CN117979673A - A kind of anticorrosion transparent electromagnetic shielding film and its preparation method and application - Google Patents

Abstract

The present invention discloses an anti-corrosion transparent electromagnetic shielding film and its preparation method and application, which relate to the field of electromagnetic shielding technology. The transparent electromagnetic shielding film comprises a first dielectric layer, a conductive layer, a second dielectric layer and a substrate which are stacked in sequence from top to bottom; the first dielectric layer comprises one or more of indium tin oxide, zinc oxide, aluminum oxide, and zirconium dioxide; the second dielectric layer comprises one or more of indium tin oxide, zinc oxide, aluminum oxide, silicon dioxide, and titanium dioxide. The present invention introduces multiple interfaces into the transparent conductive multilayer structure on the surface of the substrate, which can achieve multiple reflection losses of electromagnetic waves and achieve the best shielding effect.

Description

A kind of anticorrosive transparent electromagnetic shielding film and its preparation method and application

Technical Field

The invention relates to the technical field of electromagnetic shielding, and in particular to an anti-corrosion transparent electromagnetic shielding film and a preparation method and application thereof.

Background technique

The continuous development and replacement of electromagnetic wave technology has made the electromagnetic space environment increasingly complex. Under the disorderly competition development mode of various electromagnetic facilities, the total energy of electromagnetic spectrum radiation on the earth's surface has increased sharply, and spectrum conflicts have increased sharply, resulting in a sharp deterioration of the electromagnetic environment. The complexity of the electromagnetic environment has brought about serious electromagnetic radiation pollution problems. Among them, the most important electromagnetic interference activities will not only affect the normal use and privacy protection of electronic equipment, but also cause irreversible damage and harm to the human nervous system and organs such as the heart and muscles. In response to the current electromagnetic radiation pollution problem, electromagnetic shielding technology has received close attention and research. However, how to achieve the electromagnetic shielding goal at the optical window has become a hot topic and difficulty in research.

Since light and microwaves are both electromagnetic waves, the essence of transparent electromagnetic shielding is to achieve the passband of the optical band and the stopband of the microwave band. Therefore, the research on electromagnetic shielding materials with good visible light transmittance and excellent electromagnetic shielding performance is hot and emerging in an endless stream. Transparent electromagnetic shielding materials are composed of a substrate, a conductive layer and an anti-reflection layer, wherein the electrical properties of the conductive layer are the key factors determining the electromagnetic shielding effectiveness of the film, and the n and k coefficients of the anti-reflection layer affect the transmittance of the final film in the visible light band. Technicians in this field adopt a zinc oxide/silver/zinc oxide multilayer structure design, and obtain an electromagnetic shielding effectiveness of up to 32dB in the X-band while obtaining a high transmittance of 90%. The prior art proposes a nickel-plated silver nanowire-based film, and the final transparent electromagnetic shielding film material has a transmittance of 78.1% at 550nm, and the electromagnetic shielding effectiveness changes before and after corrosion are 20.01dB and 16.62dB, but the scheme still has the problems of insufficient shielding effectiveness and low transmittance. The nanoscale metal silver films reported so far have high chemical activity and are prone to oxidation and failure in harsh environments (oceans, polar regions, etc.). There are still gaps and deficiencies in the research on their environmental stability. Current technologies generally use the following methods to improve the corrosion resistance of metal silver films: (1) By coating the outer layer with polymers such as various resins, the effect of rejecting external corrosion can be achieved, but the thickness of the film after coating increases significantly, and the advantage of being "thin" is lost. (2) By doping with inhibitors with higher surface energy, the stable growth of the metal film is achieved, and a more dense and flat conductive layer is obtained. The weather resistance in the gas environment is acceptable, but once immersed in a corrosive solution, its surface will adsorb water and oxygen molecules and be corroded and fail.

Therefore, developing a transparent conductive film with broadband, high strength, high transmittance and corrosion resistance in the radar band has become a technical problem that needs to be urgently solved in this field.

Summary of the invention

In view of the deficiencies in the above-mentioned background technology, the present invention mainly solves the problems of insufficient shielding efficiency and low light transmittance of materials in the prior art, as well as the problem of being easily oxidized and failing in harsh environments. The present invention provides an anti-corrosion transparent electromagnetic shielding film and its preparation method and application. The transparent conductive multilayer structure of the film on the surface of the substrate introduces multiple interfaces, which can achieve multiple reflection losses of electromagnetic waves and achieve the best shielding effect.

