NL2032762A - Multi-layer composite barrier film based on reduced graphene oxide and preparation method and application - Google Patents

Abstract

The present invention relates to a Hmlti—layer composite barrier film based on a reduced graphene oxide and a preparation method and an application. Polyethyleneimine/graphene oxide (PEI/GO) mixed solution is prepared; a condition is controlled so that GO is reduced to the reduced graphene oxide (RGO) by PEI; the excess PEI is removed, by suction. filtration; a PEI/RGO mixture is re— dissolved le a solvent; and a layer—by—layer sol—gel Hethod is used to prepare a layer of a RGO/PEI composite film with a multi— layer brick—wall structure on a substrate. In the film preparation process of the present invention, PEI is used as a reducing agent and a matrix at the same time: reducing the graphene oxide, and using as the matrix of the composite film, and the excess PEI is removed by the suction filtration in the preparation process.

Description

MULTI-LAYER COMPOSITE BARRIER FILM BASED ON REDUCED GRAPHENE OXIDE AND PREPARATION METHOD AND APPLICATION

TECHNICAL FIELD The present invention belongs to the technical field of pack- aging films, and specifically relates to a multi-layer composite barrier film based on a reduced graphene oxide and a preparation method and an application.

BACKGROUND ART Active gases (such as oxygen) and water vapor in nature are not beneficial to long-term storage of commodities, such as: caus- ing food spoilage, damaging to microelectronic devices, and reduc- ing the service life and stability of metal devices. Therefore, the design of new-type high-performance packaging films is always a research hotspot for many years. For general inorganic barrier films, most of them have excellent intrinsic barrier properties, but are prone to generate penetrating-type pinholes or internal defects after being bended or stretched. For most polymer barrier films, its flexibility is stronger, the mechanical properties are better, and the intrinsic barrier properties are excellent, but its microstructure and barrier properties are sensitive to the ex- ternal environment, and it is prone to generate the structural changes and performance degradation with passage of time. In re- cent years, a two-dimensional inorganic nanosheet/polymer compo- site film attracts the extensive attention of people. Most of the composite films have the thicknesses in the range of tens of na- nometers to tens of micrometers, and the extremely high gas barri- er properties are provided after being coated on a substrate (such as polyethylene terephthalate (PET)). By a layer-by-layer assembly preparation method, the electrostatic effect makes nanosheets tend to be deposited flatly in the film, and thereby a compact multi- layer brick-wall structure is formed: the nanosheets are used as bricks and a polymer matrix is used as mortar. While gas molecules are migrated inside the film, they may tend to avoid the nanosheets with the extremely strong barrier properties, and pene- trate in a more tortuous path, this greatly enhances the gas bar- rier properties of the film. In the various nanosheets, a graphene {or a reduced graphene oxide) is one of the most preferred choices because of its extremely high specific surface area, excellent me- chanical properties, strong hydrophobicity and the ability to com- pletely block most of the gas molecules. So far, scientists al- ready discover a series of graphene/polymer composite barrier films with the superior gas barrier properties.

Wherein, a reduced graphene oxide/polyethyleneimine (RGO/PET) composite film is one of them having the most outstanding proper- ties. The RGO/PEI composite film prepared by a layer-by-layer self-assembly technology has a multi-layer structure, and a PEI molecular chain plays a strong binding role on a RGO sheet layer.

The composite films, while the thicknesses are in the range of hundreds of nancmeters to tens of microns, all show the extremely high gas barrier ratios, and are a very hot research object at present. However, due to the hydrophilicity of polymer materials, the film may generate a water absorption phenomenon while being exposed to the air, the plasticization of the film and the rear- rangement of the internal microstructure are caused, thereby the air permeability of the film is increased, and the service life is reduced. Therefore, in the process of film preparation, the con- tent of hydrophobic RGO should be increased, and the content of hydrophilic polymer materials should be reduced. However, composi- tions of a composite material have a great influence on its per- formance, and there is a strong interaction between them, which is a very complicated research content.

A technical scheme of the prior art 1, layer-by-layer deposi- tion of a pulling method, such as preparation of a A/B composite multi-layer barrier film, one of A and B is a graphene oxide, and the other is a polymer matrix material: firstly, a substrate (such as PET) is selected, and the substrate is subjected to convention- al chemical treatment, corona treatment and cleaning, so that the substrate has a high affinity for a deposition material. Solution of A and solution of B are prepared, and a pH value is adjusted so that the solution of A and the solution of B have different acidi-

ty and alkalinity. The different acidity and alkalinity are used in order to have a strong interaction between A and B materials during layer-by-layer deposition, and they may be closely com- bined.

