CN111710473A - A kind of preparation method of patterned flexible conductive film - Google Patents

Abstract

The invention belongs to the field of flexible electronic devices, and discloses a preparation method of a patterned flexible conductive film, comprising: (1) preparing a nanowire conductive film layer and a water-soluble polymer film layer on a flexible substrate in sequence; (2) by The electrohydrodynamic near-field direct writing process uses a polymer solution to directly write micro-nano-scale patterns on the surface of the water-soluble polymer film layer, and etch the pattern structure; (3) use the above patterned polymer film as a mask layer The nanowire conductive film layer is chemically treated, and the unmasked nanowire conductive film is removed; (4) the residual water-soluble polymer film is removed with deionized water, and dried to obtain a flexible transparent conductive film. The invention is based on the combination of the electro-fluid near-field direct writing process and the template method, and uses the polymer fibers obtained by the direct writing process as the template or template etchant for preparing the nanowire film, thereby realizing the preparation of the patterned flexible conductive film.

Description

A kind of preparation method of patterned flexible conductive film

technical field

The invention belongs to the field of flexible electronic devices, in particular to a preparation method of a patterned flexible conductive film.

Background technique

Transparent conductive film is a kind of functional film with high conductivity and excellent optical transmittance in the visible light wavelength range. It is mainly used as a transparent electrode. It is the most critical and basic component of various electronic devices. It is indispensable in optoelectronic devices such as batteries, LCDs, and OLEDs. However, the choice of materials that combine high optical transparency and good electrical conductivity is limited, as high carrier concentrations usually imply strong light absorption. Indium tin oxide (ITO) has both properties and is therefore widely used. However, the use of ITO as a transparent electrode has many disadvantages: (1) the indium storage and utilization are low; (2) the material needs to be deposited at high temperature; (3) it is relatively hard and brittle, and lacks ductility.

With the rapid development of the optoelectronic industry, the application fields of transparent conductive films have been continuously expanded, and higher requirements have been placed on their physical and chemical properties. The emergence of flexible devices such as wearable devices, flexible displays, and electronic skins poses new challenges to electrodes , the traditional electrode ITO is more and more difficult to meet the requirements. Therefore, many materials have been sought to replace ITO for future flexible optoelectronic devices. Among the materials that are more likely to be substituted include carbon-based materials such as carbon nanotubes (CNT), graphene, polymeric materials such as PEDOT:PSS, metal nanoparticles (NPS), and metal nanowires (NWS).

In recent years, flexible electrodes represented by wire electrodes have become an important research direction. Nanowires can be classified into different types, including metallic nanowires, semiconductor nanowires, and insulator nanowires. But in the field of electrode materials/conductive thin films, our more commonly used materials are nanotubes, graphene, and metal nanowires. They can all use solution coating technology to achieve large-scale large-scale production. If these new materials are to be used in optoelectronic devices on a large scale, we must achieve improvements in their optoelectronic properties. Patterning nanowire electrodes is a very effective method among many improvement approaches. Therefore, it is of great practical significance to actively study the optoelectronic performance parameters of nanowire networks and the process of patterning nanowires for accelerating the development of flexible optoelectronics industry.

Silver nanowire transparent conductive film with unique and innovative nano-silver wire technology has more excellent durability, high flexibility and low resistance than traditional ITO, and its benefits can reach several times that of ITO. At the same time, the silver nanowire transparent conductive film has good compatibility and can be applied to the existing industrial process; the stability of the material can also shorten the time required for the process, in addition, it has superior environmental reliability and related characteristics, Meets the optical and electrical properties required by the current industry. The application range of the industry is also very wide, including touch panels, displays, flexible displays, and solar energy and other related fields, and it is an ideal ITO replacement material. According to the study, a grid of finely spaced metal structures can provide high transparency at low sheet resistance, which can severely affect the optical and electrical properties of the grid. Therefore, it becomes a possible option to achieve better performance by fabricating micropatterned structures on the surface of silver nanowire films. However, the current patterning process of silver nanowires requires specific instruments (lithography machine, PDMS mask, etc.), and only limited materials can be used. Preparation of patterned silver nanowire thin films.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the deficiencies of the above-mentioned technologies, and to provide a method for preparing a patterned flexible conductive film. By adjusting the concentration of the polymer solution, the rapid green preparation of high-resolution large-area nanowire electrodes with sub-micron feature size, neat edges, and complex patterns is realized. This technical solution is easy to implement, pollution-free, widely used in materials, and can realize rapid preparation in a large area.

