High-barrier corrosion-resistant composite film as well as preparation method and application thereof

Abstract

The invention discloses a high-barrier and corrosion-resistant composite film, and belongs to the technical field of flexible films, and a preparation method of the composite film comprises the following specific steps: (1) under a vacuum condition, depositing a metal oxide film on a substrate through a magnetic filter cathode vacuum arc technology; and (2) grafting a liquid-like molecular brush on the metal oxide thin film. By preparing the composite film structure combining the flexible metal oxide film and the liquid-like molecular brush, the corrosion of water and oxygen in the environment can be effectively isolated, and the corrosion resistance can be realized, so that the service life of the device is remarkably prolonged, and the requirements of OLED packaging are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible films, and in particular relates to a high-barrier, corrosion-resistant composite film and a preparation method and application thereof. Background Art

[0002] Organic light-emitting diode (OLED) display technology is a crucial foundation for the general-purpose chip technology that powers the next-generation information industry. The OLED industry has gradually become a strategic frontier for global academia and industry, and a key focus of technological development strategies. With the explosive growth of OLED flexible display technology, the reliability requirements for flexible electronic devices are becoming increasingly stringent. Device stability in air is a major bottleneck restricting OLED development.

[0003] OLED devices are susceptible to aging due to water vapor and oxygen, with bubbles appearing in the electrode area and black spots in the light-emitting area, resulting in a decrease in their service life and luminous stability. To effectively prevent the failure of OLED devices, it is necessary to isolate water vapor and oxygen through device packaging, and to avoid the influence of dust particles during the packaging process. Thin film encapsulation (TFE) technology is an effective means to extend the service life of flexible OLEDs. Among them, flexible metal oxide films (Al2O3, ZnO, ZrO2, MgO and TiO2, etc.) have attracted widespread attention due to their excellent properties and have broad application prospects in flexible electronics, flexible packaging and other fields. However, in addition to water and oxygen in the air, the organic light-emitting materials of OLED devices are also very sensitive to environmental factors such as organic solvents and are easily corroded and degraded. However, traditional oxide films cannot meet the requirements of high barrier and corrosion resistance.

[0004] Therefore, it is an urgent problem for those skilled in the art to provide a high-barrier, corrosion-resistant composite film and a preparation method thereof. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a high-barrier, corrosion-resistant composite film and a preparation method and application thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a high-barrier, corrosion-resistant composite film comprises the following specific steps:

[0008] (1) Deposition of metal oxide thin films on substrates using magnetic filtered cathode vacuum arc technology under vacuum conditions;

[0009] (2) Grafting a liquid molecular brush onto the metal oxide film.

[0010] The present invention prepares a high-barrier flexible metal oxide film through magnetic filtration cathode vacuum arc technology, and grafts liquid molecular brushes on the surface. The obtained composite film has the effects of high barrier and acid, alkali and salt corrosion resistance in packaging applications.

[0011] Preferably, the thickness of the liquid-like molecular brush is 2-10 nm, and the thickness of the metal oxide film is 80-100 nm.

[0012] Preferably, the metal oxide film in step (1) is any one of Al2O3, ZrO2, TiO2, HfO2, MgO and ZnO films.

[0013] Preferably, the vacuum condition in step (1) is 1-3×10 -3 Pa.

[0014] Preferably, in the magnetic filtered cathode vacuum arc technology in step (1), the arc current of the metal target is 30-70A, the flow rate of O2 is 6-50sccm, the deposition time is 20-60min, and the negative bias voltage is 1-7kV.

[0015] Currently, research on encapsulation film deposition methods has largely focused on ALD technology. While ALD can form uniform films, its low deposition energy makes it difficult to achieve high film density. The deposition process requires repeated gas purges, resulting in slow deposition rates. Furthermore, residual hydrogen can negatively impact OLEDs and thin-film transistors. Magnetic filtered cathode vacuum arc technology, on the other hand, offers advantages such as fast deposition, low deposition temperatures, high film density, and the absence of hydrogen during deposition. Therefore, the present invention utilizes this technology to deposit multilayer composite thin films. This technology effectively isolates the film from environmental corrosion, reduces chemical degradation of organic materials, and significantly extends the device's lifespan.

[0016] Preferably, the liquid-like molecular brush in step (2) is dimethyldichlorosilane.

[0017] Preferably, the grafting in step (2) is performed by chemical vapor deposition.

[0018] Preferably, the chemical vapor deposition method in step (2) is carried out under the following conditions: in a closed environment, the metal oxide film reacts with the liquid-like molecular brush at room temperature for 1-20 minutes.

