WO2017179900A1

WO2017179900A1 - Graphene fiber and manufacturing method therefor

Info

Publication number: WO2017179900A1
Application number: PCT/KR2017/003930
Authority: WO
Inventors: 한태희; 박헌
Original assignee: 한양대학교 산학협력단
Priority date: 2016-04-11
Filing date: 2017-04-11
Publication date: 2017-10-19

Abstract

Provided is a method for manufacturing graphene fiber comprising the steps of: preparing a source solution comprising graphene oxides; spinning the source solution with a base solution comprising heterogeneous elements to produce oxidized graphene fiber; separating, washing and drying the graphene fiber from the base solution to obtain the oxidized graphene fiber comprising the heterogeneous elements; and subjecting the dried oxidized graphene fiber comprising the heterogeneous elements to thermal treatment to produce graphene fiber doped with the heterogeneous elements, wherein the elongation percentage of the graphene fiber is controlled according to the concentration and the spinning speed of the source solution.

Description

Graphene fiber and its manufacturing method

The present invention relates to a graphene fiber and a method for producing the same, and more particularly, a method for preparing a source solution containing graphene oxide having pores formed by adding graphene oxide, an oxidizing agent, and a pH adjusting agent to a solvent; The present invention relates to a method for producing a porous graphene fiber in which the elongation is easily controlled by adjusting the concentration and the spinning speed of the source solution.

Graphene is the most excellent material among the existing materials with various characteristics such as strength, thermal conductivity and electron mobility. Accordingly, it is applied to various fields such as display, secondary battery, solar cell, automobile, and lighting, and is recognized as a strategic core material that will lead the growth of related industries, and technology for commercializing graphene is receiving much attention.

Recently, in order to apply useful mechanical and electrical properties of graphene to various industrial fields, researches on various processes for obtaining graphene oxide from graphite raw materials have been actively conducted.

For example, in the Republic of Korea Patent Publication No. KR20140045851A (Application No. KR20120112103A, Grapheneol Co., Ltd.), using an acid to oxidize graphite to form a primary reaction product containing graphene oxide, from the primary reaction product Recovering the acid, and using the recovered acid to oxidize the graphite to form a recycle reaction product comprising graphene oxide, which facilitates separation of the acid from the graphene oxide product in a relatively short time, Disclosed are techniques for producing graphene oxide that can reduce the disposal rate of toxic process by-products such as acids.

In order to commercialize graphene into various industrial fields, it is possible to reduce the processing cost and processing time with a simplified process, and to manufacture graphene, which is capable of subsequent processing of graphene to control the properties of graphene according to the application field. There is a need for research.

One technical problem to be solved by the present invention is to provide a graphene fiber excellent in elongation and a manufacturing method thereof.

Another technical problem to be solved by the present invention is to provide a graphene fiber excellent in mechanical properties and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a graphene fiber having a flexible characteristic and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a graphene fiber excellent in electrical conductivity and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a graphene fiber having a porous structure and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a graphene fiber and a method of manufacturing the reduced process cost and process time.

Another technical problem to be solved by the present invention is to provide a graphene fiber and a method of manufacturing the same for easy mass production.

Another technical problem to be solved by the present invention is to provide a high graphene fiber and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a graphene fiber of high orientation and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a graphene fiber and a method for manufacturing the same that can be a subsequent process.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above technical problem, the present invention provides a method for producing a graphene fiber.

According to one embodiment, the graphene fiber manufacturing method, preparing a source solution containing graphene oxide (graphene oxide), spinning the source solution with a base solution containing a heterogeneous element graphene oxide fiber Preparing, separating, washing, and drying the graphene fibers from the base solution to obtain graphene oxide fibers including the dissimilar elements, and dried graphene oxide fibers including the dissimilar elements. Thermal treatment to prepare the graphene fibers doped with the dissimilar elements, wherein the elongation percentage of the graphene fibers is controlled according to the concentration and spinning rate of the source solution. It may include.

According to one embodiment, the method for producing the graphene fiber may include increasing the elongation of the graphene fiber as the concentration of graphene oxide in the source solution increases.

According to one embodiment, the manufacturing method of the graphene fiber may include increasing the elongation of the graphene fiber as the spinning speed of the source solution decreases.

According to one embodiment, the graphene fiber manufacturing method, in the step of obtaining a graphene oxide fiber comprising the heterogeneous element, drying and winding the graphene oxide fiber comprising the heterogeneous element at the same time It may further include.

According to one embodiment, the manufacturing method of the graphene fiber, when the spinning speed of the source solution is larger than the winding speed of the graphene oxide fiber containing the dissimilar elements, the elongation of the graphene fiber includes increasing can do.

According to an embodiment, the manufacturing of the graphene fiber may include reducing the graphene oxide fiber to the graphene fiber through the heat treatment, and the heterogeneous element included in the graphene oxide fiber may be used. And may be doped into the pin fibers.

According to another embodiment, the method for producing the graphene fibers, preparing a source solution in which a graphene oxide sheet (graphene oxide sheet) is dispersed, a reducing agent for partially reducing the graphene oxide sheet (partially), And spinning the source solution in a coagulation bath simultaneously comprising a binder for binding the graphene oxide sheets to obtain graphene oxide fibers, and reducing the graphene oxide fibers, It may include the step of producing the graphene fibers.

According to another embodiment, the graphene fiber manufacturing method, the graphene oxide sheet is partially reduced by the reducing agent, a partially reduced graphene oxide sheet (partially reduced graphene oxide sheet) is produced In addition, pi-pi stacking (π-π stacking) between the partially reduced graphene oxide sheets may include an increase in tensile strength of the graphene oxide fibers.

According to another embodiment, the binder may include divalent or trivalent metal ions.

According to another embodiment, the method for manufacturing the graphene fiber may further comprise the step of producing a copper plated graphene fiber by copper plating the graphene fiber.

According to one embodiment, the step of preparing the copper-plated graphene fibers, the step of etching the graphene fibers, bonding the catalyst metal to the etched graphene fibers, and the solution containing copper Dipping the graphene fiber to which a catalyst metal is bonded, and reducing the copper using the catalyst metal, may include plating the graphene fiber with copper.

According to another embodiment, the copper plated graphene fibers may include pores provided between the graphene sheets in which the graphene oxide sheet is reduced, or copper structures provided on the surface of the graphene fibers. have.

According to another embodiment, the step of preparing the graphene fibers, the step of drying the graphene oxide fibers, washing and drying the dried graphene oxide fibers, and the washed and dried graphene oxide Dipping the fibers in a reducing solution to heat treatment, may comprise the step of reducing the graphene oxide fibers.

According to another embodiment, the source solution may further include carbon nanotubes, and the graphene fiber may further include the carbon nanotubes.

According to another embodiment, the graphene fiber manufacturing method, a graphene oxide, an oxidizing agent, and a pH adjusting agent is added to a solvent, and then reacting to prepare a source solution in which graphene oxide having voids is dispersed Preparing a graphene oxide fiber by spinning the source solution with a source solution containing a dissimilar element; separating, washing, and drying the graphene oxide fiber from the source solution; Obtaining pin fibers, thermally treating the dried graphene oxide fibers including the heterogeneous elements to produce graphene fibers doped with the heterogeneous elements, and converting the graphene fibers into a first oxidant Reacting with an aqueous solution comprising a, it may include the step of forming the fine pores in the graphene fibers.

According to another embodiment, the graphene fiber manufacturing method may include increasing the porosity of graphene oxide as the content of the oxidant in the source solution increases.

According to another embodiment, the graphene fiber manufacturing method may include increasing the porosity of graphene oxide as the pH of the source solution is higher.

According to another embodiment, the graphene fiber manufacturing method, the porosity of the fine pore formed in the graphene fiber is to be adjusted according to the content of the first oxidant in the aqueous solution and the temperature and time of the reaction. Can be.

According to another embodiment, the graphene fiber manufacturing method, the porosity in the graphene oxide in the source solution may be adjusted according to the content of the oxidant in the source solution, the pH of the source solution, and the reaction temperature. have.

According to another embodiment, the manufacturing of the graphene fibers may include reducing the graphene oxide fibers to the graphene fibers through the heat treatment, and simultaneously dissociating the heterogeneous elements included in the graphene oxide fibers. It may include doping (graphed) to the graphene fiber, it may include that the electrical conductivity of the graphene fiber is adjusted according to the content of the heterogeneous element doped in the graphene oxide fiber.

According to an embodiment of the present invention, by producing a graphene oxide fiber by spinning a source solution containing graphene oxide with a heterogeneous element or a base solution containing a reducing agent and a binder, by heat or acid treatment, excellent mechanical strength and Graphene fibers can be provided that have electrical conductivity and at the same time have high tensile modulus.

In preparing the graphene fibers, the concentration of graphene oxide in the source solution used, the spinning rate of the source solution spun into the base solution, the winding speed of the graphene oxide fiber comprising the heterogeneous element, and / or By adjusting the length of the drying zone in which the graphene oxide fibers including the heterogeneous elements are disposed, the degree of orientation of the graphene fibers may be easily adjusted.

In the case of the graphene fibers having a low degree of orientation, the porosity of the graphene fibers may be increased to provide the graphene fibers having excellent elongation. Accordingly, the graphene fibers having high mechanical strength and excellent elongation can be realized, so that the graphene fibers can be provided in various fields including flexible devices.

In addition, since the graphene fiber has a porous structure, the surface area is wide, and can serve as a natural fiber, and can be widely used in conventional membrane applications such as fibrous electronic devices.

In addition, by controlling the type and / or content of the heterogeneous element doped in the graphene fiber, the graphene fiber electrical conductivity can be easily adjusted. As such, the graphene fiber according to the embodiment of the present invention may be utilized in various fields requiring excellent electrical conductivity characteristics.

1 is a flowchart illustrating a method for manufacturing graphene fiber according to a first embodiment of the present invention.

2 is a view for explaining a manufacturing method of the graphene fiber according to the first embodiment of the present invention.

3 is a view for explaining the orientation and elongation of the graphene fiber according to the first embodiment of the present invention.

4 is a flowchart illustrating a method of manufacturing graphene fibers according to a second embodiment of the present invention.

5 is a view for explaining the function of the binder included in the coagulation bath used in the method for producing a graphene fiber according to an embodiment of the present invention.

6A and 6B are views for explaining copper plated graphene fibers manufactured according to the method for manufacturing graphene fibers according to the first modification of the second embodiment of the present invention.

7 is a flowchart illustrating a method for preparing a source solution for producing graphene fibers according to a third embodiment of the present invention.

8 is a view for explaining a method for producing a source solution for the production of graphene fibers according to a third embodiment of the present invention.

FIG. 9 is an enlarged view of a portion A of FIG. 8 and illustrates a graphene oxide having voids according to a third embodiment of the present invention.

FIG. 10 is an enlarged view of B of FIG. 9 and illustrates a detailed structure of graphene oxide having voids according to a third embodiment of the present invention.

