CN113060734A - Infrared low-emissivity MXene film and preparation method thereof - Google Patents

Abstract

The invention relates to the field of functional materials, in particular to an infrared low-emissivity MXene film for infrared stealth and thermal camouflage and a preparation method thereof. A preparation method of an infrared low-emissivity MXene film comprises the following steps: pouring the MXene solution into a filter flask with a filter membrane, and uniformly loading the MXene on the surface of the filter membrane through vacuum filtration to form an MXene thin layer on the surface of the filter membrane; and then separating the dried MXene thin layer from the filter membrane to obtain the MXene film. The emissivity of the MXene film prepared by the method is 0.05-0.5 in an infrared band of 7-14 um; the preparation method has the advantages of stable reaction, simplicity, easy operation, safe, convenient and environment-friendly process and good uniformity of the obtained product; the raw materials have wide sources, can be used in large scale and are beneficial to popularization.

Description

Infrared low-emissivity MXene film and preparation method thereof

Technical Field

The invention relates to the field of functional materials, in particular to an infrared low-emissivity MXene film used in the field of infrared stealth and thermal camouflage and a preparation method thereof.

Background

With the rapid development of electronic countermeasure technology, acquisition and reverse acquisition of information have been focused. Infrared detection is one of the technologies mainly used therein. The infrared stealth technology is an important reconnaissance and anti-reconnaissance means, and the application of the infrared stealth technology can reduce the possibility that a target is reconnaissance and found by a thermal infrared imager, so that the exposure can be effectively prevented. The application and development of low infrared radiation materials promote the realization of infrared stealth.

The infrared detector collects infrared signals of the target in wave bands of 3-5 um and 7-14 um, and the target is identified through imaging by utilizing infrared radiation energy difference between the target and the background. According to Stefan-Boltzmann law, the infrared radiation energy W of an object is ∈ t⁴(where ε is the infrared emissivity of the surface of the object, σ is the Boltzmann constant, and T is the thermodynamic temperature of the surface of the object). Thus, technical approaches to achieving infrared stealth include reducing the infrared emissivity of the object and reducing the surface temperature of the object.

Reducing the infrared emissivity of the surface of an object is one of the most important methods for thermal infrared stealth at present. Good metal conductors (such as Al, Cu, Ag and the like) have high infrared reflectivity and low infrared emissivity, are suitable for being used as fillers in infrared stealth materials, and mainly adopt Al powder and Cu powder which are excellent in performance, cheap and easy to obtain in practical application. In addition, factors such as particle size, morphology and form of the metal filler play an important role in reducing the infrared emissivity of the infrared stealth coating. However, the high gloss and easy oxidation properties of the metal filler are detrimental to the durability, and the metal product has a high density and is difficult to mold.

Journal of Solid State Chemistry,2004,177(10):3849-₃The particles are used as raw materials to prepare polyimide/BaTiO₃Nanocomposite films of BaTiO₃When the addition amount is 14.7 percent (w), the lowest emissivity of the film in a wave band of 8-14 mu m can reach 0.574.

Professor Yury gootsi of dare university, usa, found that MXene materials, i.e. two-dimensional transition metal carbides/nitrides/carbonitrides, could be prepared by wet chemical etching of the MAX phase. MXene, a novel two-dimensional crystal material, can be represented by the chemical formula M_n+1X_nT_xWherein M is a transition metal, X is carbon or nitrogen, and T represents a surface group (═ O, -OH, -F). MXene surface groups are adjustable, conductivity is excellent, and the MXene surface groups can be used for energy storage and electromagnetic shielding; meanwhile, MXene has nearly one hundred percent of photo-thermal conversion efficiency.

Currently, the study of MXene materials mainly focuses on electromagnetic shielding, but no report about MXene infrared emission performance exists. Therefore, the development of the MXene material with low infrared emissivity has important significance and application value for promoting the development of infrared stealth and thermal camouflage materials.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention aims to provide an infrared low-emissivity MXene film used in the field of infrared stealth and thermal camouflage and a preparation method thereof.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

a preparation method of an infrared low-emissivity MXene film comprises the following steps:

pouring the MXene solution into a filter flask with a filter membrane, and uniformly loading the MXene on the surface of the filter membrane through vacuum filtration to form an MXene thin layer on the surface of the filter membrane; and then separating the dried MXene thin layer from the filter membrane to obtain the MXene film.

