Block copolymer, thermoresponsive light modulating device, preparation method and application thereof

Abstract

The present invention discloses a block copolymer, a thermoresponsive dimming device, and a preparation method and application thereof. The block copolymer is obtained by copolymerizing a nonionic polymer with a high critical solution temperature and a nonionic polymer with a low critical solution temperature; wherein, the thermoresponsive temperature value of the nonionic polymer with a high critical solution temperature is less than the thermoresponsive temperature value of the nonionic polymer with a low critical solution temperature. It can ensure that the block copolymer is opaque both below the high critical solution temperature and above the low critical solution temperature, and is only transparent and visible within the environmental temperature range above the high critical solution temperature and below the low critical solution temperature. In this way, it is convenient to keep warm and reduce heat dissipation during indoor heating at low temperatures, and prevent outdoor heat radiation from passing through and reduce heating at high temperatures. It can be used in smart windows.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a block copolymer, a thermoresponsive light modulating device, and a preparation method and application thereof. Background Art

[0002] A smart window is an optical device that can adaptively change its own optical properties such as light transmittance and color according to changes in external conditions, and can further adjust the indoor lighting and temperature according to changes in external conditions. Smart windows can be classified into three categories according to their adjustment mechanisms: thermochromic smart windows, electro-responsive smart windows, and electrochromic smart windows. Among them, electro-responsive smart windows have defects such as long electro-responsive time and high driving voltage, resulting in large energy losses, and the conversion of electrical energy to heat energy makes it difficult to control the indoor temperature. Electrochromic smart windows usually use electrochromic materials such as metal compounds, which not only increase the manufacturing cost, but also easily cause environmental hazards such as metal pollution, high energy consumption, and difficult recycling. In contrast, thermochromic smart windows are an ideal choice for the new generation of smart windows due to their low material cost, fast response rate, and no energy consumption. However, the current thermoresponsive smart windows generally have a limited adjustable range of response temperature values, and it is even more impossible to set a suitable temperature range, resulting in limited practical applications. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, a first aspect of the present invention provides a block copolymer.

[0004] A second aspect of the present invention further provides a thermoresponsive light modulating device.

[0005] A third aspect of the present invention further provides a preparation method of a thermoresponsive light modulating device.

[0006] A fourth aspect of the present invention further provides an application of a thermoresponsive light modulating device.

[0007] According to an embodiment of the first aspect of the present invention, a block copolymer is provided, which is obtained by copolymerizing a nonionic polymer with a high critical solution temperature and a nonionic polymer with a low critical solution temperature;

[0008] Wherein, the thermoresponsive temperature value of the nonionic polymer with a high critical solution temperature is less than the thermoresponsive temperature value of the nonionic polymer with a low critical solution temperature.

[0009] The block copolymer according to the embodiment of the present invention has at least the following beneficial effects:

[0010] The present invention selects non-ionic high molecular polymers and avoids using ionic high molecular polymers because if ionic high molecular polymers are used, they are liable to be affected by the types, concentrations and distributions of environmental ions in addition to the environmental temperature and cannot be precisely regulated.

[0011] On the other hand, by limiting the thermal response temperature value of the non-ionic high molecular polymer with a high critical solution temperature to be less than that of the non-ionic high molecular polymer with a low critical solution temperature, it can be ensured that the block copolymer is opaque both below the high critical solution temperature and above the low critical solution temperature, and is only transparent and visible within the environmental temperature range above the high critical solution temperature and below the low critical solution temperature. In this way, it is convenient to keep warm and reduce heat dissipation during indoor heating at low temperatures, and prevent outdoor heat radiation from passing through and reduce heating at high temperatures.

[0012] It should be noted that the thermal response temperature value is the corresponding temperature value when the visible light transmittance of the non-ionic high molecular polymer solution or gel reaches 50% during heating.

[0013] The "lower critical solution temperature" refers to the lowest point of the phase separation curve in the temperature-concentration diagram.

