Preparation method of graphene-amorphous hexagonal boron nitride composite film with high water and oxygen barrier property

Abstract

The invention discloses a preparation method of a graphene-amorphous hexagonal boron nitride water-oxygen barrier film with high water-oxygen barrier performance. According to the method, a transparent flexible substrate is used as a supporting substrate, a lamination process is adopted to transfer the graphene-hexagonal boron nitride composite film, and transfer process conditions are continuously optimized based on the design of transfer medium components and structures. Meanwhile, by utilizing the advantages of high barrier, high light transmission, flexibility and the like of hexagonal boron nitride and graphene, a graphene-amorphous hexagonal boron nitride composite structure is constructed to improve the water and oxygen barrier property, and conformal fitting between the graphene-amorphous hexagonal boron nitride composite structure film and a target polymer substrate (carrier) and between film layers is realized; the large-size high-barrier graphene-amorphous hexagonal boron nitride water-oxygen barrier film is prepared by the steps of preparing a graphene-amorphous hexagonal boron nitride film, effectively avoiding damage generated in a transfer process, enhancing interlayer coupling of the graphene-amorphous hexagonal boron nitride film, increasing energy barriers of migration and permeation of water and oxygen molecules among the film layers, improving barrier performance and preparing the large-size high-barrier graphene-amorphous hexagonal boron nitride water-oxygen barrier film.

Description

Technical Field

[0001] The invention belongs to the field of two-dimensional materials, and in particular relates to a method for preparing a graphene-amorphous hexagonal boron nitride composite film with high water and oxygen barrier performance. Background Art

[0002] Graphene and hexagonal boron nitride films prepared by chemical vapor deposition (CVD) can be used as packaging materials for organic optoelectronic devices due to their unique structure, excellent mechanical properties, high transparency and other advantages. The lattice difference between hexagonal boron nitride and graphene surfaces is only about 1.8%, and both can effectively protect the organic functional layer and electrodes of the device and improve the device life. The preparation of graphene films by chemical vapor deposition has gradually matured, but it is still rare to uniformly grow amorphous hexagonal boron nitride on the surface of graphene. If the graphene-amorphous hexagonal boron nitride composite film grown by CVD is applied to the field of low-dimensional composite material preparation technology, it still needs to be transferred to the target substrate and the integrity of the graphene-amorphous hexagonal boron nitride film and the functionality of the composite material should be maintained; the transfer technology directly affects the quality of the graphene-amorphous hexagonal boron nitride composite film after transfer, as well as the subsequent characterization and application. The interface cleanliness and fit between the graphene-amorphous hexagonal boron nitride composite film and other components in the composite material during the transfer will also directly affect the barrier properties of the composite film. At present, the technology of water and oxygen barrier film with graphene-amorphous hexagonal boron nitride composite structure is still in its infancy and needs to be further studied.

[0003] The performance of the graphene-amorphous hexagonal boron nitride composite structure barrier film is not only related to the integrity of the graphene-amorphous hexagonal boron nitride composite structure, but also closely related to the interlayer spacing of the graphene-amorphous hexagonal boron nitride composite structure, the spacing between the graphene-amorphous hexagonal boron nitride composite structure and the substrate, and the interface cleanliness. In the process of transferring the graphene-amorphous hexagonal boron nitride composite structure from the growth substrate to the functional substrate to prepare the barrier film, the traditional preparation process involves transfer methods such as polymer transfer medium assisted transfer and thermal release tape assisted transfer. These methods will have many problems in large-scale production. For example: polymer assisted transfer transfers the graphene-amorphous hexagonal boron nitride composite structure to the target substrate relatively intact, but the polymer transfer medium is on the surface of the graphene-amorphous hexagonal boron nitride composite structure film, and the removal process will cause damage to the graphene-amorphous hexagonal boron nitride composite structure film and residues of the transfer medium. On the other hand, the separation principle of the thermal release tape is that the heat-expandable microspheres in the adhesive layer expand when heated, squeeze out of the adhesive layer surface, reduce the contact area between the adhesive layer and the sample, and thus reduce the bonding force. However, when peeling, the microspheres expand when heated, and the stress generated will cause the bonded graphene-amorphous hexagonal boron nitride composite structure film to wrinkle and break, and the quality will decrease; and there will still be a small area of ​​adhesive layer remaining that cannot be completely removed. All of these will cause the barrier performance of the graphene-amorphous hexagonal boron nitride composite film to decrease.

