阅读说明：本技术 一种高耐久性二氧化钒薄膜的制备方法 (Preparation method of high-durability vanadium dioxide film ) 是由 田守勤 陆忠成 张勇强 杨鑫伟 于 2019-10-25 设计创作，主要内容包括：本发明公开了一种高耐久性二氧化钒薄膜的制备方法。包括以下步骤：将介孔二氧化钒粉体加入到醋酸锌的乙醇溶液中超声-磁力搅拌,同时缓慢滴加氨水至溶液有白色沉淀产生,转移至马弗炉中,加热得到高耐久性复合粉体；将聚乙烯吡咯烷酮与所得复合粉体置于二氧化锆球磨罐中,加入乙醇进行混合球磨,所得球磨液离心,取上层悬浮液干燥得到粉体,将粉体与无水乙醇混合制备得到镀膜液,利用旋涂法镀膜得到高耐久性二氧化钒薄膜。本发明制备得到的高耐久性二氧化钒薄膜,相对于传统的二氧化钒薄膜,具有很好的耐久性,同时拥有较好的太阳光调制效率和较高的可见光透过率。(The invention discloses a preparation method of a high-durability vanadium dioxide film. The method comprises the following steps: adding the mesoporous vanadium dioxide powder into an ethanol solution of zinc acetate, performing ultrasonic-magnetic stirring, slowly dropwise adding ammonia water until white precipitate is generated in the solution, transferring the solution into a muffle furnace, and heating to obtain high-durability composite powder; putting polyvinylpyrrolidone and the obtained composite powder into a zirconium dioxide ball milling tank, adding ethanol for mixing and ball milling, centrifuging the obtained ball milling liquid, taking the upper layer suspension for drying to obtain powder, mixing the powder with absolute ethanol to prepare coating liquid, and coating by using a spin coating method to obtain the high-durability vanadium dioxide film. Compared with the traditional vanadium dioxide thin film, the high-durability vanadium dioxide thin film prepared by the invention has good durability, and simultaneously has good solar light modulation efficiency and high visible light transmittance.)

1. A preparation method of a high-durability vanadium dioxide film is characterized by comprising the following steps:

(1) hydrothermal method for preparing mesoporous vanadium dioxide powder

Mixing a precursor vanadium pentoxide powder with oxalic acid, adding deionized water, mixing and stirring at 60-90 ℃ and reacting to dark blue; cooling to room temperature, adding ethylene glycol, continuously stirring, and slowly dropwise adding ammonia water until the solution is alkaline; transferring the cotton into a reaction kettle filled with a cotton template agent, preserving heat for 20-24 h at 150-190 ℃ to obtain cotton attached with vanadium dioxide particles, washing and drying; firing at 400-470 ℃ to obtain vanadium pentoxide powder with a cotton framework, and placing in a tubular vacuum furnace for annealing treatment to obtain mesoporous vanadium dioxide powder;

(2) zinc ion solution treated mesoporous vanadium dioxide powder

Adding the obtained mesoporous vanadium dioxide powder into an ethanol solution of zinc acetate, carrying out ultrasonic-magnetic stirring, slowly dropwise adding ammonia water until white precipitate is generated in the solution, transferring the solution into a muffle furnace, and heating to obtain high-durability composite powder;

(3) preparation of high-durability vanadium dioxide film

Putting polyvinylpyrrolidone and the obtained composite powder into a zirconium dioxide ball milling tank, adding ethanol for mixing and ball milling, centrifuging the obtained ball milling liquid, taking the upper layer suspension for drying to obtain powder, mixing the powder with absolute ethanol to prepare coating liquid, and coating by using a spin coating method to obtain the high-durability vanadium dioxide film.

2. The method for preparing a highly durable vanadium dioxide film according to claim 1, wherein the molar ratio of oxalic acid to vanadium pentoxide in step (1) is 3: (1-2).

3. The method for preparing a vanadium dioxide thin film with high durability according to claim 1, wherein the atomic ratio of vanadium to zinc in the step (2) is 100: (4-12).

4. The method according to claim 1, wherein the concentration of the mesoporous vanadium dioxide powder in the step (2) is 0.005 g/mL-0.02 g/mL.

5. The method for preparing the high-durability vanadium dioxide thin film according to claim 1, wherein ammonia water is added dropwise in the step (2) until the pH value of the solution is 7-9.

6. The method for preparing the high-durability vanadium dioxide film according to claim 1, wherein the heating temperature of the muffle furnace in the step (2) is 100-200 ℃ and the time is 1-3 h.

7. The method for preparing the high-durability vanadium dioxide film as claimed in claim 1, wherein the mass ratio of the polyvinylpyrrolidone in the step (3) to the composite powder is 1: (1.5-2).

8. The method for preparing the high-durability vanadium dioxide film as claimed in claim 1, wherein the mass ratio of the composite powder obtained in the step (3) to the absolute ethyl alcohol is 1: (7-10).

9. The method for preparing the high-durability vanadium dioxide thin film according to claim 1, wherein the spin coating speed of the spin coating film in the step (3) is 800-1500 r/min.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a preparation method of a high-durability vanadium dioxide film.

Background

The vanadium dioxide material is a metal oxide with phase change property, and shows unique reversible metal insulator phase change, the phase change can cause the electrical, magnetic and optical properties of the vanadium dioxide to change suddenly, the vanadium dioxide can be changed from a monoclinic semiconductor phase to a rutile metal phase at the temperature higher than 68 ℃, and the vanadium dioxide can be changed reversibly at the temperature lower than 68 ℃. The vanadium dioxide phase transition process is accompanied with the sudden change of the resistivity and the infrared transmittance, and the like, so that the vanadium dioxide film has wide application prospect as an intelligent window coating material.

