A method for constructing smart hydrogel in double-layer insulating glass and smart hydrogel

Abstract

The present invention relates to a method for constructing a smart hydrogel in double-layer insulating glass, and the smart hydrogel. First, a methacrylated hyaluronic acid solution and a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide are prepared, and N,N,N',N'-tetramethylethylenediamine is added. The mixture is then ultrasonically dispersed to obtain a uniform dispersion. The monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide is thoroughly mixed with the methacrylated hyaluronic acid solution. Ammonium persulfate is added to the mixture, and the mixture is quickly transferred to a double-layer insulating glass mold. The smart hydrogel is then prepared in a super-constant temperature water bath. Compared with the prior art, the preparation method of the present invention is significantly simpler and reduces manufacturing costs. The thermochromic temperature of the smart hydrogel can be accurately controlled by adjusting the concentration of the methacrylated hyaluronic acid and the synthesis temperature. The hydrogel has excellent moisture retention properties, exhibits no significant shrinkage after multiple cycles, and exhibits excellent structural robustness.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material preparation, and in particular to a method for constructing smart hydrogel in double-layer insulating glass and the smart hydrogel. Background Art

[0002] Buildings rely on temperature regulation systems, which in turn creates a demand for energy.

[0003] As the primary medium for heat exchange between indoors and outdoors, windows play a crucial role in energy conservation. However, traditional windows often lack the ability to adapt to changing environmental conditions, resulting in significant energy inefficiencies. In contrast, smart windows can dynamically adapt to various stimuli, including humidity, electricity, and heat fluctuations, proactively regulating the transmission or reflection of sunlight. This adaptive capability not only helps stabilize indoor temperatures but also improves visual comfort, thereby enhancing the overall energy efficiency of a building.

[0004] Thermochromic hydrogels are temperature-sensitive materials whose physical properties undergo reversible changes with temperature. They have broad applications in a variety of fields, including medical dressings, thermal sensors, and energy-saving devices. Poly(N-isopropylacrylamide) hydrogel (PNIPAm hydrogel) is a particularly noteworthy thermochromic material, which is highly sensitive to temperature changes. At its lower critical solution temperature (typically around 32°C), it undergoes a dramatic transition from transparent to opaque, triggered by phase separation of the polymer. Below the liquidus temperature (LCST), the polymer chains are dissolved by water molecules, maintaining a transparent hydrated state with good optical transmittance. To enhance the performance of poly(N-isopropylacrylamide) hydrogels, they have been integrated into composites with other polymers, nanoparticles, and metal-organic frameworks. However, this approach faces challenges associated with physical doping, primarily because doping inevitably degrades optical properties or raises the critical temperature, limiting its application in smart devices.

[0005] Smart gels are gels that respond sensitively to external stimuli, exhibiting absorbency and sustained-release properties. Modification of poly(N-isopropylacrylamide) hydrogels can further enhance their performance. For example, CN114702693A discloses a synthesis method and application of a trehalose-modified PNIPAm thermosensitive smart hydrogel. Trehalose-modified PNIPAm thermosensitive smart materials exhibit advantages such as high mechanical strength, rapid thermal response, minimal volume change, and low energy consumption. However, their environmental stability and biodegradability remain to be explored. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for constructing smart hydrogels in double-layer insulating glass and smart hydrogels in order to solve the above-mentioned problems. In order to address the shortcomings of hydrogels with poor optical properties and excessively high thermochromic temperatures, the present invention provides a method for constructing smart hydrogels in double-layer insulating glass with accurately adjustable phase transition temperature, high light transmittance, high solar energy regulation efficiency and good stability; and a smart hydrogel obtained by this method with accurately adjustable phase transition temperature, high light transmittance, high solar energy regulation efficiency and good stability.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A first object of the present invention is to provide a method for constructing a smart hydrogel in a double-layer insulating glass, the method comprising the following steps:

[0009] (1) dissolving methacrylic anhydride and hyaluronic acid in deionized water, cooling the solution to 0-4 degrees Celsius to obtain solution A, and adding sodium hydroxide solution dropwise to solution A to adjust the pH to 9-10; after the addition is completed, stirring the resulting solution at 0-4 degrees Celsius, dialyzing the solution with deionized water at 4 degrees Celsius, and freeze-drying the solution after dialysis to obtain a solid of methacrylated hyaluronic acid; and dissolving the solid in deionized water to obtain a methacrylated hyaluronic acid solution;

