Variable-emissivity film for enhancing contrast ratio of infrared simulator and preparation method of variable-emissivity film

Abstract

The invention discloses a variable-emissivity film for enhancing the contrast ratio of an infrared simulator and a preparation method of the variable-emissivity film, and relates to the field of advanced functional materials.The variable-emissivity film comprises an infrared transparent protective layer, a self-adaptive variable-emissivity functional layer, an infrared transparent interlayer and a low-infrared-emissivity substrate from top to bottom; the self-adaptive variable-emissivity functional layer is prepared by introducing a sultone ring with a thermal response ring opening characteristic into a polyaniline polymer, and the protonic acid doping degree of the polyaniline polymer can be changed after ring opening and closing of the sultone ring structure at different temperatures; by comprehensively utilizing the infrared characteristics of the low-infrared-emissivity substrate and the self-adaptive variable-emissivity functional layer, the self-adaptive variable-emissivity film can show higher and lower infrared emissivity at high and low temperatures, so that the radiation contrast of a thermal radiation pixel unit of the thermal infrared imaging equipment is enhanced; the method does not need to change the original structure of the thermal infrared imaging equipment, and has the advantages of low cost, good equipment compatibility and the like.

Description

Technical Field

[0001] The present invention relates to the field of advanced functional materials, and in particular to a variable emissivity film for enhancing the contrast of an infrared simulator and a preparation method thereof, and specifically to an adaptive variable emissivity film for enhancing the contrast of an infrared scene simulator and a preparation method thereof. Background Art

[0002] According to the Stefan-Boltzmann theorem, the surface thermal radiation intensity of an object is related to its surface temperature and surface emissivity. In an infrared scene simulator, the emissivity of each pixel unit on the resistor array is fixed. Therefore, the infrared scene simulator usually changes the infrared radiation intensity of a single pixel unit by adjusting the temperature of the single pixel unit in the resistor array. In this case, the difference in thermal radiation intensity of different pixel units on the resistor array is completely determined by their temperature difference.

[0003] By designing an adaptive variable emissivity film on the resistor array, the resistor array can be given the ability to change thermal radiation under the stimulation of the resistor array temperature. Under the condition of a fixed temperature difference between pixel units on the resistor array, the difference in thermal radiation intensity on the surface of the resistor array can be increased, thereby enhancing the contrast of the infrared scene simulator.

[0004] Currently available variable emissivity control technologies include micro thermal control shutters, electro-variable emissivity, thermo-variable emissivity, etc. Among them, micro thermal control shutters require complex mechanical structures, and electro-variable emissivity technology needs to be equipped with peripheral temperature sensors, power supply units, control units and other modules. Thermo-variable emissivity technology can achieve emissivity changes by relying on the different infrared properties of thermo-variable emissivity materials before and after phase change. Traditional thermo-variable emissivity materials such as V2O5 can only have emissivity changes within a limited phase change temperature range, which greatly limits its application in infrared scene simulators.

[0005] In summary, the existing variable emissivity technology is difficult to be used in the field of enhancing the contrast of infrared scene simulators. Therefore, the design of an adaptive variable emissivity film with a simple preparation method, easy integration with an infrared scene simulator, and whose emissivity can change with temperature has application value in enhancing the contrast of infrared scene simulators. Summary of the invention

[0006] In order to overcome the shortcomings of the background technology, the present invention provides a variable emissivity film for enhancing the contrast of an infrared simulator and a preparation method thereof. The present invention introduces a sultone ring as a modified functional group of a polyaniline polymer, and utilizes the reversible opening and closing of the sultone ring at high and low temperatures to achieve changes in the doping degree and infrared characteristics of the polyaniline polymer. The present invention uses aniline polymer materials as adaptive variable emissivity functional layer materials in the multilayer structure of an adaptive variable emissivity film, and comprehensively utilizes the infrared characteristics of the adaptive variable emissivity functional layer and a low infrared emissivity substrate to achieve adaptive changes in the emissivity of the adaptive variable emissivity film with temperature, thereby improving the contrast of the infrared scene simulator, etc.

[0007] In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solution: A variable emissivity film for enhancing the contrast of an infrared simulator comprises an infrared transparent protective layer, an adaptive variable emissivity functional layer, an infrared transparent interlayer, a metal reflective layer and a flexible base layer. A low infrared emissivity base is obtained after the metal reflective layer is deposited on the surface of the flexible base layer. An infrared transparent interlayer is attached to the upper surface of the low infrared emissivity base, an adaptive variable emissivity functional layer is coated on the upper surface of the infrared transparent interlayer, and an infrared transparent protective layer is attached to the upper surface of the adaptive variable emissivity functional layer.

[0008] The film with adaptive variable emissivity, the infrared transparent protective layer is composed of any one of polyethylene, polyethylene terephthalate, polyvinylidene fluoride, single crystal germanium or single crystal silicon, or a composite of two or more thereof, and the thickness of the infrared transparent protective layer is 0.01 to 5 mm.

[0009] The film with adaptive variable emissivity, the material of the adaptive variable emissivity functional layer is a polyaniline derivative.

[0010] In the film with adaptive variable emissivity, the main chain of the polyaniline derivative is polyaniline, and the side chain has 3,3-di(4-hydroxyphenyl)-3H-2,1-benzoxathiolane-1,1-dioxide analogues which are connected to the main chain of polyaniline via bridging groups.