[0004] Therefore, a method for preparing a graphene-amorphous hexagonal boron nitride composite film is urgently needed: when the graphene-amorphous hexagonal boron nitride composite structure is used as a component of the composite film, the polymer that assists in the transfer can be retained as the functional layer therein, avoiding the problem of hexagonal boron nitride damage and glue residue caused by glue removal. At the same time, through special treatment, the distance between the hexagonal boron nitride and the functional layer is reduced, and the interface cleanliness is increased, thereby effectively improving the water and oxygen barrier performance. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for preparing a graphene-amorphous hexagonal boron nitride water and oxygen barrier film.

[0006] The method for preparing the graphene-amorphous hexagonal boron nitride water and oxygen barrier film provided by the present invention comprises the following steps:

[0007] 1) spin coating an organic glue layer on the surface of a graphene-amorphous hexagonal boron nitride composite structure film grown on a metal substrate to obtain an organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / metal substrate composite;

[0008] 2) adhering a polymer film / polyacrylic acid layer composite film on the surface of the organic glue layer so that the organic glue layer contacts the polyacrylic acid layer; removing the metal substrate to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film;

[0009] 3) Spin coating a two-dimensional material layer on the surface of the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film in step 2) to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer;

[0010] 4) The polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer described in step 3) is laminated with the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film described in step 2) to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer / graphene-amorphous hexagonal boron nitride composite structure film / organic glue layer / polyacrylic acid layer / polymer film, i.e., the graphene-amorphous hexagonal boron nitride water and oxygen barrier film.

[0011] In step 1) of the above method, the metal substrate is one of Cu, Fe, Ni or an alloy thereof, and the graphene-amorphous hexagonal boron nitride composite film has a thickness of 0.5 to 500 nm.

[0012] In step 1) of the above method, the organic glue layer is in direct contact with the amorphous hexagonal boron nitride film in the graphene-amorphous hexagonal boron nitride composite film; the thickness of the organic glue layer is 500nm to 10μm; preferably, the thickness is 500nm to 5μm.

[0013] In step 1) of the above method, in the graphene-amorphous hexagonal boron nitride composite structure film grown on the metal substrate, the graphene is directly connected to the metal substrate, the amorphous boron nitride is grown on the surface of the graphene, and the organic glue layer is in contact with the amorphous hexagonal boron nitride.

[0014] In step 1) of the above method, the organic adhesive layer includes one or more of ethylene-vinyl acetate copolymer (EVA), polyvinylidene fluoride (PVDF), polystyrene (PS), and polyolefin elastomer (POE); preferably, the organic adhesive layer is selected from ethylene-vinyl acetate copolymer.

[0015] In step 1) of the above method, the graphene-amorphous hexagonal boron nitride composite structure film grown on the metal substrate is prepared by chemical vapor deposition (CVD technology).

[0016] The preparation of a large-sized graphene-amorphous hexagonal boron nitride composite structure with a large area and low defect density is a prerequisite for preparing a large-sized graphene barrier film according to the present invention.

[0017] The specific preparation method comprises the following steps: using methane and hydrogen to grow graphene (such as single-layer graphene) on a metal substrate (such as copper foil) in a tube furnace; then using boron ammonia (NH 3 BH 3 ) complex as nitrogen source and boron source, and amorphous hexagonal boron nitride is grown under argon and hydrogen conditions, and finally a graphene-amorphous hexagonal boron nitride composite structure film is grown on a metal substrate.

[0018] In step 2) of the above method, the polymer film is selected from one or more of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyimide (PI), polytetrafluoroethylene (PTFE), polypropylene (BOPP), polyethylene (PE), and polyolefin elastomer (POE); the thickness of the polymer film may be 50 to 150 μm.

[0019] In step 2) of the above method, the monomer forming the polyacrylic acid may be acrylic acid and / or acrylic acid containing a modified group; the modified group contains one or more of the functional groups such as methyl, ethyl, fluorine, chlorine, and amino. The thickness of the polyacrylic acid layer may be 1 to 50 μm, and the peel strength may be 1 to 200 g / 25 mm.

[0020] In step 2) of the above method, the temperature of the adhesive polymer film / polyacrylic acid layer composite film is 40-100° C., and the heating time of the adhesive is 1-180 min.