[0010] (2) dissolving N-isopropylacrylamide and N,N'-methylenebisacrylamide in deionized water at 60 degrees Celsius to obtain solution B, stirring the obtained solution B at 60 degrees Celsius and ultrasonically treating it, introducing nitrogen into the solution to obtain a transparent solution C, adding N,N,N',N'-tetramethylethylenediamine to the transparent solution C, and ultrasonically treating it to obtain a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide;

[0011] (3) adding the methacrylated hyaluronic acid solution obtained in step (1) dropwise to the monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide obtained in step (2), and mixing them thoroughly to obtain a mixed solution; then adding ammonium persulfate to the mixed solution, and transferring it to a double-layer insulating glass mold, constructing the smart hydrogel in a constant temperature water bath at a synthesis temperature of 10 to 32 degrees Celsius, and obtaining a double-layer insulating glass containing the smart hydrogel.

[0012] Furthermore, when the synthesis temperature in step (3) is 17 degrees Celsius, the average pore size of the smart hydrogel is 8 microns to 36 microns.

[0013] Furthermore, when the synthesis temperature in step (3) is 21 degrees Celsius, the average pore size of the smart hydrogel is 10 microns to 40 microns.

[0014] Furthermore, when the synthesis temperature in step (3) is 25 degrees Celsius, the average pore size of the smart hydrogel is 12 microns to 46 microns.

[0015] Furthermore, in step (1), in solution A, the concentration of methacrylic anhydride is 1-8 g / L, and the concentration of hyaluronic acid is 5-31 g / L; the concentration of the sodium hydroxide solution is 1 mol / L; and the mass percentage concentration of the obtained methacrylated hyaluronic acid solution is 2%-35%.

[0016] Furthermore, the PNIPAm / HAMA smart hydrogels were able to withstand water retention tests. After five hours in an environment with a temperature of 30 degrees Celsius and a relative humidity of 50%, the mass loss of the smart hydrogel containing 2% methacryloylated hyaluronic acid was 50%, that of the smart hydrogel containing 12% methacryloylated hyaluronic acid was 45%, and that of the smart hydrogel containing 22% methacryloylated hyaluronic acid was 38%. The mass loss of the hydrogel containing 12% methacryloylated hyaluronic acid after sealing was less than 1%.

[0017] Furthermore, in step (2), in solution B, the concentration of N-isopropylacrylamide is 140-370 g / L, and the concentration of N,N'-methylenebisacrylamide is 4.3-30 g / L; in solution C, the volume ratio of deionized water to N,N,N',N'-tetramethylethylenediamine is 1000:(16-79).

[0018] Furthermore, in step (3), the volume ratio of the methacrylated hyaluronic acid solution obtained in step (1) to the N,N'-methylenebisacrylamide monomer solution obtained in step (2) is 2% to 22%.

[0019] Furthermore, in step (3), the constant temperature water bath is a super constant temperature water bath.

[0020] Furthermore, step (1) specifically includes the following steps:

[0021] 0.1 g to 0.8 g of methacrylic anhydride and 0.5 g to 3.1 g of hyaluronic acid are dissolved in 100 ml of deionized water and cooled to 0 to 4 degrees Celsius to obtain solution A. A sodium hydroxide solution with a concentration of 1 mol / L is added dropwise to solution A to adjust the pH to 9 to 10. After the addition is completed, the resulting solution is stirred at 0 to 4 degrees Celsius and dialyzed against deionized water at 4 degrees Celsius. After dialysis, the solution is freeze-dried to obtain a solid of methacryloyl hyaluronic acid. The solid is dissolved in deionized water at a concentration of 1 mol / L to obtain a methacryloyl hyaluronic acid solution, named HAMA.

[0022] Furthermore, step (2) specifically includes the following steps:

[0023] 1.4 g to 3.7 g of N-isopropylacrylamide and 43 mg to 300 mg of N,N'-methylenebisacrylamide are dissolved in 10 ml of deionized water at 60 degrees Celsius to obtain solution B. The obtained solution B is stirred and ultrasonically treated at 60 degrees Celsius. Nitrogen gas is introduced into the solution to obtain a transparent solution C. 160 μL to 790 μL of N,N,N',N'-tetramethylethylenediamine is added to the transparent solution C, and the solution is ultrasonically treated to obtain a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide.

[0024] Furthermore, step (3) specifically includes the following steps:

[0025] The methacrylated hyaluronic acid solution with a mass percentage concentration of 2% to 35% obtained in step (1) is added dropwise to the monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide obtained in step (2), and the mixture is fully mixed to obtain a mixed solution; then, 1400 microliters of ammonium persulfate is added to the mixed solution, and the mixture is quickly transferred to a double-layer insulating glass mold, and the smart hydrogel is constructed in a super constant temperature water bath with a synthesis temperature of 10 to 32 degrees Celsius to obtain a double-layer insulating glass containing the smart hydrogel.

