KR20210112136A - Method of controlling the functional groups on the surface of the maxine particle to improve the stability to maxine oxidation - Google Patents

Abstract

An embodiment of the present invention provides a technique for remarkably improving the oxidation stability of MXene (Ti_3C_2) by minimizing a phenomenon that the MXene is easily oxidized. A method for improving oxidation stability of MXene through surface functional group control according to an embodiment of the present invention includes: a first step of introducing an amine solution into a MXene aqueous solution; and a second step of binding an amine ligand to the particle surface of the MXene by stirring the MXene aqueous solution and the amine solution to form a mixed solution.

Description

Method of improving oxidative stability of maxine by controlling surface functional groups

The present invention relates to a method for improving the oxidation stability of maxine by controlling surface functional groups, and more particularly, to a technology for remarkably improving the oxidation stability of _{maxine by minimizing the phenomenon of easily oxidizing maxine (MXene, Ti 3} C _{2 )} it's about

The two-dimensional material refers to a single-layer or few-layer solid in which atoms form a predetermined crystal structure. One of them, the MAX phase (where M is a transition metal, A is a group 13 or 14 element, and X is carbon and/or nitrogen) is a combination of MX with quasi-ceramic properties and a metal element A different from M. It has excellent physical properties such as electrical conductivity, oxidation resistance, and machinability. It is known that more than 60 types of MAX phases have been synthesized so far. The MAX phase is a two-dimensional material, but unlike graphite or metal dichalcogenide materials, transition metal carbides are stacked between each other's layers by a weak chemical bond between element A and transition metal M. Therefore, it is difficult to transform into a two-dimensional structure using a general mechanical peeling method or a chemical peeling method.

However, in 2011, a research team led by Professor Michel W. Barsoum of Drexel University selectively removed the aluminum layer using hydrofluoric acid (HF) from three-dimensional titanium-aluminum carbide, which is the MAX phase, by using a two-dimensional sphere with completely different properties. It succeeded in transforming into Joe. The research team named the two-dimensional material obtained by exfoliating the MAX phase "MXene". The maxine has similar electrical conductivity and strength to that of graphene, and can be applied to various application technologies ranging from energy storage devices to biomedical applications and composites.

This maxin is a short surface functional group, for example, an alkoxy group (-O), a hydroxyl group (-OH) and a fluoro group (- It contains F) and is characterized by being well dispersed in polar solvents such as water.

However, when maxin is dispersed in water and used, there is a problem in that it is easily oxidized by water. Specifically, when maxine (Ti ₃ C ₂ ) is stored in an aqueous solution, it is oxidized much faster by water _{and changed to TiO 2} , so there is a problem in that the oxidative stability of maxine is significantly reduced.

In Korean Patent Laid-Open Patent No. 10-2019-0135324 (Title of the Invention: Low-temperature storage method of maxine), (a) preparing a maxin solution composed of a transition metal carbide and a transition metal carbonitride having a two-dimensional structure, (b) Putting the prepared maxin solution in a container, (c) rapidly cooling the maxine solution contained in the container so that the electrical properties are kept constant, and by rapidly cooling the maxine and storing it in a low temperature state, the electrical characteristics of the maxine A storage method capable of maintaining a constant is disclosed.

Republic of Korea Patent Publication No. 10-2019-0135324

An object of the present invention for solving the above problems is _{to improve the oxidation stability of maxine (MXene, Ti 3} C ₂ ) because it is too easily oxidized and thus difficult to commercialize.

And, it is an object of the present invention, so that the process for improving the oxidative stability of the maxine is performed simply and at a low cost.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. There will be.

The configuration of the present invention for achieving the above object is a first step of introducing an amine solution into an aqueous solution of maxine (MXene); a second step of binding the amine ligand to the particle surface of the maxine by stirring the maxine aqueous solution and the amine solution to form a mixed solution; and a third step of separating the amine ligand from the maxine and redispersing the maxine in a polar solvent; and, characterized in that the oxidative stability of the maxine is improved by the amine ligand.

In an embodiment of the present invention, in the third step, a solution for dissolving an amine ligand is added to the mixed solution containing the amine-treated maxin and centrifuged to precipitate maxine, maxine A step 3-2 of discharging a solution in which the separated amine ligand is dissolved, and a step 3-3 of redispersing the precipitated maxine in a polar solvent may include.

In an embodiment of the present invention, the solution may be isopropyl alcohol (Isopropyl alcohol).

In an embodiment of the present invention, steps 3-1 to 3-3 may be performed a plurality of times.

In an embodiment of the present invention, by performing the steps 3-1 to 3-3 a plurality of times, the electrical resistance of the maxine film, which is a film formed using the maxim, may be reduced.

In an embodiment of the present invention, the amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline can be

In an embodiment of the present invention, in the second step, maxin may be stored for a predetermined time in a state in which it is bound to an amine ligand.

The configuration of the present invention for achieving the above object is a first step of precipitating maxine by centrifuging an aqueous solution of maxine (MXene); a second step of stirring the precipitated maxine and an amine solution to disperse the maxine in the amine solution, and binding an amine ligand to the particle surface of the maxine; A third step of precipitating the amine-treated maxine by centrifuging the amine solution in which the maxine is dispersed; A fourth step of dispersing the amine-treated maxine in water to form an amine-treated maxine aqueous solution; and a fifth step of separating the amine ligand from the maxine and redispersing the maxine in a polar solvent, wherein the oxidative stability of the maxine is improved by the amine ligand.

In an embodiment of the present invention, in the fifth step, a solution for dissolving an amine ligand is added to the amine-treated aqueous solution of maxine, and centrifugation is performed to precipitate maxine, step 5-1, separated from maxine A step 5-2 of discharging the solution in which the amine ligand is dissolved, and a step 5-3 of redispersing the precipitated maxine in a polar solvent may include.

In an embodiment of the present invention, the solution may be isopropyl alcohol (Isopropyl alcohol).

In an embodiment of the present invention, steps 5-1 to 5-3 may be performed a plurality of times.

In an embodiment of the present invention, by performing the steps 5-1 to 5-3 a plurality of times, the electrical resistance of the maxine film, which is a film formed using maxim, may be reduced.

In an embodiment of the present invention, the amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline can be

In an embodiment of the present invention, in the fourth step, maxine may be stored for a predetermined time in a state in which it is bound to an amine ligand.

The configuration of the present invention for achieving the above object is a first step of precipitating maxine by centrifuging an aqueous solution of maxine (MXene); a second step of stirring the precipitated maxine and an amine solution to disperse the maxine in the amine solution, and binding an amine ligand to the particle surface of the maxine; A third step of precipitating the amine-treated maxine by centrifuging the amine solution in which the maxine is dispersed; a fourth step of dispersing the amine-treated maxine in an organic solvent to form an organic solution in which the amine-treated maxine is dispersed; and a fifth step of separating the amine ligand from the maxine and redispersing the maxine in an organic solvent, wherein the oxidative stability of the maxine is improved by the amine ligand.

In an embodiment of the present invention, in the fourth step, the organic solvent may be the amine solution.

In an embodiment of the present invention, the fifth step is the fifth step of precipitating maxine by adding a solution for dissolving amine in an organic solvent in which the amine-treated maxin is dispersed and performing centrifugation to precipitate maxine, maxine A step 5-2 of discharging a solution in which the separated amine ligand is dissolved, and a step 5-3 of redispersing the precipitated maxine in a polar solvent, may include.