The specific film forming steps are as follows: the substrate is immersed in the solution of A for a period of time, the sub- strate is cleaned and dried (a part of a solute needs to be an- nealed to stabilize the structure) after being taken out, at this time a layer of a film A is deposited on the substrate; the sub- strate is immersed in the solution of B for a period of time, the substrate is cleaned and dried (a part of the solute needs to be annealed to stabilize the structure) after being taken out, at this time a layer of the film A and a layer of a film B are depos- ited on the substrate; the above two steps are repeated, until the preset number of film layers is achieved. Finally, the A/B compo- site multi-layer film is deposited on the substrate, and in the case that the thickness of the single layer is preset reasonably, the film usually has the brick-wall structure.

Disadvantage of this technology:

1. The solute must be stably dispersed in a solvent, so the graphene oxide with the high surface activity is necessarily used. However, the hydrophilicity of the graphene oxide is not benefi- cial to gas barrier, and it contains defects, and a large number of oxygen-containing groups, and the structural stability is not as good as that of the graphene or the reduced graphene oxide.

2. The single preparation process of the film is A solution soaking-cleaning-B solution soaking-cleaning. The steps are com- plicated, the preparation time is long, and the preparation cost is high.

3. The film forming condition is affected by many aspects to- gether, such as: the pH value, the soaking time, the solution con- centration, and the solute activity. The control condition is com- plicated, and the research difficulty is large.

In the prior art, layer-by-layer deposition of a blade coat- ing method, namely a layer-by-layer sol-gel method, such as prepa- ration of a A/B composite multi-layer barrier film, one of A and B is a graphene oxide, and the other is a polymer matrix material:

firstly, a substrate (such as PET) is selected, and the substrate is subjected to conventional chemical treatment, corona treatment and cleaning, so that the substrate has a high affinity for a dep- osition material. Solution of A and solution of B are prepared.

The specific film forming steps are as follows: a scraper is used to evenly apply a layer of the solution of A on the sub- strate, it waits for the solution to volatilize and is self- assembled to form a film (a part of a solute needs to be annealed to stabilize the structure), at this time a layer of a film A is deposited on the substrate; the scraper is used to apply a layer of the solution of B evenly on the substrate, it waits for the so- lution to volatilize and is self-assembled to form a film (a part of the solute needs to be annealed to stabilize the structure), at this time a layer of the film A and a layer of a film B are depos- ited on the substrate; the above two steps are repeated, until the preset number of film layers is reached. Finally, the A/B compo- site multi-layer film is deposited on the substrate, and in the case that the thickness of the single layer is preset reasonably, the film usually has the brick-wall structure.

Or AB mixed solution is directly prepared, and then the lay- er-by-layer sol-gel method is used to prepare the A/B composite multi-layer film. Namely: the scraper is used to evenly apply a layer of the AB mixed solution on a substrate, it waits for the solution to volatilize and is self-assembled to form a film (a part of a solute needs to be annealed to stabilize the structure), at this time a layer of a A/B composite film is deposited on the substrate; the above steps are repeated, until the preset number of film layers is reached. Finally, the A/B composite multi-layer film is deposited on the substrate, and in the case that the thickness of the single layer is preset reasonably, the film usu- ally has the brick-wall structure.

Disadvantage of this technology: the solute must be stably dispersed in the solvent, so the graphene oxide with the high sur- face activity is necessarily used. However, the hydrophilicity of the graphene oxide is not beneficial to gas barrier, and it con- tains defects, and a large number of oxygen-containing groups, and the structural stability is not as good as that of the graphene or the reduced graphene oxide.

In a suction filtration film forming method of the prior art, solution of A and solution of B are firstly prepared, one of A and B is the graphene oxide, and the other is the polymer matrix mate- 5 rial. The solution of A and the solution of B are mixed as re- quired, and then a material with small holes is used as a filter membrane (such as acetate fiber filter cloth), and AB mixed solu- tion is suction-filtered. The A/B composite film is deposited on the filter membrane.

A substrate (such as PET) is selected, and the substrate is subjected to conventional chemical treatment, corona treatment and cleaning, so that the substrate has a high affinity for a deposi- tion material. The A/B composite film left on the filter membrane is transferred to the substrate, namely the A/B composite multi- layer film coated on the substrate is prepared.

