A hydrogel for smart windows and its preparation method and application

Abstract

The present invention discloses a hydrogel for smart windows, its preparation method, and application, belonging to the technical field of energy-saving windows for buildings. The hydrogel comprises the following raw materials, by weight: gelatin: 0.1 parts to 1.0 parts, polyvinyl alcohol: 5 parts to 6 parts, dimethyl sulfoxide: 30 parts to 40 parts, sodium chloride: 0.5 parts to 1.0 parts, ferrous chloride tetrahydrate: 0.15 parts to 0.25 parts, hydrochloric acid: 0.5 parts to 1.5 parts, ferric chloride hexahydrate: 0.20 parts to 0.30 parts, and deionized water: 5 parts to 15 parts. The prepared smart window has excellent light and heat regulation performance, can achieve a comfortable indoor temperature, and self-generation provides support for the engineering application of the smart window, realizes the rational use of temperature differences, and effectively reduces people's living costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of building energy-saving windows, and specifically relates to a hydrogel for smart windows and a preparation method and application thereof. Background Art

[0002] Traditional windows cause 30% energy loss, leading to the development of energy-saving windows. Research on energy-saving windows has primarily focused on color rendering technology. Existing electrochromic and thermochromic smart windows essentially achieve energy savings by regulating sunlight to control indoor temperature. However, this process doesn't effectively utilize solar radiation. Existing smart windows experience significant heat loss from both incident and reflected sunlight, and the generated heat energy isn't effectively utilized.

[0003] In addition to the energy-saving smart windows mentioned above, some smart windows also have specific functions, such as automatically opening and closing in response to environmental changes, alarming when a fire occurs indoors, and displaying the temperature in a frozen storage room or alarming when the temperature is abnormal. These smart windows require external power. Currently, the common approach is to reserve a power jack next to the smart window or rewire the wiring. This not only creates an unsightly interior, but also renders these functions inoperable when the external power source suddenly fails. Compared to smart windows with external power, solar-powered smart windows use solar panels to absorb solar energy and convert it into electricity to power the smart window. However, this power supply method is affected by rainy weather and poor sunlight in buildings. Furthermore, the cost of installing solar panels is high, and window installation is inconvenient. In recent years, research has been conducted on materials with electrochromic properties. For example, patent CN 110501852A discloses an electrochromic device based on a highly concentrated aqueous electrolyte and its preparation method. The cavity is filled with a highly concentrated aqueous electrolyte (a fluorine-containing lithium salt aqueous solution with a concentration of 13 to 21 mol / L). However, the high volatility of highly concentrated aqueous electrolytes and the high manufacturing cost of electrical equipment have limited their application. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a smart window that can achieve energy-saving effects by regulating sunlight and generate electricity by utilizing the temperature gradient formed. This avoids the problems of external power supply, installation of solar panels, or power failure due to continuous rainy days, realizes the rational use of temperature difference, and effectively reduces people's living costs.

[0005] 2. Technical solution

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A hydrogel for smart windows,

[0008] In parts by weight, it includes the following raw materials:

[0009]

[0010] The hydrogel for smart window as described,

[0011] In parts by weight, it includes the following raw materials:

[0012]

[0013] The preparation method of the hydrogel for smart window as described above,

[0014] The following steps are involved:

[0015] First, gelatin is dissolved in deionized water and stirred at 50°C-70°C for 2h-4h to obtain a gelatin solution; then, polyvinyl alcohol is dissolved in dimethyl sulfoxide and stirred at 90°C-100°C for 1h-3h to obtain a viscous and uniform solution; then, sodium chloride, ferrous chloride tetrahydrate, and ferric chloride hexahydrate are prepared and mixed evenly with the above-mentioned viscous and uniform solution, and then hydrochloric acid is added, cooled to 50°C-70°C, and mixed with the above-mentioned gelatin solution to obtain a mixed solution; finally, poured into a mold, cooled to room temperature, and then completely cross-linked at -20°C until a hydrogel is formed.