Preferably, the concentration of the MXene solution is 0.1-25 mg/mL.

Preferably, the thickness of the MXene film is 0.1-100 um, and the emissivity of the MXene film in an infrared band of 7-14 um is 0.05-0.5.

Preferably, the MXene film is annealed in vacuum or air or oxygen or inert gas at the temperature of 20-500 ℃ to prepare the annealed and modified MXene film.

Preferably MXene is Ti₃C₂T_x、Ti₂CT_x、Ti₃CNT_x、Nb₂CT_x、V₂CT_xAt least one of the following solutions is adoptedThe preparation method comprises the following steps:

(1) dissolving 1-100 g LiF in 20-2000 mL of 5-12 mol/L HCl solution to prepare etching solution; at 35-40 deg.C, adding 1-100 g Ti₃AlC₂Adding the Ti powder into the etching solution for etching for 18-36 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH value is 6-7, pouring out the supernatant to obtain Ti₃C₂T_xPrecipitating; mixing the above Ti₃C₂T_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti₃C₂T_xA solution;

(2) uniformly mixing 12-1200 mL of 5-12 mol/L HCL solution, 2-200 mL of 15-30 mol/L HF solution and 6-600 mL of deionized water to prepare etching solution; at room temperature, adding 1-100 g Ti₂Adding AlC into the etching solution for etching for 18-36 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH value is 6-7, pouring out the supernatant to obtain Ti₂CT_xPrecipitating; mixing the above Ti₂CT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti₂CT_xA solution;

(3) dissolving 1-100 g LiF in 20-2000 mL of 5-12 mol/L HCl solution to prepare etching solution; at 25-40 deg.C, adding 1-100 g Ti₃Adding AlCN into the etching solution for etching for 18-36 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH value is 6-7, pouring out the supernatant to obtain Ti₃CNT_xPrecipitating; mixing the above Ti₃CNT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti₃CNT_xA solution;

(4) at 35-40 deg.C, adding 1-100 g Nb₂Adding AlC into 20-2000 mL of 15-30 mol/L hydrofluoric acid etching solution for etching for 48-72 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH value is 6-7, and pouring out the supernatant to obtain Nb₂CT_xPrecipitating; mixing the above Nb₂CT_xAdding the precipitate into 50-3000 mL of deionized water and shaking, 3Centrifuging at the rotating speed of 500-5000 rpm, and collecting supernatant to obtain Nb₂CT_xA solution;

(5) at 35-40 deg.C, mixing 1-100 g V₂Adding AlC into 20-2000 mL of 15-30 mol/L hydrofluoric acid etching solution for etching for 48-72 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH value is 6-7, and pouring out the supernatant to obtain V₂CT_xPrecipitating; the above V is mixed₂CT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain V₂CT_xAnd (3) solution.

Preferably, the MXene solution is prepared by the following steps: freeze-drying MXene precipitate at-40 deg.C and <10pa to obtain MXene powder; and stirring the MXene powder, alkyl chain acyl chloride and triethylamine, mixing and stirring DMF, washing with absolute ethyl alcohol, centrifuging until the pH value is 6-7, and adding deionized water for ultrasonic treatment to obtain an alkyl chain modified MXene solution.

Preferably, the MXene solution is prepared by the following steps: freeze-drying MXene precipitate at-40 deg.C and <10pa to obtain MXene powder; and mixing the MXene powder with an alkali solution or an acid solution, washing with deionized water, centrifuging until the pH value is 6-8, and adding deionized water for ultrasonic treatment to obtain the alkali-modified or acid-modified MXene solution.

Preferably, the MXene solution is prepared by the following steps: freeze-drying MXene precipitate at-40 deg.C and <10pa to obtain MXene powder; mixing MXene powder, a silane coupling agent and an ethanol solution, cleaning with ethanol, centrifuging, and removing unreacted silane coupling agent to obtain suspension, namely the MXene solution modified by the silane coupling agent.

