CN113200683A - Preparation method of gasochromic film - Google Patents

Abstract

The invention relates to a preparation method of a gasochromic film, which comprises the following steps: (1) separate preparation of WO₃Sol and prehydrolyzed SiO₂Sol; (2) preparation of WO₃/SiO₂Sol; (3) preparation of WO₃/SiO₂A film. Compared with the prior art, the color-changing film prepared by the invention is doped with acidic SiO₂Homogeneous composite structure after sol-dissolving, doped with alkaline SiO₂The higher porosity after sol-gel greatly improves the cyclicity and temperature resistance of gasochromic.

Description

Preparation method of gasochromic film

Technical Field

The invention relates to the technical field of gasochromic films, in particular to a preparation method of a gasochromic film.

Background

With the increasing prominence of energy problems, the development of renewable energy is still insufficient, so that energy conservation becomes an important means for dealing with the energy problems. The building is one of high energy consumption units, and the building heating and heat preservation energy consumption plays an important role in building energy consumption. According to statistics, under the condition of heating or air conditioning, the heat lost by a single glass window accounts for about 30-50% of the heat load in winter, and the cold consumed by solar radiation heat penetrating through the glass window and entering the room accounts for about 20-30% of the air conditioning load in summer. Therefore, along with the adjustment of national industrial structures and the improvement of the technology, the energy-saving requirement on building energy-saving technology, especially on windows, is higher and higher, and the intelligent color-changing window technology is produced. The gasochromic window is an ideal solar radiation regulation window body, can reduce heat entering the room in summer and enable the heat to smoothly enter the room in winter according to the change of different seasons, and actively regulates the total amount of solar radiation entering the room, thereby realizing the effect of saving energy all the year round. WO based at present on sol-gel technology₃The base gasochromic window has simple process and low cost, is convenient for large-area production and is most close to market application.

WO prepared by sol-gel method₃The film has better gasochromic characteristic, but the discovery of the cycle life shows that the discoloring speed of the film decays very fast along with the increase of discoloring times, and the cycle stability is poorer. On the other hand, the gasochromic window is used as an absorption type energy-saving window, the energy saving in summer is achieved by absorbing solar radiation, and therefore, the temperature of the photochromic film is obviously increased; meanwhile, the sol-gel film needs to be subjected to certain heat treatment to be stable, which requires that the film has certain temperature resistance. But of sol-gel WO₃The temperature resistance of the film is not good, and the color changing speed is greatly changed after heat treatmentSlow. Studies have shown that these two deficiencies are mainly due to the collapse of pores during cycling and heating of the membrane, which hinders the diffusion of hydrogen. Modification of the film is a viable means of property improvement. By using silicon source as precursor to obtain SiO₂Composite improvement WO₃Various gasochromic characteristics are widely researched, SiO₂After compounding, can combine WO₃The clusters are separated, so that WO in the circulating process is effectively prevented₃And (4) structural transformation. In addition to this, SiO₂The skeleton also provides a loose porous skeleton, allowing hydrogen to diffuse more easily within the membrane, thus effectively increasing its cycle life. However, conventional SiO₂The composite film obtained by the composite method cannot have the high transparency and high temperature resistance required by the film, and the structural characteristics of the film need to be further improved so as to improve the gasochromic performance.

Disclosure of Invention

The invention aims to provide a preparation method of a gasochromic film, and the obtained photochromic film has good temperature resistance and good cyclicity.

The purpose of the invention can be realized by the following technical scheme: a preparation method of a gasochromic film comprises the following steps:

(1) separate preparation of WO₃Sol and prehydrolyzed SiO₂Sol;

(2) preparation of WO₃/SiO₂Sol;

(3) preparation of WO₃/SiO₂A film.

The invention makes SiO₂In a state of higher degree of hydrolysis in advance, and then in WO₃Condensation polymerization in the acidic environment of the sol will probably change the SiO₂To obtain SiO under both acidic and alkaline conditions₂The skeleton has the advantages of composite skeleton.