Disadvantage of this technology: After the film is formed by suction filtration, the film is deposited on the filter cloth. In a later stage, the film needs to be transferred from the filter cloth to the substrate. The film is very thin, the transfer diffi- culty is large, and the transfer process is prone to generate de- fects.

SUMMARY The present invention provides a multi-layer composite barri- er film based on a reduced graphene oxide and a preparation method and an application. In the process of preparing the film, a gra- phene oxide is reduced, and finally the high-performance multi- layer composite barrier film based on the reduced graphene oxide and coated on a substrate with the relatively low polymer matrix content is prepared.

A specific technical scheme is as follows: A preparation method for a multi-layer composite barrier film based on a reduced graphene oxide includes the following steps: preparing PEI/GO mixed solution; controlling a condition so that GO is reduced to RGO by PEI; removing the excess PEI by suction filtration; re-dissolving a PEI/RGO mixture in a solvent; and using a layer-by-layer sol-gel method to prepare a layer of a RGO/PEI composite film with a multi-layer brick-wall structure on a substrate.

Specifically: Sl. Selecting and performing conventional chemical treatment, corona treatment and cleaning on the film substrate, so that the substrate has a high affinity for a deposition material; S2. adding a certain amount of graphene oxide powder to de- ionized water, ultrasonically stirring to disperse the graphene oxide powder and converting into a single-layer structure, namely preparing single-layer GO solution; S3. adding a certain concentration of PEI solution to the GO solution, and stirring to mix uniformly; S84. placing mixed solution under a condition of 80°C and stirring; using PEI as a reducing agent to reduce or partially re- duce GO to RGO; and at the same time, adsorbing some PEI molecules on the RGO surface in a chemical modification or physical adsorp- tion mode; S5. using filter cloth, suction-filtering the mixed solution after the reaction, and leaving a mixture of RGO and PEI on the filter cloth; S6. using warm water to continuously suction-filter and wash the mixture of RGO and PEI on the filter cloth, to remove the ex- cess PEI molecules; S7. scraping off the mixture of RGO and PEI on the filter cloth, ultrasonically treating and stirring, to re-dissolve and disperse in the deionized water, and preparing new RGO/PEI mixed solution; S8. placing the pre-treated film substrate horizontally, and fixing; S9. according to the concentration of the RGO/PEI mixed solu- tion, taking out a certain amount of the mixed solution, wherein the mixed solution taken out should be able to form a composite film of which the thickness is smaller than the maximum diameter of RGO on the substrate; S10. using an applicator or a scraper to spread the mixed so- lution taken out uniformly on the substrate, and standing to form a film, wherein the film forming process controls the condition such as the temperature, the humidity and the blast as required; S11. acquiring a RGO/PEI composite film coated on the sub- strate; S12. repeating the steps S9-11, wherein the amount of the mixed solution taken out every time should be equal; and S13. after a certain number of repetitions, acquiring a layer of a RGO/PEI composite film with a multi-layer structure (brick- wall structure) and deposited on the substrate.

The multi-layer composite barrier film based on the reduced graphene oxide obtained in the present invention may be used as a packaging material, especially a packaging material for food.

In the film preparation process of the present invention, PEI is used as a reducing agent and a matrix at the same time: reduc- ing the graphene oxide, and using as the matrix (mortar structure) of the composite film, and the excess PEI is removed by the suc- tion filtration in the preparation process, so the content of the hydrophilic PEI in the composite film is effectively reduced (PEI is needed and very important, but too much PEI causes the film to absorb water, which is not beneficial to its barrier properties), and the high-performance multi-layer composite barrier film based on the reduced graphene oxide with the low PEI content is pre- pared.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a RGO/PEI-0.05 composite film prepared in Embodi- ment 1; FIG. 2 is a RGO/PEI-0.1 composite film prepared in Embodiment 2; and FIG. 3 is a RGO/PEI-0.3 composite film prepared in Embodiment

3.