[0016] The above hydrogel is used in the production of smart windows.

[0017] The hydrogel described above is used in the production of smart windows.

[0018] Prepare multiple window panels with intervals, form a cavity for accommodating the hydrogel between adjacent window panels, seal the four sides of the cavity and leave an injection port, inject the prepared hydrogel into the cavity through the injection port, and seal the injection port of the cavity.

[0019] The hydrogel described above is used in the production of smart windows.

[0020] The thickness of the cavity is 0.01mm-15mm;

[0021] The window panel is made of transparent glass or plastic.

[0022] The hydrogel described above is used in the production of smart windows.

[0023] The number of the window panels is at least two, and a first window panel and a third window panel are provided;

[0024] The first window panel and the third window panel adjacent to each other are sealed to form a first cavity; the third window panel faces outdoors, and the first window panel faces indoors;

[0025] The first cavity is used for infusing the first hydrogel, wherein the first hydrogel is the hydrogel prepared by the above preparation method.

[0026] The hydrogel described above is used in the production of smart windows.

[0027] A second window panel is also provided, and a second cavity is formed by sealing between the adjacent first window panel and the second window panel;

[0028] The second cavity is used to perfuse the second hydrogel, wherein the second hydrogel is a thermochromic temperature-sensitive hydrogel added with light-absorbing nanoparticles, and the minimum critical temperature of the thermochromic temperature-sensitive hydrogel during use is 20° C.-50° C.;

[0029] The light-absorbing nanoparticles are one or a mixture of graphene, gold nanoparticles, and MXene, and the final mass percentage after addition is 0.05 wt %. MXene is selected in specific use.

[0030] The thermochromic temperature-sensitive hydrogel with added light-absorbing nanoparticles comprises the following raw materials in parts by weight:

[0031]

[0032] The preparation method of the thermochromic temperature-sensitive hydrogel with added light-absorbing nanoparticles is as follows:

[0033] Add poly(vinyl pyrrolidone), N-isopropylacrylamide, and N,N'-methylenebis(acrylamide) to deionized water, and stir the mixture at 40°C-60°C until a transparent solution is formed to ensure complete dissolution; then, transfer the transparent solution to an oil bath and heat to 50°C-70°C under a nitrogen atmosphere; then add potassium persulfate to a final concentration of 0.01 g / ml, and continue polymerization under a nitrogen atmosphere for 18 hours-36 hours; finally, cool to room temperature, collect, and store.

[0034] The hydrogel described above is used in the production of smart windows.

[0035] It also includes energy storage systems;

[0036] The inner side surface of the first window panel and the opposite inner side surface of the third window panel are both coated with a conductive material to form an electrode base. The electrode base is connected to the energy storage system through electrodes, and the energy storage system is connected to an alarm device or a temperature display device in a frozen storage room.

[0037] Beneficial effects

[0038] The present invention accelerates the thermochromic thermosensitive hydrogel and light-to-heat conversion capability by adding an appropriate amount of nanoparticles to the thermochromic thermosensitive hydrogel (lower critical solution temperature of 20°C-55°C) encapsulated in the second cavity. Rapid thermochromism can achieve indoor temperature regulation and achieve energy-saving effects. At the same time, the temperature of the intermediate interlayer window panel is rapidly adjusted. There is a temperature gradient between the temperature of the outdoor window panel and the intermediate interlayer window panel. The transparent thermoelectric hydrogel encapsulated in the first cavity undergoes an iron ion redox reaction, and the migration of positive and negative ions generates a potential difference and generates current. The inner sides of the window panels on both sides of the transparent thermoelectric hydrogel are coated with a conductive material as an electrode substrate, or two conductive glass panels are directly connected to the energy storage system. The energy storage system is connected to an alarm device or a temperature display device in a refrigerated storage room to provide power. The transparent thermoelectric hydrogel is used in the first layer of hydrogel and is completely sealed between two layers of glass. The inner sides of the window panels in the second cavity (i.e., the inner sides of the window panels on both sides of the transparent thermoelectric hydrogel) are coated with a conductive material as an electrode substrate. Electrodes are connected to the electrode substrate and are connected to the energy storage system. Alternatively, conductive glass can be directly installed on both window panels. With no contact with air, the hydrogel's moisture will not evaporate or be lost. The second layer of hydrogel changes color more evenly, without layered lines. Adding a small amount of nanoparticles accelerates the hydrogel's thermochromic response time and improves its light-to-heat conversion performance. Even if the thermochromic glass is physically damaged, it will still maintain stable color change. The transparent thermoelectric hydrogel in the first layer and the thermochromic temperature-sensitive hydrogel in the second layer both enhance the smart window's flame retardancy, preventing fires. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the present invention;

