KR20190046252A - Conjugated molecule for selective separation of carbon nanotubes - Google Patents

Abstract

One embodiment of the present invention provides a conjugated polymer for a selective separation of single-walled carbon nanotubes (SWNT) containing semiconductive SWNT and metallic SWNT. The conjugated polymer is represented by chemical formula 1 in which M1 and M2 are monomers wherein M1 is an electron donor and M2 is an electron acceptor. Herein, R1 and R2 are alkyl substituents selected to be identical or different, and n is 1-10,000.

Description

{Conjugated Molecule for Selective Separation of Single Walled Carbon Nanotubes {

The present invention relates to a conjugated polymer, and more particularly, to a conjugated polymer for selective separation of single-walled carbon nanotubes.

Carbon nanotubes have been recognized as promising reinforcements for polymer composites because of their large surface area, high ratio of length to diameter, and excellent strength and elasticity. The strength and modulus of elasticity are far superior to those of high-strength / high-resilience carbon fiber and are considered to be among the best materials available.

In addition, since the electrical conductivity and the thermal conductivity are very high, it is possible to simultaneously impart structural strengthening electricity and heat conduction to the polymer composite material. As a result, carbon nanotubes are attracting attention in various fields such as aeronautics, space, automobiles, and electric and electronic devices.

Carbon nanotubes have a cylindrical structure in which hexagonal carbon bonds are interconnected to form a two-dimensional flat sheet of graphene. Carbon nanotubes may also be in the form of multi-walled carbon nanotubes, where single walled carbon nanotubes (SWNTs) of different diameters overlap each other according to the manufacturing method.

Single-walled carbon nanotubes have different chirality and diameters depending on which chiral vector they have and thus exhibit various electrical characteristics. SWNTs are again divided into semiconducting SWNTs (s-SWNTs) and metallic SWNTs (m-SWNTs).

Synthesized SWNTs have a lower industrial value than pure semiconducting SWNTs because semiconducting SWNTs (s-SWNTs) and metallic SWNTs (m-SWNTs) are mixed. Therefore, it is required to develop a technique for selectively separating semiconducting SWNTs from a SWNT mixture in which a semiconducting SWNT (s-SWNT) and a metallic SWNT (m-SWNT) are mixed.

Korean Patent No. 10-1744052

SUMMARY OF THE INVENTION The present invention provides a conjugated polymer for selectively separating semiconducting SWNTs (s-SWNTs) from single-walled carbon nanotube complexes (SWNTs) and a method for separating the same.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

According to an aspect of the present invention, there is provided a conjugated polymer for selectively separating single-walled carbon nanotubes.

The conjugated polymer for selective separation of the single walled carbon nanotube may be represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, M 1 is a monomer having an electron donor characteristic and M 2 is a monomer having an electron acceptor characteristic.

R ₁ and R ₂ are alkyl substituents which may be the same or different.

And n is from 1 to 10,000.

According to one embodiment of the present invention, single-walled carbon nanotubes can be selectively separated using a conjugated polymer.

In addition, SWNTs having different diameters and chirality can be separated by designing the conjugated polymer.

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

FIG. 1 is a schematic diagram of a conjugated polymer according to an embodiment of the present invention for selectively separating single-walled carbon nanotubes.
2 is a flowchart illustrating a method for selectively separating single-walled carbon nanotubes using a conjugated polymer according to an embodiment of the present invention.
3 is an absorption wavelength graph of a single-walled carbon nanotube named HiPco according to an embodiment of the present invention.
4 is an absorption wavelength graph of a single-walled carbon nanotube designated Rn-220 according to an embodiment of the present invention.
FIG. 5 is a graph of absorption wavelengths of single-walled carbon nanotubes named HiPco and Arc discahge combined with PC12TV18T conjugated polymer according to an embodiment of the present invention.
FIG. 6 is a Raman spectroscopy graph of single-walled carbon nanotubes named HiPco according to an embodiment of the present invention. FIG.
FIG. 7 is a Raman spectroscopy graph of a single-walled carbon nanotube designated Rn-220 according to an embodiment of the present invention. FIG.
8 is a table showing characteristics of various single-walled carbon nanotubes.
9 is a graph illustrating the performance of a transistor using a semiconducting single-walled carbon nanotube separated by a conjugated polymer according to an embodiment of the present invention as a conductive material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" (connected, connected, coupled) with another part, it is not only the case where it is "directly connected" "Is included. Also, when an element is referred to as " comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

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

A conjugated polymer is a polymer having a conjugated molecule as a monomer, and one embodiment of the present invention provides a conjugated polymer of a continuous vinyl group.

