A flexible transparent conductive polymer film suitable for a curved display screen and a preparation process thereof

Abstract

The application belongs to the technical field of conductive film preparation, and particularly relates to a flexible transparent conductive polymer film suitable for a curved display screen and a preparation process thereof, which comprises the following steps: S1, preparing a silver ammonia solution containing silver nanowires; S2, forming a film of the silver ammonia solution containing silver nanowires on a hydrophilic flexible polymer substrate; and S3, performing reduction treatment on the film obtained in step S2 to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film. The silver ammonia solution containing silver nanowires is compounded, and a hydrophilic flexible polymer substrate is combined, silver nanoparticles generated in situ are doped in the silver nanowires, and the silver nanoparticles simultaneously play a role in connecting the silver nanowires and the substrate, so that the conductivity and adhesion of the conductive layer are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of conductive film preparation, and particularly relates to a flexible transparent conductive polymer film suitable for a curved display screen and a preparation process thereof. BACKGROUND

[0002] Flexible electronic devices have become crucial in the development of effective and stretchable optoelectronic devices (such as organic light-emitting diodes, touch screens, e-readers, electronic paper and organic photovoltaic devices), and a basic component of the flexible electronic devices is a transparent conductive film, which is a thin film material with high light transmittance and excellent conductivity in the visible light range. The curved screen is an optical device with a certain curvature, and therefore needs to have good flexibility. Indium tin oxide conductive film (ITO) is the main material for producing transparent conductive films, but indium tin oxide lacks flexibility and is prone to cracking under repeated bending, and is fragile, which limits its application in the field of curved screens.

[0003] A flexible transparent conductive film prepared from one-dimensional nanowire materials such as silver nanowires or carbon nanotubes has better photoelectric and bendable performance than an ITO film, and the material source is extensive, and large-size, low-cost preparation can be achieved by using a solution method, and is expected to be widely used in flexible electronic devices. However, in the conductive network composed of silver nanowires, the nanowires are overlapped with each other, resulting in a large resistance at the contact, and the heat generated at the overlapping part can only be conducted along the nanowires, which will damage the nanowires when the heating film power is too high, causing the heating film to fail. Patent CN106782769A discloses a flexible transparent conductive composite film with low roughness and low sheet resistance and a preparation method thereof. The film has a three-layer composite structure, the bottom layer is a transparent polymer film, the middle layer is a conductive network composed of metal nanowires, and the top layer is a transparent conductive layer uniformly covering the transparent polymer film and the conductive network. Although the roughness and sheet resistance are reduced, the manufacturing cost is increased. Therefore, it is necessary to provide a new flexible transparent conductive polymer film suitable for a curved display screen and a preparation process thereof to solve the above problems. SUMMARY

[0004] The present application aims to provide a flexible transparent conductive polymer film suitable for a curved display screen and a preparation process thereof. By compounding the silver ammonia solution of silver nanowires and combining with a hydrophilic flexible polymer substrate, the silver nanoparticles generated in situ are doped in the silver nanowires, which also serves to connect the silver nanowires and the substrate, thereby improving the conductivity and adhesion of the conductive layer.

[0005] To achieve the above-mentioned purpose, the present application provides a preparation process of a flexible transparent conductive polymer film suitable for a curved display screen, comprising the following steps:

[0006] S1, preparing a silver ammonia solution containing silver nanowires;

[0007] S2, forming a film of the silver ammonia solution containing silver nanowires on a hydrophilic flexible polymer substrate;

[0008] S3, performing reduction treatment on the film obtained in step S2 to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0009] Further, the concentration of the silver ammonia solution is 0.01-0.5 mol / L, and the mass ratio of the silver nanowires to silver ions in the silver ammonia solution is (1.5-4):1, preferably 2-3:1.

[0010] Further, the silver nanowires have a diameter of 20-30 nm and a length of 20-30 μm.

[0011] Further, the hydrophilic flexible polymer substrate is an acrylic modified polysiloxane substrate.

[0012] Further, the acrylic modified polysiloxane substrate is prepared by grafting polyvinyl siloxane with acrylic acid to obtain acrylic modified polysiloxane, dissolving the acrylic modified polysiloxane in chloroform, and then coating the solution on a glass substrate to form a film to obtain the acrylic modified polysiloxane substrate.

[0013] Further, the polyvinyl siloxane has a vinyl molar content of 4-8%, and the acrylic modified polysiloxane substrate has a thickness of 80-200 μm.