The first object of the present invention is to provide an anti-corrosion transparent electromagnetic shielding film, the transparent electromagnetic shielding film comprising a first dielectric layer, a conductive layer, a second dielectric layer and a substrate stacked in sequence from top to bottom;

The first dielectric layer includes one or more of indium tin oxide, zinc oxide, aluminum oxide, and zirconium dioxide; the second dielectric layer includes one or more of indium tin oxide, zinc oxide, aluminum oxide, silicon dioxide, and titanium dioxide.

Preferably, the thickness of the first dielectric layer is 35-55 nm; the thickness of the second dielectric layer is 40-60 nm.

Preferably, the conductive layer is one or more of silver, copper, gold, platinum, aluminum, and iron; and the thickness of the conductive layer is 8 to 12 nm.

Preferably, the substrate is float glass, polymethyl methacrylate or quartz glass.

Preferably, the transparent electromagnetic shielding film further comprises a surface hydrophobic layer, and the surface hydrophobic layer is arranged on the first dielectric layer.

Preferably, the surface hydrophobic layer is one or more of polydimethylsiloxane, polyacrylate, and polytetrafluoroethylene; and the thickness of the surface hydrophobic layer is 1-100 μm.

The second object of the present invention is to provide a method for preparing an anti-corrosion transparent electromagnetic shielding film, comprising the following steps: sequentially preparing a second dielectric layer, a conductive layer and a first dielectric layer on a substrate by magnetron sputtering; before use, the substrate is ultrasonically cleaned in acetone, alcohol and deionized water, respectively, and dried in a vacuum oven.

The third object of the present invention is to provide a method for preparing an anti-corrosion transparent electromagnetic shielding film, comprising the following steps: preparing a second dielectric layer, a conductive layer and a first dielectric layer in sequence on a substrate by magnetron sputtering; preparing a surface hydrophobic layer on the surface of the first dielectric layer by spin coating; before use, the substrate is ultrasonically cleaned in acetone, alcohol and deionized water, respectively, and dried in a vacuum oven.

The fourth object of the present invention is to provide an application of an anti-corrosion transparent electromagnetic shielding film in an electronic touch screen.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention provides an anti-corrosion transparent electromagnetic shielding film and a preparation method and application thereof. The present invention obtains an anti-corrosion transparent electromagnetic shielding film by stacking a first dielectric layer, a conductive layer, and a second dielectric layer sequentially from top to bottom on a substrate. The conductive layer can achieve effective loss of electromagnetic waves in the radar band of 8GHz to 18GHz to achieve electromagnetic shielding performance. The first dielectric layer and the second dielectric layer regulate the reflection behavior of the conductive layer in the visible light range to ensure the observation effect of the transparent conductive film. At the same time, the second dielectric layer as a transition layer can improve the three-dimensional island growth mode of the conductive layer, improve the strong adhesion, chemical stability and nucleation seed characteristics of the conductive layer film to the substrate, and the first dielectric layer can achieve the effect of increasing transmittance and reducing reflection based on the principle of interference destructiveness.

The present invention also provides a surface hydrophobic layer on the first dielectric layer to prepare an anti-corrosion transparent electromagnetic shielding film, and obtains a multilayer structure of surface hydrophobic layer/first dielectric layer/conductive layer/second dielectric layer. The surface hydrophobic layer can isolate the water and oxygen environment and improve the environmental stability of the transparent electromagnetic shielding function. Compared with the existing electromagnetic shielding coating materials, the transparent electromagnetic shielding film material provided by the present invention has the advantages of excellent electromagnetic shielding performance, good light transmittance, corrosion resistance and low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of an electromagnetic shielding film provided by the present invention without being coated with a surface hydrophobic layer.

FIG. 2 is a schematic structural diagram of an electromagnetic shielding film coated with a surface hydrophobic layer provided by the present invention.

FIG3 is a comparison curve of the shielding effectiveness of the anti-corrosion transparent electromagnetic shielding films provided in Example 1, Example 6 and Example 7.

FIG4 is a comparison curve of the actual visible light transmittance of the anti-corrosion transparent electromagnetic shielding films provided in Example 1, Example 6 and Example 7.