In order to achieve the above-mentioned purpose, the present invention provides a preparation method of a flexible transparent conductive film, which comprises the following steps:

(1) preparing a nanowire conductive film layer and a water-soluble polymer film layer on a flexible substrate in turn;

(2) Prepare a high molecular polymer solution with a certain concentration, add it to a syringe pump for use, and use the high molecular polymer solution to directly write a micro-nano scale pattern on the surface of the water-soluble polymer film layer through an electrohydrodynamic near-field direct writing process. etching out the pattern structure to obtain a patterned polymer film;

(3) chemically treating the nanowire conductive film layer with the above-mentioned patterned polymer film as a mask layer, and removing the unmasked nanowire conductive film;

(4) using deionized water to remove the remaining water-soluble polymer film, and drying to obtain a flexible transparent conductive film.

Further, in the step (1), the flexible substrate includes a flexible glass and a flexible polymer substrate, and the flexible substrate is made of polycarbonate, polyimide, polydimethylsiloxane, polytetrafluoroethylene Single-layer or multi-layer substrates prepared from one or more of ethylene phthalate.

Further, in the step (1), a solution film-making method is used to prepare the nanowire conductive film layer and the water-soluble polymer film layer, and the solution film-making method is spin coating, bar coating, screen printing, spray coating , one of blade coating, dip coating, slit coating and embossing.

Further, in the step (1), the thickness of the nanowire conductive film layer is 0.1-100 microns, and the thickness of the polymer film layer is 0.1-100 microns.

Further, in the step (1), the preparation of the water-soluble polymer thin film layer is cancelled, and only the nanowire conductive thin film layer is prepared on the flexible substrate, that is, the template is changed.

Further, the high molecular polymer in the step (2) includes polyvinyl alcohol, polyoxyethylene and ethylene-vinyl alcohol copolymer.

Further, the concentration of the polymer solution configured in the step (2) should be changed with the method. When the nanowire conductive film layer and the water-soluble polymer film layer are sequentially prepared on the flexible substrate in the step (1), in order to make Template, at this time, the direct writing solution needs to contain more water to erode the water-soluble polymer layer, and the concentration of the high molecular polymer solution is 0.5-1%.

When there is no polymer layer in step (1), the concentration of the direct-writing polymer solution should be high, so that the direct-writing spinning is used as a template for subsequent operations, and in step (1), it is only prepared on a flexible substrate When the nanowire conductive thin film layer is used, the concentration of the high molecular polymer solution is 3-4%.

Further, the electrohydrodynamic near-field direct writing process adopted in step (2) is also called near-field direct writing solution electrospinning technology. An electrostatic electric field is formed between the collecting substrates. Under the action of the electric field force, the mobile charges accumulate on the surface of the liquid, and the Coulomb force of the charges causes shear stress on the liquid surface. Under the action of the shear force, the solution forms a Taylor cone at the nozzle. When the electric field strength increases, the force of the electric field overcomes the surface tension of the liquid, and a jet is generated at the top of the Taylor cone. This jetting mode is called the cone jet mode. The diameter of the jetted droplet is usually 0.01 to 0.2 times the diameter of the nozzle, so as to achieve high-resolution printing.

Further, in step (2), when implementing electrohydrodynamic near-field direct writing, the distance between the nozzle of the device and the flexible substrate is 0.3 mm to 0.5 mm, and the inner diameter of the needle tube used by the nozzle is related to the type of needle used. The flow rate during injection is 30 μL/min to 250 μL/min, the flexible substrate is heated, the heating temperature is 10°C to 50°C, and the applied voltage is 5 kV to 15 kV.

