WO2021046745A1 - Dual-layer thin film driver, preparation method therefor and use thereof - Google Patents

Abstract

A dual-layer thin film driver, a preparation method therefor and a use thereof. The driver comprises a carbon nanotube thin film and a vanadium dioxide nanowire array located on the surface thereof; the length of the vanadium dioxide nanowires is greater than 200 μm, and the angle between the vanadium dioxide nanowires is less than or equal to 10°. The structure of the dual-layer thin film driver is on the centimeter level, and has good driving performance, specificity and processability.

Description

Double-layer film driver and preparation method and application thereof Technical field

This application relates to the field of thin film drivers, and in particular to a double-layer thin film driver and its preparation method and application.

Background technique

At present, in the field of developing micro-medical robots, there is no driver that can meet high frequency, high amplitude and high output power at the same time, and _{the micro-drive based on VO 2} may meet the above requirements at the same time. In recent years, the research on VO ₂ based micro drives has also made preliminary progress.

Armando Rúa used a polycrystalline VO ₂ film and silicon to make a double-layer wafer _{in 2010. Based on the volume and structure changes during the VO 2} phase transition, the double-layer wafer will be significantly bent when the phase transition temperature is reached (see reference: Rúa A, Fernández FE, Sepúlveda N. Bending in VO ₂ -coated microcantilevers suitable for thermally activated actuators[J]. Journal of Applied Physics,2010,107(7):074506). Subsequently, many scientists have successively published related documents. Among them, scholars represented by Professor Wu Junqiao of the Lawrence Berkeley National Laboratory in the United States have carried out a series of outstanding work on dual-chip micro-drives _{based on VO 2 in recent years, such as large-scale, high-speed} Power density micro-drive, VO ₂ micro-drive solid heat engine, and VO ₂ metal chromium double-layer structure miniature torsion catapult. These studies show that _{the double-layer wafer structure of VO 2} film/nanowire and chromium has a good prospect as an excellent long-displacement, high-speed, and powerful micro-actuator. At the same time, it has demonstrated its advantages in microfluidic valves, micro-manipulators, and shape memory structures. And the potential application value of micro-engines (see literature: Liu K, Cheng C, Cheng Z, et al. Giant-amplitude, high-work density microactuators with phase transition activated nanolayer bimorphs[J].Nano letters,2012,12 (12):6302-6308;Ma H,Hou J,Wang X,et al.Flexible,all-inorganic actuators based on vanadium dioxide and carbon nanotube bimorphs[J].Nano letters,2016,17(1):421- 428; Ma H, Hou J, Wang X, et al. Flexible, all-inorganic actuators based on vanadium dioxide and carbon nanotube bimorphs[J].Nano letters,2016,17(1):421-428).

Although the above-mentioned documents disclose some VO ₂ thin-film drivers and their preparation methods, they still have insufficient driving performance of the drivers, and it is impossible to prepare centimeter-level VO ₂ thin-film drivers with good driving performance; therefore, a high-performance VO 2 thin-film driver has been developed. The large-area super-in-line vanadium dioxide nanowire array/carbon nanotube double-layer thin film driver with driving performance, anisotropy and processability and its preparation method are still of great significance.

Summary of the invention

The purpose of this application is to provide a double-layer thin film driver and its preparation method and use. The driver includes a carbon nanotube film and a vanadium dioxide nanowire array on its surface; the length of the vanadium dioxide nanowire is> 200 μm The included angle between the vanadium dioxide nanowires is less than or equal to 10°, and the structure of the double-layer thin film driver of the present application reaches the centimeter level, and has good driving performance, anisotropy and workability.

In order to achieve the purpose of this application, this application adopts the following technical solutions:

In the first aspect, the present application provides a double-layer thin film driver. The driver includes a carbon nanotube film and a vanadium dioxide nanowire array on its surface; the vanadium dioxide nanowire has a length> 200 μm, such as 220 μm, 250μm, 300μm, 500μm or 800μm, etc.; the included angle between the vanadium dioxide nanowires is ≤10°, such as 1°, 2°, 3°, 5°, 7°, 8° or 9°.

