Airflow-assisted nanowire material directional arrangement method and device

Abstract

This application discloses an airflow-assisted method and apparatus for the directional arrangement of nanowire materials. The method and apparatus employ an axial flow fan and an ion fan, mount a substrate on a rotating platform, activate a liquid dispensing device, the axial flow fan, and the ion fan, and apply a coating to the surface of the high-speed rotating substrate to form a wet film. The airflow-assisted method and apparatus for the directional arrangement of nanowire materials employs an axial flow fan to generate downward spiral wind, which, under the action of air viscosity, causes the linear materials to be oriented in the direction of the wind speed. The ion fan generates upward wind to reduce the excessive downward wind speed generated by the axial flow fan. Once the linear materials are deposited on the substrate surface, the high-speed rotation generates a sufficiently large centrifugal force, causing the linear materials to be oriented under the action of friction and centrifugal forces.

Description

Technical Field

[0001] The present invention relates to the field of film coating technology, and in particular to an airflow-assisted nano-linear material directional arrangement method and device. Background Art

[0002] Conductive films are widely used in fields such as transparent heating, transparent electrodes for solar cells, color-changing glass, and flexible electronic devices. With the rapid advancement of technology, flexible conductive films are increasingly being used in areas such as electronic skin and medical health monitoring. For example, oriented silver nanowire conductive films exhibit significant advantages for the following reasons: First, they possess excellent flexibility and are expected to replace traditional indium tin oxide conductive films; second, the regularly arranged silver nanowire conductive network effectively reduces the number of nanowire cross-junctions, thereby lowering junction resistance and increasing failure voltage.

[0003] In the process of preparing transparent conductive films with oriented silver nanowires, achieving precise placement of the nanowires remains a significant challenge. Currently, among existing technologies for oriented nanowire materials: While the capillary force method produces oriented silver nanowire conductive films with excellent directional effects, its production efficiency is low, making it difficult to meet industrial demand. The water bath pulling method can also produce silver nanowire conductive films with excellent directional effects. However, this method requires the silver nanowire solution to form a convection environment and the substrate material to be hydrophilic, resulting in demanding process conditions. While the shear coating method can produce large-area, well-oriented silver nanowire conductive films, it requires high-speed stirring of the silver nanowire solution, which can easily lead to breakage of the silver nanowires. Furthermore, the boundary effects of the container wall can also affect the directional alignment. Therefore, achieving high efficiency and quality in the preparation of conductive films with directional alignment characteristics remains a significant challenge. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method and device for directional arrangement of nano-linear materials assisted by airflow, aiming to solve the problem of how to efficiently and high-quality prepare conductive films with directional arrangement characteristics.

[0005] To achieve the above objectives, the present invention provides an airflow-assisted method for aligning nanowire materials, comprising:

[0006] S1. Setting a liquid output device, an axial flow fan, and an ion fan, wherein the axial flow fan is located below the output end of the liquid output device, the ion fan is located below the axial flow fan, the middle portion of the axial flow fan is a rotating platform, the axial flow fan generates a downward spiral airflow, and the ion fan generates an upward airflow;

[0007] S2. preparing a linear material solution and transferring it to the liquid output device, wherein the liquid output device is used to output the linear material solution in the form of droplets;

[0008] S3, mounting a substrate on the rotating platform, with the output end of the liquid output device and the substrate spaced vertically at a distance of 0.2-3 cm;

[0009] S4. Starting the liquid output device, the axial flow fan, and the ion fan to form a wet film on the surface of the substrate rotating at high speed, wherein the rotation speed of the axial flow fan is 2500-3500 rpm, and the wind speed generated by the ion fan is 2.5-4.2 m / s;

[0010] S5. Stop the operation of the liquid output device, the axial flow fan, and the ion fan, remove the substrate, and perform heat treatment to form a conductive film.

[0011] Furthermore, the step S2 includes:

[0012] S1.1 constructs a physical model, takes increasing the circumferential airflow velocity of the axial flow fan and decreasing the vertical airflow velocity above the axial flow fan as optimization goals, and simulates and calculates the operating parameters of the axial flow fan and the ion fan.

