KR101873122B1 - Graphene paper having high tensile strength and low sheet resistance and manufacturing method thereof - Google Patents

Abstract

The present invention provides a graphene paper having both high electrical conductivity and chemical stability, and a method for producing the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a graphene paper having high tensile strength and low sheet resistance and a method of manufacturing the same. BACKGROUND ART [0002]

The present invention relates to a graphene paper having a high tensile strength and a low sheet resistance, and a method for producing the same.

Lightweight, paper-like flexible materials have recently emerged as the materials for electronic products, energy storage devices, and chemical filters. In particular, materials such as paper containing carbon nanotubes (CNTs) have high electrical conductivity and capacitance, and research is being conducted to apply them to electrodes. However, since carbon nanotubes are expensive and are not easily dispersed stably, their cost efficiency is low, and materials containing them are difficult to mass-produce.

Graphene refers to a polycyclic aromatic molecule formed by covalent bonding of a plurality of carbon atoms to each other, and the carbon atoms connected by the covalent bond form a 6-membered ring as a basic repeating unit, but a 5-membered ring and / It is also possible to further include a torus. The graphene thus appears as a single layer of covalently bonded carbon atoms (usually sp2 bonds). The graphene may be formed of a single layer, but it is also possible to stack a plurality of the graphenes to form a plurality of layers, and a thickness of up to about 100 nm is formed. Furthermore, graphene has been used as a core material for electronic products due to its high specific surface area, flexibility, physical strength, thermal chemical stability and high electrical conductivity. Furthermore, graphene paper has stronger tensile behavior and stronger inter-surface bonding than carbon nanotubes.

Graphene paper is known to improve electrical and electrochemical properties through the reduction of solvothermal graphene oxide. However, in the case of oxidized graphene, the reducing agent necessary for the reduction of the thermal solvent is harmful and the graphene paper is damaged in the reduction process. Therefore, its application is limited. Therefore, there is a need for an alternative method of obtaining graphene paper by reducing the graphene oxide.

In connection with the above problems, attempts have been made to mix non-oxidative graphene with polymers or metal materials to produce electrodes with high electrical conductivity, chemically stable and structurally stable paper . Particularly, cellulose paper among polymers is attracting attention because of its high flexibility and low cost.

Recently, studies on the applicability of flexible materials having high electrical conductivity and excellent tensile strength obtained by a combination of cellulose paper and graphene to electronic products have been reported. However, graphene paper which simultaneously achieves structural stability and high conductivity No research has been conducted on the manufacturing method.

Korean public disclosure: 10-2016-0090932 Korean public disclosure: 10-2015-0094241

The present invention provides graphene paper having high electrical conductivity and chemical stability at the same time, and a method for producing the same.

One embodiment of the present invention relates to a substrate comprising a substrate layer containing a hydroxy group on its surface; An adhesive layer provided on the base layer and including a copolymer including a vinyl butyral unit unit, a vinyl alcohol unit unit, and a vinyl acetate unit unit; And an active layer comprising non-oxidized graphene provided on the adhesive layer, wherein the adhesive layer is hydrogen-bonded to the base layer and the active layer, respectively.

Another embodiment of the present invention provides a method for producing the graphene paper.

Another embodiment of the present invention provides a method of manufacturing a semiconductor device, comprising: preparing a base layer containing a hydroxy group on a surface; Preparing a bonding composition comprising a copolymer comprising a vinyl butyral unit, a vinyl alcohol unit, and a vinyl acetate unit; Applying the adhesive composition to the substrate layer to form an adhesive layer; And forming an active layer by applying a mixed solution containing non-oxidized graphene on the adhesive layer, wherein the adhesive layer is hydrogen-bonded to the base layer and the active layer, respectively .

Graphene paper according to one embodiment of the present invention has high electrical conductivity and low sheet resistance.

The graphene paper according to one embodiment of the present invention has an advantage of being chemically stable.