FIG. 1 is a schematic diagram of a conjugated polymer according to an embodiment of the present invention for selectively separating single-walled carbon nanotubes.

The conjugated molecule for selective separation of single walled carbon nanotubes according to an embodiment of the present invention is represented by the following formula 1,

[Chemical Formula 1]

In Formula 1, M1 is a monomer having an electron donor characteristic.

For example, the M1 may be selected from the group consisting of thienylenevinylene (TV) or dasieno [3,2-b: 2 ', 3'-d] : 2 ', 3'-d] thiophene, DTT).

M2 is a monomer having the characteristics of an electron acceptor.

For example, the M2 may be selected from the group consisting of Diketopyrrolopyrole (DPP) or (E) - [3,3'-binaphthalenylidene] -2,2'- -bindolinylidene] -2,2'-dione).

The conjugated polymer in which the conjugate system is formed can be formed by arranging the M1 having the electron donor characteristic and the M2 having the electron acceptor characteristic in succession.

For example, when a conjugated molecule containing a vinyl group is substituted, a conjugated polymer having an increased conjugate length can be formed. This allows the hexagonal carbon bonds to have strong π-π interactions with the carbon nanotubes produced by the graphene sheet, which is a flat sheet.

Wherein R ₁ and R ₂ are alkyl substituents which may be the same or different.

For example, the alkyl substituent may include hydrogen, an unbranched alkyl group having 1-18 carbon atoms, a branched alkyl group having 1-18 carbon atoms, or an alkyl halide having 1-18 carbon atoms.

The alkyl substituent functions to separate and separate the carbon nanotubes.

At this time, depending on the structure of the alkyl substituent, the interaction with the single wall carbon nanotubes is changed, so that single wall carbon nanotubes selectively having different diameters and chirality can be separated according to the structure of the alkyl substituent.

At this time, the separation yield of the semiconductor carbon nanotube and the metal carbon nanotube in the solvent can be determined by controlling the density of the alkyl substituent.

This is because the polarity changes depending on the density difference of the alkyl substituent, and the semiconductor carbon nanotube having the relatively low polarity remains in the supernatant in the toluene solvent having low polarity.

 And n is an integer of 1 to 10,000.

Here, the conjugated polymer may be used as a separating agent for separation of single-walled single-walled carbon nanotubes (SWNTs). Also, the conjugated polymer selectively separating the single-walled carbon nanotubes and the single-walled carbon nanotubes separated therefrom can be used for manufacturing the transistor.

Manufacturing example

A conjugated polymer for selective separation of single walled carbon nanotubes according to an embodiment of the present invention was prepared.

Scheme 1

In the preparation examples of the present invention, as shown in Reaction Scheme 1, the compound of [1] is alkylated using a Grignard reagent represented by R-MgBr to produce the compound of [2]. R 1 may be the same or different and may be independently selected from the group consisting of hydrogen, unbranched alkyl group having 1-18 carbon atoms, branched alkyl group having 1-18 carbon atoms, Lt; / RTI > alkyl halide. Next, the compound of [2] is subjected to bromination using NBS to produce the compound of [3]. Next, the compound of [3] is substituted with an aldehyde group by bromine using Mg and DMF to give the compound of [4]. The compound of [4] is then subjected to a Mac-head coupling reaction in the presence of TiCl4, Zn and THF to yield the compound of [5]. Then, the compound of [5] is reacted with n-BuLi, SnMe ₃ Cl and a THF solvent to produce a thienylenevinylene (TV) compound of [6].