The double-layer thin film driver described in the present application is a large-area super in-line vanadium dioxide nanowire array/carbon nanotube double-layer thin film driver. The large area means that the structure of the double-layer film driver is centimeter-level. Taking the double-layer film driver as a rectangle as an example, its length and width are both centimeter-level, and its length is 1-6cm, such as 1.5cm, 2cm , 3cm, 4cm, or 5cm, etc., with a width of 1-3cm, such as 1.5cm, 2cm, or 2.5cm; the super-in-line refers to the angle between the vanadium dioxide nanowires in the vanadium dioxide nanowire array ≤10°. The meaning of the double-layer film is the carbon nanotube film and the vanadium dioxide nanowire array film on the surface. The drive performance of vanadium dioxide is based on its extreme strain along a certain crystal orientation during the phase change process. The orientation of polycrystalline materials in traditional polycrystalline vanadium dioxide drive devices is disordered, so no large strain can be generated. Compared with the traditional polycrystalline vanadium dioxide driving device, the double-layer thin-film driver of the present application has a significantly higher strain value, thereby significantly improving its driving performance.

Preferably, the driving mode of the double-layer thin film driver includes any one or a combination of at least two of heat, light or electricity, and the combination exemplarily includes heat and electricity co-driving, electricity and light co-driving, or heat and light. Total drive and so on.

Taking the thermal drive mode as an example, the working principle of the double-layer thin-film drive is that the super-in-line vanadium dioxide nanowire arrays, as the temperature rises to its phase transition temperature, occur along the c-axis direction of its high-temperature phase (VO ₂ ) Compressive strain in the direction in which the strain occurs in the crystal, that is, thermally induced shrinkage, and the long axis direction of the super-in-line vanadium dioxide nanowires, that is, the corresponding super-in-line array orientation is approximately the same as the c-axis direction of the high-temperature phase. When the temperature rises, the super-in-line vanadium dioxide nanowire array undergoes a phase change and shrinks along the long axis direction of the super-in-line vanadium dioxide nanowire, which can drive the entire thin film driver to the super-in-line vanadium dioxide nanowire array. One side bends, when the temperature decreases, the super-in-line vanadium dioxide nanowire array undergoes a phase change and stretches along the long axis direction of the super-in-line vanadium dioxide nanowire, which can pull the entire thin film driver toward the carbon nanotube film side bending.

The structure of the double-layer film driver described in the present application reaches the centimeter level and has good driving performance; specifically includes: its large driving displacement, the ratio of amplitude to length can reach up to 0.83; high strain, its strain value can reach up to 0.675% ; High theoretical power density, its theoretical power density can reach 3.2J/cm ³ and high response speed, its response rate can reach 15Hz. At the same time, the double-layer film driver described in this application has good anisotropy and processability; by adjusting the angle between the shear direction of the device and the in-line direction of the super-in-line vanadium dioxide nanowire array, the film can be made The drive exhibits different drive behaviors. For example, when the shearing direction is consistent with the in-line direction, it shows normal bending behavior; and when the shearing direction is perpendicular to the in-line direction, the driver can only bend in its width direction (the amplitude is small and can be ignored) ; When the shearing direction is 45° with the in-line direction, the driver is in a spiral shape to achieve twisting and bending.

Preferably, the thickness of the carbon nanotube film is 10-50 μm, such as 12 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm or 45 μm, etc., preferably 15-30 μm.

Preferably, the carbon nanotube film is a multi-wall carbon nanotube film.

Preferably, the thickness of the double-layer thin film driver is 50-100 μm, such as 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, or 95 μm.

In the second aspect, the present application provides a method for manufacturing the double-layer thin film driver as described in the first aspect, and the method includes the following steps:

(1) Mix the vanadium source, oxalic acid and water, and perform hydrothermal treatment to obtain V ₃ O ₇ ·H ₂ O nanowires;

(2) Perform emulsion phase self-assembly _{of the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) to obtain a _{super-in-line V 3} O ₇ ·H ₂ O nanowire array; and

(3) The super-in-line V ₃ O ₇ .H ₂ O nanowire array obtained in step (2) is loaded on a carbon nanotube film, and then annealed to obtain the double-layer film driver.

Preferably, the concentration of oxalic acid in the mixed solution obtained by mixing in step (1) is 0.3-0.5 mg/mL, for example, 0.35 mg/mL, 0.4 mg/mL, or 0.45 mg/mL.

Preferably, the hydrothermal treatment in step (1) is performed in a hydrothermal reactor, and the filling ratio of the hydrothermal method is 50-80%, such as 55%, 60%, 65%, 70% or 75%. The filling ratio means the ratio of the reaction liquid to the volume of the reactor.

Preferably, the vanadium source in step (1) includes vanadium pentoxide.

Preferably, the mass ratio of the vanadium source and oxalic acid in step (1) is (3-5):1, such as 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, or 4.8:1, etc. .

In the preparation process of the present application, the mass ratio of the vanadium source and the oxalic acid is limited to (3-5):1, which is beneficial to the preparation of the V ₃ O ₇ ·H ₂ O nanowires.