[0011] The film with adaptive variable emissivity, the infrared transparent interlayer is composed of any one of polyethylene, polyethylene terephthalate, polyvinylidene fluoride, single crystal germanium, single crystal silicon, or a composite of two or more thereof.

[0012] The thickness of the infrared transparent interlayer of the film with adaptive variable emissivity is 0.01-5 mm.

[0013] The self-adaptive variable emissivity film, the metal reflective layer is made of any one of gold, silver, copper, iron, and aluminum, or an alloy of two or more of them, and the thickness of the metal reflective layer is 0.01 to 5 μm.

[0014] The film with adaptive variable emissivity, the flexible base layer is composed of any one of polyethylene film, polytetrafluoroethylene film, polyimide film, thermal conductive silicone rubber, thermal conductive graphene or a composite of two or more thereof, and the thickness of the flexible base layer is 0.01 to 5 mm.

[0015] The thickness of the film with adaptive variable emissivity and the low infrared emissivity substrate is 0.01-5 mm.

[0016] A method for preparing a variable emissivity film for enhancing the contrast of an infrared simulator, the preparation method specifically comprising the following steps: Step 1: Prepare a low infrared emissivity substrate: Electron beam evaporation deposition was performed on the flexible substrate using a high-purity gold target. The vacuum during deposition was 1×10 -5 ~3×10 -3 Pa, and the deposition thickness is measured by using a film thickness meter to determine that the thickness of the deposited pure gold metal reflective layer is 0.01 to 5 μm, that is, a low infrared emissivity substrate is obtained; Step 2: Prepare an infrared transparent interlayer on the surface of a low infrared emissivity substrate: The infrared transparent interlayer and the low infrared emissivity substrate obtained in the first step are placed in a vacuum chamber for 0.5 to 10 minutes, the air between the layers is removed to avoid bubbling, and the infrared transparent interlayer and the low infrared emissivity substrate are pressed at 80 to 200° C. using a hot press to make them fit together, that is, the infrared transparent interlayer is prepared on the surface of the low infrared emissivity substrate; Step 3: Prepare an adaptive variable emission functional layer on the surface of the infrared transparent interlayer: Dissolve the adaptive variable emission functional material in 5-20 mL N-methylpyrrolidone, stir at a speed of 50-5000 r / min for 1-7 days, and take a size of 1-10000 mm 2 A low infrared emissivity substrate having an infrared transparent interlayer 3 on its surface is used as a spin coating substrate, 5 to 500 μL of an N-methylpyrrolidone solution containing an adaptive variable emission functional material is taken and evenly dropped on the spin coating substrate; first, the substrate is spin coated at a speed of 50 to 2000 r / min for 5 to 500 s, and then the substrate is spin coated at a speed of 50 to 5000 r / min for 1 to 100 s. After the spin coating, the substrate is vacuum dried overnight to prepare an adaptive variable emission functional layer on the surface of the spin coating substrate; Step 4: Encapsulate an infrared transparent protective layer on the surface of the adaptive variable emissivity functional layer: An infrared transparent protective layer is placed on the surface of the adaptive variable emissivity functional layer, and then hot pressing is performed on it at a temperature of 80 to 200° C. to obtain an adaptive variable emissivity film.

[0017] The preparation method of the film with adaptive variable emissivity, the preparation method of the adaptive variable emissivity functional material in the third step is firstly adding 1-50g of o-sulfonylbenzoyl anhydride and 1-200g of o-chlorophenol into a nitrogen-protected three-necked bottle in sequence, and heating to 130-140°C to completely melt the two; Add 1-5g of anhydrous zinc chloride into a three-necked flask and react at 80-200℃ for 1-20 hours; Add 5-500 ml of deionized water into a three-necked bottle and stir continuously until the odor of o-chlorophenol disappears; The product was obtained by filtration and purified by silica gel column chromatography to obtain 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide; In an ice water bath, dissolve 1-5 g of aniline monomer and 1-5 g of o-hydroxyaniline monomer in 5-500 ml of 0.5-5 mol / L HCl solution, and ultrasonicate for 5-20 min until all are dissolved; Dissolve 1-5 g of ammonium persulfate in 5-100 ml of 0.5-5 mol / L HCl solution; Under nitrogen protection, the HCl solution of ammonium persulfate is added dropwise to the HCl solution of aniline and o-hydroxyaniline, and after stirring for 1 to 10 hours in an ice-water bath, the mixed solution is filtered to obtain a filter cake; The obtained filter cake is washed 1 to 5 times with a 0.5 to 5 mol / L hydrochloric acid solution, and then washed 1 to 5 times with deionized water, and finally centrifuged at a speed of 100 to 2000 r / min for 10 to 100 minutes, and the obtained precipitate is dried at 50 to 200° C. for 1 to 20 hours, and ground to obtain a copolymer of aniline and o-hydroxyaniline; Add aniline and o-hydroxyaniline copolymer, 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide and potassium hydroxide into purified tetrahydrofuran, and stir at 10-40°C for 1-20 min; 1,6-dibromoethane is added dropwise to the reaction solution, and the entire reaction solution is refluxed at 60-200°C for 1-72h; After the reaction liquid is cooled to room temperature, 10 to 2000 mL of water is added to the reaction liquid, and the organic phases are combined after extraction with dichloromethane for 1 to 5 times, dried with anhydrous sodium sulfate, and then distilled under reduced pressure to obtain a polyaniline derivative having 3,3-di(3,4-dihydroxyphenyl)-3H-2,1-benzothiophene-1,1-dioxide on the side chain, which is the adaptive variable emissivity material.