Scheme 2

As shown in Reaction Scheme 2, the thiophene compound of [7] is subjected to a coupling reaction with PdCl ₂ (PhCN) ₂ , KF, AgNO ₃ and DMSO solvent to produce the bithiophene compound of [8].

Scheme 3

As shown in Reaction Scheme 3, polymerization is carried out using the thienylenevinylene (TV) compound of [6] and the bithiophene compound of [8] as monomers to produce the polymer of [9]. When R ₁ and R ₂ are hydrogen, this is referred to as PCTV 18T, and when R ₁ and R ₂ are C ₁₂ H ₂₅ , this is referred to as PC ₁₂ TV 18T.

2 is a flowchart illustrating a method for selectively separating single-walled carbon nanotubes using a conjugated polymer according to an embodiment of the present invention.

Referring to FIG. 2, a method for selectively separating single-walled carbon nanotubes using a conjugated polymer includes a step (S100) of preparing a mixed solution of a single-walled carbon nanotube and a conjugated polymer, (S200), centrifuging the mixed solution in which the single-walled carbon nanotubes are dispersed (S300), extracting the supernatant of the centrifuged mixed solution (S400), separating the conjugated polymer Removing the conjugated polymer in a mixed solution of semiconducting SWNTs (S500), and dispersing semiconducting SWNTs in the supernatant (S600).

In this case, the step (S100) of preparing a mixed solution of the single-walled carbon nanotube and the conjugated polymer is performed such that the ratio of the single-walled carbon nanotube to the conjugated polymer is 1: 1-5.

At this time, the step (S200) of dispersing the single-walled carbon nanotubes of the mixed solution is characterized in that it is dispersed through sonication.

The sound wave processing functions to disperse single wall carbon nanotubes, which are gathered through vibrations generated by sound waves, into individual pieces. Of the single-walled carbon nanotubes thus dispersed, only the semiconducting SWNT is surrounded by the conjugated polymer.

In step S300 of centrifuging the mixed solution in which the single-walled carbon nanotubes are dispersed, the semiconducting SWNT combined with the conjugated polymer having a relatively low polarity in the low polarity solvent remains in the supernatant, Is coagulated and precipitated, separating the semiconducting SWNT from the metallic SWNT.

At this time, the centrifugal separation step (S300) of the mixed solution in which the single-walled carbon nanotubes are dispersed is repeated twice or more as necessary.

At this time, the step (S400) of extracting the supernatant of the centrifuged mixed solution is characterized in that the conjugated polymer, the semiconducting SWNT and the residual conjugated polymer are dissolved in the supernatant, and the metallic SWNT is precipitated.

At this time, removing the conjugated polymer in the mixed solution of the conjugated polymer of the supernatant and the semiconducting SWNT (S500) may be performed using a centrifugal separator.

For example, the step of removing the conjugated polymer (S500) comprises: centrifuging the supernatant obtained in the step (S400) of extracting the supernatant of the centrifuged mixed solution at 320,000 g, and removing the conjugated polymer dissolved in a toluene solvent And repeating the process of precipitating semiconducting SWNT 2-3 times.

Since most of the metallic SWNT is removed in step S400 of extracting the supernatant of the centrifuged mixed solution, the material precipitated in the step of removing the conjugated polymer (S500) is a semiconducting SWNT.

At this time, the step S600 of dispersing the semiconducting SWNTs in the supernatant may be further added if necessary. In addition, the semiconducting carbon nanotubes may be further subjected to a centrifugal force to disperse the semiconducting carbon nanotubes through a sound wave treatment do.

The step S600 of dispersing the semiconducting SWNTs in the upper layer liquid may be performed to improve the performance of the carbon nanotubes by solving the aggregation of the single wall carbon nanotubes.

Also, the step of dispersing the semiconducting SWNTs in the supernatant (S600) may be performed to enable a solution process.

Experimental Example

The selective separation of single walled carbon nanotubes using the conjugated polymer according to an embodiment of the present invention was performed and the results were analyzed.