The MXene film prepared by the preparation method of the MXene film with the low infrared emissivity.

An application of an infrared low-emissivity MXene film is applied to the field of infrared stealth and thermal camouflage.

(III) advantageous effects

The invention provides an MXene film with low infrared emissivity and a preparation method thereof, and the MXene film has the following beneficial effects:

the emissivity of the MXene film/modified MXene film prepared by the method is 0.05-0.5 in the infrared band range of 7-14 um; the preparation method has the advantages of stable reaction, simplicity, easy operation, safe, convenient and environment-friendly process and good uniformity of the obtained product; the raw materials have wide sources, can be used in large scale and are beneficial to popularization.

Drawings

FIG. 1 is a schematic representation of MXene films prepared in example 1 and their thickness and curvature;

FIG. 2 is a graph of the infrared camouflage and thermal camouflage effect of the MXene film prepared in example 1;

fig. 3 is a graph of the infrared camouflage and thermal camouflage effect of the MXene film prepared in example 2;

FIG. 4 is a graph showing the infrared stealth and thermal camouflage effect of the MXene film annealed at 200 ℃ under vacuum in example 3;

FIG. 5 is a graph showing the infrared stealth and thermal camouflage effect of the MXene film annealed at 500 ℃ in an air atmosphere in example 4;

FIG. 6 is a graph showing the infrared stealth and thermal camouflage effect of the MXene film modified with octadecanoyl chloride in example 5;

FIG. 7 is a diagram showing the infrared stealth and thermal camouflage effect of the MXene film modified by the NaOH solution in example 6;

FIG. 8 is a graph showing the comparison of the infrared stealth effect and the thermal camouflage effect of the MXene film/modified MXene film in examples 1 to 10 on a 120 ℃ hot stage;

FIG. 9 is a spectrum of infrared emissivity of 7-14 um of the low infrared emissivity film of example 1;

fig. 10 is a graph of the infrared camouflage and thermal camouflage effect of the MXene film prepared in example 11;

fig. 11 is a graph of the infrared camouflage and thermal camouflage effect of the MXene film prepared in example 12;

fig. 12 is a graph of the infrared camouflage and thermal camouflage effect of the MXene film prepared in example 13;

fig. 13 is a graph of the infrared camouflage and thermal camouflage effect of the MXene film prepared in example 14;

FIG. 14 is a spectrum of infrared emissivity of the stainless steel film of 7-14 um.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Example 1

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

(1) adding 10g LiF into 200mL of 12mol/L HCl solution, and magnetically stirring in a water bath for 30min until the LiF is completely dissolved to prepare etching solution; at 35 ℃, 10g of Ti₃AlC₂Adding into etching solution, stirring for 24 hr, washing with deionized water, centrifuging at 3500rpm for 5min until pH reaches 6, and removing supernatant to obtain Ti₃C₂T_xPrecipitating;

(2) mixing the above Ti₃C₂T_xAdding 200mL deionized water into the precipitate, shaking for 7min, centrifuging at 3500rpm for 5min, and collecting supernatant to obtain Ti with concentration of 3mg/mL₃C₂T_xA solution;

(3) mixing 30mL of Ti₃C₂T_xPouring the solution into a filtration bottle with a cellulose acetate filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the titanium-containing solution on the surface of a cellulose acetate filter membrane and forming Ti on the surface of the filter membrane₃C₂T_xA thin layer, and then drying the Ti₃C₂T_xSeparating the thin layer from the filter membrane to obtain Ti₃C₂T_xA film.

Example 2

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 1, Ti was obtained₃C₂T_xA solution; adding 1mL of Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the Ti on the surface of the filter membrane to form Ti on the surface of the filter membrane₃C₂T_xA thin layer of a material selected from the group consisting of,then, drying the Ti₃C₂T_xSeparating the thin layer from the filter membrane to obtain Ti₃C₂T_xA film.