[0014] The "upper critical solution temperature" refers to the highest point of the phase separation curve in the temperature-concentration diagram.

[0015] According to some embodiments of the present invention, the mass ratio of the non-ionic high molecular polymer with a high critical solution temperature to the non-ionic high molecular polymer with a low critical solution temperature is 1:(1-2).

[0016] According to some embodiments of the present invention, the thermal response temperature value of the non-ionic high molecular polymer with a high critical solution temperature is 10°C to 30°C. Thus, the temperature can be regulated to the most suitable indoor temperature range.

[0017] According to some embodiments of the present invention, the non-ionic high molecular polymer with a high critical solution temperature is selected from at least one or more of poly(acrylonitrile-co-acrylamide) random copolymer, polyacrylic acid uracil ester, poly-N-acryloylglycinamidine, poly-N-acryloylasparagine, poly-N-acryloylglutamine, polymethacryloylasparagine, poly(butyl acrylate-co-N-acrylamidoglycinamide) or poly(styrene-co-N-acrylamidoglycinamide).

[0018] According to some embodiments of the present invention, the non-ionic high molecular polymer with a low critical solution temperature is selected from at least one or more of poly(N-isopropylacrylamide) homopolymer, poly-N,N-diethylacrylamide, polymethyl vinyl ether, poly-N-vinylcaprolactam.

[0019] According to some embodiments of the present invention, the molar ratio of acrylonitrile monomer to acrylamide monomer in the poly(acrylonitrile-co-acrylamide) random copolymer is 1:1 to 3.

[0020] The present invention regulates the response temperature value and the response temperature range by controlling the molar ratio of acrylonitrile monomer to acrylamide monomer in the poly(acrylonitrile-co-acrylamide) random copolymer. Further, when the molar ratio of acrylonitrile monomer to acrylamide monomer is 1:1 to 3, the thermal response temperature range is better.

[0021] According to some embodiments of the present invention, the block copolymer is prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization reaction.

[0022] According to some embodiments of the present invention, the organic solvent used in the RAFT polymerization is N,N-dimethylformamide (DMF).

[0023] According to some embodiments of the present invention, the temperature of the RAFT polymerization is 50°C to 80°C.

[0024] An embodiment of the second aspect of the present invention provides a thermoresponsive light modulating device, including a first light-transmitting substrate and a second light-transmitting substrate arranged oppositely, a light modulating area is encapsulated between the first light-transmitting substrate and the second light-transmitting substrate, and the light modulating area includes the above-mentioned block copolymer and a polar solvent.

[0025] The thermoresponsive light modulating device according to the embodiment of the present invention has at least the following beneficial effects:

[0026] Selecting the block copolymer of the present invention can precisely regulate the response temperature value and the response temperature range, and then effectively realize the precise regulation of the response temperature of the thermoresponsive light modulating device. This thermoresponsive light modulating device does not require additional energy supply and regulation, and completely relies on the thermoresponsiveness of the block copolymer itself to change the visible light transmittance of its solution or gel, and has significant advantages such as good responsiveness, recoverability, stability and low energy consumption.

[0027] According to some embodiments of the present invention, the concentration of the block copolymer is ≥1 mg / mL.

[0028] According to some embodiments of the present invention, the first light-transmitting substrate and the second light-transmitting substrate independently include at least one of plexiglass, glass, silicon wafer or polyethylene terephthalate.

[0029] According to some embodiments of the present invention, the distance between the first light-transmitting substrate and the second light-transmitting substrate is 1 mm to 2 mm.

[0030] The third aspect of the present invention provides a method for preparing a thermoresponsive dimming device, comprising the following steps:

[0031] S1. Curing and encapsulating a first light-transmitting substrate and a second light-transmitting substrate to form a dimming area;

[0032] S2. Filling a block copolymer and a polar solvent into the dimming area under negative pressure to obtain the thermoresponsive dimming device.

[0033] The fourth aspect of the present invention provides the application of the above-mentioned dimming device in an intelligent window.