11 is a flowchart illustrating a method for manufacturing graphene fiber according to a third embodiment of the present invention.

12 is a photograph showing a process in which a source solution is spun through a spinneret to produce graphene oxide fibers according to a first embodiment of the present invention.

FIG. 13 is a photograph illustrating a process in which graphene oxide fibers including heterogeneous elements according to a first embodiment of the present invention are wound by a winding roller. FIG.

14 is an image of a graphene fiber having a low degree of orientation according to the first embodiment of the present invention.

15 is an image of a graphene fiber having a high degree of orientation according to the first embodiment of the present invention.

FIG. 16 is a graph illustrating tensile strength values according to an increase in an external pressure of graphene fibers according to an exemplary embodiment of the present invention.

17 is a photograph of the graphene fibers according to the second embodiment 1, comparative example 1, and comparative example 2 of the present invention.

18 is a graph measuring the circularity of the graphene fibers according to the second embodiment 1, comparative example 1, and comparative example 2 of the present invention.

19 is a photograph of the surface of the graphene fibers according to the second embodiment 1, comparative example 1, and comparative example 2 of the present invention.

20 is a graph measuring the standard deviation of the thickness of the graphene fibers according to Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

21 is an AFM image of a graphene oxide sheet used for producing graphene fibers according to the second embodiment 2 to 4 of the present invention.

* FIG. 22 is a photograph taken after the addition of CoCl ₂ , AlCl ₃ , and FeCl ₃ to the source solution used in the preparation of graphene fibers according to Examples 2 to 4 of the present invention.

23 is a photograph taken for measuring the viscosity after the addition of CoCl ₂ , AlCl ₃ , and FeCl ₃ to the source solution used in the production of graphene fibers according to Examples 2 to 4 of the present invention.

24 is a graph showing the viscosity of a sauce solution used in the preparation of graphene fibers according to Examples 2 to 4 of the present invention and a solution to which CoCl ₂ , AlCl ₃ , and FeCl ₃ were added thereto.

25 is a storage modulus of the source solution used in the production of graphene fibers according to the second embodiment 2 to 4 of the present invention and the solution to which CoCl ₂ , AlCl ₃ , and FeCl ₃ were added thereto, respectively. One graph.

FIG. 26 is a graph showing the degree of gelation of a sauce solution used in the preparation of graphene fibers according to Examples 2 to 4 of the present invention and a solution in which CoCl ₂ , AlCl ₃ , and FeCl ₃ are added thereto.

27 is an XRD measurement graph of graphene oxide fibers according to Examples 2 to 4 of the present invention.

28 is a graph measuring mechanical strength of graphene oxide fibers according to Examples 2 to 4 of the present invention.

29 is a photograph of a graphene oxide fiber according to a second embodiment 2 of the present invention.

30 is an SEM image of graphene oxide with pores formed in accordance with a third embodiment of the present invention.

31 is a photograph of a sauce solution according to a third embodiment of the present invention.

32 is a photograph of a sauce solution according to a comparative example of a third embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the exemplary embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete, and that the spirit of the present invention can be sufficiently delivered to those skilled in the art.

In the present specification, when a component is mentioned to be on another component, it means that it may be formed directly on the other component or a third component may be interposed therebetween. In addition, in the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical contents.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Thus, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, the term 'and / or' is used herein to include at least one of the components listed before and after.

In the specification, the singular encompasses the plural unless the context clearly indicates otherwise. In addition, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, element, or combination thereof described in the specification, and one or more other features or numbers, steps, configurations It should not be understood to exclude the possibility of the presence or the addition of elements or combinations thereof. In addition, the term "connection" is used herein to mean both indirectly connecting a plurality of components, and directly connecting.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, a method of manufacturing graphene fiber according to the first embodiment of the present invention will be described.

1 is a flowchart illustrating a method for manufacturing graphene fiber according to a first embodiment of the present invention, Figure 2 is a view for explaining a method for manufacturing graphene fiber according to a first embodiment of the present invention, 3 is a view for explaining the orientation and elongation of the graphene fiber according to the first embodiment of the present invention.

1 and 2, a source solution 10 including graphene oxide may be prepared (S100). The source solution 10 may be prepared by adding graphene oxide to a solvent. According to one embodiment, the solvent may be water or an organic solvent. For example, the organic solvent may be dimethyl sulfoxide (DMSO), ethylene glycol, ethylene glycol, N-methyl-2-pyrrolidone (NMP), dimethylformamide ( dimethylformamide, DMF).

According to an embodiment, the source solution 10 may be prepared by adding graphene oxide to the organic solvent at a concentration of 2 to 20 mg / mL.

According to one embodiment, to improve the dispersibility of the graphene oxide in the solvent, a stirring process may be performed on the solvent to which the graphene oxide is added. According to an embodiment, the solvent to which graphene oxide is added may be stirred for 24 hours.

According to an embodiment, the elongation percentage of graphene fibers, which will be described later, may be adjusted according to the concentration of graphene oxide in the source solution 10. Specifically, according to the concentration of the graphene oxide in the source solution 10, the degree of orientation and porosity of the graphene fibers are adjusted, the elongation of the graphene fibers can be easily adjusted. .

According to one embodiment, as the concentration of the source solution 10 is increased, the degree of orientation of the graphene fibers is reduced, the porosity of the graphene fibers may be increased. Accordingly, as the concentration of the source solution 10 is increased, the elongation of the graphene fibers may increase.

According to one embodiment, the aqueous solution containing the oxidant is added to the source solution 10, the arrangement of the graphene in the graphene oxide contained in the source solution 10 can be controlled. Accordingly, according to the amount of the oxidant included in the source solution 10 and / or the reaction time of the source solution 10 and the aqueous solution containing the oxidant, the fine pores of the graphene fibers to be described later can be adjusted Can be.

According to one embodiment, after the aqueous hydrogen peroxide solution is added to the source solution 10, it may be reacted for 10 minutes to 4 hours at room temperature (25 ℃).

The source solution 10 is radiated into the base solution 20 containing heterogeneous elements, and thus, graphene oxide fiber 30 may be manufactured (S200). According to one embodiment, the base solution 20 may be prepared by adding a salt containing the heterogeneous element to a solvent. According to one embodiment, the salt containing a heterogeneous element is a salt containing an element other than carbon (C), nitrogen (N) salt, sulfur (S) salt, fluorine (F) salt, or It may be any one of iodine (I) salts.

For example, salts containing the heterogeneous elements are ammonium biborate tetrahydrate, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium cerium (IV) sulfate dihydrate, ammonium chloride, ammonium chromate, ammonium dichromate, ammonium dihydrogenphosphate, ammonium fluoride, ammonium formate, ammonium heptafluorotantalate (V), ammonium hexabromotellurate (IV), ammonium hexachloroiridate (III), ammonium hexachloroiridate (IV), ammonium hexachloroosmate (IV), ammonium hexachloropalladate (IV), ammonium hexachloroplatinate (IV), ammoniumIII ammonium hexachlororuthenate (IV), ammonium hexachlorotellurate (IV), ammonium hexafluorogermanate (IV), ammonium hexafluorophosphate, ammonium hexafluorophosphate, ammonium hexafluorosilicate, ammonium hexafluorostannate, ammonium hydrogen difluoride, ammonium hydrogenoxalate ammonium ammonium ammonium ammonium hydride , ammonium metatungstate hydrate, ammoniu m metavanadate, ammonium molybdate, ammonium nitrate, ammonium oxalate monohydrate, ammonium pentaborate octahydrate, ammonium perchlorate, ammonium perrhenate, ammonium perrhenate, ammonium phosphate dibasic, ammonium phosphomolybdate hydrate, ammonium sodium phosphate dibasic ethane ammonium tetrachloropalladate (II), ammonium tetrafluoroborate, ammonium tetrathiomolybdate, ammonium tetrathiotungstate, ammonium thiosulfate, ammonium titanyl oxalate monohydrate, ammonium trifluoromethanesulfonate, ammonium zirconium (IV) tetramonium (metamonium) tetracarbonate, tetrabutylate tetrafluoroborate, or tetramethylammonium formate).

According to one embodiment, the solvent, water (methanol), propanol (propanol), ethanol (ethanol), acetone (acetone), dimethyl formamide (dimethyl formamide, DMF), N-methyl- It may be any one of 2-piperidone (n-methyl-2-pyrrolidone, NMP), dimethyl sulfoxide (DMSO), or ethylene glycol.

According to one embodiment, the base solution 20 may further include a coagulant. The graphene oxide fibers 30 prepared by spinning the source solution 10 in the base solution 20 may be solidified by the coagulant included in the base solution 20.

According to one embodiment, the coagulant, calcium chloride (CaCl ₂ ), potassium hydroxide (KOH), sodium hydroxide (NaOH), sodium chloride (NaCl), copper sulfate (CuSO ₄ ), cetyltrimethylammonium bromide (CTAB) Or chitosan.

According to an embodiment, the base solution 20 may be prepared by adding a salt containing the heterogeneous element and 0 to 50 wt% of a coagulant to the solvent.

As can be seen in Figure 2, the source solution 10 contained in the first container 100, through the spinneret 120 connected to the first container 100, the second containing the base solution 20 Can be spun into the container 150. In the process of spinning the source solution 10 into the base solution 20, by the solvent exchange phenomenon, the salt containing the hetero element may be diffused into the graphene oxide fiber 30.

According to one embodiment, the elongation of the graphene fibers to be described later may be adjusted according to the speed of the source solution 10 that is radiated into the base solution 20. Specifically, according to the spinning speed of the source solution 10, the degree of orientation and porosity of the graphene fibers are adjusted, the elongation of the graphene fibers can be easily adjusted.

According to one embodiment, as the spinning speed of the source solution 10 is reduced, the degree of orientation of the graphene fibers is reduced, the porosity of the graphene fibers may be increased. Accordingly, as the spinning speed of the source solution 10 decreases, the elongation of the graphene fibers may increase.

In addition, according to the type and / or content of the heterogeneous elements included in the second solution, the electrical conductivity of the graphene fibers may be controlled. Specifically, the heterogeneous elements diffused into the graphene oxide fiber 30 may be doped into the graphene fiber in the thermal treatment step of S400 described later. Accordingly, by controlling the type and / or content of the heterogeneous elements contained in the base solution 20 in step S200, the electrical conductivity of the graphene fibers can be easily adjusted.

By separating, washing, and drying the graphene oxide fibers 30 from the base solution 20, the graphene oxide fibers 30 including the heterogeneous elements may be obtained (S300). The graphene oxide fiber 30 including the dissimilar elements may be separated from the second container 150 containing the base solution 20 by a guide roller 170 and then come out. The graphene oxide fiber 30 including the heterogeneous element separated from the base solution 20 may include the coagulant.

Accordingly, at least a part of the coagulant remaining in the graphene oxide fiber 30 including the dissimilar element may be removed by the washing process. According to one embodiment, the washing solution used in the washing process may be an alcoholic aqueous solution.