Further, when the nanowire conductive thin film layer in the step (3) is made of metal nanowire materials, the metal nanowires are not masked to generate metal oxides in the area, and then the substrate is wet-etched by using an acid-based etching solution , the metal oxide chemically reacts and dissolves, and the nanowire conductive film that is not masked by the protective layer is etched and removed.

Further, when the nanowire conductive thin film layer in the step (3) is made of carbon nanotubes, the carbon nanotubes are removed by oxygen plasma etching.

Further, in the step (3), the acid-based etching solution is acetic acid, dilute nitric acid, sulfuric acid, hydrochloric acid or any acid that reacts with metal oxides.

Compared with the prior art, the beneficial effects of the present invention are as follows:

Compared with the prior art, the beneficial effects of the method for preparing the patterned flexible conductive film provided by the present invention are:

The invention provides a preparation method of a patterned flexible conductive film. Based on the combination of an electrofluidic near-field direct writing (electrospinning) process and a template method, the polymer filaments (spinning) obtained by the direct writing process are used as the preparation of nanowires. The template of the film or the template etchant, so as to realize the preparation of the patterned flexible conductive film. And different positioning of the polymer spinning is adopted to realize the complementary or the same pattern between the template pattern and the nanowire film pattern.

The invention utilizes the large-area electrohydrodynamic near-field direct writing to print the high molecular polymer, and realizes the "one positive and one negative" complementary patterned preparation of the nanowire conductive film by adjusting the concentration of the polymer solution, and can realize sub- Rapid green fabrication of high-resolution large-area nanowire electrodes with micron-scale feature sizes, neat edges, and complex patterns. This technical solution is easy to implement, pollution-free, widely used in materials, and can realize rapid preparation in a large area.

Description of drawings

Fig. 1 is the overall structure schematic diagram after the direct writing pattern is completed;

2 is a schematic diagram of a patterned water-soluble polymer layer structure;

FIG. 3 is a schematic diagram of the structure of the nanowire layer after the polymer layer template is etched;

4 is a schematic structural diagram of a final patterned nanowire layer with a water-soluble polymer film layer;

5 is a schematic structural diagram when only the nanowire conductive thin film layer is prepared on the flexible substrate;

Fig. 6 is the principle schematic diagram of electrohydrodynamic near-field direct writing process;

7 is a schematic structural diagram of a final patterned nanowire layer of a water-free polymer film layer;

8 is a scanning electron microscope image of the patterned nanowire layer prepared in Example 1, wherein (a) the SEM image of the silver nanowire network obtained by blade coating, and (b) the electrospinning on the silver nanowire network SEM image of silk PEO, (c) is the SEM image of the silver nanowire network with masking layer treated with plasma oxygen, (d) is the SEM image of the patterned silver nanowire network after cleaning and drying, (e) is the SEM image of the patterned silver nanowire network. (b) The partially enlarged SEM image in the figure, (f) is the partially enlarged SEM image in (c), and (g) is the partially enlarged SEM image in (d).

Detailed ways

Referring to Figures 1-8, the present invention provides a method for preparing a patterned flexible conductive film, the method comprising the following steps:

(1) preparing a nanowire conductive film layer and a water-soluble polymer film layer on a flexible substrate in turn;

(2) Prepare a high molecular polymer solution with a certain concentration, add a syringe pump for use, and directly write a micro-nano scale pattern on the surface of the water-soluble polymer film through the electro-fluid direct writing process, as shown in Figure 1, which is a direct writing A schematic diagram of the overall structure after the pattern is completed, the pattern structure is etched to obtain a patterned polymer film, as shown in Figure 2;

(3) chemically treating the nanowire conductive film layer with the above-mentioned patterned polymer film as a mask layer, and removing the unmasked nanowire conductive film, as shown in Figure 3;

(4) Deionized water is used to remove the remaining water-soluble polymer film, and then dried to obtain a flexible transparent conductive film, as shown in FIG. 4 , which is the final patterned nanowire layer.