Example 3

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 1, Ti was obtained₃C₂T_xA solution; mixing 6mL of Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the Ti on the surface of the filter membrane to form Ti on the surface of the filter membrane₃C₂T_xA thin layer, and then drying the Ti₃C₂T_xSeparating the thin layer from the filter membrane to obtain Ti₃C₂T_xA film; mixing Ti₃C₂T_xAnnealing the film for 2h under the vacuum condition of 200 ℃ to prepare the annealing modified Ti₃C₂T_xA film.

Example 4

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 1, Ti was obtained₃C₂T_xA solution; 18mL of Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the Ti on the surface of the filter membrane to form Ti on the surface of the filter membrane₃C₂T_xA thin layer, and then drying the Ti₃C₂T_xSeparating the thin layer from the filter membrane to obtain Ti₃C₂T_xA film; adding the Ti₃C₂T_xAnnealing the film for 2h in the air atmosphere at 500 ℃ to prepare the annealing modified Ti₃C₂T_xA film.

Example 5

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 1, Ti was obtained₃C₂T_xA solution; 20mL of Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the Ti on the surface of the filter membrane to form Ti on the surface of the filter membrane₃C₂T_xA thin layer, and then drying the Ti₃C₂T_xSeparating the thin layer from the filter membrane to obtain Ti₃C₂T_xA film; adding the Ti₃C₂T_xAnnealing the film for 1h in a nitrogen atmosphere at 100 ℃ to prepare the annealing modified Ti₃C₂T_xA film.

Example 6

A preparation method of an infrared low-emissivity MXene film comprises the following steps:

with reference to example 1, Ti was obtained₃C₂T_xA solution; 22mL of Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the Ti on the surface of the filter membrane to form Ti on the surface of the filter membrane₃C₂T_xA thin layer, and then drying the Ti₃C₂T_xSeparating the thin layer from the filter membrane to obtain Ti₃C₂T_xA film; adding the Ti₃C₂T_xAnnealing the film for 4 hours in an oxygen atmosphere at 300 ℃ to prepare the annealing modified Ti₃C₂T_xA film.

Example 7

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 1, Ti was prepared₃C₂T_xPrecipitating; mixing Ti₃C₂T_xPrecipitating at-40 deg.C<Freeze drying under 10pa to obtain dried Ti₃C₂T_xPowder; at 60 ℃, 1g of Ti₃C₂T_xDissolving the powder in 250mL of DMF, adding 0.8g of octadecanoyl chloride and 0.5g of triethylamine, and magnetically stirring for 18 h; washing the reaction solution with anhydrous ethanol, and separating at 3500rpmHeating for 5min until pH reaches 6, adding deionized water, and performing ultrasonic treatment for 10min to obtain octadecane-modified Ti with concentration of 3.8mg/mL₃C₂T_xA solution; 40mL of the above-mentioned octadecane-modified Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and vacuum filtering to obtain Ti modified by octadecane₃C₂T_xUniformly loading the titanium oxide on a filter membrane to obtain the octadecane modified Ti₃C₂T_xA film.

Example 8

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 7, Ti was obtained₃C₂T_xPowder; at 35 ℃, 0.5g of Ti₃C₂T_xDissolving the powder in 500mL of 0.1mol/L NaOH solution and stirring for 6 h; washing the reaction solution with deionized water, centrifuging at 3500rpm for 5min until pH reaches 8, adding deionized water, and performing ultrasonic treatment for 5min to obtain NaOH-modified Ti with concentration of 3mg/mL₃C₂T_xA solution; 50mL of NaOH modified Ti₃C₂T_xPouring the solution into a filter flask with a filter membrane, and carrying out vacuum filtration to obtain Ti modified by NaOH₃C₂T_xUniformly loading the mixture on the surface of a filter membrane to obtain the product with Na on the surface⁺Ti of (A)₃C₂T_xA film.