[0014] Further, step S2 comprises: immersing the hydrophilic flexible polymer substrate in the silver ammonia solution containing silver nanowires for 5-15 min, and then taking it out and drying to obtain a hydrophilic flexible polymer composite metal film.

[0015] Further, step S3 comprises: immersing the film obtained in step S2 in a reducing solution for reduction treatment, and the silver complex is reduced to silver nanoparticles.

[0016] Further, the reducing solution is a glucose solution.

[0017] The application also provides a flexible transparent conductive polymer film suitable for a curved display screen and prepared by the preparation process of any one of the above.

[0018] Overall, compared with the prior art, the above technical solutions conceived by the application mainly have the following technical advantages:

[0019] 1. The flexible transparent conductive polymer film suitable for a curved display screen provided by the present application, by compounding silver ammonia solution of silver nanowires, combining with a hydrophilic flexible polymer substrate, using in-situ generated silver nanoparticles doped in silver nanowires, and simultaneously playing a role of connecting silver nanowires and the substrate, thereby improving the conductivity and adhesion of the conductive layer.

[0020] 2. The present application regulates the content of silver nanowires and silver nanoparticles to make the conductive network structure more perfect, and can ensure the load firmness and reduce the resistance. The carboxyl group of acrylic acid improves the electrostatic adsorption of silver complex ions, so that the silver nanowires and the reduced silver nanoparticles can be relatively regular and fixed-point distributed, and the generated silver nanoparticles have a solid load effect on the silver nanowires. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The sheet resistance of Example 1 and Comparative Example 1 changes with the number of bending times. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0023] The present application provides a preparation process of a flexible transparent conductive polymer film suitable for a curved display screen, comprising the following steps:

[0024] S1, preparing silver ammonia solution containing silver nanowires;

[0025] S2, forming a film of the silver ammonia solution containing silver nanowires on a hydrophilic flexible polymer substrate;

[0026] S3, reducing the film obtained in step S2 to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0027] Through the above technical scheme, by compounding silver ammonia solution of silver nanowires, combining with a hydrophilic flexible polymer substrate, using in-situ generated silver nanoparticles doped in silver nanowires, and simultaneously playing a role of connecting silver nanowires and the substrate, thereby improving the conductivity and adhesion of the conductive layer.

[0028] The concentration of the silver ammine solution is 0.01-0.5 mol / L, and the mass ratio of the silver nanowires to silver ions in the silver ammine solution is (1.5-4):1. The relative amount of the silver nanowires and the silver ammine solution has a direct influence on the conductivity of the conductive polymer film, and by adjusting the content of the silver nanowires and the silver nanoparticles, the conductive network structure is more perfect, and the load firmness can be ensured and the resistance is reduced.

[0029] The diameter of the silver nanowires is 20-30 nm, and the length is 20-30 μm.

[0030] The hydrophilic flexible polymer substrate is an acrylic modified polysiloxane substrate. The carboxyl group of the acrylic acid improves the electrostatic adsorption to the silver complex ions, so that the silver nanowires and the silver nanoparticles obtained by reduction can be relatively regularly and fixedly distributed, and the generated silver nanoparticles have a solidification effect on the silver nanowires.

[0031] The preparation method of the acrylic modified polysiloxane substrate is that: polyvinyl siloxane is subjected to grafting reaction with acrylic acid to obtain acrylic modified polysiloxane, the acrylic modified polysiloxane is dissolved in chloroform, and then is scraped and coated on a glass substrate to form a film to obtain the acrylic modified polysiloxane substrate. The molar content of the vinyl group of the polyvinyl siloxane is 4-8% (the molar amount of the vinyl-containing segment accounts for the molar amount of the whole molecular chain), and the molar ratio of the addition amount of the acrylic acid to the vinyl group is (1-1.2):1.

[0032] The thickness of the acrylic modified polysiloxane substrate is 80-200 μm.

[0033] Step S2 comprises: soaking the hydrophilic flexible polymer substrate in the silver ammine solution containing silver nanowires for 5-15 min, and then taking out and drying to obtain a hydrophilic flexible polymer composite metal film.

[0034] Step S3 comprises: soaking the film obtained in step S2 in a reducing solution for reduction treatment, and the silver complex is reduced into silver nanoparticles. The reducing solution is a glucose solution.

[0035] The application further provides a flexible transparent conductive polymer film suitable for a curved display screen and prepared by the preparation process.