In an embodiment of the present invention, the solution may be isopropyl alcohol (Isopropyl alcohol).

In an embodiment of the present invention, steps 5-1 to 5-3 may be performed a plurality of times.

In an embodiment of the present invention, by performing the steps 5-1 to 5-3 a plurality of times, the electrical resistance of the maxine film, which is a film formed using maxim, may be reduced.

In an embodiment of the present invention, the amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline can be

In an embodiment of the present invention, in the fourth step, maxine may be stored for a predetermined time in a state in which it is bound to an amine ligand.

The effect of the present invention according to the above configuration is that, by binding an amine ligand to the particle surface of the maxine, and storing the amine-treated maxine in an aqueous solution or the like, the oxidative stability of the maxine can be significantly improved.

And, the effect of the present invention is that, in order to improve the oxidation stability of maxine, an amine solution is used and only processes such as mixing and precipitation are performed, and separate equipment such as low-temperature refrigeration is not used, so that the process is simple and the cost is low. will be.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is an image of the change over time of an aqueous solution of maxine not treated with amine according to an embodiment of the present invention.
Each of FIGS. 2 to 17 is an image of the time-dependent change of each mixed solution after stirring each different amine solution in the maxine aqueous solution according to an embodiment of the present invention.
Each of FIGS. 18 to 21 is an image of the time-dependent change of each of the amine-treated maxine aqueous solution after amine treatment by binding maxin and different amine ligands according to another embodiment of the present invention.
22 is a graph showing the change in the absorption wavelength spectrum of the amine-treated maxine aqueous solution according to another embodiment of the present invention.
Each of FIGS. 23 to 25 is a graph for XPS analysis of an amine-treated aqueous solution of maxine according to another embodiment of the present invention.
26 is a graph for XRD analysis of an amine-treated aqueous solution of maxine according to another embodiment of the present invention.
27 is an SEM image according to another embodiment of the present invention.
28 is a comparative image of a maxine aqueous solution according to another embodiment of the present invention and a solution in which maxin is dispersed according to another embodiment.
29 is a graph showing a relationship between the number of washing processes for maxine and electrical resistance of a film using maxine according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be “connected (connected, contacted, coupled)” with another part, it is not only “directly connected” but also “indirectly connected” with another member interposed therebetween. "Including cases where In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as "comprises" or "have" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

MXene means a transition metal carbide and a transition metal carbonitride having a two-dimensional structure, and is a two-dimensional layered structure, in which layers composed of atoms are stacked to form a multi-layered structure. The maxine, which is such a two-dimensional multilayer structure, is characterized in that it is light and has a low density, and can be easily separated from each other.

Maxine can be applied to a transparent conductive thin film used for an electrode of a battery, a supercapacitor, a support material for platinum nanoparticles in a fuel cell, an electrode, or a sensor. In addition, some properties of maxine are similar to graphene, a nanolayer structure that has a large specific surface area and good electrical conductivity and can be used for EMI shielding, so maxine can also be used for EMI shielding. Maxine may be represented by the following [Formula 1].

[Formula 1]

M _n+1 X _n T _x

Here, M is at least one transition metal selected from Groups 3 to 6 elements of the Periodic Table of the Elements, X is carbon (C), nitrogen (N) or a combination thereof, and Tx is oxide (O), epoxide side, hydroxide (OH), alkoxide having 1 to 5 carbon atoms, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof, and n is 1, 2 or three.

M may be at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W. And, Maxine is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ and may be composed of any one of _{Nb 4} C _{3 .}

Maxine can be obtained by removing the A atomic layer from the inorganic compound of the composition _{M n+1} AX _n. Here, M is at least one transition metal selected from Groups 3 to 6 elements of the Periodic Table of the Elements, A is at least one selected from Groups 12 to 16 elements of the Periodic Table of the Elements, and X is carbon (C ), nitrogen (N), or a combination thereof, and n may be 1, 2, or 3.

A may be at least one selected from Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl, and Pb. And, the inorganic compound of _{M n+1} AX _{n composition is Ti 2} CdC, Sc ₂ InC, Ti ₂ AlC, Ti ₂ GaC, Ti ₂ InC, Ti ₂ TIC, V ₂ AlC, V ₂ GaC, Cr ₂ GaC, Ti ₂ AlN, Ti ₂ GaN, Ti ₂ InN, V ₂ GaN, Cr ₂ GaN, Ti ₂ GeC, Ti ₂ SnC, Ti ₂ PbC, V ₂ GeC, Cr ₂ AlC, Cr ₂ GeC, V ₂ PC, V ₂ AsC , Ti ₂ SC, Zr ₂ InC, Zr ₂ TlC, Nb ₂ AlC, Nb ₂ GaC, Nb ₂ InC, Mo ₂ GaC, Zr ₂ InN, Zr ₂ TlN, Zr ₂ SnC, Zr ₂ PbC, Nb ₂ SnC, Nb ₂ PC, Nb ₂ AsC, Zr ₂ SC, Nb ₂ SC, Hf ₂ InC, Hf ₂ TlC, Ta ₂ AlC, Ta ₂ GaC, Hf ₂ SnC, Hf ₂ PbC, Hf ₂ SnN, Hf ₂ SC; Ti ₃ AlC ₂ , V ₃ AlC ₂ , Ti ₃ SiC ₂ , Ti ₃ GeC ₂ , Ti ₃ SnC ₂ , Ta ₃ AlC ₂ , Ti ₄ AlN ₃ , V ₄ AlC ₃ , Ti ₄ GaC ₃ , Ti ₄ SiC ₃ , It may be one or more selected from _{Ti 4} GeC ₃ , Nb ₄ AlC ₃ , and Ta ₄ AlC _{3 .}

The removal of the A atomic layer is performed by hydrofluoric acid (HF), hydrochloric acid (HCl), LiHF ₂ , NaHF ₂ , KHF ₂ , lithium fluoride (LiF), sodium fluoride (NaF), magnesium fluoride (MgF ₂ ), strontium fluoride (SrF _{2 ).} ), beryllium fluoride (BeF ₂ ), calcium fluoride (CaF ₂ ), ammonium fluoride (NH ₄ F), ammonium difluoride (NH ₄ HF ₂ ), ammonium hexafluoroaluminate ((NH ₄ ) ₃ AlF ₆ ) or It may be carried out using one or more selected from a combination thereof, or a combination thereof with one or more of hydrochloric acid, sulfuric acid and nitric acid. For example, maxine can be obtained by removing the atomic layer A from the inorganic compound of _{the M n+1} AX _n composition using hydrofluoric acid at room temperature or elevated temperature conditions.

Maxine obtained through the above process contains a short surface functional group, for example, an alkoxy group (-O), a hydroxyl group (-OH) and a fluoro group (-F) on the surface, and a relatively polar solvent, such as For example, it has the characteristic of being well dispersed in water.

First, an embodiment of the method for improving oxidation stability of the present invention will be described.

1 is an image of the change over time of an aqueous solution of maxine not treated with amine according to an embodiment of the present invention. And, each of FIGS. 2 to 17 is an image of the time-dependent change of each mixed solution after stirring each different amine solution in the maxine aqueous solution according to an embodiment of the present invention. In each of FIGS. 2 to 17 (a) the image may represent the molecular structure of the substance put into the maxine aqueous solution in each experimental example.

