanical energy is converted into electric energy; the self-adaptive adjustment of the light transmittance along with the temperature is realized through the phase change characteristic of the temperature-sensitive hydrogel. Through the interface coupling design of the SMP / ITO / hydrogel three-layer structure, the light transmittance dynamic regulation and control function, the environment energy recovery function and the self-cleaning function are integrated, the technical bottlenecks that a traditional intelligent window is fast in light transmittance attenuation, single in function and waste in energy are solved, and a multifunctional collaborative optimization solution is provided for building energy saving.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent building materials, and in particular relates to a self-cleaning intelligent window with hydrovoltaic power generation and a femtosecond laser preparation method thereof. Background Art

[0002] Smart window technology, a key development direction in building energy efficiency, faces a core challenge: balancing multifunctional integration with optical performance. Conventional temperature-controlled smart windows utilize thermochromic materials to adjust light transmittance, but surface contamination over time can cause transmittance degradation. Furthermore, they offer a single function and lack energy recovery. Power-generating smart windows typically incorporate a power generation layer to recycle light energy, such as depositing a cadmium telluride film between two layers of ordinary glass. However, this results in a transmittance below 70%, making it difficult to balance daylighting and power generation needs. Furthermore, the mechanical energy of droplets formed by rainfall and condensation has not been effectively captured, resulting in wasted environmental energy.

[0003] These defects seriously restrict the large-scale application of smart windows in green buildings. Therefore, there is an urgent need to develop new integrated solutions that combine dynamic control of light transmittance, environmental energy recovery and self-maintaining cleaning characteristics. Summary of the Invention

[0004] In order to solve at least one of the technical problems mentioned in the background technology, the purpose of this application is to provide a self-cleaning smart window for hydrovoltaic power generation and a femtosecond laser preparation method thereof, which can integrate dynamic control of transmittance, environmental energy recovery and self-cleaning functions into one.

[0005] The technical solution provided by the present invention is:

[0006] A self-cleaning smart window for hydrovoltaic power generation, which is a multi-layer composite structure, includes, from top to bottom, a super-hydrophobic layer, an SMP layer, an ITO conductive layer, a temperature-sensitive control layer, and an ordinary glass substrate layer. The SMP layer includes a substrate and a column array structure located on the surface of the substrate. The columns are cylinders with a diameter of 10-50 μm and a height of 50-300 μm, and the spacing between the columns is 300-500 μm. The super-hydrophobic layer is formed by a super-hydrophobic coating applied to the surface of the column array of the SMP layer, and its contact angle is greater than 150° and the rolling angle is equal to 7°. The upper surface of the ITO conductive layer is a conductive surface, and the lower surface is a non-conductive surface. The edge of the conductive surface is connected to the electrode through a conductive copper tape with a thickness of 0.1-0.3 mm, and the conductive surface is bonded to the substrate of the SMP layer. The square resistance of the ITO conductive layer is 10Ω and the transmittance is greater than 85%. The temperature-sensitive control layer is filled on the non-conductive surface of the ITO conductive layer, which is composed of a temperature-sensitive hydrogel. The thermosensitive hydrogel is a PNIPAM hydrogel composed of a NIPAM monomer and a crosslinker MBA, wherein the concentration of the NIPAM monomer is 15-25% and the amount of the crosslinker MBA added is 0.05-0.1 wt%. An ordinary glass substrate is bonded to the lower surface of the thermosensitive regulating layer.

[0007] The present invention also provides a femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window, comprising:

[0008] (1) Preparation of PTFE template: A PTFE plate is provided, and a columnar hole array is formed on one side of the PTFE plate using a femtosecond laser to obtain a PTFE template.

[0009] (2) Transfer and demolding: Inject the SMP solution composed of a mixture of epoxy resin and epoxy resin curing agent into the PTFE template so that the SMP solution completely immerses the columnar hole array and forms a base layer on the surface of the PTFE template. Then, vacuum remove the bubbles in the PTFE template; then heat and cure, and demold the SMP base and the adhered column array from the PTFE template to obtain the SMP layer.

