1. A method for preparing an aerogel composite material with light transmittance regulated by electrothermal, which is characterized by comprising the following steps:

(1) providing an ITO conductive film, uniformly mixing PDMS precursor polymer and paraffin to obtain a PDMS precursor polymer/paraffin mixture, vacuumizing and defoaming the PDMS precursor polymer/paraffin mixture, spin-coating the mixture on the surface of the provided ITO conductive film, and thermally curing the mixture to obtain a double-layer film comprising a PDMS-paraffin transparent adjusting thin layer and the ITO conductive film;

(2) performing atomic layer deposition on the double-layer film obtained in the step (1) to obtain a three-layer film sequentially comprising an amorphous barrier layer, a PDMS-paraffin transparent adjusting thin layer and an ITO conductive film;

(3) performing surface plasma treatment on the three-layer film obtained in the step (2) to enable the surface of the amorphous barrier layer included in the three-layer film to be rich in hydroxyl groups, so as to obtain a plasma treatment film sequentially including the amorphous barrier layer with the surface being rich in hydroxyl groups, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film;

(4) providing transparent aerogel, and carrying out surface plasma treatment on the transparent aerogel to enable one side surface of the transparent aerogel to be rich in hydroxyl groups, so as to obtain plasma-treated transparent aerogel with the surface being rich in hydroxyl groups;

(5) and (3) enabling the surface, rich in hydroxyl, of the amorphous blocking layer included in the plasma treatment film obtained in the step (3) to be in contact with the surface, rich in hydroxyl, of the plasma treatment transparent aerogel obtained in the step (4) and carrying out hot pressing treatment on the surface, so as to obtain the aerogel composite material with light transmittance capable of being regulated and controlled through electrothermal heating.

2. The method of claim 1, wherein:

the PDMS prepolymer is a mixture composed of 184 silicon rubber prepolymer and 184 silicon rubber curing agent, and the mass ratio of the 184 silicon rubber prepolymer to the 184 silicon rubber curing agent is (10-20): 1 is preferably 15: 1;

the paraffin is an alkane mixture with a melting point of 50-100 ℃; and/or

In the step (1), the mass ratio of the PDMS prepolymer to the paraffin wax is 1: (0.1-0.7) is preferably 1: 0.5.

3. The method of claim 1, wherein:

in the step (1), the rotation speed of the spin coating is 2500-3500 rpm, preferably 3000rpm, and the time of the spin coating is 5-50 s, preferably 20 s;

in the step (1), the heat curing temperature is 50-120 ℃, preferably 80 ℃, and the heat curing time is 2-16 h, preferably 8 h; and/or

In the step (1), the thickness of the PDMS-paraffin transparent adjusting thin layer is 5-40 μm, and preferably 15 μm.

4. The production method according to any one of claims 1 to 3, wherein in the step (2), the atomic layer deposition of the bilayer thin film obtained in the step (1) comprises the sub-steps of:

(a) placing the double-layer film into an ALD device cavity, enabling a first reaction precursor to enter the ALD device cavity in a pulse mode and be chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer film, and after the surface of the PDMS-paraffin transparent adjusting thin layer is adsorbed and saturated, blowing the redundant first reaction precursor out of the ALD device cavity by using nitrogen;

(b) allowing a second reaction precursor to enter the ALD device cavity in a pulse mode and perform a deposition reaction with the first reaction precursor chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer thin film in the step (a), and after the reaction is completed, blowing the redundant second reaction precursor and a byproduct generated after the deposition reaction out of the ALD device cavity by using nitrogen gas to form an amorphous barrier layer on the double-layer thin film;

(c) and (c) repeating the step (a) and the step (b) for multiple times in sequence until the thickness of the amorphous barrier layer reaches a preset thickness.

5. The method of claim 4, wherein:

the first reaction precursor is one or more of trimethylaluminum, dimethylaluminum chloride, aluminum chloride and dimethylaluminum isopropoxide, and preferably, the first reaction precursor is trimethylaluminum;

the pulse time of the first reaction precursor is 0.08-0.25 s, preferably 0.15 s;

in the step (a), the time for purging with nitrogen is 10-80 s, preferably 30 s;

the second reaction precursor is one or more of ultrapure water, hydrogen peroxide and ozone, and preferably, the second reaction precursor is ultrapure water;

the pulse time of the second reaction precursor is 0.1-0.35 s, preferably 0.25 s;

in the step (b), the time for purging with nitrogen is 30-120 s, preferably 60 s;

the temperature of the first reaction precursor and the second reaction precursor for deposition reaction is 40-100 ℃, and preferably 65 ℃;

in the step (c), the number of times of repeating the step (a) and the step (b) in sequence is 50-500, preferably 200; and/or

The thickness of the amorphous blocking layer obtained in the step (c) is 5-50 nm, and preferably 20 nm.

6. The production method according to any one of claims 1 to 3, characterized in that:

the transparent aerogel is one or more of transparent silica aerogel, transparent alumina aerogel, transparent zirconia aerogel, transparent titanium oxide aerogel, transparent polyimide aerogel, transparent chitosan aerogel, transparent nano cellulose aerogel, transparent melamine-formaldehyde aerogel, and preferably, the transparent aerogel is transparent silica aerogel.

7. The production method according to any one of claims 1 to 3, characterized in that:

the working atmosphere for performing the surface plasma treatment in the step (3) and/or the step (4) is one or more of air, oxygen, nitrogen and ammonia, preferably, the working atmosphere for performing the surface plasma treatment is air; and/or

The power for carrying out surface plasma treatment in the step (3) and/or the step (4) is 20-500W, and preferably 100W; and/or

The time for performing the surface plasma treatment in the step (3) and/or the step (4) is 10 to 300s, preferably 60 s.

8. The production method according to any one of claims 1 to 3, characterized in that:

in the step (5), the hot pressing pressure of the hot pressing treatment is 0.1-1 MPa, preferably 0.3MPa, the hot pressing temperature of the hot pressing treatment is 60-150 ℃, preferably 90 ℃, and/or the hot pressing time of the hot pressing treatment is 1-30 min, preferably 10 min.

9. An aerogel composite material whose light transmittance can be controlled by electrocaloric light obtained by the production method according to any one of claims 1 to 8; preferably, the aerogel composite, whose light transmittance can be controlled by electro-heating, has one or more of the following properties:

the light transmittance of the aerogel composite material capable of controlling the light transmittance through the electrothermal effect is actively controlled by applying voltage, and the minimum voltage required to be applied is 8V;

the light transmittance of the aerogel composite material with light transmittance regulated by electrothermal can be accurately regulated within the range of 15-85% by regulating the value of applied voltage;

the opaque/transparent switching response speed of the aerogel composite material with the light transmittance regulated and controlled by the electrothermal is high and is within 3 s;

the aerogel composite material with the light transmittance regulated and controlled by the electrothermal effect has the advantages of stable optical performance, stable heat insulation performance and long service life.

10. Application of the aerogel composite material with light transmittance capable of being regulated and controlled by electrothermal prepared by the preparation method of any one of claims 1 to 8 in the fields of smart home, green buildings, energy conservation and environmental protection, commercial display, advertising, precision electronics, aerospace and national defense safety.

