CN102876287A - Self assembly laminated infrared film material and preparation method of self assembly laminated infrared film material - Google Patents

Abstract

The object of the present invention is to provide a self-assembled laminated infrared film material and a preparation method thereof, which is formed by self-assembly of alternating layers of infrared absorbing material LDHs nanosheets and single-layer graphene oxide, and has LDHs The layer structure of nanosheet/single layer graphene oxide is sequentially stacked, the number of layers is 2~40, the material film thickness is 2~200nm, and the infrared emissivity of the material is 0.300~0.600 in the 8~14μm band at 25°C. The layered metal ions of LDHs nanosheets are composed of M ₁ metal ions and M ₂ metal ions, wherein the molar ratio of M ₁ metal ions to M ₂ metal ions is 2:1, and M ₁ metal ions are Mg ²⁺ , Co ²⁺ , Mn ²⁺ , Zn ²⁺ one or more combination, M ₂ metal ion is Fe ³⁺ , Co ³⁺ one or a combination of both.

Description

A self-assembled laminated infrared film material and its preparation method

technical field

The invention relates to a self-assembled laminated infrared film material and a preparation method thereof, which belongs to the preparation category of composite film materials and is suitable for preparing infrared low emissivity film materials.

Background technique

The development of infrared low emissivity materials has experienced the development from single component to composite material, from powder coating to film material. With the development of the film industry, materials with low infrared emissivity are moving closer to nano-membrane materials. emissivity. Chinese patent CN201210060305.2 discloses a fluorine-containing polyimide infrared low emissivity film material. Although it has a low infrared emissivity at 8-14 μm, the thickness of the film is not easy to control, and because it is formed by a polymer The thin film, the surface roughness of the material is relatively large, the internal structure is relatively disordered and the light transmission is poor.

Layered double hydroxides (LDHs) are a layered inorganic functional material with superior performance. Its main component is generally composed of two metal hydroxides. The three-dimensional structure formed by the alternating accumulation of anions between the plates and the layers. The interlayer spacing of LDHs varies with the metal ions of the layers and the types of anions between the layers. LDHs have been used as infrared absorbing materials in agricultural films, and their excellent infrared absorption effect It is mainly caused by the type and proportion of metal ions in the main layer of LDHs, the charge density and distribution of the main layer. The LDHs are stripped in a stripping solvent, and the positively charged LDHs nanosheets obtained have the characteristics of tunable metal ion composition of the laminate, tunable charge density and distribution of the laminate, and are ideal units for constructing electrostatically assembled membranes. Graphene, as another nano-scale functional material of the Fullerian carbon family, is obtained from the reduction of graphene oxide. In addition to excellent electrical properties, its mechanical properties are equivalent to those of single-walled carbon nanotubes. It is light in weight and good in thermal conductivity. And the surface area is large, and its large carrier density and carrier mobility are conducive to the reduction of its infrared emissivity. The surface of graphene oxide is rich in oxygen-containing functional groups, and it is dispersed in water to form a negative charge on the surface. monolayer graphene oxide in aqueous solution. Therefore, the layer-by-layer self-assembly of LDHs nanosheets and single-layer graphene oxide through electrostatic interaction can form a new laminated infrared film material, which has a layer structure of LDHs nanosheets/single-layer graphene oxide sequentially stacked, This endows it with unique optical properties, and the composition and thickness of the film material are controllable, the internal structure is orderly, the surface roughness of the film is small, and the light transmission is good. The invention provides a self-assembled laminated infrared film material, which is a promising new material for infrared stealth. Its research and application have potential economic and social benefits, and are very useful for both military and civilian uses. Good application prospects.

Contents of the invention

Technical problem: The purpose of this invention is to provide a self-assembled laminated infrared film material and its preparation method. The composition and structure of the material are controllable, the internal structure is orderly and the surface roughness is small, the thickness of the film is at the nanometer level, and the material has good light transmission, and can be used as an infrared low emissivity material.