Further, the prehydrolyzed SiO of step (1)₂The sol is obtained by hydrolyzing a silicon source in an ethanol solvent. The prehydrolyzed SiO of the present invention₂The sol is obtained by hydrolyzing in ethanol solvent with silicon source reagent, without using catalyst and other additives, and hydrolyzingThe process is neutral, thereby overcoming the defect of SiO in an acidic environment₂Low degree of hydrolysis resulting in a dense structure after drying and SiO in alkaline environment₂The hydrolysis is not easy to control, which causes the film to be opaque. Is favorable for further processing with WO₃When the sol is compounded, uniform WO grows₃/SiO₂And (3) a framework.

Further, the prehydrolyzed SiO of step (1)₂The preparation method of the sol comprises the following steps: dividing absolute ethyl alcohol into two parts, respectively adding a silicon source and water into the two parts of absolute ethyl alcohol, stirring uniformly, dropwise adding a water-containing ethanol solution into the silicon-containing ethanol solution, mixing and stirring uniformly, standing in a stable environment for aging to obtain prehydrolyzed SiO₂And (3) sol.

Preferably, the molar ratio of the silicon source to the water is 1: 2-1: 6, and the molar ratio of the silicon source to the absolute ethyl alcohol is 1: 10-60. The silicon source used can obtain high hydrolysis degree and good film-forming property through the selection of the proportion, and is convenient for further compounding.

Preferably, the temperature in the standing and aging process is 5-20 ℃, the relative humidity is 30-80%, and the time is 3-7 days. The hydrolysis degree of the silicon source reagent is further improved in the standing aging process, and the silicon source reagent is stabilized into uniform SiO₂And (3) sol.

Preferably, the silicon source comprises one or more of tetraethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, triethoxyethylsilane, and dimethyldiethoxysilane.

WO described in step (1)₃The preparation method of the sol comprises the following steps:

stirring tungsten powder or tungstic acid and 30% hydrogen peroxide solution for reaction for 30-120 min, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1: 3-1: 5, centrifugally separating, filtering to obtain a light yellow transparent solution, adding absolute ethyl alcohol into the obtained solution, carrying out oil bath reflux for 0.5-2 hours at the temperature of 75-85 ℃ until sol is converted into orange color, and obtaining WO₃Ethanol sol;

or: preparing tungsten trioxide sol by sodium tungstate acidification method, and using cation resin exchange methodOr acidifying sodium tungstate aqueous solution into tungstic acid solution by directly adding hydrochloric acid, and adding hydrogen peroxide, ethanol, acetylacetone and other solvents into the solution to obtain WO₃And (3) sol.

WO described in step (1)₃WO in Sol₃The concentration of (a) is 0.2-1.2 mol/L, the prehydrolyzed SiO₂SiO in sol₂The concentration is 0.2 to 1.2 mol/L. The concentration is selected, so that the final composite film has good energy-saving property and good film-forming property.

WO described in step (2)₃/SiO₂The preparation method of the sol comprises the following steps: to prehydrolyzed SiO₂Adding WO into the sol₃Sol is mixed and stirred evenly to obtain WO₃/SiO₂Sol, and WO₃/SiO₂WO in Sol₃With SiO₂The molar ratio of (a) to (b) is 0.5:1 to 3: 1. WO₃Sol addition to prehydrolyzed SiO₂After sol, SiO₂The particles are described in WO₃Condensation polymerization in an acidic environment of the sol to form a network structure, and WO₃The particle dispersibility is good

WO described in step (3)₃/SiO₂The preparation method of the film comprises the following steps:

preparing WO on the surface of clean glass or silicon wafer by using a lifting-pulling immersion plating method₃/SiO₂The film is pulled at a speed of 5-20 cm/min;

or: preparing WO on the surface of clean glass or silicon chip by adopting a spin coating method₃/SiO₂The film has a pre-coating rate of 500-1000 r/min and a spin-coating rate of 2000-3000 r/min;

or: coating WO on glass surface by coating method using wire bar coater or coating sponge₃/SiO₂A film is coated at a speed of 0.1 to 2 m/s;

or: preparing WO on the surface of glass by adopting a spraying method and spraying equipment₃/SiO₂The spraying speed of the film is 1-50 ml/min;

subjecting the obtained WO₃/SiO₂The film is heat treated in air atmosphere, the baking temperature is 50-250 ℃, and the baking time is30～120min。