Background

Aerogel, a material with three-dimensional nanoporous network structure. Transparent aerogels have attracted considerable attention as an important class of functionalized aerogels due to their specific optical transparency properties. According to different components, the transparent aerogel mainly comprises inorganic oxide transparent aerogel including silica, alumina, zirconia, titanium oxide and the like, and organic transparent aerogel including polyimide, chitosan, nanocellulose, melamine-formaldehyde and the like, wherein the preparation process of the silica aerogel is mature, so that the research on the transparent silica aerogel and the preparation method thereof is more sufficient, but other types of transparent aerogels gradually emerge. The transparent aerogel has the remarkable characteristics of high light transmission, light weight, high heat insulation and the like, and has the outstanding advantages of reducing the weight of a building, preserving heat, insulating heat, saving energy, protecting environment and the like compared with the conventional glass when being used as lighting glass for doors, windows, roofs, curtain walls and the like of the building. In view of this, numerous patents have reported the preparation of various transparent aerogels and their aerogel glasses, such as chinese patent applications CN101468798A, CN105271263A, CN108328621A, CN108623175A, CN105179879A, CN109989681A, etc.

However, the light transmittance of the currently prepared transparent aerogel for glass is fixed, and the transparent aerogel for glass cannot be switched between transparent and opaque according to personal requirements and application scenes, and when the light is not required to be collected, the light is shielded by means of curtains or shutters and the like. In future intelligent house field, aerogel door and window, dome, curtain wall glass ensure under the prerequisite of the excellent heat preservation and thermal insulation effect of building, need have splendid daylighting effect under the condition of work daytime, and then need excellent shading effect when having a rest evening, therefore need develop new generation's light nature of adjusting nature intelligence aerogel and glass, satisfy scenes such as high-end building glass, automobile glass, aviation glass, demonstration glass to the demand of transparent adjustable optical function.

Chinese patent application CN109126643A reports a self-light-modulation transparent composite aerogel material, VO sandwiched between two silica aerogel layers₂Photochromic layer of nanoparticles, VO₂The material is a typical thermochromic material, and during phase change, a low-temperature monoclinic rutile structure is changed into a high-temperature tetragonal rutile structure, so that the optical transmission performance in an infrared light region is subjected to on-off reversible conversion. However, the self-dimming transparent composite aerogel material in the patent application has the obvious disadvantages that firstly, the change of the transmittance of light is in an infrared band, and the requirement that the transmittance is changed in a visible light band in actual life cannot be met; secondly, the trends of transparency at low temperature and opacity at high temperature are completely opposite to the actual requirements of light transmission in the daytime (at high temperature) and light shading at night (at low temperature) in daily life; thirdly, the transparent/opaque switching is carried out depending on the change of the environmental temperature, and the method is a passive mode with low response speed and low sensitivity and cannot quickly adjust the light transmission according to the feedback of the user in time; finally, this strategy is not versatile and cannot be used with a wide variety of transparent aerogel material systems other than silica aerogels.

Therefore, a general light transmittance regulation method for transparent aerogel needs to be developed, so that the prepared intelligent aerogel material can actively, rapidly and reversibly regulate the light transmittance of the aerogel material in a visible light band, and has wide applications in the aspects of buildings, information, electronics, energy, national defense and the like.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides an aerogel composite material with light transmittance regulated by electrothermal, and a preparation method and application thereof. According to the method, the amorphous barrier layer/PDMS-paraffin transparent adjusting thin layer/ITO conductive thin film three-layer thin film is sequentially bonded on the surface of the transparent aerogel to prepare the aerogel composite material with the light transmittance capable of being regulated and controlled through electrothermal regulation, and the light transmittance of the aerogel composite material prepared by the method can be actively, quickly, sensitively, safely, efficiently and long-term regulated and controlled through the electrothermal regulation and control; the method is suitable for sequentially bonding three layers of films of an amorphous barrier layer, a PDMS-paraffin transparent adjusting thin layer and an ITO conductive thin film on the surfaces of various transparent aerogels, so that various transparent aerogel composite materials with light transmittance capable of being adjusted and controlled through electric heating can be obtained.

The present invention provides, in a first aspect, a method for preparing an aerogel composite whose light transmittance can be controlled by electro-heating, the method comprising the steps of:

(1) providing an ITO conductive film, uniformly mixing PDMS precursor polymer and paraffin to obtain a PDMS precursor polymer/paraffin mixture, vacuumizing and defoaming the PDMS precursor polymer/paraffin mixture, spin-coating the mixture on the surface of the provided ITO conductive film, and thermally curing the mixture to obtain a double-layer film comprising a PDMS-paraffin transparent adjusting thin layer and the ITO conductive film;

(2) performing atomic layer deposition on the double-layer film obtained in the step (1) to obtain a three-layer film sequentially comprising an amorphous barrier layer, a PDMS-paraffin transparent adjusting thin layer and an ITO conductive film;

(3) performing surface plasma treatment on the three-layer film obtained in the step (2) to enable the surface of the amorphous barrier layer included in the three-layer film to be rich in hydroxyl groups, so as to obtain a plasma treatment film sequentially including the amorphous barrier layer with the surface being rich in hydroxyl groups, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film;

(4) providing transparent aerogel, and carrying out surface plasma treatment on the transparent aerogel to enable one side surface of the transparent aerogel to be rich in hydroxyl groups, so as to obtain plasma-treated transparent aerogel with the surface being rich in hydroxyl groups;

(5) and (3) enabling the surface, rich in hydroxyl, of the amorphous blocking layer included in the plasma treatment film obtained in the step (3) to be in contact with the surface, rich in hydroxyl, of the plasma treatment transparent aerogel obtained in the step (4) and carrying out hot pressing treatment on the surface, so as to obtain the aerogel composite material with light transmittance capable of being regulated and controlled through electrothermal heating.

Preferably, the PDMS precursor polymer is a mixture of a prepolymer of 184 silicon rubber and a curing agent of 184 silicon rubber, and the mass ratio of the prepolymer of 184 silicon rubber to the curing agent of 184 silicon rubber is (10-20): 1 is preferably 15: 1; the paraffin is an alkane mixture with a melting point of 50-100 ℃; and/or in the step (1), the mass ratio of the PDMS precursor polymer to the paraffin wax is 1: (0.1-0.7) is preferably 1: 0.5.

Preferably, in the step (1), the rotation speed of the spin coating is 2500-3500 rpm, preferably 3000rpm, and the time of the spin coating is 5-50 s, preferably 20 s; in the step (1), the heat curing temperature is 50-120 ℃, preferably 80 ℃, and the heat curing time is 2-16 h, preferably 8 h; and/or in the step (1), the thickness of the PDMS-paraffin transparent adjusting thin layer is 5-40 μm, preferably 15 μm.