[0010] (3) Integrated electrode: Provide ITO glass, use a conductive medium to lead out the electrode at the edge of its conductive surface, and then bond the SMP substrate to the conductive surface of the ITO glass.

[0011] (4) Assembling the temperature-sensitive layer: Fill the non-conductive surface of the ITO glass with temperature-sensitive hydrogel and then bond it to a normal glass substrate.

[0012] (5) Surface modification: A superhydrophobic coating is applied to the surface of the column array of the SMP layer to form a superhydrophobic layer.

[0013] As a further improvement of the present invention, in step (1), the wavelength of the femtosecond laser is 1030 nm, the pulse energy is 20 μJ, and the repetition frequency is 10 kHz.

[0014] As a further improvement of the present invention, in step (1), the column holes are cylindrical blind holes with a diameter of 10-50 μm, a depth of 50-300 μm, and a hole spacing of 300-500 μm.

[0015] As a further improvement of the present invention, in step (2), the amount of epoxy resin curing agent added to the SMP solution is 25 wt%.

[0016] As a further improvement of the present invention, in step (3), the square resistance of the ITO glass is 10Ω and the light transmittance is greater than 85%.

[0017] As a further improvement of the present invention, in step (3), the conductive medium is a conductive copper tape with a thickness of 0.1-0.3 mm.

[0018] As a further improvement of the present invention, the thermosensitive hydrogel is a PNIPAM hydrogel, which is composed of a NIPAM monomer and a crosslinker MBA, wherein the concentration of the NIPAM monomer is 15-25%, and the addition amount of the crosslinker MBA is 0.05-0.1 wt%.

[0019] As a further improvement of the present invention, the super hydrophobic coating is a Glaco solution.

[0020] As a further improvement of the present invention, the contact angle of the super-hydrophobic layer is greater than 150°, and the sliding angle is equal to 7°.

[0021] The technical solution provided by the present invention has the following beneficial effects:

[0022] This invention provides a self-cleaning smart window capable of hydrovoltaic power generation and a femtosecond laser fabrication method for the window. A SMP layer with a micropillar array structure is precisely machined using a femtosecond laser. A conductive medium and ITO glass integrated electrodes, combined with a surface superhydrophobic coating, effectively capture the mechanical energy of raindrops and condensation droplets, converting it into electrical energy. The phase change properties of a thermosensitive hydrogel enable adaptive temperature-dependent regulation of transmittance. The interface coupling design of the SMP / ITO / hydrogel three-layer structure integrates dynamic transmittance control, environmental energy recovery, and self-cleaning functions. This addresses the technical bottlenecks of traditional smart windows, such as rapid transmittance decay, single functionality, and energy waste, and provides a multi-functional, collaboratively optimized solution for building energy conservation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a cross-sectional view of a hydrovoltaic self-cleaning smart window provided in Example 1 of the present invention;

[0024] Figure 2 A schematic diagram of a pillar array provided in Example 1 of the present invention;

[0025] Figure 3 A schematic diagram of a droplet contact angle provided in Example 1 of the present invention;

[0026] Figure 4 A schematic diagram of droplet power generation for a self-cleaning smart window using hydrovoltaic power generation provided in Example 1 of the present invention;

[0027] Figure 5 A voltage test diagram of droplet power generation for a hydrovoltaic self-cleaning smart window provided in Example 1 of the present invention;

[0028] Figure 6 Schematic diagram of a hydrovoltaic self-cleaning smart window in low-temperature / high-temperature state provided by Example 1 of the present invention;

[0029] Figure 7 This is a transmittance curve of a hydrovoltaic self-cleaning smart window under low and high temperature conditions provided in Example 1 of the present invention;

[0030] Figure 8 A flow chart of a femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window provided in Example 2 of the present invention;

