KR102120377B1 - Metal nanowire and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a metal nanowire capable of improving economic efficiency and productivity by using a carbon nanostructure double-functionalized with an amine group and a carboxylic acid as a template.

Description

Metal nanowire and its manufacturing method{METAL NANOWIRE AND MANUFACTURING METHOD THEREOF}

The present invention relates to a method of manufacturing a metal nanowire capable of improving economic efficiency and productivity by using a carbon nanostructure double-functionalized with an amine group and a carboxylic acid as a template.

Metal nanowires, which are structures made of single crystals of metal, have high chemical stability, excellent electrical conductivity and thermal conductivity, and are highly useful in various fields requiring electrical, optical, mechanical, and thermal properties.

Metal nanowires must have various properties such as uniform shape, good surface condition, and high aspect ratio. To this end, a number of process steps are required during manufacturing, and there are problems such as long time. come.

As a metal nanowire, silver (Ag) nanowire is mainly used. This is because silver salt is limitedly selected for a complicated manufacturing process that requires several steps among various metal precursors, and it is generally used that is limited to silver nitrate (AgNO ₃ ). Except for this, satisfactory properties or yields are not obtained, and the burden of rising manufacturing costs is high. Copper is used as another metal because it has a high degree of oxidation, but there is a problem in that a post-treatment process for removing a surface oxide film must be additionally performed when manufacturing nanowires.

Metal nanowires are mainly synthesized on the basis of the crystallographic selective chemical reduction method in a polyol solution. However, the production cost is high and the reaction is very sensitive in the synthetic process, which limits the practical application.

Therefore, it is possible to reduce the manufacturing cost, and it is based on an excellent low-cost metal material to simplify the process, but it is not limited to the selective chemical reduction method of the crystal direction, and research and development of the manufacturing method of the metal nanowire is easier. It is necessary.

1) Korean Registered Patent No. 10-1465467 (2014.11.20.)

In order to solve the above problems, an object of the present invention is to provide a method of manufacturing a metal nanowire capable of improving productivity by simplifying a process while dramatically reducing manufacturing costs.

In addition, an object of the present invention is to provide a metal wire capable of realizing a synergistic effect of electrical and optical properties such as high conductivity and high light transmittance by utilizing carbon nanotubes as a template.

The present invention for achieving the above object

(a) reacting a carbon nanotube-containing solution containing a carbon nanotube, an amine compound, and an acid anhydride to produce an amidated carbon nanotube,

(b) ultrasonicating the aqueous dispersion of the amidated carbon nanotubes, water-soluble polymer and water, and

(c) mixing the sonicated amidated carbon nanotubes as a template, mixing the sonicated amidated carbon nanotubes, a metal precursor and a solvent under an inert atmosphere, and reacting with a reducing agent.

It provides a method of manufacturing a metal nanowire using a carbon nanotube template comprising a.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the acid anhydride of step (a) may be a polycyclic aromatic cyclic acid anhydride. In this case, the polycyclic aromatic cyclic acid anhydride is any one selected from pyrene-based cyclic acid anhydrides, chrysene-based cyclic acid anhydrides, perylene-based cyclic acid anhydrides, triphenylene-based cyclic acid anhydrides, and coronene-based cyclic acid anhydrides. Or it may be a mixture of two or more.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the water-soluble polymer of step (b) is any one selected from polyacrylic acid, polymethacrylic acid, carboxymethyl cellulose and salts thereof, or It may be a mixture of two or more. In this case, the water-soluble polymer may have a weight average molecular weight of 1,000 to 20,000 g/mol.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the carbon nanotube may be a multi-walled carbon nanotube.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, step (a) may further include washing and drying by reacting the solution followed by centrifugation.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, step (b) may further include washing and drying by reacting the aqueous dispersion with centrifugation.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, mixing under an inert atmosphere in step (c) may be carried out at 110 to 150°C.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, in step (c), the metal precursor comprises C2 to C24 linear or branched aliphatic of at least one carboxyl group, It may be a carboxylic acid salt of a metal derived from an ester compound that is an aliphatic ring or aromatic carboxylic acid or a derivative thereof.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the reducing agent in step (c) is selected from the group consisting of hydrazine-based, hydride-based, sodium phosphate-based and ascorbic acid Can be any one or a mixture of two or more.

The manufacturing method of the metal nanowire according to the present invention can significantly reduce the manufacturing cost, and simplifies the process, thereby dramatically improving productivity, which is an economical advantage.