Compared with the prior art, the invention has the following advantages:

1. the invention makes SiO₂In a state of higher degree of hydrolysis in advance, and then in WO₃The condensation polymerization in the acidic environment of the sol changes SiO₂To obtain SiO under both acidic and alkaline conditions₂The composite framework has the advantages of the framework;

2. prehydrolyzed SiO in the present invention₂The sol is obtained by hydrolyzing in ethanol solvent with silicon source reagent, no catalyst or other additives are used, the hydrolysis process is neutral, and SiO in acidic environment is avoided₂Low degree of hydrolysis resulting in a dense structure after drying and SiO in alkaline environment₂The hydrolysis is not easy to control, so that the film is not transparent;

3. the invention is realized by combining WO₃/SiO₂WO in Sol₃With SiO₂The proportion is controlled to regulate and control the color change depth and the film forming property of the composite film, and the WO is high₃The composite film with the sol content has higher energy-saving regulation and control capability, and SiO₂The proportion of the film is higher, so that the temperature resistance and the film forming property of the film are improved;

4. prehydrolyzed WO complexed by the invention₃/SiO₂Gasochromic film prepared from composite sol and doped with acidic SiO₂Homogeneous composite structure after sol-dissolving, doped with alkaline SiO₂The porosity after sol greatly improves the cyclicity and temperature resistance of gasochromic, has the same hue-causing performance as gasochromic films prepared by magnetron sputtering and other methods, greatly reduces the cost, and has the same advantages as electrochromic films;

5. the color-changing film prepared by the invention has good temperature resistance and cyclicity, and still has good gas-induced color-changing effect after high-temperature heat treatment for 2 hours, thereby meeting the requirements of practical application on heat insulation effect and long-term cyclic use;

6. the method has the advantages of simple steps, stable structure, cheap materials and the like, makes up for the defects of the gasochromic intelligent window prepared by the sol-gel method, leads the technology of the intelligent window to be more mature, and has good industrial production prospect.

Drawings

FIG. 1 shows WO of example 1₃/SiO₂TEM of the composite sol;

FIG. 2 shows WO of example 1₃/SiO₂Transmission spectra of the film in a Bleached state (Bleached state) and a Colored state (Colored state) and a glass substrate;

FIG. 3 shows WO in example 1₃/SiO₂The gasochromic cycle chart of the composite film at different temperatures;

FIG. 4 shows WO of example 1₃/SiO₂The structure schematic diagram of the composite film;

FIG. 5 shows WO in example 1₃/SiO₂Composite film, WO of comparative example 1₃Acid SiO₂Composite film and WO of comparative example 2₃Basic SiO₂The cycle performance of the composite film after heat treatment for 2 hours at 150 ℃ is compared.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation processes are given, but the scope of the invention is not limited to the following examples.

Example 1

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

prehydrolysis of SiO₂The sol is obtained by hydrolyzing a silicon source reagent in an ethanol solvent without a catalyst, wherein the silicon source adopts tetraethyl orthosilicate, the molar ratio of the silicon source to water is 1:2, and the molar ratio of the silicon source to absolute ethanol is 1: 40. The anhydrous ethanol is divided into two parts, the silicon source and the water are respectively added into the two parts of ethanol, and after the mixture is stirred uniformly, one part of solution containing the water is dripped into the silicon source solution. Mixing, stirring, standing in stable environment (5 deg.C, relative humidity 50%), aging for 7 days to obtain prehydrolysis solutionSiO of (2)₂Sol with the concentration of 0.4 mol/L.