DETAILED DESCRIPTION OF THE EMBODIMENTS Specific technical schemes of the present invention are de- scribed with reference to embodiments. Embodiment 1 A piece of 10 cmx10 cm PET with a thickness of 35pm is taken as a substrate, washed with deionized water and methanol, and sub- jected to a corona treatment to improve its affinity. A certain amount of graphene oxide powder (the outer diameter is 0.5-3 um, and <3 layers) is mixed with the deionized water, 10 w ultrasonic treatment is performed for 10 minutes, and supplemented by stir- ring, to prepare 100 mL of single-layer GO aqueous solution with a concentration of 0.1 mg mL*. 100 mL of PEI solution with a concen- tration of 0.05 mg mL’ is added to the GO aqueous solution, and it is stirred to mix uniformly. Mixed solution is placed under a con- dition of 80°C and stirred for 3 hours, and the color of the solu- tion is changed from brown to black, namely the reduction of the graphene oxide is achieved. Cellulose acetate filter paper with holes of 0.2 um is used, the mixed solution after the reaction is suction-filtered, and it is washed with warm water for many times. A RGO and PEI mixture on filter cloth is scraped off, ultrasoni- cally treated and stirred, to re-dissolve and disperse in deion- ized water, and RGO/PEI mixed solution with a total solute content of 0.5wt% is prepared. A pre-treated film substrate is placed hor- izontally, and fixed. 1 mL of the mixed solution is taken out, the mixed solution taken out is evenly spread on the substrate with a spreader or a scraper, and it is stood at 60°C to form a film. A total of 20 times of spreading of the mixed solution and standing to form a film are performed, and finally a layer of a RGO/PEI-

0.05 composite film with a multi-layer brick-wall structure is coated on the substrate, as shown in FIG. 1.

According to an analytical test, after the PET substrate is coated with the RGO/PEI-0.05 composite film, its gas permeability is decreased from 54.86 cm’ m° day* atm™ to 0.94 cm m™ day? atm !. The coating layer shows the extremely efficient gas barrier properties.

Embodiment 2 A piece of 10 cmx10 cm PET with a thickness of 35um is taken as a substrate, washed with deionized water and methanol, and sub- jected to a corona treatment to improve its affinity. A certain amount of graphene oxide powder (the outer diameter is 0.5-3 pm, and <3 layers) is mixed with the deionized water, 10 w ultrasonic treatment is performed for 10 minutes, and supplemented by stir-

ring, to prepare 100 mL of single-layer GO aqueous solution with a concentration of 0.1 mg mL*. 100 mL of PEI solution with a concen- tration of 0.1 mg mL } is added to the GO aqueous solution, and it is stirred to mix uniformly. Mixed solution is placed under a con- dition of 80°C and stirred for 3 hours, and the color of the solu- tion is changed from brown to black, namely the reduction of the graphene oxide is achieved. Cellulose acetate filter paper with holes of 0.2 um is used, the mixed solution after the reaction is suction-filtered, and it is washed with warm water for many times. A RGO and PEI mixture on filter cloth is scraped off, ultrasoni- cally treated and stirred, to re-dissolve and disperse in deion- ized water, and RGO/PEI mixed solution with a total solute content of 0.5wt% is prepared. A pre-treated film substrate is placed hor- izontally, and fixed. 1 mL of the mixed solution is taken out, the mixed solution taken out is evenly spread on the substrate with a spreader or a scraper, and it is stood at 60°C to form a film. A total of 20 times of spreading of the mixed solution and standing to form a film are performed, and finally a layer of a RGO/PEI-0.1 composite film with a multi-layer brick-wall structure is coated on the substrate, as shown in FIG. 2.

According to an analytical test, after the PET substrate is coated with the RGO/PEI-0.1 composite film, its gas permeability is decreased from 54.86 cm’ m° day atm! to 0.25 cm m° day atm t, The coating layer shows the extremely efficient gas barrier properties.

Embodiment 3 A piece of 10 cmx10 cm PET with a thickness of 35um is taken as a substrate, washed with deionized water and methanol, and sub- jected to a corona treatment to improve its affinity. A certain amount of graphene oxide powder (the outer diameter is 0.5-3 pum, and <3 layers) is mixed with the deionized water, 10 w ultrasonic treatment is performed for 10 minutes, and supplemented by stir- ring, to prepare 100 mL of single-layer GO aqueous solution with a concentration of 0.1 mg mL. 100 mL of PEI solution with a concen- tration of 0.3 mg mL* is added to the GO aqueous solution, and it is stirred to mix uniformly. Mixed solution is placed under a con- dition of 80°C and stirred for 3 hours, and the color of the solu-

tion is changed from brown to black, namely the reduction of the graphene oxide is achieved. Cellulose acetate filter paper with holes of 0.2 pm is used, the mixed solution after the reaction is suction-filtered, and it is washed with warm water for many times. A RGO and PEI mixture on filter cloth is scraped off, ultrasoni- cally treated and stirred, to re-dissolve and disperse in deion- ized water, and RGO/PEI mixed solution with a total solute content of 0.5wt% is prepared. A pre-treated film substrate is placed hor- izontally, and fixed. 1 mL of the mixed solution is taken out, the mixed solution taken out is evenly spread on the substrate with a spreader or a scraper, and it is stood at 60°C to form a film. A total of 20 times of spreading of the mixed solution and standing to form a film are performed, and finally a layer of a RGO/PEI-0.3 composite film with a multi-layer brick-wall structure is coated on the substrate, as shown in FIG. 3.