Most of the current researches mainly focus on how to improve the visible light transmittance and the solar light modulation capability of the vanadium dioxide thin film and reduce the phase transition temperature to the degree close to room temperature. For the transmittance of the film, the vanadium dioxide has strong absorption to sunlight with a wavelength of less than 500nm, so that the transmittance of the vanadium dioxide film is low, generally less than 50%, and the sunlight transmittance required by the lighting of a building is usually higher than 60%. Therefore, the main means for increasing the transmittance at present include element doping, film structure design and the application of antireflection films. For improving the solar light modulation capability, the literature reports that the control of the crystallinity of vanadium dioxide and other vanadium valence states in the film has a promoting effect on improving the solar light modulation efficiency. For how to reduce the phase transition temperature, a common regulation and control means is to reduce the phase transition temperature by an atom doping mode, and in addition, the interface stress generated in the vanadium dioxide film can also reduce the phase transition temperature.

However, practical application of vanadium dioxide smart window films faces another significant challenge: durability of the film. If the vanadium dioxide film applied to the glass curtain wall is influenced by a severe environment for a long time, the vanadium dioxide particles on the surface of the film can be slowly oxidized into more stable vanadium pentoxide, so that the thermochromism performance of the film is reduced. Therefore, the improvement of the oxidation resistance of the vanadium dioxide film is also an important content, and in the past, researchers have designed a protective layer coating the vanadium dioxide particle structure to achieve the improvement of the oxidation resistance.

Disclosure of Invention

The invention aims to provide a preparation method of a high-durability vanadium dioxide film, and aims to solve the problems of environmental durability and incapability of meeting the requirements of high visible light transmittance and high sunlight modulation efficiency of the vanadium dioxide film.

In order to achieve the purpose, the technical scheme is as follows:

a preparation method of a high-durability vanadium dioxide film comprises the following steps:

(1) hydrothermal method for preparing mesoporous vanadium dioxide powder

Mixing a precursor vanadium pentoxide powder with oxalic acid, adding deionized water, mixing and stirring at 60-90 ℃ and reacting to dark blue; cooling to room temperature, adding ethylene glycol, continuously stirring, and slowly dropwise adding ammonia water until the solution is alkaline; transferring the cotton into a reaction kettle filled with a cotton template agent, preserving heat for 20-24 h at 150-190 ℃ to obtain cotton attached with vanadium dioxide particles, washing and drying; firing at 400-470 ℃ to obtain vanadium pentoxide powder with a cotton framework, and placing in a tubular vacuum furnace for annealing treatment to obtain mesoporous vanadium dioxide powder;

(2) zinc ion solution treated mesoporous vanadium dioxide powder

Adding the obtained mesoporous vanadium dioxide powder into an ethanol solution of zinc acetate, carrying out ultrasonic-magnetic stirring, slowly dropwise adding ammonia water until white precipitate is generated in the solution, transferring the solution into a muffle furnace, and heating to obtain high-durability composite powder;

(3) preparation of high-durability vanadium dioxide film

Putting polyvinylpyrrolidone and the obtained composite powder into a zirconium dioxide ball milling tank, adding ethanol for mixing and ball milling, centrifuging the obtained ball milling liquid, taking the upper layer suspension for drying to obtain powder, mixing the powder with absolute ethanol to prepare coating liquid, and coating by using a spin coating method to obtain the high-durability vanadium dioxide film.

According to the scheme, the molar ratio of oxalic acid to vanadium pentoxide in the step (1) is 3: (1-2).

According to the scheme, the atomic ratio of vanadium to zinc in the step (2) is 100: (4-12).

According to the scheme, the concentration of the mesoporous vanadium dioxide powder in the step (2) is 0.005 g/mL-0.02 g/mL.

According to the scheme, ammonia water is dripped in the step (2) until the pH value of the solution is 7-9.

According to the scheme, the heating temperature of the muffle furnace in the step (2) is 100-200 ℃, and the time is 1-3 h.

According to the scheme, the mass ratio of the polyvinylpyrrolidone in the step (3) to the obtained composite powder is 1: (1.5-2).

According to the scheme, the mass ratio of the composite powder obtained in the step (3) to the absolute ethyl alcohol is 1: (7-10).

According to the scheme, the spin coating speed of the spin coating method in the step (3) is 800-1500 r/min.

The invention discovers that the following components are obtained in the test of the thermochromic performance of the thin film for 60 days continuously: the thermochromic efficiency of the film is not reduced along with the increase of the number of days of the film standing time, but is obviously increased on the contrary, which shows that the zinc ion solution treatment method plays a role in protecting vanadium dioxide particles, reduces the oxidation effect of the environment and improves the durability of the film.

The invention has the following beneficial effects:

the method has the advantages of simple equipment, easy operation, low raw material cost and relatively independent preparation steps, and is suitable for large-scale production.

Compared with the traditional vanadium dioxide thin film, the high-durability vanadium dioxide thin film prepared by the invention has good durability, and simultaneously has good solar light modulation efficiency and high visible light transmittance.

The invention discovers that the following components are obtained in the test of the thermochromic performance of the thin film for 60 days continuously: the thermochromic efficiency of the film is not reduced along with the increase of the days of the film standing time, but is obviously increased on the contrary, which shows that the zinc ion solution treatment method plays a role in protecting vanadium dioxide particles and reducing the oxidation of the environment, thereby improving the durability of the film.

Drawings

FIG. 1: XRD pattern of the highly durable composite powder obtained in example 1.

FIG. 2: transmittance vs. wavelength for the highly durable vanadium dioxide film obtained in example 1.

FIG. 3: transmittance-wavelength curve of the high-durability vanadium dioxide thin film obtained in example 2.

Detailed Description

The following examples further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.