[0018] By adopting the above technical solution, the present invention has the following advantages: The invention comprises an infrared transparent protective layer, an adaptive variable emissivity functional layer, an infrared transparent interlayer and a low infrared emissivity substrate from top to bottom. The invention prepares an adaptive variable emissivity functional layer by introducing a sultone ring with a thermal response opening ring characteristic into a polyaniline polymer. The sultone ring structure changes the proton acid doping degree of the polyaniline polymer after the ring opening and closing at different temperatures. The infrared characteristics of the low infrared emissivity substrate and the adaptive variable emissivity functional layer are comprehensively utilized. The adaptive variable emissivity film can show higher and lower infrared emissivity at high and low temperatures, thereby enhancing the radiation contrast of the thermal radiation pixel unit of the thermal infrared imaging device. The invention does not need to change the original structure of the thermal infrared imaging device, has the advantages of low cost and good device compatibility, and has great application potential in the field of enhancing the radiation contrast of the thermal infrared imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the adaptive variable emissivity film for enhancing the contrast of an infrared scene simulator according to the present invention; Figure 2 A schematic diagram of the chemical structure of the adaptive variable emission functional layer material of the present invention; Figure 3 This is a schematic diagram of the working principle of the adaptive variable emission functional layer material of the present invention; Figure 4 A schematic diagram of the working principle of the adaptive variable emissivity film for enhancing the contrast of an infrared scene simulator according to the present invention; Figure 5 Schematic diagram of the synthesis route of the adaptive variable emissivity material prepared in Example 1; In the figure: 1. Infrared transparent protective layer; 2. Adaptive variable emission functional layer; 3. Infrared transparent interlayer; 4. Metal reflective layer; 5. Flexible base layer. DETAILED DESCRIPTION

[0020] The present invention can be explained in more detail by the following examples, but the present invention is not limited to the following examples; The implementation principle of the present invention is as follows: like Figure 3 and Figure 4As shown in the figure, after the adaptive variable emissivity film is placed on the resistor array of the infrared scene simulator, if the resistor array is in a low temperature state, the sultone ring of the adaptive variable emissivity functional layer material in the adaptive variable emissivity film is in a closed state, the polyaniline main chain is not doped, and the infrared transmittance is high. At this time, the adaptive variable emissivity film exhibits low infrared emissivity characteristics due to the low infrared emissivity substrate at the bottom. As the temperature of the resistor array increases, the sultone ring of the adaptive variable emissivity functional layer material will open, generate sulfonate and dope the polyaniline main chain. After the polyaniline main chain is doped with acid, the infrared absorption is enhanced and the infrared transmittance is reduced. At this time, the adaptive variable emissivity film exhibits high infrared emissivity characteristics due to the low infrared transmittance of the adaptive variable emissivity functional layer material. The emissivity of the adaptive variable emissivity film can rise and fall with the rise and fall of the resistor array temperature, making the infrared radiation difference of different resistor array units more obvious, thereby enhancing the contrast of the infrared scene simulator.

[0021] Combined with Figures 1 to 5 , the film of the present invention having an adaptive variable emissivity, such as Figure 1 As shown, it includes an infrared transparent protective layer 1, an adaptive variable emission functional layer 2, an infrared transparent interlayer 3, a metal reflective layer 4 and a flexible substrate layer 5. After the metal reflective layer 4 is deposited on the surface of the flexible substrate layer 5, a low infrared emissivity substrate is obtained, a layer of infrared transparent interlayer 3 is adhered to the upper surface of the low infrared emissivity substrate, a layer of adaptive variable emission functional layer 2 is coated on the upper surface of the infrared transparent interlayer 3, and a layer of infrared transparent protective layer 1 is adhered to the upper surface of the adaptive variable emission functional layer 2.

[0022] During implementation, the infrared transparent protective layer 1 is made of any one of polyethylene, polyethylene terephthalate, polyvinylidene fluoride, single crystal germanium or single crystal silicon, or a composite of two or more thereof, and the thickness of the infrared transparent protective layer 1 is 0.01-5 mm.

[0023] Furthermore, the material of the adaptive variable emission functional layer 2 is a polyaniline derivative.

[0024] Furthermore, the main chain of the polyaniline derivative is polyaniline, and its side chain has 3,3-di(4-hydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide analogs connected to the polyaniline main chain through bridging groups; during implementation, the molecular structure of the adaptive variable emission functional layer material is as follows Figure 2 As shown, R1 is a bridging functional group, specifically an alkyl chain, an ether chain, an oxygen chain, a sulfur chain, or a nitrogen chain; R2 and R3 are organic functional groups, specifically hydrogen, an alkyl group, a phenyl group, a halogen-containing group, a nitrogen-containing group, a sulfur-containing group, or a phosphorus-containing group.

[0025] Furthermore, the infrared transparent interlayer 3 is made of any one of polyethylene, polyethylene terephthalate, polyvinylidene fluoride, single crystal germanium, and single crystal silicon, or a composite of two or more thereof, and the thickness of the infrared transparent interlayer 3 is 0.01 to 5 mm.