Example 9

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 7, Ti was obtained₃C₂T_xPowder; at 35 ℃, 1g of Ti₃C₂T_xThe powder was dissolved in 100mL of 1mol/L H₂SO₄Stirring the solution for 6 hours; washing the reaction solution with deionized water, centrifuging at 3500rpm for 5min until pH reaches 6, adding deionized water, and performing ultrasonic treatment for 5min to obtain sulfuric acid modified Ti with concentration of 4.7mg/mL₃C₂T_xA solution; 30mL of sulfuric acid-modified Ti₃C₂T_xThe solution is poured into a filtration flask containing a filter membrane and passed throughVacuum filtering to modify Ti with sulfuric acid₃C₂T_xUniformly loading the mixture on the surface of the filter membrane to obtain the membrane with SO on the surface₄ ^2-Ti of (A)₃C₂T_xA film.

Example 10

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

with reference to example 7, Ti was obtained₃C₂T_xPowder; mixing 1g of Ti₃C₂T_xAdding powder and 2g AEAPTMS (aminopropyl trimethoxy silane) into ethanol solution and stirring for 2 h; washing the reaction solution with ethanol, centrifuging at 3500rpm, removing unreacted AEAPTMS, and collecting suspension, i.e. Ti modified by silane coupling agent with concentration of 4.3mg/mL₃C₂T_xA solution; 60mL of silane coupling agent-modified Ti₃C₂T_xPouring the suspension into a filter flask with a polypropylene membrane, and performing vacuum filtration to obtain AEAPTMS modified Ti₃C₂T_xA film.

Example 11

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

(1) uniformly mixing 12mL of 12mol/L HCL solution, 2mL of 28mol/L HF solution and 6mL of deionized water to prepare etching solution; at room temperature, add 1g of Ti₂Adding AlC into the etching solution for etching for 36h, cleaning with deionized water, centrifuging at 4000rpm until the pH is 6, and removing the supernatant to obtain Ti₂CT_xPrecipitating;

(2) mixing the above Ti₂CT_xAdding 200mL deionized water into the precipitate, shaking for 7min, centrifuging at 3500rpm for 5min, and collecting supernatant to obtain Ti with concentration of 2.8mg/mL₃C₂T_xA solution;

(3) adding 1mL of Ti₂CT_xPouring the solution into a filtration bottle with a cellulose acetate filter membrane, and vacuum filtering to obtain Ti₃C₂T_xUniformly loading the titanium-containing solution on the surface of a cellulose acetate filter membrane and forming Ti on the surface of the filter membrane₂CT_xA thin layer, and then drying the Ti₂CT_xSeparating the thin layer from the filter membrane to obtain Ti₂CT_xA film.

Example 12

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

(1) dissolving 5g LiF in 100mL of 12mol/L HCl solution to prepare etching solution; at 30 ℃, add 5g of Ti₃Adding AlCN into the etching solution for etching for 18h, cleaning with deionized water, centrifuging at 3500rpm until pH is 6, and removing supernatant to obtain Ti₃CNT_xPrecipitating;

(2) mixing the above Ti₃CNT_xAdding the precipitate into 150mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti with the concentration of 3.5mg/mL₃CNT_xA solution;

(3) 2mL of Ti₃CNT_xPouring the solution into a filtration bottle with a cellulose acetate filter membrane, and vacuum filtering to obtain Ti₃CNT_xUniformly loading the titanium-containing solution on the surface of a cellulose acetate filter membrane and forming Ti on the surface of the filter membrane₃CNT_xA thin layer, and then drying the Ti₃CNT_xSeparating the thin layer from the filter membrane to obtain Ti₃CNT_xA film.

Example 13

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

(1) at 35 ℃, 1g of Nb₂Adding AlC into 20mL of 28mol/L hydrofluoric acid etching solution for etching for 48h, cleaning with deionized water, centrifuging at the rotating speed of 3500rpm until the pH value is 6, pouring out the supernatant to obtain Nb₂CT_xPrecipitating;

(2) mixing the above Nb₂Adding the CTx precipitate into 100mL deionized water, oscillating, centrifuging at 3500rpm, and collecting the supernatant to obtain Nb with concentration of 4mg/mL₂CT_xAnd (3) solution.

(3) 4mL of Nb₂The CTx solution is poured into a filter flask with a cellulose acetate filter membrane, and Nb is filtered by vacuum filtration₂CTx was uniformly loaded on cellulose acetateForming Nb on the surface of the filter membrane₂CT_xA thin layer, and then drying the Nb₂CT_xSeparating the thin layer from the filter membrane to obtain Nb₂CT_xA film.