Here, the amine treatment may refer to a treatment process of binding an amine ligand to the surface of the maxine particle. Hereinafter, it is the same.

In the method for improving oxidation stability of the present invention, first, in the first step, an amine solution may be added to an aqueous solution of MXene. And, in the second step, by stirring the maxine aqueous solution and the amine solution to form a mixed solution, the amine ligand can be bound to the particle surface of the maxine.

The amine solution may be dropped into the container containing the maxine aqueous solution, and after the amine solution is added, the container may be moved to a stirrer, and a stirring bar of the stirrer may be put into the container and stirred. At this time, the stirring of the maxine aqueous solution and the amine solution may be performed at room temperature for 12 hours or more. Preferably, it can be carried out for 24 hours. And, it may be performed at a stirring speed of 200 rpm to 600 rpm.

The amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and may be any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline. In addition, the amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and may be a mixture of two or more substances selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline.

In the method for improving oxidation stability of the present invention, by inducing surface bonding by adding an amine ligand to the maxine aqueous solution, the amine ligand is bound to the surface of the maxine particle to prevent oxidation of the maxine. That is, the oxidative stability of maxine can be improved by the amine ligand.

In the amine used for this purpose, not all amine ligands implement the effect, and the effect may be realized when some amines as described above are used. And, among the above-described amines, Pyrrole can implement the most excellent effect. Details thereof will be described in the comparison of each experimental example.

In the second step, maxin may be stored for a predetermined time in a state in which it is bound with an amine ligand. Specifically, when using Pyrrole as an amine, the color of the mixed solution does not change for 10 days, so it can be experimentally confirmed that maxin present in the mixed solution is stored without being oxidized by amine treatment. That is, when maxin is stored according to the method for improving oxidation stability of the present invention, the storage period of maxin can be significantly increased. This will be further described in each related experimental example.

In the method for improving oxidation stability of the present invention, in the third step, the amine ligand is separated from the maxine, and the maxine can be redispersed in a polar solvent. Here, in the third step, a solution for dissolving the amine ligand is added to the mixed solution containing the amine-treated maxin, and centrifugation is performed to precipitate the maxine in step 3-1, in which the amine ligand separated from the maxine is dissolved. A step 3-2 of discharging the solution, and a step 3-3 of redispersing the precipitated maxine in a polar solvent may include.

In step 3-1, the solution may be isopropyl alcohol (Isopropyl alcohol). However, the present invention is not limited thereto, and any solution capable of dissolving the amine ligand such as ethanol may be used. Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. By such centrifugal separation, maxine may be deposited on the inner surface of the container. In addition, in the 3-2 step, by discarding the solution in which the amine ligand separated from the maxine is dissolved, there may be only the maxine separated from the amine ligand in the container. And, in the third step 3-3, water may be used as the polar solvent, and by redispersing the maxine in water, the maxine may be changed to a usable state for manufacturing a film or the like.

Steps 3-1 to 3-3 may be performed multiple times. And, by performing the steps 3-1 to 3-3 a plurality of times, the electrical resistance of the maxine film, which is a film formed using the maxim, may be reduced.

The process in which steps 3-1 to 3-3 are performed may be referred to as a washing process, and by performing such a washing process a plurality of times, the separation rate of amine ligands bound to maxine is improved, and maxine and The bound amine ligand can be completely removed. When an amine ligand is present on the maxine surface, a phenomenon such as an increase in electrical resistance of the film may occur when a film is formed using such maxine. In order to prevent such a phenomenon, a plurality of washing processes are required as described above, and when an amine ligand is removed from maxine through the washing process and then a film is formed, electrical resistance may be reduced.

After the third step, it is possible to form a maxine film on the filter paper by performing vacuum filtration using the aqueous maxine solution formed by redispersion.

Hereinafter, each of the experimental examples related to an embodiment of the method for improving oxidation stability of the present invention will be described.

[Experimental Example 1]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Four containers containing such an aqueous solution of Maxine were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and the color change was observed. , The third container was stored in an oven at 70 degrees (℃) for 2 days, and the color change was observed, and the fourth container was stored in an oven at 70 degrees (℃) for 2 days, and the color change was observed.

[Experimental Example 2]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M concentration of furan solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, four containers (transparent containers, hereinafter the same) containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was placed in an oven at 70 degrees (℃) for 1 The color change was observed while stored for one day, and the color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days, and the fourth container was stored in an oven at 70 degrees (℃) for 9 days. A color change was observed.

[Experimental Example 3]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M thiophene solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, four containers containing such a mixture were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and the color change was observed. The color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days, and the color change was observed while the fourth container was stored in an oven at 70 degrees (℃) for 9 days.

[Experimental Example 4]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M concentration of toluene solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, four containers containing such a mixture were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and the color change was observed. The color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days, and the color change was observed while the fourth container was stored in an oven at 70 degrees (℃) for 9 days.

[Experimental Example 5]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M concentration of pyridazine solution as an amine solution was added to the maxine aqueous solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixture were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and observed for color change. The color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days.

[Experimental Example 6]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of an imidazole solution of 1 M concentration as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixture were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and observed for color change. The color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days.

[Experimental Example 7]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M pyrimidine solution as an amine solution was added to the maxine aqueous solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixture were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and observed for color change. The color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days.

[Experimental Example 8]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M pyridine solution as an amine solution was added to the maxine aqueous solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, 5 containers containing such a mixture were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 1 day and observed for color change. The color change was observed while the third container was stored in an oven at 70 degrees (℃) for 2 days, and the color change was observed while the fourth container was stored in an oven at 70 degrees (℃) for 3 days. And, the fifth container was stored in an oven at 70 degrees (℃) for 9 days, and the color change was observed.

[Experimental Example 9]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M aniline solution as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 10]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M cyclohexylamine solution as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixture. .

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 11]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M pyrrole solution as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 12]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M pyrrolidine solution as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixture. .

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 13]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M butylamine solution as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 14]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M solution of amylamine as an amine solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 15]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M hexylamine solution as an amine solution was added to the maxine aqueous solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 16]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of a 1 M benzene solution was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

[Experimental Example 17]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, 15 ml of NMP (N-Methyl-2-pyrrolidone) solution of 1 M concentration was added to this aqueous maxine solution, and then, using a stirrer, the maxine aqueous solution and the amine solution were stirred for 24 hours at a stirring speed of 450 rpm to form a mixed solution did.

Then, three containers containing such a mixed solution were prepared, the first container was observed for color change at room temperature for 24 hours, and the second container was stored in an oven at 70 degrees (℃) for 3 days and the color change was observed. The third container was stored in an oven at 70 degrees (℃) for 10 days, and the color change was observed.

The analysis on the oxidation stability of Maxine is mainly performed by a 70 degree (℃) oxidation test, and it will be described below focusing on this. As shown in each image, when maxine is oxidized, it can be seen that the mixed solution in the container becomes transparent. Each container image is an image in the final observation state after the corresponding experiment.

Figure 1 is an image of each container of [Experimental Example 1], Figure 1 (a) is an image of the first container, Figure 1 (b) is an image of the second container, Figure 1 ( c) is an image of the third container, (d) of FIG. 1 is an image of the fourth container.