[0036] Example 1

[0037] A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps:

[0038] S1, preparing a silver ammine solution containing silver nanowires: the concentration of the silver ammine solution is 0.1 mol / L (calculated by the silver content), the mass ratio of the silver nanowires to silver ions in the silver ammine solution is 2:1, the diameter of the silver nanowires is 30 nm, and the length is 30 μm.

[0039] S2, the polyvinyl siloxane (vinyl molar content of 6%) is subjected to a free radical grafting reaction with acrylic acid under the action of a catalyst (the molar ratio of the addition amount of acrylic acid to the vinyl group is 1.1:1), to obtain an acrylic-modified polysiloxane, the acrylic-modified polysiloxane is dissolved in chloroform, and then is coated on a glass substrate to form a film, to obtain an acrylic-modified polysiloxane substrate with a thickness of 100 μm.

[0040] The acrylic-modified polysiloxane substrate is immersed in a silver ammonia solution containing silver nanowires for 10 min, and then is taken out and dried, to obtain a hydrophilic flexible polymer composite metal film.

[0041] S3, the film obtained in step S2 is immersed in a glucose solution for reduction treatment, to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0042] Example 2

[0043] A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps:

[0044] S1, a silver ammonia solution containing silver nanowires is prepared: the concentration of the silver ammonia solution is 0.1 mol / L (calculated based on the silver content), the mass ratio of the silver nanowires to the silver ions in the silver ammonia solution is 3:1, the diameter of the silver nanowires is 30 nm, and the length of the silver nanowires is 30 μm.

[0045] S2, the polyvinyl siloxane (vinyl molar content of 6%) is subjected to a free radical grafting reaction with acrylic acid under the action of a catalyst (the molar ratio of the addition amount of acrylic acid to the vinyl group is 1.1:1), to obtain an acrylic-modified polysiloxane, the acrylic-modified polysiloxane is dissolved in chloroform, and then is coated on a glass substrate to form a film, to obtain an acrylic-modified polysiloxane substrate with a thickness of 100 μm.

[0046] The acrylic-modified polysiloxane substrate is immersed in a silver ammonia solution containing silver nanowires for 10 min, and then is taken out and dried, to obtain a hydrophilic flexible polymer composite metal film.

[0047] S3, the film obtained in step S2 is immersed in a glucose solution for reduction treatment, to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0048] Example 3

[0049] A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps:

[0050] S1, prepare a silver ammine solution containing silver nanowires: the concentration of the silver ammine solution is 0.1 mol / L (calculated by silver content), the mass ratio of silver nanowires to silver ions in the silver ammine solution is 2:1, the diameter of the silver nanowires is 30 nm, and the length of the silver nanowires is 30 μm.

[0051] S2, perform a free radical grafting reaction of polyvinylsiloxane (with a vinyl molar content of 8%) and acrylic acid under the action of a catalyst (the molar ratio of the added amount of acrylic acid to the vinyl group is 1.1:1) to obtain acrylic-modified polysiloxane, dissolve the acrylic-modified polysiloxane in chloroform, then perform blade coating on a glass substrate to form a film, and obtain an acrylic-modified polysiloxane substrate with a thickness of 100 μm.

[0052] S3, perform a reduction treatment on the film obtained in step S2 by immersing it in a glucose solution to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0053] S3, perform a reduction treatment on the film obtained in step S2 by immersing it in a glucose solution to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0054] Example 4

[0055] A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps:

[0056] S1, prepare a silver ammine solution containing silver nanowires: the concentration of the silver ammine solution is 0.1 mol / L (calculated by silver content), the mass ratio of silver nanowires to silver ions in the silver ammine solution is 4:1, the diameter of the silver nanowires is 30 nm, and the length of the silver nanowires is 30 μm.

[0057] S2, perform a free radical grafting reaction of polyvinylsiloxane (with a vinyl molar content of 6%) and acrylic acid under the action of a catalyst (the molar ratio of the added amount of acrylic acid to the vinyl group is 1.1:1) to obtain acrylic-modified polysiloxane, dissolve the acrylic-modified polysiloxane in chloroform, then perform blade coating on a glass substrate to form a film, and obtain an acrylic-modified polysiloxane substrate with a thickness of 100 μm.

[0058] S3, perform a reduction treatment on the film obtained in step S2 by immersing it in a glucose solution to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0059] S3, perform a reduction treatment on the film obtained in step S2 by immersing it in a glucose solution to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0060] Example 5

[0061] A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps:

[0062] S1, preparing a silver ammonia solution containing silver nanowires: the concentration of the silver ammonia solution is 0.1 mol / L (calculated by silver content), the mass ratio of silver nanowires to silver ions in the silver ammonia solution is 2:1, the diameter of the silver nanowires is 30 nm, and the length of the silver nanowires is 30 μm.