Preferably, the temperature of the hydrothermal treatment in step (1) is 240-260°C, such as 242°C, 245°C, 248°C, 250°C, 252°C, 255°C, or 258°C.

Preferably, the time of the hydrothermal treatment in step (1) is 24-36h, such as 25h, 28h, 30h, 32h, 34h or 35h.

Preferably, the method for self-assembly of the emulsion phase in step (2) includes the following steps:

_{(a) The V 3} O ₇ ·H ₂ O nanowires obtained in step (1) are dispersed in water to obtain a suspension, and then a surfactant is added; and

(b) The solution obtained in step (a) is added to a mixed solution of chloroform, water and alcohol, and left to stand to obtain super-in-line V ₃ O ₇ ·H ₂ O nanowires.

_{Preferably, the concentration of the V 3} O ₇ ·H ₂ O nanowires in the suspension in step (a) is (1-3) mg/mL, such as 1.2 mg/mL, 1.5 mg/mL, 1.7 mg/mL, 2mg/mL, 2.2mg/mL, 2.5mg/mL or 2.8mg/mL, etc.

Preferably, the surfactant in step (a) includes polyvinylpyrrolidone.

Preferably, the added amount of the surfactant in step (a) is 3-8% of the suspension mass, such as 4%, 5%, 6% or 7%, etc., preferably 4-6%.

Preferably, the volume ratio of chloroform, water and alcohol in the mixed solution of chloroform, water and alcohol in step (b) is (18-22): (1-4):1; for example, 18:4:1, 18: 3:1, 19:2:1, 20:2:1, 21:1:1, etc., preferably (19-21):(3-4):1.

Preferably, the standing time in step (b) is 1-2h, such as 1.1h, 1.2h, 1.3h, 1.5h, 1.6h or 1.8h.

Preferably, in step (3) _{, the method for loading the super-in-line V 3} O ₇ ·H ₂ O nanowire array obtained in step (2) on a carbon nanotube film includes spreading the carbon nanotube film on a substrate , And then contact the carbon nanotube film with the super-in-line V ₃ O ₇ ·H ₂ O nanowire array; or

The substrate is in contact with the super in-line V ₃ O ₇ ·H ₂ O nanowire array, so that the super in-line V ₃ O ₇ ·H ₂ O nanowire array is loaded on the substrate, and then the carbon nanotube film is attached to the V ₃ O ₇ · H ₂ O nanowire array;

Preferably, the substrate includes a quartz plate.

Preferably, the step (3) before the annealing further includes pretreatment of the carbon nanotube film _{loaded with the super-in-line V 3} O ₇ ·H _{2 O nanowire array.}

Preferably, the pretreatment method includes any one or a combination of at least two of bending, twisting or cutting, and the combination exemplarily includes a combination of bending and twisting, a combination of cutting and twisting, or bending And the combination of shearing and so on.

Through the pretreatment described in this application, followed by annealing, the prepared thin film actuator can be stretched, folded or spiraled at low temperature, and transformed into a bent, unfolded or rotating state at high temperature. This simple design idea also makes it Functional applications in a wider range have become possible.

Preferably, the annealing temperature in step (3) is 450-550°C, such as 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, or 540°C.

Preferably, the annealing treatment in step (3) is performed in an air atmosphere.

Preferably, the pressure of the air atmosphere is 100-500 Pa, such as 110 Pa, 150 Pa, 200 Pa, 250 Pa, 300 Pa, 350 Pa, 400 Pa or 450 Pa.

Preferably, the heating rate of the annealing treatment in step (3) is 20-30°C/min, such as 21°C/min, 22°C/min, 23°C/min, 24°C/min, 25°C/min, 26°C /min, 27°C/min, 28°C/min or 29°C/min, etc., preferably 24-26°C/min.

Preferably, the holding time of the annealing treatment in step (3) is 15-30min, such as 16min, 17min, 18min, 19min, 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min or 29min, etc., preferably For 20-25min.

Preferably, the step (3) further includes cooling after the annealing treatment.

Preferably, the cooling is natural cooling.

As a preferred technical solution of the present application, the preparation method of the double-layer film driver includes the following steps:

(1) Mix vanadium pentoxide and oxalic acid in water at a mass ratio of (3-5):1, and conduct hydrothermal treatment at 240-260℃ for 24-36h to obtain V ₃ O ₇ ·H ₂ O nanometers line;

_{(2) Disperse the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) in water to obtain a suspension. The concentration of the _{V 3} O ₇ ·H _{2 O nanowires in the suspension is (1-3} ) mg/mL, then polyvinylpyrrolidone is added, and the amount of polyvinylpyrrolidone added is 4-6% of the suspension mass;

(3) Add the solution obtained in step (2) to a mixed solution of chloroform, water and alcohol, and let stand for 1-2 hours to obtain a super-in-line V ₃ O ₇ ·H ₂ O nanowire array. The chloroform, water and The volume ratio of chloroform, water and alcohol in the mixed solution of alcohol is (19-21):(3-4):1; and

(4) Load the super-in-line V ₃ O ₇ ·H ₂ O nanowire array obtained in step (3) on the carbon nanotube film, and then anneal it at 450-550°C under an air atmosphere with a pressure of 100-500 Pa. -25min to obtain the double-layer film driver.