[0026] Furthermore, the PNIPAm / HAMA smart hydrogel exhibits precise phase transition temperature adjustability. While maintaining the same methacryloyl hyaluronic acid concentration, decreasing the synthesis temperature significantly lowers the phase transition temperature. Similarly, increasing the methacryloyl hyaluronic acid concentration while maintaining the same synthesis temperature also significantly lowers the phase transition temperature.

[0027] Furthermore, the PNIPAm / HAMA smart hydrogel has high light transmittance and high solar energy regulation efficiency. The double-layer insulating glass containing the smart hydrogel has a light transmittance of 91.1% to 98.5% in the visible light to near-infrared wavelength range of 380 nanometers to 2500 nanometers, a visible light modulation capacity of 74.5% to 80.9%, a solar light modulation capacity of 60.2% to 64.8%, and an infrared modulation capacity of 39.8% to 47.6%.

[0028] Furthermore, the PNIPAm / HAMA smart hydrogel was able to withstand optical stability testing. At a temperature of 35 degrees Celsius, the hydrogel's light transmittance remained stable, with no significant change after 50 measurement cycles.

[0029] The PNIPAm / HAMA smart hydrogel was able to withstand structural stability tests and showed no significant shrinkage in area after 500 cycles and after freezing at -5 degrees Celsius for 48 hours.

[0030] The second object of the present invention is to provide a smart hydrogel prepared by the method of constructing a smart hydrogel in a double-layer insulating glass.

[0031] Furthermore, the smart hydrogel is in double-layer insulating glass.

[0032] Furthermore, the smart hydrogel is a smart hydrogel with accurately adjustable phase transition temperature, high light transmittance, high solar energy regulation efficiency and good stability.

[0033] Furthermore, the smart hydrogel can be used to construct double-layer insulating glass containing the smart hydrogel for application as a smart window.

[0034] Compared with the prior art, the beneficial effects of the present invention are embodied in the following aspects:

[0035] The present invention first prepares a methacrylated hyaluronic acid solution and a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide, and then synthesizes the PNIPAm / HAMA smart hydrogel in a constant temperature water bath. The preparation method of the present invention is significantly simple and reduces manufacturing costs. The prepared PNIPAm / HAMA smart hydrogel has good optical properties and stability, temperature-dependent characteristics, and can accurately control the thermochromic temperature.

[0036] The present invention uses methacrylic anhydride, hyaluronic acid, and sodium hydroxide as raw materials to prepare a methacrylated hyaluronic acid solution. Then, N-isopropylacrylamide, N,N'-methylenebisacrylamide, and N,N,N',N'-tetramethylethylenediamine are used as raw materials to prepare a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide. PNIPAm / HAMA smart hydrogel with accurately adjustable phase transition temperature, high light transmittance, high solar energy regulation efficiency, and good stability is prepared in double-layer insulating glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Scanning electron micrograph of the PNIPAm / HAMA smart hydrogel prepared in Example 2 of the present invention at a synthesis temperature of 17 degrees Celsius and a mass percentage concentration of 2% of the methacrylated hyaluronic acid solution.

[0038] Figure 2Scanning electron micrograph of the PNIPAm / HAMA smart hydrogel prepared in Example 2 of the present invention at a synthesis temperature of 21 degrees Celsius and a mass percentage concentration of 12% of the methacryloyl hyaluronic acid solution.

[0039] Figure 3 Scanning electron micrograph of the PNIPAm / HAMA smart hydrogel prepared in Example 2 of the present invention at a synthesis temperature of 25 degrees Celsius and a mass percentage concentration of methacryloyl hyaluronic acid solution of 22%.

[0040] Figure 4 Differential scanning calorimetry graphs of the PNIPAm / HAMA smart hydrogels prepared in Example 3 of the present invention at a synthesis temperature of 17 degrees Celsius and with mass percentage concentrations of methacryloyl hyaluronic acid solutions of 2%, 12% and 22%, respectively.

[0041] Figure 5 Differential scanning calorimetry graphs of the PNIPAm / HAMA smart hydrogels prepared in Example 3 of the present invention at a synthesis temperature of 21 degrees Celsius and with mass percentage concentrations of methacryloyl hyaluronic acid solutions of 2%, 12% and 22%, respectively.