According to one embodiment, through the separation and washing process, the moisture contained in the graphene oxide fiber 30 including the heterogeneous element may be naturally dried in the air.

In addition, through the heating process, the graphene oxide fibers 30 including the heterogeneous elements naturally dried in air may be secondaryly dried. In other words, at least a portion of the water remaining in the graphene oxide fiber 30 including the dissimilar element may be removed through the heating process.

According to one embodiment, the type of heater used in the heating step is not particularly limited. For example, the heater may be any one of a heater, a hot plate, or a heating coil.

According to one embodiment, the graphene oxide fiber 30 including the hetero element naturally dried in air is heated to a temperature of 70 to 80 ℃ by the heater, the graphene oxide fiber comprising the hetero element At least a portion of the water remaining inside 30 may be removed.

According to one embodiment, in the step of obtaining the graphene oxide fiber 30 containing the dissimilar element, the graphene oxide fiber 30 including the dissimilar element is dried at the same time through the heating process, and wound up Can be. As can be seen in Figure 2, after the washing process is finished, the graphene oxide fibers 30 including the heterogeneous elements are wound by a winding roller 190 while the drying process is performed. Can be.

According to one embodiment, by controlling the winding speed of the graphene oxide fiber 30 including the heterogeneous element, the elongation of the graphene fiber can be easily adjusted. Specifically, according to the winding speed of the graphene oxide fiber 30 including the dissimilar element, the degree of orientation and porosity of the graphene fiber is adjusted, the elongation of the graphene fiber can be easily adjusted.

According to an embodiment, when the spinning speed of the source solution 10 is greater than the winding speed of the graphene oxide fiber 30 including the dissimilar element, the degree of orientation of the graphene fibers is reduced, and the graphene The porosity of the fibers can increase. Accordingly, when the spinning speed of the source solution 10 is greater than the winding speed of the graphene oxide fiber 30 including the dissimilar element, the stretch rate of the graphene fiber may increase.

According to an embodiment, the graphene oxide fiber 30 including the heterogeneous element may be dried through a drying rack. In this case, by adjusting the length of the drying table, the elongation of the graphene oxide fiber 30 including the heterogeneous element can be easily adjusted.

According to one embodiment, when the length of the drying rod is shorter than the length of the graphene oxide fiber 30 including the heterogeneous element disposed on the drying rod, the graphene oxide fiber 30 including the heterogeneous element is As it is dried, the shrinkage phenomenon of the graphene oxide fiber 30 including the dissimilar element due to the tension generated in the axial direction of the drying table may occur relatively less. Accordingly, the degree of orientation of the graphene fibers may be reduced, and the porosity of the graphene fibers may be increased. As a result, when the length of the drying table is shorter than the length of the graphene oxide fiber 30 including the dissimilar elements disposed on the drying table, the elongation of the graphene fibers may increase.

The dried graphene oxide fiber 30 including the heterogeneous element is heat-treated, and thus, the graphene fiber doped with the heterogeneous element may be manufactured (S400). Specifically, through the heat treatment, the graphene oxide fiber 30 of the graphene oxide fiber 30 including the dissimilar element is reduced to the graphene fiber, and included in the graphene oxide fiber 30 The heterogeneous element may be doped into the graphene fiber.

As described above, according to the type and / or content of the heterogeneous element doped in the graphene fiber, the electrical conductivity of the graphene fiber can be easily adjusted. According to one embodiment, the heterogeneous element, other than carbon (C), may be any one of nitrogen (N), sulfur (S), fluorine (F), or iodine (I).

According to an embodiment, the manufacturing of the graphene fiber may include heat treatment under an inert gas or hydrogen (H ₂ ) gas atmosphere. For example, the inert gas may be any one of argon (Ar) gas or nitrogen (N ₂ ) gas.

According to an embodiment, the graphene oxide fiber 30 including the hetero element is 100 ° C. to 5000 ° C. for 10 minutes to 10 hours at an elevated temperature rate of 10 to 100 ° C./min under an inert gas or hydrogen gas atmosphere. By the heat treatment at a temperature of the, the graphene fibers doped with the different elements can be produced.

In addition, according to one embodiment, in the post-treatment process for the graphene fibers prepared through the step S400, by supporting the graphene fibers in an aqueous solution containing the oxidizing agent, by performing a hydrothermal reaction, the graphene Fine pores may be further formed in the fiber. The post-treatment process is performed on the graphene fibers, and thus the electrical and optical properties of the graphene fibers may be improved due to the micro voids formed in the graphene fibers.

According to one embodiment, the fine pores additionally formed in the graphene fibers, can be easily adjusted according to the amount of the oxidant included in the aqueous solution and the temperature and / or time at which the hydrothermal reaction is carried out. Thus, by the post-treatment process of the graphene fibers, the electrical and optical properties of the graphene fibers can be easily adjusted.

According to one embodiment, the oxidant may be hydrogen peroxide (H ₂ O ₂ ).

* According to one embodiment, the fine pores further formed in the graphene fibers, after supporting the graphene fibers in an aqueous solution of 1 to 35% hydrogen peroxide, at a temperature of 300 to 500 ℃ in a high pressure reactor, 10 It may be formed by performing the hydrothermal reaction for minutes to 4 hours.

Unlike the embodiments of the present invention described above, conventional carbon-based fibers have excellent electrical properties, thermal stability, and tensile strength, and thus are utilized in general industrial fields such as the electronic and aerospace industries. However, since the carbon-based fiber has a low elongation, there is a limit to application to a flexible device, and there is a difficulty in serving as a natural fiber. In addition, the carbon-based fibers do not include a microstructure, so the surface area is small, does not exhibit a membrane (membrane) properties, and the electrochemical properties are disadvantageous.

However, according to an embodiment of the present invention, preparing a source solution 10 containing graphene oxide, spinning the source solution 10 with a base solution 20 containing a heterogeneous element graphene oxide fiber Preparing 30, separating, washing, and drying the graphene oxide fibers 30 from the second solution 20 to obtain graphene oxide fibers 30 including the dissimilar elements, And heat-treating the graphene oxide fiber 30 including the heterogeneous element dried, thereby preparing the graphene fiber doped with the heterogeneous element, having excellent mechanical strength and having a high tensile rate. May be provided.

In preparing the graphene fibers, the concentration of graphene oxide in the source solution 10 to be used, the spinning speed of the source solution 10 spun into the base solution 20, and the graphene oxide including the heterogeneous elements By adjusting the winding speed of the pin fibers 30 and / or the length of the drying zone in which the graphene oxide fibers 30 including the dissimilar elements are disposed, the degree of orientation of the graphene fibers can be easily adjusted.

In addition, the electrical conductivity of the graphene fiber 70 can be easily controlled by adjusting the type and / or content of the heterogeneous element doped in the graphene fiber. As such, the graphene fiber according to the embodiment of the present invention may be utilized in various fields requiring excellent electrical conductivity characteristics.

Hereinafter, a method of manufacturing graphene fiber according to a second embodiment of the present invention will be described.

Unlike the method for producing graphene fibers according to the first embodiment of the present invention, the source solution containing the graphene oxide is spun into a coagulation bath including a reducing agent and a binder instead of the base solution containing a heterogeneous element, thereby providing mechanical strength and a circular shape. Disclosed is a method for producing graphene fibers with excellent degree.

4 is a flowchart illustrating a method for manufacturing graphene fiber according to a second embodiment of the present invention, Figure 5 is a binder included in the coagulation bath used in the method for producing graphene fiber according to an embodiment of the present invention A diagram for explaining the function of the.

In the description of the graphene fiber according to the second embodiment of the present invention, for the portion overlapping with the description of the method for producing the graphene fiber according to the first embodiment of the present invention shown in FIGS. Reference is made to FIGS. 1 to 3.

4 and 5, a source solution 10 in which a graphene oxide sheet is dispersed may be prepared (S110). The source solution 10 may be prepared by adding the graphene oxide sheet to a solvent. According to one embodiment, the solvent may be water or an organic solvent. For example, the organic solvent may be dimethyl sulfoxide (DMSO), ethylene glycol, ethylene glycol, N-methyl-2-pyrrolidone (NMP), dimethylformamide ( dimethylformamide, DMF).

According to an embodiment, in order to improve the dispersibility of the graphene oxide sheet in the solvent, a stirring process may be performed on the solvent to which the graphene oxide sheet is added.

According to one embodiment, according to the concentration of the graphene oxide sheet in the source solution 10, the elongation of the graphene fibers to be described later may be adjusted. Specifically, according to the concentration of the graphene oxide sheet in the source solution 10, the degree of orientation and porosity of the graphene fibers are adjusted, the elongation of the graphene fibers can be easily adjusted.

More specifically, as the concentration of the source solution 10 is increased, the degree of orientation of the graphene fibers is reduced, the porosity of the graphene fibers may be increased. Accordingly, as the concentration of the source solution 10 is increased, the elongation of the graphene fibers may increase.

According to an embodiment, the source solution 10 may not include a polymer. Accordingly, it is possible to minimize the degradation of the electrical conductivity of the graphene fiber by the polymer.

The source solution 10 including the graphene oxide sheet is spun into a coagulation bath 20 including a reducing agent and a binder to obtain a graphene oxide fiber 30 (S120).

The coagulation bath 20 may simultaneously include a reducing agent that partially reduces the graphene oxide sheet and a binder that binds the graphene oxide sheets.

The reducing agent may partially reduce the graphene oxide sheet in the graphene oxide fiber 30. Π-π stacking increases between partially reduced graphene oxide sheets, thereby increasing the mechanical strength (eg, tensile strength) of the graphene oxide fibers 30 in a gel state. can do. For example, the reducing agent may include any one of KOH or NaOH.

The binder may include divalent or trivalent metal ions. For example, the binder may include any one of CaCl ₂ , NaCl, or CuSO ₄ . As shown in FIG. 5, oxygen may be present on the surface of the graphene oxide fiber 30. In this case, divalent or trivalent metal ions contained in the binder connect oxygens on the surface of the graphene oxide fiber 30 to each other, thereby bonding the graphene oxide sheets in the graphene oxide fiber 30. Can be strengthened. Accordingly, the mechanical strength of the graphene oxide fiber 30 in the gel state may increase.

As shown in FIG. 2, the graphene oxide fiber 30 may be separated from the second container 150 containing the coagulation bath 20 by a guide roller 170 and may be released to the outside. It may be wound by a winding roller 190.

The graphene oxide fiber 30 is reduced, the graphene fiber can be produced (S130). The step of preparing the graphene fiber, the step of drying the graphene oxide fiber 30, the step of washing and drying the dried graphene oxide fiber 30, and the washed and dried graphene oxide fiber A method of thermally immersing 30 in a reducing solution may include reducing the graphene oxide fibers 30. For example, the dried graphene oxide fibers 30 may be washed using an alcoholic aqueous solution, and dried at 50 to 80 ° C. Also, for example, the reducing solution may be an aqueous hydrogen iodide solution.