[0013] Furthermore, the middle part of the axial flow fan is a fan assembly, and the fan assembly includes a central axis and a fan blade portion arranged circumferentially of the central axis. In the step S1.1: the optimization target also includes the proportion of droplets falling onto the substrate, and the operating parameters of the axial flow fan include the dimensions of the central axis and the fan blade portion.

[0014] Furthermore, the step S4 includes:

[0015] Starting and adjusting the axial flow fan to a set speed;

[0016] Starting and adjusting the operation of the ion fan according to the wind speed above the axial flow fan;

[0017] The liquid output device is started to apply liquid on the surface of the substrate rotating at a high speed to form a wet film.

[0018] Furthermore, in the step S3, the material of the substrate is one of inorganic non-metal, metal and polymer.

[0019] Furthermore, the length of the linear material in the linear material solution is 20 to 40 microns, and the diameter is 20 to 100 nanometers.

[0020] Furthermore, the liquid output device is an electric pipette or a peristaltic pump.

[0021] Furthermore, in step S2, the linear material solution is prepared by mixing a linear material solution stock solution with a concentration of 5-15 mg / ml, ethanol and isopropanol in a volume ratio of 1-2:0.2-1:0.8-2.2.

[0022] The present invention further provides a device for use in the above-mentioned airflow-assisted nanowire material directional arrangement method, comprising:

[0023] base;

[0024] a liquid output device, arranged at the upper portion of the base in the height direction;

[0025] an axial flow fan, correspondingly disposed below the output end of the liquid output device, wherein the middle portion of the axial flow fan is a rotating platform, wherein the upper portion of the rotating platform is used to mount an external substrate;

[0026] The ion fan is vertically spaced apart from the axial flow fan, wherein the axial flow fan generates a downward spiral airflow in the space above the axial flow fan, and the ion fan generates an upward airflow in the space above the axial flow fan.

[0027] Furthermore, a first wind speed sensor for testing the circumferential wind speed is provided at the periphery of the space above the axial flow fan, and a second wind speed sensor for testing the vertical wind speed is provided at the space above the axial flow fan.

[0028] The airflow-assisted nanowire material alignment method and apparatus provided by the present invention uses an axial fan to generate downward spiraling air. The viscous force of the air aligns the nanowires in the direction of the wind speed. An ion fan generates upward airflow to reduce the excessive downward air velocity generated by the axial fan. Once the nanowires are deposited on the substrate surface, the high-speed rotation generates a sufficiently large centrifugal force, which aligns the nanowires under the influence of friction and centrifugal forces.

[0029] Specific beneficial effects include:

[0030] 1. Precise control of nanowire materials: Compared with other methods for preparing conductive films composed of nanowire materials, precise control of the arrangement direction of nanowire materials can be achieved by adjusting the speed of the axial fan and the ion fan, as well as the distance between the liquid output device and the substrate.

[0031] 2. Optimized production process: The liquid output device, axial flow fan and ion fan are coordinated to prepare the conductive film with airflow-assisted directional arrangement. The device design is simple and easy to integrate into the production line.

[0032] 3. Superior Material Compatibility: Suitable for airflow-assisted directional placement of a variety of nanowire materials, such as silver nanowires, carbon nanotubes, and nanofibers. By adjusting the speed of the axial and ion fans, as well as the distance between the liquid output device and the substrate, a variety of linear materials can be directional placed on the substrate, demonstrating broad material compatibility.

[0033] 4. Potential special application value: The prepared single-layer conductive film of directional arrangement wiring material has obvious resistance directionality and a large longitudinal and transverse resistance ratio. It has great potential application value in the fields of directional growth control of crystals and microelectronic control devices.

[0034] 5. Environmentally friendly: Through airflow-assisted production, there is no need to introduce chemical reagents or high-temperature treatment, which reduces pollution to the environment. The device has low energy consumption, further reducing the adverse impact on the environment during the production process.

[0035] 6. Easy to operate and maintain: The equipment used in the process has a simple structure, is easy to operate and maintain. Operators can start operating without complex training, and the equipment has low maintenance costs and a long service life.