First, a mixed solution of the conjugated polymer and carbon nanotube was prepared by dissolving it in toluene so that the ratio of conjugated polymer: SWNT = 2: 1 was 0.5 g / ml.

Next, the conjugated polymer and single-walled carbon nanotubes were dispersed by sonication at 25 ° C for one hour.

Next, the mixed solution in which the conjugated polymer and single-walled carbon nanotubes were dispersed was centrifuged four times at 85,000 g for one hour and centrifuged once at 320,000 g for twelve hours.

The supernatant of the centrifuged mixed solution was then extracted using a pipette. At this time, the semiconducting SWNT and the conjugated polymer are present in the supernatant, and the metallic SWNT is precipitated.

Finally, the supernatant was sonicated at 25 ° C for one hour to disperse the conjugated polymer and semiconducting SWNTs.

3 is an absorption wavelength graph of a single-walled carbon nanotube named HiPco according to an embodiment of the present invention.

4 is an absorption wavelength graph of a single-walled carbon nanotube designated Rn-220 according to an embodiment of the present invention.

3 to 4, compared with the absorption wavelength graph of HiPco or Rn-220 in which semiconducting and metallic single-walled carbon nanotubes are mixed, when the conjugate polymer treatment is performed, the peak is refined and the shinging toward the longer wavelength is about 100 nm Of the total. This means that the optical properties are changed due to the strong? -N interaction between the conjugated polymer and the single-walled carbon nanotube, and the semiconducting single-walled carbon nanotube is selectively separated by the conjugated polymer.

FIG. 5 is a graph of absorption wavelengths of single-walled carbon nanotubes named HiPco and Arc discahge combined with PC12TV18T conjugated polymer according to an embodiment of the present invention.

Referring to FIG. 5, it can be seen that the PC12TV18T according to an embodiment of the present invention can separate HiPco and AD (arc discharge), which are different single wall carbon nanotubes, respectively.

FIG. 6 is a Raman spectroscopy graph of single-walled carbon nanotubes named HiPco according to an embodiment of the present invention. FIG.

FIG. 7 is a Raman spectroscopy graph of a single-walled carbon nanotube designated Rn-220 according to an embodiment of the present invention. FIG.

6 to 7, the absorption of the metallic single-walled carbon nanotube (m-SWNT) before and after the separation treatment with the conjugated polymer according to the embodiment of the present invention is measured before the separation treatment (SWNT) of the semiconducting single-walled carbon nanotube (s-SWNT) is substantially similar to that of the separation process, the conjugated polymer according to an embodiment of the present invention selectively laminates the semiconducting SWNT It can be seen that the SWNT can be separated.

8 is a table showing characteristics of various single-walled carbon nanotubes.

3 to 7, the conjugated polymer according to an embodiment of the present invention was able to separate three single-walled carbon nanotubes of HiPco, Rn-220 and AD (Arc Discharge) from mixed SWNTs.

Referring to FIG. 8, it can be seen that the conjugated polymer according to an embodiment of the present invention is capable of universally separating single-walled carbon nanotubes having a diameter of 0.8 to 1.7 nm.

At this time, Rn-220 single-walled carbon nanotubes are the most commercially available materials because they are the cheapest. Accordingly, when the conjugated polymer according to one embodiment of the present invention is used, a high-purity single-walled carbon nanotube that can be used in a commercial market can be provided.

9 is a graph of a voltage-current characteristic of a transistor using a semiconducting single-walled carbon nanotube separated by a conjugated polymer according to an embodiment of the present invention as a conductive material.

9A is a diagram showing a structure of a transistor using SWNTs.

FIG. 9 (b) is an AFM (Atomic Force Microscopy) image of HiPco and RN-220, SNWTs of different diameters separated by the conjugated polymer PC12TV18T according to an embodiment of the present invention.

As a result, it can be seen that the conjugated polymer according to an embodiment of the present invention can separate SWNTs of different diameters.

FIG. 9C is a graph of a current-voltage characteristic of a conjugated polymer according to an embodiment of the present invention.

Referring to FIG. 9D, it can be seen that the higher the diameter, the better the on / off ratio characteristics of the device and the higher the charge mobility due to the lower band gap.