Further, in the step (1), the flexible substrate includes a flexible glass and a flexible polymer substrate, and the flexible substrate is made of polycarbonate, polyimide, polydimethylsiloxane, polytetrafluoroethylene Single-layer or multi-layer substrates prepared from one or more of ethylene phthalate.

Further, in the step (1), a solution film-making method is used to prepare the nanowire conductive film layer and the water-soluble polymer film layer, and the solution film-making method is spin coating, bar coating, screen printing, spray coating , one of blade coating, dip coating, slit coating and embossing.

Further, in the step (1), the nanowire conductive film layer is made of metal nanowire material or carbon nanotube material, the nanowire conductive film layer has a thickness of 0.1-100 microns, and the water-soluble polymer film layer is made of silk protein solution. Or bead silk protein solution preparation, the thickness of the water-soluble polymer film layer is 0.1-100 microns.

Further, in the step (1), the preparation of the water-soluble polymer thin film layer is cancelled, and only the nanowire conductive thin film layer is prepared on the flexible substrate, that is, the template is changed.

Further, the high molecular polymer in the step (2) includes polyvinyl alcohol, polyoxyethylene and ethylene-vinyl alcohol copolymer.

Further, the concentration of the polymer solution configured in the step (2) should be changed with the method. When the nanowire conductive film layer and the water-soluble polymer film layer are sequentially prepared on the flexible substrate in the step (1), in order to make Template, at this time, the direct writing solution needs to contain more water to erode the water-soluble polymer layer, and the concentration of the high molecular polymer solution is 0.5-1%.

When there is no polymer layer in step (1), the concentration of the direct-writing polymer solution should be high, so that the direct-writing spinning is used as a template for subsequent operations, and in step (1), it is only prepared on a flexible substrate When the nanowire conductive thin film layer is used, the concentration of the polymer solution is 3-4%, as shown in FIG. 5 .

Further, the electrohydrodynamic near-field direct writing process adopted in step (2), also known as near-field direct writing solution electrospinning technology, as shown in Figure 6, the principle is to apply a high voltage on the nozzle to collect the plate Connect the electricity to form an electrostatic electric field between the nozzle and the collecting substrate. Under the action of the electric field force, the mobile charges gather on the surface of the liquid, and the Coulomb force of the charge causes shear stress on the surface of the liquid. Under the action of the shear force, the solution is at the nozzle. A Taylor cone is formed. With the increase of the electric field strength, the force of the electric field overcomes the surface tension of the liquid, and a jet is generated at the top of the Taylor cone. This jet mode is called the cone jet mode. High-resolution printing.

Further, in step (2), when implementing electrohydrodynamic near-field direct writing, the distance between the nozzle of the device and the flexible substrate is 0.3 mm to 0.5 mm, and the inner diameter of the needle tube used by the nozzle is related to the type of needle used. The flow rate during injection is 30 μL/min to 250 μL/min, the flexible substrate is heated, the heating temperature is 10°C to 50°C, and the applied voltage is 5 kV to 15 kV.

Further, in the step (3), the nanowire conductive thin film layer is made of metal nanowire materials, and the metal nanowires are not masked to generate metal oxides in the area, and then the substrate is wet-etched with an acid-based etching solution, The metal oxide reacts chemically and dissolves, and the conductive nanowire film that is not masked by the protective layer is removed by etching.

Further, in the step (3), the nanowire conductive thin film layer is made of carbon nanotubes, and the carbon nanotubes are removed by oxygen plasma etching.

Further, in the step (3), the acid-based etching solution is acetic acid, dilute nitric acid, sulfuric acid, hydrochloric acid or any acid that reacts with metal oxides.

It should be noted that, in step (1), in the case of a water-soluble polymer, the structure of the finally obtained nanowire film is shown in Figure 4. It can be seen from the figure that the final nanowire film pattern is polymerized with the written polymer The object patterns are just complementary structures.