[0031] Figure 9 Schematic diagram of the preparation process of a hydrovoltaic self-cleaning smart window provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, Figure 1A cross-sectional view of a self-cleaning smart window for hydrovoltaic power generation provided in Example 1 of the present invention. The smart window is a multi-layer composite structure, which includes, from top to bottom, a super-hydrophobic layer (not shown), an SMP (Shape Memory Polymer, shape memory polymer) layer 101, an ITO (Indium Tin Oxide, indium tin oxide) conductive layer 102, a temperature-sensitive control layer 103 and a common glass substrate layer 104. Wherein, the SMP layer 101 includes a substrate and a column array structure located on the surface of the substrate. The super-hydrophobic layer is formed by a super-hydrophobic coating (such as Glaco solution) applied to the surface of the column array of the SMP layer. The upper surface of the ITO conductive layer 102 is a conductive surface, and the lower surface is a non-conductive surface. The edge of the conductive surface is drawn out by a conductive copper tape 1021 having a thickness of 0.1-0.3 mm (a thickness of 0.1 mm is taken as an example in this embodiment, which does not limit the effect), and the conductive surface of the ITO conductive layer 102 is bonded to the substrate of the SMP layer 101. The non-conductive surface of the ITO conductive layer is filled with a temperature-sensitive control layer 103, which is composed of a temperature-sensitive hydrogel. The ordinary glass substrate layer 104 is bonded to the lower surface of the temperature-sensitive control layer 103 and serves as the substrate of the entire hydrovoltaic self-cleaning smart window.

[0035] On the surface of this smart window, the micropillar array structure of the SMP layer 101 works synergistically with the superhydrophobic layer to achieve a superhydrophobic effect, preventing droplets from adhering to the surface, thereby enabling a self-cleaning function. A conductive medium and an ITO glass integrated electrode, combined with a surface superhydrophobic coating, effectively capture the mechanical energy of raindrops and condensation droplets and convert it into electrical energy. The phase change properties of the thermosensitive hydrogel enable adaptive temperature-dependent regulation of transmittance. The interface coupling design of the SMP / ITO / hydrogel three-layer structure integrates dynamic transmittance control, environmental energy recovery, and self-cleaning functions, resolving the technical bottlenecks of traditional smart windows, such as rapid transmittance decay, single functionality, and energy waste, and providing a multifunctional, collaboratively optimized solution for building energy conservation.

[0036] Specifically, a regularly arranged micro-pillar array is constructed on the surface of the SMP layer 101, and its structural parameters are precisely controlled. Figure 2 As shown, Figure 2This is a schematic diagram of a pillar array provided in Example 1 of the present invention. Each pillar is cylindrical, with a diameter of 10-50 μm and a height of 50-300 μm, and the spacing between the pillars is 300-500 μm. In a typical embodiment, the pillar diameter can be set to 30 μm and the height can be set to 50 μm (aspect ratio of 1.67), with the center-to-center spacing of adjacent micropillars being 500 μm. This slender configuration with a high aspect ratio exhibits unique mechanical advantages during the demolding process. When the peeling stress acts on the micropillars, the stress field is distributed in a gradient, with most of the stress concentrated at the base of the micropillars (the base connection) rather than being transmitted along the micropillar axis. This characteristic effectively avoids the risk of fracture in the middle of the pillar. In addition, the SMP material (epoxy resin containing 25 wt% curing agent) exhibits high toughness and moderate elasticity after curing. During demolding, the micropillars can undergo slight elastic deformation to buffer the peeling stress. The high aspect ratio micropillar array can increase the contact angle by increasing the air retention rate at the liquid-solid interface. It should be noted that, based on the same design concept, in other embodiments, the columns can also be designed as prisms, special-shaped columns, or as truncated cones, prisms, or other table shapes. These simple adjustments based on the present embodiment should still be part of the overall concept of the present embodiment.