Figure 1 shows a scanning electron micrograph (SEM: 100,000 times) of a metal nanowire prepared on a synthesized carbon nanotube template according to an embodiment of the present invention.
Figure 2 shows a scanning electron micrograph (SEM: 30,000 times) of a metal nanowire prepared on a synthesized carbon nanotube template according to an embodiment of the present invention.
Figure 3 shows the X-ray diffraction pattern (XRD) of the metal nanowires prepared on the synthesized carbon nanotube template according to an embodiment of the present invention.

Hereinafter, a preferred embodiment of the method for producing a metal nanowire using the carbon nanotube template of the present invention will be described in detail. However, this is not intended to limit the protection scope limited by the claims. In addition, technical terms and scientific terms used in the description of the present invention have meanings that are commonly understood by those of ordinary skill in the art to which this invention belongs, unless otherwise defined.

The inventors of the present invention utilize a carbon nanostructure having a double functionalized surface with an amine group and a carboxylic acid as a template, and sonicating the aqueous dispersion containing the double surface functionalized carbon nanostructure and a water-soluble polymer to metal precursor. The present invention was completed by discovering that it is possible to provide a method of manufacturing a metal nanowire using a carbon nanotube template that can simplify the process and significantly reduce costs through a reduction reaction using a compound.

A method of manufacturing a metal nanowire using a carbon nanotube template according to the present invention comprises the steps of (a) reacting a carbon nanotube-containing solution containing a carbon nanotube, an amine-based compound and an acid anhydride to produce an aminated carbon nanotube. ,

(b) ultrasonicating the aqueous dispersion of the amidated carbon nanotubes, water-soluble polymer and water, and

(c) using the sonicated amidated carbon nanotube as a template, and mixing the sonicated amidated carbon nanotube, a metal precursor, and a solvent under an inert atmosphere, followed by reacting with a reducing agent.

In the present invention, step (a) is a production step of an aminated carbon nanotube, and in the present invention, the aminated carbon nanotube means a carbon nanotube whose surface is functionalized with an amine group.

The aminated carbon nanotube is prepared by reacting a carbon nanotube-containing solution containing a carbon nanotube, an amine compound, and an acid anhydride.

In the present invention, the carbon nanotube is not particularly limited, but is preferably a single-walled carbon nanotube (SWCNT; single-walled carbon nanotube), a double-walled carbon nanotube (DWCNT; double-walled carbon nanotube) and a multi-walled carbon nanotube. (MWCNT; multi-walled carbon nanotube) may be any one or two or more selected from. More preferably, the multi-walled carbon nanotube is good for synthesizing the composite material according to the present invention because it is structurally more stable and has a longer wall thickness, and is economical in terms of cost reduction of the material. At this time, the carbon nanotubes can be used without being greatly limited in length, diameter, and density.

The amine-based compound is for introducing an amine group, and can be used without limitation as long as it is easy to introduce an amine group by reacting with an acid anhydride. More preferably, a diamine-based compound containing two amine groups is used. The diamine-based compound may include an aromatic diamine and an aliphatic diamine, for example, the aromatic diamine may be ρ-phenylenediamine, and the like, and the aliphatic diamine may be alkylenediamine such as ethylenediamine, propylenediamine, butylenediamine, or ρ-. And cycloalkanediamines such as cyclohexanediamine.

In the present invention, the acid anhydride is not particularly limited, but preferably, a polycyclic aromatic cyclic acid anhydride may be used to more easily introduce an amine group on the surface of the carbon nanotube. The polycyclic aromatic cyclic acid anhydride allows the polycyclic aromatic compound to be easily adsorbed on the surface of the carbon nanotube by π-π interaction with the carbon nanotube, and prevents defects in the carbon nanotube while surfaced with an amine group. There is an advantage that can realize a synergistic effect that can be modified.

The polycyclic aromatic cyclic acid anhydride is not particularly limited, but may include a cyclic acid anhydride group for introducing a plurality of benzene rings and amine groups. Preferably, to improve the adsorption between carbon nanotubes and polycyclic aromatic cyclic acid anhydrides, it may contain 4 or more benzene rings, more preferably 4 to 10 benzene rings. For example, the polycyclic aromatic cyclic acid anhydride includes pyrene cyclic acid anhydride, chrysene cyclic acid anhydride, perylene cyclic acid anhydride, and triphenylene cyclic acid anhydride. And a coronene cyclic acid anhydride.