[0026] Furthermore, the metal reflective layer 4 is made of any one of gold, silver, copper, iron, and aluminum, or an alloy of two or more of them, and the thickness of the metal reflective layer 4 is 0.01 to 5 μm.

[0027] Furthermore, the flexible base layer 5 is composed of any one of polyethylene film, polytetrafluoroethylene film, polyimide film, thermal conductive silicone rubber, thermal conductive graphene, or a composite of two or more thereof, and the thickness of the flexible base layer 5 is 0.01 to 5 mm.

[0028] Furthermore, the thickness of the low infrared emissivity substrate is 0.01 to 5 mm.

[0029] A method for preparing a variable emissivity film for enhancing the contrast of an infrared simulator, the preparation method specifically comprising the following steps: Step 1: Prepare a low infrared emissivity substrate: Electron beam evaporation deposition is performed on the flexible substrate layer 5 using a high-purity gold target material. The vacuum degree during deposition is 1×10 -5 ~3×10 -3 Pa, and the deposition thickness is measured using a film thickness meter to determine that the thickness of the deposited pure gold metal reflective layer 4 is 0.01 to 5 μm, that is, a low infrared emissivity substrate is obtained; Step 2: Prepare an infrared transparent interlayer on the surface of a low infrared emissivity substrate: The infrared transparent interlayer 3 and the low infrared emissivity substrate obtained in the first step are placed in a vacuum chamber for 0.5 to 10 minutes, the air between the layers is removed to avoid bubbling, and the infrared transparent interlayer 3 and the low infrared emissivity substrate are pressed at 80 to 200° C. using a hot press to make them fit together, that is, the infrared transparent interlayer 3 is prepared on the surface of the low infrared emissivity substrate; Step 3: Prepare an adaptive variable emission functional layer on the surface of the infrared transparent interlayer: Dissolve the adaptive variable emission functional material in 5-20 mL N-methylpyrrolidone, stir at a speed of 50-5000 r / min for 1-7 days, and take a size of 1-10000 mm 2A low infrared emissivity substrate having an infrared transparent interlayer 3 on its surface is used as a spin coating substrate, 5 to 500 μL of an N-methylpyrrolidone solution containing an adaptive variable emission functional material is taken and evenly dropped on the spin coating substrate; first, the substrate is spin coated at a speed of 50 to 2000 r / min for 5 to 500 s, and then the substrate is spin coated at a speed of 50 to 5000 r / min for 1 to 100 s. After the spin coating, the substrate is vacuum dried overnight to prepare an adaptive variable emission functional layer 2 on the surface of the spin coating substrate; Step 4: Encapsulate an infrared transparent protective layer on the surface of the adaptive variable emissivity functional layer: An infrared transparent protective layer 1 is placed on the surface of the adaptive variable emissivity functional layer 2, and then hot-pressed at a temperature of 80-200°C to obtain an adaptive variable emissivity film.

[0030] The preparation method of the film with adaptive variable emissivity, the preparation method of the adaptive variable emissivity functional material in the third step is firstly adding 1-50g of o-sulfonylbenzoyl anhydride and 1-200g of o-chlorophenol into a nitrogen-protected three-necked bottle in sequence, and heating to 130-140°C to completely melt the two; Add 1-5g of anhydrous zinc chloride into a three-necked flask and react at 80-200℃ for 1-20 hours; Add 5-500 ml of deionized water into a three-necked bottle and stir continuously until the odor of o-chlorophenol disappears; The product was obtained by filtration and purified by silica gel column chromatography to obtain 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide; In an ice water bath, dissolve 1-5 g of aniline monomer and 1-5 g of o-hydroxyaniline monomer in 5-500 ml of 0.5-5 mol / L HCl solution, and ultrasonicate for 5-20 min until all are dissolved; Dissolve 1-5 g of ammonium persulfate in 5-100 ml of 0.5-5 mol / L HCl solution; Under nitrogen protection, the HCl solution of ammonium persulfate is added dropwise to the HCl solution of aniline and o-hydroxyaniline, and after stirring for 1 to 10 hours in an ice-water bath, the mixed solution is filtered to obtain a filter cake; The obtained filter cake is washed 1 to 5 times with a 0.5 to 5 mol / L hydrochloric acid solution, and then washed 1 to 5 times with deionized water, and finally centrifuged at a speed of 100 to 2000 r / min for 10 to 100 minutes, and the obtained precipitate is dried at 50 to 200° C. for 1 to 20 hours, and ground to obtain a copolymer of aniline and o-hydroxyaniline; Add aniline and o-hydroxyaniline copolymer, 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide and potassium hydroxide into purified tetrahydrofuran, and stir at 10-40°C for 1-20 min; 1,6-dibromoethane is added dropwise to the reaction solution, and the entire reaction solution is refluxed at 60-200°C for 1-72h; After the reaction liquid is cooled to room temperature, 10 to 2000 mL of water is added to the reaction liquid, and the organic phases are combined after extraction with dichloromethane for 1 to 5 times, dried with anhydrous sodium sulfate, and then distilled under reduced pressure to obtain a polyaniline derivative having 3,3-di(3,4-dihydroxyphenyl)-3H-2,1-benzothiophene-1,1-dioxide on the side chain, which is the adaptive variable emissivity material.