[0034] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. Description of the Drawings

[0035] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0036] Figure 1 is an infrared spectrogram, where Figure 1 a is the infrared spectrogram of the polymer P(AN-co-AM) prepared in Example 3, Figure 1 b is the infrared spectrogram of the block copolymer P(AN-co-AM)-b-PNIPAM prepared in Example 5;

[0037] Figure 2 is a graph showing the change of light transmittance of the polymer P(AN-co-AM) prepared in Example 1 with temperature in an aqueous solution;

[0038] Figure 3 is a graph showing the change of light transmittance of the polymer P(AN-co-AM) prepared in Example 2 with temperature in an aqueous solution;

[0039] Figure 4 is a graph showing the change of light transmittance of the polymer P(AN-co-AM) prepared in Example 3 with temperature in an aqueous solution;

[0040] Figure 5 is a graph showing the change of light transmittance of the block copolymer P(AN-co-AM)-b-PNIPAM prepared in Example 4 with temperature in an aqueous solution;

[0041] Figure 6 is a graph showing the change of light transmittance of the block copolymer P(AN-co-AM)-b-PNIPAM prepared in Example 5 with temperature in an aqueous solution;

[0042] Figure 7Graph of the light transmittance of the block copolymer P(AN-co-AM)-b-PNIPAM prepared in Example 6 varying with temperature in an aqueous solution;

[0043] Figure 8 Dimming diagram of the block copolymer in Example 6 at different temperatures.

[0044] Figure 9 Structural diagram of a thermally adaptive dimming device;

[0045] Reference numerals: first light-transmitting substrate 10, second light-transmitting substrate 11, sealing rubber ring 22, solution or gel injection port 33. Detailed implementation manners

[0046] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in combination with the embodiments, but the present invention is not limited to these embodiments.

[0047] The reagents, methods, and equipment used in the present invention are all conventional reagents, methods, and equipment in the technical field, unless otherwise specified.

[0048] Example 1

[0049] Example 1 provides a poly(acrylonitrile-co-acrylamide) random copolymer, and its preparation method is as follows:

[0050] Dissolve 1.48 g of acrylonitrile (AN), 4.47 g of acrylamide (AM), 0.04 g of 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate (chain transfer agent), and 4.9 mg of azobisisobutyronitrile (initiator) in 12.3 mL of DMF organic solvent. Perform 6 freeze-thaw-vacuum pumping cycles on the solution to remove the water and oxygen contained in the solution. React for 6 hours under a nitrogen atmosphere at a reaction temperature of 70°C. Precipitate the solution obtained after the reaction in methanol, and yellow solids will precipitate out in the solution. Centrifuge (filter) the above methanol solution and the solids to obtain a light yellow powder-like solid. Dialyze the obtained solid in a dialysis bag for three days. The dialysis bag used has a molecular weight cut-off of 500 to remove unreacted monomers and small molecular weight products, and change the deionized water every 6 hours during this period. Freeze-dry the solution in the dialysis bag to obtain a solid powder.

[0051] Example 2

[0052] Example 2 provides a poly(acrylonitrile-co-acrylamide) random copolymer, and its preparation method is as follows:

[0053] Dissolve 1.48 g of acrylonitrile (AN), 4.47 g of acrylamide (AM), 0.04 g of 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate (chain transfer agent), and 4.9 mg of azobisisobutyronitrile (initiator) in 15 mL of DMF organic solvent. Perform 6 freeze-thaw-vacuum cycles on the solution to remove the water and oxygen contained in the solution. React for 6 hours under a nitrogen atmosphere at a reaction temperature of 70 °C. Precipitate the solution obtained after the reaction in methanol, and yellow solids will precipitate out of the solution. Centrifuge (filter) the above methanol solution and the solids to obtain a light yellow powder-like solid. Dialyze the obtained solid in a dialysis bag for three days. The dialysis bag used has a molecular weight cut-off of 3500 to remove unreacted monomers and small molecular weight products, and change the deionized water every 6 hours during this period. Freeze-dry the solution in the dialysis bag to obtain a solid powder.