The graphene paper according to one embodiment of the present invention has an advantage of excellent mechanical stability (bending stability) and mechanical stability.

1 shows a method for producing graphene paper of Example 1 of the present invention.
Fig. 2 shows the bonding relationship between the base layer, the adhesive layer and the active layer of the graphene paper of Example 1 of the present invention.
3 is a scanning electron microscope (a) of the graphene paper (d) of Example 1, the cellulose paper of Comparative Example 1 (a), and the graphene paper of Comparative Examples 2 and 3 (angles (b) and FESEM).
4 is a digital camera photograph (a) of graphene paper of Example 1 and Comparative Example 3, and a digital camera photograph (b) after immersing the graphene paper of Example 1 in a strong acid and strong base solution for 24 hours.
Fig. 5 is a photograph (a) of a digital camera after the taping and desorption experiments of graphene paper of Example 1 and Comparative Example 3, and (b) a result of measuring the sheet resistance before and after the taping desorption experiment.
6 is a stress-strain curves of the graphene paper of Example 1, Comparative Example 1 and Comparative Example 3. Fig.
FIG. 7 shows the sheet resistance measurement results of the graphene sheets of Examples 1 and 3 according to the number of bending times of the compression bending test (a) and the tensile bending test (b).

When a member is referred to herein as being "on " another member, it includes not only a member in contact with another member but also another member between the two members.

Whenever a component is referred to as "comprising ", it is understood that it may include other components as well, without departing from the other components unless specifically stated otherwise.

The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

Hereinafter, the present invention will be described in more detail.

One embodiment of the present invention comprises a substrate layer comprising a hydroxy group on its surface; An adhesive layer provided on the base layer and including a copolymer including a vinyl butyral unit unit, a vinyl alcohol unit unit, and a vinyl acetate unit unit; And an active layer comprising non-oxidized graphene provided on the adhesive layer, wherein the adhesive layer is hydrogen-bonded to the base layer and the active layer, respectively.

When producing graphene paper, thermal solvent reduction of the oxidized graphene is used. However, there is a disadvantage that the reducing agent used in the thermal solvent reduction is detrimental and the structure of graphene paper is damaged due to agglomeration and reaccumulation of oxidized graphene in the reduction process.

According to one embodiment of the present invention, graphene paper can be produced by applying non-oxidized graphene to form an active layer of graphene paper, thereby simplifying the manufacturing process and providing a large amount of graphene Paper can be manufactured.

According to one embodiment of the present invention, the active layer containing non-oxidized graphene can improve the flexibility of graphene paper.

According to one embodiment of the present invention, the base layer may include at least one selected from the group consisting of cellulose fibers, glass fibers, ceramic fibers and metal fibers.

According to one embodiment of the present invention, the substrate layer may be a porous substrate.

According to one embodiment of the present invention, the substrate layer may be a porous substrate having a skeleton of at least one kind of fiber selected from the group consisting of the cellulose fibers, glass fibers, ceramic fibers and metal fibers.

According to one embodiment of the present invention, the substrate layer is a porous substrate, and the active layer may be located on the pores and the surface of the porous substrate via the adhesive layer. Specifically, the active layer may be provided on the skeleton forming the porous substrate, and may be provided on the pores of the porous substrate. Specifically, the active layer may be provided on both the surface of the porous substrate and the internal voids.

According to one embodiment of the present invention, the active layer is coated on the porous substrate, thereby improving the softness of the surface of the graphene paper, improving the bonding between the active layer inner surfaces and the electrical conductivity of the active layer.

According to one embodiment of the present invention, the copolymer contained in the adhesive layer includes an oxygen-containing unit unit, and thus can be hydrogen-bonded to the base layer and the active layer, respectively. More specifically, oxygen contained in the functional group contained in the copolymer may be hydrogen bonded to the functional group such as the hydroxyl group contained in the base layer and the active layer, respectively.

