A preparation method of an ultra-light and ultra-thin nano-electric heating film

Abstract

The present invention provides a method for preparing an ultra-light and ultra-thin nano electrothermal film, comprising the following steps: preparing a micro-nano material dispersion; placing a support film with multiple through-holes on the liquid surface of the micro-nano material dispersion; heating the micro-nano material dispersion while the support film and the micro-nano material dispersion are in a static state, and forming a micro-nano material self-assembly structure on the lower surface of the support film; performing a drying treatment on the micro-nano material self-assembly structure to obtain a micro-nano material self-assembly film; connecting an electrode sheet to each of the two side edges of the micro-nano material self-assembly film to obtain a micro-nano material electrothermal film. The present invention can prepare a micro-nano material electrothermal film with a relatively large area by adjusting the size of the support film, and the thickness of the prepared electrothermal film is controllable and uniform; no surfactant needs to be added during the whole preparation process, and the process is environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-nano material electrothermal films, and particularly relates to a method for preparing an ultra-light and ultra-thin nano electrothermal film. Background Art

[0002] Micro-nano materials refer to materials with particle sizes in the micron and nano scales. A certain micro-nano material can be used, such as preparing a graphene electrothermal film with graphene as the main raw material. In the prior art, for the preparation of a graphene electrothermal film, graphene is first prepared into an aqueous slurry, and then the graphene electrothermal film is prepared by a doctor blade method, and then electrode sheets are installed on the graphene electrothermal film. However, the above prior art has the following problems: 1. The preparation process of the graphene aqueous slurry requires the use of multiple compounds, resulting in certain chemical pollution; 2. The graphene electrothermal film prepared by the doctor blade method has the problem of uneven film thickness, resulting in a slow heating rate or uneven heating temperature distribution during electrothermal heating; 3. During the preparation, the environmental temperature also needs to be changed from 60 - 150 °C during the film drying process, consuming a large amount of energy. For other types of micro-nano materials, such as using MXene to prepare an electrothermal film, the prior art is similar to the preparation method of the graphene electrothermal film, so there are similar problems.

[0003] Therefore, there is an urgent need for an environmentally friendly method that can be used to prepare electrothermal films with large area and uniform thickness for different types of micro-nano materials. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention proposes the following technical solutions:

[0005] In a first aspect, a method for preparing an ultra-light and ultra-thin nano electrothermal film is provided, including the following steps:

[0006] Prepare a micro-nano material dispersion;

[0007] Place a support film with multiple through holes on the surface of the micro-nano material dispersion, where the aperture of the through holes is larger than the diameter of the solvent molecules and smaller than the diameter of the micro-nano material particles;

[0008] While the support film and the micro-nano material dispersion are in a static state, heat the micro-nano material dispersion, and micro-nano material particles form a micro-nano material self-assembled structure on the lower surface of the support film;

[0009] Perform a drying treatment on the micro-nano material self-assembled structure to obtain a micro-nano material self-assembled film;

[0010] Connect an electrode sheet to each of the two side edges of the micro-nano material self-assembled film to obtain a micro-nano material electrothermal film.

[0011] Further, the micro-nano materials include MXene, carbon nanotubes, or graphene oxide.

[0012] Further, the concentration of the micro-nano material dispersion is 0.1 g / L to 5 g / L.

[0013] Further, the support membrane includes an organic membrane or an inorganic membrane; the organic membrane includes a polyethersulfone membrane or a polypropylene membrane, and the inorganic membrane is an aluminum oxide inorganic membrane.

[0014] Further, the pore diameter of the through holes is 20 nanometers to 5 micrometers.

[0015] Further, when heating the micro-nano material dispersion while the support membrane and the micro-nano material dispersion are in a static state, a water bath method is used for heating, the heating temperature is 40 to 85 °C, and the heating time is 30 minutes to 48 hours.

[0016] Further, the drying treatment includes natural air drying or vacuum drying.

[0017] Further, the reduced graphene oxide self-assembled film needs to be subjected to a reduction treatment.

[0018] Further, the reduction treatment of the reduced graphene oxide self-assembled film includes: putting the reduced graphene oxide self-assembled film into a reducing agent solution and heating it in a water bath at 80 °C for 2 hours.

[0019] As can be seen from the above technical solutions, the beneficial technical effects of the present invention are as follows:

[0020] 1. Through the evaporation of water molecules, convection is generated inside the micro-nano material dispersion, driving the micro-nano particles to move directionally towards the support membrane with through holes, and thus a micro-nano material thin film can be self-assembled; according to the different micro-nano materials, further treatments are selectively carried out, such as reducing graphene oxide, to improve the conductivity of the micro-nano material thin film; then the electrode sheet is connected to the micro-nano material self-assembled thin film to obtain a micro-nano material electrothermal thin film. No surfactant needs to be added during the whole preparation process, and the process is environmentally friendly.