[0042] Figure 6 Differential scanning calorimetry graphs of the PNIPAm / HAMA smart hydrogels prepared in Example 3 of the present invention at a synthesis temperature of 25 degrees Celsius and with mass percentage concentrations of methacryloyl hyaluronic acid solutions of 2%, 12% and 22%, respectively.

[0043] Figure 7 The transmission spectra of the PNIPAm / HAMA smart hydrogels with thicknesses of 100 μm and 2000 μm prepared in Example 4 of the present invention are in the visible light to near-infrared wavelength region of 380 nm to 2500 nm.

[0044] Figure 8 In Example 2 of the present invention, the water retention performance of the prepared PNIPAm / HAMA smart hydrogel was tested. The mass change diagram of the PNIPAm / HAMA smart hydrogel before and after the water retention performance test is shown.

[0045] Figure 9 In Example 2 of the present invention, the optical performance stability test was performed on the prepared PNIPAm / HAMA smart hydrogel. The transmittance comparison chart of the PNIPAm / HAMA smart hydrogel before and after the optical performance stability test is shown (the mass percentage concentration of the methacryloyl hyaluronic acid solution is 12%).

[0046] Figure 10In Example 2 of the present invention, the prepared PNIPAm / HAMA smart hydrogel was subjected to a structural stability test. The volume change diagram of the PNIPAm / HAMA smart hydrogel before and after the structural stability test is shown (the mass percentage concentration of the methacryloyl hyaluronic acid solution is 12%). DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to specific embodiments, but is by no means intended to limit the present invention. Any features, such as preparation methods, materials, structures, or composition ratios, that are not explicitly described in this technical solution are considered to be common technical features disclosed in the prior art.

[0048] The following examples will help those skilled in the art further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that those skilled in the art may make several variations and improvements without departing from the scope of the present invention. These variations and improvements are all within the scope of protection of the present invention.

[0049] The practice of the present invention can employ conventional techniques of chemistry within the skill of the art. In the following examples, efforts have been made to ensure accuracy with respect to the numbers used (including amounts, temperatures, reaction times, etc.), but some experimental errors and deviations should be accounted for.

[0050] The present invention provides a method and smart hydrogel for constructing a double-layer insulating glass unit with a precisely adjustable phase transition temperature, high light transmittance, high solar energy control efficiency, and excellent stability. The method first prepares a methacrylated hyaluronic acid solution and a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide, adds N,N,N',N'-tetramethylethylenediamine, and uniformly disperses the mixture through ultrasonic treatment. The monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide is then thoroughly mixed with the methacrylated hyaluronic acid solution. Ammonium persulfate is added to the mixture, and the mixture is quickly transferred to a double-layer insulating glass mold. The smart hydrogel is then prepared in a super-constant temperature water bath. The preparation method is remarkably simple and reduces manufacturing costs. Double-layer insulating glass units containing the smart hydrogel achieve a maximum light transmittance of 98.5%, a visible light modulation capacity of 80.9%, a solar light modulation capacity of 64.8%, and an infrared modulation capacity of 47.6%. Its thermochromic temperature can be accurately controlled by adjusting the concentration of methacryloylated hyaluronic acid and the synthesis temperature. It also has excellent moisturizing properties and does not show obvious shrinkage after multiple cycles, showing excellent structural strength.

[0051] Example 1

[0052] This embodiment provides a method for constructing a smart hydrogel in a double-layer insulating glass (a method for preparing a PNIPAm / HAMA smart hydrogel), comprising the following steps:

[0053] (1) Preparation of methacryloylated hyaluronic acid solution: 0.75 g of methacrylic anhydride and 2 g of hyaluronic acid were dissolved in 100 ml of deionized water and cooled to 2 degrees Celsius; then, a sodium hydroxide solution (aqueous solution) with a concentration of 1 mol / L was added dropwise to the solution to adjust the pH to 9; after the addition was completed, the resulting solution was stirred at 0 to 4 degrees Celsius (generally, the stirring time was about 3 hours); the solution was dialyzed against deionized water (11000 Da) at 4 degrees Celsius, with the water changed every 8 hours for 8 days; after dialysis, the solution was freeze-dried at -60°C for 30 hours to obtain a white flocculent solid of methacryloylated hyaluronic acid; deionized water was used to dissolve the solid to obtain a methacryloylated hyaluronic acid solution, named HAMA, with a mass percentage concentration of 2% to 35% of methacryloylated hyaluronic acid solution;