In step (1), in the absence of water-soluble polymer, the structure of the finally obtained nanowire film is shown in Figure 7, and it can be seen from the figure that the final nanowire film pattern is consistent with the written polymer pattern.

Specifically, in step (4), deionized water is used for rinsing and drying to obtain a patterned nanowire film.

The present invention will be described in detail below through specific implementation examples. The scope of the present invention is not limited to this specific embodiment.

Example 1

(1) In this embodiment, the material of the flexible substrate is polycarbonate (PC), select and clean the PC flexible substrate, use acetone, ethanol and deionized ultrasonic cleaning in sequence for 10 minutes during cleaning, and then bake it with an infrared lamp;

(2) A silver nanowire conductive thin film layer is prepared on a flexible substrate by means of doctor blade coating. During the blade coating process, the distance between the blade and the flexible substrate was 800 microns, the coating speed was 15 mm/min, and the nanowire solution was dispersed in deionized water with a concentration of 10 mg/ml. The diameter is about 30 nanometers and the length is about 30 micrometers. After the blade coating is completed, place the sample on a heating table at 100°C to heat and sinter the silver nanowires for half an hour, and then place it at room temperature to drop to room temperature;

(4) using deionized water and PEO to prepare a solution with a mass concentration of 4%, adding a syringe for use;

(5) Input the desired pattern shape and adjust the parameters of the electrofluidic direct writing device (self-made), so that the distance between the nozzle and the flexible substrate is 0.5 mm, the flexible substrate is heated to 40°C, and the voltage is 9kV. After the adjustment is completed, the electrofluidic direct write operation is performed. Among them, the inner diameter of the needle is 200 μm, and the solution supply speed is 200 μl/min;

(6) The sample was taken out and placed in a plasma etching machine for oxygen plasma treatment for 300s. The exposed silver nanowire area without PEO shape protection was oxidized on the surface under the action of plasma oxygen to become non-conductive silver oxide, while The overlapping part is preserved due to masking protection;

(7) the sample that the oxidation treatment is completed is put into the acetic acid solution with a concentration of 80%, and soaked for ten minutes;

(8) Rinse the surface of the sample with deionized water to remove residual acetic acid, rinse for 3 to 5 minutes, and then dry to obtain a patterned silver nanowire conductive film.

Example 2

(1) In this embodiment, the material of the flexible substrate is polyethylene terephthalate (PET), and the flexible PET substrate is selected and cleaned. During cleaning, ethanol and deionization are used for ultrasonic cleaning for 10 minutes each, and then infrared rays are used for cleaning. light drying

(2) The carbon nanotube flexible transparent conductive film layer is prepared by wet method. First, choose single-walled carbon nanotubes with a purity of 95% and anionic surfactant sodium dodecylbenzenesulfonate (SDBS) to prepare a carbon nanotube dispersion in a ratio of 1:10, and then place them in a water bath at 60 °C Heating for 10 minutes, then take by weighing the nonionic surfactant Triton X.100 (TX100) with a mass ratio of 1:2 to the surfactant SDBS, slowly add it to the carbon nanotube dispersion, and continue to stir at a low speed After 15 minutes, the solution was taken out and placed in an ultrasonic machine to be sonicated for several minutes to obtain a carbon nanotube ink with good dispersion properties that can be coated.

(3) The carbon nanotube film is prepared by the rod coating method, and a wire-wound rod with a characteristic length of 1 mm and a coil diameter of 0.3 mm is taken to prepare the film, and the thickness of the corresponding coating liquid film is about 27 microns. Place the polyimide (PI) film on the coating plate, draw an appropriate amount of the coating liquid with a dropper and place it on the PET, then use an RDS coating rod to scrape it from top to bottom, and finally dry it at room temperature.

(4) After the film is dried, soak in deionized water for 40 minutes to initially remove water-soluble SDBS and TX100, then place the film in a vacuum drying oven at 80°C for 30 minutes, take out the film and put it in deionized water for cleaning, and the drying is completed. .