[0021] 2. In specific applications, a larger-area micro-nano material electrothermal thin film can be prepared by adjusting the size of the support membrane. The prepared large-area electrothermal thin film can achieve uniform and controllable thickness, and an ultra-light and ultra-thin large-area electrothermal thin film can be prepared.

[0022] In the second aspect, a micro-nano material electrothermal thin film is provided, which is prepared by using the method provided in the first aspect. Description of the Drawings

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0024] Figure 1 Flow chart of the preparation method of the electrothermal film according to an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of the self-assembly principle of micro-nano materials according to an embodiment of the present invention;

[0026] Figure 3 Effect diagram of the graphene electrothermal film prepared according to an embodiment of the present invention;

[0027] Figure 4 Heating conditions of the graphene electrothermal film prepared according to an embodiment of the present invention under different voltages;

[0028] Reference numerals:

[0029] 1 - Support film, 2 - Through hole of the support film, 3 - Micro-nano material dispersion liquid, 4 - Micro-nano material particles. Specific embodiments

[0030] The following will describe in detail the embodiments of the technical solutions of the present invention with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and therefore are only examples and cannot be used to limit the protection scope of the present invention.

[0031] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which the present invention belongs.

[0032] Example 1

[0033] This embodiment provides a preparation method of an ultra-light and ultra-thin nano electrothermal film. As Figure 1 shown, the following steps are carried out:

[0034] The materials required for the electrothermal film preparation method include: micro-nano materials, a support film, and electrode sheets.

[0035] In a specific embodiment, the micro-nano materials include: MXene, carbon nanotubes (CNT), or graphene oxide (GO). Among them, MXene is a two-dimensional inorganic compound composed of several atomic layer thicknesses of transition metal carbides, nitrides, or carbonitrides.

[0036] Supporting film, which is a film with multiple through-holes in a specific embodiment, such as a microfiltration membrane. The material, size, and thickness of the supporting film are not limited; in a specific embodiment, the supporting film is selected according to different micro-nano material suspensions, and an organic film or an inorganic film can be used; the organic film is preferably a polyethersulfone film or a polypropylene film, and the inorganic film is preferably an aluminum oxide (Al2O3) inorganic film. The supporting film can be selected in a roll form (wrapped into a roll) or a sheet form; the pore diameter of the through-holes on the supporting film is larger than the diameter of the solvent molecules and smaller than the diameter of the micro-nano material particles, and the pore diameter of the through-holes is preferably 20 nanometers to 5 micrometers. Since the supporting film may curl or fold during storage, the pretreatment of the supporting film includes flattening and cleaning the supporting film. The form of flattening the supporting film is not limited. In a specific embodiment, for the organic film, mechanical means (such as pressing with a metal plate) can be used for flattening, and for the inorganic film, scraping and grinding can be used for flattening.

[0037] Electrode sheet, used to supply power to the electrothermal film. In a specific embodiment, the electrode sheet is a metal sheet with high conductivity, and its material, size, and thickness are not limited. A copper electrode sheet is preferred.

[0038] 1. Preparation of micro-nano material dispersion

[0039] In a specific embodiment, the solvent of the micro-nano material dispersion is not limited as long as the micro-nano materials can be evenly dispersed, such as water, ethanol, and water is preferably used as the solvent. The micro-nano material dispersion can be prepared by any method in the prior art, and the ultrasonic dispersion method is preferably used to prepare the micro-nano material dispersion. During ultrasonic dispersion, the equipment used is an ultrasonic cleaner, and the time is determined according to the dispersion degree of the required micro-nano material dispersion until it is evenly dispersed. In one embodiment, the ultrasonic dispersion time is 30 minutes. In a specific embodiment, the concentration of the micro-nano material dispersion is adjusted by controlling the solute mass, and its concentration is preferably 0.1 g / L to 5 g / L.

[0040] During ultrasonic dispersion, it is necessary to cool the micro-nano material dispersion to prevent the high temperature caused by ultrasonic waves from damaging the structure of the micro-nano materials. In a specific embodiment, the ice-water bath method is used for cooling for 2 to 3 minutes, and the cooling temperature is slightly lower than room temperature.

[0041] It should be noted that surfactants may be added during the preparation of the micro-nano material dispersion, such as sodium dodecyl sulfate (SDS). The surfactant can significantly decrease the surface tension of the solution and promote uniform dispersion. Experiments have shown that the influence of the surfactant on the self-assembly process of the micro-nano materials can be basically ignored, and its movement in the dispersion will not affect the formation of the self-assembly structure. Therefore, in the technical solution of this embodiment, surfactants can be not used to ensure the environmental protection of the entire preparation process.