[0054] (2) preparing a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide: dissolving 2 g of N-isopropylacrylamide and 200 mg of N,N'-methylenebisacrylamide in 10 ml of deionized water at 60 degrees Celsius, and then subjecting the resulting solution to magnetic stirring at 60 degrees Celsius (generally, the stirring time is about 30 minutes and the stirring rate is 400 rpm) and ultrasonic treatment (generally, the ultrasonic dispersion time is about 20 minutes); after the ultrasonic treatment, nitrogen is introduced into the solution to remove oxygen to obtain a transparent solution (generally, the nitrogen introduction time is about 15 minutes); 560 μl of N,N,N',N'-tetramethylethylenediamine is added to the resulting solution, and ultrasonic treatment is performed (generally, the ultrasonic dispersion time is about 20 minutes) to obtain a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide;

[0055] (3) Preparation of smart hydrogel: 1400 μL of the methacrylated hyaluronic acid solution with a mass percentage concentration of 2% to 35% obtained in step (1) was added dropwise to 10 ml of the monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide obtained in step (2), and the mixture was thoroughly mixed; then 1400 μL of ammonium persulfate with a concentration of 1 gram per liter was added to the mixed solution, and the mixture was quickly transferred to a double-layer hollow glass mold. The thickness of the double-layer hollow glass mold was set to 2000 μm, and the smart hydrogel was constructed in a super constant temperature water bath at a temperature of 17 degrees Celsius, named PNIPAm / HAMA smart hydrogel, to obtain a double-layer hollow glass containing the smart hydrogel.

[0056] When the mass percentage concentration of the methacryloyl hyaluronic acid solution added in step (3) is 2%, 12% and 22%, respectively, the average pore sizes of the prepared PNIPAm / HAMA smart hydrogels are 16 μm, 19 μm and 23 μm, respectively.

[0057] Example 2

[0058] This embodiment provides a method for constructing a smart hydrogel in a double-layer insulating glass (a method for preparing a PNIPAm / HAMA smart hydrogel), comprising the following steps:

[0059] (1) Preparation of methacryloylated hyaluronic acid solution: 0.75 g of methacrylic anhydride and 2 g of hyaluronic acid were dissolved in 100 ml of deionized water and cooled to 2 degrees Celsius; then, a sodium hydroxide solution (aqueous solution) with a concentration of 1 mol / L was added dropwise to the solution to adjust the pH to 9; after the addition was completed, the resulting solution was stirred at 0 to 4 degrees Celsius (generally, the stirring time was about 3 hours); the solution was dialyzed against deionized water (11000 Da) at 4 degrees Celsius, with the water changed every 8 hours for 8 days; after dialysis, the solution was freeze-dried at -60°C for 30 hours to obtain a white flocculent solid of methacryloylated hyaluronic acid; the solid was dissolved in deionized water to obtain a methacryloylated hyaluronic acid solution, named HAMA, with a mass percentage concentration of 12%;

[0060] (2) preparing a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide: dissolving 2 g of N-isopropylacrylamide and 200 mg of N,N'-methylenebisacrylamide in 10 ml of deionized water at 60 degrees Celsius, and then subjecting the resulting solution to magnetic stirring at 60 degrees Celsius (generally, the stirring time is about 30 minutes and the stirring rate is 400 rpm) and ultrasonic treatment (generally, the ultrasonic dispersion time is about 20 minutes); after the ultrasonic treatment, nitrogen is introduced into the solution to remove oxygen to obtain a transparent solution (generally, the nitrogen introduction time is about 15 minutes); 560 μl of N,N,N',N'-tetramethylethylenediamine is added to the resulting solution, and ultrasonic treatment is performed (generally, the ultrasonic dispersion time is about 20 minutes) to obtain a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide;

[0061] (3) Preparation of smart hydrogel: 1400 μL of the 12% by mass methacrylated hyaluronic acid solution obtained in step (1) was added dropwise to 10 mL of the monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide obtained in step (2), and the mixture was thoroughly mixed; then 1400 μL of ammonium persulfate with a concentration of 1 g / L was added dropwise to the mixed solution, and the mixture was quickly transferred to a double-layer hollow glass mold. The thickness of the double-layer hollow glass mold was set to 200 μm, and the smart hydrogel was constructed in a super constant temperature water bath at temperatures of 17 degrees Celsius, 21 degrees Celsius, and 25 degrees Celsius, respectively, and named PNIPAm / HAMA smart hydrogel to obtain a double-layer hollow glass containing the smart hydrogel.