FIG5 is a bar graph showing the water contact angles of the anti-corrosion transparent electromagnetic shielding films provided in Example 1 and Example 4.

Figure 6 is an electrochemical performance diagram of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and Example 4; wherein (a), (b), (c), and (d) in Figure 6 are the Nyquist diagram, Bode mode diagram, Bode phase diagram, and potential polarization curve diagram of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and Example 4, respectively.

FIG. 7 is a partial enlarged view of FIG. 6 (a).

Detailed ways

In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

The present invention discloses a corrosion-resistant transparent electromagnetic shielding film and a preparation method thereof. Indium tin oxide, silver, and an indium tin oxide nanofilm are sequentially deposited on a transparent substrate, and then a polydimethylsiloxane hydrophobic film is spin-coated on the surface to protect the transparent conductive layer, thereby preparing a corrosion-resistant transparent electromagnetic shielding film. The method of the present invention can not only realize the electromagnetic shielding function, but also effectively solve the problem of high reflectivity of the metal silver film in the visible light band. The product of the present invention has excellent corrosion resistance, effectively improves the service life of the transparent electromagnetic shielding material at the optical window, and is expected to be applied in the direction of electromagnetic shielding protection of the outer layer of electronic equipment.

1 , the first aspect of the present invention provides an anti-corrosion transparent electromagnetic shielding film, the transparent electromagnetic shielding film comprising a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked sequentially from top to bottom;

The first dielectric layer 1 includes one or more of indium tin oxide (ITO), zinc oxide, aluminum oxide, and zirconium dioxide; the second dielectric layer 3 includes one or more of indium tin oxide (ITO), zinc oxide, aluminum oxide, silicon dioxide, and titanium dioxide. The first dielectric layer 1 has a thickness of 35-55 nm; the second dielectric layer 3 has a thickness of 40-60 nm.

The conductive layer 2 is one or more of silver, copper, gold, platinum, aluminum, and iron; the thickness of the conductive layer 2 is 8-12 nm.

In the present invention, at least the sheet resistance of the transparent conductive layer 2 on the substrate surface must be less than 10Ω/Sq, preferably 5Ω/Sq. The substrate 4 is float glass, polymethyl methacrylate or quartz glass.

As shown in FIG. 2 , the transparent electromagnetic shielding film further includes a surface hydrophobic layer 5 , and the surface hydrophobic layer 5 is disposed on the first dielectric layer 1 .

The surface hydrophobic layer 5 is one or more of polydimethylsiloxane, polyacrylate, and polytetrafluoroethylene; the thickness of the surface hydrophobic layer 5 is 1-100 μm.

In the present invention, it is at least necessary to ensure that the transmittance of the surface hydrophobic layer at 550nm is greater than 80%, preferably greater than 90%; the hydrophobic angle is greater than 90°, preferably greater than 105°.

In one embodiment, the transparent conductive multilayer structure on the surface of the substrate introduces multiple interfaces, which can achieve multiple reflection losses of electromagnetic waves and achieve the best shielding effect. In addition, the thickness of the first dielectric layer/conductive layer/second dielectric layer system is optimized, and when the reflected wave meets the interference destructive effect, the effect of increasing transmittance and reducing reflection in the visible light band can be achieved, and the high requirements for the optoelectronic performance of the thin film material (the sheet resistance of the thin film is less than 10 ohms and the transmittance is more than 90%) can be achieved in coordination.

The second aspect of the present invention provides a method for preparing an anti-corrosion transparent electromagnetic shielding film, comprising the following steps: preparing a second dielectric layer, a conductive layer and a first dielectric layer in sequence on a substrate by magnetron sputtering; before use, the substrate is ultrasonically cleaned in acetone, alcohol and deionized water, respectively, and dried in a vacuum oven.

The third aspect of the present invention provides a method for preparing an anti-corrosion transparent electromagnetic shielding film, comprising the following steps: preparing a second dielectric layer, a conductive layer and a first dielectric layer in sequence on a substrate by magnetron sputtering; preparing a surface hydrophobic layer on the surface of the first dielectric layer by spin coating; before use, ultrasonically cleaning the substrate in acetone, alcohol and deionized water, respectively, and drying it in a vacuum oven.

A fourth aspect of the present invention provides an application of an anti-corrosion transparent electromagnetic shielding film in an electronic touch screen.