According to an embodiment, after the reduction process is performed by the reducing solution, the graphene fibers may be washed and dried using an alcoholic aqueous solution.

As shown in FIG. 2, the source solution 10 contained in the first container 100 may contain the coagulation bath 20 through the spinneret 120 connected to the first container 100. It may be radiated to the second container 150. The graphene oxide fibers 30 in the gel state formed by spinning the source solution 10 are subjected to various hydraulic forces in the coagulation bath 20.

Unlike the above-described embodiment of the present invention, when the coagulation bath 20 does not include at least one of the reducing agent or the binder, the mechanical strength of the graphene oxide fiber 30 in a gel state may be low. have. In other words, when the coagulation bath 20 includes only one of the reducing agent or the binder, the degree of increase in the mechanical strength of the graphene oxide fiber 30 is low, so that The surface becomes rugged and, accordingly, the circularity of the graphene fibers produced from the graphene oxide fibers 30 can be lowered.

However, as described above, according to an embodiment of the present invention, the coagulation bath 20 may include the reducing agent and the binder at the same time, and thus, the gel of the gel state spun into the coagulation bath 20 Mechanical strength of the graphene oxide fiber 30 can be improved. Accordingly, the graphene oxide fiber 30 may have a high circularity, and the graphene fiber manufactured from the graphene oxide fiber 30 may also have a high circularity.

In addition, the reducing agent, as described above, may partially reduce the graphene oxide sheet in the graphene oxide fiber 30. On the contrary, when the reducing agent completely reduces the graphene oxide sheet, it is easy for the solvent (which was included in the source solution 10) in the graphene oxide fiber 30 to be released to the outside through a drying process. Not. However, as described above, the reducing agent in the coagulation bath 20 may partially reduce the graphene oxide sheet, so that the solvent in the graphene oxide fiber 30 is externally dried through a drying process. Can be easily released.

According to one embodiment, by adjusting the winding speed of the graphene oxide fiber 30, the elongation of the graphene fiber can be easily adjusted. As described with reference to Figures 1 to 3, according to the winding speed of the graphene oxide fiber 30, the degree of orientation of the graphene oxide sheet in the graphene oxide fiber 30 is adjusted, the graphene fiber The degree of orientation and porosity of the graphene sheet in the inside is controlled, and thus the elongation of the graphene fibers can be easily adjusted.

In other words, according to an embodiment of the present invention, the graphene oxide fiber 30 may have a high mechanical strength by the coagulation bath 20 simultaneously comprising the reducing agent and the binder, and thus, the oxidation Even if the winding speed and spinning speed of the graphene fibers 30 are adjusted, the graphene oxide fibers 30 may not be cut. In conclusion, by easily adjusting the winding speed and spinning speed of the graphene oxide fiber 30, the elongation, porosity, and orientation of the graphene sheet can be easily adjusted according to the application.

Hereinafter, methods of manufacturing graphene fibers according to modified examples of the second embodiment of the present invention will be described.

The graphene fiber according to the first modified example of the second embodiment of the present invention is further performed by performing a copper plating process on the graphene fiber manufacturing method according to the second embodiment of the present invention described with reference to FIGS. 4 and 5. Can be prepared. Accordingly, unlike the second embodiment of the present invention described above, the graphene fibers according to the first modification of the second embodiment may further include a copper structure formed on the surface or inside of the graphene fibers.

Specifically, the step of preparing the copper plated graphene fibers, the step of etching the graphene fibers, bonding the catalyst metal to the etched graphene fibers, and the catalyst metal in a solution containing copper Dipping the bonded graphene fibers, and reducing the copper using the catalytic metal, may comprise the step of plating the graphene fibers with copper. The catalytic metal may be easily bonded to the surface of the graphene fibers etched.

According to one embodiment, the graphene fibers may be etched by supporting in an acidic solution (eg, 30% HCl) or a basic solution (eg, 5-20% NaOH) at 50 ~ 90 ℃. . For example, the catalyst metal is Pd, and the bonding of the catalyst metal to the graphene fiber is performed by a method of immersing in 0.72M HCl, 0.01M PdCl ₂ and 0.04M SnCl ₂ solution for 3 to 10 minutes. Can be. In this case, Pd ions, which are catalyst metals, may be reduced by Sn, thereby binding to the graphene fibers. According to one embodiment, the step of plating the graphene fibers with copper, the graphene fibers are catalytically bonded to the electroless copper plating bath containing 5g CuSO ₄ , 25g Potassium sodium tartrate, 7g NaOH, and 10ml formaldehyde It can be carried out by a method of supporting 1 to 10 minutes.

As shown in FIG. 6A, the cross-section of the graphene fibers may include aggregates 14 of the plurality of graphene sheets and pores 16 therebetween. The copper-plated graphene fibers according to the first modification of the second embodiment of the present invention, in addition to the aggregate 14 of the plurality of graphene sheets, pores 16 provided between the graphene sheets or the graphene Copper structures 18 formed on the surface of the fibers. In other words, as shown in FIG. 6B, the copper structure 18 covers at least a portion of the surface of the graphene fibers and / or at least a portion of the pores 16 in the graphene fibers as a whole. Or partially filled.

As described above, the graphene fibers according to the first modified example of the second embodiment of the present invention may further include the copper structure 18 having high conductivity, in addition to the aggregate 14 of the graphene sheet. Accordingly, the conductivity of the graphene fiber can be improved.

According to a second modified example of the second embodiment of the present invention, the method for producing a graphene fiber according to the second embodiment of the present invention described with reference to FIGS. 4 and 5 for increasing the surface area of the graphene fiber The post-treatment process may be further performed to produce graphene fibers according to the second modification of the second embodiment of the present invention.

More specifically, after the graphene fibers are prepared, after the graphene fibers are supported in an oxidized aqueous solution, a hydrothermal reaction may be performed. Accordingly, fine pores may be formed on the surface of the graphene fiber. The surface area of the graphene fiber may be increased by the micropores formed on the surface of the graphene fiber, and thus, the capacitance value of the super capacitor manufactured using the graphene fiber may be improved.

For example, the oxidizing aqueous solution may include hydrogen peroxide, DI water, and NH ₄ OH, and the hydrothermal reaction may be performed at a process temperature of 150 ° C. for about 30 minutes.

In addition, according to a third modified example of the second embodiment of the present invention, according to the graphene fiber manufacturing method according to the second embodiment of the present invention described with reference to Figures 4 and 5, Graphene fibers may be prepared using the source solution further comprising carbon nanotubes in addition to the graphene oxide sheet.

In other words, after dispersing the graphene oxide sheet and the carbon nanotubes in the source solution, by the method described with reference to Figures 4 and 5, the spinning process using the source solution is carried out to produce a graphene oxide fiber Can be. In this case, the graphene oxide fibers may include the graphene oxide sheet and the carbon nanotubes. Accordingly, since the graphene fibers according to the third modified example of the second embodiment of the present invention, the graphene oxide sheet is reduced graphene sheet, and the carbon nanotube provided between the graphene sheet, There may be provided a method for producing the graphene fiber with improved mechanical and electrical properties.

The graphene fibers according to the second embodiment of the present invention and modified examples thereof manufactured by the above-described method may be used in various devices and devices such as wires and capacitors.

Hereinafter, a method for producing graphene fiber according to a third embodiment of the present invention will be described.

Unlike the manufacturing method of the graphene fibers according to the first and second embodiments of the present invention, by adding an oxidizing agent and a pH adjuster to the source solution containing the graphene oxide, a method for producing the graphene fibers can be easily controlled to provide.

First, referring to FIGS. 7 to 10, a method of preparing a sauce solution for producing graphene fibers according to a third embodiment of the present invention will be described in detail.

7 is a flowchart illustrating a method for preparing a source solution for the production of graphene fibers according to a third embodiment of the present invention, Figure 8 is a graph for manufacturing the graphene fiber according to a third embodiment of the present invention 9 is a view for explaining a method of preparing a source solution, FIG. 9 is an enlarged view of A of FIG. 8, and is a view for explaining graphene oxide having voids according to a third embodiment of the present invention, and FIG. 9B is an enlarged view illustrating a detailed structure of graphene oxide having voids according to a third embodiment of the present invention.

7 to 10, the graphene oxide 3, the oxidant 5, and the pH adjuster 7 may be prepared (S100).

According to an embodiment, the graphene oxide 3 may be in the form of a sheet. In addition, according to an embodiment, the graphene oxide 3 in the form of a sheet may include fine pores formed by an irregular arrangement between the graphene oxide particles constituting the graphene oxide 3. .

The oxidant 5 is a substance that reduces itself and oxidizes the graphene oxide 3, and may form pores 4 in the graphene oxide 3. According to an embodiment, the oxidant 5 may be hydrogen peroxide (H ₂ O ₂ ), which is the oxidant 5 having a high oxidizing power.

The pH regulator 7 may create a pH environment in which the graphene oxide 3 and the oxidant 5 may react. According to one embodiment, the pH adjuster (7), LiOH, NaOH, KOH, NH ₄ OH, Ca (OH) ₂ , Sr (OH) ₂ , CsOH, Ba (OH) ₂ , Mg (OH) ₂ , Cd (OH) ₂ , La (OH) ₃ , In (OH) ₃ , Nd (OH) ₃ , Gd (OH) ₃ , FeOOH, RbOH, Al (OH) ₃ , Ni (OH) ₂ , NaF, K ₂ Co ₃ , or NH ₄ ClO.

After the graphene oxide (3), the oxidizing agent (5), and the pH adjusting agent (7) are added to the solvent (8), and reacted to disperse the source solution in which the graphene oxide (3) having the pores (4) is dispersed ( 10) can be manufactured (S200).

As described above, according to an embodiment, the oxidant 3 may be hydrogen peroxide (H ₂ O ₂ ). As disclosed in the following [Formula 1] and [Formula 2], in the solvent 8, graphene oxide (3), hydrogen peroxide (H ₂ O ₂ ), which is the oxidant (5), and the pH regulator (7) When added, hydrogen peroxide (H ₂ O ₂ ) and hydroxide ions (OH ⁻ ) provided by the pH adjuster 7 may react with each other to generate HO ₂ ⁻ ions and water (H ₂ O). In addition, HO ₂ ⁻ ions may react with hydrogen peroxide (H ₂ O ₂ ) to produce · OH radicals. Since the OH radical oxidizes the graphene oxide 3, the voids 4 can be formed in the graphene oxide 3 in the sheet form.

[Equation 1]

_{_{^{H 2 O 2 + OH - →}}} HO 2 - + H 2 O

[Equation 2]

_{_{_{^{H 2 O 2 + HO 2 -}}}} → · OH + · O 2 -

According to an embodiment, as the content of the oxidant 5 in the source solution 10 increases, the porosity of the graphene oxide 3 may increase. As the content of the oxidant 5 in the source solution 10 increases, the amount of · OH radicals that are reaction products of the oxidant 5 and the pH adjuster 7 may increase. Accordingly, the number of the pores 4 in the graphene oxide 3 may be increased, thereby increasing the porosity of the graphene oxide 3 in the form of a sheet.