Preferably, in the step (2), the atomic layer deposition of the bilayer film obtained in the step (1) comprises the following sub-steps:

(a) placing the double-layer film into an ALD device cavity, enabling a first reaction precursor to enter the ALD device cavity in a pulse mode and be chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer film, and after the surface of the PDMS-paraffin transparent adjusting thin layer is adsorbed and saturated, blowing the redundant first reaction precursor out of the ALD device cavity by using nitrogen;

(b) allowing a second reaction precursor to enter the ALD device cavity in a pulse mode and perform a deposition reaction with the first reaction precursor chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer thin film in the step (a), and after the reaction is completed, blowing the redundant second reaction precursor and a byproduct generated after the deposition reaction out of the ALD device cavity by using nitrogen gas to form an amorphous barrier layer on the double-layer thin film;

(c) and (c) repeating the step (a) and the step (b) for multiple times in sequence until the thickness of the amorphous barrier layer reaches a preset thickness.

Preferably, the first reaction precursor is one or more of trimethylaluminum, dimethylaluminum chloride, aluminum chloride and dimethylaluminum isopropoxide, and preferably, the first reaction precursor is trimethylaluminum; the pulse time of the first reaction precursor is 0.08-0.25 s, preferably 0.15 s; in the step (a), the time for purging with nitrogen is 10-80 s, preferably 30 s; the second reaction precursor is one or more of ultrapure water, hydrogen peroxide and ozone, and preferably, the second reaction precursor is ultrapure water; the pulse time of the second reaction precursor is 0.1-0.35 s, preferably 0.25 s; in the step (b), the time for purging with nitrogen is 30-120 s, preferably 60 s; the temperature of the first reaction precursor and the second reaction precursor for deposition reaction is 40-100 ℃, and preferably 65 ℃; in the step (c), the number of times of repeating the step (a) and the step (b) in sequence is 50-500, preferably 200; and/or the thickness of the amorphous barrier layer obtained in the step (c) is 5-50 nm, preferably 20 nm.

Preferably, the transparent aerogel is one or more of transparent silica aerogel, transparent alumina aerogel, transparent zirconia aerogel, transparent titanium oxide aerogel, transparent polyimide aerogel, transparent chitosan aerogel, transparent nanocellulose aerogel and transparent melamine-formaldehyde aerogel, and preferably, the transparent aerogel is transparent silica aerogel.

Preferably, the working atmosphere for performing the surface plasma treatment in step (3) and/or step (4) is one or more of air, oxygen, nitrogen, ammonia, and preferably, the working atmosphere for performing the surface plasma treatment is air; and/or the power for carrying out surface plasma treatment in the step (3) and/or the step (4) is 20-500W, preferably 100W; and/or the time for performing the surface plasma treatment in the step (3) and/or the step (4) is 10 to 300s, preferably 60 s.

Preferably, in the step (5), the hot pressing pressure of the hot pressing treatment is 0.1-1 MPa, preferably 0.3MPa, the hot pressing temperature of the hot pressing treatment is 60-150 ℃, preferably 90 ℃, and/or the hot pressing time of the hot pressing treatment is 1-30 min, preferably 10 min.

The present invention provides in a second aspect an aerogel composite material having a light transmittance controllable by electrothermal, which is obtained by the production method according to the first aspect of the present invention; preferably, the aerogel composite, whose light transmittance can be controlled by electro-heating, has one or more of the following properties: the light transmittance of the aerogel composite material capable of controlling the light transmittance through the electrothermal effect is actively controlled by applying voltage, and the minimum voltage required to be applied is 8V; the light transmittance of the aerogel composite material with light transmittance regulated by electrothermal can be accurately regulated within the range of 15-85% by regulating the value of applied voltage; the opaque/transparent switching response speed of the aerogel composite material with the light transmittance regulated and controlled by the electrothermal is high and is within 3 s; the aerogel composite material with the light transmittance regulated and controlled by the electrothermal effect has the advantages of stable optical performance, stable heat insulation performance and long service life.

In a third aspect, the invention provides an application of the aerogel composite material with light transmittance regulated and controlled by electrothermal prepared by the preparation method in the first aspect of the invention in the fields of smart home, green buildings, energy conservation and environmental protection, commercial display, advertising, precision electronics, aerospace and national defense safety.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) compared with the transparent aerogel with adjustable light transmittance in other prior art, the aerogel composite material prepared by the invention (abbreviated as aerogel composite material) has the light transmittance which can be adjusted and controlled by electrothermal, the electrothermal adjustment and control is an active adjustment and control strategy, the paraffin in the PDMS-paraffin transparent adjusting thin layer is melted to be in a transparent state by applying voltage to the ITO conductive thin film included in the aerogel composite material for heating, when a power supply is cut off, the paraffin in the PDMS-paraffin transparent adjusting thin layer is re-solidified to be in an opaque state, the transparent/opaque switching is completely actively controllable, can be rapidly changed according to user requirements, has huge practical application value, and is far superior to that the transparent aerogel composite material prepared by adopting paraffin to be passively melted-solidified and phase-changed along with the change of environmental temperature for light transmittance The way of sexual regulation.

(2) The method is suitable for bonding three layers of films of a compact amorphous barrier layer/PDMS-paraffin transparent adjusting thin layer/ITO conductive film on the surfaces of different types of transparent aerogels in sequence to obtain various types of aerogel composite materials with light transmittance capable of being adjusted and controlled by electrothermal, such as conventional silicon dioxide transparent aerogels, other inorganic oxide transparent aerogels including alumina, zirconia, titanium oxide and the like, and organic transparent aerogels including polyimide, chitosan, nano-cellulose, melamine-formaldehyde and the like.

(3) The transparent/opaque switching response speed of the aerogel composite material capable of regulating and controlling the light transmittance through the electrothermal effect is high, when 30V voltage is applied, the local temperature of the PDMS-paraffin transparent regulating thin layer can be increased to 80 ℃ from 25 ℃ within 3s, for example, the solid paraffin in the PDMS polymer framework is rapidly melted to be changed into liquid, and the light transmittance of the silica aerogel composite material is rapidly increased to 85% from 15%.

(4) The prepared aerogel composite material capable of regulating and controlling light transmittance through electric heating has the advantages that paraffin in the PDMS-paraffin transparent regulation thin layer can not leak in tens of thousands of switching voltage cycle operations, the stability of the optical performance and the heat insulation performance of the aerogel composite material is ensured, and the service life of the material is greatly prolonged. On the one hand, the paraffin is locked in the PDMS polymer skeleton structure in the PDMS-paraffin transparent adjusting thin layer, so that the diffusion of the paraffin is limited preliminarily; on the other hand, paraffin cannot diffuse and leak out due to the sealing and blocking effects of the uniform, compact and nano-scale thickness-controllable amorphous blocking layer deposited by ALD to a large extent.

Drawings

FIG. 1 is a reaction scheme of the present invention for preparing aerogel composite materials whose light transmittance can be controlled by electro-thermal. In the figure, the transparent adjusting/conducting double-layer film is a PDMS-paraffin transparent adjusting thin layer/ITO conducting thin layer, the blocking/transparent adjusting/conducting three-layer film is an amorphous blocking layer/PDMS-paraffin transparent adjusting thin layer/ITO conducting thin film, and the blocking/transparent adjusting/conducting three-layer film with the surface rich in hydroxyl is an amorphous blocking layer/PDMS-paraffin transparent adjusting thin layer/ITO conducting thin film with the surface rich in hydroxyl.