[0054] Example 3

[0055] Example 3 provides a poly(acrylonitrile-co-acrylamide) random copolymer, and its preparation method is as follows:

[0056] Dissolve 1.48 g of acrylonitrile (AN), 4.47 g of acrylamide (AM), 0.04 g of 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate (chain transfer agent), and 18.6 mg of azobisisobutyronitrile (initiator) in 15 mL of DMF organic solvent. Perform 6 freeze-thaw-vacuum cycles on the solution to remove the water and oxygen contained in the solution. React for 20 hours under a nitrogen atmosphere at a reaction temperature of 65 °C. Precipitate the solution obtained after the reaction in methanol, and yellow solids will precipitate out of the solution. Centrifuge (filter) the above methanol solution and the solids to obtain a light yellow powder-like solid. Dialyze the obtained solid in a dialysis bag for three days. The dialysis bag used has a molecular weight cut-off of 3500 to remove unreacted monomers and small molecular weight products, and change the deionized water every 6 hours during this period. Freeze-dry the solution in the dialysis bag to obtain a solid powder.

[0057] Example 4

[0058] Example 4 provides a block copolymer, and its preparation method is as follows:

[0059] Dissolve 0.15 g of P(AN-co-AM) from Example 2, 0.3 g of N-isopropylacrylamide (NIPAM), and 18 mg of azobisisobutyronitrile (initiator) in 15 mL of DMF. Perform 6 freeze-thaw-vacuum cycles on the solution to remove the water and oxygen contained in the solution. React for 6 hours under a nitrogen atmosphere at a reaction temperature of 70 °C. Precipitate the solution obtained after the reaction in ether, and yellow solids will precipitate out of the solution. Centrifuge (filter) the above ether solution and the solids to obtain a pale yellow powdery solid. Dialyze the obtained solid in a dialysis bag for three days. The dialysis bag used has a molecular weight cut-off of 3500 to remove unreacted monomers and small molecular weight products, and deionized water is changed every 6 hours during this period. Freeze-dry the solution in the dialysis bag to obtain the block copolymer P(AN-co-AM)-b-PNIPAM.

[0060] Example 5

[0061] Example 5 provides a block copolymer, and its preparation method is as follows:

[0062] Dissolve 0.25 g of P(AN-co-AM) from Example 3, 0.25 g of N-isopropylacrylamide (NIPAM), and 12 mg of azobisisobutyronitrile (initiator) in 15 mL of DMF. Perform 6 freeze-thaw-vacuum cycles on the solution to remove the water and oxygen contained in the solution. React for 6 hours under a nitrogen atmosphere at a reaction temperature of 70 °C. Precipitate the solution obtained after the reaction in ether, and yellow solids will precipitate out of the solution. Centrifuge (filter) the above ether solution and the solids to obtain a pale yellow powdery solid. Dialyze the obtained solid in a dialysis bag for three days. The dialysis bag used has a molecular weight cut-off of 3500 to remove unreacted monomers and small molecular weight products, and deionized water is changed every 6 hours during this period. Freeze-dry the solution in the dialysis bag to obtain the block copolymer P(AN-co-AM)-b-PNIPAM.

[0063] Figure 1 a is the infrared spectrum of the polymer P(AN-co-AM) prepared in Example 3, Figure 1 b is the infrared spectrum of the block copolymer P(AN-co-AM)-b-PNIPAM prepared in Example 5. Among them, the copolymer P(AN-co-AM)-b-PNIPAM is at wavenumbers 2242 cm -1 、1671 cm -1 、1314 cm -1 、1114 cm -1 and 3198 - 3609 cm -1 at and Figure 1The random copolymer P(AN-co-AM) in a has the same absorption peaks, indicating the presence of P(AN-co-AM) chain segments. At the same time, the copolymer P(AN-co-AM)-b-PNIPAM also shows weak absorption peaks at wavenumbers of 2968 cm -1 and 1172 cm -1 due to the stretching vibration of methyl C-H and the stretching vibration of the carbon-carbon backbone in CH(CH3)2, which originate from the repeating structural units of the PNIPAM chain segment. This proves the successful synthesis of the block copolymer P(AN-co-AM)-b-PNIPAM.