In the third aspect, the present application provides the use of the double-layer film driver as described in the first aspect, the double-layer film driver being used in a micro flow valve, a micro manipulator, a shape memory structure, or a micro engine.

Compared with the prior art, this application has the following beneficial effects:

(1) The structure of the double-layer thin film driver described in the present application reaches the centimeter level, and has good driving performance, and its driving performance is close to that of a single crystal vanadium dioxide device (strain is about 1%); specifically, it includes: The driving displacement, the ratio of amplitude to length can reach 0.83; high strain, its strain value can reach up to 0.675%, which is close to single crystal vanadium dioxide device; high theoretical work density, its theoretical work density can reach up to 3.2J/cm ³ And high response speed, its response rate can reach up to 15Hz;

(2) The double-layer film driver described in this application can be driven by any one or a combination of at least two of heat, electricity or light, thereby enriching its application range;

(3) The double-layer film driver described in this application has good anisotropy and workability;

(4) The preparation method of the double-layer film driver described in this application is simple and easy for industrial application;

(5) The double-layer film driver described in this application can change the shape of the driver and the corresponding driving mode by laser cutting or manual cutting, so that it can be used in a wider range of applications, and compared with traditional driving devices, Its operation is simpler.

Description of the drawings

FIG. 1 is a schematic diagram of the process of partially preparing a double-layer thin-film driver according to a specific embodiment of the present application;

2 is a scanning electron micrograph _{of the V 3} O ₇ ·H ₂ O nanowire prepared in Example 1 of the present application;

Fig. 3 is a schematic diagram of the principle of self-assembly of the emulsion phase of the present application;

FIG. 4 is a schematic diagram of the bending of the double-layer film driver described in the present application under thermal driving;

FIG. 5 is an optical picture of the double-layer thin film driver prepared in Example 1 of the present application under thermal driving;

6 is a curve of relative amplitude with temperature of the double-layer thin-film driver prepared in Example 1 of the present application;

7 and 8 are respectively the bending optical pictures of the double-layer thin film driver prepared in Example 1 of the present application without laser irradiation and laser irradiation;

9 and 10 are respectively the bending optical pictures of the double-layer thin film driver prepared in Example 1 of the present application under no current and current excitation;

FIG. 11 is an amplitude curve of the double-layer thin film driver prepared in Example 1 of the present application as a function of current frequency;

FIG. 12 is a schematic diagram of the influence of different shear directions on the driving behavior of the double-layer film driver;

Fig. 13 and Fig. 14 are optical pictures of the driving behavior of the driver under no light and light, respectively, obtained in the 45° shear direction.

detailed description

The technical solutions of the present application will be further explained below through specific implementations. It should be understood by those skilled in the art that the described embodiments are only to help understand the application, and should not be regarded as specific limitations to the application.

A schematic diagram of the process of preparing a double-layer thin film driver in the specific embodiments of the application is shown in Figure 1. The ultra-long V ₃ O ₇ ·H ₂ O nanowires (length> 200 μm) are prepared by hydrothermal method, and then the emulsion phase self-assembly is carried out. , Get the super in-line V ₃ O ₇ ·H ₂ O nanowire array, and then compound the carbon nanotube film to obtain the V ₃ O ₇ ·H ₂ O nanowire array@carbon nanotube double-layer structure, and then anneal to obtain VO ₂ The nanowire array@carbon nanotube double-layer structure, that is, the double-layer thin-film driver described in this application, is then cut in the super-aligned direction to obtain the thin-film driver for testing.

Except for special instructions, the thin film drivers used in the performance test of the embodiment of this application are all cut along the super-order direction. The size of the cut double-layer thin film drive is 5 cm ² , its length is 5 cm, and its width is 1 cm.

The carbon nanotube film partially adopted in the specific embodiments of this application is Deco Island Gold 10-30nm CNT104.