Figure 2 is an image of each container of [Experimental Example 2], Figure 2 (b) is an image of the first container, Figure 2 (c) is an image of the second container, Figure 2 ( d) is an image of the third container, and (e) of FIG. 2 is an image of the fourth container. In addition, Figure 3 is an image of each container of [Experimental Example 3], Figure 3 (b) is an image of the first container, Figure 3 (c) is an image of the second container, Figure 3 (d) is an image of the third container, (e) of Figure 3 is an image of the fourth container. And, Figure 4 is an image of each container of [Experimental Example 4], Figure 4 (b) is an image of the first container, Figure 4 (c) is an image of the second container, Figure 4 (d) is an image of the third container, (e) of Figure 4 is an image of the fourth container.

Figure 5 is an image of each container of [Experimental Example 5], Figure 5 (b) is an image of the first container, Figure 5 (c) is an image of the second container, Figure 5 ( d) is an image of the third container. In addition, Figure 6 is an image of each container of [Experimental Example 6], Figure 6 (b) is an image of the first container, Figure 6 (c) is an image of the second container, Figure 6 (d) is an image of the third container. In addition, Figure 7 is an image of each container of [Experimental Example 7], Figure 7 (b) is an image of the first container, Figure 7 (c) is an image of the second container, Figure 7 (d) is an image of the third container. And, Figure 8 is an image of each container of [Experimental Example 8], Figure 8 (b) is an image of the first container, Figure 8 (c) is an image of the second container, Figure 8 of (d) is an image of the third container, (e) of FIG. 8 is an image of the fourth container, and (f) of FIG. 8 is an image of the fifth container.

9 is an image of each container of [Experimental Example 9], FIG. 9 (b) is an image of the first container, FIG. 9 (c) is an image of the second container, and FIG. d) is an image of the third container. In addition, FIG. 10 is an image of each container of [Experimental Example 10], FIG. 10 (b) is an image of the first container, FIG. 10 (c) is an image of the second container, and FIG. (d) is an image of the third container. 11 is an image of each container of [Experimental Example 11], (b) of FIG. 11 is an image of the first container, (c) of FIG. 11 is an image of the second container, and FIG. (d) is an image of the third container. And, Figure 12 is an image of each container of [Experimental Example 12], Figure 12 (b) is an image of the first container, Figure 12 (c) is an image of the second container, Figure 12 (d) is an image of the third container.

13 is an image of each container of [Experimental Example 13], FIG. 13 (b) is an image of the first container, FIG. 13 (c) is an image of the second container, d) is an image of the third container. 14 is an image of each container of [Experimental Example 14], (b) of FIG. 14 is an image of the first container, (c) of FIG. 14 is an image of the second container, and FIG. (d) is an image of the third container. And, Figure 15 is an image of each container of [Experimental Example 15], Figure 15 (b) is an image of the first container, Figure 15 (c) is an image of the second container, Figure 15 (d) is an image of the third container.

16 is an image of each container of [Experimental Example 16], FIG. 16 (b) is an image of the first container, FIG. 16 (c) is an image of the second container, and FIG. d) is an image of the third container. And, Figure 17 is an image of each container of [Experimental Example 17], Figure 17 (b) is an image of the first container, Figure 17 (c) is an image of the second container, Figure 17 (d) is an image of the third container.

In FIG. 1, as shown in the image of each container of [Experimental Example 1], it can be seen that the aqueous solution of maxine without any treatment is completely oxidized in 3 days in the 70 degree (℃) oxidation test and the mixed solution becomes transparent. . Accordingly, it can be confirmed that the oxidation stability of maxine is relatively reduced.

2 to 4, in [Experimental Example 2] to [Experimental Example 4], an organic solvent other than an amine-based solvent was added to the maxine aqueous solution, and although there is a difference in the degree of transparency of the mixed solution, 70 degrees (℃ ) In the oxidation test, it can be confirmed that all of the mixture is oxidized in 9 days and the mixture becomes transparent. And, as shown in FIGS. 16 and 17, in [Experimental Example 16] and [Experimental Example 17], other organic solvents other than the amine series were added to the maxine aqueous solution, and although there is a difference in the degree of transparency of the mixed solution, 70 degrees In the (℃) oxidation test, it can be confirmed that all of the mixture is oxidized in 9 days and the mixture becomes transparent. Accordingly, it can be confirmed that the oxidation stability of maxine is increased when an organic solvent, not an amine-based solvent, is added to the maxine aqueous solution than in the case of [Experimental Example 1] without any treatment.

As shown in FIGS. 5 to 15 , in [Experimental Example 5] to [Experimental Example 15], the amine solution was added to the maxine solution, and in each experimental example, the time at which the mixed solution became transparent was different depending on the type of the amine solution. can be checked. And, as shown in FIGS. 5 to 15 , when amine treatment is performed by adding a pyridine solution of [Experimental Example 8] or a pyrrole solution of [Experimental Example 11] to an aqueous solution of maxine, oxidation of maxine It can be seen that the stability is significantly increased. Specifically, as shown in FIG. 8, when a pyridine solution is used as the amine solution, the color of the mixed solution remains opaque until 3 days in the 70 degree (℃) oxidation test, and as shown in FIG. 11, the amine solution In the case of using a pyrrole solution, it can be confirmed that the color of the mixed solution remains opaque for up to 10 days in the 70 degree (℃) oxidation test. When the pyrrole solution is added to the aqueous solution of maxine, it can be seen that the oxidative stability of maxine is the best.

As described above, when a specific amine solution such as a pyrrole solution is added to the maxine aqueous solution, the oxidative stability of the maxine is significantly increased, and it can be confirmed that the maxine can be stored for a long time in a stable state. In addition, it can be confirmed that there is a storage effect of maxin in the case of imidazole, pyrimidine, pyridazine or aniline in addition to pyrrole and pyridine.

Hereinafter, another embodiment of the method for improving oxidation stability of the present invention will be described.

Each of FIGS. 18 to 21 is an image of the time-dependent change of each of the amine-treated maxine aqueous solution after amine treatment by binding maxin and different amine ligands according to another embodiment of the present invention.

In the method for improving oxidation stability of the present invention, first, in the first step, maxine may be precipitated by centrifuging an aqueous solution of maxine (MXene). Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. By such centrifugal separation, maxine may be deposited on the inner surface of the container. And, the solution removed by the precipitation of maxin can be discharged.

In the second step, by stirring the precipitated maxine and amine solution, the maxine is dispersed in the amine solution, and the amine ligand can be bound to the particle surface of the maxine. Specifically, the amine solution may be put into the container of the first step, the container may be moved with a stirrer, and a stirrer bar of the stirrer may be put into the container and stirred. At this time, the agitation of the maxine and the amine solution may be performed at room temperature for 12 hours or more. Preferably, it can be carried out for 24 hours. And, it may be performed at a stirring speed of 200 rpm to 600 rpm. By performing the stirring as described above, maxin can be well dispersed in the amine solution.

The amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and may be any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline. In addition, the amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and may be a mixture of two or more substances selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline.

In the method for improving oxidation stability of the present invention, by inducing surface binding by adding an amine ligand to the maxine, the amine ligand is bound to the surface of the maxine particle to prevent oxidation of the maxine. That is, the oxidative stability of maxine can be improved by the amine ligand.

In the amine used for this purpose, not all amine ligands implement the effect, and the effect may be realized when some amines as described above are used. And, among the above-described amines, Pyrrole can implement the most excellent effect. Details thereof will be described in the comparison of each experimental example.