FIG. 2 is a schematic diagram of a PDMS-paraffin transparent adjustment layer/ITO conductive layer dual-layer film prepared in example 1 of the present invention. In the figure, 1 represents a PDMS-paraffin transparent adjustment layer/ITO conductive layer double-layer film.

FIG. 3 is the element distribution diagram of the uniform dense amorphous alumina barrier layer with the thickness of 20nm obtained by ALD deposition on a PDMS-paraffin transparent adjusting thin layer/ITO conductive thin layer double-layer film in example 1 of the present invention.

Fig. 4 is a contact angle measurement diagram of a three-layered thin film of an amorphous barrier layer/PDMS-paraffin transparent adjustment thin layer/ITO conductive thin film prepared in example 1 of the present invention before surface plasma treatment.

Fig. 5 is a contact angle measurement diagram of a three-layered thin film of an amorphous barrier layer/PDMS-paraffin transparent adjustment thin layer/ITO conductive thin film prepared in example 1 of the present invention after surface plasma treatment.

FIG. 6 is a view showing the appearance of the transparent silica Aerogel obtained in example 1 of the present invention placed on a sheet of paper filled with an Aerogel. In the figure, 2 represents a transparent silica aerogel.

FIG. 7 is a figure showing the appearance that the silica aerogel composite material, whose light transmittance can be controlled by electrothermal, prepared in example 1 of the present invention becomes transparent after voltage is applied. In the figure, 3 represents a silica aerogel composite material whose light transmittance can be controlled by electrothermal.

FIG. 8 is an outline view of a silica aerogel composite material whose light transmittance can be controlled by electrothermal according to example 1 of the present invention, which becomes opaque after voltage is turned off. In the figure, 3 represents a silica aerogel composite material whose light transmittance can be controlled by electrothermal.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The present invention provides, in a first aspect, a method for preparing an aerogel composite whose light transmittance can be controlled by electro-heating, the method comprising the steps of:

(1) providing an ITO conductive film (also referred to as an ITO conductive layer), uniformly mixing a PDMS precursor and paraffin (molten paraffin) to obtain a PDMS precursor/paraffin mixture, vacuumizing and defoaming the PDMS precursor/paraffin mixture, spin-coating the PDMS precursor/paraffin mixture on the surface of the provided ITO conductive film, performing thermosetting on the surface, and obtaining a PDMS-paraffin transparent adjusting thin layer on one side surface (the surface of the ITO layer) of the ITO conductive film, thereby obtaining a double-layer film comprising the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film; in the invention, a double-layer film comprising a PDMS-paraffin transparent adjusting thin layer and an ITO conductive thin film is also marked as a double-layer film of the PDMS-paraffin transparent adjusting thin layer/the ITO conductive thin film; in the present invention, the PDMS prepolymer is a polydimethylsiloxane prepolymer; the ITO conductive film is formed by coating an ITO layer on an ITO substrate such as PMMA, PC, PET, or a glass plate, that is, the ITO conductive film includes an ITO substrate and an ITO layer coated on the ITO substrate; in the invention, the PDMS precursor polymer/paraffin mixture is spin-coated on the surface of the ITO layer to obtain the PDMS-paraffin transparent adjusting thin layer; the ITO layer is an ITO film (also called as an indium tin oxide film), is an n-type semiconductor material, has high conductivity, high visible light transmittance, high mechanical hardness and good chemical stability, and the ITO substrate is made of PMMA, PC, PET or glass sheets; the thickness of the ITO conductive film is not particularly required, for example, the thickness of the ITO layer included in the ITO conductive film can be 30-80 nm, and the thickness of the ITO substrate included in the ITO conductive film can be 80-200 mu m; in the invention, the PDMS precursor/paraffin mixture is vacuumized and defoamed, for example, the PDMS precursor/paraffin mixture is placed in a vacuum drying oven at a temperature not lower than the melting point corresponding to the paraffin for degassing and defoaming for 1-10 min until the mixture becomes a clear and transparent liquid without bubbles.

(2) Performing Atomic Layer Deposition (ALD) on the double-layer thin film obtained in the step (1) to obtain a three-layer thin film which sequentially comprises an amorphous barrier layer (also called a compact amorphous barrier layer), a PDMS-paraffin transparent adjusting thin layer and an ITO conductive thin film; according to the invention, atomic layer deposition modification is carried out on the surface of one side, away from the ITO conductive film, of the PDMS-paraffin transparent adjusting thin layer contained in the double-layer film obtained in the step (1), and a compact amorphous barrier layer covers the surface of the PDMS-paraffin transparent adjusting thin layer, so that a three-layer film sequentially containing the amorphous barrier layer, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained; in the present invention, the three-layer film including the amorphous barrier layer, the PDMS-paraffin transparent adjustment thin layer, and the ITO conductive thin film is also referred to as the three-layer film of the amorphous barrier layer/the PDMS-paraffin transparent adjustment thin layer/the ITO conductive thin film.

(3) Performing surface plasma treatment on the three-layer film obtained in the step (2) to enable the surface of the amorphous barrier layer included by the three-layer film to be rich in hydroxyl groups, and obtaining a plasma treatment film sequentially including the amorphous barrier layer with the surface being rich in hydroxyl groups, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive thin film; in the invention, after the three thin layers are subjected to surface plasma treatment, the surface of the amorphous barrier layer is rich in hydroxyl, namely the surface of the finally obtained plasma treatment film is considered to be rich in hydroxyl; in the invention, the surface of one side of the amorphous barrier layer, which is far away from the PDMS-paraffin transparent adjusting thin layer, is subjected to surface plasma treatment, so that the surface of the amorphous barrier layer is rich in high-reactivity groups such as hydroxyl groups.

(4) Providing transparent aerogel, and carrying out surface plasma treatment on the transparent aerogel to enable one side surface of the transparent aerogel to be rich in hydroxyl groups, so as to obtain plasma-treated transparent aerogel with the surface being rich in hydroxyl groups; in the invention, after surface plasma treatment is carried out on one side surface of the transparent aerogel, the surface of the transparent aerogel is rich in high-reactivity groups such as hydroxyl groups; in the present invention, the transparent aerogel may be, for example, silica transparent aerogel which is conventional in the prior art, and may also be other inorganic oxide transparent aerogel such as alumina, zirconia, titania, etc., and organic transparent aerogel such as polyimide, chitosan, nanocellulose, melamine-formaldehyde, etc.

(5) Enabling the surface, rich in hydroxyl, of the amorphous blocking layer included in the plasma processing film obtained in the step (3) to be in contact with the surface, rich in hydroxyl, of the plasma processing transparent aerogel obtained in the step (4) and carrying out hot-pressing treatment on the surfaces so that the surfaces in contact are subjected to bonding reaction to prepare the aerogel composite material capable of regulating and controlling light transmittance through electric heating; in the present invention, the heat pressing treatment is also referred to as surface heat pressing treatment or surface contact heat pressing treatment.