[0042] 2. Place the support film on the surface of the micro-nano material dispersion liquid

[0043] In a specific embodiment, a polypropylene film is taken as an example of the support film: Unfold the polypropylene film and gently place it into an open container. The polypropylene film will automatically float on the liquid surface by the surface tension of the liquid and lie flat at the gas-liquid interface of the micro-nano material dispersion liquid. The size of the open container is not limited and is selected according to the area size of the electrothermal film to be prepared. In the case where the support film cannot float due to its own gravity (such as aluminum oxide inorganic film, glass fiber film, etc.), an additional suspension device needs to be added to fix the support film at the gas-liquid interface.

[0044] 3. Heat the micro-nano material dispersion liquid while the support film and the micro-nano material dispersion liquid are in a static state, and the micro-nano material particles self-assemble on the lower surface of the support film to form a micro-nano material self-assembly structure

[0045] Heat the micro-nano material dispersion liquid in the open container according to a preset temperature and a preset time. The heating method is not limited. In a specific embodiment, it is preferably heated by a water bath. The water bath temperature is preset to 40-85 °C, preferably 80 °C; the preset time is 30 minutes to 48 hours. The specific preset time is related to the preset temperature. When the preset temperature is 50 °C, the preset time is 1.5-2 hours; when the preset temperature is 80 °C, the preset time is 20-60 minutes.

[0046] As Figure 2 shown, under the heating of the preset temperature, the water molecules in the micro-nano material dispersion liquid will move towards the gas-liquid interface due to the evaporation of water. At the same time, the convection generated by the movement of water molecules will drive the micro-nano material particles to move towards the support film. Since the diameter of water molecules is smaller than the through-hole diameter of the support film, they will overflow through evaporation from the through-holes; while the diameter of the micro-nano material particles is larger than the through-hole diameter of the support film and will be blocked by the support film, thus adhering to the lower surface of the support film and forming a self-assembly structure.

[0047] 4. Dry the micro-nano material self-assembly structure to obtain a micro-nano material self-assembly film

[0048] The method for drying the micro-nano material self-assembly layer is not limited, and natural air drying or vacuum drying can be selected for drying. In a specific embodiment, the support film attached with the micro-nano material self-assembly layer is taken out from the open container, with the side of the support film attached with the micro-nano material self-assembly structure facing upwards. After drying, a micro-nano material self-assembly film is obtained.

[0049] It should be noted that by adopting the technical solution of this embodiment, the thickness of the prepared large-area self-assembled film can be controlled by the length of the preparation time. The shorter the preparation time, the thinner the generated self-assembled film. Taking the self-assembled film of graphene oxide as an example, the technical solution of this embodiment can make the thickness of the film only 1-2 microns by controlling the preparation duration, while the thickness of the film prepared by the doctor blade method is usually about 100 microns. At the same time, when preparing a large-area self-assembled film, the micro-nano materials grow by layer-by-layer self-assembly, so the thickness of the prepared self-assembled film is more uniform.

[0050] It should be noted that the micro-nano materials exemplified in this embodiment include MXene, carbon nanotubes (CNT) or graphene oxide (GO). Among them, the self-assembled films prepared using MXene and carbon nanotubes have good conductivity, but the nanosheets of graphene oxide are rich in various oxygen-containing groups and have fewer conjugated structures; to achieve better conductivity, the sp hybridization between carbon atoms can be restored through chemical reduction to improve its conductivity. Specifically, the self-assembled film of graphene oxide is placed in a reducing agent solution and heated in a water bath at 80°C for 2 hours, and then the reduced self-assembled film of graphene oxide is taken out and dried. The reducing agent is preferably L-ascorbic acid. 2 The following examples illustrate the parameters and processes for preparing self-assembled films using micro-nano materials:

[0051] The following examples illustrate the parameters and processes for preparing self-assembled films using micro-nano materials:

[0052] (1) Preparation of self-assembled film using MXene

[0053] The support film uses a polyethersulfone membrane with a pore size of 0.22 microns. MXene dispersions with concentrations of 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, and 4 g / L are prepared respectively, ultrasonically dispersed for 30 minutes to be uniform, heated in a water bath at 80°C for 30 minutes, and then taken out and dried.

[0054] (2) Preparation of graphene self-assembled film using GO

[0055] The support film uses a polypropylene membrane with a pore size of 0.22 microns. GO dispersions with concentrations of 0.1 g / L, 0.5 g / L, 1 g / L, 3 g / L, and 5 g / L are prepared respectively, ultrasonically dispersed for 30 minutes to be uniform, heated in a water bath at 80°C for 48 hours, and then taken out and dried. Then the GO self-assembled film is placed in an L-ascorbic acid solution and heated in a water bath at 80°C for 2 hours, and then taken out and dried.