[0040] Figure 2 Schematic diagram of a temperature-sensitive amide hydrogel prepared in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of a transparent thermoelectric hydrogel;

[0042] Figure 4 The current-voltage curves of the smart window prepared by the present invention at temperature differences of 10°C, 20°C, and 40°C are shown;

[0043] Figure 5 is the output power of the smart window prepared by the present invention at temperature differences of 10°C, 20°C and 30°C;

[0044] Figure 6 The current-voltage curves measured on the titanium plate and titanium mesh during the discharge process of the smart window of the present invention are:

[0045] Figure 7 is the dependence of the output voltage of the smart window of the present invention on the external temperature difference;

[0046] Figure 8 This is a schematic diagram of the principle of the transparent thermoelectric hydrogel of the present invention generating electricity under temperature difference;

[0047] Figure 9 This is a rendering of the mechanical structure of the smart window of the present invention;

[0048] Figure 10 This is a rendering of the application of the smart window of the present invention in daily life;

[0049] Figure 11 This is a building curtain wall effect diagram of the smart window application life of the present invention.

[0050] In the figure: 1-first cavity, 2-second cavity, 3-energy storage system, 4-window body, 41-first window panel, 42-second window panel, 43-third window panel, 5-electrode substrate, 6-temperature display device. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention are described in detail below. The described embodiments are only some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art fall within the scope of protection of the present invention. The present invention is further described below in conjunction with specific embodiments.

[0052] Example 1

[0053] The hydrogel for smart windows comprises the following raw materials, in parts by weight:

[0054]

[0055] A method for preparing a hydrogel for a smart window comprises the following steps:

[0056] First, gelatin is dissolved in deionized water and stirred at 50°C-70°C for 2h-4h to obtain a gelatin solution; then, polyvinyl alcohol is dissolved in dimethyl sulfoxide and stirred at 90°C-100°C for 1h-3h to obtain a viscous and uniform solution; then, sodium chloride, ferrous chloride tetrahydrate, and ferric chloride hexahydrate are prepared and mixed evenly with the above-mentioned viscous and uniform solution, and then hydrochloric acid is added, cooled to 50°C-70°C, and mixed with the above-mentioned gelatin solution to obtain a mixed solution; finally, poured into a mold, cooled to room temperature, and then completely cross-linked at -20°C until a hydrogel is formed.

[0057] In actual application, the operation is as follows:

[0058] like Figure 3As shown, the preparation of hydrogel (transparent thermoelectric hydrogel): first, 0.5g gelatin was dissolved in 9ml deionized water and magnetically stirred at 60℃ for 3h to obtain a gelatin solution; 5.5g polyvinyl alcohol was dissolved in 35g dimethyl sulfoxide solution and magnetically stirred at 95℃ for 2h to obtain a viscous and uniform solution; then 0.8766g NaCl, 0.1988g FeCl2*H2O and 0.2703g FeCl3*H2O were added, and 1mL HCl was added, and then mixed with the gelatin solution, and finally poured into a polytetrafluoroethylene mold. After cooling to room temperature, the freeze-thaw method was applied to a -20℃ environment for complete cross-linking until the transparent thermoelectric hydrogel was formed.