[0062] When the hydrogel is prepared using a constant temperature water bath method at temperatures of 17 degrees Celsius, 21 degrees Celsius, and 25 degrees Celsius, the average pore sizes of the prepared PNIPAm / HAMA smart hydrogel are 2.1 nanometers, 1.7 nanometers, and 1.1 nanometers, respectively. Figure 1 、 Figure 2 and Figure 3 The scanning electron microscope images of the hydrogels prepared at constant temperature water bath temperatures of 17 degrees Celsius, 21 degrees Celsius and 25 degrees Celsius respectively.

[0063] The water retention performance of the PNIPAm / HAMA smart hydrogel prepared in Example 2 was tested. Figure 8 As shown, a double-layer insulating glass containing smart hydrogel was sealed using a waterproof and moisture-proof tape. After 5 hours in an environment with a temperature and relative humidity of 30 degrees Celsius and 50%, respectively, the mass loss of the hydrogel containing different concentrations of methacryloylated hyaluronic acid solution was less than 50%, which was lower than the pure PNIPAm hydrogel in the comparative example. The mass loss of the hydrogel containing 12% methacryloylated hyaluronic acid after sealing was less than 1%, which was much lower than the pure PNIPAm hydrogel in the comparative example. That is, the water retention effect of the hydrogel containing different concentrations of methacryloylated hyaluronic acid solution was better than that of the pure PNIPAm hydrogel in the comparative example. The water retention effect of the hydrogel containing 12% methacryloylated hyaluronic acid after sealing was much better than that of the pure PNIPAm hydrogel in the comparative example, proving that the PNIPAm / HAMA smart hydrogel passed the water retention performance test and had good stability.

[0064] The optical stability test of the PNIPAm / HAMA smart hydrogel prepared in Example 2 was carried out. Figure 9As shown in the figure, at a temperature of 35 degrees Celsius, the transmittance of the hydrogel with a synthesis temperature of 25 degrees Celsius remains stable. Taking heating from low temperature (20 degrees Celsius) to high temperature (35 degrees Celsius) as a measurement cycle, the hydrogel has no obvious change after 50 measurement cycles, proving that the PNIPAm / HAMA smart hydrogel has passed the optical performance stability test and has good stability.

[0065] The structural stability test of the PNIPAm / HAMA smart hydrogel prepared in Example 2 was carried out. Figure 10 As shown, with heating from low temperature (20 degrees Celsius) to high temperature (35 degrees Celsius) as one cycle, after 500 cycles and after freezing at a temperature of -5 degrees Celsius for 144 hours, the area of ​​the hydrogel of Example (2) with a synthesis temperature of 25 degrees Celsius did not show obvious shrinkage, proving that the PNIPAm / HAMA smart hydrogel passed the structural stability test and had good stability.

[0066] Example 3

[0067] This embodiment provides a method for constructing a smart hydrogel in a double-layer insulating glass (a method for preparing a PNIPAm / HAMA smart hydrogel), which is basically the same as the preparation method in Example 2. The method for preparing the PNIPAm / HAMA smart hydrogel using a constant temperature water bath method is the same as that in Example 2, except that: in step (3), the concentration of the methacryloylated hyaluronic acid solution and the temperature of the constant temperature water bath are simultaneously controlled to obtain PNIPAm / HAMA smart hydrogels with mass percentage concentrations of 2%, 12% and 22% of the methacryloylated hyaluronic acid solution at synthesis temperatures of 17 degrees Celsius, 21 degrees Celsius and 25 degrees Celsius, respectively.

[0068] Figure 4 、 Figure 5 and Figure 6 The differential scanning calorimetry diagrams of PNIPAm / HAMA smart hydrogels with mass percentage concentrations of methacryloyl hyaluronic acid solutions of 2%, 12% and 22% at synthesis temperatures of 17 degrees Celsius, 21 degrees Celsius and 25 degrees Celsius, respectively, show that when the concentration of methacryloyl hyaluronic acid remains unchanged, the peak temperature of the exothermic peak decreases as the synthesis temperature decreases, proving that when the concentration of methacryloyl hyaluronic acid remains unchanged, the decrease in synthesis temperature will significantly decrease the phase transition temperature of the smart hydrogel; when the concentration of methacryloyl hyaluronic acid increases when the synthesis temperature remains unchanged, the peak temperature of the exothermic peak decreases. When the synthesis temperature remains unchanged, the increase in the concentration of methacryloyl hyaluronic acid will also significantly decrease the phase transition temperature of the smart hydrogel.