[0031] A specific embodiment of a method for preparing a variable emissivity film for enhancing the contrast of an infrared simulator is as follows: Embodiment 1:

[0032] The preparation method specifically comprises the following steps: Step 1: Prepare a low infrared emissivity substrate: A thermally conductive silicone rubber with a thickness of 5 mm was used as the flexible substrate layer, and a high-purity gold target was used for electron beam evaporation deposition. The vacuum degree during deposition was 3.00×10 -3 Pa, and the deposition thickness was measured using a film thickness meter, and it was determined that the thickness of the deposited pure gold metal reflective layer was 5 μm, that is, a low infrared emissivity substrate was obtained.

[0033] Step 2: Prepare an infrared transparent interlayer on the surface of a low infrared emissivity substrate: A polyethylene film with a thickness of 5 mm was used as an infrared transparent interlayer. The polyethylene film and the low infrared emissivity substrate were placed in a vacuum chamber for 10 min, and the air between the layers was removed to avoid bubbling. The polyethylene film and the low infrared emissivity substrate were hot-pressed at 200°C using a hot press to bond them together, thus preparing an infrared transparent interlayer on the surface of the low infrared emissivity substrate.

[0034] Step 3: Prepare an adaptive variable emission functional layer on the surface of the infrared transparent interlayer: The synthesis route of adaptive variable emissivity materials is as follows Figure 5 As shown, 50 g of o-sulfonylbenzoyl anhydride and 200 g of o-chlorophenol were added into a three-necked flask protected by nitrogen in sequence, and heated to 140°C to completely melt the two. Add 5 g of anhydrous zinc chloride into a three-necked flask and react at 200 °C for 20 h; Add 500 ml of deionized water into the three-necked flask and stir continuously until the odor of o-chlorophenol disappears; The product was filtered and purified by silica gel column chromatography (using ethyl acetate / dichloromethane with a volume ratio of 1:1 as eluent) to obtain 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide; In an ice-water bath, 5 g of aniline monomer and 5 g of o-hydroxyaniline monomer were dissolved in 500 ml of 5 mol / L HCl solution and ultrasonicated for 20 min until they were completely dissolved. Dissolve 5 g of ammonium persulfate in 100 ml of 5 mol / L HCl solution; Under nitrogen protection, the HCl solution of ammonium persulfate was added dropwise to the HCl solution of aniline and o-hydroxyaniline, and after stirring for 10 h in an ice-water bath, the mixed solution was filtered to obtain a filter cake; The obtained filter cake was washed 5 times with 5 mol / L hydrochloric acid solution and then washed 5 times with deionized water, and finally centrifuged at 2000 r / min for 100 min. The obtained precipitate was dried at 200°C for 20 h and ground to obtain the copolymer of aniline and o-hydroxyaniline. Add aniline and o-hydroxyaniline copolymer, 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide and potassium hydroxide into purified tetrahydrofuran and stir at 40°C for 20 min; 1,6-Dibromoethane was added dropwise to the reaction solution, and the entire reaction solution was refluxed at 200 °C for 72 h; After the reaction liquid is cooled to room temperature, 2000 mL of water is added to the reaction liquid, and the organic phases are combined after extraction with dichloromethane for 5 times, dried with anhydrous sodium sulfate, and then distilled under reduced pressure to obtain a polyaniline derivative having 3,3-di(3,4-dihydroxyphenyl)-3H-2,1-benzothiophene-1,1-dioxide on the side chain, which is the adaptive variable emissivity material; 0.2 g of the adaptive variable emissivity material was dissolved in 20 mL of N-methylpyrrolidone and stirred at 5000 r / min for 7 days; Take the size as 1000 mm 2 A low infrared emissivity substrate with an infrared transparent interlayer on the surface is used as a spin coating substrate, and 500 μL of N-methylpyrrolidone solution containing adaptive variable emissivity material is evenly dropped on the spin coating substrate; First, the substrate was spin-coated at a speed of 2000 r / min for 500 s, and then at a speed of 5000 r / min for 100 s. After spin-coating, the substrate was vacuum-dried overnight to prepare an adaptive variable emission functional layer on the surface of the spin-coated substrate. Step 4: Encapsulate an infrared transparent protective layer on the surface of the adaptive variable emissivity functional layer: A 5 mm polyethylene film was used as an infrared transparent protective layer, and the multilayer structure containing an adaptive variable emissivity functional layer, an infrared transparent interlayer, and a low infrared emissivity substrate was hot pressed at a temperature of 200 °C to obtain an adaptive variable emissivity film. Embodiment 2:

[0035] The preparation method specifically comprises the following steps: Step 1: Prepare a low infrared emissivity substrate: Polyimide with a thickness of 0.1 mm was used as the flexible substrate layer, and high-purity gold target was used for electron beam evaporation deposition. The vacuum degree during deposition was 2.00×10 -3 Pa, and the deposition thickness was measured using a film thickness meter, and it was determined that the thickness of the deposited pure gold metal reflective layer was 5 μm, that is, a low infrared emissivity substrate was obtained.

[0036] Step 2: Prepare an infrared transparent interlayer on the surface of a low infrared emissivity substrate: A 0.01 mm thick polyvinylidene fluoride film was used as an infrared transparent interlayer. The polyvinylidene fluoride film and the low infrared emissivity substrate were placed in a vacuum chamber for 5 min, and the air between the layers was removed to avoid bubbling. A hot press was used to heat press the polyvinylidene fluoride film and the low infrared emissivity substrate at 140°C and bond them together, thus preparing an infrared transparent interlayer on the surface of the low infrared emissivity substrate.