[0064] Example 6

[0065] Example 6 provides a block copolymer, and its preparation method is as follows:

[0066] Dissolve 0.25 g of P(AN-co-AM) from Example 3, 0.5 g of N-isopropylacrylamide (NIPAM), and 18 mg of azobisisobutyronitrile (initiator) in 15 mL of DMF. Perform 6 freeze-thaw-vacuum cycles on the solution to remove the water and oxygen contained in the solution. React for 6 hours under a nitrogen atmosphere at a reaction temperature of 70 °C. Precipitate the resulting solution in ether, and yellow solids will precipitate out of the solution. Centrifuge (filter) the above ether solution and the solids to obtain a pale yellow powder-like solid. Dialyze the obtained solid in a dialysis bag for three days. The dialysis bag used has a molecular weight cut-off of 3500 to remove unreacted monomers and small molecular weight products, and change the deionized water every 6 hours during this period. Freeze-dry the solution in the dialysis bag to obtain the block copolymer P(AN-co-AM)-b-PNIPAM.

[0067] Performance Test

[0068] Effect Example 1

[0069] Measure the change in the light transmittance of the solution at different temperatures using a UV spectrophotometer. Prepare a 1 mg / mL polymer P(AN-co-AM) solution from Example 1 and record the change in the transmittance of light passing through the solution with temperature.

[0070] Record the relationship between the transmittance and temperature using a UV spectrophotometer model UV-1750. Define the temperature corresponding to a transmittance of 50% as the cloud point of the thermoresponsive polymer, that is, the thermoresponsive temperature value. Place the above-prepared solution in the equipment, use a wavelength of 500 nm, and use a constant temperature water bath model CBC 5basic as the heating source for heating with a temperature gradient of 2 °C. Wait until the transmittance no longer changes and then adjust the temperature. The test results are as Figure 2 shown. The thermoresponsive temperature range is 15 - 25 °C, and the cloud point is 20.6 °C.

[0071] Effect Example 2

[0072] Prepare a 1 mg / mL solution of polymer P(AN-co-AM) in Example 2, and record the change in the light transmittance of the solution with temperature.

[0073] Record the relationship between the light transmittance and temperature through a UV-1750 ultraviolet spectrophotometer. Define the temperature corresponding to a light transmittance of 50% as the cloud point of the thermoresponsive polymer. Place the above-prepared solution in the equipment, use a wavelength of 500 nm, and heat it with a CBC 5basic constant temperature water bath as the heat source. The temperature gradient is 2 °C. Wait until the light transmittance no longer changes before adjusting the temperature. The test results are as Figure 3 shown. The thermoresponsive temperature range is 15 - 25 °C, and the cloud point is 20.6 °C. It can be seen from the figure that in the range of 7.5 °C - 17.5 °C, the change in light transmittance is close to 100%, and the temperature corresponding to a light transmittance of 50% is 14.0 °C.

[0074] Effect Example 3

[0075] Prepare a 1 mg / mL solution of polymer P(AN-co-AM) in Example 3, and record the change in the light transmittance of the solution with temperature.

[0076] Record the relationship between the light transmittance and temperature through a UV-1750 ultraviolet spectrophotometer. Define the temperature corresponding to a light transmittance of 50% as the cloud point of the thermoresponsive polymer. Place the above-prepared solution in the equipment, use a wavelength of 500 nm, and heat it with a CBC 5basic constant temperature water bath as the heat source. The temperature gradient is 2 °C. Wait until the light transmittance no longer changes before adjusting the temperature. From Figure 4 it can be seen that the thermoresponsive temperature range of polymer P(AN-co-AM) is 23 - 33 °C, and the thermoresponsive temperature corresponding to a light transmittance of 50% is 27.3 °C.