[0019] Preferably, the chemical vapor deposition method further comprises heating the obtained composite film at 50-90° C. for 5-60 minutes after the grafting is completed.

[0020] Liquid molecular brushes are a type of polymer material with a special structure. Their core feature is that a linear polymer chain with a low glass transition temperature is grafted onto the surface of a solid substrate through a covalent bond at one end, while the other end can rotate freely, forming a surface with liquid-like properties. However, the grafted coating in existing technologies does not have water and oxygen barrier properties, or the water barrier performance is only 10 -3 g / m 2 .d, cannot meet the needs of OLED packaging. The present invention forms a tight physical barrier through high-density polymer side chain grafting, which can effectively prevent corrosive substances such as acids, alkalis and salts from contacting the substrate material, and by grafting liquid molecular brushes on the surface of the flexible metal oxide film to construct a new composite film structure, a multifunctional film with corrosion resistance and high barrier is developed, which effectively isolates the erosion of the external environment and reduces the chemical degradation of organic materials, thereby significantly extending the service life of the device and meeting the needs of OLED packaging (10 -6 g / m 2 .d).

[0021] A high-barrier, corrosion-resistant composite film is obtained by the preparation method described above.

[0022] The application of a high-barrier, corrosion-resistant composite film obtained by the preparation method described above in OLED packaging.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention prepares a composite film structure combining a flexible metal oxide film and a liquid-like molecular brush, which can not only effectively isolate the erosion of water and oxygen in the environment, but also be corrosion-resistant, thereby significantly extending the service life of the device and meeting the needs of OLED packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 is a structural diagram of the composite film of the present invention;

[0027] Figure 2 Surface morphology of the TiO2 film and the composite film of the TiO2 film and the liquid-like molecular brush in Example 1 of the present invention;

[0028] Figure 3Graphs showing the transmittance of the substrate, TiO2 film, and the composite film of the TiO2 film and liquid-like molecular brush in Example 1 of the present invention;

[0029] Figure 4 This is a histogram of the sliding angle of the composite film in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figure 1 The present invention provides a high-barrier, corrosion-resistant composite film, comprising an OLED device substrate 1, a metal oxide film 2 on the substrate 1, and a liquid-like molecular brush layer grafted onto the metal oxide film 2;

[0033] The preparation method of the composite film comprises the following specific steps:

[0034] (1) Using a magnetic filtered cathode vacuum arc device, a Ti metal target was installed at the arc head; then the OLED device substrate (PEN) was placed in a vacuum chamber and the vacuum was pumped to 3×10 -3 Pa, argon gas was introduced at 6 sccm;

[0035] (2) Under vacuum conditions, the arc head power supply is turned on, and the cathode target is mechanically triggered to generate arc discharge to form a metal plasma. The arc current is 70A, and the cathode arc discharge is 3 minutes to remove pollutants on the surface of the target. Then, 10 sccm of O2 is introduced. O2 is ionized under the action of the plasma to form O ions, and a TiO2 film is deposited on the OLED device substrate. The deposition time is 30 minutes and the negative bias voltage is 3kV. After completion, the arc head discharge is terminated, and the sample is taken out to obtain a TiO2 film with a thickness of 100 nm.

[0036] (3) placing the sample obtained in step (2) in a sealed container containing 0.1 mmol of dimethyldichlorosilane, reacting for 5 minutes to complete the grafting of the liquid-like molecular brush, and then heating it in an oven at 50°C for 30 minutes to remove unreacted molecules, thereby obtaining a high-barrier, corrosion-resistant composite film, wherein the thickness of the grafted molecular brush is 3 nm and the total thickness of the composite film is 103 nm;

[0037] in, Figure 2Surface morphology of the TiO2 film and the composite film of the TiO2 film and the liquid-like molecular brush in this embodiment. As can be seen from the figure, there are no large particles on the surface of the two films, and the roughness is low;

[0038] Figure 3 Graphs showing the transmittance of the substrate, TiO2 film, and the composite film of the TiO2 film and liquid-like molecular brush in this embodiment show that the average transmittance of all films in the visible light range is above 85%.

[0039] Figure 4 This is a bar graph of the sliding angle of the composite film in this embodiment. It can be seen from the figure that acid, alkali and salt solutions can easily slide off the surface of the composite film, but will not slide off the surface of the composite film. This proves that the composite film after the liquid-like molecular brush grafting can be used in related fields of corrosion resistance and provides a basis for anti-fouling.