The bond between the carbon atoms is stronger than the bond of silicon which is the main material of the semiconductor at present and is chemically stable in the air at room temperature and has high thermal conductivity, .

Referring to FIG. 9, it can be seen that the conjugated polymer and the semiconducting SWNT separation method using the conjugated polymer according to the present invention can be effectively used for manufacturing a transistor by separating semiconducting SWNTs.

In general, it has been confirmed that the conjugated polymer according to an embodiment of the present invention can selectively separate semiconducting carbon nanotubes from carbon nanotubes in which semiconductivity and metallic carbon nanotubes are mixed.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (13)

A conjugated polymer for selective separation of single walled carbon nanotubes (SWNTs) represented by the following formula (1).
[Chemical Formula 1]

In the general formula 1, M1 and M2 is a monomer, and each M1 is an electron donor (electron donor), and M2 is characterized in that the electron acceptor (electron acceptor), and, R ₁ and R ₂ are chosen to be the same as or different from each other, And n is an integer of 1 to 10000,
Wherein the single-walled carbon nanotube comprises a semiconducting SWNT and a metallic SWNT. The method according to claim 1,
The M1 may be selected from the group consisting of Thienylenevinylene (TV), Bithiophene, thieno [3,2-b] thiophene, fluorene, : 2 ', 3'-d] thiophene (Dithieno [3,2-b: 2', 3'-d] thiophene, DTT) Polymers. The method according to claim 1,
Wherein M2 is selected from the group consisting of diketopyrrolopyrole (DPP), benzo [c] [1,2,5] thiadiazole, 1H-benzo [d] 3] triazole, 4H-cyano [3,4-c] pyrrole-4,6 (5H) -dione (4H-thieno [3,4- ) Or (E) - [3,3'-binindolinylidene] -2,2'-dione ((E) - [3,3'-biindolinylidene] -2,2'-dione) Conjugated Polymer for Selective Separation of Single Walled Carbon Nanotubes. The method according to claim 1,
Wherein the alkyl substituent comprises hydrogen, an alkyl group having 1-18 carbon atoms without branches, an alkyl group having 1-18 carbon atoms having a branch, or an alkyl halide having 1-18 carbon atoms, for selective separation of single walled carbon nanotubes Conjugated polymer. Preparing a mixed solution of a single-walled carbon nanotube (SWNT) and a conjugated polymer;
Dispersing the single-walled carbon nanotubes of the mixed solution;
Centrifuging the mixed solution in which the single-walled carbon nanotubes are dispersed; And
And extracting the supernatant of the centrifuged mixed solution,
Wherein the conjugated polymer is a conjugated polymer defined by claim 1,
And separating two or more single-walled carbon nanotubes having different diameters by using one of the conjugated polymers. 6. The method of claim 5,
Wherein the step of preparing the mixed solution of the single walled carbon nanotube and the conjugate polymer is performed such that the ratio of the single walled carbon nanotube to the conjugated polymer is 1: 1 to 5. 6. The method of claim 5,
Wherein the solvent of the mixed solution is a nonpolar solvent. 8. The method of claim 7,
Wherein the solvent is toluene. ≪ RTI ID = 0.0 > 11. < / RTI > 6. The method of claim 5,
Wherein the step of dispersing the single-walled carbon nanotubes in the mixed solution is performed by sonication. 6. The method of claim 5,
Wherein the step of centrifuging the mixed solution in which the single-walled carbon nanotubes are dispersed is repeated two or more times. 6. The method of claim 5,
Wherein the step of extracting the supernatant of the centrifuged mixed solution comprises dissolving the conjugated polymer and the semiconducting SWNT in the supernatant and precipitating the metallic SWNT. 6. The method of claim 5,
After the step of extracting the supernatant of the centrifuged mixed solution,
Further comprising the step of removing the conjugated polymer in a mixed solution of the conjugated polymer of the supernatant and the semiconducting SWNT. 11. The method of claim 10,
Wherein the step of dispersing the semiconducting SWNTs in the supernatant is carried out by sonication.

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