Example 1

The preparation method of the double-layer film driver includes the following steps:

(1) Mix vanadium pentoxide and oxalic acid in water at a mass ratio of 4:1, filling ratio is 60%, and the concentration of oxalic acid in the mixed solution is 0.4mg/ml; conduct hydrothermal treatment at 250℃ 30h to obtain V ₃ O ₇ ·H ₂ O nanowires;

_{(2) Disperse the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) in water to obtain a suspension. _{The concentration of the V 3} O ₇ ·H ₂ O nanowires in the suspension is 2 mg/mL, Then add polyvinylpyrrolidone, the added amount of the polyvinylpyrrolidone is 5% of the suspension mass;

(3) Add the solution obtained in step (2) into a 6cm×6cm×6cm cubic glass container, which contains a mixed solution of chloroform, water and alcohol, and let it stand for 2h to obtain super-in-line V ₃ O _7. H ₂ O nanowire array, the volume ratio of chloroform, water and alcohol in the mixed solution of chloroform, water and alcohol is 20:3:1;

(4) Spread the multi-walled carbon nanotube film with a thickness of 20 μm on the quartz plate, and use the quartz plate attached with the multi-walled carbon nanotube film to collect the super-in-line V ₃ O ₇ in the solution obtained in step (3). The H ₂ O nanowire array makes the carbon nanotube film closely contact the super in-line V ₃ O ₇ ·H ₂ O nanowire array; then it is annealed at 500°C for 20 minutes in an air atmosphere with a pressure of 300 Pa, and then naturally cooled to room temperature , The V ₃ O ₇ ·H ₂ O nanowires are converted into VO ₂ nanowires to obtain the double-layer thin film driver.

The ratio of the amplitude to the length of the double-layer film driver prepared in this embodiment is 0.83; the strain value is 0.675%, the theoretical work density is 3.2 J/cm ³ , and the response rate is 15 Hz.

_{The scanning electron micrograph of the V 3} O ₇ ·H ₂ O nanowires prepared in this embodiment is shown in Fig. 2, and it can be seen from the figure that _{the length of the V 3} O ₇ ·H ₂ O nanowires is greater than 200 μm.

The flow diagram of the emulsion phase self-assembly described in the present application is shown in Figure 3. It can be seen from the figure that the steps of self-assembly of the emulsion phase described in the present application include adding the V ₃ O ₇ ·H ₂ O nanowire suspension to the polymer Vinylpyrrolidone was used to obtain the V ₃ O ₇ ·H ₂ O nanowire mixed emulsion, which was then added to the mixed liquid of chloroform, water and alcohol, and the mixture was shaken and mixed and then stood still to obtain the super-in-line V ₃ O ₇ ·H ₂ O nanowire array.

A schematic diagram of the bending of the double-layer film driver described in the present application under thermal drive is shown in Fig. 4. It can be seen from the figure that the double-layer film driver can be excited by heat, and the VO ₂ layer shrinks at high temperatures to generate bending power.

The optical picture of the double-layer thin film driver prepared in Example 1 of the present application under thermal driving and the relative amplitude curve of the thin film driver with temperature are shown in Figures 5 and 6, respectively. Combining the above two figures, it can be seen that the prepared double layer The ratio of the amplitude to the length of the thin film actuator is 0.83; the strain value is 0.675%, and the theoretical work density can be calculated to be 3.2J/cm ³ .

The bending optical pictures of the double-layer thin film driver prepared in Example 1 of the present application without laser irradiation and under laser irradiation are shown in Figs. 7 and 8, respectively. It can be seen from the figures that the double-layer thin film driver can be excited by light.

The bending optical pictures of the double-layer thin film driver prepared in Example 1 of the present application under no current and current excitation are shown in Figs. 9 and 10, and it can be seen from the figures that the double-layer thin film driver can be excited by current.

The amplitude curve of the double-layer thin-film driver prepared in Example 1 of the present application with the current frequency is shown in FIG. 11. It can be seen from the figure that the double-layer thin-film driver can maintain a relatively high movement frequency under current excitation.

The schematic diagram of the influence of different shearing directions on the drive behavior of the drive is shown in Figure 12. It can be seen from the figure that when the shearing direction is the same as the in-line direction (0°), it shows normal bending behavior; and when the shearing direction When it is perpendicular to the in-line direction (90°), the driver can only bend in its width direction; when the shearing direction is 45° to the in-line direction, the driver is in a spiral shape to achieve twisting and bending.

The optical pictures of the drive behavior of the thin film driver prepared in this embodiment along the 45° shear direction under no light and light are shown in Figure 13 and Figure 14. It can be seen from the figure that the double-layer thin film drive passes through 45°. Shear preparation realizes twisting and bending.