According to one embodiment of the present invention, the copolymer contained in the adhesive layer prevents structural deformation and volume expansion of the base layer through hydrogen bonding with the base layer and the active layer, respectively, so that the structural stability of the graphene paper can be maintained have.

According to one embodiment of the present invention, the copolymer contained in the adhesive layer may be one comprising a vinyl butyral unit unit, a vinyl alcohol unit unit and a vinyl acetate unit unit.

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According to one embodiment of the present invention, the vinyl butyral unit can provide structural stability to graphene paper.

According to one embodiment of the present invention, the vinyl alcohol unit unit can provide a copolymer having improved compatibility with non-oxidized graphene. Specifically, the hydroxyl group contained in the vinyl alcohol unit unit can improve the compatibility with non-oxidized graphene.

According to one embodiment of the present invention, the vinyl acetate unit unit can impart and improve adhesion to each of the active layer and the base layer. Specifically, the acetate groups contained in the vinyl acetate unit unit can improve the surface durability and adhesion of graphene paper.

According to an embodiment of the present invention, the weight average molecular weight of the copolymer contained in the adhesive layer may be 10,000 or more and 1,000,000 or less. In the case of an adhesive composition, the adhesive strength of the adhesive composition may vary depending on the molecular weight of the polymer contained in the composition. In particular, when the weight average molecular weight of the copolymer contained in the adhesive layer is less than 10,000, the adhesive strength of the adhesive layer is low and film formation may be difficult. When the weight average molecular weight is more than 1,000,000, dissolution of the adhesive composition may be difficult.

According to an embodiment of the present invention, the non-oxidized graphene contained in the active layer may be a water-dispersible graphene (WDG).

According to an embodiment of the present invention, the sheet resistance of the graphene paper may be 110? / Sq to 120? / Sq.

According to an embodiment of the present invention, the graphene paper may have a tensile strength of 37 MPa to 38 MPa.

Another embodiment of the present invention provides a method of manufacturing a semiconductor device, comprising: preparing a base layer containing a hydroxy group on a surface; Preparing a bonding composition comprising a copolymer comprising a vinyl butyral unit, a vinyl alcohol unit, and a vinyl acetate unit; Applying the adhesive composition to the substrate layer to form an adhesive layer; And forming an active layer by applying a mixed solution containing non-oxidized graphene on the adhesive layer, wherein the adhesive layer is hydrogen-bonded to the base layer and the active layer, respectively .

According to an embodiment of the present invention, the step of preparing the adhesive composition may further comprise mixing the copolymer and the alcohol in a weight ratio of 5:95 to 15:85.

According to one embodiment of the present invention, the step of forming the adhesive layer further includes a step of drying the substrate layer having the adhesive composition applied thereto at a temperature of not less than 50 ° C and not more than 70 ° C for not less than 5 minutes and not more than 15 minutes .

According to an embodiment of the present invention, the step of forming the active layer may include a step of forming a base layer on which a mixed solution containing non-oxidized graphene is applied at a temperature of 60 ° C to 70 ° C for 5 minutes to 15 minutes And drying the resultant mixture.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention is not construed as being limited to the embodiments described below. Embodiments of the present disclosure are provided to enable those skilled in the art to more fully understand the present invention.

Example  One

A bonding composition in which a poly (vinyl butyral-vinyl alcohol-vinyl acetate) [P (VB-co-VA-co-VAc)] copolymer and ethanol were mixed at a weight ratio of 10:90 was prepared. The adhesive composition was applied to a cellulose substrate (Meyer Rod & Air Knife Coater, 10 cm / s) and dried at 60 DEG C for 1 minute. Then, water-dispersed graphene was applied (Meyer Rod & Air Knife Coater, 10 cm / s) and dried at 60 DEG C for 10 minutes to obtain graphene paper.

Fig. 1 schematically shows the manufacturing process described in Example 1. Fig. More specifically, FIG. 1 shows the results obtained by applying a P (VB-co-VA-co-VAc) copolymer on a cellulose substrate, drying the cellulose acetate substrate at 60 DEG C for 1 minute, Lt; 0 > C for 10 minutes to prepare graphene paper.