In the method for improving oxidation stability of the present invention, in the third step, the amine-treated maxine may be precipitated by centrifuging the amine solution in which the maxine is dispersed. Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. The amine-treated maxine by such centrifugation may be deposited on the inner surface of the container. In addition, the amine-treated maxine precipitated and removed solution may be discharged. That is, even if maxin is re-precipitated by centrifugation, the re-precipitated maxin may be in a surface-bonded state with an amine ligand.

In the method for improving oxidation stability of the present invention, in the fourth step, the amine-treated maxine is dispersed in water to form an amine-treated maxine aqueous solution. Here, after the amine-treated maxine is added to water, the container may be moved to a stirrer, and a stirrer bar of the stirrer may be placed in the container and stirred. At this time, the stirring of the amine-treated maxine and water may be performed at room temperature for 12 hours or more. Preferably, it can be carried out for 24 hours. And, it may be performed at a stirring speed of 200 rpm to 600 rpm.

In the fourth step, maxin may be stored for a predetermined time in a state in which it is bound with an amine ligand. Specifically, when using Pyrrole as an amine, the color of the mixed solution does not change for 10 days, so it can be experimentally confirmed that maxin present in the mixed solution is stored without being oxidized by amine treatment. That is, when maxin is stored according to the method for improving oxidation stability of the present invention, the storage period of maxin can be significantly increased. This will be further described in each related experimental example.

In the method for improving oxidation stability of the present invention, in the fifth step, the amine ligand is separated from the maxine, and the maxine can be redispersed in a polar solvent. Here, in the fifth step, a solution dissolving the amine ligand is added to the amine-treated maxine aqueous solution and centrifugation is performed to precipitate the maxine step 5-1, discharging the solution in which the amine ligand is dissolved from the maxine It may include a step 5-2, and a step 5-3 of redispersing the precipitated maxine in a polar solvent.

In step 5-1, the solution may be isopropyl alcohol (Isopropyl alcohol). However, the present invention is not limited thereto, and any solution capable of dissolving the amine ligand such as ethanol may be used. Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. By such centrifugal separation, maxine may be deposited on the inner surface of the container. In addition, in step 5-2, the solution in which the amine ligand separated from the maxine is dissolved is discarded, so that only the maxine separated from the amine ligand can be in the container. And, in the step 5-3, water may be used as the polar solvent, and by redispersing the maxine in water, the maxine may be changed to a usable state for the production of a film or the like.

Steps 5-1 to 5-3 may be performed multiple times. And, by performing the steps 5-1 to 5-3 a plurality of times, the electrical resistance of the maxine film, which is a film formed using maxim, may be reduced.

The process in which steps 5-1 to 5-3 are performed may be referred to as a washing process, and by performing such a washing process a plurality of times, the separation rate of amine ligands bound to maxine is improved, and maxine and The bound amine ligand can be completely removed. When an amine ligand is present on the maxine surface, a phenomenon such as an increase in electrical resistance of the film may occur when a film is formed using such maxine. In order to prevent such a phenomenon, a plurality of washing processes are required as described above, and when an amine ligand is removed from maxine through the washing process and then a film is formed, electrical resistance may be reduced.

After the fifth step, it is possible to form a maxine film on the filter paper by performing vacuum filtration using the aqueous maxine solution formed by redispersion.

Hereinafter, each of the experimental examples related to another embodiment of the method for improving oxidation stability of the present invention will be described.

[Experimental Example 18]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. This aqueous solution of maxin was placed in a transparent container and stored at room temperature, and the colors were observed for each hour of 1 day, 2 days, 9 days, 14 days, 22 days, 30 days, 37 days, and 45 days.

[Experimental Example 19]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, a transparent container containing the Maxim aqueous solution was placed in a centrifuge and centrifugation was performed at a centrifugation speed of 5,000 rpm so that 30 mg of maxin was detected on the wall of the container. Next, a pyridine (Pyridine) solution is put into the container, the container is moved with a stirrer, and the maxine and pyridine solution are stirred at room temperature for 24 hours at a stirring speed of 450 rpm, and the maxine precipitated in the pyridine solution was allowed to disperse. After that, the vessel was placed in a centrifuge again and centrifugation was performed at a centrifugation speed of 5,000 rpm so that amine-treated maxin was detected on the wall of the vessel, and the clear solution produced by centrifugation was discharged. Then, 15ml of water was put into the container, and then the container was moved with a stirrer, and the amine-treated maxin and water were stirred at a stirring speed of 450 rpm at room temperature for 1 hour to disperse the amine-treated maxin in the water. Then, while the container was stored at room temperature, the colors were observed for each hour of 1 day, 2 days, 9 days, 14 days, 22 days, 30 days, 37 days, and 45 days.

[Experimental Example 20]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, a transparent container containing the Maxim aqueous solution was placed in a centrifuge and centrifugation was performed at a centrifugation speed of 5,000 rpm so that 30 mg of maxin was detected on the wall of the container. Next, a pyrrole solution is put into the container, the container is moved with a stirrer, and the maxine and pyrrole solution precipitated at room temperature for 24 hours at a stirring speed of 450 rpm are stirred, and the maxine precipitated in the pyrrole solution was allowed to disperse. After that, the vessel was placed in a centrifuge again and centrifugation was performed at a centrifugation speed of 5,000 rpm so that amine-treated maxin was detected on the wall of the vessel, and the clear solution produced by centrifugation was discharged. Then, 15ml of water was put into the container, and then the container was moved with a stirrer, and the amine-treated maxin and water were stirred at a stirring speed of 450 rpm at room temperature for 1 hour to disperse the amine-treated maxin in the water. Then, while the container was stored at room temperature, the colors were observed for each hour of 1 day, 2 days, 9 days, 14 days, 22 days, 30 days, 37 days, and 45 days.

[Experimental Example 21]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, a transparent container containing the Maxim aqueous solution was placed in a centrifuge and centrifugation was performed at a centrifugation speed of 5,000 rpm so that 30 mg of maxin was detected on the wall of the container. Next, put a pyrrolidine solution in the container, move the container to a stirrer, and stir the precipitated maxine and pyrrolidine solution at a stirring speed of 450 rpm at room temperature for 24 hours to stir the pyrrolidine (pyrrolidine) solution. ) was allowed to disperse the maxine precipitated in the solution. After that, the vessel was placed in a centrifuge again and centrifugation was performed at a centrifugation speed of 5,000 rpm so that amine-treated maxin was detected on the wall of the vessel, and the clear solution produced by centrifugation was discharged. Then, 15ml of water was put into the container, and then the container was moved with a stirrer, and the amine-treated maxin and water were stirred at a stirring speed of 450 rpm at room temperature for 1 hour to disperse the amine-treated maxin in the water. Then, while the container was stored at room temperature, the colors were observed for each hour of 1 day, 2 days, 9 days, 14 days, 22 days, 30 days, 37 days, and 45 days.

18 to 21, container a is a container of [Experimental Example 18], container b is a container of [Experimental Example 19], container c is a container of [Experimental Example 20], and container d is [Experimental Example 21] ] is the courage of

Fig. 18 (a) is an image comparing and observing each container after 1 day (24 hours), and Fig. 18 (b) is an image comparing and observing each vessel after 2 days. In addition, (a) of FIG. 19 is an image of comparative observation of each container after 9 days, and (b) of FIG. 19 is an image of comparison and observation of each container after 14 days. In addition, (a) of FIG. 20 is an image comparing and observing each container after 22 days, and FIG. 20 (b) is an image of comparing and observing each container after 30 days. And, (a) of FIG. 21 is an image of comparative observation of each container after 37 days, and (b) of FIG. 21 is an image of comparative observation of each container after 45 days.