According to an analytical test, after the PET substrate is coated with the RGO/PEI-0.05 composite film, its gas permeability is decreased from 54.86 cm’ m° day? atm: to 0.17 cm’ m° day* atm. The coating layer shows the extremely efficient gas barrier properties.

Claims (6)

CONCLUSIESCONCLUSIONS 1. Werkwijze voor de vervaardiging van een meerlaagse composiet barrièrefilm op basis van een gereduceerd grafeenoxide, met het kenmerk, dat de werkwijze de volgende stappen omvat: het bereiden van een gemengde oplossing van polyethyleenimi- ne/grafeenoxide (PEI/GO); het beheersen van een toestand zodat GO wordt gereduceerd tot het gereduceerde grafeenoxide (RGO) door PEI; het verwijderen van de overmaat PEI door afzuigfiltratie; het opnieuw oplossen van een PEI/RGO-mengsel in een oplosmiddel; en het toepassen van een laag-voor-laag sol-gel-methode om een laag van een RGO/PEI-composietfilm met een meerlaagse bakstenen muur- structuur op een substraat te maken.A method for the production of a multilayer composite barrier film based on a reduced graphene oxide, characterized in that the method comprises the following steps: preparing a mixed solution of polyethyleneimine/graphene oxide (PEI/GO); controlling a state such that GO is reduced to the reduced graphene oxide (RGO) by PEI; removing the excess PEI by suction filtration; redissolving a PEI/RGO mixture in a solvent; and applying a layer-by-layer sol-gel method to make a layer of an RGO/PEI composite film having a multilayer brick wall structure on a substrate. 2. Werkwijze voor de vervaardiging van de meerlaagse composiet barrièrefilm op basis van het gereduceerde grafeenoxide volgens conclusie 1, met het kenmerk, dat de werkwijze de volgende stappen omvat: Sl. het selecteren en uitvoeren van conventionele chemische behan- deling, coronabehandeling en reiniging op het filmsubstraat, zodat het substraat een hoge affiniteit heeft voor een depositiemateri- aal; S2. het toevoegen van een bepaalde hoeveelheid grafeenoxidepoeder aan gedeïoniseerd water, het ultrasoon roeren om het grafeenoxide- poeder te dispergeren en het omzetten in een enkellaagse struc- tuur, namelijk het bereiden van een enkellaags GO-oplossing; S3. het toevoegen van een bepaalde concentratie PEI-oplossing aan de GO-oplossing, en het roeren om het uniform te mengen; S4. het plaatsen van de gemengde oplossing onder een conditie van 80 °C en roeren; PEI gebruiken als reductiemiddel om GO tot RGO te reduceren of gedeeltelijk te reduceren; en tegelijkertijd het ad- sorberen van sommige PEI-moleculen op het RGO-oppervlak in een chemische modificatie of fysische adsorptiemodus; S5. het gebruiken van filterdoek, en het daarmee uitvoeren van zuig-filtratie op de gemengde oplossing na de reactie, en het ach- terlaten van een mengsel van RGO en PEI op het filterdoek ; S6. het gebruiken van warm water voor het continu uitvoeren van zuigfiltratie en wassen van het mengsel van RGO en PEI op het fil- terdoek, om de overtollige PEI-moleculen te verwijderen; S7. het mengsel van RGO en PEI van het filterdoek afschrapen, ul- trasoon behandelen en roeren om opnieuw op te lossen en te disper- geren in het gedeïoniseerde water, en een nieuwe gemengde RGO/PEI- oplossing bereiden; S8. het horizontaal plaatsen van het voorbehandelde filmsubstraat, en fixeren; S9. het in overeenstemming met de concentratie van de gemengde RGO/PEI-oplossing, verwijderen van een bepaalde hoeveelheid van de gemengde oplossing, waarbij de uitgenomen gemengde oplossing een composietfilm moet kunnen vormen waarvan de dikte kleiner is dan de maximale diameter van RGO op het substraat;The method for manufacturing the multilayer composite barrier film based on the reduced graphene oxide according to claim 1, characterized in that the method comprises the following steps: S1. selecting and performing conventional chemical treatment, corona treatment and cleaning on the film substrate so that the substrate has a high affinity for a deposition material; S2. adding a certain amount of graphene oxide powder to deionized water, ultrasonic stirring to disperse the graphene oxide powder, and converting it into a single-layer structure, namely, preparing