[0036] 7. Good repeatability: Compared with other preparation technologies for directional metal nanowire conductive films, the process has good repeatability, ensuring the stability of performance and quality of batch production of directional conductive film products made of linear materials.

[0037] 8. Good substrate compatibility: Directed metal nanowire conductive films can be prepared not only on hard glass, plastic, and metal substrates, but also on various flexible substrates such as PET and PDMS, with good technical compatibility.

[0038] 9. Adjustability of the degree of adhesion between linear materials and substrates: Plasma or ultraviolet light is used to treat the substrate surface to regulate the adhesion of nanowires to the substrate, thereby enabling the preparation of conductive films with good directional effects on the surfaces of substrates of different materials.

[0039] 10. Preparation of directionally arranged conductive films of suitable sizes: By regulating the distance between the axial fan, ion fan, liquid output device and the substrate, large-area directionally arranged metal nanowire conductive films can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a scanning electron microscope image of a conductive film product at 2000 times magnification in the airflow-assisted nanowire material directional arrangement method according to the first embodiment of the present invention;

[0041] Figure 2 This is a statistical analysis of the oriented arrangement of silver nanowires in the airflow-assisted nanowire material oriented arrangement method according to the first embodiment of the present invention;

[0042] Figure 3 This is a scanning electron microscope image of a conductive film product at 7000 times magnification, according to the second embodiment of the present invention, of the airflow-assisted nanowire material directional arrangement method;

[0043] Figure 4 This is a scanning electron microscope image of a conductive film product at 5000 times magnification, showing the airflow-assisted nanowire material directional arrangement method according to the third embodiment of the present invention;

[0044] Figure 5 Schematic diagram of a device for aligning nanowire materials using airflow assistance according to a third embodiment of the present invention;

[0045] Figure 6 This is a scanning electron microscope image of the conductive film product of Comparative Example 1 of the present invention at 2000 times magnification;

[0046] Figure 7 This is a statistical analysis of the oriented arrangement of silver nanowires in Comparative Example 1 of the present invention.

[0047] Reference numerals: 100 - liquid output device, 200 - axial flow fan, 210 - rotating platform, 220 - first wind speed sensor, 230 - second wind speed sensor, 300 - ion fan, 400 - substrate, 500 - base. DETAILED DESCRIPTION

[0048] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0049] Those skilled in the art will appreciate that, unless expressly stated otherwise, the singular forms “a”, “an”, “said”, “above” and “the” used herein may also include plural forms. It should be further understood that the term “comprising” used in the specification of the present invention refers to the presence of the described features, integers, steps, operations, elements, units, modules and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, units, modules, components and / or groups thereof. It should be understood that when we refer to an element as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, “connected” or “coupled” as used herein may include wireless connection or wireless coupling. The term “and / or” used herein includes all or any unit and all combinations of one or more associated listed items.

[0050] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which this invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein. Example 1

[0051] A method for directional arrangement of nanowire materials assisted by airflow is provided, wherein a glass sheet is used as a substrate 400. The linear material in the linear material solution is silver nanowires, and an electric pipette is used as a liquid output device 100. The method specifically includes the following steps:

[0052] 1. Preparation of nanomaterials and cleaning of substrates. Purchase silver nanowires with the following parameters: length of about 20 μm, diameter of about 30 nm, purity > 99 wt%, and a soda-lime glass sheet with an area of ​​10 mm × 10 mm for substrate 400. Cleaning of substrate 400: Place substrate 400 in a beaker, add a small amount of detergent, ultrasonically vibrate for 15 minutes, and then wash with plenty of clean water. Add sufficient deionized water and ultrasonically clean it twice for 15 minutes each time. Pour out the deionized water, add a small amount of dimethyl acetone, and ultrasonically vibrate it twice for 15 minutes each time to remove residual organic matter. Add an appropriate amount of anhydrous ethanol and ultrasonically clean it twice for 20 minutes each time. Add anhydrous ethanol again, and seal the clean substrate 400 that has been washed with anhydrous ethanol for later use.

[0053] 2. Drying and surface modification of substrate 400: The substrate 400 is removed from the anhydrous ethanol seal and dried. The dried substrate 400 is treated with a plasma surface treatment machine at normal pressure for 20 seconds, and then treated with a 185nm ultraviolet ozone lamp for 30 minutes.