[0037] Step 3: Prepare an adaptive variable emission functional layer on the surface of the infrared transparent interlayer: The synthesis route of adaptive variable emissivity materials is as follows Figure 5 As shown, 27.6 g of o-sulfonylbenzoyl anhydride and 56.7 g of o-chlorophenol were added into a three-necked bottle protected by nitrogen in sequence, and heated to 140°C to completely melt the two. Add 19.5 g of anhydrous zinc chloride into a three-necked flask and react at 140 °C for 7 h; Add 75 ml of deionized water into the three-necked flask and stir continuously until the odor of o-chlorophenol disappears; The product was filtered and purified by silica gel column chromatography (using ethyl acetate / dichloromethane with a volume ratio of 1:1 as eluent) to obtain 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide; In an ice-water bath, 1.5 g of aniline monomer and 1.5 g of o-hydroxyaniline monomer were dissolved in 150 ml of 1 mol / L HCl solution and ultrasonicated for 15 min until all dissolved. Dissolve 7.35 g of ammonium persulfate in 60 ml of 1 mol / L HCl solution; Under nitrogen protection, the HCl solution of ammonium persulfate was added dropwise to the HCl solution of aniline and o-hydroxyaniline, and after stirring for 6 h in an ice-water bath, the mixed solution was filtered to obtain a filter cake; The obtained filter cake was washed 4 times with 1 mol / L hydrochloric acid solution and then washed 4 times with deionized water, and finally centrifuged at 2000 r / min for 30 min. The obtained precipitate was dried at 85°C for 12 h and ground to obtain a copolymer of aniline and o-hydroxyaniline. Add aniline and o-hydroxyaniline copolymer, 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide and potassium hydroxide into purified tetrahydrofuran and stir at 20°C for 6 min; 1,6-Dibromoethane was added dropwise to the reaction solution, and the entire reaction solution was refluxed at 80 °C for 24 h; After the reaction liquid is cooled to room temperature, 150 mL of water is added to the reaction liquid, and the organic phases are combined after extraction with dichloromethane for 3 times, dried with anhydrous sodium sulfate, and then distilled under reduced pressure to obtain a polyaniline derivative having 3,3-di(3,4-dihydroxyphenyl)-3H-2,1-benzothiophene-1,1-dioxide on the side chain, which is the adaptive variable emissivity material; 0.3 g of adaptive variable emissivity material was dissolved in 20 mL of N-methylpyrrolidone and stirred at 800 r / min for 7 days; Take the size of 500 mm 2 A low infrared emissivity substrate with an infrared transparent interlayer on the surface is used as a spin coating substrate, and 70 μL of N-methylpyrrolidone solution containing the adaptive variable emissivity material is evenly dropped on the spin coating substrate; First, the substrate was spin-coated at a speed of 500 r / min for 300 s, and then at a speed of 5000 r / min for 10 s. After spin-coating, the substrate was vacuum dried overnight, and an adaptive variable emission functional layer was prepared on the surface of the spin-coated substrate. Step 4: Encapsulate an infrared transparent protective layer on the surface of the adaptive variable emissivity functional layer: A 0.05 mm polyethylene film was used as an infrared transparent protective layer, and a multilayer structure containing an adaptive variable emissivity functional layer, an infrared transparent interlayer, and a low infrared emissivity substrate was hot pressed at a temperature of 130 °C to obtain an adaptive variable emissivity film. Embodiment three:

[0038] The preparation method specifically comprises the following steps: Step 1: Prepare a low infrared emissivity substrate: Thermally conductive graphene with a thickness of 0.01 mm was used as the flexible substrate layer, and high-purity silver target was used for electron beam evaporation deposition. The vacuum degree during deposition was 1×10-5 Pa, and the deposition thickness was measured using a film thickness meter, and it was determined that the thickness of the deposited pure silver metal reflective layer was 0.01 μm, that is, a low infrared emissivity substrate was obtained.

[0039] Step 2: Prepare an infrared transparent interlayer on the surface of a low infrared emissivity substrate: A polyethylene film with a thickness of 0.01 mm was used as an infrared transparent interlayer. The polyethylene film and the low infrared emissivity substrate were placed in a vacuum chamber for 0.5 min, and the air between the layers was removed to avoid bubbling. A hot press was used to heat press the polyethylene film and the low infrared emissivity substrate at 80°C and bond them together, thus preparing an infrared transparent interlayer on the surface of the low infrared emissivity substrate.