Fig. 2 shows the bonding relationship between the base layer, the adhesive layer and the active layer of the graphene paper of Example 1. Fig. Specifically, FIG. 2 shows the hydrogen bonding relationship and the P (VB-co-VA-co-VAc) relationship of the adhesive layer comprising the substrate layer containing cellulose fibers and P (VB- Bond relationship between the adhesive layer including the copolymer and the active layer including the water-dispersed graphene.

Comparative Example  One

A bonding composition and a cellulose paper not coated with water-dispersed graphene were prepared.

Comparative Example  2

Graphene paper was prepared in the same manner as in Example 1, except that the step of applying water-dispersed graphene was not included.

Comparative Example  3

A graphene paper was prepared in the same manner as in Example 1, except that the step of applying the adhesive composition was not included.

<Experimental Example>

Scanning electron microscope

The graphene paper (d) of Example 1, the cellulose paper (a) of Comparative Example 1, and the (b) and (c) of Comparative Example 2 and Comparative Example 3 were subjected to scanning electron microscopy (FESEM) And the photograph is shown in Fig. 3 (S-4800, HITACHI, LTD, Japan).

Scalability scalability ) Experiment

The graphene paper of Example 1 and Comparative Example 3 was made into a size of 210 mm × 297 mm and each was photographed with a digital camera. The photograph is shown in FIG. 4 (a).

Acid base  Resistance experiment

The graphene paper of Example 1 was produced in a size of 210 mm x 297 mm. Thereafter, each sample was immersed in 0.2 M hydrochloric acid (HCl) solution and 0.2 M sodium hydroxide (NaOH) solution for 24 hours, respectively, and each was photographed with a digital camera, and the photograph is shown in FIG. 4 (b).

Tape experiment and sheet resistance measurement experiment

Tape was attached to the graphene paper of Example 1 and Comparative Example 3 and peeled off. Fig. 5 (a) shows a photograph of a digital camera after detachment of the tape.

The sheet resistance of the prepared graphene paper of Example 1 and Comparative Example 3 was measured before and after the tape test (Loresta EP MCP-T360, OAI Instruments, USA) and the results are shown in FIG. 5 (b).

Stress-strain measurement

Strain-strain was measured (Instron-5567, Instron Co., Norwood, USA) by applying a tensile load to the graphene paper of Example 1, Comparative Example 2 and Comparative Example 3, and the result is shown in FIG.

Compression-tensile bending test

The sheet resistance of the graphene paper of Example 1 and Comparative Example 3 was measured according to the number of bending times under compression bending (a) and tensile bending (b), and the results are shown in FIG.

<Evaluation>

Scanning electron microscope

As can be seen from Fig. 3, the cellulose paper of Comparative Example 1 has a non-smooth surface and exhibits a porous structure. The graphene paper of Comparative Example 2 has a relatively smooth surface than the cellulose paper of Comparative Example 1 because it has a role of smoothing the rough surface of the cellulose fiber by P (VB-co-VA-co-VAc) .

It can be seen that the graphene paper of Example 1 has a soft surface compared to the graphene paper of Comparative Example 3 because the electrical conductivity of the graphene layer of Comparative Example 2 and the electrical conductivity of the inner surface And promoted the interaction between the two.

Scalability scalability ) Experiment

As can be seen from FIG. 4 (a), the graphene paper of Comparative Example 3 had wrinkles on the surface, while the graphene paper of Example 1 had no wrinkles. From this result, it can be confirmed that P (VB-co-VA-co-VAc) copolymer plays a role of preventing the volume expansion and structural deformation of the cellulose substrate by hydrogen bonding.