(2)WO₃Preparing sol:

stirring and reacting tungsten powder and a hydrogen peroxide (30%) solution for 50 minutes by adopting a sol-gel method, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1:3, centrifugally separating, and filtering to obtain a light yellow transparent solution; adding absolute ethyl alcohol into the obtained solution to adjust the concentration to the required concentration, and refluxing in an oil bath at 85 ℃ for 2 hours until the sol is turned into orange color to obtain WO₃And (5) ethanol sol.

(3)WO₃/SiO₂Preparing sol:

adding the sol obtained in the step (2) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂The molar ratio is 1: 1. Using transmission electron microscope to WO₃/SiO₂The microstructure test results of the sol are shown in FIG. 1, and WO obtained by this method₃/SiO₂In sol, SiO₂The net structure is uniformly inserted into WO₃In the network structure, SiO is shown₂And WO₃A uniform cross-linked framework is compounded.

(4)WO₃/SiO₂Preparing a film:

WO is prepared on the surface of clean glass or silicon wafer by adopting a pulling immersion plating method₃/SiO₂The film is pulled at a speed of 5 cm/min;

subjecting the obtained WO₃/SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50 ℃ and the baking time is 60 minutes to obtain WO₃/SiO₂And (3) compounding the film.

To the WO₃/SiO₂The performance test of the composite film is carried out, and the results are shown in FIGS. 2-4.

The WO obtained can be seen from FIG. 2₃/SiO₂The composite film has a color-causing infrared band transmittance of 10-20%, and has a good energy-saving effect. And compounded SiO₂Has the effect of increasing the permeability, so that WO₃/SiO₂The film has a transmittance in the bleached state that is similar to that of glass itself.

The WO obtained can be seen from FIG. 3₃/SiO₂The composite film has good heat resistance, and still has certain cycle performance after heat treatment at 150 ℃, thereby meeting the requirements of the film in practical application.

WO can be seen from FIG. 4₃/SiO₂The composite framework structure of the composite film has WO₃+ acidic SiO₂High uniformity of skeleton composition and WO₃+ basic SiO₂The skeleton of (2) has high porosity.

Example 2

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

prehydrolysis of SiO₂The sol is obtained by hydrolyzing a silicon source reagent in an ethanol solvent without a catalyst, wherein the silicon source adopts methyl triethoxysilane, the molar ratio of the silicon source to water is 1:2, and the molar ratio of the silicon source to absolute ethanol is 1: 40. The anhydrous ethanol is divided into two parts, the silicon source and the water are respectively added into the two parts of ethanol, and after the mixture is stirred uniformly, one part of solution containing the water is dripped into the silicon source solution. After being mixed and stirred evenly, the mixture is placed in a stable environment (5 ℃, the relative humidity is 50 percent) and is kept stand and aged for 7 days, and the prehydrolyzed SiO2 sol with the concentration of 0.4mol/L can be obtained.

(2)WO₃Preparing sol:

stirring and reacting tungsten powder and a hydrogen peroxide (30%) solution for 50 minutes by adopting a sol-gel method, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1:3, centrifugally separating, and filtering to obtain a light yellow transparent solution; adding absolute ethyl alcohol into the obtained solution to adjust the concentration to the required concentration, and refluxing in an oil bath at 85 ℃ for 2 hours until the sol is turned into orange color to obtain WO₃And (5) ethanol sol.

(3)WO₃/SiO₂Preparing sol:

adding the sol obtained in the step (2) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂The molar ratio is 1: 1.

(4)WO₃/SiO₂Preparing a film:

by means of a handlePreparation of WO on clean glass or silicon chip surface by drawing and dipping method₃/SiO₂The film is pulled at a speed of 5 cm/min;

subjecting the obtained WO₃/SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50 ℃ and the baking time is 60 minutes to obtain WO₃/SiO₂And (3) compounding the film.