Compared with the transparent aerogel with adjustable light transmittance in other prior art, the aerogel composite material (abbreviated as aerogel composite material) prepared by the invention has the advantages that the light transmittance can be adjusted and controlled by electric heating, the electric heating adjustment and control is an active adjustment and control strategy, the paraffin in the PDMS-paraffin transparent adjusting thin layer is melted to be in a transparent state by applying voltage to the ITO conductive thin film included in the aerogel composite material for heating, and when a power supply is cut off, the paraffin in the PDMS-paraffin transparent adjusting thin layer is re-solidified to be not solidified to be in the transparent adjusting thin layerThe transparent state is completely actively controllable, can be rapidly changed according to the requirements of users, has huge practical application value, and is far superior to a method for regulating and controlling the light transmission by passively melting-solidifying phase change of paraffin along with the change of environmental temperature. According to the method, the three layers of films of the compact amorphous barrier layer/PDMS-paraffin transparent adjusting thin layer/ITO conductive thin film are sequentially bonded on the surface of the transparent aerogel, so that the light transmittance of the transparent aerogel can be electrically heated and controlled, the light transmittance of the transparent aerogel can be controlled based on the fact that paraffin is subjected to phase change by applying voltage to generate heat, and the method is independent of the type of the adopted transparent aerogel, and therefore the method is suitable for sequentially bonding the three layers of films of the compact amorphous barrier layer/PDMS-paraffin transparent adjusting thin layer/ITO conductive thin film on the surfaces of different types of transparent aerogels, so that various types of aerogel composite materials with light transmittance capable of being controlled by electrical heating can be obtained; the aerogel composite material prepared by the invention, the light transmittance of which can be regulated and controlled by electrothermal, has high transparent/opaque switching response speed and can be prepared according to the resistance (5 multiplied by 10) of an ITO conductive film^-4Ω · cm) determining the voltage; when a voltage of 30V is applied, the local temperature of the PDMS-paraffin transparent adjusting thin layer can be increased to 80 ℃ from 25 ℃ within 3s, for example, the solid paraffin in the PDMS polymer skeleton is rapidly melted to become liquid, and the light transmittance of the silica aerogel composite material is rapidly increased to 85% from 15%; the prepared aerogel composite material capable of regulating and controlling light transmittance through electric heating has the advantages that paraffin in the PDMS-paraffin transparent regulation thin layer can not leak in tens of thousands of switching voltage cycle operations, the stability of the optical performance and the heat insulation performance of the aerogel composite material is ensured, and the service life of the material is greatly prolonged. On the one hand, the paraffin is locked in the PDMS polymer skeleton structure in the PDMS-paraffin transparent adjusting thin layer, so that the diffusion of the paraffin is limited preliminarily; on the other hand, paraffin cannot diffuse and leak out due to the sealing and blocking effects of the uniform, compact and nano-scale thickness-controllable amorphous blocking layer deposited by ALD to a large extent.

According to some preferred embodiments, the PDMS prepolymer (also referred to as 184 silicone rubber mixture) is a mixture of 184 silicone rubber prepolymer and 184 silicone rubber curing agent, and the mass ratio of the 184 silicone rubber prepolymer to the 184 silicone rubber curing agent is (10-20): 1 (e.g., 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1) is preferably 15: 1; in the invention, the mass ratio of the 184 silicone rubber prepolymer to the 184 silicone rubber curing agent is preferably (10-20): 1, if the mass ratio of the 184 silicon rubber prepolymer to the 184 silicon rubber curing agent is too high, the polymerization speed of the formed PDMS prepolymer is slow and insufficient, and if the mass ratio of the 184 silicon rubber prepolymer to the 184 silicon rubber curing agent is too low, the polymerization speed of the PDMS prepolymer is too fast and uneven; both of these conditions can affect the polymerization effect of the PDMS prepolymer, which in turn affects the locking effect on the paraffin; in the invention, the 184 silicone rubber is Dow Corning 184 silicone rubber, and the Dow Corning 184 silicone rubber comprises a component A: prepolymer, and B-component: a curing agent; when the 184 silicone rubber mixture (namely 184 silicone rubber) is formed, mixing the component A and the component B; the paraffin is an alkane mixture with a melting point of 50-100 ℃; in the invention, the paraffin is preferably a commercial and purchasable alkane mixture, the color is white, and the melting point is within the range of 50-100 ℃ and can be selected as required; and/or in the step (1), the mass ratio of the PDMS precursor polymer to the paraffin wax is 1: (0.1 to 0.7) (e.g., 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, or 1:0.7) is preferably 1: 0.5; in the present invention, it is preferable that the mass ratio of the PDMS prepolymer to the paraffin is 1: (0.1-0.7), if the content of the paraffin is too low, the transparent adjusting effect cannot be achieved; the paraffin content is too high, and the formed PDMS polymer network structure can not effectively lock the paraffin, so that the paraffin is very easy to separate out in the melting and resolidifying process, and the leakage risk is large.

According to some preferred embodiments, in the step (1), the spin coating is performed at a rotation speed of 2500-3500 rpm, preferably 3000rpm, and the spin coating time is 5-50 s (e.g. 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50s), preferably 20 s; in the step (1), the temperature of the thermal curing is preferably 50-120 ℃ (for example, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃ or 120 ℃), and the time of the thermal curing is preferably 2-16 h (for example, 2, 4, 6, 8, 10, 12, 14 or 16h) and is preferably 8 h; and/or in the step (1), the thickness of the PDMS-paraffin transparent adjusting thin layer is 5-40 μm (for example, 5, 10, 15, 20, 25, 30, 35 or 40 μm), and is preferably 15 μm; in the invention, if the thickness of the PDMS-paraffin transparent adjusting thin layer is too small, the opacity under the low-temperature state is mainly influenced; if the thickness is too large, the transparency in a high-temperature state is mainly influenced, and the proper thickness is selected to ensure that the opacity in a low-temperature state and the transparency in a high-temperature state are in a balanced and acceptable value; in some preferred embodiments of the present invention, the thickness of the PDMS-paraffin transparent adjustment thin layer is greater than that of the amorphous barrier layer, because the thickness of the PDMS-paraffin transparent adjustment thin layer directly affects the opacity of the thin layer in a low temperature state and the transparency of the thin layer in a high temperature state, the PDMS-paraffin transparent adjustment thin layer is slightly thicker, the opacity of the thin layer in the low temperature state (paraffin is in a condensed state) is higher, and the transparency of the thin layer in the high temperature state (paraffin is in a liquid state) has a relatively small effect.

According to some preferred embodiments, in the step (2), the Atomic Layer Deposition (ALD) of the bilayer thin film obtained in the step (1) comprises the following sub-steps:

(a) placing the double-layer film into an ALD device cavity (also referred to as an ALD device reaction cavity), allowing a first reaction precursor to enter the ALD device cavity in a pulse mode and be chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer film, and after the surface of the PDMS-paraffin transparent adjusting thin layer is adsorbed and saturated, blowing the redundant first reaction precursor out of the ALD device cavity by using nitrogen;

(b) allowing a second reaction precursor to enter the ALD device cavity in a pulse mode and perform a deposition reaction with the first reaction precursor chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer thin film in the step (a), and after the reaction is completed, blowing the redundant second reaction precursor and a byproduct generated after the deposition reaction out of the ALD device cavity by using nitrogen gas to form an amorphous barrier layer on the double-layer thin film;

(c) repeating the step (a) and the step (b) for multiple times in sequence until the thickness of the amorphous barrier layer reaches a preset thickness; in the present invention, the sequential performance of step (a) and step (b) once is recorded as the completion of one ALD cycle.