Technical solution: A self-assembled laminated infrared film material of the present invention is characterized in that the material is self-assembled by alternating layers of layered double hydroxide LDHs nanosheets and single-layer graphene oxide as the unit, It has a layer structure of LDHs nanosheets/single-layer graphene oxide sequentially stacked, the number of layers is 2~40, the material film thickness is 2~200nm, and the infrared emission rate of the material is 0.300~0.600 at 25°C in the 8~14μm band. . The layered metal ions of LDHs nanosheets are composed of M ₁ metal ions and M ₂ metal ions, wherein the molar ratio of M ₁ metal ions to M ₂ metal ions is 2:1, and M ₁ metal ions are Mg ²⁺ , Co ²⁺ , Mn ²⁺ , Zn ²⁺ one or more combination, M ₂ metal ion is Fe ³⁺ , Co ³⁺ one or a combination of both.

The preparation method of the above-mentioned self-assembled laminated infrared film material is:

a) According to the molar ratio of carboxylic acid to _M2 metal is 5~10:1, add 0.2~1.0mol/L carboxylic acid aqueous solution and _M2 metal into the reaction kettle successively, react at room temperature for 4~10h, and then ₂ atmosphere, add 0.5~ _5.0mL 30wt% _H2O2 aqueous solution to the above reaction solution per gram of M2 metal for oxidation _reaction for 0.5~1h, and the molar ratio of _M1 metal to _M2 metal is 2:1, Then add _M1 metal and react at room temperature for 4~10h. After the reaction, use 8mol/L inorganic alkali aqueous solution to adjust the pH to 9.5~10.5, hydrothermal crystallization at 70~90℃ for 48~72h, cool, filter, and wash with deionized water for 4~6 Second, according to the molar ratio of _M2 metal to deionized water as 1:1000~5000, disperse with deionized water to obtain a suspension of carboxylate intercalated LDHs, and let it stand at 20~30°C for 24~48h to obtain LDHs nanosheet aqueous solution.

b) Add 20mL of alkyd mixed solution per square centimeter of substrate, the substrate is silicon wafer or quartz sheet, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, and the substrate is placed at room temperature Immerse in the alkyd mixed solution for 0.5~1h, take it out and wash it with deionized water for 10~15 times, add 10mL98wt% concentrated sulfuric acid per square centimeter substrate, then immerse the substrate in concentrated sulfuric acid for 0.5~1h, take it out and use it Ion washing 10~15 times, drying at room temperature under _N2 atmosphere for 2~10min, to obtain the modified substrate.

c) Add 40-100 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of the modified substrate, soak the modified substrate at room temperature for 5-15 minutes, take it out, wash it with deionized water 5-10 times, and Dry at room temperature for 2-8 minutes under N ₂ atmosphere to obtain LDHs assembly substrate.

d) Add 40~100mL 0.5~1mg/mL single-layer graphene oxide aqueous solution per square centimeter of LDHs assembly substrate, soak the LDHs assembly substrate prepared in step c) at room temperature for 5~15min, take it out, and rinse with deionized water Wash 5 to 10 times, and dry at room temperature for 2 to 8 minutes under _N2 atmosphere to obtain a self-assembled membrane material. The self-assembled membrane material is prepared by the method of step c) and step d) with LDHs nanosheets and single-layer graphene oxide Carry out 2~40 times of alternating layer-by-layer self-assembly for the primitive, and obtain the self-assembled laminated infrared film material.

The carboxylic acid described in the preparation step a) of the self-assembled laminated infrared film material is formic acid, acetic acid, propionic acid, oxalic acid, DL-lactic acid, L-lactic acid, benzoic acid, salicylic acid, L‐(+)‐ One of tartaric acid, D-(-)-tartaric acid, DL-tartaric acid, the inorganic base is NaOH or KOH.

Beneficial effects: the invention provides a self-assembled laminated infrared film material and a preparation method thereof. The composition and structure of the material can be adjusted, the internal structure is orderly, and the surface roughness is small.

The features of the present invention are:

(1) The carboxylate intercalated LDHs prepared by one-step method can effectively eliminate the interference of inorganic anions such as NO ₃ ^- , Cl ^- in the traditional LDHs preparation method.

(2) Replacing traditional stripping solvents such as formamide with water has the advantages of low cost, safety and environmental protection, and the aqueous solution of LDHs nanosheets formed by stripping has good stability.

(3) Make full use of the excellent electrical, mechanical, thermal conductivity, high carrier density and high carrier mobility properties of single-layer graphene oxide, and perform alternate layer-by-layer self-assembly with LDHs nanosheets to obtain a stacked The structured infrared nano-membrane material has the characteristics of good light transmission and low infrared emissivity.