[0021] In step 2) of the above method, the metal substrate is removed by etching or electrochemical bubbling.

[0022] Preferably, when the metal substrate is removed by etching, the etching solution is one or more solutions of cupric chloride, ferric chloride, potassium ferrocyanide, hydrochloric acid or nitric acid, and the concentration of the etching solution is 0.5 mol / L to 2.0 mol / L; more preferably, the metal substrate is removed by ferric chloride etching, and the concentration of the ferric chloride etching solution is 0.5 mol / L to 2.0 mol / L.

[0023] Preferably, when the metal substrate is removed by electrochemical bubbling method, platinum or graphite is used as the anode, the metal substrate is used as the cathode, the electrolyte is a solution of one or more of sodium hydroxide, potassium hydroxide, sodium nitrate, potassium nitrate, and ammonium nitrate, and the concentration of the electrolyte is 0.5 mol / L to 2.0 mol / L.

[0024] In step 3) of the above method, the two-dimensional material layer is selected from one or more of hexagonal boron nitride, hydroxy boron nitride, and molybdenum disulfide; preferably, hydroxy boron nitride.

[0025] In step 3) of the above method, the two-dimensional material layer is in direct contact with the graphene, and the thickness of the two-dimensional material layer is 0.5 nm to 10 μm, preferably 1 to 800 nm.

[0026] In step 4) of the above method, the temperature of laminating the polymer film / polyacrylic acid layer / organic adhesive layer / graphene-amorphous hexagonal boron nitride composite structure / two-dimensional material layer to the polymer film / polyacrylic acid layer / organic adhesive layer / graphene-amorphous hexagonal boron nitride composite structure thin film is 40-100°C, and the heating time of the laminating is 1-180 min.

[0027] In the above method, the graphene-amorphous hexagonal boron nitride composite structure film and the graphene-amorphous hexagonal boron nitride composite structure film have the same structure. It is only to facilitate understanding of the positional relationship between the graphene layer or the amorphous hexagonal boron nitride layer and other layers (organic glue layer or two-dimensional material layer) in the above film, and a more appropriate expression is selected. For example, the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer / graphene-amorphous hexagonal boron nitride composite structure film / organic glue layer / polyacrylic acid layer / polymer film prepared above, wherein the expression of amorphous hexagonal boron nitride-graphene composite structure film is adopted, which can facilitate understanding that amorphous hexagonal boron nitride is in contact with the organic glue layer, and the expression of graphene-amorphous hexagonal boron nitride composite structure film is adopted, which can facilitate understanding that graphene is in contact with the two-dimensional material layer.

[0028] The polymer film / polyacrylic acid layer / organic adhesive layer / graphene-amorphous hexagonal boron nitride composite structure film / two-dimensional material layer / graphene-amorphous hexagonal boron nitride composite structure film / organic adhesive layer / polyacrylic acid layer / polymer film prepared by the above method also belongs to the protection scope of the present invention. In the composite film, both sides of the two-dimensional material layer are in direct contact with graphene.

[0029] The present invention grows a single layer of graphene on a metal substrate by chemical vapor deposition, and grows a layer of amorphous hexagonal boron nitride on the graphene surface, thereby modifying the graphene surface and obtaining a graphene-amorphous hexagonal boron nitride composite structure. Compared with the artificially bonded graphene and hexagonal boron nitride films, the step-by-step grown graphene-amorphous hexagonal boron nitride composite structure is more tightly bonded, without bubbles, wrinkles, impurities and damage, and greatly improves the water and oxygen barrier performance of the barrier film. In addition, hexagonal boron nitride can be perfectly bonded to the organic adhesive layer, and it is not easy to produce gaps, thereby ensuring the integrity of the graphene-amorphous hexagonal boron nitride composite structure. The characteristics of water molecules on the hexagonal boron nitride surface, such as strong friction, slow down the slip of water molecules on the boron nitride surface. At the same time, the hydrogen bonding between the two-dimensional material and the water molecules further improves the barrier properties of the water molecules. The present invention is expected to replace the traditional graphene barrier film to achieve higher barrier performance and promote the further development of water and oxygen barrier films.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The preparation method of the present invention utilizes an organic adhesive layer to isolate the direct contact between the graphene-amorphous hexagonal boron nitride composite structure and the polymer film / polyacrylic acid layer composite layer. The organic adhesive layer is retained as a functional layer to avoid damage to the graphene-amorphous hexagonal boron nitride composite structure caused by stress when the organic adhesive layer is removed. The preferred organic adhesive has a strong interaction with the surface of the graphene-amorphous hexagonal boron nitride composite structure, so that the graphene-amorphous hexagonal boron nitride composite structure film is firmly fixed on the polymer film, which can improve the barrier performance of the graphene-amorphous hexagonal boron nitride composite film. At the same time, in view of the problem of weak supporting force of the organic adhesive layer, the use of a polymer film / polyacrylic acid layer can improve the supporting strength of the organic adhesive layer. The operating requirements for the staff during the transfer process of the graphene-amorphous hexagonal boron nitride composite structure film are reduced, the transfer efficiency is improved, and the graphene-amorphous hexagonal boron nitride composite structure film after transfer has a complete structure and excellent barrier performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0033] Figure 1 The present invention is a schematic diagram of the process flow of the method for preparing the graphene-amorphous hexagonal boron nitride water and oxygen barrier film.