[0059] Example 2

[0060] Application of hydrogel in the production of smart windows.

[0061] like Figure 1 As shown, multiple window panels are prepared at intervals, with a cavity for accommodating the hydrogel formed between adjacent window panels. The cavity is sealed around the periphery and an injection port is left. The prepared hydrogel is injected into the cavity through the injection port, and the injection port is sealed. The thickness of the cavity is 0.01mm-15mm (3mm is selected in this embodiment);

[0062] The window panel is made of transparent glass or plastic, wherein the transparent glass is one of borosilicate glass, glass-ceramic, and tempered glass, and the plastic is one of polypropylene, polycarbonate, and polyvinyl chloride. In this application, the window panel is made of borosilicate glass.

[0063] The number of the window panels is at least two, and a first window panel 41 and a third window panel 43 are provided;

[0064] The first window panel 41 and the third window panel 43 adjacent to each other are sealed to form a first cavity 1; the third window panel 43 faces the outside, and the first window panel 41 faces the inside.

[0065] The first cavity 1 is used for infusing the first hydrogel, wherein the first hydrogel is the hydrogel prepared by the preparation method according to claim 3.

[0066] A second window panel 42 is further provided, and the adjacent first window panel 41 and the second window panel 42 are sealed to form a second cavity 2;

[0067] The second cavity 2 is used to infuse the second hydrogel, wherein the second hydrogel is a thermochromic thermosensitive hydrogel with light-absorbing nanoparticles added thereto, and the lower critical solution temperature of the thermochromic thermosensitive hydrogel is 29° C. when in use;

[0068] The light-absorbing nanoparticles are MXene, and the final mass percentage after addition is 0.05 wt%;

[0069] The thermochromic temperature-sensitive hydrogel with added light-absorbing nanoparticles comprises the following raw materials in parts by weight:

[0070]

[0071] In addition, the thermochromic temperature-sensitive hydrogel can also be designed to be one or a mixture of poly(N-isopropylacrylamide), acrylamide, and poly(vinylcaprolactam).

[0072] In specific applications, the operations are as follows:

[0073] The preparation method of the thermochromic temperature-sensitive hydrogel with added light-absorbing nanoparticles is as follows:

[0074] Add poly (vinyl pyrrolidone), N-isopropylacrylamide, N, N'methylenebis (acrylamide) to deionized water, stir the mixture at 40 ℃ -60 ℃ until a transparent solution is formed to ensure complete dissolution; then, transfer the transparent solution to an oil bath and heat it to 50 ℃ -70 ℃ under a nitrogen atmosphere; then add potassium persulfate and continue to polymerize under a nitrogen atmosphere for 18h -36h; finally, cool to room temperature, collect, and store. Specifically, if Figure 2 As shown in FIG, the preparation method of the thermochromic temperature-sensitive hydrogel is as follows: 0.05 g of poly(vinyl pyrrolidone), 2.5 g of N-isopropylacrylamide and 0.05 g of N,N′-methylenebis(acrylamide) components are added to 100 g of water; the mixture is stirred at 50° C. until a transparent solution is formed to ensure complete dissolution; the solution is then transferred to a three-necked flask and the flask is placed in an oil bath; thereafter, the reaction mixture is heated to 60° C. under a nitrogen flow; potassium persulfate at a concentration of 0.05 g / ml is subsequently added, and polymerization is carried out under a nitrogen atmosphere for 24 hours; the final product is naturally cooled to room temperature and collected in a transparent glass bottle.