Detailed ways

Example 1:

a) According to the molar ratio of DL-lactic acid to Fe powder is 8:1, add 0.5mol/L DL-lactic acid aqueous solution and Fe powder metal successively into the reaction kettle, react at room temperature for 10h, under _N2 atmosphere, Add 1.2mL of 30wt% H ₂ O ₂ aqueous solution to the above reaction solution per gram of Fe powder for oxidation reaction for 0.6h. The molar ratio of Co powder and Fe powder is 2:1, then add Co powder and react at room temperature for 10h. After the reaction, use 8mol/L NaOH aqueous solution to adjust pH to 9.5, hydrothermal crystallization at 80°C for 48h, cooling, filtering, washing with deionized water 4 times, according to the molar ratio of Fe powder and deionized water as 1:1000, disperse with deionized water, The suspension of LDHs intercalated with DL-lactate was obtained, and allowed to stand at 30° C. for 48 hours to obtain an aqueous solution of LDHs nanosheets.

b) Add 20mL of alkyd mixed solution per square centimeter of silicon wafer, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, immerse the silicon wafer in the alkyd mixed solution at room temperature for 0.5 h, wash 10 times with deionized water after taking it out, add 10mL 98wt% concentrated sulfuric acid per square centimeter silicon wafer, then immerse the silicon wafer in concentrated sulfuric acid for 0.5h, wash 10 times with deionized water after taking it out, Dry at room temperature for 2 minutes under _N2 atmosphere to obtain a modified silicon wafer.

c) Add 40 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of modified silicon wafer, soak the modified silicon wafer at room temperature for 5 min, take it out, wash it with deionized water 10 times, _and Dry at room temperature for 8 minutes in an atmosphere to obtain LDHs-assembled silicon wafers.

d) Add 40 mL of 1 mg/mL single-layer graphene oxide aqueous solution to each square centimeter of LDHs-assembled silicon wafer, soak the LDHs-assembled silicon wafer prepared in step c) at room temperature for 5 min, take it out, and wash it with deionized water for 10 The first step is to dry at room temperature for 8 minutes under _N2 atmosphere to obtain the self-assembled membrane material. The self-assembled membrane material is carried out 5 times according to the method of step c) and step d) with LDHs nanosheets and single-layer graphene oxide as the unit. Alternately self-assembled layer by layer to obtain a self-assembled laminated infrared film material. The film thickness of the material is 18nm, and the infrared emissivity of the material is 0.539 in the 8-14μm band at 25°C.

Example 2:

a) According to the molar ratio of oxalic acid and Co powder is 5:1, add 0.2mol/L oxalic acid aqueous solution and Co powder into the reaction kettle successively, and react at room temperature for 4 hours, under _N2 atmosphere, press Add 0.5mL 30wt% H ₂ O ₂ aqueous solution to each gram of Co powder for oxidation reaction for 0.8h. According to the molar ratio of Mn powder and Co powder is 2:1, then add Mn powder and react at room temperature for 4h. After the reaction, use 8mol/L KOH aqueous solution Adjust the pH to 10, hydrothermally crystallize at 90°C for 72 hours, cool, filter, and wash with deionized water for 6 times. According to the molar ratio of Co powder and deionized water as 1:2500, disperse with deionized water to obtain oxalate root intercalation The suspension of LDHs was allowed to stand at 25° C. for 36 hours to obtain an aqueous solution of LDHs nanosheets.

b) Add 20mL of alkyd mixed solution per square centimeter of quartz slice, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, immerse the quartz slice in the alkyd mixed solution at room temperature for 0.8h, take it out Wash 12 times with deionized water, add 10mL 98wt% concentrated sulfuric acid per square centimeter of quartz plate, then immerse the quartz plate in concentrated sulfuric acid for 0.8h, take it out, wash it with deionized water 12 times, and dry it at room temperature for 5min under _N2 atmosphere. A modified quartz plate was obtained.

c) Add 60 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of modified quartz sheet, soak the modified quartz sheet at room temperature for 8 min, take it out, wash it with deionized water for 7 times, and dry it at room temperature under _N2 atmosphere 3min, get LDHs assembly quartz plate.

d) Add 60 mL of 0.7 mg/mL single-layer graphene oxide aqueous solution per square centimeter of LDHs-assembled quartz plate, soak the LDHs-assembled quartz plate prepared in step c) at room temperature for 8 min, take it out, wash it with deionized water 7 times, and The self-assembled membrane material was obtained by drying at room temperature for 3 minutes under _N2 atmosphere. The self-assembled membrane material was subjected to 25 times of alternating layer-by-layer self-assembly with LDHs nanosheets and single-layer graphene oxide as the unit according to the method of step c) and step d. Assembled to obtain a self-assembled laminated infrared film material, the film thickness of the material is 103nm, and the infrared emissivity of the material is 0.385 in the 8-14μm band at 25°C.