Example 3

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

prehydrolysis of SiO₂The sol is obtained by hydrolyzing a silicon source reagent in an ethanol solvent without a catalyst, wherein the silicon source adopts tetraethyl orthosilicate, the molar ratio of the silicon source to water is 1:2, and the molar ratio of the silicon source to absolute ethanol is 1: 20. The anhydrous ethanol is divided into two parts, the silicon source and the water are respectively added into the two parts of ethanol, and after the mixture is stirred uniformly, one part of solution containing the water is dripped into the silicon source solution. Mixing, stirring, standing in stable environment (5 deg.C, relative humidity 50%), aging for 7 days to obtain prehydrolyzed SiO₂Sol with the concentration of 0.8 mol/L.

(2)WO₃Preparing sol:

preparing tungsten trioxide sol by sodium tungstate acidification method, acidifying sodium tungstate solution with certain concentration into tungstic acid solution by cation resin exchange method or directly adding hydrochloric acid, adding stabilizer such as hydrogen peroxide, ethanol, acetylacetone, etc., or replacing part of water with ethanol after adding hydrogen peroxide, to obtain WO₃And (5) ethanol sol.

(3)WO₃/SiO₂Preparing sol:

adding the sol obtained in the step (2) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂The molar ratio is 1: 1.

(4)WO₃/SiO₂Preparing a film:

WO is prepared on the surface of clean glass or silicon wafer by adopting a pulling immersion plating method₃/SiO₂Film, pulling speed 5cm/min；

Subjecting the obtained WO₃/SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50 ℃ and the baking time is 60 minutes to obtain WO₃/SiO₂And (3) compounding the film.

Example 4

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

prehydrolysis of SiO₂The sol is obtained by hydrolyzing a silicon source reagent in an ethanol solvent without a catalyst, wherein the silicon source adopts tetraethyl orthosilicate, the molar ratio of the silicon source to water is 1:2, and the molar ratio of the silicon source to absolute ethanol is 1: 40. The anhydrous ethanol is divided into two parts, the silicon source and the water are respectively added into the two parts of ethanol, and after the mixture is stirred uniformly, one part of solution containing the water is dripped into the silicon source solution. Mixing, stirring, standing in stable environment (5 deg.C, relative humidity 50%), aging for 3 days to obtain prehydrolyzed SiO₂Sol with the concentration of 0.4 mol/L.

(2)WO₃Preparing sol:

stirring and reacting tungsten powder and a hydrogen peroxide (30%) solution for 50 minutes by adopting a sol-gel method, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1:3, centrifugally separating, and filtering to obtain a light yellow transparent solution; adding absolute ethyl alcohol into the obtained solution to adjust the concentration to the required concentration, and refluxing in an oil bath at 85 ℃ for 2 hours until the sol is turned into orange color to obtain WO₃And (5) ethanol sol.

(3)WO₃/SiO₂Preparing sol:

adding the sol obtained in the step (2) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂The molar ratio was 2: 1. To WO₃/SiO₂Sol gel

(4)WO₃/SiO₂Preparing a film:

coating WO on glass surface by coating method using wire bar coater or coating sponge₃/SiO₂Film coating speed 0.1 m/s.

Subjecting the obtained WO₃/SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50 ℃ and the baking time is 60 minutes to obtain WO₃/SiO₂And (3) compounding the film.

Example 5

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

prehydrolysis of SiO₂The sol is obtained by hydrolyzing a silicon source reagent in an ethanol solvent without a catalyst, wherein the silicon source adopts tetraethyl orthosilicate, the molar ratio of the silicon source to water is 1:4, and the molar ratio of the silicon source to absolute ethanol is 1: 40. The anhydrous ethanol is divided into two parts, the silicon source and the water are respectively added into the two parts of ethanol, and after the mixture is stirred uniformly, one part of solution containing the water is dripped into the silicon source solution. Mixing, stirring, standing in stable environment (5 deg.C, relative humidity 50%), aging for 3 days to obtain prehydrolyzed SiO₂Sol with the concentration of 0.4 mol/L.

(2)WO₃Preparing sol:

stirring and reacting tungsten powder and a hydrogen peroxide (30%) solution for 50 minutes by adopting a sol-gel method, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1:4, centrifugally separating, and filtering to obtain a light yellow transparent solution; adding absolute ethyl alcohol into the obtained solution to adjust the concentration to the required concentration, and refluxing in an oil bath at 85 ℃ for 2 hours until the sol is turned into orange color to obtain WO₃And (5) ethanol sol.