[0077] Effect Example 4

[0078] Prepare a 1 mg / mL solution of polymer P(AN-co-AM)-b-PNIPAM in Example 4, and record the change in the light transmittance of the solution with temperature.

[0079] Record the relationship between the light transmittance and temperature through a UV-1750 ultraviolet spectrophotometer. Define the temperature corresponding to a light transmittance of 50% as the cloud point of the thermoresponsive polymer. Place the above-prepared solution in the equipment, use a wavelength of 500 nm, and heat it with a CBC 5basic constant temperature water bath as the heat source. The temperature gradient is 2 °C. Wait until the light transmittance no longer changes before adjusting the temperature. The test results are as Figure 5As shown, the UCST point of the copolymer P(AN-co-AM) shifted from the initial 14 °C to 16.7 °C. This is due to the embedding of poly(N-isopropylacrylamide) (PNIPAM) in the molecular chain segments, resulting from the mutual influence within and between molecules. When the temperature is higher than 34.8 °C, the solubility of the copolymer P(AN-co-AM)-b-PNIPAM decreases, exhibiting LCST behavior, and the cloud point of the LCST segment is 42.6 °C.

[0080] Effect Example 5

[0081] Prepare a 1 mg / mL polymer P(AN-co-AM)-b-PNIPAM solution of Example 5, and record the change in the light transmittance through the solution with temperature.

[0082] Record the relationship between the light transmittance and temperature through a UV-1750 ultraviolet spectrophotometer. Define the temperature corresponding to a light transmittance of 50% as the cloud point of the thermoresponsive polymer. Place the above-prepared solution in the equipment, use a wavelength of 500 nm, and use a CBC 5basic constant temperature water bath as the heating source for heating with a temperature gradient of 2 °C. Adjust the temperature after waiting for the light transmittance to stop changing. The test results are as Figure 6 As shown, the UCST point of the copolymer P(AN-co-AM) shifted from the initial 27.3 °C to 18 °C. This is due to the embedding of poly(N-isopropylacrylamide) (PNIPAM) in the molecular chain segments, resulting from the mutual influence within and between molecules. When the temperature is higher than 34.8 °C, the solubility of the copolymer P(AN-co-AM)-b-PNIPAM decreases, exhibiting LCST behavior, but the LCST phenomenon is not obvious. This may be because in the block copolymer, the conversion rate of NIPAM is small and the molecular weight is small, resulting in the LCST behavior of poly(N-isopropylacrylamide) (PNIPAM) not being obvious.

[0083] Effect Example 6

[0084] Prepare a 1 mg / mL polymer P(AN-co-AM)-b-PNIPAM solution of Example 6, and record the change in the light transmittance through the solution with temperature.

[0085] Record the relationship between the light transmittance and temperature through a UV-1750 ultraviolet spectrophotometer. Define the temperature corresponding to a light transmittance of 50% as the cloud point of the thermoresponsive polymer. Place the above-prepared solution in the equipment, use a wavelength of 500 nm, and use a CBC 5basic constant temperature water bath as the heating source for heating with a temperature gradient of 2 °C. Adjust the temperature after waiting for the light transmittance to stop changing. The test results are as Figure 7 As shown, the UCST and LCST cloud points corresponding to the polymer are 23.7 °C and 42 °C, respectively.

[0086] Comparing Example 5 and Effect Example 6, it is found that after the mass ratio of the polymer P(AN-co-AM) to NIPAM changes from 1:1 to 1:2, the thermal response effect of the LCST segment of the polymer is significantly improved. It can be seen from the three Effect Examples that when the temperature is higher than about 34 °C, the polymer exhibits the LCST phenomenon, but the length of the poly(N-isopropylacrylamide) (PNIPAM) molecular chain segment in the molecule will affect the thermal response performance of the polymer. Moreover, the thermal response behavior of the UCST segment P(AN-co-AM) will also be affected by the LCST segment, showing different cloud points.