Example 2

The preparation method of the double-layer film driver includes the following steps:

(1) Mix vanadium pentoxide and oxalic acid in water at a mass ratio of 3:1, with a filling ratio of 50%, and the concentration of oxalic acid in the mixed solution obtained by the mixing is 0.4 mg/mL; at 240°C Perform hydrothermal treatment for 36 hours to obtain V ₃ O ₇ ·H ₂ O nanowires;

_{(2) Disperse the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) in water to obtain a suspension. _{The concentration of the V 3} O ₇ ·H ₂ O nanowires in the suspension is 3 mg/mL, Then add polyvinylpyrrolidone, the added amount of the polyvinylpyrrolidone is 4% of the suspension mass;

(3) Add the solution obtained in step (2) into a 6cm×6cm×6cm cubic glass container, which contains a mixed solution of chloroform, water and alcohol, and let it stand for 1 hour to obtain a super-in-line V ₃ O _7. H ₂ O nanowire array, the volume ratio of chloroform, water and alcohol in the mixed solution of chloroform, water and alcohol is 19:2.5:1;

(4) Spread the multi-walled carbon nanotube film with a thickness of 30 μm on the quartz plate, and use the quartz plate attached with the multi-walled carbon nanotube film to collect the super-in-line V ₃ O ₇ in the solution obtained in step (3). The H ₂ O nanowire array makes the carbon nanotube film closely contact the super-in-line V ₃ O ₇ ·H ₂ O nanowire array; then it is annealed at 550°C for 25 minutes in an air atmosphere with a pressure of 100 Pa, and then naturally cooled to room temperature , The V ₃ O ₇ ·H ₂ O nanowires are converted into VO ₂ nanowires to obtain the double-layer thin film driver.

Example 3

The preparation method of the double-layer film driver includes the following steps:

(1) Mix vanadium pentoxide and oxalic acid in a mass ratio of 5:1, and the filling ratio is 80%. The concentration of oxalic acid in the mixed solution obtained by the mixing is 0.4 mg/ml; Heat treatment for 24 hours to obtain V ₃ O ₇ ·H ₂ O nanowires;

_{(2) Disperse the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) in water to obtain a suspension, and the _{concentration of the V 3} O ₇ ·H ₂ O nanowires in the suspension is 1 mg/mL, Then add polyvinylpyrrolidone, the added amount of the polyvinylpyrrolidone is 6% of the suspension mass;

(3) Add the solution obtained in step (2) into a 6cm×6cm×6cm cubic glass container containing a mixed solution of chloroform, water and alcohol, and let it stand for 1.5h to obtain a super-in-line V ₃ O ₇ ·H ₂ O nanowire array, the volume ratio of chloroform, water and alcohol in the mixed solution of chloroform, water and alcohol is 21:1.5:1;

(4) Use a quartz plate to collect the super-in-line V ₃ O ₇ ·H ₂ O nanowire array in the solution obtained in step (3), and then lay a 50 μm thick multi-walled carbon nanotube film on the super-in-line V 3 O 7 ·H 2 O nanowire array. _{On the 3} O ₇ ·H ₂ O nanowire array, the carbon nanotube film is _{brought into close contact with the super-in-line V 3} O ₇ ·H ₂ O nanowire array. The composite film is removed and dried in an environment of 60°C; After annealing at 450°C for 25 minutes in an air atmosphere with a pressure of 500 Pa, the temperature is naturally lowered to room temperature, and the V ₃ O ₇ ·H ₂ O nanowires are converted into VO ₂ nanowires to obtain the double-layer thin film driver.

Example 4

The difference between this embodiment and Embodiment 2 is that the annealing temperature in step (4) is replaced with 450° C., and other conditions are completely the same as those in Embodiment 2.

Example 5

The difference between this embodiment and Embodiment 2 is that the annealing temperature in step (4) is replaced with 600° C., and other conditions are completely the same as those in Embodiment 2.

Example 6

The difference between this embodiment and embodiment 2 is that the annealing temperature in step (4) is replaced with 400° C., and other conditions are completely the same as those in embodiment 2.

Example 7

The difference between this embodiment and the embodiment 2 is that the air pressure of the annealing treatment in step (4) is replaced with 500 Pa, and the other conditions are completely the same as that of the embodiment 2.

Example 8

The difference between this embodiment and Embodiment 2 is that the air pressure of the annealing treatment in step (4) is replaced with 1000 Pa, and the other conditions are completely the same as those of Embodiment 2.

Example 9

The difference between this embodiment and the embodiment 2 is that the air pressure of the annealing treatment in step (4) is replaced with 50 Pa, and the other conditions are completely the same as that of the embodiment 2.