(3)WO₃/SiO₂Preparing sol:

adding the sol obtained in the step (2) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂The molar ratio is 1: 1.

(4)WO₃/SiO₂Preparing a film:

WO is prepared on the surface of clean glass or silicon wafer by adopting a pulling immersion plating method₃/SiO₂The film is pulled at a speed of 5 cm/min;

subjecting the obtained WO₃/SiO₂The film is subjected to heat treatment in the air atmosphere, and the baking temperature isAt 150 ℃ for 120 minutes, to obtain WO₃/SiO₂And (3) compounding the film.

Example 6

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

the silicon source adopts dimethyl diethoxy silane, the molar ratio of the silicon source to water is 1:6, the molar ratio of the silicon source to absolute ethyl alcohol is 1:10, the absolute ethyl alcohol is divided into two parts, the silicon source and the water are respectively added into the two parts of absolute ethyl alcohol, after uniform stirring, the aqueous ethyl alcohol solution is dripped into the ethyl alcohol solution containing the silicon source, after uniform mixing and stirring, the mixture is placed in a stable environment (20 ℃, the relative humidity is 30 percent) and is kept stand and aged for 5 days, and the prehydrolyzed SiO is obtained₂Sol with concentration of 1.2 mol/L.

(2)WO₃Preparing sol:

stirring tungstic acid and 30% hydrogen peroxide solution for reaction for 120min, wherein the molar ratio of tungstic acid to hydrogen peroxide is 1:5, centrifugally separating, filtering to obtain a light yellow transparent solution, adding absolute ethyl alcohol into the obtained solution, refluxing in an oil bath at 75 ℃ for 0.5 h until the sol is converted into orange color, thus obtaining WO₃Ethanol sol with the concentration of 1.2 mol/L.

(3)WO₃/SiO₂Preparing sol:

to prehydrolyzed SiO₂Adding WO into the sol₃Sol is mixed for 2 hours to obtain WO₃/SiO₂Sol, and WO₃/SiO₂WO in Sol₃With SiO₂Is 3: 1.

(4)WO₃/SiO₂Preparing a film:

preparing WO on the surface of clean glass or silicon chip by adopting a spin coating method₃/SiO₂The film has a pre-coating rate of 500-1000 r/min and a spin-coating rate of 2000-3000 r/min.

Subjecting the obtained WO₃/SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 250 ℃ and the baking time is 30 minutes to obtain WO₃/SiO₂Composite film。

Example 7

A preparation method of a gasochromic film specifically comprises the following steps:

(1) prehydrolyzed SiO₂Preparing sol:

the silicon source adopts methyltrimethoxysilane, the molar ratio of the silicon source to water is 1:4, the molar ratio of the silicon source to absolute ethyl alcohol is 1:80, the absolute ethyl alcohol is divided into two parts, the silicon source and the water are respectively added into the two parts of the absolute ethyl alcohol, after uniform stirring, the aqueous ethyl alcohol solution is dripped into the ethyl alcohol solution containing the silicon source, after uniform mixing and stirring, the mixture is placed in a stable environment (10 ℃, the relative humidity is 30 percent) to stand and age for 5 days, and the prehydrolyzed SiO is obtained₂Sol with the concentration of 0.2 mol/L.

(2)WO₃Preparing sol:

stirring tungstic acid and 30% hydrogen peroxide solution for reaction for 30min, wherein the molar ratio of tungstic acid to hydrogen peroxide is 1:5, centrifugally separating, filtering to obtain a light yellow transparent solution, adding absolute ethyl alcohol into the obtained solution, refluxing in an oil bath at 70 ℃ for 1 hour until the sol is converted into orange color, thus obtaining WO₃Ethanol sol with the concentration of 0.2 mol/L.

(3)WO₃/SiO₂Preparing sol:

to prehydrolyzed SiO₂Adding WO into the sol₃Sol is mixed for 2 hours to obtain WO₃/SiO₂Sol, and WO₃/SiO₂WO in Sol₃With SiO₂Is 0.5: 1.