[0034] Figure 2 For example 1, the 2 Optical microscope image of hexagonal boron nitride substrate.

[0035] Figure 3 For example 1, the 2Raman spectrum of hexagonal boron nitride substrate.

[0036] Figure 4 This is a graph showing the water permeability test results of the graphene-amorphous hexagonal boron nitride water and oxygen barrier film prepared in Example 1.

[0037] Figure 5 This is a graph showing the water permeability test results of the graphene barrier membrane in the comparative example. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0039] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0040] The step numbers S1, S2, S3, S4, S5 and S6 described in this article are for the convenience of distinguishing different steps, and are not intended to limit the order and continuity of the steps, that is, other auxiliary steps such as cleaning, drying, etc. may be included between any of the steps.

[0041] like Figure 1As shown, the preparation method of the graphene-amorphous hexagonal boron nitride water and oxygen barrier film of the present invention comprises: S1, directly growing a graphene-amorphous hexagonal boron nitride composite structure film on a metal substrate by CVD technology; S2, spin coating an organic glue layer on the surface of the graphene-amorphous hexagonal boron nitride composite structure film directly grown on the metal substrate to obtain an organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / metal substrate composite; S3, adhering a polymer film / polyacrylic acid layer composite film on the surface of the organic glue layer, wherein the polyacrylic acid layer is in contact with the organic glue layer; S4, removing the metal substrate by etching to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film; S5, polymer film / The surface of the polyacrylic acid layer / organic adhesive layer / amorphous hexagonal boron nitride-graphene composite structure film is spin-coated with a two-dimensional material layer to obtain a polymer film / polyacrylic acid layer / organic adhesive layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer composite; S6, laminating the polymer film / polyacrylic acid layer / organic adhesive layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer to the side of the polymer film / polyacrylic acid layer / organic adhesive layer / amorphous hexagonal boron nitride-graphene composite structure film to obtain a polymer film / polyacrylic acid layer / organic adhesive layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer / graphene-amorphous hexagonal boron nitride composite structure film / organic adhesive layer / polyacrylic acid layer / polymer film composite.

[0042] In step S1, a graphene-amorphous hexagonal boron nitride composite structure film is grown on a metal substrate by chemical vapor deposition. The metal substrate is a metal foil of Cu, Fe, Ni or its alloy that catalyzes the growth of graphene and hexagonal boron nitride. The pre-transferred graphene film is 1 to 3 layers, and those skilled in the art can select any number of layers according to actual needs, such as 2 layers, 3 layers, etc. The thickness of amorphous hexagonal boron nitride is 0.5 to 500 nm, and those skilled in the art can select any thickness according to actual needs, such as 3 nm, 5 nm, etc.