[0069] Example 4

[0070] This embodiment provides a method for constructing a smart hydrogel in a double-layer insulating glass (a method for preparing a PNIPAm / HAMA smart hydrogel), which is basically the same as the preparation method in Example 2. The method for preparing the PNIPAm / HAMA smart hydrogel using a constant temperature water bath method is the same as that in Example 2, except that: in step (3), the smart hydrogel is constructed in a super constant temperature water bath at a temperature of 17 degrees Celsius. In step (3), the thickness of the double-layer insulating glass mold is set to 100 microns and 2000 microns, respectively, and PNIPAm / HAMA smart hydrogels with accurately adjustable phase change temperature, high light transmittance, high solar energy regulation efficiency and good stability are constructed in the double-layer insulating glass mold.

[0071] The transmission spectra of PNIPAm / HAMA smart hydrogels with thicknesses of 100 μm and 2000 μm in the visible to near-infrared wavelength region from 380 nm to 2500 nm are as follows: Figure 7As shown, when the spectrum is measured at a temperature of 20 degrees Celsius, under the conditions of a synthetic temperature of 17 degrees Celsius and a thickness of 100 microns, the transmittance reaches 98.5% when the wavelength is 300-780nm. Under the conditions of a synthetic temperature of 17 degrees Celsius and a thickness of 100 microns, the sunlight modulation ability reaches 53.6% when the wavelength is 200-2500nm. Under the conditions of a synthetic temperature of 17 degrees Celsius and a thickness of 100 microns, the infrared modulation ability reaches 10.6% when the wavelength is 1100-2500nm. Under the conditions of synthesis temperature of 17 degrees Celsius and thickness of 2000 microns, the visible light modulation capability reached 80.9% at a wavelength of 200-780nm. Under the conditions of synthesis temperature of 17 degrees Celsius and thickness of 2000 microns, the sunlight modulation capability reached 64.8% at a wavelength of 200-2500nm. Under the conditions of synthesis temperature of 17 degrees Celsius and thickness of 2000 microns, the infrared modulation capability reached 49.5% at a wavelength of 1100-2500nm. %; when the temperature is 40 degrees Celsius, the spectrum is measured. Under the conditions of synthetic temperature of 17 degrees Celsius and thickness of 100 microns, the transmittance reaches 94.3% when the wavelength is 300-780nm. Under the conditions of synthetic temperature of 17 degrees Celsius and thickness of 100 microns, the sunlight modulation ability reaches 56.8% when the wavelength is 200-2500nm. Under the conditions of synthetic temperature of 17 degrees Celsius and thickness of 100 microns, the infrared modulation ability reaches 32 0.8%. Under the conditions of synthesis temperature of 17 degrees Celsius and thickness of 2000 microns, the visible light modulation capability reached 62.2% at wavelengths of 200-780nm. Under the conditions of synthesis temperature of 17 degrees Celsius and thickness of 2000 microns, the solar light modulation capability reached 60.6% at wavelengths of 200-2500nm. Under the conditions of synthesis temperature of 17 degrees Celsius and thickness of 2000 microns, the infrared light modulation capability reached 32.7% at wavelengths of 1100-2500nm. By comparison, thickness has a significant impact on solar light modulation capability and infrared modulation capability. Spectral test temperature (and ambient temperature) has a significant impact on visible light transmittance and visible light modulation capability.

[0072] Comparative Example

[0073] This comparative example provides a method for constructing a PNIPAm hydrogel in a double-layer insulating glass, comprising the following steps:

[0074] (1) preparing a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide: dissolving 2 g of N-isopropylacrylamide and 200 mg of N,N'-methylenebisacrylamide in 10 ml of deionized water at 60 degrees Celsius, and then subjecting the resulting solution to magnetic stirring at 60 degrees Celsius (generally, the stirring time is about 30 minutes and the stirring rate is 400 rpm) and ultrasonic treatment (generally, the ultrasonic dispersion time is about 20 minutes); after the ultrasonic treatment, nitrogen gas is introduced into the solution to remove oxygen to obtain a transparent solution (generally, the nitrogen introduction time is about 15 minutes); adding 560 μl of N,N,N',N'-tetramethylethylenediamine to the resulting solution, and ultrasonic treatment is performed (generally, the ultrasonic dispersion time is about 20 minutes) to obtain a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide;

[0075] (2) Preparation of PNIPAm hydrogel: 10 ml of the monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide obtained in step (2) was taken, 1400 μL of ammonium persulfate with a concentration of 1 g / L was added thereto, and the solution was quickly transferred to a double-layer insulating glass mold. The thickness of the double-layer insulating glass mold was set to 200 μm. The smart hydrogel, named PNIPAm hydrogel, was constructed in a super constant temperature water bath at temperatures of 17 degrees Celsius, 21 degrees Celsius, and 25 degrees Celsius, respectively, to obtain a double-layer insulating glass containing PNIPAm hydrogel.