(5) The water-soluble polymer film layer is prepared with silk protein solution. After the step (4) is completed, drop the fibroin solution on the upper surface of the sample, spin-coat on the spin coater to prepare the fibroin layer, set the rotational speed to 600 rpm, and the spin coating time to 40 seconds. Air dry naturally;

(6) using deionized water and PEO to prepare a solution with a mass concentration of 1%, adding a syringe for use;

(7) Adjust the parameters of the electrofluidic direct writing device (self-made), set the voltage to 13.5kV, and perform the electro-atomization operation after the parameter adjustment is completed. The inner diameter of the needle is 200 μm, and the solution supply speed is 200 μl/min.

(8) Remove the sample and put it into a plasma etching machine for oxygen plasma treatment for 300s. The exposed carbon nanotubes without the protection of the silk protein layer are etched and removed, and the overlapping carbon nanotubes are still protected by masking. Good electrical conductivity.

(9) Rinse the surface of the sample with deionized water and dry to obtain a patterned carbon nanotube flexible transparent conductive film.

Example 3

(1) In this embodiment, the material of the flexible substrate is polyimide (PI), and the PI flexible substrate is selected and cleaned. During cleaning, acetone, ethanol and deionization are successively used for ultrasonic cleaning for 10 minutes, and then baked with an infrared lamp. ;

(2) A silver nanowire conductive thin film layer is prepared on a flexible substrate by means of doctor blade coating. During the blade coating process, the distance between the blade and the flexible substrate was 800 microns, the coating speed was 15 mm/min, and the nanowire solution was dispersed in deionized water with a concentration of 10 mg/ml. The diameter is about 30 nanometers and the length is about 30 micrometers. After the blade coating is completed, place the sample on a heating table at 100°C to heat and sinter the silver nanowires for half an hour, and then place it at room temperature to drop to room temperature;

(3) The water-soluble polymer film layer is prepared by using bead silk protein solution. After the step (4) is completed, drop the bead silk protein solution on the upper surface of the sample, spin-coat the bead silk protein layer on the spin coater, set the rotation speed to 800 rpm, and the spin coating time to 35 seconds. Let it dry naturally;

(4) using deionized water and PEO to prepare a solution with a mass concentration of 1%, adding a syringe for use;

(5) Adjust the parameters of the electrofluidic direct writing device (self-made), set the voltage to 13.5kV, and perform the electro-atomization operation after the parameter adjustment is completed. The inner diameter of the needle is 200 μm, and the solution supply speed is 200 μl/min.

(6) Take the sample out and put it into the plasma etching machine for oxygen plasma treatment for 300s. The exposed silver nanowires protected by the non-bead silk protein layer are etched and removed, and the overlapping part of the silver nanowires is still protected by masking. Has good electrical conductivity.

(7) Rinse the surface of the sample with deionized water and dry to obtain a patterned silver nanowire flexible transparent conductive film.

Taking Example 4 as an example, we carried out a SEM scanning test on the patterned nanowire layer prepared in Example 1. Figure 8 is a scanning electron microscope image of the patterned nanowire layer prepared in Example 1. From Figure 8(b) ) and Fig. 8(e), we can observe that the pattern shape obtained by direct writing of higher concentration of PEO is relatively regular, and from Fig. 8(c) and Fig. 8(f), it can be observed that after plasma oxygen treatment, it is not masked The silver nanowire area of is broken, indicating that this area has been oxidized. Finally, it can be observed from Figure 8(d) and Figure 8(g) that after acid treatment and deionized water rinsing and drying, silver nanowire films consistent with the direct-writing pattern were obtained.

It should be noted that the present invention is essentially a comprehensive application of electrohydrodynamic near-field direct writing process, template method and material properties.

(1) In the basic method, a patterned water-soluble polymer is used as a template to realize the patterning operation of silver nanowires.

(2) The high-molecular polymer solution of electrofluid direct writing can be used as an etchant or a template, and the dividing line between the two cases lies in the concentration of the direct writing solution.