[0043] In step S2, a uniform organic adhesive layer is formed on the graphene-amorphous hexagonal boron nitride composite structure film on the metal substrate. First, the organic polymer is dissolved in an organic solvent to form a solution, and then the organic polymer solution is coated on the upper surface of the graphene-amorphous hexagonal boron nitride composite structure film. The organic adhesive layer / amorphous hexagonal boron nitride-graphene composite structure film / metal substrate composite is formed after the solvent is evaporated by heating on a hot plate. Any appropriate coating method can be selected, such as scraping, spin coating, spraying, etc. The organic adhesive layer is composed of one or more of ethylene-vinyl acetate, polyvinylidene fluoride, polystyrene, and polyolefin elastomer. According to the selected organic polymer and coating method, an appropriate solvent and solution concentration are selected. The specific parameters are not limited here. Those skilled in the art can understand that the purpose of configuring the organic polymer solution is to form an organic adhesive layer, as long as the organic polymer solution can achieve the above purpose. The thickness of the organic adhesive layer is 500nm to 10μm. When the thickness of the organic adhesive layer is less than 500nm, the isolation effect of the organic adhesive layer on the polymer film / polyacrylic acid layer support layer cannot reach the best; however, those skilled in the art should understand that as long as an organic adhesive layer is provided between the polymer film / polyacrylic acid layer and the graphene-amorphous hexagonal boron nitride composite structure film, the contamination of the polyacrylic acid layer on the graphene-amorphous hexagonal boron nitride composite structure film can be reduced. The limitation of the thickness to not less than 500nm is only to reduce the contamination to the ideal standard, and is not used to limit the present invention. When the thickness of the organic adhesive layer is greater than 10μm, the thickness of the barrier film will increase and the light transmittance will be reduced. Preferably, the thickness of the organic adhesive layer is 500nm to 5μm.

[0044] More preferably, the organic glue layer can be a composite layer including multiple layers. For example, when two organic glue layers are included, the first organic glue layer is in direct contact with the graphene-amorphous hexagonal boron nitride composite structure film, and the second organic glue layer is adhered to the surface of the first organic glue layer away from the graphene-amorphous hexagonal boron nitride composite structure film. The first organic glue layer is in direct contact with the graphene-amorphous hexagonal boron nitride composite structure film and fully combined to ensure that the graphene-amorphous hexagonal boron nitride composite structure film will not be damaged during transfer. If the thickness of the first organic glue layer is too thin, the bonding force is insufficient, and the graphene-amorphous hexagonal boron nitride composite structure film cannot be completely transferred. If it is too thick, it will affect the thickness and light transmittance of the overall composite film. Preferably, the thickness of the first organic glue layer is 500nm to 10μm. Preferably, the first organic glue layer selects a material with a large force on the graphene-amorphous hexagonal boron nitride composite structure film to increase the bonding between the graphene-amorphous hexagonal boron nitride composite structure film and the polymer film. For example, the first organic glue layer may be, but is not limited to, one or more selected from ethylene vinyl acetate, polyvinylidene fluoride, polystyrene, and polyolefin elastomer.

[0045] The organic adhesive layer includes a single layer or multiple layers, preferably a single layer, which is not intended to limit the present invention. According to the above introduction, the skilled person in the art should know that when the organic adhesive layer is a single layer, the graphene-amorphous hexagonal boron nitride composite structure film and the polymer film can be tightly combined, and the graphene-amorphous hexagonal boron nitride composite structure film remains intact and clean during the transfer process.

[0046] In step S3, a polymer film / polyacrylic acid layer composite film is adhered to the surface of the organic adhesive layer. The polymer film / polyacrylic acid layer composite film has stronger mechanical properties than the organic adhesive layer, which can reduce the operating requirements for workers during the transfer of the graphene-amorphous hexagonal boron nitride composite structure film, and can achieve the bonding of the graphene-amorphous hexagonal boron nitride composite structure film and the polymer film / polyacrylic acid layer composite film target substrate, improve the transfer efficiency, and make the transfer of the graphene-amorphous hexagonal boron nitride composite structure film easier to achieve. The organic adhesive layer and the polymer film / polyacrylic acid layer composite film are both part of the barrier film, and the conformal bonding between the two helps to improve the performance of the barrier film.