According to one embodiment, the content of the oxidant 3 in the source solution 10 may be 0.1 to 40wt%. If the content of the oxidant (3) in the source solution (10) is more than 40wt%, the OH radical which oxidizes the graphene oxide (3) to form the pores (4) in the graphene oxide (3) Access to graphene oxide 3 is restricted, so that the reaction efficiency for the reaction forming the voids 4 in graphene oxide 3 can be reduced. In addition, the graphene oxide 3 may be aggregated and precipitated in the source solution 10.

According to one embodiment, as the pH of the source solution 10 is higher, the porosity of the graphene oxide 3 may be increased. According to the type and / or content of the pH adjusting agent added to the source solution 10, the graphene oxide 3, the oxidizing agent 5, and the pH adjusting agent 7 in the solvent 8 react. The pH environment can be controlled. The pH regulator (7) reacts with the oxidant (5) as the basicity of the pH regulator added to the source solution (10) is higher or the content of the pH regulator added to the source solution (10) increases. The amount of hydroxide ions (OH-) provided from) may be increased, thereby increasing the amount of · OH radicals that are reaction products of the oxidant (5) and the pH adjuster (7). Accordingly, the number of the pores 4 in the graphene oxide 3 may be increased, so that the porosity of the graphene oxide 3 in the form of the sheet may be increased.

According to one embodiment, the pH of the source solution 10 may be 5 to 12. If the pH of the source solution 10 is 13 or more, as described above, the graphene oxide of the OH radical which oxidizes the graphene oxide 3 to form the pores 4 in the graphene oxide 3. Access to the fins 3 is limited, so that the reaction efficiency for the reaction forming the voids 4 in the graphene oxide 3 can be reduced. In addition, the graphene oxide 3 may be aggregated and precipitated in the source solution 10.

According to one embodiment, the higher the reaction temperature of the graphene oxide (3), the oxidizing agent (5), and the pH adjuster (7) in the solvent (8), the higher the porosity of the graphene oxide (3) Can be. In other words, the higher the reaction temperature, the more the reaction mechanism disclosed in [Formula 1] and [Formula 2], which promotes the production of · OH radicals that form the pores 4 in the graphene oxide 3. Can be. Accordingly, the number of the pores 4 in the graphene oxide 3 may be increased, so that the porosity of the graphene oxide 3 in the form of the sheet may be increased.

According to an embodiment, the reaction temperature may be room temperature (25 ° C.) to 250 ° C. The voids 4 may be formed in the graphene oxide 3 without accompanying a reduction reaction of the graphene oxide 3 in a room temperature environment. Accordingly, the process required for the composition of the high temperature environment can be simplified, the process cost can be reduced, and the graphene oxide 3 having the voids 4 having excellent dispersibility can be provided.

As described above, graphene oxide dispersed in the source solution 10 is adjusted by adjusting the content of the oxidant 5 in the source solution 10, the pH of the source solution 10, and the reaction temperature. The porosity of (3) can be easily adjusted. The porosity of the graphene oxide 3 is an important factor controlling the electrical, thermal, optical, and mechanical properties of the graphene oxide 3. Accordingly, according to an embodiment of the present invention, without the use of a catalyst or the inflow of external energy, in a simple way to adjust the content of the materials used in the preparation of the source solution 10, and / or temperature conditions, By adjusting the porosity of the pin 3, it is possible to easily control the electrical, thermal, optical, and mechanical properties of the graphene oxide (3).

In addition, in the step of preparing the source solution 10, since the pores 4 are formed in the graphene oxide 3 without accompanying the reduction reaction of the graphene oxide 3, the pores 4 are Like the graphene oxide 3 not formed, the graphene oxide 3 can maintain high dispersibility in the source solution 10. Due to the high dispersibility of the graphene oxide 3 in the source solution 10, subsequent processes such as functionalization, complexation, and doping with the graphene oxide 3 are possible, and have liquid crystal properties. Can be. Accordingly, by controlling the porosity of the graphene oxide (3) by the method described above, by performing the subsequent process for the graphene oxide (3), it is easy to control the physical properties of the graphene oxide (3), The physical properties of the graphene oxide 3 can be effectively improved.

According to one embodiment, after preparing the source solution 10 having the voids 4, the unreacted material in the source solution 10 may be removed. According to one embodiment, the unreacted material in the source solution 10 may include the oxidant (5), and the pH regulator (7) that does not participate in the reaction.

According to an embodiment, the graphene oxide 3 having the pores 4 dispersed in the source solution 10 may be obtained in the form of powder. According to one embodiment, the method for obtaining the graphene oxide 3 in which the pore 4 is formed in the powder form is not particularly limited. For example, in order to obtain graphene oxide 3 having the pore 4 in the form of powder, any one of dialysis membrane, centrifugation, phase separation, vacuum filter, or lyophilization may be used.

A method of preparing graphene fibers according to a third embodiment of the present invention will be described in detail using a source solution prepared by the method described with reference to FIGS. 7 to 10.

In describing the graphene fibers according to the third embodiment of the present invention, the description of the manufacturing method of the graphene fibers according to the first and second embodiments of the present invention shown in FIGS. For the part, reference is made to FIGS. 1 to 10.

Referring to FIG. 11, a source solution 10 in which graphene oxide 3 is dispersed may be prepared (S1000). Preparing the source solution 10 prepared with graphene oxide 3 may be the same as the method of preparing the source solution 10 described with reference to FIGS. 7 to 10.

According to an embodiment, the porosity in the graphene oxide 3 may be adjusted according to the content of the oxidant 5 in the source solution 10, the pH of the source solution 10, and the reaction temperature. have.

According to one embodiment, as the content of the oxidant (5) in the source solution 10 increases, the higher the pH of the source solution 10, the higher the reaction temperature, the graphene oxide (3) The porosity can be increased.

In addition, according to one embodiment, according to the concentration of the graphene oxide (3) in the source solution 10, the elongation of the graphene fibers to be described later can be adjusted. Specifically, according to the concentration of the graphene oxide (3) in the source solution 10, the degree of orientation and porosity of the graphene fibers are adjusted, the elongation of the graphene fibers can be easily adjusted.

According to one embodiment, as the concentration of the source solution 10 is increased, the degree of orientation of the graphene fibers is reduced, the porosity of the graphene fibers may be increased. Accordingly, as the concentration of the source solution 10 increases, the elongation rate of the graphene fibers may increase.

The source solution 10 may be spun into the base solution 20 including the dissimilar elements, and thus, the graphene oxide fiber 30 may be manufactured (S2000). According to one embodiment, the base solution 20 may be prepared by adding a salt containing the heterogeneous element to a solvent. According to one embodiment, the salt containing a heterogeneous element is a salt containing an element other than carbon (C), nitrogen (N) salt, sulfur (S) salt, fluorine (F) salt, or It may be any one of iodine (I) salts.

According to one embodiment, the base solution 20 may further include a coagulant. The graphene oxide fiber prepared by spinning the source solution 10 in the base solution 20 may be solidified by the coagulant included in the base solution 20.

As described with reference to FIG. 2, the source solution 10 contained in the first container 100 is connected to the base solution 20 through a spinneret 120 connected to the first container 100. It may be radiated to the second container 150 contained therein. In the process of spinning the source solution 10 into the base solution 20, by the solvent exchange phenomenon, the salt containing the heterogeneous element may be diffused into the graphene oxide fibers.

According to one embodiment, as the spinning speed of the source solution 10 decreases, the degree of orientation of the graphene fibers is reduced, the porosity of the graphene fibers may be increased. Accordingly, as the spinning speed of the source solution 10 decreases, the elongation of the graphene fibers may increase.

In addition, according to the type and / or content of the heterogeneous elements included in the base solution 20, the electrical conductivity of the graphene fibers can be adjusted. Specifically, the heterogeneous elements diffused into the graphene oxide fibers may be doped into the graphene fibers in the thermal treatment step of step S4000 described later. Accordingly, by controlling the type and / or content of the heterogeneous elements included in the base solution 20 in step S2000, the electrical conductivity of the graphene fibers can be easily adjusted.

By separating, washing, and drying the graphene oxide fibers from the base solution 20, the graphene oxide fibers 30 including the dissimilar elements may be obtained (S3000). The graphene oxide fibers may be separated from the second container 150 containing the base solution 20 by the guide rollers 170 and may come out to the outside. The graphene oxide fiber 30 including the heterogeneous element separated from the base solution 20 may include the coagulant.

According to one embodiment, in the step of obtaining the graphene oxide fiber 30 containing the dissimilar element, the graphene oxide fiber 30 including the dissimilar element is dried at the same time through the heating process, and wound up Can be. As can be seen in FIG. 2, after the washing process is finished, the graphene oxide fibers 30 including the heterogeneous elements may be wound by the winding roller 190 while the drying process is performed.

The dried graphene oxide fiber 30 including the heterogeneous element is heat-treated, and thus, the graphene fiber doped with the heterogeneous element may be manufactured (S4000). Specifically, through the heat treatment, the graphene oxide fiber of the graphene oxide fiber 30 including the dissimilar element is reduced to the graphene fiber, and the heterogeneous contained in the graphene oxide fiber 30 An element may be doped into the graphene oxide fiber 30.

As described above, according to the type and / or content of the heterogeneous element doped in the graphene oxide fiber 30, the electrical conductivity of the graphene fiber can be easily adjusted. According to one embodiment, the heterogeneous element, other than carbon (C), may be any one of nitrogen (N), sulfur (S), fluorine (F), or iodine (I).

In addition, as described with reference to Figures 7 to 11, due to the voids (4) formed in the graphene oxide fibers 30 containing the heterogeneous element according to an embodiment of the present invention, the subsequent process is A heat treatment process can be performed. Accordingly, the hetero element may be doped into the graphene oxide fiber. Accordingly, by the subsequent process, the graphene oxide fiber 30 including the dissimilar element is made of the graphene fiber, and the electrical and optical properties of the graphene fiber can be easily controlled.

The graphene fibers may react with the aqueous solution containing the first oxidizing agent to form fine pores in the graphene fibers (S5000). According to an embodiment, the first oxidant is the same as the oxidant 5 described with reference to FIGS. 1 to 4, and the oxidant 5 used in the preparation of the source solution 10 in step S1000. can do. According to one embodiment, the oxidant may be hydrogen peroxide (H ₂ O ₂ ).

According to one embodiment, in the subsequent process for the graphene fibers, after the graphene fibers are supported in an aqueous solution containing the first oxidizing agent, a hydrothermal reaction is performed, thereby adding the fine pores to the graphene fibers It can be formed as. The subsequent process for the graphene fibers may be performed, and due to the micropores additionally formed in the graphene fibers, electrical and optical properties of the graphene fibers may be improved.