As shown in each of the container images of FIGS. 18 to 21 , it was confirmed that, in the case of the aqueous maxine solution that was not treated with the amine, significant clearing progressed after 14 days, and it was confirmed that the transparent state was maintained after 14 days.

18 to 21 , in the case of the amine-treated maxine aqueous solution with pyridine, no color change was observed with the naked eye even after 45 days had elapsed, as shown in the images of the container b of FIGS. 18 to 21 . And, as shown in the images of each container c of FIGS. 18 to 21 , even in the case of the aqueous solution of maxine treated with pyrrole amine, no change in color was observed with the naked eye after 45 days had elapsed.

As shown in the d container image of each of FIGS. 18 to 21, in the case of an aqueous solution of maxine treated with pyrrolidine with pyrrolidine, a change in color was observed at the time point 22 days elapsed, and 30 days had elapsed. It was observed to become translucent at time points.

22 is a graph showing the change in the absorption wavelength spectrum of the amine-treated maxine aqueous solution according to another embodiment of the present invention. Here, when the Normalized Intensity is 1, it may mean that all of the irradiated light is absorbed, and when the Normalized Intensity is 0, it may mean that all of the irradiated light is transmitted. That is, the decrease in Normalized Intensity may mean that the maxine (Ti ₃ C ₂ ) is _{changed to TiO 2} and disappears.

Here, [Experimental Example 18] to [Experimental Example 21] each vessel was irradiated with light (UV-VIS) to measure the intensity change at the absorption peak 750nm.

[Experimental Example 18] to [Experimental Example 21] When light was irradiated to the container of each experimental example, in the container of [Experimental Example 18] that was not treated at all, it decreased to 70% or less of the initial value in 3 days, and 14 days passed At one point in time, the color of the aqueous solution of Maxine becomes transparent, and the absorption wavelength spectrum approaches 0, and in the container of [Experimental Example 21] treated with pyrrolidine, the color of the aqueous solution of Maxine becomes transparent at the time of 22 days at the absorption wavelength of the seabed It can be seen that the spectrum is close to zero.

And, in the container of [Experimental Example 19] treated with pyridine, although the Normalized Intensity value decreased until 18 days elapsed, it was confirmed that the value was maintained above 0.5 after that point. In addition, even in the container of [Experiment 20] treated with pyrrole, although the Normalized Intensity value decreased until 18 days elapsed, it was confirmed that the value was maintained above 0.5 after that time, and the highest Normalized Intensity value was maintained. Thus, it can be confirmed that more than 70% of the initial value is maintained.

In the case of the room temperature test as described above, it can be confirmed that the oxidative stability of maxine is excellent in an aqueous solution of maxine treated with pyrrole or pyridine. In particular, as shown in the graph of FIG. 22, it can be confirmed that the amine-treated maxine using pyrrole has the best oxidation stability. As such, when the amine-treated maxine is dispersed in water using a specific amine to form an amine-treated maxine aqueous solution, the oxidative stability of the maxine is remarkably increased, and it can be confirmed that the maxine can be stored for a long time in a stable state. And, it can be confirmed that even in the case of pyrrolidine (pyrrolidine) there is a storage effect of the maxine.

Each of FIGS. 23 to 25 is a graph for XPS analysis of an amine-treated aqueous solution of maxine according to another embodiment of the present invention. Here, FIGS. 23 to 25 are graphs for confirming that the amine ligand is bound to the surface of maxine by performing XPS analysis on each of [Experimental Example 19] to [Experimental Example 21] amine-treated aqueous maxine solution. . 23 (a) and (b) are graphs and data tables for the case of performing XPS analysis on an aqueous solution of maxine amine-treated with pyridine of [Experimental Example 19], and FIG. 24 (a) and (b) is a graph and data table for the case of performing XPS analysis on the aqueous solution of maxine amine-treated with pyrrole of [Experimental Example 20], (a) and (b) of FIG. 25 are [Experimental Example] 21] is a graph and data table for the case of performing XPS analysis on the amine-treated Maxine aqueous solution with pyrrolidine.

As shown in FIGS. 23 to 25 , maxine (Ti ₃ C ₂ ) included in the amine-treated aqueous maxine solution performs surface bonding with an amine ligand, thereby confirming that an N bond is formed. Accordingly, it can be confirmed through XPS analysis that the oxidative stability of maxin is increased by binding between maxin and an amine ligand.

26 is a graph for XRD analysis of an amine-treated aqueous solution of maxine according to another embodiment of the present invention. In FIG. 26, [Experimental Example 18] to [Experimental Example 21] XRD analysis was performed on each amine-treated aqueous solution of maxine to bind the amine ligand to the surface of maxine, thereby increasing the spacing between maxine particles (MXene flakes). It can be confirmed by XRD peak.

In FIG. 26, graph a is a graph for the case of performing XRD analysis on the aqueous solution of maxine of [Experimental Example 18], and graph b is the XRD of the aqueous solution of maxine treated with amine with pyridine of [Experimental Example 19] It is a graph for the case of performing the analysis, graph c is a graph for the case of performing XRD analysis on the aqueous solution of maxine treated with pyrrole amine of [Experimental Example 20], and graph d is [Experimental Example 21] It is a graph for the case of performing XRD analysis on the amine-treated Maxine aqueous solution with pyrrolidine.

As shown in Figure 26, it can be confirmed that the N peak is formed in the XRD graph for the amine-treated maxine aqueous solution, and the maxine (Ti ₃ C ₂ ) contained in the amine-treated maxine aqueous solution is surface-bonded with the amine ligand. It can be confirmed that an N bond is formed.

Hereinafter, another embodiment of the method for improving oxidation stability of the present invention will be described. In the method for improving oxidation stability of the present invention, first, in the first step, maxine may be precipitated by centrifuging an aqueous solution of maxine (MXene). Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. By such centrifugal separation, maxine may be deposited on the inner surface of the container. And, the solution removed by the precipitation of maxin can be discharged.

In the second step, by stirring the precipitated maxine and amine solution, the maxine is dispersed in the amine solution, and the amine ligand can be bound to the particle surface of the maxine. Specifically, the amine solution may be put into the container of the first step, the container may be moved with a stirrer, and a stirrer bar of the stirrer may be put into the container and stirred. At this time, the agitation of the maxine and the amine solution may be performed at room temperature for 12 hours or more. Preferably, it can be carried out for 24 hours. And, it may be performed at a stirring speed of 200 rpm to 600 rpm. By performing the stirring as described above, maxin can be well dispersed in the amine solution.

The amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and may be any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline. In addition, the amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and may be a mixture of two or more substances selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline.

In the method for improving oxidation stability of the present invention, by inducing surface binding by adding an amine ligand to the maxine, the amine ligand is bound to the surface of the maxine particle to prevent oxidation of the maxine. That is, the oxidative stability of maxine can be improved by the amine ligand.