Example 10

Compared with Example 1, this comparative example does not add polyvinylpyrrolidone in step (2), and the other conditions are completely the same as those of Example 1.

Example 11

This comparative example is compared with Example 1, the mixed solution in step (3) is replaced with a chloroform solution, and other conditions are completely the same as those of Example 1.

Performance Testing:

Amplitude to length ratio test method: first measure the actual size of the double-layer film driver, and then use Photoshop software to compare the different states before and after the strain before shooting, and calculate the amplitude and length ratio through the scale.

The test method of strain value described in the detailed implementation section includes: after obtaining the magnitude of the amplitude, then calculating the magnitude of the strain value (for the calculation method, please refer to the literature: Lu C, Yang Y, Wang J, et al. High-performance graphdiyne -based electrochemical actuators[J].Nature communications,2018,9(1):752.).

Test method of theoretical work density: calculate the power density after obtaining the strain value (for the calculation method, please refer to the literature: Lu C, Yang Y, Wang J, et al. High-performance graphdiyne-based electrochemical actuators[J]. Nature communications ,2018,9(1):752.).

Response rate test method: use silver paste on both ends of the double-layer film driver to paste on the quartz glass, and then slowly increase the frequency from 0 while maintaining a voltage of 7V, until the amplitude change is not obvious. Then take screenshots of videos and use Photoshop software to analyze the corresponding frequencies under different amplitudes.

The test results of the strain value, amplitude to length ratio, theoretical work density and response rate of the double-layer thin film actuators prepared in Examples 1-11 are shown in Table 1:

Table 1

To

Strain value,%

Amplitude to length ratio

Theoretical work density,

Response rate, Hz

To	To	To	J/cm 3	To
Example 1	0.675	0.83	3.2	15
Example 2	0.5	0.73	1.75	13
Example 3	0.6	0.79	2.5	16
Example 4	0.1	0.12	0.07	5
Example 5	0	0	0	0
Example 6	0	0	0	0
Example 7	0.4	0.65	1.12	11
Example 8	0	0	0	0
Example 9	0	0	0	0
Example 10	0.2	0.3	0.28	10
Example 11	0.15	0.25	0.16	11

It can be seen from the above table that compared with Examples 1, 4-6, it can be seen that when the annealing temperature of step (4) in the method described in this application is 450-550°C, the strain value of the double-layer thin film driver prepared therefrom is Both are relatively high, up to 0.675%, the ratio of amplitude to length is up to 0.83, the theoretical work density is up to 3.2J/cm ³ , and the response rate is up to 15Hz.

Comparing Examples 1, 7-9, it can be seen that when the air pressure of the annealing treatment in step (4) of the method described in this application is 100-500 Pa, the strain values of the double-layer thin film actuators prepared therefrom are all higher and the highest It can reach 0.675%, the ratio of amplitude to length can reach 0.83, the theoretical work density can reach 3.2J/cm ³ , and the response rate can reach 15Hz.

Comparing Examples 1 and 10, it can be seen that the addition of polyvinylpyrrolidone in step (2) of the present application can significantly improve the performance of the prepared double-layer film driver.

Comparing Examples 1 and 11, it can be seen that the mixed solution of chloroform, water and alcohol used in step (3) of the present application has significantly better performance than that of pure chloroform.

The applicant declares that the above are only specific implementations of this application, but the scope of protection of this application is not limited to this, and those skilled in the art should understand that any person skilled in the art disclosed in this application Any changes or replacements that can be easily conceived within the technical scope fall within the scope of protection and disclosure of this application.

Claims (15)

1. A double-layer film driver, comprising a carbon nanotube film and a vanadium dioxide nanowire array on the surface; the length of the vanadium dioxide nanowire is> 200 μm, and the angle between the vanadium dioxide nanowires is less than or equal to 10 °.
2. The double-layer thin film driver of claim 1, wherein the driving mode of the double-layer thin film driver includes any one or a combination of at least two of heat, light or electricity.
3. The double-layer film driver according to claim 1, wherein the thickness of the carbon nanotube film is 10-50 μm, preferably 15-30 μm; and

   The thickness of the double-layer film driver is 50-100 μm.
4. The method for manufacturing a double-layer thin film driver according to any one of claims 1 to 3, wherein the method comprises the following steps:

   (1) Mix the vanadium source, oxalic acid and water, and perform hydrothermal treatment to obtain V ₃ O ₇ ·H ₂ O nanowires;

   (2) Perform emulsion phase self-assembly _{of the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) to obtain a _{super-in-line V 3} O ₇ ·H ₂ O nanowire array; and