[0037] On this basis, the contact angle can be further increased by coating the surface of the pillar array of the SMP layer 101 with Glaco solution. Figure 3 As shown, Figure 3 A schematic diagram of the contact angle of a droplet provided in Example 1 of the present invention. Through the synergistic effect of low-surface-energy chemical modification and micro-nanostructure roughening, the droplet is in the Cassie-Baxter state, i.e., the "lotus leaf state". In order to make the coating more uniform, the Glaco solution can be evenly covered on the surface of the micropillar array by spin coating, so that the contact angle of the super-hydrophobic layer is >150° and the rolling angle is 7°. In this way, pollutants are difficult to adhere to its surface, and the smart window can be tilted by 7° to achieve rainwater or condensation droplets rolling off, and when rolling off, it can carry away tiny particles such as dust on the window surface, achieving a self-cleaning effect.

[0038] Specifically, the square resistance of the ITO conductive layer 102 is 10Ω and the transmittance is greater than 85%. When raindrops hit the microcolumn surface of the SMP layer 101, due to the contact potential difference between water (low electron affinity) and the SMP material (more likely to lose electrons according to the friction sequence), electrons are transferred from the SMP surface to the droplets, resulting in the SMP surface being positively charged and the droplets being negatively charged. At this time, the ITO conductive layer under the SMP will accumulate an equal amount of negative charge to the SMP surface due to electrostatic induction, forming a built-in electric field in the vertical direction. When the droplets slide off the surface, the potential difference between the positive charge on the SMP surface and the negative charge on the ITO conductive layer 102 is released through the external circuit, generating a transient current. As Figure 4 As shown, Figure 4A schematic diagram of droplet power generation in a hydrovoltaic self-cleaning smart window, provided in Example 1 of the present invention. The upper electrode in the figure is a conductive copper tape, and the lower electrode is an electrode mounted on the surface of the hydrovoltaic smart window. When a droplet slides onto the smart window, a potential difference is created between the two electrodes, generating a transient current that, after passing through an external circuit rectifier bridge, can illuminate a load LED. The superhydrophobic layer and micropillar array structure further enhance charge separation efficiency and energy output stability by increasing the contact-separation frequency of the sliding droplet.

[0039] like Figure 5 As shown, Figure 5 This is a voltage test diagram for droplet power generation in a hydrovoltaic self-cleaning smart window, provided in Example 1 of the present invention. This diagram shows the voltage measured by an oscilloscope as droplets continuously impacted the smart window surface over 2400 seconds. The average voltage per droplet generation event reached 30 volts, demonstrating the device's excellent stability in hydrovoltaic power generation. Its energy output can meet the low-power requirements of applications such as the Internet of Things and environmental monitoring. Typical application scenarios include:

[0040] (1) Self-powered environmental monitoring: The electricity generated by the smart window directly drives the micro sensors integrated into the window, such as temperature and humidity sensors, to achieve real-time monitoring of the indoor environment; PM2.5 detection module for air quality warning;

[0041] (2) IoT node power supply: The Dickson voltage multiplier circuit converts pulse current into a stable voltage to support the following devices: wireless radio frequency tags (such as Zigbee modules) for data transmission; BLE low-power Bluetooth beacons for building positioning or asset tracking;

[0042] (3) Building security: glass breakage monitoring, piezoelectric sensors detect abnormal vibrations and trigger alarms;

[0043] (4) Emergency backup power supply: Combined with micro supercapacitor energy storage, the smart window can store electrical energy in heavy rain weather, thereby driving the LED emergency light or sending an SOS wireless signal.

[0044] In the thermosensitive control layer 103, the thermosensitive hydrogel can be a PNIPAM hydrogel, which is composed of a NIPAM monomer and a crosslinker MBA. The concentration of the NIPAM monomer is 15-25%, and the amount of the crosslinker MBA added is 0.05-0.1 wt%. In a typical embodiment, the concentration of NIPAM is 20%, and the amount of the crosslinker MBA added is 0.05 wt%. When the ambient temperature is ≥32°C (such as direct sunlight in summer), the PNIPAM hydrogel undergoes a phase transition based on the LCST (lower critical solution temperature) mechanism, changing from a transparent state to an opaque state: transmittance: 85% → 20%; reflectivity: 10% → 70%. This change can passively block more than 80% of solar radiation heat, reducing air conditioning energy consumption and achieving "smart sunshade". When the ambient temperature drops below 32°C (such as nighttime cooling or rainy weather), the PNIPAM hydrogel undergoes a reverse phase transition through the LCST mechanism, returning from an opaque state to a transparent state. Through this mechanism, the smart window automatically turns off shading mode during summer daytime and turns on daylighting mode at night or in cooler weather, achieving true environmentally adaptive intelligent control. Furthermore, this temperature-control mechanism requires no external energy or control circuitry, relying on the intrinsic properties of the material to achieve adaptive regulation. Furthermore, PNIPAM hydrogel uses water as a solvent, releasing no toxic substances.