Example 3:

a) According to the molar ratio of benzoic acid and (Co powder + Fe powder) is 10:1, wherein the molar ratio of Co powder and Fe powder is 1:4, 1.0mol/L aqueous solution of benzoic acid and (Co powder + Fe powder) powder) was successively added to the reaction kettle, and after reacting at room temperature for 8 hours, under N ₂ atmosphere, 5.0 mL of 30wt% H ₂ O ₂ aqueous solution was added to the above reaction solution per gram for oxidation reaction for 0.5 h, and Mg powder and (Co powder + Fe powder) metal molar ratio is 2:1, then add Mg powder and react at room temperature for 8 hours, after the reaction, use 8mol/L NaOH aqueous solution to adjust the pH to 10, hydrothermal crystallization at 75°C for 60 hours, cool, filter, and wash with deionized water 5 times, press the molar ratio of (Co powder + Fe powder) to deionized water to be 1:3000, disperse with deionized water to obtain a suspension of LDHs intercalated with benzoate radicals, and stand at 25°C for 36 hours to obtain LDHs nanosheets in aqueous solution.

b) Add 20mL of alkyd mixed solution per square centimeter of silicon wafer, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, and immerse the silicon wafer in the alkyd mixed solution for 1 hour at room temperature After taking it out, wash it 15 times with deionized water, add 10mL of 98wt% concentrated sulfuric acid per square centimeter of silicon wafer, then immerse the silicon wafer in concentrated sulfuric acid for 1h, wash it 15 times with deionized water after taking it out, and put it under N ₂ Dry at room temperature for 10 minutes under atmosphere to obtain a modified silicon wafer.

c) Add 100 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of the modified silicon wafer, soak the modified silicon wafer at room temperature for 11 min, take it out, wash it with deionized water 8 times, and place it under N ₂ Dry at room temperature for 6 minutes under atmosphere to obtain LDHs-assembled silicon wafers.

d) Add 100mL of 0.8mg/mL single-layer graphene oxide aqueous solution to each square centimeter of LDHs-assembled silicon wafer, soak the LDHs-assembled silicon wafer prepared in step c) at room temperature for 11min, take it out, and wash it with deionized water 8 times, dry at room temperature under _N2 atmosphere for 6min to obtain the self-assembled membrane material, the self-assembled membrane material is carried out 30 times according to the method of step c) and step d, using LDHs nanosheets and single-layer graphene oxide as the unit Alternately self-assembled layer by layer to obtain a self-assembled laminated infrared film material with a film thickness of 150nm and an infrared emissivity of 0.407 in the 8-14μm band at 25°C.

Example 4:

a) According to the molar ratio of acetic acid to Co powder is 6:1, add 0.8mol/L carboxylic acid aqueous solution and Co powder to the reaction kettle successively, and react at room temperature for 7 hours, and add to the above reaction solution under _N2 atmosphere Add 4.2mL 30wt% H ₂ O ₂ aqueous solution for oxidation reaction for 0.5h per gram of Co, according to the molar ratio of (Zn powder+Mn powder) to Co powder is 2:1, then add Zn powder and Mn powder and react at room temperature for 7h, After the reaction, use 8mol/L KOH aqueous solution to adjust the pH to 10.5, hydrothermal crystallization at 80°C for 72h, cool, filter, and wash with deionized water for 4 times. The molar ratio of Co powder to deionized water is 1:5000. Disperse with water to obtain a suspension of LDHs intercalated with benzoate radicals, and let stand at 20°C for 24 hours to obtain an aqueous solution of LDHs nanosheets.