It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.

Example 1

As shown in Figure 1, an anti-corrosion transparent electromagnetic shielding film includes a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked in sequence from top to bottom; the thickness of the first dielectric layer is 40nm, the thickness of the second dielectric layer is 44nm; the thickness of the conductive layer is 8nm.

The substrate 4 is a quartz glass substrate of 30 mm×30 mm; the first dielectric layer 1 is made of ITO; the conductive layer 2 is made of Ag; and the second dielectric layer 3 is made of ITO.

The specific preparation method comprises the following steps:

First, a 30 mm × 30 mm quartz glass substrate was ultrasonically cleaned in deionized water, acetone and anhydrous ethanol for 10 min, and then dried in a vacuum oven. The second dielectric layer, the conductive layer and the first dielectric layer were sequentially deposited on the substrate surface by magnetron sputtering.

In this embodiment, both the first dielectric layer and the second dielectric layer are made of ITO, the power source of magnetron sputtering is a radio frequency power source with a power of 100W, the thickness of the first dielectric layer is 40nm, and the thickness of the second dielectric layer is 44nm;

The conductive layer is made of Ag, the power supply of magnetron sputtering is a DC power supply with a power of 50W, and the thickness of the Ag layer is 8nm.

All sputterings were performed under an argon atmosphere with a gas flow rate controlled at 32 Sccm.

The obtained anti-corrosion transparent electromagnetic shielding film is referred to as ITO/Ag/ITO (IAI), and the specifications are first dielectric layer/conductive layer/second dielectric layer (40nm/8nm/44nm).

The electromagnetic shielding film obtained in this embodiment was tested under the following test conditions: the surface square resistance of the film was measured by the four-probe method; the electromagnetic shielding performance was measured by a vector network analyzer (Agilent Technologies E8362B), with a test frequency range of 8 to 18 GHz; and the visible light transmittance was measured by a UV-visible-near infrared spectrophotometer (PerkinElmer Lambda1050+). The electrochemical test was performed by an electrochemical workstation (CS310X multi-channel electrochemical workstation) to obtain the test results, with a working area of 1×1 cm ² . The results are shown in Figures 3, 4 and 5 .

Example 2

As shown in Figure 1, an anti-corrosion transparent electromagnetic shielding film includes a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked in sequence from top to bottom; the thickness of the first dielectric layer is 40nm, the thickness of the second dielectric layer is 44nm; the thickness of the conductive layer is 10nm.

The substrate 4 is a quartz glass substrate of 30 mm×30 mm; the first dielectric layer 1 is made of ITO; the conductive layer 2 is made of Ag; and the second dielectric layer 3 is made of ITO.

The specific preparation method comprises the following steps:

First, a 30 mm × 30 mm quartz glass substrate was ultrasonically cleaned in deionized water, acetone and anhydrous ethanol for 10 min, and then dried in a vacuum oven. The second dielectric layer, the conductive layer and the first dielectric layer were sequentially deposited on the substrate surface by magnetron sputtering.

In this embodiment, both the first dielectric layer and the second dielectric layer are made of ITO, the power supply of magnetron sputtering is a radio frequency power supply with a power of 100 W, the thickness of the first dielectric layer is 40 nm, and the thickness of the second dielectric layer is 44 nm.

The conductive layer is made of Ag, the power supply of magnetron sputtering is a DC power supply with a power of 50W, and the thickness of the Ag layer is 10nm.

All sputterings were performed under an argon atmosphere with a gas flow rate controlled at 32 Sccm.

The obtained anti-corrosion transparent electromagnetic shielding film is referred to as ITO/Ag/ITO (IAI), and its specifications are first dielectric layer/conductive layer/second dielectric layer (40nm/10nm/44nm).

The electromagnetic shielding film obtained in this example was tested under the following test conditions: the electromagnetic shielding performance was tested by a vector network analyzer (Agilent Technologies E8362B) with a test frequency range of 2 to 18 GHz; the visible light transmittance was tested by a UV-visible-near infrared spectrophotometer (PerkinElmer Lambda 1050+). The electrochemical test was performed by an electrochemical workstation (CS310X multi-channel electrochemical workstation) with a working area of 1×1 cm ² .