a single-layer GO solution; S3. adding a certain concentration of PEI solution to the GO solution, and stirring to mix it uniformly; S4. placing the mixed solution under a condition of 80°C and stirring; Using PEI as a reducing agent to reduce or partially reduce GO to RGO; and simultaneously adsorbing some PEI molecules on the RGO surface in a chemical modification or physical adsorption mode; S5. using filter cloth, and therewith performing suction filtration on the mixed solution after the reaction, and leaving a mixture of RGO and PEI on the filter cloth; S6. using hot water to continuously perform suction filtration and wash the mixture of RGO and PEI on the filter cloth to remove the excess PEI molecules; S7. scrape the mixture of RGO and PEI off the filter cloth, ultrasonicate and stir to redissolve and disperse in the deionized water, and prepare a new mixed RGO/PEI solution; S8. placing the pre-treated film substrate horizontally, and fixing; S9. removing a certain amount of the mixed solution in accordance with the concentration of the mixed RGO/PEI solution, wherein the taken out mixed solution must be able to form a composite film whose thickness is smaller than the maximum diameter of RGO on the substrate; 510. het gebruiken van een applicator of een schraper om de uitge- nomen gemengde oplossing gelijkmatig op het substraat te versprei- den en te laten staan om een film te vormen, waarbij het filmvor- mende proces de conditie regelt zoals nodig is; S11. het verkrijgen van een RGO/PEI-composietfilm die op het sub- straat is gecoat; S12. het herhalen van de stappen S9 tot S11; en S13. na een bepaald aantal herhalingen, het verkrijgen van een laag van een RGO/PEI-composietfilm met een meerlaagse bakstenen muurstructuur en die op het substraat is afgezet.510. Using an applicator or a scraper to evenly spread the extracted mixed solution on the substrate and allow it to stand to form a film, the film-forming process controlling the condition as needed; S11. obtaining an RGO/PEI composite film coated on the substrate; S12. repeating steps S9 to S11; and S13. after a certain number of repetitions, obtaining a layer of an RGO/PEI composite film having a multilayer brick wall structure and deposited on the substrate. 3. Werkwijze voor de vervaardiging van de meerlaagse composiet barrièrefilm op basis van het gereduceerde grafeenoxide volgens conclusie 2, met het kenmerk, dat het filmvormingsproces van S10 de temperatuur, vochtigheid en ontploffingsconditie regelt zoals die nodig zijn.The method for manufacturing the multilayer composite barrier film based on the reduced graphene oxide according to claim 2, characterized in that the film-forming process of S10 controls the temperature, humidity and blasting condition as needed. 4. Werkwijze voor de vervaardiging van de meerlaagse composiet barrièrefilm op basis van het gereduceerde grafeenoxide volgens conclusie 2, met het kenmerk, dat, in het filmvormingsproces van S10, terwijl de stappen S9 tot S11 worden herhaald volgens S12, de hoeveelheid van de gemengde oplossing die elke keer wordt genomen, gelijk moet zijn.The method for manufacturing the multilayer composite barrier film based on the reduced graphene oxide according to claim 2, characterized in that , in the film-forming process of S10, while repeating the steps S9 to S11 according to S12, the amount of the mixed solution taken each time must be the same. 5. Meerlaagse composiet barrièrefilm op basis van een gereduceerd grafeenoxide, met het kenmerk, dat deze wordt verkregen door de werkwijze voor de vervaardiging volgens een van de conclusies 1 tot en met 4.A multilayer composite barrier film based on a reduced graphene oxide, characterized in that it is obtained by the manufacturing method according to any one of claims 1 to 4. 6. Toepassing van de meerlaagse samengestelde barrièrefilm op ba- sis van het gereduceerde grafeenoxide volgens conclusie 5, met het kenmerk, dat het wordt gebruikt als verpakkingsmateriaal.Use of the multilayer composite barrier film based on the reduced graphene oxide according to claim 5, characterized in that it is used as a packaging material.