ALD is a special chemical vapor deposition technology, precursors and reactants enter an ALD device cavity in an alternate pulse mode, and a uniform and compact thin film is deposited through interface reaction based on a layer-by-layer deposition process of self-limiting gas-solid surface reaction. Furthermore, the layer-by-layer deposition may be repeated until the desired thin layer thickness is obtained. ALD is suitable for preparing high-performance inorganic films with uniform and compact thickness, and has the remarkable advantages of good film uniformity, good compactness, good interface quality, high purity, good shape retention, high step coverage rate and the like compared with other film deposition technologies.

According to some preferred embodiments, the first reaction precursor is one or more of trimethylaluminum, dimethylaluminum chloride, aluminum chloride, dimethylaluminum isopropoxide, preferably, the first reaction precursor is trimethylaluminum; the pulse time of the first reaction precursor is 0.08-0.25 s (e.g., 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, or 0.25s), preferably 0.15 s; in the step (a), the time for purging with nitrogen is 10-80 s (for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 or 80s), and preferably 30 s; the second reaction precursor is one or more of ultrapure water, hydrogen peroxide and ozone, and preferably, the second reaction precursor is ultrapure water; in the present invention, the ultrapure water is also referred to as UP water, which means water having a resistivity of 18 M.OMEGA.times.cm (25 ℃ C.); the pulse time of the second reaction precursor is 0.1-0.35 s (e.g., 0.1, 0.15, 0.2, 0.25, 0.3, or 0.35s), preferably 0.25 s; in the step (b), the time for purging with nitrogen is 30-120 s (for example, 30, 40, 50, 60, 70, 80, 90, 100, 110 or 120s), preferably 60 s; the temperature at which the first reaction precursor and the second reaction precursor undergo the deposition reaction is preferably 40 to 100 ℃ (e.g., 40 ℃, 45 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃) and is preferably 65 ℃; in the step (c), the steps (a) and (b) are sequentially repeated for 50 to 500 times, preferably 200 times (for example, 50, 100, 150, 200, 250, 300, 350, 400, 450 or 500 times); and/or the thickness of the amorphous barrier layer obtained in the step (c) is 5-50 nm (for example, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50nm), and preferably 20 nm; in the invention, the amorphous barrier layer plays a role in isolation while not affecting the overall transparency of the material, and in the invention, the thickness of the amorphous barrier layer is preferably 5-50 nm, and the invention finds that if the thickness of the amorphous barrier layer is too thick, the transparency is greatly affected, and if the thickness of the amorphous barrier layer is too thin, the isolation effect cannot be achieved; in the invention, the amorphous barrier layer is preferably a dense amorphous alumina barrier layer, and the dense amorphous alumina barrier layer can effectively prevent paraffin in the PDMS-paraffin transparent adjusting thin layer from permeating into the aerogel when being heated and melted, and can effectively avoid damage of paraffin to the aerogel structure, the transparency and the heat insulation performance.

According to some preferred embodiments, the transparent aerogel is one or more of transparent silica aerogel, transparent alumina aerogel, transparent zirconia aerogel, transparent titania aerogel, transparent polyimide aerogel, transparent chitosan aerogel, transparent nanocellulose aerogel, transparent melamine-formaldehyde aerogel, preferably, the transparent aerogel is transparent silica aerogel; the transparent aerogel in the invention can be prepared by adopting the transparent aerogel prepared by the prior art.

According to some preferred embodiments, the working atmosphere for performing the surface plasma treatment in step (3) and/or step (4) is one or more of air, oxygen, nitrogen, and ammonia, and preferably, the working atmosphere for performing the surface plasma treatment is air; and/or the power for performing the surface plasma treatment in the step (3) and/or the step (4) is 20-500W (for example, 20, 50, 100, 150, 200, 250, 300, 350, 400, 450 or 500W), and preferably 100W; and/or the surface plasma treatment is carried out in the step (3) and/or the step (4) for 10 to 300s (for example, 10, 30, 60, 100, 150, 200, 250 or 300s), preferably 60 s.

According to some preferred embodiments, in step (5), the hot-pressing pressure of the hot-pressing treatment is 0.1 to 1MPa (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1MPa), preferably 0.3MPa, the hot-pressing temperature of the hot-pressing treatment is 60 to 150 ℃ (e.g., 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, or 150 ℃) preferably 90 ℃, and/or the hot-pressing time of the hot-pressing treatment is 1 to 30min (e.g., 1, 3, 5, 8, 10, 15, 20, 25, or 30min), preferably 10 min; the invention discovers that if the hot pressing pressure is too large, the aerogel with relatively weak strength is easy to damage, and if the hot pressing pressure is too small, the effect of interface hot pressing reaction cannot be achieved; if the hot pressing temperature is too high, some aerogels with poor temperature resistance can shrink or oxidize, so that the structure is damaged; if the hot pressing temperature is too low, the effect of interface hot pressing reaction cannot be achieved; if the hot pressing time is too long, the operation efficiency is affected, the aerogel has a risk of structural damage under long-time hot pressing operation, and if the hot pressing time is too short, the interface hot pressing reaction effect cannot be achieved, so that in the invention, the hot pressing pressure of the hot pressing treatment is preferably 0.1-1 MPa, the hot pressing temperature of the hot pressing treatment is 60-150 ℃, and the hot pressing time of the hot pressing treatment is 1-30 min.

The present invention provides, in a second aspect, an aerogel composite material whose light transmittance can be controlled by electrocaloric effect, obtained by the production method according to the first aspect of the present invention.

According to some preferred embodiments, the aerogel composite whose light transmission can be controlled by electro-heating has one or more of the following properties: the light transmittance control of the aerogel composite material capable of controlling light transmittance through electric heating is actively controllable through voltage application, does not depend on environmental temperature change, requires the minimum applied voltage of 8V, and is very safe; the light transmittance of the aerogel composite material with light transmittance regulated by electrothermal can be accurately regulated within the range of 15-85% as required by regulating the value of applied voltage; the opaque/transparent switching response speed of the aerogel composite material with the light transmittance regulated and controlled by the electrothermal is high and is within 3 s; the aerogel composite material with the light transmittance regulated by the electrothermal effect has stable optical performance, stable heat insulation performance and long service life, and the light transmittance under light transmittance basically keep stable after the transparent/opaque switch is cycled for 10000 times. In the invention, the transparent/opaque switching cycle refers to heating by applying voltage to the ITO conductive film, so that paraffin in the PDMS-paraffin transparent adjusting thin layer is melted to be in a transparent state, when the power supply is switched off, the paraffin in the PDMS-paraffin transparent adjusting thin layer is solidified again to be in an opaque state, and the transparent/opaque switching cycle is recorded as one transparent/opaque switching cycle.

In particular, the light transmittance of the present invention refers to the light transmittance of a sample at 550nm with a thickness of 10mm, and the light transmittance at 550nm is used as an index, because the human eye is most sensitive to visible light with a wavelength of 550 nm. In the invention, the light transmittance is represented by light transmittance, and the light transmittance is represented by transparency on the appearance of the aerogel composite material.