b) Add 20mL of alkyd mixed solution per square centimeter of quartz slice, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, immerse the quartz slice in the alkyd mixed solution at room temperature for 0.5h, take it out Wash 10 times with deionized water, add 10mL 98wt% concentrated sulfuric acid per square centimeter of quartz plate, then immerse the substrate in concentrated sulfuric acid for 0.5h, take it out, wash 10 times with deionized water, and dry at room temperature for 3min under _N2 atmosphere , to obtain modified quartz slices.

c) Add 75 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of modified quartz sheet, soak the modified quartz sheet at room temperature for 15 min, take it out, wash it with deionized water for 5 times, and dry it at room temperature under _N2 atmosphere 4min, get LDHs assembly quartz plate.

d) Add 75 mL of 0.5 mg/mL single-layer graphene oxide aqueous solution to each square centimeter of LDHs-assembled quartz plate, soak the LDHs-assembled quartz plate prepared in step c) at room temperature for 15 min, take it out, wash it with deionized water 5 times, and Dry at room temperature for 4 minutes under N _atmosphere to obtain the self-assembled membrane material. According to the method of step c) and step d, the self-assembled membrane material is subjected to 40 times of alternating layer-by-layer self-assembly with LDHs nanosheets and single-layer graphene oxide as the unit. Assembled to obtain a self-assembled laminated infrared film material with a film thickness of 200nm and an infrared emissivity of 0.512 at 25°C in the 8-14μm band.

Example 5:

a) According to the molar ratio of formic acid to Fe powder is 7:1, add 0.3mol/L carboxylic acid aqueous solution and Fe powder into the reaction kettle successively, and react at room temperature for 4 hours, and add to the above reaction solution under _N2 atmosphere Add 1.4mL of 30wt% H ₂ O ₂ aqueous solution per gram of Fe powder for oxidation reaction for 0.9h, according to the molar ratio of (Mg powder+Co powder+Mn powder) to Fe powder is 2:1, then add (Mg powder+Co powder + Mn powder) at room temperature for 4~10 hours, after the reaction, use 8mol/L NaOH aqueous solution to adjust the pH to 10, hydrothermal crystallization at 82°C for 50 hours, cool, filter, and wash with deionized water for 5 times, according to the ratio of Fe powder and deionized water The molar ratio was 1:1500, dispersed with deionized water to obtain a suspension of formate-intercalated LDHs, and left to stand at 28°C for 40 hours to obtain an aqueous solution of LDHs nanosheets.

b) Add 20mL of alkyd mixed solution per square centimeter of quartz plate, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, immerse the substrate in the alkyd mixed solution at room temperature for 0.9h, take it out Wash 14 times with deionized water, add 10mL of 98wt% concentrated sulfuric acid per square centimeter of quartz plate, then immerse the quartz plate in concentrated sulfuric acid for 0.9h, take it out, wash it with deionized water 14 times, and dry it at room temperature for 5min under N2 atmosphere to obtain Modified quartz flakes.

c) Add 85 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of modified quartz sheet, soak the modified quartz sheet at room temperature for 6 min, take it out, wash it with deionized water for 10 times, and dry it at room temperature under _N2 atmosphere 2min, get LDHs assembly quartz plate.

d) Add 85 mL of 0.9 mg/mL single-layer graphene oxide aqueous solution to each square centimeter of LDHs-assembled quartz plate, soak the LDHs-assembled quartz plate prepared in step c) at room temperature for 6 minutes, take it out, wash it with deionized water for 10 times, and Dry at room temperature for 2 minutes under _N2 atmosphere to obtain the self-assembled membrane material. The self-assembled membrane material is subjected to 20 alternate layers of LDHs nanosheets and single-layer graphene oxide according to the method of step c) and step d). Self-assembled to obtain a self-assembled laminated infrared film material, the film thickness of which is 96nm, and the infrared emissivity of the material is 0.396 in the 8-14μm band at 25°C.