[0047] In this step, the acrylic acid used in the polyacrylic acid layer may be a modified group containing one or more of the functional groups such as methyl, ethyl, fluorine, chlorine, and amino. Those skilled in the art can select a suitable specific type of acrylic acid according to the performance of the polyacrylic acid to be used. The thickness of the polyacrylic acid layer is 1 to 50 μm, and the peel strength is 1 to 200 g / 25 mm; if the peel strength of the polyacrylic acid layer is too high, the mechanical force used to separate the polyacrylic acid from the release film will be too large, resulting in deformation of the polymer film / polyacrylic acid film, affecting the bonding with the organic adhesive layer / graphene-amorphous hexagonal boron nitride composite structure film / metal substrate composite film. The stress generated by the organic adhesive layer is released to the graphene-amorphous hexagonal boron nitride composite structure film. If the peel strength of the polyacrylic acid layer is too low, the bonding force is weak, and the organic adhesive layer / graphene-amorphous hexagonal boron nitride composite structure film / metal substrate cannot be bonded to the polymer film / polyacrylic acid layer composite film. Those skilled in the art can select a polyacrylic acid layer of suitable thickness and peel strength according to actual needs. For example, but not limited to, the thickness of the polyacrylic acid layer is 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, etc.; the peel strength is 1g / 25mm, 10g / 25mm, 20g / 25mm, 30g / 25mm, 50g / 25mm, 70g / 25mm, 90g / 25mm, 110g / 25mm, 130g / 25mm, 150g / 25mm, 170g / 25mm, 200g / 25mm, etc. The polymer film is composed of one or more of PEN, PET, PI, PTFE, BOPP, PE, and POE. The above polymers have good strength and can play a supporting role to prevent the polyacrylic acid layer from deforming; the thickness of the polymer film is 50 to 150 μm. Those skilled in the art can select a suitable polymer film thickness according to actual needs, such as but not limited to 50 μm, 70 μm, 90 μm, 110 μm, 130 μm, 150 μm, etc.

[0048] In step S4, the metal substrate is removed to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film. The metal substrate can be removed by etching or bubbling. When the metal substrate is removed by etching, the etching solution is a solution of one or more of copper chloride, ferric chloride, potassium ferrocyanide, hydrochloric acid or nitric acid, and the etching solution concentration is 0.5 mol / L to 2.0 mol / L. When the metal substrate is removed by bubbling, platinum or graphite can be used as the anode, the metal substrate can be used as the cathode, and the electrolyte can be a solution of one or more of sodium hydroxide, potassium hydroxide, sodium nitrate, potassium nitrate, and ammonium nitrate, and the electrolyte concentration is 0.5 mol / L to 2.0 mol / L. After the metal substrate is completely etched or separated by bubbling, the composite film is placed in deionized water for cleaning, the residual etching solution or electrolyte is removed, and the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film is obtained after drying.

[0049] In step S5, a uniform two-dimensional material layer is formed on the surface of the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film. The two-dimensional material is dispersed in an organic solvent to form a dispersion, and then the two-dimensional material dispersion is applied to the lower surface of the graphene-amorphous hexagonal boron nitride composite structure film (i.e., the surface of the graphene layer), and the solvent is evaporated by heating on a hot plate to form a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer composite. The coating method can also be selected from any appropriate method, such as scraping, spin coating, spraying, etc. The two-dimensional material layer is selected from one or more of hexagonal boron nitride, hydroxy boron nitride, molybdenum disulfide, etc. According to the selected two-dimensional material and coating method, an appropriate solvent and solution concentration are selected. The specific parameters are not limited here. Those skilled in the art can understand that the purpose of preparing the two-dimensional material dispersion is to form a two-dimensional material layer, as long as the two-dimensional material dispersion can achieve the above purpose. The thickness of the two-dimensional material layer is 0.5nm to 10μm.

[0050] In step S6, the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer is laminated to the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer / graphene-amorphous hexagonal boron nitride composite structure film / organic glue layer / polyacrylic acid layer / polymer film composite. In addition to the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film, the target substrate can also be selected from any appropriate substrate, such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). The laminating rolling temperature is 40 to 150° C., and the heating time is 1 to 180 min.

[0051] The present invention is further described below by specific examples. However, these examples are merely exemplary and do not constitute any limitation to the protection scope of the present invention.

[0052] Example 1

[0053] A single-layer graphene-amorphous hexagonal boron nitride composite structure film (thickness 10 nm) grown on a 10 cm×10 cm copper substrate was selected. EVA (Aladdin, cas: 24937-78-8, VA content 40 wt.%) was dissolved in toluene, the mass fraction of EVA was 4%, and the EVA solution was spin-coated on the surface of the graphene-amorphous hexagonal boron nitride composite structure film at a speed of 2000 rpm (EVA was in direct contact with amorphous hexagonal boron nitride), and cured at 80° C. for 15 min to obtain an EVA / amorphous hexagonal boron nitride-graphene composite structure film / copper substrate composite, wherein the thickness of the EVA layer was 10 μm.