Acid base  Resistance experiment

As can be seen from FIG. 4 (b), it was confirmed that the graphene paper of Example 1 was not deformed even when it was immersed in the acidic basic solution for 24 hours. As a result of the compatibility test, it was confirmed that the P (VB-co-VA-co-VAc) copolymer plays a role of preventing the volume expansion and structural deformation of the cellulose substrate by hydrogen bonding.

Tape experiment and sheet resistance measurement experiment

As can be seen from FIG. 5 (a), unlike the graphene paper of Comparative Example 3, the graphene paper of Example 1 was found to have only a small amount of graphene grains even when the tape was attached and peeled off. 5 (b), the sheet resistance of the graphene material of Comparative Example 3 increased sharply (2700? / Sq at 3300? / Sq) before and after the tape test, It was confirmed that the change of the sheet resistance before and after the experiment was not large (117? / Sq at 115? / Sq). Through this, it was confirmed that the adhesive force between the active layer and the adhesive layer and the base layer was strong, thereby preventing desorption of graphene from the active layer.

Stress-strain measurement

As can be seen from FIG. 6, it was confirmed that the graphene paper of Example 1 had the largest tensile strength and the cellulose paper of Comparative Example 1 had the largest breaking strain. As a result, it was confirmed that the graphene paper of Example 1 was structurally uniform, the graphene of the active layer was well coated, and the graphene of the active layer restored the overall flexibility of the cellulose base material.

Compression-tensile bending test

As can be seen from Fig. 7, it was confirmed that the increase in the sheet resistance due to compression or tensile bending of the graphene paper of Comparative Example 3 was larger than the increase in the sheet resistance of the graphene paper of Example 1.

Claims (13)

A base layer containing a hydroxy group on its surface;
An adhesive layer provided on the base layer and including a copolymer including a vinyl butyral unit unit, a vinyl alcohol unit unit, and a vinyl acetate unit unit; And
And an active layer including non-oxidized graphene provided on the adhesive layer,
Wherein the adhesive layer is hydrogen-bonded to the base layer and the active layer, respectively. The method according to claim 1,
Wherein the base layer comprises at least one selected from the group consisting of cellulose fibers, glass fibers, ceramic fibers and metal fibers. The method according to claim 1,
Wherein the substrate layer is a porous substrate. The method according to claim 1,
Wherein the substrate layer is a porous substrate,
Wherein the active layer is located on the pores and surfaces of the porous substrate via the adhesive layer. delete The method according to claim 1,
Wherein the weight average molecular weight of the copolymer contained in the adhesive layer is 10,000 to 1,000,000. The method according to claim 1,
Wherein the non-oxidized graphene contained in the active layer is water-dispersible graphene (WDG). The method according to claim 1,
Wherein the sheet resistance of the graphene paper is from 110 OMEGA / sq to 120 OMEGA / sq. The method according to claim 1,
Wherein the graphene paper has a tensile strength of from 37 MPa to 38 MPa. Preparing a substrate layer comprising a hydroxy group on a surface thereof;
Preparing a bonding composition comprising a copolymer comprising a vinyl butyral unit, a vinyl alcohol unit, and a vinyl acetate unit;
Applying the adhesive composition to the substrate layer to form an adhesive layer; And
And forming an active layer by applying a mixed solution containing non-oxidized graphene on the adhesive layer,
Wherein the adhesive layer is hydrogen-bonded to the base layer and the active layer, respectively. 11. The method of claim 10,
Wherein the step of preparing the adhesive composition further comprises mixing the copolymer and the alcohol in a weight ratio of 5:95 to 15:85. 11. The method of claim 10,
Wherein the step of forming the adhesive layer further comprises a step of drying the substrate layer to which the adhesive composition has been applied for a period of not less than 5 minutes and not more than 15 minutes at a temperature of not less than 50 캜 and not more than 70 캜. The method according to claim 10, wherein the step of forming the active layer comprises: drying a substrate layer to which a mixed solution containing non-oxidized graphene has been applied at a temperature of 60 ° C to 70 ° C for 5 minutes to 15 minutes &Lt; / RTI &gt;

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