Example 14

An infrared low-emissivity MXene film and a preparation method thereof comprise the following steps:

(1) at 40 ℃, 1g V₂Adding AlC into 20mL of 25mol/L hydrofluoric acid etching solution for etching for 60h, cleaning with deionized water, centrifuging at 3500rpm until the pH value is 6, and pouring out the supernatant to obtain V₂CT_xPrecipitating;

(2) the above V is mixed₂CT_xAdding the precipitate into 100mL deionized water, shaking, centrifuging at 3500rpm, and collecting supernatant to obtain the final product with concentration of 3.8mg/mL V₂CT_xA solution;

(3) will be 6mLV₂CT_xPouring the solution into a filtration bottle with a cellulose acetate filter membrane, and vacuum filtering to obtain V₂CT_xUniformly loaded on the surface of a cellulose acetate filter membrane and form V on the surface of the filter membrane₂CT_xThin layer, then drying the V₂CT_xSeparating the thin layer from the filter membrane to obtain V₂CT_xA film.

Testing and analysis

(1) Bending effect of MXene film

As shown in fig. 1, the thickness of the MXene film obtained in example 1 of the present invention is 29um, and the MXene film can be folded in half without any damage, which shows that the MXene film has a good bending effect.

(2) Thermal camouflage effect testing and analysis

The MXene film prepared in the above example was covered on the surface of a hot stage by an infrared thermal imager model FLIR E75, and the infrared stealth and thermal camouflage effects of the MXene film were observed by comparing the temperature difference between the film and the hot stage in the infrared photograph. As shown in fig. 3 to 8, compared with the pure MXene film, the MXene film annealed in the inert gas and the vacuum has a reduced surface functional group, so that the thermal camouflage effect is improved; compared with pure MXene films, the MXene films subjected to annealing treatment in the air and oxygen atmosphere and the MXene films subjected to surface modification by alkyl chain acyl chloride, sulfuric acid, sodium hydroxide and a silane coupling agent have different degrees of reduction in thermal camouflage effect.

The MXene films of different modification methods can be selected according to the actual temperature of the target object and different required thermal camouflage degrees so as to further regulate and control the temperature of the object in the infrared camera.

(3) Infrared emissivity testing and analysis

The infrared emissivity of the MXene film/modified MXene film prepared in the above examples was measured, and the results are shown in Table 1.

TABLE 1 Infrared emissivity of different MXene films

As can be seen from fig. 2 to 14 and table 1, the infrared emissivity of the modified MXene thin film obtained in example 1 and the modified MXene thin film obtained in examples 2 to 9 after different surface modifications is smaller than that of the polyimide/BaTiO thin film obtained in the background art₃The infrared emissivity of the nano composite film is close to or less than that of the stainless steel film.

In conclusion, the pure MXene film and the MXene film subjected to surface modification by different methods are both infrared low-emissivity films, and have good thermal camouflage effect.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (10)

1. The preparation method of the MXene film with low infrared emissivity is characterized by comprising the following steps:

pouring the MXene solution into a filter flask with a filter membrane, and uniformly loading the MXene on the surface of the filter membrane through vacuum filtration to form an MXene thin layer on the surface of the filter membrane; and then separating the dried MXene thin layer from the filter membrane to obtain the MXene film.

2. The method for preparing the MXene film with low infrared emissivity as claimed in claim 1, wherein the concentration of the MXene solution is 0.1-25 mg/mL.

3. The method for preparing the MXene thin film with low infrared emissivity as claimed in claim 1, wherein the thickness of the MXene thin film is 0.1-100 um, and the emissivity of the MXene thin film in the infrared band of 7-14 um is 0.05-0.5.

4. The method for preparing the MXene thin film with low infrared emissivity as claimed in claim 1, wherein the MXene thin film is annealed in vacuum or air or oxygen or inert gas at 20-500 ℃ to obtain the annealed and modified MXene thin film.