[0045] like Figure 6 As shown, Figure 6 This is a schematic diagram of a hydrovoltaic self-cleaning smart window provided in Example 1 of the present invention in a low temperature / high temperature state. The glass of the hydrovoltaic self-cleaning smart window provided in this embodiment is placed on top of a picture. Figure 6 As can be seen in (a), when the smart window is in a low temperature state, the background pattern behind the smart window is clearly visible, indicating that the smart window has good optical transmittance at low temperatures; Figure 6 As can be seen in (b), when the smart window is in a high temperature state, that is, the hydrogel layer in the smart window undergoes a phase change after exceeding the lower critical solution temperature of 32°C, changing from transparent to pure white opaque state, which verifies that the smart window has the function of regulating in-situ optical transmittance. It should be noted that Figure 6 The background pattern in the image is only used to illustrate whether the pattern will be blocked by the smart window glass.

[0046] like Figure 7 As shown, Figure 7 This is the transmittance curve of a hydrovoltaic self-cleaning smart window under low and high temperature conditions provided in Example 1 of the present invention. Figure 7 It reflects that at low temperatures, the smart window can reach 85% in the visible light band, with good optical transmittance, while at high temperatures, the optical transmittance in the visible light band drops to about 25%, proving that the smart window has excellent performance in in-situ regulation of optical transmittance.

[0047] Example 2

[0048] See also Figure 8 and Figure 9 , Figure 8 This is a flow chart of a femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window provided in Example 2 of the present invention. Figure 9 This is a schematic diagram of a process for preparing a hydrovoltaic self-cleaning smart window provided in Example 2 of the present invention. The method comprises the following steps:

[0049] (1) Preparation of PTFE template: A PTFE plate is provided, and a columnar hole array is formed on one side of the PTFE plate using a femtosecond laser to obtain a PTFE template.

[0050] (2) Transfer and demolding: Inject the SMP solution composed of a mixture of epoxy resin and epoxy resin curing agent into the PTFE template so that the SMP solution completely immerses the columnar hole array and forms a base layer on the surface of the PTFE template. Then, vacuum remove the bubbles in the PTFE template; then heat and cure, and demold the SMP base and the adhered column array from the PTFE template to obtain the SMP layer.

[0051] (3) Integrated electrode: Provide ITO glass, use a conductive medium to lead out the electrode at the edge of its conductive surface, and then bond the SMP substrate to the conductive surface of the ITO glass.

[0052] (4) Assembling the temperature-sensitive layer: Fill the non-conductive surface of the ITO glass with temperature-sensitive hydrogel and then bond it to a normal glass substrate.

[0053] (5) Surface modification: A superhydrophobic coating is applied to the surface of the column array of the SMP layer to form a superhydrophobic layer.

[0054] In order to further introduce the specific process adopted by the preparation method, the above steps are described in detail below:

[0055] First, a femtosecond laser system with a wavelength of 1030nm is used to perform microstructure processing on a PTFE substrate. The pulse energy is set to 20μJ and the repetition rate is 10kHz. By precisely controlling the laser focus, an array of cylindrical blind holes with a hole diameter of 10-50μm and a hole depth of 50-300μm is formed on the substrate surface, with a hole spacing of 300-500μm. In a typical embodiment, a cylindrical blind hole array with a hole diameter of 30μm and a hole depth of 50μm can be formed, with a hole spacing of 500μm. Compared with traditional photolithography or chemical etching processes, this femtosecond laser processing technology not only avoids chemical contamination, but also improves processing accuracy to ±1μm and improves efficiency by 5 times. The specially designed blind hole structure does not require a glass substrate for support during the subsequent transfer process. Thanks to the inherent low surface energy characteristics of the PTFE material, it can effectively reduce the adhesion force at the demolding interface. If a through-hole structure is used, the template must be fixed to the glass substrate. In this case, demolding must simultaneously overcome the dual interface resistance between the SMP and PTFE and the SMP and glass, resulting in a decrease in yield.