[0076] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned embodiments. The description of the embodiments is for the convenience of ordinary technicians in this technical field to understand and use the invention. It is obvious that those familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to go through creative work. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for constructing smart hydrogel in double-layer insulating glass, characterized in that: The method comprises the following steps: (1) dissolving methacrylic anhydride and hyaluronic acid in deionized water, cooling the solution to 0-4 degrees Celsius to obtain solution A, and adding sodium hydroxide solution dropwise to solution A to adjust the pH to 9-10; after the addition is completed, stirring the resulting solution at 0-4 degrees Celsius, dialyzing the solution with deionized water at 4 degrees Celsius, and freeze-drying the solution after dialysis to obtain a solid of methacryloyl hyaluronic acid; and dissolving the solid in deionized water to obtain a methacryloyl hyaluronic acid solution; (2) dissolving N-isopropylacrylamide and N,N'-methylenebisacrylamide in deionized water at 60 degrees Celsius to obtain solution B, stirring the obtained solution B at 60 degrees Celsius and ultrasonically treating it, introducing nitrogen into the solution to obtain a transparent solution C, adding N,N,N',N'-tetramethylethylenediamine to the transparent solution C, and ultrasonically treating it to obtain a monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide; (3) adding the methacrylated hyaluronic acid solution obtained in step (1) dropwise to the monomer solution containing N-isopropylacrylamide and N,N'-methylenebisacrylamide obtained in step (2), and mixing thoroughly to obtain a mixed solution; then adding ammonium persulfate to the mixed solution, and transferring the mixed solution to a double-layer insulating glass mold, constructing the smart hydrogel in a constant temperature water bath at a synthesis temperature of 17 to 32 degrees Celsius, and obtaining a double-layer insulating glass containing the smart hydrogel; In step (1), the mass percentage concentration of the obtained methacryloyl hyaluronic acid solution is 2% to 35%; In step (2), in solution B, the concentration of N-isopropylacrylamide is 140-370 g / L, and the concentration of N,N'-methylenebisacrylamide is 4.3-30 g / L; In step (3), the volume ratio of the methacrylated hyaluronic acid solution obtained in step (1) to the monomer solution obtained in step (2) is 2% to 22%.

2. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: When the synthesis temperature in step (3) is 17 degrees Celsius, the average pore size of the smart hydrogel is 8 microns to 36 microns.

3. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: When the synthesis temperature in step (3) is 21 degrees Celsius, the average pore size of the smart hydrogel is 10 microns to 40 microns.

4. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: When the synthesis temperature in step (3) is 25 degrees Celsius, the average pore size of the smart hydrogel is 12 microns to 46 microns.

5. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: In step (1), in solution A, the concentration of methacrylic anhydride is 1-8 g / L, and the concentration of hyaluronic acid is 5-31 g / L; The concentration of the sodium hydroxide solution is 1 mol / L.

6. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: After 5 hours in an environment with a temperature and relative humidity of 30 degrees Celsius and 50%, respectively, the mass loss of the smart hydrogel containing 2% methacryloyl hyaluronic acid was 50%, the mass loss of the smart hydrogel containing 12% methacryloyl hyaluronic acid was 45%, and the mass loss of the smart hydrogel containing 22% methacryloyl hyaluronic acid was 38%. The mass loss of the hydrogel containing 12% methacryloyl hyaluronic acid after sealing was less than 1%.

7. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: In the solution C, the volume ratio of deionized water to N,N,N',N'-tetramethylethylenediamine is 1000:(16-79).

8. The method for constructing smart hydrogel in double-layer insulating glass according to claim 1, characterized in that: The double-layer insulating glass containing smart hydrogel has a light transmittance of 91.1% to 98.5% in the visible light to near-infrared wavelength range of 380 nanometers to 2500 nanometers, a visible light modulation capacity of 74.5% to 80.9%, a solar light modulation capacity of 60.2% to 64.8%, and an infrared light modulation capacity of 39.8% to 47.6%. The light transmittance of the smart hydrogel remained stable at a temperature of 35 degrees Celsius, with no significant change after 50 measurement cycles. After 500 cycles and after being frozen at -5 degrees Celsius for 48 hours, the area of ​​the smart hydrogel did not show obvious shrinkage.

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