Embodiment 6:

a) According to the molar ratio of L-(+)-tartaric acid and (Co powder + Fe powder) is 9:1, add 0.6mol/L L-(+)-tartaric acid aqueous solution and (Co powder + Fe powder) successively After 4 hours of reaction at room temperature, add 3.5mL of 30wt% _H2O2 aqueous solution to the above reaction solution per gram of (Co powder + Fe powder) for oxidation reaction for 0.6h under _{N2 atmosphere} . powder + Co powder + Mn powder + Zn powder) to (Co powder + Fe powder) in a molar ratio of 2:1, then add (Mg powder + Co powder + Mn powder + Zn powder) to react at room temperature for 10 hours, and then use 8mol /L NaOH aqueous solution to adjust the pH to 10.5, hydrothermal crystallization at 70°C for 72 hours, cooling, filtering, and deionized water washing 6 times, according to the molar ratio of (Co powder + Fe powder) to deionized water 1:4500, use Ionized water was dispersed to obtain a suspension of LDHs intercalated with L-(+)-tartrate groups, and left to stand at 22°C for 30 hours to obtain an aqueous solution of LDHs nanosheets.

b) Add 20mL of alkyd mixed solution per square centimeter of silicon wafer, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, immerse the silicon wafer in the alkyd mixed solution at room temperature for 0.6 h, take it out and wash it 13 times with deionized water, add 10mL of 98wt% concentrated sulfuric acid per square centimeter of silicon wafer, then immerse the silicon wafer in concentrated sulfuric acid for 0.6h, take it out and wash it 13 times with deionization, Dry at room temperature for 6 minutes under _N2 atmosphere to obtain a modified silicon wafer.

c) Add 90 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of modified silicon wafer, soak the modified silicon wafer at room temperature for 14 min, take it out, wash it with deionized water 8 times, _and Dry at room temperature for 6 minutes under atmosphere to obtain LDHs-assembled silicon wafers.

d) Add 90mL 0.6~1mg/mL single-layer graphene oxide aqueous solution to each square centimeter of LDHs-assembled silicon wafer, soak the LDHs-assembled silicon wafer prepared in step c) at room temperature for 14min, take it out, and rinse with deionized water Wash 8 times, and dry at room temperature for 6 minutes under _N2 atmosphere to obtain a self-assembled membrane material. The self-assembled membrane material is processed according to the method of step c) and step d) with LDHs nanosheets and single-layer graphene oxide as the unit. 10 times of alternating layer-by-layer self-assembly, the self-assembled laminated infrared film material was obtained. The film thickness of the material was 37nm, and the infrared emissivity of the material was 0.493 in the 8-14μm band at 25°C.

Embodiment 7:

a) According to the molar ratio of propionic acid to (Co powder + Fe powder) is 10:1, add 1.0mol/L carboxylic acid aqueous solution and (Co powder + Fe powder) into the reactor successively, and react at room temperature for 8 hours, Under N ₂ atmosphere, add 4.8mL of 30wt% H ₂ O ₂ aqueous solution to the above reaction solution for each gram of (Co powder + Fe powder) and oxidize it for 0.7h. Fe powder) with a molar ratio of 2:1, then add (Mg powder + Zn powder) to react at room temperature for 8 hours, after the reaction, adjust the pH to 9.5 with 8mol/L KOH aqueous solution, hydrothermally crystallize at 80°C for 55 hours, cool, filter, and remove Wash with deionized water for 6 times, press the molar ratio of (Co powder + Fe powder) to deionized water to be 1:2000, disperse with deionized water to obtain a suspension of carboxylate intercalated LDHs, and let it stand at 26°C for 45h , to obtain LDHs nanosheet aqueous solution.

b) Add 20mL of alkyd mixture per square centimeter of quartz plate, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixture is 1:1, immerse the substrate in the alkyd mixture at room temperature for 0.5h, take it out Wash 10 times with deionized water, add 10mL 98wt% concentrated sulfuric acid per square centimeter of quartz plate, then immerse the quartz plate in concentrated sulfuric acid for 0.5h, take it out, wash it with deionized water 10 times, and dry it at room temperature under _N2 atmosphere for 7min, A modified quartz plate was obtained.

c) Add 55 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of modified quartz sheet, soak the modified quartz sheet at room temperature for 15 minutes, take it out, wash it with deionized water 10 times, and dry it at room temperature under _N2 atmosphere 8min, get LDHs assembly quartz plate.

d) Add 55 mL of 0.7 mg/mL single-layer graphene oxide aqueous solution to each square centimeter of LDHs-assembled quartz plate, soak the LDHs-assembled quartz plate prepared in step c) at room temperature for 15 min, take it out, wash it with deionized water for 10 times, and Dry at room temperature for 8 minutes under _N2 atmosphere to obtain the self-assembled membrane material. According to the method of step c) and step d), the self-assembled membrane material is alternately layered 35 times with LDHs nanosheets and single-layer graphene oxide as the unit. Self-assembled to obtain a self-assembled laminated infrared film material, the film thickness of which is 162nm, and the infrared emissivity of the material is 0.475 in the 8-14μm band at 25°C.