[0056] After the template is prepared, epoxy resin E51 (618) and 25 wt% triethylenetetramine (TETA) curing agent are mixed into a SMP solution and injected into the PTFE template. -3 MPa) to ensure the SMP solution fully fills the blind hole array, followed by curing at 80°C for 4 hours to form an SMP micropillar structure with both high toughness and moderate elasticity. During this process, the slender micropillars with an aspect ratio of 1.67 dissipate peeling energy through a synergistic mechanism of root stress concentration and elastic deformation of the material, achieving a demolding yield of 97%. The cured micropillar array's three-dimensional roughness improves air retention at the liquid-solid interface, thereby increasing the contact angle.

[0057] During the electrode integration stage, ITO glass with a square resistance of 10Ω and a transmittance of >85% is selected as the conductive substrate. Its single-sided conductive properties are achieved through an ITO coating with a thickness of 100-300nm, while the non-conductive surface maintains the intrinsic insulating properties of the glass. A 0.1-0.3mm thick nickel-plated copper tape is used as the conductive medium, and in typical cases, a 0.1mm conductive copper tape is used to lead out the electrodes along the edge of the ITO conductive surface. This design uses flexible tape to achieve precise fitting of irregular edges, ensuring that the light-transmitting area is unobstructed while forming a smooth stress transition between the ITO conductive layer and the SMP layer, avoiding interface delamination caused by local stress concentration.

[0058] The construction of the thermosensitive functional layer is achieved by filling the non-conductive surface of the ITO glass with PNIPAM hydrogel, which is composed of NIPAM monomer and crosslinker MBA, where the concentration of NIPAM monomer is 15-25% and the addition amount of crosslinker MBA is 0.05-0.1wt%. In a typical case, a NIPAM monomer solution with a prepolymer concentration of 20% is copolymerized with 0.05wt% crosslinker MBA to form a three-dimensional network structure with temperature-responsive characteristics. When the ambient temperature exceeds 32°C, the hydrogel undergoes a phase transition based on the LCST mechanism, and the transmittance drops sharply from 85% to 20%, while the reflectivity increases to 70%, which can block more than 80% of solar radiation heat. This passive control mechanism allows the smart window to automatically turn on the sunshade mode during the day in summer and return to the transparent state when the temperature drops at night. The entire process does not require external energy supply, and the use of water as a solvent prevents the release of toxic substances.

[0059] Finally, a superhydrophobic coating of Glaco solution was constructed on the surface of the SMP micropillars via a spin-coating process. The fluorosilane compound formed a low-surface-energy chemical layer (surface energy 12 mN / m) on the micropillar surface, which synergistically induced a Cassie-Baxter wetting state with the micro-nanostructure with an aspect ratio of 1.67. The modified surface achieved a contact angle greater than 150° and a rolling angle ≤7°, allowing rainwater or condensation droplets to roll off at a 7° inclination angle, carrying away surface contaminants and achieving efficient self-cleaning.

[0060] This embodiment provides a femtosecond laser fabrication method for a hydrovoltaic self-cleaning smart window. Using femtosecond laser precision machining, a SMP layer with a micropillar array structure is formed. A conductive medium and ITO glass integrated electrode, combined with a surface superhydrophobic coating, effectively capture the mechanical energy of raindrops and condensation droplets, converting it into electrical energy. The phase change properties of a thermosensitive hydrogel enable adaptive temperature-dependent regulation of transmittance. The interface coupling design of the SMP / ITO / hydrogel three-layer structure integrates dynamic transmittance control, environmental energy recovery, and self-cleaning functions. This addresses the technical bottlenecks of traditional smart windows, such as rapid transmittance decay, single functionality, and energy waste, and provides a multifunctional, collaboratively optimized solution for building energy conservation.