After testing, the transparent electromagnetic shielding film prepared in this embodiment has a square resistance of ≈6.45Ω/Sq, a transmittance of 87.83% at a wavelength of 550nm, an average electromagnetic shielding effectiveness of 30dB at 8-18GHz, and a self-corrosion potential and a self-corrosion current of -0.43179V and -8.75A, respectively.

Example 3

As shown in Figure 1, an anti-corrosion transparent electromagnetic shielding film includes a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked in sequence from top to bottom; the thickness of the first dielectric layer is 40nm, the thickness of the second dielectric layer is 44nm; the conductive layer is 12nm.

The substrate 4 is a quartz glass substrate of 30 mm×30 mm; the first dielectric layer 1 is made of ITO; the conductive layer 2 is made of Ag; and the second dielectric layer 3 is made of ITO.

The specific preparation method comprises the following steps:

First, a 30 mm × 30 mm quartz glass substrate was ultrasonically cleaned in deionized water, acetone and anhydrous ethanol for 10 min, and then dried in a vacuum oven. The second dielectric layer, the conductive layer and the first dielectric layer were sequentially deposited on the substrate surface by magnetron sputtering.

In this embodiment, both the first dielectric layer and the second dielectric layer are made of ITO, the power source of magnetron sputtering is a radio frequency power source with a power of 100W, the thickness of the first dielectric layer is 40nm, and the thickness of the second dielectric layer is 44nm;

The conductive layer is made of Ag, the power supply of magnetron sputtering is a DC power supply with a power of 50W, and the thickness of the Ag layer is 12nm.

All sputterings were performed under an argon atmosphere with a gas flow rate controlled at 32 Sccm.

The obtained anti-corrosion transparent electromagnetic shielding film is referred to as ITO/Ag/ITO (IAI), and the specifications are first dielectric layer/conductive layer/second dielectric layer (40nm/12nm/44nm).

The electromagnetic shielding film obtained in this example was tested under the following test conditions: the electromagnetic shielding performance was tested by a vector network analyzer (Agilent Technologies E8362B) with a test frequency range of 2 to 18 GHz; the visible light transmittance was tested by a UV-visible-near infrared spectrophotometer (PerkinElmer Lambda 1050+). The electrochemical test was performed by an electrochemical workstation (CS310X multi-channel electrochemical workstation) with a working area of 1×1 cm ² .

After testing, the transparent electromagnetic shielding film prepared in this embodiment has a square resistance of ≈6.06Ω/Sq, a transmittance of 91.56% at a wavelength of 550nm, an average electromagnetic shielding effectiveness of 38dB at 8-18GHz, and a self-corrosion potential and a self-corrosion current of -0.40349V and -8.5A, respectively.

Example 4

As shown in Figure 2, an anti-corrosion transparent electromagnetic shielding film includes a surface hydrophobic layer 5, a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked in sequence from top to bottom; the thickness of the first dielectric layer is 40nm, the thickness of the second dielectric layer is 44nm; the conductive layer is 8nm; the thickness of the surface hydrophobic layer is 36μm.

The substrate 4 is a quartz glass substrate of 30 mm×30 mm; the first dielectric layer 1 is made of ITO; the conductive layer 2 is made of Ag; the second dielectric layer 3 is made of ITO; and the surface hydrophobic layer 5 is polydimethylsiloxane (PDMS).

The specific preparation method comprises the following steps:

First, a 30 mm × 30 mm quartz glass substrate was ultrasonically cleaned in deionized water, acetone and anhydrous ethanol for 10 min, and then dried in a vacuum oven. The second dielectric layer, the conductive layer and the first dielectric layer were sequentially deposited on the substrate surface by magnetron sputtering.

In this embodiment, both the first dielectric layer and the second dielectric layer are made of ITO, the power source of magnetron sputtering is a radio frequency power source with a power of 100W, the thickness of the first dielectric layer is 40nm, and the thickness of the second dielectric layer is 44nm;

The conductive layer is made of Ag, the power supply of magnetron sputtering is a DC power supply with a power of 50W, and the thickness of the Ag layer is 8nm.

Finally, an ultra-thin polydimethylsiloxane surface hydrophobic layer was prepared on the surface of the first dielectric layer by spin coating at a rotation speed of 1670 r/min and a spin coating time of 18 s. The film was cured at 80 °C for 24 h to obtain an anti-corrosion transparent conductive film, referred to as PDMS/ITO/Ag/ITO, with specifications of surface hydrophobic layer/first dielectric layer/conductive layer/second dielectric layer (PDMS/40nm/8nm/44nm).