(4)WO₃/SiO₂Preparing a film:

preparing WO on the surface of glass by adopting a spraying method and spraying equipment₃/SiO₂The spraying speed of the film is 1-50 ml/min;

subjecting the obtained WO₃/SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 150 ℃ and the baking time is 60 minutes to obtain WO₃/SiO₂And (3) compounding the film.

Comparative example 1

(1)WO₃Preparing sol:

stirring and reacting tungsten powder and a hydrogen peroxide (30%) solution for 50 minutes by adopting a sol-gel method, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1:3, centrifugally separating, and filtering to obtain a light yellow transparent solution; adding absolute ethyl alcohol into the obtained solution to adjust the concentration to the required concentration, and refluxing in an oil bath at 85 ℃ for 2 hours until the sol is turned into orange color to obtain WO₃Ethanol sol with the concentration of 1.2 mol/L.

(2)WO₃Acid SiO₂Preparing sol:

adding TEOS (tetraethyl orthosilicate) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂Stirring for 2h with the molar ratio of 1: 1.

(3)WO₃Acid SiO₂Preparing a film:

WO is prepared on the surface of clean glass or silicon wafer by adopting a pulling immersion plating method₃Acid SiO₂The film is pulled at a speed of 5 cm/min;

subjecting the obtained WO₃Acid SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50 ℃ and the baking time is 60 minutes to obtain WO₃Acid SiO₂And (3) compounding the film.

Comparative example 2

(2)WO₃Preparing sol:

stirring and reacting tungsten powder and a hydrogen peroxide (30%) solution for 50 minutes by adopting a sol-gel method, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1:3, centrifugally separating, and filtering to obtain a light yellow transparent solution; adding absolute ethyl alcohol into the obtained solution to adjust the concentration to the required concentration, and refluxing in an oil bath at 85 ℃ for 2 hours until the sol is turned into orange color to obtain WO₃Ethanol sol with the concentration of 1.2 mol/L.

(1) Basic SiO₂Preparing sol:

the silicon source adopts tetraethyl orthosilicate, wherein the molar ratio of the silicon source to the concentrated ammonia water is 1:2, and the molar ratio of the silicon source to the absolute ethyl alcohol is 1: 30. The anhydrous ethanol is divided into two parts, the silicon source and the concentrated ammonia water are respectively added into the two parts of ethanol, after the mixture is stirred evenly, one part of solution containing the concentrated ammonia water is dripped into the silicon source solution. MixingStirring uniformly, standing and aging in a stable environment (5 deg.C, relative humidity 50%) for 7 days, and refluxing at 80 deg.C until ammonia catalyst in the sol is removed to obtain final alkaline SiO₂Sol with the concentration of 0.4 mol/L.

(2)WO₃Basic SiO₂Preparing sol:

adding TEOS (tetraethyl orthosilicate) into the sol obtained in the step (1) according to a dispersion ratio WO₃：SiO₂Stirring for 2h with the molar ratio of 1: 1.

(3)WO₃Basic SiO₂Preparing a film:

WO is prepared on the surface of clean glass or silicon wafer by adopting a pulling immersion plating method₃Basic SiO₂The film is pulled at a speed of 5 cm/min;

subjecting the obtained WO₃Basic SiO₂Carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50 ℃ and the baking time is 60 minutes to obtain WO₃Basic SiO₂And (3) compounding the film.

WO in example 1₃/SiO₂Composite film, WO of comparative example 1₃Acid SiO₂Composite film and WO of comparative example 2₃Basic SiO₂The comparison of the cycle performance of the composite film after heat treatment at 150 ℃ for 2h is shown in FIG. 5, and it can be seen that WO₃Prehydrolysis of SiO₂Compared with the acid SiO by the composite film₂And basic SiO₂The composite film has better heat resistance.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims (10)

1. The preparation method of the gasochromic film is characterized by comprising the following steps:

(1) separate preparation of WO₃Sol and prehydrolyzed SiO₂Sol;

(2) preparation of WO₃/SiO₂Sol;

(3) preparation of WO₃/SiO₂A film.