According to one embodiment, the fine pores additionally formed in the graphene fibers, can be easily adjusted according to the amount of the first oxidant included in the aqueous solution and the temperature and / or time at which the hydrothermal reaction is performed. have.

As such, the subsequent process may be possible by the gap 4 formed in the graphene fiber according to the embodiment of the present invention. Accordingly, by the subsequent process of the graphene fiber, the electrical and optical properties of the graphene fiber can be easily adjusted.

According to one embodiment, the fine pores additionally formed on the graphene fibers, after supporting the graphene fibers in an aqueous solution of 1 to 35% hydrogen peroxide, at a temperature of 300 to 500 ℃ in a high pressure reactor, 10 minutes It can be formed by performing the hydrothermal reaction for 4 hours.

Unlike the above-described embodiment of the present invention, the graphene formed with conventional pores is manufactured by a dry process or a wet process. First, when preparing the graphene with the pores formed through the dry process, a high temperature reaction of 600 ° C. or higher is used under a metal (K, Fe, or Ni) catalyst. In this case, there is a problem that a heterogeneous reaction in which pores are formed only at the contact point of the metal catalyst and graphene oxide occurs. In addition, after completion of the reaction, a process cost is increased for the removal and recovery of the metal catalyst, and high energy is required to create a high temperature reaction environment.

In addition, when manufacturing the graphene formed the voids through the wet process, since the inflow of external energy such as strong acid and heat and / or UV is required, there is a problem that the process is complicated, the process cost increases.

In addition, when manufacturing the graphene with the voids using the dry process and the wet process, all or part of the graphene oxide is reduced due to the considerable amount of energy applied during the process, the graphene with the voids formed Can be obtained. In the case of the graphene oxide formed with a portion of the graphene oxide is reduced, the dispersibility is low tends to aggregate, there is a difficulty in controlling the physical properties of the graphene oxide through a subsequent process.

However, according to an embodiment of the present invention, after adding the graphene oxide (3), oxidizing agent (5), and pH adjusting agent (7) to the solvent (10), and reacted to the graphene oxide having a void (4) ( A source solution 10 in which 3) is dispersed can be provided.

First, graphene oxide 3 dispersed in the source solution 10 is controlled by adjusting the content of the oxidant 5 in the source solution 10, the pH of the source solution 10, and the reaction temperature. The porosity of can be easily adjusted. Accordingly, the porosity of the graphene oxide 3 can be adjusted in a simple way to adjust the content of the materials used in the preparation of the source solution 10, and / or the temperature conditions, without the use of a catalyst or the introduction of external energy. By adjusting, the electrical, thermal, optical, and mechanical properties of the graphene oxide 3 in the source solution 10 can be easily controlled.

In addition, as described above, the use of a simple solution process, which eliminates the use of catalysts and strong acids and proceeds in ambient conditions without the need for external energy inflow, reduces the cost of removing and recovering the catalysts and strong acids. As a result, the processing window is wide, and mass production of the graphene oxide 3 having the pores 4 is possible.

In addition, since the pores 4 are formed in the graphene oxide 3 without accompanying a reduction reaction, similar to the graphene oxide 3 in which the pores 4 are not formed, the source solution 10 It can have high dispersibility within. Due to the high dispersibility of the graphene oxide 3 in the source solution 10, subsequent processes such as functionalization, complexation, and doping with the graphene oxide 3 are possible, and have liquid crystal properties. Can be. Therefore, by adjusting the porosity of the graphene oxide 3 and performing the subsequent process on the graphene oxide 3 by the above-described method, the physical properties of the graphene oxide 3 can be easily controlled. In addition, the physical properties of the graphene oxide 3 can be effectively improved.

In addition, when manufacturing the graphene fiber, the concentration of the graphene oxide (3) in the source solution 10, the spinning speed of the source solution 10 to be emitted into the base solution 20, the heterogeneous element By adjusting the winding speed of the graphene oxide fiber 30 to be included, and / or the length of the drying table on which the graphene oxide fiber 30 including the heterogeneous element is disposed, the degree of orientation of the graphene fiber is easily adjusted. Can be.

In addition, by controlling the type and / or content of the heterogeneous element doped in the graphene fiber, the electrical conductivity of the graphene fiber can be easily adjusted. As such, the graphene fiber according to the embodiment of the present invention may be utilized in various fields requiring excellent electrical conductivity characteristics.

In addition, due to the voids formed in the graphene oxide fiber including the dissimilar element according to the embodiment of the present invention, the heat treatment process, which is the subsequent process, may be performed on the graphene oxide fiber including the dissimilar element. . Accordingly, the graphene oxide fibers are reduced to make the graphene fibers, and at the same time, the hetero elements are doped, so that the electrical and optical properties of the graphene fibers can be easily controlled.

In addition, the subsequent process may be further performed by the pores formed in the graphene fibers produced. Accordingly, through the subsequent process, the fine pores are additionally formed in the graphene fibers to effectively control the electrical and optical properties of the graphene fibers.

Hereinafter, the evaluation of the characteristics of the graphene fibers produced according to the embodiments of the present invention will be described.

First, the evaluation of the characteristics of the graphene fibers produced according to the first embodiment of the present invention will be described.

Graphene fiber manufacturing method according to the first embodiment

Graphene oxide was added to DI water, followed by stirring for 24 hours to prepare a source solution containing graphene oxide. Salts containing heterogeneous elements in an aqueous solution based on alcohol (ammonium chloride, ammonium sulfate, or ammonium phosphate) and coagulants (calcium chloride (CaCl ₂ ), potassium hydroxide (KOH), sodium hydroxide) (NaOH), sodium chloride (NaCl), copper sulfate (CuSO ₄ ), cetyltrimethylammonium bromide (CTAB), or chitosan) were added to prepare a base solution containing heterogeneous elements. Graphene oxide fibers were prepared by spinning the source solution into the base solution through a spinneret connected to the end of the first vessel containing the source solution. The graphene oxide fibers were separated from the base solution to prepare graphene oxide fibers including heterogeneous elements. After removing the coagulant remaining on the graphene oxide fiber containing the heterogeneous element using an alcoholic aqueous solution, it was dried by applying heat to the graphene oxide fiber containing the hetero element at a temperature of 70 to 80 ° C. through a heater. . Thereafter, the dried graphene oxide fiber including the heterogeneous element is heat-treated under an inert gas atmosphere (100 to 5000 ° C., 10 to 100 ° C./min, 10 min to 10 hrs), and thus the first element of the present invention doped with the hetero element. Graphene fiber according to the embodiment was prepared.

According to the method for producing graphene fibers according to the first embodiment, after preparing the source solution, the source solution to the base solution through the spinneret connected to the end of the first container containing the source solution Spinning, the process of producing the graphene oxide fiber was examined.

Referring to FIG. 12, it was confirmed that the graphene oxide fibers were prepared while the source solution was spun into the base solution through the spinneret. In the process of spinning the source solution into the base solution, it is determined that a salt containing the heterogeneous element contained in the base solution is diffused into the graphene oxide fiber by a solvent exchange phenomenon.

According to the graphene fiber manufacturing method according to the first embodiment, after the graphene oxide fiber comprising the heterogeneous element is manufactured, the process of winding the graphene oxide fiber comprising the heterogeneous element by the winding roller I looked at it.

Referring to FIG. 13, it was confirmed that the graphene oxide fiber including the heterogeneous element separated from the base solution was washed and then dried and wound by the winding roller. When the winding speed of the graphene oxide fiber containing the heterogeneous element is smaller than the spinning speed of the source solution, the porosity of the graphene fiber increases as the degree of orientation of the graphene fiber decreases, so that the graphene has excellent elongation. We believe it is possible to provide fin fibers.

According to the manufacturing method of the graphene fiber according to the first embodiment, in order to lower the degree of orientation of the graphene fiber, to lower the concentration of graphene oxide in the source solution, or to reduce the spinning speed of the source solution, The graphene fibers were prepared by slowing the winding speed of graphene oxide fibers including heterogeneous elements than the spinning speed of the source solution.

Referring to FIG. 14, in order to reduce the orientation of the graphene fibers, the graphene oxide fibers including the heterogeneous elements may be increased by increasing the concentration of graphene oxide in the source solution, decreasing the spinning speed of the source solution, or the like. When the graphene fiber is manufactured by slowing the winding speed of the source solution, the degree of orientation of the finally produced graphene fiber is low, and the porosity of the graphene fiber increases to increase the graphene fiber. It was confirmed that the pin fibers were produced.

According to the manufacturing method of the graphene fiber according to the first embodiment, to increase the degree of orientation of the graphene fiber, to lower the concentration of graphene oxide in the source solution, to increase the spinning rate of the source solution, The graphene fibers were manufactured by winding the graphene oxide fibers including heterogeneous elements faster than the spinning rate of the source solution.

Referring to FIG. 15, in order to increase the degree of orientation of the graphene fibers, the concentration of graphene oxide in the source solution may be decreased, the spinning speed of the source solution may be increased, or the graphene oxide fibers including the heterogeneous elements may be used. When the graphene fibers are manufactured by making the winding speed of the source solution faster than the spinning speed of the source solution, the degree of orientation of the finally produced graphene fibers is high, and the porosity of the graphene fibers is reduced, thereby reducing the elongation. It was confirmed that the pin fibers were produced.

From the results of FIGS. 14 and 15, in the preparation of the graphene fibers, the concentration of graphene oxide in the source solution used, the spinning rate of the source solution spun into the base solution, and the graphene oxide including the heterogeneous elements By adjusting the winding speed of the pin fibers and / or the length of the drying stand on which the graphene oxide fibers including the dissimilar elements are disposed, the degree of orientation of the graphene fibers can be easily adjusted. Accordingly, it was found that the graphene fiber 70 can be easily manufactured by controlling the elongation rate by an easy method such as concentration and spinning speed according to the electrical and physical properties of the application field.

In the same manner described with reference to FIG. 16, the graphene fibers having low and high orientations were prepared. For the graphene fibers with low and high orientations, the change in magnitude of the external pressure exerted until the graphene fibers broke was measured.

Referring to FIG. 16, the tensile strength value required to break the graphene fiber with high orientation is about 2%, and the tensile strength value required to break the graphene fiber with low orientation is about 15%. It confirmed that it was%. From this, it was found that the graphene fiber having a low degree of orientation has a better elongation than the graphene fiber having a high degree of orientation. This is because the porosity of the graphene fiber having a low degree of orientation is larger than that of the graphene fiber having a high degree of orientation, so that the graphene fiber having a low degree of orientation is more flexible than the graphene fiber having a high degree of orientation. Judging by the result of having

Next, the evaluation of the characteristics of the graphene fibers produced of the graphene fibers prepared according to the second embodiment of the present invention will be described.

Graphene fiber production according to the second embodiment 1

The graphene oxide sheet was dispersed in DI water to prepare a source solution in which the graphene oxide sheet was dispersed, and a coagulation bath including 4.5 wt% CaCl ₂ as a binder and 0.5 wt% KOH as a reducing agent was prepared. Graphene oxide fibers were prepared by spinning the source solution into the coagulation bath through a 400 μm spinneret. The graphene oxide fibers were coagulated in a coagulation bath, then dried and washed with ethanol solution and dried in an oven to remove the remaining coagulation bath.