[0063] S2, performing a free radical grafting reaction of polyvinylsiloxane (vinyl molar content of 4%) and acrylic acid under the action of a catalyst (the addition amount of acrylic acid and the molar ratio of vinyl are 1.1:1) to obtain acrylic-modified polysiloxane, dissolving the acrylic-modified polysiloxane in chloroform, and then scraping and coating on a glass substrate to form a film to obtain an acrylic-modified polysiloxane substrate with a thickness of 100 μm.

[0064] Soaking the acrylic-modified polysiloxane substrate in the silver ammonia solution containing silver nanowires for 10 min, and then taking it out and drying to obtain a hydrophilic flexible polymer composite metal film.

[0065] S3, soaking the film obtained in step S2 in a glucose solution for reduction treatment to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0066] Comparative Example 1

[0067] A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps:

[0068] S1, preparing a silver ammonia solution containing silver nanowires: the concentration of the silver ammonia solution is 0.1 mol / L (calculated by silver content), the mass ratio of silver nanowires to silver ions in the silver ammonia solution is 2:1, the diameter of the silver nanowires is 30 nm, and the length of the silver nanowires is 30 μm.

[0069] S2, scraping and coating polydimethylsiloxane on a glass substrate to form a film to obtain a polydimethylsiloxane substrate with a thickness of 100 μm.

[0070] Soaking the polydimethylsiloxane substrate in the silver ammonia solution containing silver nanowires for 10 min, and then taking it out and drying to obtain a flexible polymer composite metal film.

[0071] S3, soaking the film obtained in step S2 in a glucose solution for reduction treatment to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

[0072] The samples of Examples 1-3 and Comparative Examples 1-3 were subjected to sheet resistance testing before and after bending, wherein the bending was a 2 mm radius of curvature and was cycled 50 times.

[0073] Sheet resistance test results of Example 1-5 and Comparative Example 1

[0074]

[0075] As can be seen from Table 1, when the silver ammine solution content is too low, the sheet resistance increases, and the sheet resistance change rate after bending is higher, indicating that the generated silver nanoparticles help to improve the bending resistance of the conductive layer. When the vinyl content is too low, the grafted carboxyl group also decreases, which affects the site generation of silver nanoparticles, resulting in an increase in sheet resistance and a decrease in bending resistance. From the above, it can be seen that the silver ammine solution content and the vinyl content of the substrate are important factors affecting the bending resistance of the conductive layer. Figure 1 As can be seen, Example 1 is cycled with a curvature radius of 2mm for 50 times, and the sheet resistance change rate is still small, indicating good bending resistance, while Comparative Example 1 has a significant increase in sheet resistance after bending more than 20 times, indicating that when the substrate does not contain acrylic groups, the silver nanoparticles of the silver nanowire are not uniformly arranged, and the growth of the silver nanoparticles is affected, resulting in a significant decrease in bending resistance.

[0076] Those skilled in the art will readily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of a flexible transparent conductive polymer film suitable for use in curved display screens, characterised in that, The method comprises the following steps: A flexible transparent conductive polymer film suitable for a curved display screen is prepared by the following steps: S1, preparing a silver ammonia solution containing silver nanowires: the concentration of the silver ammonia solution is 0.1 mol / L, the mass ratio of the silver nanowires to silver ions in the silver ammonia solution is 2:1, the diameter of the silver nanowires is 30 nm, and the length of the silver nanowires is 30 μm; S2, performing a free radical grafting reaction of polyvinyl siloxane and acrylic acid under the action of a catalyst to obtain acrylic acid modified polysiloxane, dissolving the acrylic acid modified polysiloxane in chloroform, then performing blade coating on a glass substrate to form a film, and obtaining an acrylic acid modified polysiloxane substrate with a thickness of 100 μm; the molar content of the vinyl group of the polyvinyl siloxane is 6%, and the molar ratio of the addition amount of the acrylic acid to the vinyl group is 1.1:1; immersing the acrylic acid modified polysiloxane substrate in the silver ammonia solution containing silver nanowires for 10 min, then taking out and drying to obtain a hydrophilic flexible polymer composite metal film; S3, immersing the film obtained in step S2 in a glucose solution for reduction treatment to obtain a silver nanoparticle and silver nanowire composite flexible transparent conductive polymer film.

2. The flexible transparent conductive polymer film suitable for a curved display screen obtained by the preparation process of claim 1.

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