In a third aspect, the invention provides an application of the aerogel composite material with light transmittance regulated and controlled by electrothermal prepared by the preparation method in the first aspect of the invention in the fields of smart home, green buildings, energy conservation and environmental protection, commercial display, advertising, precision electronics, aerospace and national defense safety.

The invention will be further illustrated by way of example, but the scope of protection is not limited to these examples.

Example 1

Firstly, 15g of prepolymer (matrix) of Dow Corning 184 silicone rubber and 1g of curing agent of Dow Corning 184 silicone rubber are put into a beaker, 8g of melted paraffin liquid (melting point 70 ℃) is added into the beaker, and the mixture is fully and uniformly stirred by a glass rod to obtain PDMS precursor polymerParaffin wax mixture. The PDMS precursor/paraffin mixture was placed in a vacuum oven at 70 ℃ for degassing and defoaming for 2min until the mixture became a clear and transparent liquid without bubbles. Placing the super-transparent ITO conductive film on a sucker of a spin coater, pouring a proper amount of clear transparent PDMS precursor/paraffin mixture to the ITO conductive film (resistance 5X 10)^-4Omega cm) away from the spin coater side (the surface of the ITO layer), spin coating and spin coating are carried out at the spin coating speed of 3000rpm and the spin coating time of 20s, namely, a PDMS precursor polymer/paraffin mixture with uniform thickness is paved on the surface of the ITO conductive film, then the ITO conductive film is placed in a drying oven at 80 ℃ to be baked for 8h for complete heat curing, and a PDMS-paraffin transparent adjusting thin layer with the thickness of 15 mu m is coated on the surface of the ITO conductive film, so that the double-layer film comprising the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained.

Placing the PDMS-paraffin transparent adjusting thin layer/the double-layer thin film of the ITO conducting layer into an ALD device cavity, enabling trimethylaluminum (a first reaction precursor) to enter the ALD device cavity in a 0.15s pulse mode by using nitrogen as carrier gas and be chemically adsorbed on the surface of the PDMS-paraffin transparent adjusting thin layer included in the double-layer thin film, and after the surface adsorption of the PDMS-paraffin transparent adjusting thin layer is saturated, purging the redundant trimethylaluminum out of the ALD device cavity by using nitrogen for 30 s. And then ultrapure water enters the ALD device cavity in a 0.25s pulse mode, and is subjected to deposition reaction with trimethylaluminum chemically adsorbed on the surface of the double-layer film at 65 ℃, after the reaction is completed, the redundant ultrapure water (second reaction precursor) and deposition reaction byproducts are blown out of the ALD device cavity by nitrogen, and the blowing time is 60s, so that one ALD cycle is completed. And circulating the ALD for 200 times to obtain a uniform compact amorphous alumina barrier layer with the thickness of 20nm on the double-layer film of the PDMS-paraffin transparent adjusting thin layer/the ITO conductive layer, thereby obtaining a three-layer film sequentially comprising the compact amorphous alumina barrier layer, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film.

Thirdly, placing the three layers of films of the compact amorphous alumina barrier layer/the PDMS-paraffin transparent adjusting thin layer/the ITO conducting layer and the transparent silica aerogel into a cavity of a surface plasma device with the power of 100W, and performing plasma treatment for 60s at room temperature in the air atmosphere, namely respectively enabling the surfaces of the compact amorphous alumina barrier layers and the transparent silica aerogel to be rich in hydroxyl groups, and respectively obtaining the plasma treatment film sequentially comprising the compact amorphous alumina barrier layer with the surface being rich in hydroxyl groups, the PDMS-paraffin transparent adjusting thin layer/the ITO conducting thin layer and the transparent silica aerogel with the surface being rich in hydroxyl groups; the preparation method of the transparent silicon dioxide aerogel comprises the following steps: and (2) performing magnetic stirring on 60g of methanol, 2g of water and 6g of methyl orthosilicate at room temperature, then dropwise adding 3mL of 0.5M ammonia water solution, continuously stirring for 5min to perform sol-gel reaction to obtain wet gel, and performing aging, solvent replacement and supercritical drying to obtain the transparent silicon dioxide aerogel.

Aligning the surface rich in hydroxyl of the plasma treatment film with the surface rich in hydroxyl of the plasma treatment transparent silica aerogel, applying 0.3MPa of hot pressing pressure, and reacting at 90 ℃ for 10min to bond the surfaces of the plasma treatment film and the plasma treatment transparent silica aerogel, thereby preparing the silica aerogel composite material with light transmittance regulated by electrothermal heating.

The density, the room-temperature thermal conductivity and the light transmittance of the aerogel composite material with the light transmittance controlled by electrothermal measurement obtained in the present example are shown in table 1; and the light transmittance change of the aerogel composite material with the light transmittance capable of being regulated and controlled by electrothermal is shown in table 2 after 10000 times of transparent/opaque switch cycle tests.

Example 2

Example 2 is essentially the same as example 1, except that:

the method comprises the following steps: 15g of prepolymer (matrix) of Dow Corning 184 silicone rubber and 1g of curing agent of Dow Corning 184 silicone rubber are put into a beaker, 1.6g of melted paraffin liquid (melting point 50 ℃) (mass ratio of PDMS prepolymer to paraffin is 1:0.1) is added into the beaker, and the mixture is fully and uniformly stirred by a glass rod to obtain PDMS prepolymerA mixture of substance/paraffin. The PDMS precursor/paraffin mixture was placed in a vacuum oven at 50 ℃ for degassing and defoaming for 2min until the mixture became a clear and transparent liquid without bubbles. An ultra-transparent ITO conductive film (resistance 5 multiplied by 10)^-4Omega cm) is placed on a sucker of a spin coater, a proper amount of clear transparent PDMS precursor/paraffin mixture is poured on the surface (the surface of an ITO layer) of the ITO conductive film far away from the spin coater, spin coating is carried out at the spin coating speed of 3000rpm for 20s, glue homogenizing and spin coating are carried out, namely the PDMS precursor/paraffin mixture with uniform thickness is paved on the surface of the ITO conductive film, then the ITO conductive film is placed in a drying oven at 80 ℃ for baking for 8h to be completely thermally cured, and a PDMS-paraffin transparent adjusting thin layer with the thickness of 5 mu m is coated on the surface of the ITO conductive film, so that the double-layer film comprising the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained.

In the second step, the ALD is circulated for 50 times, so that a uniform compact amorphous alumina barrier layer with the thickness of 5nm can be obtained on the double-layer film of the PDMS-paraffin transparent adjusting thin layer/the ITO conductive layer, and a three-layer film sequentially comprising the compact amorphous alumina barrier layer, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained; the other contents of the step (ii) are the same as those of the step (ii) of the embodiment 1.

Aligning the surface rich in hydroxyl of the plasma treatment film with the surface rich in hydroxyl of the plasma treatment transparent silica aerogel, applying 0.1MPa of hot pressing pressure, and reacting at 60 ℃ for 30min to bond the surfaces of the plasma treatment film and the plasma treatment transparent silica aerogel, thereby preparing the silica aerogel composite material with light transmittance regulated by electrothermal effect; the other contents of the step (c) are the same as those of the step (c) of the embodiment 1.