2. The method of claim 1, wherein the prehydrolyzed SiO in step (1) is₂The sol is obtained by hydrolyzing a silicon source in an ethanol solvent.

3. The method of claim 2, wherein the prehydrolyzed SiO in step (1) is₂The preparation method of the sol comprises the following steps: dividing absolute ethyl alcohol into two parts, respectively adding a silicon source and water into the two parts of absolute ethyl alcohol, stirring uniformly, dropwise adding a water-containing ethanol solution into the silicon-containing ethanol solution, mixing and stirring uniformly, standing in a stable environment for aging to obtain prehydrolyzed SiO₂And (3) sol.

4. The method for preparing a gasochromic film according to claim 3, wherein the molar ratio of the silicon source to the water is 1: 2-1: 6, and the molar ratio of the silicon source to the absolute ethyl alcohol is 1: 10-60.

5. The method for preparing the gasochromic film according to claim 3, wherein the temperature in the standing and aging process is 5-20 ℃, the relative humidity is 30-80%, and the time is 3-7 days.

6. The method of claim 2, wherein the silicon source comprises one or more of tetraethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, triethoxyethylsilane, and dimethyldiethoxysilane.

7. The method for producing a gasochromic film as defined in claim 1, wherein said WO of step (1)₃The preparation method of the sol comprises the following steps:

stirring tungsten powder or tungstic acid and 30% hydrogen peroxide solution for reaction for 30-120 min, wherein the molar ratio of the tungsten powder to the hydrogen peroxide is 1: 3-1: 5, centrifugally separating, filtering to obtain a light yellow transparent solution, adding absolute ethyl alcohol into the obtained solution, carrying out oil bath reflux for 0.5-2 hours at the temperature of 75-85 ℃ until sol is converted into orange color, and obtaining WO₃Ethanol sol;

or: preparing tungsten trioxide sol by sodium tungstate acidification method, acidifying sodium tungstate aqueous solution into tungstic acid solution by cation resin exchange method or directly adding hydrochloric acid, and adding hydrogen peroxide, ethanol and acetylacetone into the tungstic acid solution to obtain WO₃And (3) sol.

8. The method for producing a gasochromic film as defined in claim 1, wherein said WO of step (1)₃WO in Sol₃The concentration of (a) is 0.2-1.2 mol/L, the prehydrolyzed SiO₂SiO in sol₂The concentration is 0.2 to 1.2 mol/L.

9. The method of producing a gasochromic film as defined in claim 1, wherein said WO of step (2)₃/SiO₂The preparation method of the sol comprises the following steps: to prehydrolyzed SiO₂Adding WO into the sol₃Sol is mixed and stirred evenly to obtain WO₃/SiO₂Sol, and WO₃/SiO₂WO in Sol₃With SiO₂The molar ratio of (a) to (b) is 0.5:1 to 3: 1.

10. The method of producing a gasochromic film as defined in claim 1, wherein said WO of step (3)₃/SiO₂The preparation method of the film comprises the following steps:

preparing WO on the surface of clean glass or silicon wafer by using a lifting-pulling immersion plating method₃/SiO₂Film, pullingThe speed is 5-20 cm/min;

or: preparing WO on the surface of clean glass or silicon chip by adopting a spin coating method₃/SiO₂The film has a pre-coating rate of 500-1000 r/min and a spin-coating rate of 2000-3000 r/min;

or: coating WO on glass surface by coating method using wire bar coater or coating sponge₃/SiO₂A film is coated at a speed of 0.1 to 2 m/s;

or: preparing WO on the surface of glass by adopting a spraying method and spraying equipment₃/SiO₂The spraying speed of the film is 1-50 ml/min;

subjecting the obtained WO₃/SiO₂And carrying out heat treatment on the film in an air atmosphere, wherein the baking temperature is 50-250 ℃, and the baking time is 30-120 min.

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