After testing, the corrosion-resistant transparent electromagnetic shielding film prepared in this embodiment has a transmittance of 88.08% at 550nm, an average electromagnetic shielding effectiveness of 34dB in the range of 8-18GHz, and a self-corrosion potential and a self-corrosion current of -0.351V and -10.5A, respectively.

Example 5

As shown in Figure 1, an anti-corrosion transparent electromagnetic shielding film includes a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked in sequence from top to bottom; the thickness of the first dielectric layer is 40nm, the thickness of the second dielectric layer is 44nm; the thickness of the conductive layer is 8nm.

The substrate 4 is a quartz glass substrate of 30 mm×30 mm; the first dielectric layer 1 is made of ZnO; the conductive layer 2 is made of Cu; and the second dielectric layer 3 is made of ZnO.

The specific preparation method comprises the following steps:

First, a 30 mm × 30 mm quartz glass substrate was ultrasonically cleaned in deionized water, acetone and anhydrous ethanol for 10 min, and then dried in a vacuum oven. The second dielectric layer, the conductive layer and the first dielectric layer were sequentially deposited on the substrate surface by magnetron sputtering.

In this embodiment, both the first dielectric layer and the second dielectric layer are made of ZnO, the power source of magnetron sputtering is a radio frequency power source with a power of 100 W, the thickness of the first dielectric layer is 40 nm, and the thickness of the second dielectric layer is 44 nm;

The conductive layer is made of Cu, the power supply of magnetron sputtering is a DC power supply with a power of 50W, and the thickness of the Cu layer is 8nm.

All sputterings were performed under an argon atmosphere with a gas flow rate controlled at 32 Sccm.

The obtained anti-corrosion transparent electromagnetic shielding film is referred to as ZnO/Cu/ZnO (IAI), and its specifications are first dielectric layer/conductive layer/second dielectric layer (40nm/8nm/44nm).

The electromagnetic shielding film obtained in this example was tested under the following test conditions: the electromagnetic shielding performance was tested by a vector network analyzer (Agilent Technologies E8362B) with a test frequency range of 2 to 18 GHz; the visible light transmittance was tested by a UV-visible-near infrared spectrophotometer (PerkinElmer Lambda 1050+). The electrochemical test was performed by an electrochemical workstation (CS310X multi-channel electrochemical workstation) with a working area of 1×1 cm ² .

After testing, the square resistance of the transparent electromagnetic shielding film prepared in this embodiment is ≈8.05Ω/Sq, the transmittance at a wavelength of 550nm is 88.20%, the average electromagnetic shielding effectiveness of 8~18GHz is 31dB, and the self-corrosion potential and self-corrosion current are -0.513V and -9.05A respectively.

Example 6

The same as Example 1, except that the thickness of the first dielectric layer is 50 nm, the thickness of the second dielectric layer is 45 nm, and the thickness of the conductive layer is 8 nm.

The obtained anti-corrosion transparent electromagnetic shielding film is referred to as ITO/Ag/ITO (IAI), and the specifications are first dielectric layer/conductive layer/second dielectric layer (50nm/8nm/45nm).

Example 7

The same as Example 1, except that the thickness of the first dielectric layer is 40 nm, the thickness of the second dielectric layer is 50 nm, and the thickness of the conductive layer is 8 nm.

The obtained anti-corrosion transparent electromagnetic shielding film is referred to as ITO/Ag/ITO (IAI), and the specifications are first dielectric layer/conductive layer/second dielectric layer (40nm/8nm/50nm).

Comparative Example 1

A corrosion-resistant transparent electromagnetic shielding film, comprising a first dielectric layer 1, a conductive layer 2, a second dielectric layer 3 and a substrate 4 stacked in sequence from top to bottom; the thickness of the first dielectric layer is 65nm, the thickness of the second dielectric layer is 25nm; the thickness of the conductive layer is 8nm.

The substrate 4 is a quartz glass substrate of 30 mm×30 mm; the first dielectric layer 1 is made of ITO; the conductive layer 2 is made of Ag; and the second dielectric layer 3 is made of ITO.