[0054] 3. The axial flow fan 200 is located below the output end of the liquid output device 100. The ion fan 300 is arranged vertically spaced apart from the axial flow fan 200. The middle part of the axial flow fan 200 is a rotating platform 210. The processed substrate 400 material is fixed on the rotating platform 210 of the axial flow fan 200. The substrate 400 is installed on the rotating platform 210. The substrate 400 can be fixed on the rotating platform 210 in various ways, such as snap connection, card connection, clamping or magnetic connection. The distance between the electric pipette nozzle and the substrate 400 is 0.2 cm, the rotation speed of the axial flow fan 200 is 2500 rpm, and the wind speed generated by the ion fan 300 is 2.5 m / s.

[0055] The axial fan 200 generates a downward spiral airflow in the space above it, while the ion fan 300 generates an upward airflow in the space above it. A single fan cannot achieve circumferential airflow, especially when the circumferential airflow velocity is high. The resulting negative pressure can also create vertical airflow. The downward spiral wind generated by the axial fan 200, under the action of air viscosity, causes the linear materials to align in the air along the wind speed. The combined arrangement of the axial fan 200 and the ion fan 300 is the core of achieving the directional arrangement of the linear materials. The downward spiral wind generated by the axial fan 200 and the upward wind generated by the ion fan 300 work together to influence the directional external force during the linear material's descent, resulting in an orderly arrangement. The design of this wind field not only requires the coordination of wind speed and direction, but also requires real-time adjustment of the rotational speeds of the axial fan 200 (centrifugal action) and the ion fan 300 based on corresponding speed and wind speed sensors to ensure the ultimate alignment. The ion fan 300 generates an upward wind to reduce the excessive wind speed of the axial fan 200. The distance between the axial fan 200 and the liquid output device 100 is crucial. If the distance is too long, the droplets will easily escape. If the distance is too short, the dispersion effect will be weak and the final product size will be small. Without airflow assistance, spin coating is difficult to achieve the desired effect of producing transparent conductive films with aligned metal nanowires. Without airflow assistance, shear coating can be used to produce transparent conductive films with aligned metal nanowires, but this method suffers from poor orientation, poor reproducibility, and poor controllability. The ion fan 300 generates positive and negative ions through corona discharge. These ions can neutralize the negative charge of the linear material (such as silver nanowires), reducing the electrostatic forces generated within the linear material and between the linear materials. Limiting the distance between the output end of the liquid output device 100 and the substrate 400 ensures that the droplets discharged from the liquid output device 100 are dispersed by the spiral airflow and fall directly onto the substrate 400. The airflow assistance effect can only be achieved within a relatively small distance range.

[0056] 4. Disperse and dilute 5 mg of silver nanowires at a concentration of 5 mg / ml with 99% pure ethanol and 99% pure isopropanol in a volume ratio of 1:0.2:0.8. The concentration of the linear material solution (metal nanowire solution) and the type of dispersion medium are crucial for the final oriented film formation process. Transfer the linear material solution to an electric pipette. The metal nanowire solution drips from the electric pipette, which is then assisted by wind. The droplets are torn and broken apart to form small droplets, which are then oriented. The droplets then fall and disperse onto substrate 400, where they are subjected to strong centrifugal forces, further oriented and oriented, resulting in a wet film. The coating time is 5-20 seconds.

[0057] 5. The prepared wet film is placed in an oven for heat preservation and annealing. The holding temperature is set to 100°C for 15 minutes. The heat treatment method is adjusted according to factors such as the type of linear material and the type of dispersion medium. The tightness of the bonding between the linear material and the substrate 400 can be controlled by treating the substrate 400 surface with plasma or ultraviolet light to adjust the adhesion effect of the linear material to the substrate 400. This allows the preparation of conductive films with well-oriented linear materials on the surfaces of substrates 400 of different materials.