[0040] Step 3: Prepare an adaptive variable emission functional layer on the surface of the infrared transparent interlayer: The synthesis route of adaptive variable emissivity materials is as follows Figure 5 As shown, 1 g of o-sulfonylbenzoyl anhydride and 1 g of o-chlorophenol were added into a three-necked flask protected by nitrogen in sequence, and heated to 130°C to completely melt the two. Add 1 g of anhydrous zinc chloride into a three-necked flask and react at 80 °C for 1 h; Add 5 ml of deionized water into the three-necked bottle and stir continuously until the odor of o-chlorophenol disappears; The product was filtered and purified by silica gel column chromatography (using ethyl acetate / dichloromethane with a volume ratio of 1:1 as eluent) to obtain 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide; In an ice-water bath, dissolve 1 g of aniline monomer and 1 g of o-hydroxyaniline monomer in 5 ml of 0.5 mol / L HCl solution and sonicate for 5 min until all dissolved. Dissolve 1 g of ammonium persulfate in 5 ml of 0.5 mol / L HCl solution; Under nitrogen protection, the HCl solution of ammonium persulfate was added dropwise to the HCl solution of aniline and o-hydroxyaniline, and after stirring for 1 h in an ice-water bath, the mixed solution was filtered to obtain a filter cake; The obtained filter cake was washed once with 1 mol / L hydrochloric acid solution and once with deionized water, and finally centrifuged at 100 r / min for 10 min. The obtained precipitate was dried at 50°C for 1 h and ground to obtain a copolymer of aniline and o-hydroxyaniline. Add aniline and o-hydroxyaniline copolymer, 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide and potassium hydroxide into purified tetrahydrofuran and stir at 10°C for 1 min; 1,6-Dibromoethane was added dropwise to the reaction solution, and the entire reaction solution was refluxed at 60 °C for 1 h; After the reaction liquid is cooled to room temperature, 20 mL of water is added to the reaction liquid, and the organic phases are combined after extraction with dichloromethane once, dried with anhydrous sodium sulfate, and then distilled under reduced pressure to obtain a polyaniline derivative having 3,3-di(3,4-dihydroxyphenyl)-3H-2,1-benzothiophene-1,1-dioxide on the side chain, which is the adaptive variable emissivity material; Take 0.4 g of adaptive variable emissivity material and dissolve it in 5 mL of N-methylpyrrolidone, and stir it at a speed of 50 r / min for 1 day; Take the size as 1 mm 2 A low infrared emissivity substrate with an infrared transparent interlayer on its surface is used as a spin coating substrate, and 5 μL of N-methylpyrrolidone solution containing the adaptive variable emissivity material is evenly dropped on the spin coating substrate; First, the substrate was spin-coated at a speed of 50 r / min for 5 s, and then at a speed of 50 r / min for 1 s. After spin-coating, the substrate was vacuum dried overnight, and an adaptive variable emission functional layer was prepared on the surface of the spin-coated substrate. Step 4: Encapsulate an infrared transparent protective layer on the surface of the adaptive variable emissivity functional layer: A 0.01 mm polyethylene film was used as an infrared transparent protective layer, and a multilayer structure containing an adaptive variable emissivity functional layer, an infrared transparent interlayer, and a low infrared emissivity substrate was hot pressed at a temperature of 80 °C to obtain an adaptive variable emissivity film.

[0041] The present invention introduces a sultone ring as a modified functional group of a polyaniline polymer, and utilizes the reversible opening and closing of the sultone ring at high and low temperatures to adjust the doping degree of polyaniline, so that the emissivity of the adaptive variable emissivity film can change with the change of temperature. Compared with the existing technologies such as micro thermal control shutters and electro-variable emissivity, the present invention has a simpler structure. Compared with the thermo-variable emissivity technology that can only make the emissivity change abruptly before and after the phase change temperature, the emissivity of the adaptive variable emissivity film can gradually change with the temperature change within a wider temperature range. Therefore, the present invention is particularly suitable for enhancing the contrast of infrared scene simulators, etc.

[0042] The parts not described in detail in this invention are prior art.

[0043] The embodiments selected herein for the purpose of disclosing the invention are currently considered to be suitable, but it should be understood that the invention is intended to include all changes and modifications of the embodiments that fall within the scope of the concept and invention.

Claims

1. A variable emissivity film for enhancing the contrast of an infrared simulator, comprising an infrared transparent protective layer (1), an adaptive variable emissivity functional layer (2), an infrared transparent interlayer (3), a metal reflective layer (4) and a flexible substrate layer (5), wherein: A low infrared emissivity substrate is obtained by depositing a metal reflective layer (4) on the surface of the flexible substrate layer (5); an infrared transparent interlayer (3) is adhered to the upper surface of the low infrared emissivity substrate; an adaptive variable emission functional layer (2) is coated on the upper surface of the infrared transparent interlayer (3); and an infrared transparent protective layer (1) is adhered to the upper surface of the adaptive variable emission functional layer (2).

2. The film with adaptive variable emissivity according to claim 1, characterized in that: The infrared transparent protective layer (1) is composed of any one of polyethylene, polyethylene terephthalate, polyvinylidene fluoride, single crystal germanium or single crystal silicon, or a composite of two or more of them.

3. The film with adaptive variable emissivity according to claim 1, characterized in that: The thickness of the infrared transparent protective layer (1) is 0.01 to 5 mm.

4. The film with adaptive variable emissivity according to claim 1, characterized in that: The material of the adaptive variable emission functional layer (2) is a polyaniline derivative.

5. The film with adaptive variable emissivity according to claim 4, characterized in that: The main chain of the polyaniline derivative is polyaniline, and the side chains thereof have 3,3-di(4-hydroxyphenyl)-3H-2,1-benzoxathiolane-1,1-dioxide analogs which are connected to the main chain of the polyaniline via a bridging group.

6. The film with adaptive variable emissivity according to claim 1, characterized in that: The infrared transparent interlayer (3) is composed of any one of polyethylene, polyethylene terephthalate, polyvinylidene fluoride, single crystal germanium, and single crystal silicon, or a composite of two or more thereof. The thickness of the infrared transparent interlayer (3) is 0.01 to 5 mm.