Subsequently, the dried graphene oxide fibers were immersed in an iodinated aqueous solution, reduced at a temperature of 70 to 80 ° C., washed with ethanol, and dried to prepare graphene fibers according to Example 1.

Graphene fiber preparation according to Comparative Example 1

Graphene fibers were prepared under the same process conditions as in Example 1, but using a coagulation bath containing 5 wt% of CaCl ₂ , graphene fibers according to Comparative Example 1 were prepared.

Graphene fiber preparation according to Comparative Example 2

* Graphene fibers were prepared under the same process conditions as in Example 1, but using a coagulation bath containing 5 wt% of KOH, graphene fibers according to Comparative Example 2 were prepared.

17 is a photograph taken of the graphene fibers according to the second embodiment 1, comparative example 1, and comparative example 2 of the present invention, Figure 18 is a second embodiment 1, comparative example 1, and comparative example of the present invention It is a graph measuring the circularity of graphene fibers according to 2.

Referring to FIG. 17, (a), (b), and (c) of FIG. 17 are photographs of graphene fibers according to Comparative Example 1, Second Example 1, and Comparative Example 2, respectively. As can be seen in Figure 17, in the case of the graphene fiber according to Example 1 prepared using a coagulation bath containing CaCl ₂ and KOH at the same time, using a coagulation bath containing any one of CaCl ₂ and KOH Compared with the graphene fibers prepared according to Comparative Example 1 and Comparative Example 2, it can be seen that the cross section is significantly close to the circular.

In addition, referring to Figure 18, the circularity value of the graphene fibers according to Comparative Example 1 and Comparative Example 2 prepared using a coagulation bath containing any one of CaCl ₂ and KOH according to [Equation 1 below] Calculated.

[Equation 1]

Roundness = 4πA / (P ² ) (A: cross section, P: circumference)

In the case of the graphene fibers prepared according to Comparative Example 1 and Comparative Example 2 prepared using a coagulation bath containing any one of CaCl ₂ and KOH, the circularity value is large, as well as containing both CaCl ₂ and KOH simultaneously Compared with the graphene fibers according to Example 1 prepared using the coagulation bath, it can be seen that the circularity value is significantly lower.

In addition, in the case of the graphene fiber according to the first embodiment, it can be confirmed that the circularity value has a significantly lower deviation, as well as a circularity value of 0.8 or more. In other words, it can be confirmed that manufacturing graphene fibers using a coagulation bath including a binder and a reducing agent at the same time is an effective method for producing graphene fibers having a plateau shape of 0.8 or more.

19 is a photograph of the surface of the graphene fiber according to the second embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention, Figure 20 is a second embodiment 1, Comparative Example 1, and It is a graph which measured the standard deviation of the thickness of the graphene fiber by the comparative example 2.

19, (a), (b), and (c) of FIG. 19 are photographs photographing surfaces of graphene fibers according to Comparative Example 1, Second Example 1, and Comparative Example 2, respectively. As can be seen in Figure 19, in the case of the graphene fiber according to the second embodiment 1 prepared using a coagulation bath containing CaCl ₂ and KOH at the same time, using a coagulation bath containing any one of CaCl ₂ and KOH Compared with the graphene fibers prepared according to Comparative Example 1 and Comparative Example 2, it can be seen that the uniformity of the thickness is significantly high.

Also, Referring to Figure 20, in the case of CaCl ₂ and a fiber graphene in accordance with the Comparative Examples 1 and 2 prepared using a coagulation bath containing any one of KOH, CaCl _2, and a coagulation bath containing KOH at the same time It can be seen that the standard deviation value of the thickness is remarkably high as compared with the graphene fiber according to the second embodiment 1 manufactured by using.

In other words, it can be seen that manufacturing graphene fibers using a coagulation bath containing a binder and a reducing agent at the same time is an effective method for producing graphene fibers having a substantially uniform thickness.

Graphene fiber production according to the second embodiment 2

The graphene oxide sheet was dispersed in DI water to prepare a source solution in which 1.0 mg / ml of the graphene oxide sheet was dispersed, and a coagulation bath including CoCl ₂ as a binder and KOH as a reducing agent was prepared. Graphene oxide fibers were prepared by spinning the source solution into the coagulation bath through a 400 μm spinneret. The graphene oxide fibers were coagulated in a coagulation bath, then dried and washed with ethanol solution and dried in an oven to remove the remaining coagulation bath.

Subsequently, the dried graphene oxide fibers were immersed in an iodide aqueous solution, reduced at a temperature of 70 to 80 ° C., washed with ethanol and dried to prepare graphene fibers according to Example 2.

Graphene fiber production according to the second embodiment 3

Graphene fibers were prepared under the same process conditions as in Example 2, but the graphene fibers according to Example 3 were prepared using a coagulation bath containing AlCl ₃ as a binder and KOH as a reducing agent.

Graphene fiber production according to the second embodiment 4

Graphene fibers were prepared under the same process conditions as in Example 2, but using a coagulation bath containing FeCl ₃ as a binder and KOH as a reducing agent, graphene fibers according to Example 4 were prepared.

FIG. 21 is an AFM image of a graphene oxide sheet used to prepare graphene fibers according to Examples 2 to 4 of the present invention, and FIG. 22 is a graphene fibers according to Examples 2 to 4 of the present invention. The source solution used in the preparation and the photograph taken after the addition of CoCl ₂ , AlCl ₃ , and FeCl ₃ , respectively.

Referring to FIGS. 21 and 22, the AFM topology and thickness of the graphene oxide sheets used in Examples 2 to 4 were measured. The thickness of the graphene oxide sheet was measured to be about 1.2 nm.

In addition, the source solution prepared by dispersing the graphene oxide sheet in DI water by mild sonication, CoCl ₂ , AlCl ₃ , and FeCl ₃ were added to the source solution, respectively, and photographed.

23 is a photograph taken for measuring the viscosity after the addition of CoCl ₂ , AlCl ₃ , and FeCl ₃ to the source solution used in the preparation of graphene fibers according to Examples 2 to 4 of the present invention, 24 is a graph measuring the viscosity of a sauce solution used in the preparation of graphene fibers according to Examples 2 to 4 of the present invention and a solution in which CoCl ₂ , AlCl ₃ , and FeCl ₃ are added thereto, respectively, 25 is a storage modulus of the source solution used in the preparation of the graphene fibers according to the second embodiment 2 to 4 of the present invention and the solution to which CoCl ₂ , AlCl ₃ , and FeCl ₃ are added thereto, respectively, 26 is a graph showing the degree of gelation of the source solution used in the preparation of the graphene fibers according to the second embodiment 2 to 4 of the present invention and a solution in which CoCl ₂ , AlCl ₃ , and FeCl ₃ were added thereto, respectively. to be.

Referring to FIG. 23, when the source solution used in Examples 2 to 4 is turned over, it can be seen that most of the source solution flows down due to the low viscosity. In addition, even when LiCl containing a monovalent metal is added to the source solution, it can be seen that most of the source solution flows down due to the low viscosity.

On the other hand, in the case of a solution in which CoCl ₂ , AlCl ₃ , and FeCl ₃ are added to the source solution, respectively, the viscosity increases, and even if the container is turned over, the solution is gelled by CoCl ₂ , AlCl ₃ , and FeCl ₃ , It can be seen that a large amount of solution remains at the top of the vessel.

In addition, referring to FIGS. 24 to 26, in the case of the solution in which CoCl ₂ , AlCl ₃ , and FeCl ₃ are added to the source solution, respectively, it can be seen that the viscosity is significantly increased and the storage modulus is significantly increased. . In addition, when AlCl ₃ and FeCl ₃ containing a _trivalent metal were added, it was confirmed that the viscosity and storage modulus were remarkably high, compared to the addition of CoCl ₂ containing a _divalent metal.

In other words, when a binder containing divalent or trivalent metal ions such as CoCl ₂ , AlCl ₃ , and FeCl _{3 is} added to the source solution in which the graphene oxide sheet is dispersed, as described with reference to FIG. 4. , Oxygen of the graphene oxide sheet and divalent or trivalent metal ions are bonded, it can be seen that the bond between the graphene oxide sheet is strengthened. That is, as shown in Figure 26, it can be seen that the gelation of the source solution is in progress.

Thus, the graphene oxide fiber is produced by spinning the source solution in which the graphene oxide sheet is dispersed in a coagulation bath having a binder containing divalent or trivalent metal ions such as CoCl ₂ , AlCl ₃ , and FeCl _3. In this case, it can be seen that the mechanical strength of the graphene oxide fiber is improved.

FIG. 27 is a graph of XRD measurement of graphene oxide fibers according to Examples 2 to 4 of the present invention, and FIG. 28 is a graph illustrating mechanical strength of graphene oxide fibers according to Examples 2 to 4 of the present invention. 29 is a graph illustrating a graphene oxide fiber according to a second exemplary embodiment of the present invention.

Referring to FIG. 27, XRDs of the graphene oxide fibers according to Examples 2 to 4 were measured. As shown in FIG. 27, when the source solution was spun into a coagulation bath containing no binders such as CoCl ₂ , AlCl ₃ , and FeCl ₃ to prepare graphene oxide fibers (pristine GO fibers), graphene oxide The d spacing of the graphene oxide sheet in the fiber was measured to be about 8.08 kPa. In addition, when the graphene oxide fibers were prepared by spinning the source solution in a coagulation bath including CoCl ₂ , AlCl ₃ , and FeCl ₃ binder, d spacing was measured to be 8.79 kV, 9.01 kPa, and 9.51 kPa, respectively. That is, it can be seen that the d spacing of the graphene oxide sheet in the graphene oxide fiber increases according to the valent number of the cation.

In addition, referring to FIG. 28, the mechanical strength of the graphene oxide fibers according to Examples 2 to 4 was measured. The source solution was spun onto a coagulation bath containing no binders such as CoCl ₂ , AlCl ₃ , and FeCl ₃ to convert the graphene oxide fibers (pristine GO fiber), the source solution into CoCl ₂ , AlCl ₃ , and FeCl ₃ binders. The mechanical strength of the graphene oxide fibers by spinning in a coagulation bath may be summarized as shown in Table 1 below.

구분division	Strength(MPa)Strength (MPa)	Stiffness(GPa)Stiffness (GPa)	Elongation at break (%)Elongation at break (%)
pristine GO fiberpristine GO fiber	--	--	--
제2 실시 예 2 Second Embodiment 2	407.24407.24	75.475.4	0.650.65
제2 실시 예 3 Second Embodiment 3	464.16464.16	88.188.1	0.620.62
제2 실시 예 4 Second Embodiment 4	510.53510.53	107.0107.0	0.580.58

The source solution was spun into a coagulation bath containing no binders such as CoCl ₂ , AlCl ₃ , and FeCl ₃ to the extent that strength, stiffness, and elongation at break could not be measured in the case of pristine GO fibers. The mechanical properties were found to be weak.