[0054] The EVA / amorphous hexagonal boron nitride-graphene composite structure film / copper substrate composite was roll-laminated to a PEN / polyacrylic acid layer composite (PEN film thickness 50 μm, polyacrylic acid layer peel strength 160 g / 25 mm), and the EVA was brought into contact with the polyacrylic acid layer to obtain a PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film / copper substrate composite.

[0055] The PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film / copper substrate composite body was immersed in a ferric chloride etching solution (concentration 1.0 mol / L). After the metal foil was completely etched, it was respectively placed in 1M dilute hydrochloric acid and deionized water for cleaning to remove the residual etching solution. The composite film PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film was placed in a vacuum drying oven at 60°C and dried for 8 hours. Hydroxyboron nitride was spin-coated on the lower surface (graphene side) of the graphene-amorphous hexagonal boron nitride composite structure film and dried on a hot stage at 80°C for 30 minutes to obtain a PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film / hydroxyboron nitride layer, wherein the thickness of the hydroxyboron nitride was 2 nm.

[0056] The side of the hydroxyl boron nitride layer is attached to the target substrate PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film, with the target substrate layer facing downward, and the PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film / hydroxyl boron nitride complex is closely attached to the PEN / polyacrylic acid / EVA / amorphous hexagonal boron nitride-graphene composite structure film complex through a roller press (both sides of the hydroxyl boron nitride are in direct contact with the graphene). Then, hot pressing is performed at 80°C for 4 hours to complete the preparation process of the graphene-amorphous hexagonal boron nitride barrier film.

[0057] Comparative Example 1

[0058] A single-layer graphene film grown on a 10cm×10cm copper substrate was directly spin-coated with EVA (the thickness of the EVA layer was 10 μm), and the same PEN film / polyacrylic acid layer composite film as in Example 1 was rolled and laminated onto the EVA / graphene film / copper substrate composite film to form a PEN / polyacrylic acid layer / EVA / graphene film / copper substrate. The composite was immersed in a ferric chloride etching solution, which was the same as in Example 1. After the metal foil was completely etched, it was washed with 1M dilute hydrochloric acid and deionized water, respectively, to remove the residual etching solution, and a PEN / polyacrylic acid layer / EVA / graphene film composite film was obtained. The PEN / polyacrylic acid / EVA / graphene film composite film was placed in a vacuum drying oven at 60°C and dried for 8 hours; hydroxyboron nitride was spin-coated on the surface of the graphene film and dried on a hot plate at 80°C for 30 minutes to obtain a PEN / polyacrylic acid / EVA / graphene film / hydroxyboron nitride layer (the thickness of the hydroxyboron nitride layer was the same as in Example 1), and the side of the hydroxyboron nitride layer was attached to the target substrate PEN / polyacrylic acid / EVA / graphene film, with the target base layer facing downward, and passed through a roller press to closely fit the PEN / polyacrylic acid / EVA / graphene film / hydroxyboron nitride complex with the PEN / polyacrylic acid / EVA / graphene film complex (so that both sides of the hydroxyboron nitride were in direct contact with the graphene). Then, hot pressing was performed at 80°C for 4 hours to complete the preparation process of the graphene barrier film.

[0059] The water vapor permeability test of the barrier films prepared in Example 1 and Comparative Example 1 was conducted by calcium film oxidation method for 30 days. From the measured water vapor permeability, it can be seen that the water barrier performance of the graphene barrier film of Comparative Example 1 is ( Figure 5 ) and Example 1 ( Figure 4 ) results are quite different. This is mainly because the amorphous hexagonal boron nitride grown on the graphene surface further reduces the channels for water molecules to penetrate. At the same time, the polarity of amorphous hexagonal boron nitride will further affect the slip length of water molecules, making it more difficult for water molecules to penetrate. The large amount of hydroxyl groups contained in the two-dimensional material can form hydrogen bonds with water molecules, significantly reducing the permeability of water molecules.

[0060] The present invention has been described in detail above. It will be apparent to those skilled in the art that the present invention may be implemented in a wide range under equivalent parameters, concentrations and conditions without departing from the spirit and scope of the present invention and without the need for unnecessary experimentation. Although the present invention provides specific embodiments, it should be understood that further improvements may be made to the present invention. In short, according to the principles of the present invention, this application intends to include any changes, uses or improvements to the present invention, including changes made by conventional techniques known in the art that depart from the scope disclosed in this application. Applications of some of the basic features may be made within the scope of the following appended claims.