7. The film with adaptive variable emissivity according to claim 1, characterized in that: The metal reflective layer (4) is made of any one of gold, silver, copper, iron and aluminum, or an alloy of two or more of them. The thickness of the metal reflective layer (4) is 0.01 to 5 μm.

8. The film with adaptive variable emissivity according to claim 1, characterized in that: The flexible base layer (5) is composed of any one of polyethylene film, polytetrafluoroethylene film, polyimide film, thermal conductive silicone rubber, and thermal conductive graphene, or a composite of two or more thereof. The thickness of the flexible base layer (5) is 0.01 to 5 mm.

9. The film with adaptive variable emissivity according to claim 1, characterized in that: The thickness of the low infrared emissivity substrate is 0.01-5 mm.

10. The method for preparing the film with adaptive variable emissivity according to any one of claims 1 to 9, the method comprising the following steps: Step 1: Prepare a low infrared emissivity substrate: Electron beam evaporation deposition is performed on the flexible substrate layer (5) using a high-purity gold target material. The vacuum degree during deposition is 1×10 -5 ~3×10 -3 Pa, using a film thickness meter to measure the deposition thickness, and determining that the thickness of the deposited pure gold metal reflective layer (4) is 0.01 to 5 μm, that is, a low infrared emissivity substrate is obtained; Step 2: Prepare an infrared transparent interlayer on the surface of a low infrared emissivity substrate: The infrared transparent interlayer (3) and the low infrared emissivity substrate obtained in the first step are placed in a vacuum chamber for 0.5 to 10 minutes, the air between the layers is removed to avoid bubbling, and the infrared transparent interlayer (3) and the low infrared emissivity substrate are pressed at 80 to 200° C. using a hot press to make them fit together, so as to prepare the infrared transparent interlayer (3) on the surface of the low infrared emissivity substrate; Step 3: Prepare an adaptive variable emission functional layer on the surface of the infrared transparent interlayer: Dissolve the adaptive variable emission functional material in 5-20 mL N-methylpyrrolidone, stir at a speed of 50-5000 r / min for 1-7 days, and take a size of 1-10000 mm 2 A low infrared emissivity substrate having an infrared transparent interlayer (3) on its surface is used as a spin coating substrate, 5 to 500 μL of an N-methylpyrrolidone solution containing an adaptive variable emission functional material is taken and evenly dropped on the spin coating substrate; first, the substrate is spin coated at a speed of 50 to 2000 r / min for 5 to 500 s, then spin coated at a speed of 50 to 5000 r / min for 1 to 100 s, and then vacuum dried overnight after spin coating, thereby preparing an adaptive variable emission functional layer (2) on the surface of the spin coating substrate; Step 4: Encapsulate an infrared transparent protective layer on the surface of the adaptive variable emissivity functional layer: Placing an infrared transparent protective layer (1) on the surface of the adaptive variable emissivity functional layer (2), and then heat pressing the layer at a temperature of 80 to 200° C., thereby obtaining an adaptive variable emissivity film; The preparation method of the film with adaptive variable emissivity, the preparation method of the adaptive variable emissivity functional material in the third step is firstly adding 1-50g of o-sulfonylbenzoyl anhydride and 1-200g of o-chlorophenol into a nitrogen-protected three-necked bottle in sequence, and heating to 130-140°C to completely melt the two; Add 1-5g of anhydrous zinc chloride into a three-necked flask and react at 80-200℃ for 1-20 hours; Add 5-500 ml of deionized water into a three-necked bottle and stir continuously until the odor of o-chlorophenol disappears; The product was obtained by filtration and purified by silica gel column chromatography to obtain 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide; In an ice water bath, dissolve 1-5 g of aniline monomer and 1-5 g of o-hydroxyaniline monomer in 5-500 ml of 0.5-5 mol / L HCl solution, and ultrasonicate for 5-20 min until all are dissolved; Dissolve 1-5 g of ammonium persulfate in 5-100 ml of 0.5-5 mol / L HCl solution; Under nitrogen protection, the HCl solution of ammonium persulfate is added dropwise to the HCl solution of aniline and o-hydroxyaniline, and after stirring for 1 to 10 hours in an ice-water bath, the mixed solution is filtered to obtain a filter cake; The obtained filter cake is washed 1 to 5 times with a 0.5 to 5 mol / L hydrochloric acid solution, and then washed 1 to 5 times with deionized water, and finally centrifuged at a speed of 100 to 2000 r / min for 10 to 100 minutes, and the obtained precipitate is dried at 50 to 200° C. for 1 to 20 hours, and ground to obtain a copolymer of aniline and o-hydroxyaniline; Add aniline and o-hydroxyaniline copolymer, 3,3-bis(3,4-dihydroxyphenyl)-3H-2,1-benzothiolane-1,1-dioxide and potassium hydroxide into purified tetrahydrofuran, and stir at 10-40°C for 1-20 min; 1,6-dibromoethane is added dropwise to the reaction solution, and the entire reaction solution is refluxed at 60-200°C for 1-72 h; After the reaction liquid is cooled to room temperature, 10 to 2000 mL of water is added to the reaction liquid, and the organic phases are combined after extraction with dichloromethane for 1 to 5 times, dried with anhydrous sodium sulfate, and then distilled under reduced pressure to obtain a polyaniline derivative having 3,3-di(3,4-dihydroxyphenyl)-3H-2,1-benzothiophene-1,1-dioxide on the side chain, which is the adaptive variable emissivity material.

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