[0040] Example 2

[0041] like Figure 1 The present invention provides a high-barrier, corrosion-resistant composite film, comprising an OLED device substrate 1, a metal oxide film 2 on the substrate 1, and a liquid-like molecular brush layer grafted onto the metal oxide film 2;

[0042] The preparation method of the composite film comprises the following specific steps:

[0043] (1) Using a magnetic filtered cathode vacuum arc device, a Ti metal target was installed at the arc head; then the OLED device substrate (PEN) was placed in a vacuum chamber and the vacuum was pumped to 2×10 -3 Pa, argon gas was introduced at 10 sccm;

[0044] (2) Under vacuum conditions, the arc head power supply is turned on, and the cathode target is mechanically triggered to generate arc discharge to form a metal plasma. The arc current is 70A and the cathode arc discharge is performed for 5 minutes to remove pollutants on the target surface. Then, 15 sccm of O2 is introduced. O2 is ionized under the action of the plasma to form O ions, and a TiO2 film is deposited on the OLED device substrate. The deposition time is 24 minutes and the negative bias voltage is 5 kV. After completion, the arc head discharge is terminated and the sample is taken out to obtain a TiO2 film with a thickness of 80 nm.

[0045] (3) The sample obtained in step (2) was placed in a sealed container containing 0.3 mmol of dimethyldichlorosilane, and the grafting of the liquid-like molecular brush was completed after the reaction for 10 minutes. The sample was then placed in an oven and heated at 60°C for 20 minutes to remove unreacted molecules, thereby obtaining a high-barrier, corrosion-resistant composite film, wherein the thickness of the grafted molecular brush was 7 nm and the total thickness of the composite film was 87 nm.

[0046] Water vapor transmission rate tests were conducted on the composite films in Examples 1-2 and the TiO2 film in Example 1. The results are shown in Table 1.

[0047] Table 1 Water vapor transmission rate results of TiO2 thin films and composite films

[0048] sample <![CDATA[Water vapor transmission rate (g / m 2 / day)]]> <![CDATA[TiO2 thin film]]> <![CDATA[4.9×10 -6 ]]> Composite film (Example 1) <![CDATA[3.8×10 -6 ]]> Composite film (Example 2) <![CDATA[5.7×10 -6 ]]> PEN substrate 1.94 Liquid-like molecular brushes grafted onto PEN substrate 1.21

[0049] As can be seen from the table, the water vapor permeability of the PEN substrate is only 1.94g / m 2 / day, the water vapor transmission rate of TiO2 film after deposition is 4.9×10 -6 g / m 2 / day, with high barrier properties, and the water vapor permeability of the composite film of TiO2 film and liquid-like molecular brushes is 3.8×10 -6 g / m 2 / day, the barrier effect is slightly improved, the thickness of the metal oxide film in Example 2 is reduced, and the water vapor transmission rate is increased.

[0050] The various embodiments are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0051] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-barrier, corrosion-resistant composite film, characterized in that: The specific steps include: (1) Deposition of metal oxide thin films on substrates using magnetic filtered cathode vacuum arc technology under vacuum conditions; (2) Grafting a liquid molecular brush onto the metal oxide film.

2. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 1, characterized in that: The thickness of the liquid-like molecular brush is 2-10 nm, and the thickness of the metal oxide film is 80-100 nm.

3. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 1, characterized in that: The metal oxide film in step (1) is any one of Al2O3, ZrO2, TiO2, HfO2, MgO and ZnO films.

4. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 1, characterized in that: The vacuum condition in step (1) is 1-3×10 -3 Pa.

5. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 1, characterized in that: In the magnetic filtered cathode vacuum arc technology described in step (1), the arc current of the metal target is 30-70A, the flow rate of O2 is 6-50sccm, the deposition time is 20-60min, and the negative bias voltage is 1-7kV.

6. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 1, characterized in that: The liquid-like molecular brush in step (2) is dimethyldichlorosilane.

7. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 1, characterized in that: The grafting in step (2) is carried out by chemical vapor deposition; The chemical vapor deposition method is carried out under the following conditions: in a closed environment, the metal oxide film and the liquid-like molecular brush react at room temperature for 1-20 minutes.

8. The method for preparing a high-barrier, corrosion-resistant composite film according to claim 7, characterized in that: The chemical vapor deposition method further includes heating the obtained composite film at 50-90° C. for 5-60 minutes after the grafting is completed.

9. A high-barrier, corrosion-resistant composite film obtained by the preparation method according to any one of claims 1 to 8.

10. Use of a high-barrier, corrosion-resistant composite film obtained by the preparation method according to any one of claims 1 to 8 in OLED packaging.

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