Example 3

Example 3 is essentially the same as example 1, except that:

the method comprises the following steps: 15g of Dow Corning 184 silicone rubber prepolymer (base) and 1g of Dow Corning 184 silicone rubber curing agent were placed in a beaker, to which was added 11.2g of a molten paraffin liquid (melting point 100 ℃ C.)) (the mass ratio of the PDMS precursor to the paraffin was 1:0.7), and the mixture was stirred well with a glass rod to obtain a PDMS precursor/paraffin mixture. The PDMS precursor/paraffin mixture was placed in a vacuum oven at 100 ℃ for degassing and defoaming for 2min until the mixture became a clear and transparent liquid without bubbles. An ultra-transparent ITO conductive film (resistance 5 multiplied by 10)^-4Omega cm) is placed on a sucker of a spin coater, a proper amount of clear transparent PDMS precursor/paraffin mixture is poured on the surface (the surface of an ITO layer) of the ITO conductive film far away from the spin coater, spin coating is carried out at the spin coating speed of 3000rpm for 20s, glue homogenizing and spin coating are carried out, namely the PDMS precursor/paraffin mixture with uniform thickness is paved on the surface of the ITO conductive film, then the ITO conductive film is placed in a drying oven at 80 ℃ for baking for 8h to be completely thermally cured, and a PDMS-paraffin transparent adjusting thin layer with the thickness of 40 mu m is coated on the surface of the ITO conductive film, so that the double-layer film comprising the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained.

In the second step, the ALD is circulated for 500 times, so that a uniform compact amorphous alumina barrier layer with the thickness of 50nm can be obtained on the double-layer film of the PDMS-paraffin transparent adjusting thin layer/the ITO conductive layer, and a three-layer film sequentially comprising the compact amorphous alumina barrier layer, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained; the other contents of the step (ii) are the same as those of the step (ii) of the embodiment 1.

Aligning the surface rich in hydroxyl of the plasma treatment film with the surface rich in hydroxyl of the plasma treatment transparent silica aerogel, applying 1MPa of hot pressing pressure, and reacting at 150 ℃ for 1min to bond the surfaces of the plasma treatment film and the plasma treatment transparent silica aerogel, so as to prepare the silica aerogel composite material capable of regulating light transmittance through electrothermal control; the other contents of the step (c) are the same as those of the step (c) of the embodiment 1.

Example 4

Example 4 is essentially the same as example 1, except that:

in the step I, 13.7g of prepolymer (matrix) of Dow Corning 184 silicon rubber and 2.3g of curing agent of Dow Corning 184 silicon rubber are put into a beaker (the mass ratio of the prepolymer to the curing agent is 6:1), 8g of melted paraffin liquid (melting point is 70 ℃) is added into the beaker, and a glass rod is used for fully and uniformly stirring the mixture to obtain a PDMS prepolymer/paraffin mixture; the other contents of step (r) are the same as those of step (r) in example 1.

Example 5

Example 5 is essentially the same as example 1, except that:

in the step I, 15.38g of prepolymer (matrix) of Dow Corning 184 silicon rubber and 0.62g of curing agent of Dow Corning 184 silicon rubber are put into a beaker (the mass ratio of the prepolymer to the curing agent is 25:1), 8g of melted paraffin liquid (the melting point is 70 ℃) is added into the beaker, and a glass rod is used for fully and uniformly stirring the mixture to obtain a PDMS prepolymer/paraffin mixture; the other contents of step (r) are the same as those of step (r) in example 1.

Example 6

Example 6 is essentially the same as example 1, except that:

in the step I, 15g of prepolymer (matrix) of Dow Corning 184 silicon rubber and 1g of curing agent of Dow Corning 184 silicon rubber are put into a beaker, 14.4g of melted paraffin liquid (melting point 70 ℃) is added into the beaker, and the mass ratio of PDMS precursor to paraffin is 1:0.9, and a glass rod is used for fully and uniformly stirring the mixture to obtain a PDMS precursor/paraffin mixture; the other contents of step (r) are the same as those of step (r) in example 1.

Example 7

Example 7 is essentially the same as example 1, except that:

in the step I, 15g of prepolymer (matrix) of Dow Corning 184 silicon rubber and 1g of curing agent of Dow Corning 184 silicon rubber are put into a beaker, 0.8g of melted paraffin liquid (melting point 70 ℃) is added into the beaker, and the mass ratio of PDMS precursor to paraffin is 1:0.05, and a glass rod is used for fully and uniformly stirring the mixture to obtain a PDMS precursor/paraffin mixture; the other contents of step (r) are the same as those of step (r) in example 1.

Example 8

Example 8 is essentially the same as example 1, except that:

in the first step, a PDMS-paraffin transparent adjusting thin layer with the thickness of 3 microns is coated on the surface of the ITO conductive thin film, so that a double-layer thin film comprising the PDMS-paraffin transparent adjusting thin layer and the ITO conductive thin film is obtained; the other contents of step (r) are the same as those of step (r) in example 1.

In the second step, ALD is circulated for 30 times, a uniform compact amorphous alumina barrier layer with the thickness of 3nm can be obtained on the double-layer film of the PDMS-paraffin transparent adjusting thin layer/the ITO conductive layer, and thus a three-layer film sequentially comprising the compact amorphous alumina barrier layer, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained; the other contents of the step (ii) are the same as those of the step (ii) of the embodiment 1.

Example 9

Example 9 is essentially the same as example 1, except that:

in the first step, a PDMS-paraffin transparent adjusting thin layer with the thickness of 45 microns is coated on the surface of the ITO conductive thin film, so that a double-layer thin film comprising the PDMS-paraffin transparent adjusting thin layer and the ITO conductive thin film is obtained; the other contents of step (r) are the same as those of step (r) in example 1.

In the second step, ALD is circulated for 600 times in a circulating manner, a uniform compact amorphous alumina barrier layer with the thickness of 60nm can be obtained on the double-layer film of the PDMS-paraffin transparent adjusting thin layer/ITO conductive layer, and thus a three-layer film sequentially comprising the compact amorphous alumina barrier layer, the PDMS-paraffin transparent adjusting thin layer and the ITO conductive film is obtained; the other contents of the step (ii) are the same as those of the step (ii) of the embodiment 1.

Example 10

Example 10 is essentially the same as example 1, except that:

the fourth step is: aligning the surface rich in hydroxyl of the plasma treatment film with the surface rich in hydroxyl of the plasma treatment transparent silica aerogel, applying 2MPa of hot pressing pressure, and reacting at 90 ℃ for 10min to bond the surfaces of the plasma treatment film and the plasma treatment transparent silica aerogel, thereby preparing the silica aerogel composite material with light transmittance regulated by electrothermal.

Comparative example 1

The preparation method of the transparent silica aerogel comprises the following steps: and (2) performing magnetic stirring on 60g of methanol, 2g of water and 6g of methyl orthosilicate at room temperature, then dropwise adding 3mL of 0.5M ammonia water solution, continuously stirring for 5min to perform sol-gel reaction to obtain wet gel, and performing aging, solvent replacement and supercritical drying to obtain the transparent silicon dioxide aerogel.

The invention has not been described in detail and is in part known to those of skill in the art.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.