[0075] In addition, it also includes an energy storage system 3;

[0076] The inner side of the first window panel 41 and the opposing inner side of the third window panel 43 are both coated with a conductive material to form an electrode substrate 5. The electrode substrate 5 is connected to the energy storage system 3 via electrodes, and the energy storage system 3 is connected to an alarm device or a temperature display device 6 within the refrigerated storage compartment. It should be noted that the first window panel 41 can be directly mounted with conductive glass to connect to the energy storage system 3. The energy storage system 3 can be provided with multiple output terminals, each of which is connected to an electrical device. The energy storage system 3 can be a battery.

[0077] After the application of the above smart window, a new type of smart window with both power generation and energy saving is obtained, and its technical indicators are as follows:

[0078] like Figure 4 As shown in Figure 2, the voltages of the smart window at 10°C, 20°C, and 30°C are 16MV, 33MV, and 64MV, respectively. Figure 5 The output power of the smart window at temperature differences of 10°C, 20°C, and 30°C is shown in the figure. This output power data fully demonstrates the excellent power generation efficiency of the present invention. The voltages at temperature gradients of 10°C, 20°C, and 30°C are 16MV, 33MV, and 64MV, respectively. When connected in series or parallel, the devices can basically meet the switching needs of small electrical appliances.

[0079] like Figure 6 As shown, the current-voltage curves measured on the titanium plate and mesh during the smart window discharge process show that both voltage and current increase at 2.2C. In actual applications, the voltage and current on the titanium plate and mesh demonstrate a robust discharge process. Compared to more stable power generation devices, the discharge process of the present invention is continuously enhanced, capable of higher power output.

[0080] like Figure 7 As shown in the figure, the output voltage of the smart window gradually increases with the applied temperature difference. Since the present invention relies heavily on the temperature difference, but the size of the temperature gradient also determines the voltage, this is a self-generating capability. This self-generating smart window can better demonstrate energy-saving effects.

[0081] like Figure 8 As shown in the figure, when the temperature of the transparent thermoelectric hydrogel is kept constant by a constant temperature water pump at the bottom, the temperature difference is controlled by heating one end with a solar lamp. The thermoelectric hydrogel realizes the transfer of electrons through the different temperature differences on the positive and negative sides; it embodies the principle of self-generation, and when the temperature difference is sufficient, the desired voltage value can be obtained and the output can be stable.

[0082] like Figure 9 As shown in the figure, the voltage of five transparent thermoelectric hydrogels (10mm*10mm*10mm) connected in series in outdoor environment reaches 85MV. Figure 11 In the building curtain walls, we can obtain more stable and efficient voltage.

[0083] like Figure 10 and Figure 11The figure shows the effect of the invented device in real life. When the sunlight continues to irradiate, the second layer of hydrogel quickly absorbs heat and the thermochromic structure blocks the sunlight. At this time, there is a temperature difference between the outdoor glass temperature and the second layer of glass, so the Fe ions in the first layer of hydrogel undergo redox reaction. When the temperature gradient is established, electron transfer occurs, causing the electrode potential to increase and the electrochemical potential to decrease. At the cold end of the indoor glass, the same redox reaction and electron transfer, as well as the increase of electrochemical potential and the decrease of electrode potential, also occur. Oxidized Fe 3+ Ions are transferred to the high temperature electrode by convection, diffusion and migration, and the reduced Fe 2+ The ions then return to the low-temperature electrode for a continuous reaction. Thus, a voltage is generated quasi-continuously between the two electrodes along the temperature gradient, while the room temperature is maintained at a comfortable temperature due to the thermochromic properties of the second hydrogel layer.

[0084] The above is a schematic description of the present invention and its embodiments. This description is not restrictive and only illustrates one embodiment of the present invention. The actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without creatively designing them, they shall fall within the scope of protection of the present invention.