Claims

1. A method for preparing a graphene-amorphous hexagonal boron nitride water and oxygen barrier film, comprising the following steps: 1) spin coating an organic glue layer on the surface of a graphene-amorphous hexagonal boron nitride composite structure film grown on a metal substrate to obtain an organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / metal substrate composite; 2) adhering a polymer film / polyacrylic acid layer composite film on the surface of the organic glue layer so that the organic glue layer contacts the polyacrylic acid layer; removing the metal substrate to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film; 3) Spin coating a two-dimensional material layer on the surface of the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film in step 2) to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer; 4) The polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer described in step 3) is laminated with the polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film described in step 2) to obtain a polymer film / polyacrylic acid layer / organic glue layer / amorphous hexagonal boron nitride-graphene composite structure film / two-dimensional material layer / graphene-amorphous hexagonal boron nitride composite structure film / organic glue layer / polyacrylic acid layer / polymer film, i.e., the graphene-amorphous hexagonal boron nitride water and oxygen barrier film.

2. The preparation method according to claim 1, characterized in that: In the step 1), the metal substrate is one of Cu, Fe, Ni or an alloy thereof; And / or, the graphene-amorphous hexagonal boron nitride composite film has a thickness of 0.5 to 500 nm.

3. The preparation method according to claim 1 or 2, characterized in that: In the step 1), the thickness of the organic glue layer is 500nm to 10μm; And / or, the organic adhesive layer includes one or more of ethylene-vinyl acetate copolymer, polyvinylidene fluoride, polystyrene, and polyolefin elastomer.

4. The preparation method according to any one of claims 1 to 3, characterized in that: In the step 1), the graphene-amorphous hexagonal boron nitride composite structure film grown on the metal substrate is prepared by a chemical vapor deposition method, and the specific preparation method includes the following steps: in a tube furnace, using methane and hydrogen to grow graphene on the metal substrate; then using boron ammonia complex as a nitrogen source and a boron source, growing amorphous hexagonal boron nitride under argon and hydrogen conditions, and finally growing a graphene-amorphous hexagonal boron nitride composite structure film on the metal substrate.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In the step 2), the polymer film is selected from one or more of polyethylene naphthalate, polyethylene terephthalate, polyimide, polytetrafluoroethylene, polypropylene, polyethylene, and polyolefin elastomer; and / or, the polymer film has a thickness of 50 to 150 μm; And / or, the monomers forming the polyacrylic acid are acrylic acid and / or acrylic acid containing a modified group; The modifying group contains one or more of the functional groups such as methyl, ethyl, fluorine, chlorine, amino, etc.; And / or, the polyacrylic acid layer has a thickness of 1 to 50 μm and a peel strength of 1 to 200 g / 25 mm. And / or, the temperature of the adhesive polymer film / polyacrylic acid layer composite film is 40-100° C., and the heating time of the adhesive is 1-180 min.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In the step 2), the metal substrate is removed by etching or electrochemical bubbling.

7. The preparation method according to claim 6, characterized in that: When the metal substrate is removed by etching, the etching solution is one or more solutions of cupric chloride, ferric chloride, potassium ferrocyanide, hydrochloric acid or nitric acid, and the concentration of the etching solution is 0.5 mol / L to 2.0 mol / L; And / or, when the metal substrate is removed by electrochemical bubbling method, platinum or graphite is used as the anode, the metal substrate is used as the cathode, the electrolyte is a solution of one or more of sodium hydroxide, potassium hydroxide, sodium nitrate, potassium nitrate, and ammonium nitrate, and the concentration of the electrolyte is 0.5 mol / L to 2.0 mol / L.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In the step 3), the two-dimensional material layer is selected from one or more of hexagonal boron nitride, hydroxyboron nitride, and molybdenum disulfide; And / or, the thickness of the two-dimensional material layer is 0.5 nm to 10 μm, preferably 1 to 800 nm.

9. The preparation method according to any one of claims 1 to 7, characterized in that: In the step 4), the lamination temperature is 40 to 100° C., and the lamination heating time is 1 to 180 minutes.

10. The graphene-amorphous hexagonal boron nitride water and oxygen barrier film prepared by the method according to any one of claims 1 to 9.

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