The specific preparation method comprises the following steps:

First, a 30 mm × 30 mm quartz glass substrate was ultrasonically cleaned in deionized water, acetone and anhydrous ethanol for 10 min, and then dried in a vacuum oven. The second dielectric layer, the conductive layer and the first dielectric layer were sequentially deposited on the substrate surface by magnetron sputtering.

In this comparative example, both the first dielectric layer and the second dielectric layer are made of ITO, the power source of magnetron sputtering is a radio frequency power source with a power of 100 W, the thickness of the first dielectric layer is 65 nm, and the thickness of the second dielectric layer is 25 nm;

The conductive layer is made of Ag, the power supply of magnetron sputtering is a DC power supply with a power of 50W, and the thickness of the Ag layer is 8nm.

All sputterings were performed under an argon atmosphere with a gas flow rate controlled at 32 Sccm.

The electromagnetic shielding film obtained in this comparative example was tested, and the test conditions were as follows: the surface square resistance of the film was tested by the four-probe method; the electromagnetic shielding performance was tested by a vector network analyzer (Agilent Technologies E8362B), and the test frequency range was 8 to 18 GHz; the visible light transmittance was tested by a UV-visible-near infrared spectrophotometer (PerkinElmer Lambda1050+). The electrochemical test was performed by an electrochemical workstation (CS310X multi-channel electrochemical workstation) to obtain the test results, and the working area area was 1×1 cm ^2. The electromagnetic shielding film prepared above was tested, and the test conditions were as follows: the electromagnetic shielding performance was tested by a vector network analyzer (Agilent Technologies E8362B), and the test frequency range was 2 to 18 GHz; the visible light transmittance was tested by a UV-visible-near infrared spectrophotometer (PerkinElmer Lambda 1050+). The electrochemical test was performed by an electrochemical workstation (CS310X multi-channel electrochemical workstation) to obtain the test results, and the working area area was 1×1 cm ² .

After testing, the square resistance of the transparent electromagnetic shielding film prepared in this comparative example is ≈13.05Ω/Sq, the transmittance at a wavelength of 550nm is 87.20%, the average electromagnetic shielding effectiveness of 8~18GHz is 28dB, and the self-corrosion potential and self-corrosion current are -0.407V and -8.05A respectively.

In order to illustrate the relevant performance of the transparent electromagnetic shielding film provided by the present invention, it is described in conjunction with the accompanying drawings.

FIG3 is a comparative curve diagram of the shielding effectiveness of the anti-corrosion transparent electromagnetic shielding films provided in Example 1, Example 6 and Example 7;

As can be seen from Figure 3, the average shielding effectiveness of the single-layer silver film Ag in the X and Ku bands are 23.5dB and 27.5dB, respectively. The shielding effectiveness of the first dielectric layer/conductive layer/second dielectric layer obtained through structural modification is significantly improved in the 8-18GHz band. Among them, when the first dielectric layer is 40nm and the second dielectric layer is 44nm, the average shielding effectiveness in the X and Ku bands reaches the best, which are 32dB and 34dB, respectively. At the same time, the difference in the loss of electromagnetic waves by changing the thickness of the first dielectric layer and the second dielectric layer is because the reflection of electromagnetic waves at the interface between the dielectric layer and the conductive layer and inside the film is different. By comparison, it is found that the sandwich structure proposed in the present invention can greatly improve the shielding effectiveness of a single-layer silver film.

FIG4 is a comparison curve of the actual visible light transmittance of the anti-corrosion transparent electromagnetic shielding films provided in Example 1, Example 6 and Example 7;

As shown in Figure 4, the transmittance of the single-layer silver film Ag at a wavelength of 550nm is about 65%. Compared with the single-layer silver film, after optimizing the thickness of the first dielectric layer and the second dielectric layer, the transmittance of IAI (40nm/8nm/44nm) at 550nm% is measured to be 86.5%, and the optimal transmittance in the visible light band is obtained. It can be seen that the indium tin oxide/silver/indium tin oxide multilayer nanofilm exhibits good optical transparency.

Figure 5 is a bar graph of the water contact angle of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and Example 4; it can be seen from Figure 5 that by testing the water contact angles of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and the anti-corrosion transparent electromagnetic shielding film provided in Example 4, it was found that after the surface was coated with PDMS, the film changed from a hydrophilic state to a hydrophobic state, and the water contact angle was increased from the original 64° to 114°, which gave the film waterproofness and achieved antioxidant protection for the silver film.