Claims

1. A hydrogel for smart windows, characterized by: In parts by weight, it includes the following raw materials: Gelatin 0.1-1.0 parts, 5-6 parts of polyvinyl alcohol, 30-40 parts of dimethyl sulfoxide, Sodium chloride 0.5 parts to 1.0 parts, 0.15-0.25 parts of ferrous chloride tetrahydrate, 0.5-1.5 parts of hydrochloric acid, 0.20-0.30 parts of ferric chloride hexahydrate, 5-15 parts deionized water; A method for preparing a hydrogel for a smart window comprises the following steps: First, gelatin is dissolved in deionized water and stirred at 50°C-70°C for 2h-4h to obtain a gelatin solution; then, polyvinyl alcohol is dissolved in dimethyl sulfoxide and stirred at 90°C-100°C for 1h-3h to obtain a viscous and uniform solution; then, sodium chloride, ferrous chloride tetrahydrate, and ferric chloride hexahydrate are prepared and mixed evenly with the above-mentioned viscous and uniform solution, and then hydrochloric acid is added, cooled to 50°C-70°C, and mixed with the above-mentioned gelatin solution to obtain a mixed solution; finally, poured into a mold, cooled to room temperature, and then completely cross-linked at -20°C until a hydrogel is formed.

2. The hydrogel for smart window according to claim 1, characterized in that: In parts by weight, it includes the following raw materials: 0.5 parts of gelatin, 5.5 parts of polyvinyl alcohol, 35 parts of dimethyl sulfoxide, 0.8766 parts of sodium chloride, 0.1988 parts of ferrous chloride tetrahydrate, 1 part hydrochloric acid, 0.2703 parts of ferric chloride hexahydrate, 9 parts of deionized water.

3. Use of the hydrogel according to claim 1 or 2 in the production of smart windows.

4. The hydrogel according to claim 3 is used in the production of smart windows, characterized in that: Prepare multiple window panels with intervals, form a cavity for accommodating the hydrogel between adjacent window panels, seal the four sides of the cavity and leave an injection port, inject the prepared hydrogel into the cavity through the injection port, and seal the injection port of the cavity.

5. The hydrogel according to claim 4 is used in the production of smart windows, characterized in that: The thickness of the cavity is 0.01mm-15mm; The window panel is made of transparent glass or plastic.

6. The hydrogel according to claim 5 is used in the production of smart windows, characterized in that: The number of the window panels is at least two, and a first window panel (41) and a third window panel (43) are provided; A first cavity (1) is formed by sealing between the adjacent first window panel (41) and the third window panel (43); the third window panel (43) faces the outside, and the first window panel (41) faces the inside; The first cavity (1) is used for infusing a first hydrogel, wherein the first hydrogel is the hydrogel according to claim 1 or 2.

7. The hydrogel according to claim 6 is used in the production of smart windows, characterized in that: A second window panel (42) is also provided, and the adjacent first window panel (41) and the second window panel (42) are sealed to form a second cavity (2); The second cavity (2) is used to perfuse the second hydrogel, wherein the second hydrogel is a thermochromic temperature-sensitive hydrogel with light-absorbing nanoparticles added thereto, and the lowest critical temperature of the thermochromic temperature-sensitive hydrogel during use is 20°C-50°C; The light-absorbing nanoparticles are one or a mixture of graphene, gold nanoparticles, and MXene, and the final mass percentage after addition is 0.05wt%; The thermochromic temperature-sensitive hydrogel with added light-absorbing nanoparticles further comprises the following raw materials in parts by weight: 80-120 parts of deionized water, Poly(vinyl pyrrolidone) 0.01 part to 0.10 part, N-isopropylacrylamide 2.0 parts to 3.0 parts, 0.01-0.10 parts of N,N'-methylenebisacrylamide.

8. The hydrogel according to claim 7 is used in the production of smart windows, characterized in that: It also includes energy storage systems (3); The inner side surface of the first window panel (41) and the inner side surface opposite to the third window panel (43) are both coated with a conductive material to form an electrode base (5). The electrode base (5) is connected to the energy storage system (3) via electrodes, and the energy storage system (3) is connected to an alarm device or a temperature display device (6) in a refrigerated storage room.

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