In the amine used for this purpose, not all amine ligands implement the effect, and the effect may be realized when some amines as described above are used. And, among the above-mentioned amines, Pyridine and Pyrrole can realize the most excellent effect. Details thereof will be described in the following experimental examples.

In the method for improving oxidation stability of the present invention, in the third step, the amine-treated maxine may be precipitated by centrifuging the amine solution in which the maxine is dispersed. Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. The amine-treated maxine by such centrifugation may be deposited on the inner surface of the container. In addition, the amine-treated maxine precipitated and removed solution may be discharged. That is, even if maxin is re-precipitated by centrifugation, the re-precipitated maxin may be in a surface-bonded state with an amine ligand.

In the method for improving oxidation stability of the present invention, in the fourth step, the amine-treated maxine is dispersed in an organic solvent to form an organic solution in which the amine-treated maxine is dispersed. Here, after the amine-treated maxine is added to the organic solvent, the container may be moved to a stirrer, and a stirrer bar of the stirrer may be placed in the container and stirred. At this time, the stirring of the amine-treated maxine and water may be performed at room temperature for 12 hours or more. Preferably, it can be carried out for 24 hours. And, it may be performed at a stirring speed of 200 rpm to 600 rpm.

When the amine-treated maxine is added to the organic solvent as described above, in the fourth step, the organic solvent may be an amine solution, specifically, may be an amine solution of the same type as the amine ligand bound to the surface of the maxine. However, the present invention is not limited thereto, and other types of amine solutions may be used, but when the same type of amine solutions are used, the storage performance of the maxine may be further improved.

In the fourth step, maxin may be stored for a predetermined time in a state in which it is bound with an amine ligand. As such, when the amine-treated maxin is dispersed and stored in the amine solution, it may be possible to store the maxine for a long period of time in excess of the storage period of another embodiment of the method for improving oxidation stability of the present invention. That is, when maxin is stored according to the method for improving oxidation stability of the present invention, the storage period of maxin can be significantly increased. This will be described in detail in [Experimental Example 22] below.

In the method for improving oxidation stability of the present invention, in the fifth step, the amine ligand is separated from the maxine, and the maxine can be redispersed in a polar solvent. Here, in step 5, a solution dissolving amine in an organic solvent in which amine-treated maxin is dispersed is added, and centrifugation is performed to precipitate maxin, step 5-1, in which the amine ligand separated from maxine is dissolved A step 5-2 of discharging the solution, and a step 5-3 of redispersing the precipitated maxine in a polar solvent, may include.

In step 5-1, the solution may be isopropyl alcohol (Isopropyl alcohol). However, the present invention is not limited thereto, and any solution capable of dissolving the amine such as ethanol may be used. Here, high-speed centrifugation may be performed, and the centrifugation speed may be 3,000 rpm or more. By such centrifugal separation, maxine may be deposited on the inner surface of the container. In addition, in the step 5-2, by discarding the solution in which the amine separated from the maxine is dissolved, there may be only the maxine separated from the amine ligand in the container. And, in the step 5-3, water may be used as the polar solvent, and by redispersing the maxine in water, the maxine may be changed to a usable state for the production of a film or the like.

Steps 5-1 to 5-3 may be performed multiple times. And, by performing the steps 5-1 to 5-3 a plurality of times, the electrical resistance of the maxine film, which is a film formed using maxim, may be reduced.

The process in which steps 5-1 to 5-3 are performed may be referred to as a washing process, and by performing such a washing process a plurality of times, the separation rate of amine ligands bound to maxine is improved, and maxine and The bound amine ligand can be completely removed. When an amine ligand is present on the maxine surface, a phenomenon such as an increase in electrical resistance of the film may occur when a film is formed using such maxine. In order to prevent such a phenomenon, a plurality of washing processes are required as described above, and when an amine ligand is removed from maxine through the washing process and then a film is formed, electrical resistance may be reduced.

After the fifth step, it is possible to form a maxine film on the filter paper by performing vacuum filtration using the aqueous maxine solution formed by redispersion.

27 is an SEM image according to another embodiment of the present invention. Fig. 27 (a) is an SEM image of maxine particles that are not _{amine-treated and are not changed to TiO 2} It is an SEM image of Maxine particles after being stored in a low-temperature refrigerator at 5° C. for 30 days, and FIG. . And, FIG. 28 is a comparative image of a maxine aqueous solution according to another embodiment of the present invention and a solution in which maxine is dispersed according to another embodiment. Specifically, an aqueous solution of maxine amine-treated with pyridine according to the above [Experimental Example 19] (b) and maxine amine-treated with pyridine according to the following [Experimental Example 22] are dispersed in pyridine (Pyridine) ) A comparison image after storing the solution (a) for 6 months.

[Experimental Example 22]

30mg of maxin (Ti ₃ C ₂ ) 300ml of maxine aqueous solution (0.1mg/ml) containing was prepared. Then, a transparent container containing the Maxim aqueous solution was placed in a centrifuge and centrifugation was performed at a centrifugation speed of 5,000 rpm so that 30 mg of maxin was detected on the wall of the container. Next, a pyridine (Pyridine) solution is put into the container, the container is moved with a stirrer, and the maxine and pyridine solution precipitated in the pyridine solution are stirred at room temperature for 24 hours at a stirring speed of 450 rpm. was allowed to disperse. After that, the vessel was placed in a centrifuge again and centrifugation was performed at a centrifugation speed of 5,000 rpm so that amine-treated maxin was detected on the wall of the vessel, and the clear solution produced by centrifugation was discharged. Then, 15 ml of a pyridine solution was put into the container, and then the container was moved to a stirrer and the amine-treated maxine and pyridine solution were stirred at a stirring speed of 450 rpm at room temperature for 1 hour to add to the pyridine solution. The amine treated maxine was allowed to disperse. And, while the container was stored at room temperature, color by time was observed for 6 months.

As shown in the comparison of (a) and (b) of FIG. 27, compared with the SEM image of the unchanged Maxine, the amine-treated Maxine aqueous solution according to [Experimental Example 19] was placed in a low-temperature refrigerator at 5° C. for 30 days. After storage, it can be seen that some maxines change as shown in the image (b) of FIG. 27 . And, as shown in the comparison of (a) and (c) of FIG. 27, in comparison with the SEM image of the unaltered Maxine, Maxine in the organic solution in which the amine-treated Maxine is dispersed by [Experimental Example 22] is 6 Even after months have elapsed, it shows a shape similar to the image (a) of FIG. 27 .

And, as shown in FIG. 28, the aqueous maxine solution (b) amine-treated with pyridine according to [Experimental Example 19] was changed to be transparent at the time of 6 months, whereas by [Experimental Example 22], pyridine (Pyridine) amine-treated maxin-dispersed pyridine (Pyridine) solution (a) shows little change in color, indicating that maxine is stably stored for 6 months.

It can be experimentally confirmed that the same effect is realized even when other amines such as pyrrole are used in addition to pyridine. When the amine-treated maxine is stored in the amine solution as described above, the effect of water can be minimized, and thus the maxine can be stored stably for significantly longer than when stored in an aqueous solution.

29 is a graph showing a relationship between the number of washing processes for maxine and electrical resistance of a film using maxine according to an embodiment of the present invention. Specifically, FIG. 29 is a graph for the following [Experimental Example 23].