[0061] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in the present invention can be achieved, and this document does not limit this. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A hydrovoltaic self-cleaning smart window, characterized in that: It is a multi-layer composite structure, which includes a super-hydrophobic layer, an SMP layer, an ITO conductive layer, a temperature-sensitive control layer and an ordinary glass substrate layer from top to bottom. The SMP layer includes a substrate and a column array structure located on the surface of the substrate, wherein the columns are cylinders with a diameter of 10-50 μm and a height of 50-300 μm, and a spacing between the columns is 300-500 μm; The super-hydrophobic layer is formed by a super-hydrophobic coating applied to the surface of the pillar array of the SMP layer, and has a contact angle greater than 150° and a rolling angle equal to 7°; The ITO conductive layer has a conductive upper surface and a non-conductive lower surface. The edge of the conductive surface is connected to the electrode through a conductive copper tape with a thickness of 0.1-0.3 mm. The conductive surface is bonded to the base of the SMP layer. The sheet resistance of the ITO conductive layer is 10Ω and the transmittance is greater than 85%. The thermosensitive regulating layer is filled on the non-conductive surface of the ITO conductive layer and is composed of a thermosensitive hydrogel; the thermosensitive hydrogel is a PNIPAM hydrogel, which is composed of a NIPAM monomer and a crosslinker MBA, wherein the concentration of the NIPAM monomer is 15-25%, and the amount of the crosslinker MBA added is 0.05-0.1wt%; The ordinary glass base layer is bonded to the lower surface of the temperature-sensitive regulating layer.

2. A femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window, characterized in that: include: (1) Preparation of PTFE template: providing a PTFE plate, and forming a columnar hole array on one side of the PTFE plate using a femtosecond laser to obtain a PTFE template; (2) Transfer and demolding: Inject the SMP solution composed of a mixture of epoxy resin and epoxy resin curing agent into the PTFE template so that the SMP solution completely immerses the columnar pore array and forms a base layer on the surface of the PTFE template, and then vacuum removes the bubbles in the PTFE template; Heat and cure, and demold the SMP substrate and the bonded pillar array from the PTFE template to obtain an SMP layer; (3) Integrated electrode: Provide ITO glass, use a conductive medium to lead out the electrode at the edge of its conductive surface, and then bond the SMP substrate to the conductive surface of the ITO glass; (4) Assembling the temperature-sensitive layer: filling the non-conductive surface of the ITO glass with a temperature-sensitive hydrogel and bonding it to a normal glass substrate; (5) Surface modification: A superhydrophobic coating is applied to the surface of the column array of the SMP layer to form a superhydrophobic layer.

3. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: In step (1), the wavelength of the femtosecond laser is 1030 nm, the pulse energy is 20 μJ, and the repetition frequency is 10 kHz.

4. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: In step (1), the column holes are cylindrical blind holes with a diameter of 10-50 μm, a depth of 50-300 μm, and a hole spacing of 300-500 μm.

5. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: In step (2), the amount of epoxy resin curing agent added to the SMP solution is 25 wt%.

6. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: In step (3), the ITO glass has a square resistance of 10Ω and a light transmittance greater than 85%.

7. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: In step (3), the conductive medium is a conductive copper tape with a thickness of 0.1-0.3 mm.

8. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: The thermosensitive hydrogel is a PNIPAM hydrogel, which is composed of a NIPAM monomer and a cross-linking agent MBA, wherein the concentration of the NIPAM monomer is 15-25%, and the addition amount of the cross-linking agent MBA is 0.05-0.1 wt%.

9. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: The super hydrophobic coating is a Glaco solution.

10. The femtosecond laser preparation method for a hydrovoltaic self-cleaning smart window according to claim 2, characterized in that: The contact angle of the super-hydrophobic layer is greater than 150°, and the sliding angle is equal to 7°.

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