[0058] After testing, the transmittance of the prepared glass substrate 400 silver nanowire conductive film was 92%, the longitudinal square resistance was 30Ω / sq, the resistance showed obvious directionality, and the longitudinal and transverse resistance ratio was greater than 6; its SEM characterization image is shown as follows Figure 1 As shown in Figure 2, silver nanowires have excellent directional arrangement effect. Figure 2 , the degree of single-direction orientation within the range of 50±10° is greater than 63.3%; the square resistance of the prepared substrate 400 silver nanowire conductive film is 40Ω / sq.

[0059] In other implementations, the substrate 400 may also be made of ceramic, etc. The liquid output device 100 may be a precise peristaltic pump, thereby outputting the linear material solution in the form of droplets.

[0060] In other implementations, the silver nanowires have a length of 20 to 40 microns and a diameter of 20 to 100 nanometers. This limits the size of the linear material in the solution. If the linear material's length dimension is too small, the oriented arrangement effect is poor; if it is too large, the performance of the conductive film is poor and the adhesion to the substrate 400 is poor. Similarly, if the linear material's cross-sectional dimension is too small, the oriented arrangement effect is poor; if it is too large, the performance of the conductive film is poor and the adhesion to the substrate 400 is poor.

[0061] In summary, the axial fan 200 generates a downward spiral wind, which, under the action of air viscosity, causes the linear materials to align in the direction of the wind speed. The ion fan 300 generates an upward wind to reduce the excessive downward wind speed generated by the axial fan 200. Once the linear materials are deposited on the surface of the substrate 400, the high-speed rotation generates a sufficiently large centrifugal force, which causes the linear materials to align in a directional manner due to friction and centrifugal forces. Example 2

[0062] On the basis of Example 1, the substrate 400 was replaced with PET; the concentration of the original solution of the silver nanowire linear material was 15 mg / ml, and 5 mg of silver nanowires with a concentration of 15 mg / ml, 99% pure ethanol, and 99% pure isopropanol were taken and dispersed and diluted in a volume ratio of 2:1:2.2; the distance between the electric pipette nozzle and the substrate 400 was 3 cm; the rotation speed of the axial flow fan 200 was 3500 rpm, and the wind speed generated by the ion fan 300 was 4.2 m / s.

[0063] The wet film was prepared by performing the above steps. The prepared wet film was placed in an oven for heat preservation and annealing. The heat preservation temperature was set at 60°C and the heat preservation time was set for 45 minutes.

[0064] After testing, the transmittance of the prepared PET substrate 400 silver nanowire conductive film is 93%, and the square resistance is 60Ω / sq; its SEM characterization is shown in the figure Figure 3 As shown, it has a good directional arrangement effect. Example 3

[0065] Based on Example 1, the difference is that the raw materials are replaced with copper nanowire solution. The parameters of the purchased copper nanowire material are: length of about 20 μm, diameter of about 100 nm, purity>99wt%, 5 mg of copper nanowire with a concentration of 5 mg / ml, 99% pure ethanol, and 99% pure isopropanol are taken, and the copper nanowire material is dispersed and diluted in a volume ratio of 1.5:0.6:1.5.

[0066] After testing, the transmittance of the prepared PET substrate 400 copper nanowire conductive film is 91%, and the square resistance is 80Ω / sq; its SEM characterization is shown in Figure 4 As shown, it has a better directional arrangement effect.

[0067] As demonstrated in Examples 1-3, the preparation of aligned metal nanowire conductive films using the technical solution of the present invention enables precise control of the nanowire arrangement within the nanowire conductive network, resulting in high production efficiency. The aligned metal nanowire conductive films prepared by the present invention exhibit high transmittance, excellent conductivity, and robust alignment; they also exhibit broad compatibility with substrate 400 and nanowire materials.

[0068] Compared with other technical solutions in the prior art, the capillary force method has low preparation efficiency, the water bath thermal convection method has low preparation efficiency and poor uniformity, and the water bath pulling method is only applicable to hydrophilic substrates 400 and silver nanowires and has poor controllability of the operation process.