Figure 6 is an electrochemical performance diagram of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and Example 4; Figure 7 is a partial enlarged diagram of (a) in Figure 6; wherein, (a), (b), (c), and (d) in Figure 6 are the Nyquist diagram, Bode mode diagram, Bode phase diagram, and potential polarization curve diagram of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and Example 4, respectively.

From Figure 6 (a), the electrochemical behavior of the anti-corrosion transparent electromagnetic shielding film provided in Example 1 and the anti-corrosion transparent electromagnetic shielding film provided in Example 4 in 5% NaCl solution is explored. Combined with Figure 7, it can be seen that the arc radius of the anti-corrosion transparent electromagnetic shielding film provided in Example 4 is greater than the arc radius of the anti-corrosion transparent electromagnetic shielding film provided in Example 1, that is, the anti-corrosion transparent electromagnetic shielding film provided in Example 4 has a larger impedance and exhibits better corrosion resistance. From Figure 6 (b) and (c), it can be seen that the film impedance after spin coating PDMS is larger, which can block the diffusion path of the secondary solution so that it will not directly contact with the highly active corrosive medium, thereby greatly improving its corrosion resistance. At the same time, in order to quantitatively illustrate the corrosion rate of the film, the dynamic potential polarization curve of the film is measured as shown in Figure 6 (d). It is observed that the potential polarization curve of the anti-corrosion transparent electromagnetic shielding film provided in Example 4 is shifted from the upper right compared with the potential polarization curve of the film provided in Example 1, that is, the potential rises and the corrosion current density decreases, that is, the electrochemical corrosion rate slows down, indicating that PDMS has a good corrosion inhibition effect.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. An anti-corrosion transparent electromagnetic shielding film, characterized in that the transparent electromagnetic shielding film comprises a first dielectric layer, a conductive layer, a second dielectric layer and a substrate stacked in sequence from top to bottom; The first dielectric layer includes one or more of indium tin oxide, zinc oxide, aluminum oxide, and zirconium dioxide; the second dielectric layer includes one or more of indium tin oxide, zinc oxide, aluminum oxide, silicon dioxide, and titanium dioxide. 2. The anti-corrosion transparent electromagnetic shielding film according to claim 1 is characterized in that the thickness of the first dielectric layer is 35~55nm; the thickness of the second dielectric layer is 40~60nm. 3. The anti-corrosion transparent electromagnetic shielding film according to claim 1 is characterized in that the conductive layer is one or more of silver, copper, gold, platinum, aluminum, and iron; and the thickness of the conductive layer is 8 to 12 nm. 4. The anti-corrosion transparent electromagnetic shielding film according to claim 1, characterized in that the substrate is float glass, polymethyl methacrylate or quartz glass. 5 . The anti-corrosion transparent electromagnetic shielding film according to claim 1 , characterized in that the transparent electromagnetic shielding film further comprises a surface hydrophobic layer, and the surface hydrophobic layer is arranged on the first dielectric layer. 6. The anti-corrosion transparent electromagnetic shielding film according to claim 5 is characterized in that the surface hydrophobic layer is one or more of polydimethylsiloxane, polyacrylate, and polytetrafluoroethylene; and the thickness of the surface hydrophobic layer is 1~100μm. 7. A method for preparing the anti-corrosion transparent electromagnetic shielding film according to any one of claims 1 to 4, characterized in that it comprises the following steps: sequentially preparing a second dielectric layer, a conductive layer and a first dielectric layer on a substrate by magnetron sputtering; before use, the substrate is ultrasonically cleaned in acetone, alcohol and deionized water, respectively, and dried in a vacuum oven. 8. A method for preparing the anti-corrosion transparent electromagnetic shielding film according to claim 5 or 6, characterized in that it comprises the following steps: preparing a second dielectric layer, a conductive layer and a first dielectric layer in sequence on a substrate by magnetron sputtering; preparing a surface hydrophobic layer on the surface of the first dielectric layer by spin coating; before use, the substrate is ultrasonically cleaned in acetone, alcohol and deionized water, respectively, and dried in a vacuum oven. 9. Use of the anti-corrosion transparent electromagnetic shielding film according to any one of claims 1 to 6 in an electronic touch screen.