   (3) The super-in-line V ₃ O ₇ .H ₂ O nanowire array obtained in step (2) is loaded on a carbon nanotube film, and then annealed to obtain the double-layer film driver.
5. The method of claim 4, wherein the vanadium source in step (1) comprises vanadium pentoxide;

   Preferably, the mass ratio of the vanadium source and oxalic acid in step (1) is (3-5):1.
6. The method according to claim 4, wherein the temperature of the hydrothermal treatment in step (1) is 240-260°C;

   Preferably, the time of the hydrothermal treatment in step (1) is 24-36h.
7. The method according to any one of claims 4-6, wherein the method for self-assembly of the emulsion phase in step (2) comprises the following steps:

   _{(a) The V 3} O ₇ ·H ₂ O nanowires obtained in step (1) are dispersed in water to obtain a suspension, and then a surfactant is added; and

   (b) Add the solution obtained in step (a) to a mixed solution of chloroform, water and alcohol, stir and then stand still to obtain super-in-line V ₃ O ₇ ·H ₂ O nanowires.
8. The method according to claim 7, wherein _{the concentration of the V 3} O ₇ ·H ₂ O nanowires in the suspension in step (a) is (1-3) mg/mL.
9. 8. The method of claim 7, wherein the surfactant in step (a) comprises polyvinylpyrrolidone;

   Preferably, the added amount of the surfactant in step (a) is 3-8% of the suspension mass, preferably 4-6%.
10. The method according to any one of claims 7-9, wherein the volume ratio of chloroform, water and alcohol in the mixed solution of chloroform, water and alcohol in step (b) is (18-22): (1- 4):1; preferably (19-21):(3-4):1;

    Preferably, the standing time in step (b) is 1-2h.
11. The method according to any one of claims 4-10, wherein, in step (3), the super-in-line V ₃ O ₇ ·H ₂ O nanowire array obtained in step (2) is loaded on a carbon nanotube film The above method includes laying the carbon nanotube film flat on the substrate, and then contacting the carbon nanotube film with the super in-line V ₃ O ₇ ·H ₂ O nanowire array; or

    The substrate is in contact with the super in-line V ₃ O ₇ ·H ₂ O nanowire array, so that the super in-line V ₃ O ₇ ·H ₂ O nanowire array is loaded on the substrate, and then the carbon nanotube film is attached to the V ₃ O ₇ · H ₂ O nanowire array.
12. The method according to claim 4, wherein, before the annealing in step (3), it further comprises pretreating the carbon nanotube film _{loaded with the super in-line V 3} O ₇ ·H _{2 O nanowire array;}

    Preferably, the pretreatment method includes any one or a combination of at least two of bending, twisting or cutting.
13. The method of claim 4, wherein the annealing temperature in step (3) is 450-550°C;

    Preferably, the annealing treatment in step (3) is performed in an air atmosphere;

    Preferably, the pressure of the air atmosphere is 100-500 Pa;

    Preferably, the heating rate of the annealing treatment in step (3) is 20-30°C/min; preferably 24-26°C/min;

    Preferably, the holding time of the annealing treatment in step (3) is 15-30 min, preferably 20-25 min;

    Preferably, the step (3) further includes cooling after the annealing treatment;

    Preferably, the cooling is natural cooling.
14. The method according to any one of claims 4-13, wherein the method comprises the following steps:

    (1) Mix vanadium pentoxide and oxalic acid in water at a mass ratio of (3-5):1, and conduct hydrothermal treatment at 240-260℃ for 24-36h to obtain V ₃ O ₇ ·H ₂ O nanometers line;

    _{(2) Disperse the V 3} O ₇ ·H ₂ O nanowires obtained in step (1) in water to obtain a suspension. The concentration of the _{V 3} O ₇ ·H _{2 O nanowires in the suspension is (1-3} ) mg/mL, then polyvinylpyrrolidone is added, and the amount of polyvinylpyrrolidone added is 4-6% of the suspension mass;

    (3) Add the solution obtained in step (2) to a mixed solution of chloroform, water and alcohol, and let stand for 1-2 hours to obtain a super-in-line V ₃ O ₇ ·H ₂ O nanowire array. The chloroform, water and The volume ratio of chloroform, water and alcohol in the mixed solution of alcohol is (19-21):(3-4):1; and

    (4) Load the super-in-line V ₃ O ₇ ·H ₂ O nanowire array obtained in step (3) on the carbon nanotube film, and then anneal it at 450-550°C under an air atmosphere with a pressure of 100-500 Pa. -25min to obtain the double-layer film driver.
15. The use of the double-layer film actuator according to any one of claims 1 to 3, which is used in a micro flow valve, a micro manipulator, a shape memory structure or a micro engine.

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