[0069] Comparative Example 1

[0070] The method for assembling a transparent conductive film of oriented silver nanowires using a high-speed rotating substrate 400 specifically includes the following steps:

[0071] 1. Preparation of nanomaterials and cleaning of substrates. Purchase silver nanowires with the following parameters: length of about 20 μm, diameter of about 30 nm, purity > 99 wt%, and a soda-lime glass sheet with an area of ​​10 mm × 10 mm for substrate 400. Cleaning of substrate 400: Place substrate 400 in a beaker, add a small amount of detergent, ultrasonically vibrate for 15 minutes, and then rinse with plenty of clean water. Add sufficient deionized water and ultrasonically clean it twice for 15 minutes each time. Pour out the deionized water, add a small amount of dimethyl acetone, and ultrasonically vibrate it twice for 15 minutes each time to remove residual organic matter. Add an appropriate amount of anhydrous ethanol and ultrasonically clean it twice for 20 minutes each time. Add anhydrous ethanol again, and seal the clean substrate 400 that has been washed with anhydrous ethanol for later use.

[0072] 2. Drying and surface modification of substrate 400: The substrate 400 is removed from the anhydrous ethanol seal and dried. The dried substrate 400 is treated with a plasma surface treatment machine at normal pressure for 20 seconds, and then treated with a 185nm ultraviolet ozone lamp for 30 minutes.

[0073] 3. Secure the processed substrate 400 to the rotating platform 210 of the axial flow fan 200. Secure the electric pipette, axial flow fan 200, and laser speed measurement device to the base 500. The distance between the electric pipette nozzle and the substrate 400 is 0.5-1.5 cm. The axial flow fan 200 rotates at a speed of 2500-3500 rpm. The blades of the axial flow fan 200 are shielded, specifically with a ring-shaped member, thereby shielding the spiral wind generated by the axial flow fan 200.

[0074] 4. Take 5 mg of silver nanowires with a concentration of 5-15 mg / ml and 99% pure ethanol and 99% pure isopropanol, and disperse and dilute the silver nanowire material in a volume ratio of 1-2:0.2-1:0.8-2.2. Then, the metal nanowire solution dripping from the nozzle of an electric pipette is coated on the surface of a high-speed rotating substrate 400 to prepare a wet film. The coating time is 5-20 seconds.

[0075] 5. Place the prepared wet film in an oven for heat preservation and annealing. The heat preservation temperature is set to 100°C and the heat preservation time is 15 minutes.

[0076] 7. After testing, the transmittance of the prepared substrate 400 silver nanowire transparent conductive film is 91%, the longitudinal square resistance is 22Ω / sq, the resistance shows a certain directionality, and the longitudinal and transverse resistance ratio is 3.60; its SEM characterization is shown in the figure below. Figure 6 As shown. Figure 7The degree of orientation in a single direction within the range of 30±10° is greater than 47.7%.

[0077] Reference Figure 1 、 3 , 4, and 6. In Examples 1, 2, and 3, the degree of directional arrangement is significantly greater than that in Comparative Example 1. In Example 1, the directional arrangement accounts for approximately 63.3% within the 20-degree range, while in Comparative Example 1, the directional arrangement accounts for more than approximately 47.7% within the 20-degree range. This shows that airflow assistance can enhance the effect of directional arrangement. Example 4

[0078] This method is similar to Example 1, except that the axial fan 200 is set to 2500 rpm, then started and the operation of the ion fan 300 is adjusted based on the wind speed (measured) above the axial fan 200. The rotation of the axial fan 200 is fixed, providing a stable centrifugal force on the substrate 400 while generating a downward spiral wind. A wind speed measurement device is installed above the axial fan 200, and the operation of the ion fan 300 is adjusted based on the wind speed above the axial fan 200, so that the vertical airflow velocity in the area above the axial fan 200 is as low as possible. Example 5

[0079] A method for aligning nanowire materials with airflow assistance involves computer simulation prior to production. The method specifically includes the following steps:

[0080] S1.1. By constructing a physical model, with the optimization objectives of increasing the circumferential airflow velocity of the axial flow fan 200 and reducing the vertical airflow velocity above the axial flow fan 200, the operating parameters of the axial flow fan 200 and the ion fan 300 were simulated and calculated. The operating parameters included the rotational speed of the axial flow fan 200, the wind speed of the ion fan 300, and the distance between the axial flow fan 200 and the ion fan 300. The boundary conditions were: the vertical distance between the output end of the liquid output device and the substrate was 0.2-3 cm; the rotational speed of the axial flow fan was 2500-3500 rpm; and the wind speed generated by the ion fan was 2.5-4.2 m / s.