On the other hand, in the case of the graphene oxide fibers according to the second embodiment 2 to 4 has a high mechanical strength, and also as the ionic value of the metal ions used as the binder increases, the strength and stiffness value increases As a result, the Elongation at break value decreases.

In other words, it can be seen that by using a coagulation bath containing no binder such as CoCl ₂ , AlCl ₃ , and FeCl ₃ , the mechanical properties of the spun graphene oxide fibers can be improved.

Referring to FIG. 29, the graphene oxide fibers according to the second example 2 were bent. As shown in FIG. 29, it is confirmed that graphene oxide sheets are bonded by Co ions and have high flexibility.

Finally, characteristic evaluation of the graphene fibers produced according to the third embodiment of the present invention is described.

Method for producing a sauce solution according to the third embodiment

0.01 to 10 wt% graphene oxide, 0.1 to 40 wt% oxidant hydrogen peroxide (H ₂ O ₂ ) aqueous solution, and pH adjuster (LiOH, NaOH, KOH, NH ₄ OH, Ca (OH) ₂ , Sr (OH) ₂ , CsOH, Ba (OH) ₂ , Mg (OH) ₂ , Cd (OH) ₂ , La (OH) ₃ , In (OH) ₃ , Nd (OH) ₃ , Gd (OH) ₃ , FeOOH, RbOH, Al (OH) ₃ , Ni (OH) ₂ , NaF, K ₂ Co ₃ , or NH ₄ ClO) was added to DI water as a solvent, and then reacted at room temperature (25 ° C.) to prepare a source solution.

Method for producing a sauce solution according to a comparative example of the third embodiment

The source solution solution is prepared in the same manner as the method for preparing the source solution according to the third embodiment, wherein the weight of the hydrogen peroxide as the oxidizing agent is 40 wt% or more, and the pH adjusting agent is adjusted so that the pH of the source solution is 13 or more. Excess was added to prepare a sauce solution according to the comparative example.

Graphene fiber manufacturing method according to the third embodiment

According to the method of preparing the source solution according to the third embodiment, the source solution in which the graphene oxide with pores was dispersed was prepared. Salts containing dissimilar elements in an alcoholic aqueous solution (ammonium chloride, ammonium sulfate, or ammonium phosphate) and coagulants (calcium chloride (CaCl ₂ ), potassium hydroxide (KOH), sodium hydroxide) (NaOH), sodium chloride (NaCl), copper sulfate (CuSO ₄ ), cetyltrimethylammonium bromide (CTAB), or chitosan) were added to prepare a base solution containing heterogeneous elements. Graphene oxide fibers were prepared by spinning the source solution into the base solution through a spinneret connected to the end of the first vessel containing the source solution. The graphene oxide fibers were separated from the base solution to prepare graphene oxide fibers including heterogeneous elements. After removing the coagulant remaining on the graphene oxide fiber containing the heterogeneous element using an alcoholic aqueous solution, it was dried by applying heat to the graphene oxide fiber containing the hetero element at a temperature of 70 to 80 ° C. through a heater. . Thereafter, the dried graphene oxide fiber including the heterogeneous element is heat-treated (100 to 5000 ° C., 10 to 100 ° C./min, 10 min to 10 hrs) under an inert gas atmosphere, and the third element of the present invention is doped with the hetero element. Graphene fiber according to the embodiment was prepared.

30 is an SEM image of graphene oxide with pores formed in accordance with a third embodiment of the present invention. Specifically, (a) of FIG. 30 is an SEM image of graphene oxide in which pores dispersed in a source solution according to a third embodiment of the present invention, and FIG. 30 (b) is shown in FIG. 30 (a). SEM image of high magnification for graphene oxide according to a third embodiment of the present invention.

The source solution was prepared in the same manner as the method disclosed in the graphene fiber manufacturing method according to the third embodiment. Using an SEM (Scanning Electron Microscope) instrument, a detailed image of the surface of the graphene oxide dispersed in the source solution prepared according to the third embodiment of the present invention was measured.

Referring to (a) and (b) of FIG. 30, it was confirmed that the graphene oxide in the source solution according to the third embodiment of the present invention has a porous structure including pores. In the preparation of the source solution, it is determined that pores are formed in the graphene oxide by the · OH radical generated by the added hydrogen peroxide, the oxidizing agent.

After the source solution was prepared according to the method for preparing the source solution according to the third embodiment, the dispersion characteristics of graphene oxide in the source solution according to the third embodiment of the present invention were observed.

Referring to FIG. 31, it was confirmed that graphene oxide in the source solution did not aggregate and was stably dispersed. According to a third embodiment of the present invention, when the source solution is prepared, an appropriate amount of the oxidizing agent and the pH adjusting agent are used, so that the reaction between the graphene oxide, the oxidizing agent, and the pH adjusting agent occurs uniformly. Judging by the result.

According to the preparation method of the source solution according to the comparative example, after preparing the source solution using the excess of the oxidizing agent and the pH adjusting agent, the graphene oxide in the source solution according to the comparative example of the third embodiment of the present invention The dispersion characteristic of was observed.

Referring to FIG. 32, it was confirmed that graphene oxide in the source solution was aggregated to cause precipitation. Unlike the third embodiment of the present invention, when the source solution is prepared, an excessive amount of the oxidizing agent (> 40wt%) and the pH adjusting agent (> pH 13) is used, and it is determined that graphene oxide is aggregated. . Accordingly, it was found that the access of the OH radicals generated by the hydrogen peroxide as the oxidant to the aggregated graphene oxide was restricted, so that the reaction between the graphene oxide, the oxidant, and the pH regulator did not occur uniformly.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

Graphene fiber according to an embodiment of the present invention can be widely used in a variety of devices and devices, such as flexible devices, fibrous electronics, wires, capacitors.

Claims

Preparing a source solution containing graphene oxide;

Spinning the source solution with a base solution containing heterogeneous elements to produce graphene oxide fibers;

Separating, washing, and drying the graphene fibers from the base solution to obtain graphene oxide fibers including the heterogeneous elements; And

Comprising the step of thermally treating the graphene oxide fibers comprising the heterogeneous element (dry), the graphene fibers doped with the hetero element,

The elongation percentage of the graphene fiber is adjusted according to the concentration and spinning rate of the source solution.
According to claim 1,

As the concentration of graphene oxide in the source solution increases, the method for producing graphene fibers comprising the elongation of the graphene fibers increases.
According to claim 1,

As the spinning speed of the source solution is reduced, the method for producing graphene fibers comprising the elongation of the graphene fibers increases.
According to claim 1,

In the step of obtaining the graphene oxide fiber comprising the dissimilar element, drying the graphene oxide fiber comprising the dissimilar element, at the same time, the method of producing a graphene fiber further comprising the step of winding up.
The method of claim 4, wherein

When the spinning speed of the source solution is greater than the winding speed of the graphene oxide fiber containing the heterogeneous element, the graphene fiber manufacturing method comprising the increase in the elongation of the graphene fiber.
According to claim 1,

Preparing the graphene fibers,

The graphene oxide fiber is reduced to the graphene fiber through the heat treatment, and at the same time, the dissimilar elements included in the graphene oxide fiber are doped in the graphene oxide fiber. Way.
Preparing a source solution in which a graphene oxide sheet is dispersed;

Spinning the source solution into a coagulation bath comprising a reducing agent that partially reduces the graphene oxide sheet and a binder that binds the graphene oxide sheets, thereby spinning graphene oxide fibers Obtaining; And

Reducing the graphene oxide fibers, a graphene fiber manufacturing method comprising the step of producing a graphene fiber.
The method of claim 7, wherein

By the reducing agent, the graphene oxide sheet is partially reduced, thereby producing a partially reduced graphene oxide sheet,

And pi-pie stacking between the partially reduced graphene oxide sheets, thereby increasing the tensile strength of the graphene oxide fibers.
The method of claim 7, wherein

The binder is a method for producing graphene fibers containing divalent or trivalent metal ions.
The method of claim 7, wherein

Copper-plating the graphene fibers, a method for producing graphene fibers further comprising the step of producing a copper-plated graphene fibers.
The method of claim 10,

Preparing the copper plated graphene fiber,

Etching the graphene fibers;

Bonding a catalytic metal to the etched graphene fibers; And

Preparation of graphene fibers comprising the step of immersing the graphene fibers bonded to the catalyst metal in a solution containing copper, and reducing the copper using the catalyst metal, plating the graphene fibers with copper. Way.
The method of claim 10,

The copper plated graphene fiber,

The graphene oxide sheet is a method for producing graphene fibers comprising pores provided between the reduced graphene sheets, or a copper structure provided on the surface of the graphene fibers.
The method of claim 7, wherein

Preparing the graphene fibers,

Drying the graphene oxide fibers;

Washing and drying the dried graphene oxide fibers; And

The method of manufacturing a graphene fiber comprising the step of reducing the graphene oxide fibers by a method of heat-treating the washed and dried graphene oxide fibers in a reducing solution.
The method of claim 7, wherein

The source solution further comprises carbon nanotubes,

The graphene fiber, the graphene fiber manufacturing method further comprising the carbon nanotubes.
Adding graphene oxide, an oxidizing agent, and a pH adjusting agent to a solvent, and then reacting to prepare a source solution in which graphene oxide having pores is dispersed;

Spinning the source solution with a source solution containing heterogeneous elements to produce graphene oxide fibers;

Separating, washing, and drying the graphene oxide fibers from the source solution to obtain graphene oxide fibers including the dissimilar elements;

Thermally treating the dried graphene oxide fiber including the dissimilar element to produce graphene fibers doped with the dissimilar element; And

Reacting the graphene fibers with an aqueous solution containing a first oxidizing agent, to form a fine void in the graphene fibers manufacturing method of graphene fibers.
The method of claim 15,

And increasing the porosity of graphene oxide as the content of the oxidant in the source solution increases.
The method of claim 15,

The higher the pH of the source solution, the method of producing a graphene oxide source solution comprising increasing the porosity of graphene oxide.
The method of claim 15,

According to the content of the first oxidizing agent in the aqueous solution and the temperature and time of the reaction, the porosity of the fine pores formed in the graphene fibers is controlled graphene fiber manufacturing method.
The method of claim 15,

The porosity in the graphene oxide in the source solution is adjusted according to the content of the oxidant in the source solution, the pH of the source solution, and the reaction temperature.
The method of claim 15,

Preparing the graphene fibers,

At the same time as the graphene oxide fiber is reduced to the graphene fiber through the heat treatment, the heterogeneous element included in the graphene oxide fiber is doped (dope) to the graphene oxide fiber,

According to the content of the dissimilar element doped in the graphene oxide fiber, the graphene fiber manufacturing method comprising the electrical conductivity of the graphene fiber is adjusted.