(3) A pattern of a certain shape can be directly written by using a polymer solution with a higher concentration. Due to its higher concentration, the water in the solution is less, so by applying temperature to the substrate, the shape of the polymer pattern is kept stable, and then acts as a template.

(4) When a lower concentration polymer solution (taking PEO as an example) is used to directly write the pattern, because the distance between the receiving platform and the nozzle is short and the concentration of PEO in the solution is low, the PEO solution cannot reach the nozzle. The volatile water falls on the water-soluble polymer film layer, and the water that does not volatilize in time will dissolve the water-soluble polymer film covered on the reconstructed nanowire film, and the original nanowire film will show the PEO spinning pattern of near-field direct writing. At this time, we can also realize the preparation of patterned nanowire films by using water-soluble polymers as templates.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (10)

1. A method for preparing a patterned flexible conductive film, comprising the steps of:

(1) sequentially preparing a nanowire conductive thin film layer and a water-soluble polymer thin film layer on a flexible substrate;

(2) directly writing a micro-nano scale pattern on the surface of the water-soluble polymer film layer by using a high molecular polymer solution through an electrohydrodynamic near-field direct writing process, and etching a pattern structure to obtain a patterned polymer film;

(3) chemically treating the nanowire conductive thin film layer by taking the patterned polymer thin film as a mask layer, and removing the unmasked nanowire conductive thin film;

(4) and removing the residual water-soluble polymer film by using deionized water, and drying to obtain the flexible transparent conductive film.

2. The method of claim 1, wherein the flexible substrate in step (1) comprises a flexible glass and a flexible polymer substrate, and the flexible substrate is a single-layer or multi-layer substrate made of one or more of polycarbonate, polyimide, polydimethylsiloxane and polyethylene terephthalate.

3. The method of claim 1, wherein the nanowire conductive thin film layer and the water-soluble polymer thin film layer are prepared in step (1) by a solution film-forming method, wherein the solution film-forming method is one of spin coating, bar coating, screen printing, spray coating, blade coating, dip coating, slit coating, and stamping.

4. The method for preparing the patterned flexible conductive film according to claim 1, wherein in the step (1), the nanowire conductive film layer is made of a metal nanowire material or a carbon nanotube material, the thickness of the nanowire conductive film layer is 0.1-100 micrometers, the water-soluble polymer film layer is prepared from a fibroin solution or a globin solution, and the thickness of the water-soluble polymer film layer is 0.1-100 micrometers.

5. The method for preparing a patterned flexible conductive film according to claim 1, wherein the step (1) is performed without preparing the water-soluble polymer thin film layer, and only the nanowire conductive thin film layer is prepared on the flexible substrate, i.e. the template is changed.

6. The method of claim 1, wherein the polymer in step (2) comprises one of polyvinyl alcohol, polyoxyethylene, or ethylene-vinyl alcohol copolymer.

7. The method for preparing the patterned flexible conductive film according to claims 5 and 6, wherein when the nanowire conductive film layer and the water-soluble polymer film layer are prepared on the flexible substrate in sequence in the step (1), the mass concentration of the high molecular polymer solution is 0.5-1%;

when the nanowire conductive thin film layer is prepared on the flexible substrate in the step (1), the mass concentration of the high molecular polymer solution is 3-4%.

8. The method for preparing the patterned flexible conductive film according to claim 4, wherein when the nanowire conductive thin film layer in the step (3) is made of the metal nanowire material, the unmasked region of the metal nanowire generates metal oxide, and then the substrate is subjected to wet etching by using acid etching liquid, so that the metal oxide is chemically reacted and dissolved, and the nanowire conductive thin film which is not masked by the protective layer is etched and removed.

9. The method for preparing the patterned flexible conductive film according to claim 4, wherein when the nanowire conductive thin film layer in the step (3) is made of the carbon nanotube material, the carbon nanotube is etched and removed by oxygen plasma.

10. The method for preparing the patterned flexible conductive film according to claim 8, wherein the acid etching solution in the step (3) is acetic acid, dilute nitric acid, sulfuric acid, hydrochloric acid or any acid that reacts with metal oxide.

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