5. The method for preparing the MXene film with low infrared emissivity as claimed in any one of claims 1 to 4, wherein the MXene is Ti₃C₂T_x、Ti₂CT_x、Ti₃CNT_x、Nb₂CT_x、V₂CT_xThe solution is prepared by the following steps:

dissolving 1-100 g LiF in 20-2000 mL of 5-12 mol/L HCl solution to prepare etching solution; at 35-40 deg.C, adding 1-100 g Ti₃AlC₂Adding the Ti powder into the etching solution for etching for 18-36 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH is = 6-7, and pouring out the supernatant to obtain Ti₃C₂T_xPrecipitating; mixing the above Ti₃C₂T_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti₃C₂T_xA solution;

mixing 12-1200 mL of 5-12 mol/L HCL solution and 2-200 mLUniformly mixing 15-30 mol/L HF solution and 6-600 mL deionized water to prepare etching solution; at room temperature, adding 1-100 g Ti₂Adding AlC into the etching solution for etching for 18-36 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH is = 6-7, pouring out the supernatant to obtain Ti₂CT_xPrecipitating; mixing the above Ti₂CT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti₂CT_xA solution;

dissolving 1-100 g LiF in 20-2000 mL of 5-12 mol/L HCl solution to prepare etching solution; at 25-40 deg.C, adding 1-100 g Ti₃Adding AlCN into the etching solution for etching for 18-36 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH is = 6-7, pouring out the supernatant to obtain Ti₃CNT_xPrecipitating; mixing the above Ti₃CNT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Ti₃CNT_xA solution;

at 35-40 deg.C, adding 1-100 g Nb₂Adding 20-2000 mL of 15-30 mol/L hydrofluoric acid etching solution into AlC for etching for 48-72 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH is = 6-7, pouring out the supernatant to obtain Nb₂CT_xPrecipitating; mixing the above Nb₂CT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain Nb₂CT_xA solution;

at 35-40 deg.C, mixing 1-100 g V₂Adding 20-2000 mL of 15-30 mol/L hydrofluoric acid etching solution into AlC for etching for 48-72 h, cleaning with deionized water, centrifuging at the rotating speed of 3500-5000 rpm until the pH is = 6-7, pouring out the supernatant to obtain V₂CT_xPrecipitating; the above V is mixed₂CT_xAdding the precipitate into 50-3000 mL of deionized water, oscillating, centrifuging at the rotating speed of 3500-5000 rpm, and collecting supernatant to obtain V₂CT_xAnd (3) solution.

6. The method for preparing the MXene film with low infrared emissivity as claimed in claim 5, wherein the MXene solution is prepared by the following steps:

freeze-drying MXene precipitate at-40 deg.C and <10pa to obtain MXene powder; and stirring the MXene powder, alkyl chain acyl chloride and triethylamine, mixing and stirring with DMF (dimethyl formamide), washing with absolute ethyl alcohol, centrifuging until the pH is = 6-7, and adding deionized water for ultrasonic treatment to obtain an alkyl chain modified MXene solution.

7. The method for preparing the MXene film with low infrared emissivity as claimed in claim 5, wherein the MXene solution is prepared by the following steps:

freeze-drying MXene precipitate at-40 deg.C and <10pa to obtain MXene powder; and mixing the MXene powder with an alkali solution or an acid solution, washing with deionized water, centrifuging until the pH is = 6-8, and adding deionized water for ultrasonic treatment to obtain the alkali-modified or acid-modified MXene solution.

8. The method for preparing the MXene film with low infrared emissivity as claimed in claim 5, wherein the MXene solution is prepared by the following steps:

freeze-drying MXene precipitate at-40 deg.C and <10pa to obtain MXene powder; mixing MXene powder, a silane coupling agent and an ethanol solution, cleaning with ethanol, centrifuging, and removing unreacted silane coupling agent to obtain suspension, namely the MXene solution modified by the silane coupling agent.

9. The MXene film prepared by the preparation method of the MXene film with the low infrared emissivity as claimed in any one of claims 1-4.

10. The application of the infrared low-emissivity MXene film as claimed in claim 9 in the fields of infrared stealth and thermal camouflage.

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