[Experimental Example 23]

A maxine film may be formed using maxine stored for 1 day (24 hours) in an aqueous solution of maxine treated with pyrrole with pyrrole of [Experimental Example 11]. Specifically, as described above, maxin is precipitated according to step 5 of an embodiment of the method for improving oxidative stability of the present invention and then redispersed in water, and maxin aqueous solution 100 μl (microliter) formed by redispersing maxin in this way is used. By performing vacuum filtration to form a maxine film on the filter paper. At this time, the first maxine film using the maxine subjected to the above-described washing steps 0 times, the second maxine film subjected to the washing process once, the third maxine film subjected to the washing process twice, and washing The process was performed three times to form a fourth maxine film. Here, in the N-th repetition of the washing process, an amount of water obtained by subtracting 100 μl from the amount of previously added water may be used as water for redispersion. Then, the sheet resistance for each maxine film was measured.

As shown in FIG. 29, it was confirmed that as the number of washing processes increased, the electrical resistance value of the maxine film decreased. Specifically, in the case of the first maxine film on which the washing process is not performed, the electrical resistance value is somewhat high as 2.2k ohm/sq, but in the case of the fourth maxine film on which the washing process is performed three times, the electrical resistance value is 46 ohm/sq. It can be seen that the sq decreases (the electrical resistance value is reduced by about 50 times). However, as the washing process is repeated, it can be seen that the decrease in the electrical resistance value becomes smaller.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (22)

A first step of adding an amine solution to an aqueous solution of MXene; and
A second step of binding the amine ligand to the particle surface of the maxine by stirring the aqueous solution of the maxine and the amine solution to form a mixed solution;
A method for improving the oxidative stability of maxine through surface functional group control, characterized in that the oxidative stability of maxine is improved by the amine ligand and the storage period of maxine is significantly increased.
The method according to claim 1,
A third step of separating the amine ligand from the maxine and redispersing the maxine in a polar solvent; further comprising,
The third step is
Step 3-1, in which a solution for dissolving an amine ligand is added to the mixed solution containing the amine-treated maxin, and centrifugation is performed to precipitate maxin;
Step 3-2 of discharging a solution in which the amine ligand separated from Maxine is dissolved, and
A method for improving oxidation stability of maxine through surface functional group control, comprising the step 3-3 of redispersing the precipitated maxin in a polar solvent.
3. The method according to claim 2,
The method of improving the oxidation stability of maxine through the control of the surface functional group, characterized in that the solution is isopropyl alcohol (Isopropyl alcohol).
3. The method according to claim 2,
The method for improving the oxidation stability of maxine through surface functional group control, characterized in that the step 3-1 to step 3-3 is performed a plurality of times.
5. The method according to claim 4,
By performing the steps 3-1 to 3-3 a plurality of times, the method for improving the oxidation stability of maxine through surface functional group control, characterized in that the electrical resistance of the maxine film, which is a film formed using maxim, is reduced. .
The method according to claim 1,
The amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and is any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline. A method of improving the oxidative stability of maxine through
The method according to claim 1,
In the second step, maxin is a method for improving oxidation stability of maxin through surface functional group control, characterized in that it is stored for a predetermined time in a state in which it is bound to an amine ligand.
A first step of precipitating maxine by centrifuging an aqueous solution of maxine (MXene);
a second step of stirring the precipitated maxine and an amine solution to disperse the maxine in the amine solution, and binding an amine ligand to the particle surface of the maxine;
A third step of precipitating the amine-treated maxine by centrifuging the amine solution in which the maxine is dispersed; and
A fourth step of dispersing the amine-treated maxine in water to form an amine-treated maxine aqueous solution;
A method for improving the oxidative stability of maxine through surface functional group control, characterized in that the oxidative stability of maxine is improved by the amine ligand and the storage period of maxine is significantly increased.
9. The method of claim 8,
A fifth step of separating the amine ligand from the maxine and redispersing the maxine in a polar solvent; further comprising,
The fifth step is
Step 5-1, in which a solution for dissolving an amine ligand is added to the amine-treated aqueous maxine solution and centrifuged to precipitate maxine;
Step 5-2 of discharging a solution in which the amine ligand separated from Maxine is dissolved, and
A method for improving oxidation stability of maxine through surface functional group control, comprising the step 5-3 of redispersing the precipitated maxin in a polar solvent.
10. The method of claim 9,
The method of improving the oxidation stability of maxine through the control of the surface functional group, characterized in that the solution is isopropyl alcohol (Isopropyl alcohol).
10. The method of claim 9,
The method for improving oxidation stability of maxine through surface functional group control, characterized in that the steps 5-1 to 5-3 are performed a plurality of times.
12. The method of claim 11,
By performing the steps 5-1 to 5-3 a plurality of times, the method for improving the oxidation stability of maxine through surface functional group control, characterized in that the electrical resistance of the maxine film, which is a film formed using maxim, is reduced. .
9. The method of claim 8,
The amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and is any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline. A method of improving the oxidative stability of maxine through
9. The method of claim 8,
In the fourth step, maxin is a method for improving oxidation stability of maxin through surface functional group control, characterized in that it is stored for a predetermined time in a state in which it is bound to an amine ligand.
A first step of precipitating maxine by centrifuging an aqueous solution of maxine (MXene);
a second step of stirring the precipitated maxine and an amine solution to disperse the maxine in the amine solution, and binding an amine ligand to the particle surface of the maxine;
A third step of precipitating the amine-treated maxine by centrifuging the amine solution in which the maxine is dispersed; and
A fourth step of dispersing the amine-treated maxine in an organic solvent to form an organic solution in which the amine-treated maxine is dispersed;
A method for improving the oxidative stability of maxine through surface functional group control, characterized in that the oxidative stability of maxine is improved by the amine ligand and the storage period of maxine is significantly increased.
16. The method of claim 15,
In the fourth step, the organic solvent is a method of improving the oxidation stability of maxine through surface functional group control, characterized in that the amine solution.
16. The method of claim 15,
A fifth step of separating the amine ligand from the maxine and redispersing the maxine in an organic solvent;
The fifth step is
Step 5-1 of adding a solution for dissolving an amine in an organic solvent in which the amine-treated maxin is dispersed and performing centrifugation to precipitate maxin;
Step 5-2 of discharging a solution in which the amine ligand separated from Maxine is dissolved, and
A method for improving oxidation stability of maxine through surface functional group control, comprising the step 5-3 of redispersing the precipitated maxin in a polar solvent.
18. The method of claim 17,
The method of improving the oxidation stability of maxine through the control of the surface functional group, characterized in that the solution is isopropyl alcohol (Isopropyl alcohol).
18. The method of claim 17,
The method for improving oxidation stability of maxine through surface functional group control, characterized in that the steps 5-1 to 5-3 are performed a plurality of times.
20. The method of claim 19,
By performing the steps 5-1 to 5-3 a plurality of times, the method for improving the oxidation stability of maxine through surface functional group control, characterized in that the electrical resistance of the maxine film, which is a film formed using maxim, is reduced. .
16. The method of claim 15,
The amine contained in the amine solution has a ring structure having one or more unsaturated bonds, and is any one material selected from the group consisting of Pyrrole, Pyridine, Imidazole, Pyrimidine, Pyridazine and aniline. A method of improving the oxidative stability of maxine through
16. The method of claim 15,
In the fourth step, maxin is a method for improving oxidation stability of maxin through surface functional group control, characterized in that it is stored for a predetermined time in a state in which it is bound to an amine ligand.

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