[0081] S1. According to the simulation results, a liquid output device, an axial flow fan and an ion fan are set, wherein the axial flow fan is located below the output end of the liquid output device, the ion fan is located below the axial flow fan, the middle part of the axial flow fan is a rotating platform, the axial flow fan generates a downward spiral airflow, and the ion fan generates an upward airflow.

[0082] S2. Prepare a linear material solution and transfer it to the liquid output device, wherein the liquid output device is used to output the linear material solution in the form of droplets.

[0083] S3. Install the substrate on the rotating platform.

[0084] S4. Start the liquid output device, the axial flow fan and the ion fan to form a wet film on the surface of the high-speed rotating substrate.

[0085] S5. Stop the operation of the liquid output device, the axial flow fan and the ion fan, remove the substrate and perform heat treatment to form a conductive film.

[0086] In this embodiment, computer simulation is used to provide guidance on adjusting the working states of the axial flow fan 200 and the ion fan 300. After constructing the physical models of the axial flow fan 200 and the ion fan 300 and setting the boundary conditions, the state of the airflow during the operation of the constructed physical model can be calculated. In addition, after the droplet boundary conditions are introduced, the simulation process can not only simulate the airflow field, but also simulate the working effect of the droplets in the airflow field, thereby providing guidance for the entire process engineering. The optimization parameters are set to the circumferential airflow velocity in the area above the axial flow fan 200 being as large as possible, and the vertical airflow velocity in the area above the axial flow fan 200 being as small as possible. Finally, guidance on the working states of the axial flow fan 200 and the ion fan 300 can be obtained, such as the setting position and speed of the axial flow fan 200 and the ion fan 300. Various types of optimization algorithms can be used to calculate the working parameters, which are not limited here.

[0087] In other implementations, the middle part of the axial fan 200 is a fan assembly, which includes a central axis and a fan blade portion arranged circumferentially around the central axis. The optimization target also includes the proportion of droplets falling onto the substrate 400, and the operating parameters of the axial fan 200 include the size of the central axis and the fan blade portion. Considering that the substrate 400 is arranged on the central axis of the axial fan 200, the proportion of droplets entering the fan blade portion should be as low as possible, thus forming a set of contradictions, namely, to generate a wind field with a larger size and a larger pressure difference as much as possible, but to avoid droplets entering the fan blade portion as much as possible. In other implementations, new optimization targets (such as the uniformity of linear material distribution) and new optimization variables (such as the wind field intensity change process) can be added to further optimize the entire process. Example 6

[0088] Reference Figure 5 The present invention also provides a device for use in the above-mentioned airflow-assisted nano-linear material directional arrangement method, comprising a base 500, a liquid output device 100, an axial flow fan 200 and an ion fan 300.

[0089] The base 500 serves as the structural foundation.

[0090] The liquid output device 100 is disposed at the upper portion of the base 500 in the height direction;

[0091] An axial flow fan 200 is disposed below the output end of the liquid output device 100. A rotating platform 210 is disposed in the middle of the axial flow fan 200. An external substrate 400 is mounted on the upper portion of the rotating platform 210. A first wind speed sensor 220 for measuring circumferential wind speed is disposed on the outer periphery of the space above the axial flow fan 200. A second wind speed sensor 230 for measuring vertical wind speed is disposed on the outer periphery of the space above the axial flow fan 200.

[0092] The ion fan 300 is vertically spaced apart from the axial flow fan 200 , wherein the axial flow fan 200 generates a downward spiral airflow in the space above the axial flow fan 200 , and the ion fan 300 generates an upward airflow in the space above the axial flow fan 200 .

[0093] In this embodiment, the specific method of using the device is similar to that of the aforementioned method embodiment and will not be further described here. The first wind speed sensor 220 and the second wind speed sensor 230 respectively measure wind speed in the circumferential and vertical directions, thereby providing guidance for the operation of the entire device to ensure optimal process conditions. The operating method of the first wind speed sensor 220 and the second wind speed sensor 230 is not limited and can be a Pitot tube, etc., as long as they can achieve wind speed measurement.