[0056] 5. Connect an electrode sheet to each of the two side edges of the micro-nano material self-assembled film to obtain a micro-nano material electrothermal film assembly

[0057] Level the self-assembled thin film of micro-nano materials, and then connect a copper electrode piece to each of the two side edges of the self-assembled thin film; the connection method is not limited. In a specific embodiment, screw connection or riveting can be used. Preferably, an adhesive method can be used. Apply conductive silver paste on the self-assembled thin film and the copper electrode, and cure the conductive silver paste under ultraviolet irradiation to connect the self-assembled thin film and the electrode piece together to obtain a micro-nano material electrothermal thin film; the thickness of the micro-nano material electrothermal thin film can be controlled to be basically unchanged by using the adhesive method.

[0058] During use, power is supplied to the micro-nano material electrothermal thin film through the copper electrode by a power source for electrothermal heating; either a DC or AC power source can be selected as the power supply.

[0059] Adopting the technical solution of this embodiment, the prepared graphene electrothermal thin film is as Figure 3 shown. Figure 3 The black thin film in Figure 4 is the graphene self-assembled thin film, and a strip-shaped copper electrode is connected to each of the two side edges of the black thin film. When the graphene electrothermal thin film is electrothermally heated, the heating conditions of the electrothermal thin film at different voltages are as

[0060] shown. Using the technical solution provided in the above embodiment, the convection generated by the evaporation of water molecules drives the micro-nano particles to move towards the support film with through holes, and then a micro-nano material thin film can be self-assembled; then the electrode piece is connected to the micro-nano material self-assembled thin film to obtain a micro-nano material electrothermal thin film. In a specific application, a larger-area micro-nano material electrothermal thin film can be prepared by adjusting the size of the support film. The prepared large-area electrothermal thin film can achieve uniform and controllable thickness, and is ultra-light and ultra-thin. No surfactant needs to be added during the whole preparation process, and the process is environmentally friendly.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A preparation method of an ultra-light and ultra-thin nano electrothermal film, characterized in that, Comprising the following steps: Preparing a micro-nano material dispersion liquid, wherein the micro-nano materials include MXene, carbon nanotubes or graphene oxide, and the concentration of the micro-nano material dispersion liquid is 0.1 g / L to 5 g / L; Placing a support membrane with a plurality of through holes on the surface of the micro-nano material dispersion liquid, wherein the aperture of the through holes is larger than the diameter of the solvent molecules and smaller than the diameter of the micro-nano material particles; Heating the micro-nano material dispersion liquid while the support membrane and the micro-nano material dispersion liquid are in a static state, and micro-nano material self-assembled structures are formed on the lower surface of the support membrane; Performing a drying treatment on the micro-nano material self-assembled structures to obtain a micro-nano material self-assembled thin film; Connecting an electrode sheet to each of the two side edges of the micro-nano material self-assembled thin film to obtain a micro-nano material electrothermal thin film.

2. The preparation method of the ultra-light and ultra-thin nano electrothermal film according to claim 1, characterized in that The support membrane includes an organic membrane or an inorganic membrane; the organic membrane includes a polyethersulfone membrane or a polypropylene membrane, and the inorganic membrane is an aluminum oxide inorganic membrane.

3. The method for preparing the ultra-light and ultra-thin nano electrothermal film according to claim 1, characterized in that, The aperture of the through holes is 20 nanometers to 5 micrometers.

4. The preparation method of the ultra-light and ultra-thin nano electrothermal film according to claim 1, wherein When heating the micro-nano material dispersion liquid while the support membrane and the micro-nano material dispersion liquid are in a static state, a water bath method is used for heating, the heating temperature is 40 to 85 °C, and the heating time is 30 minutes to 48 hours.

5. The method for preparing an ultra-light and ultra-thin nano electrothermal film according to claim 1, characterized in that, The drying treatment includes natural air drying or vacuum drying.

6. The method for preparing the ultra-light and ultra-thin nano electrothermal film according to claim 1, characterized in that, The graphene oxide self-assembled thin film needs to be subjected to a reduction treatment.

7. The preparation method of the ultra-light and ultra-thin nano electrothermal film according to claim 6, characterized in that, Performing a reduction treatment on the graphene oxide self-assembled thin film, including: putting the graphene oxide self-assembled thin film into a reducing agent solution and heating it in a water bath at 80 °C for 2 hours.

8. A micro-nano material electrothermal thin film, characterized in that, Prepared by using the method according to any one of claims 1-7.

Images