[0087] Effect Example 7

[0088] Effect Example 7 is carried out on the basis of Effect Example 6. Using the 1 mg / mL polymer P(AN-co-AM)-b-PNIPAM solution of Example 6, write the three letters "AIM" under the solution, and record the clarity of the letters at different temperatures.

[0089] For further verification, a simple verification was carried out using the light transmittance of the solution. Taking the temperature changes in autumn and spring as an example. As Figure 8 shown in b, when the sun rises during the day and the temperature increases, the smart window becomes transparent due to the increase in the external temperature, playing a good role in indoor lighting. If it encounters high-temperature weather and the outdoor temperature is too high, as Figure 8 shown in c, the smart window will gradually change from a transparent state to an opaque state, reducing the transmittance of ultraviolet rays and playing a good role in indoor heat insulation. When night comes and the external temperature further drops below the thermal response temperature, as Figure 8 shown in a, the smart window is also in an opaque state at this time, playing a good role in privacy protection at night. Even if the lights are on indoors, the outside world still cannot see inside. This kind of smart window is adjusted only by temperature and does not waste any energy. At the same time, by adjusting the monomer ratio of the block copolymer P(AN-co-AM)-b-PNIPAM, the thermal response temperature of the smart window can be adjusted, thereby adjusting the light transmittance of the light smart window.

[0090] The preparation method of the thermal response smart window dimming device provided in this example is as follows:

[0091] The smart window device mainly consists of three parts. As Figure 9 shown, it includes a first transparent glass substrate 10 and a second transparent substrate 11, a sealing rubber ring 22, and a block copolymer solution. A sealing rubber ring is sandwiched between the two glass substrates, and the two are closely fitted. The block copolymer solution is injected through the solution injection port 33 in the airspace between the sealing ring and the substrate. After that, a plug or other solid sealing grease is used for sealing.

[0092] The above has made a detailed description in connection with the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art to which the present invention pertains.

Claims

1. A block copolymer, characterized in that, The block copolymer is obtained by copolymerizing a nonionic polymer with a high critical solution temperature and a nonionic polymer with a low critical solution temperature; wherein, the thermal response temperature value of the nonionic polymer with a high critical solution temperature is less than that of the nonionic polymer with a low critical solution temperature; the nonionic polymer with a high critical solution temperature is selected from poly(acrylonitrile-co-acrylamide) random copolymer; the nonionic polymer with a low critical solution temperature is selected from poly(N-isopropylacrylamide) homopolymer; in the poly(acrylonitrile-co-acrylamide) random copolymer, the molar ratio of acrylonitrile monomer to acrylamide monomer is 1:1 to 3; the mass ratio of the nonionic polymer with a high critical solution temperature to the nonionic polymer with a low critical solution temperature is 1:(1 to 2).

2. The block copolymer according to claim 1, characterized in that, The thermal response temperature value of the nonionic polymer with a high critical solution temperature is 10°C to 30°C.

3. A thermally responsive dimming device, characterized in that, It includes a first light-transmitting substrate and a second light-transmitting substrate arranged oppositely, and a dimming area is encapsulated between the first light-transmitting substrate and the second light-transmitting substrate. The dimming area includes the block copolymer and a polar solvent described in claim 1 or 2.

4. The thermally responsive dimming device according to claim 3, wherein The concentration of the block copolymer is ≥1 mg / mL.

5. The preparation method of the thermoresponsive dimming device according to claim 3 or 4, characterized in that, It includes the following steps: S1. Cure and encapsulate the first light-transmitting substrate and the second light-transmitting substrate to form a dimming area; S2. Fill the block copolymer and the polar solvent into the dimming area under negative pressure to obtain a thermoresponsive dimming device.

6. Application of the dimming device described in claim 3 or 4 in an intelligent window.

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