[0094] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for directional arrangement of nanowire materials assisted by airflow, characterized in that: include: S1. Setting a liquid output device, an axial flow fan, and an ion fan, wherein the axial flow fan is located below the output end of the liquid output device, the ion fan is located below the axial flow fan, the middle portion of the axial flow fan is a rotating platform, the axial flow fan generates a downward spiral airflow, and the ion fan generates an upward airflow; S2. preparing a linear material solution and transferring it to the liquid output device, wherein the liquid output device is used to output the linear material solution in the form of droplets; S3, mounting a substrate on the rotating platform, with the output end of the liquid output device and the substrate spaced vertically at a distance of 0.2-3 cm; S4. Starting the liquid output device, the axial flow fan, and the ion fan to form a wet film on the surface of the substrate rotating at high speed, wherein the rotation speed of the axial flow fan is 2500-3500 rpm, and the wind speed generated by the ion fan is 2.5-4.2 m / s; S5. Stop the operation of the liquid output device, the axial flow fan, and the ion fan, remove the substrate, and perform heat treatment to form a conductive film.

2. The airflow-assisted nanowire material directional arrangement method according to claim 1, characterized in that: The step of S1 includes: S1.1 constructs a physical model, takes increasing the circumferential airflow velocity of the axial flow fan and decreasing the vertical airflow velocity above the axial flow fan as optimization goals, and simulates and calculates the operating parameters of the axial flow fan and the ion fan.

3. The airflow-assisted nanowire material directional arrangement method according to claim 2, characterized in that: The middle part of the axial flow fan is a fan assembly, which includes a central axis and a fan blade portion arranged circumferentially of the central axis. In the step S1.1: the optimization target also includes the proportion of droplets falling onto the substrate, and the operating parameters of the axial flow fan include the dimensions of the central axis and the fan blade portion.

4. The airflow-assisted nanowire material directional arrangement method according to any one of claims 1 to 3, characterized in that: The steps of S4 include: Starting and adjusting the axial flow fan to a set speed; Starting and adjusting the operation of the ion fan according to the wind speed above the axial flow fan; The liquid output device is started to apply liquid on the surface of the substrate rotating at a high speed to form a wet film.

5. The airflow-assisted nanowire material directional arrangement method according to any one of claims 1 to 3, characterized in that: In the step S3, the material of the substrate is one of inorganic non-metal, metal and polymer.

6. The airflow-assisted nanowire material directional arrangement method according to any one of claims 1 to 3, characterized in that: The length of the linear material in the linear material solution is 20 to 40 microns, and the diameter is 20 to 100 nanometers.

7. The airflow-assisted nanowire material directional arrangement method according to any one of claims 1 to 3, characterized in that: The liquid output device is an electric pipette or a peristaltic pump.

8. The airflow-assisted nanowire material directional arrangement method according to any one of claims 1 to 3, characterized in that: In the step S2, the linear material solution is prepared by mixing a linear material solution stock solution with a concentration of 5-15 mg / ml, ethanol and isopropanol in a volume ratio of 1-2:0.2-1:0.8-2.

2.

9. A device for use in the airflow-assisted nanowire material directional arrangement method according to any one of claims 1 to 8, characterized in that: include: base; a liquid output device, arranged at the upper portion of the base in the height direction; an axial flow fan, correspondingly disposed below the output end of the liquid output device, wherein the middle portion of the axial flow fan is a rotating platform, wherein the upper portion of the rotating platform is used to mount an external substrate; The ion fan is vertically spaced apart from the axial flow fan, wherein the axial flow fan generates a downward spiral airflow in the space above the axial flow fan, and the ion fan generates an upward airflow in the space above the axial flow fan.

10. The device according to claim 9, characterized in that A first wind speed sensor for measuring circumferential wind speed is provided at the periphery of the space above the axial flow fan, and a second wind speed sensor for measuring vertical wind speed is provided at the space above the axial flow fan.

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