Claims (4)

1. A self-assembled laminated infrared film material, characterized in that the material is self-assembled by alternating layers of layered double hydroxide LDHs nanosheets and single-layer graphene oxide, with LDHs nanosheets The layer structure is sequentially stacked with a single layer of graphene oxide, the number of layers is 2~40, and the thickness of the infrared film material is 2~200nm. 2. A kind of self-assembled laminated infrared film material according to claim 1, it is characterized in that the laminate metal ion of described LDHs nanoplate is made up of M ₁ metal ion and M ₂ metal ion, wherein M ₁ metal ion and The molar ratio of M ₂ metal ions is 2:1, M ₁ metal ions are one or more combinations of Mg ²⁺ , Co ²⁺ , Mn ²⁺ , Zn ²⁺ , and M ₂ metal ions are Fe ³⁺ , Co ³⁺ or a combination of both. 3. a preparation method of self-assembled laminated infrared film material as claimed in claim 1, is characterized in that its preparation method is: a) According to the molar ratio of carboxylic acid to _M2 metal is 5~10:1, add 0.2~1.0mol/L carboxylic acid aqueous solution and _M2 metal into the reaction kettle successively, react at room temperature for 4~10h, and then ₂ atmosphere, add 0.5~ _5.0mL 30wt% _H2O2 aqueous solution to the above reaction solution per gram of M2 metal for oxidation _reaction for 0.5~1h, and the molar ratio of _M1 metal to _M2 metal is 2:1, Then add _M1 metal and react at room temperature for 4~10h. After the reaction, use 8mol/L inorganic alkali aqueous solution to adjust the pH to 9.5~10.5, hydrothermal crystallization at 70~90℃ for 48~72h, cool, filter, and wash with deionized water for 4~6 Second, according to the molar ratio of _M2 metal to deionized water as 1:1000~5000, disperse with deionized water to obtain a suspension of carboxylate intercalated LDHs, and let it stand at 20~30°C for 24~48h to obtain LDHs nanosheet aqueous solution; b) Add 20mL of alkyd mixed solution per square centimeter of substrate, the substrate is silicon wafer or quartz sheet, the volume ratio of methanol to 37.5wt% concentrated hydrochloric acid in the alkyd mixed solution is 1:1, and the substrate is placed at room temperature Immerse in the alkyd mixed solution for 0.5~1h, take it out and wash it with deionized water for 10~15 times, add 10mL98wt% concentrated sulfuric acid per square centimeter substrate, then immerse the substrate in concentrated sulfuric acid for 0.5~1h, take it out and use it Wash with deionized water for 10-15 times, and dry at room temperature for 2-10 minutes under _N2 atmosphere to obtain the modified substrate; c) Add 40-100 mL of the LDHs nanosheet aqueous solution prepared in step a) per square centimeter of the modified substrate, soak the modified substrate at room temperature for 5-15 minutes, take it out, wash it with deionized water 5-10 times, and Dry at room temperature for 2-8 minutes under _N2 atmosphere to obtain LDHs assembly substrate; d) Add 40~100mL 0.5~1mg/mL single-layer graphene oxide aqueous solution per square centimeter of LDHs assembly substrate, soak the LDHs assembly substrate prepared in step c) at room temperature for 5~15min, take it out, and rinse with deionized water Wash 5 to 10 times, and dry at room temperature for 2 to 8 minutes under _N2 atmosphere to obtain a self-assembled membrane material. The self-assembled membrane material is prepared by the method of step c) and step d) with LDHs nanosheets and single-layer graphene oxide Carry out 2~40 times of alternating layer-by-layer self-assembly for the primitive, and obtain the self-assembled laminated infrared film material. 4. A method for preparing a self-assembled laminated infrared film material according to claim 2, characterized in that the carboxylic acid described in step a) of the preparation method is formic acid, acetic acid, propionic acid, oxalic acid, DL-lactic acid , L-lactic acid, benzoic acid, salicylic acid, L-(+)-tartaric acid, D-(-)-tartaric acid, DL-tartaric acid, the inorganic base is NaOH or KOH.