The carbon nanotube-containing solution may mix a carbon nanotube, an amine-based compound, and anhydride with methylene chloride. At this time, methylene chloride is to improve the solubility of organic molecules and dispersibility of carbon nanotubes, and is not necessarily limited to methylene chloride, and can be used without limitation as long as it can be used as a substitute.

The mixed solution is subjected to sonication. The ultrasonic treatment is capable of functionalizing the surface of the carbon nanotube with an amine group through dispersion of reactants by ultrasonic vibration.

The carbon nanotube-containing solution is not particularly limited, but may be made of 0.1 to 5% by weight of carbon nanotubes, 1 to 10% by weight of amine compounds, and 0.1 to 5% by weight of acid anhydride. When the above range is satisfied, the phenomenon that carbon nanotubes aggregate or precipitate does not occur and the reaction can be carried out smoothly.

In one embodiment for the production of aminated carbon nanotubes, the carbon nanotube-containing solution is mixed with methylene chloride, followed by ultrasonic treatment to make a dispersion solution, followed by further stirring. Subsequently, a precipitate is obtained through centrifugation, and redispersed again with water to obtain a precipitate again through centrifugation. The precipitate is redispersed with methanol and centrifuged again to obtain a precipitate. The centrifugal separation process is not particularly limited, but may be repeated, and preferably performed at about 10,000 rpm for 15 minutes or twice. The final obtained precipitate was dried at room temperature for 24 hours using a vacuum oven.

In the present invention, step (b) is a step of ultrasonically mixing the aqueous dispersion using a water-soluble polymer. An aqueous dispersion mixed with a water-soluble polymer and water is prepared using the aminated carbon nanotube prepared in the step (a), and ultrasonically centrifuged to obtain a precipitate. At this time, the ultrasonicated aqueous dispersion is mixed with an alcohol compound of C ₁ to C ₄ , but the volume ratio of ethanol and the aqueous dispersion is not particularly limited, but is preferably 1.5:1 to 1:1.5. It is better to be close to 1:1. Preferably, the precipitate may be obtained by centrifuging the precipitate twice using ethanol as a solvent.

At this time, the water-soluble polymer is for aggregation or growth of metal particles, and is not limited, but may be used without limitation as long as it contains carboxylic acid. Specifically, it may be any one or a mixture of two or more selected from polyacrylic acid, polymethacrylic acid, carboxymethyl cellulose and salts thereof. Preferably, the water-soluble polymer may have a dissociating group present in the polymer chain, thereby dissolving and dissolving in water. Dissociation groups present in the polymer chain include carboxylate groups (-COO-), sulfonate groups (-SO ₃ -), sulfate groups (-OSO ₃ -), phosphate groups (-OPO ₃ -), and phosphonate groups (-PO ₃ -) and the like, but is not necessarily limited thereto. In addition, metal cations such as sodium, ammonium cations, amine cations, etc. may be included as cations that form salts by combining with the dissociating group.

In the present invention, a more preferable water-soluble polymer may be sodium polyacrylate salt.

The water-soluble polymer is not particularly limited, but may preferably have a weight average molecular weight (Mw) of 1,000 to 20,000 g/mol. When the above range is satisfied, it is possible to smoothly generate metal nanowires, and to realize excellent performance in physical properties, conductivity, and mechanical properties of the manufactured carbon nanotube-metal nanowires.

In the present invention, the aqueous dispersion is not particularly limited, but is preferably 0.05 to 0.3% by weight of an aminated carbon nanotube, 0.01 to 0.1% by weight of a water-soluble polymer, and 99.94 to 99.6% by weight of water. When the amount of the water-soluble polymer is insufficient compared to the amidated carbon nanotube, it does not sufficiently function as a carboxylic acid, and when the aminized carbon nanotube in the aqueous dispersion exceeds the above range, dispersibility is poor and uniform carboxylic acid functionalization is difficult .

Further, it is more preferable that the aqueous dispersion has a pH of 5 or more. This is to improve the metal nanowire formation yield during the reduction reaction of the metal from the metal precursor, a base may be added to adjust the pH. NaOH, KOH, triethylamine and the like can be used as the base in the solution.

In the present invention, step (c) is a step of manufacturing a metal nanowire by reducing metal from a metal precursor on a carbon nanotube template.

The aminated carbon nanotube sonicated with the water-soluble polymer is mixed with a metal precursor and a solvent. Mixing is performed under an inert atmosphere, and when mixing is sufficiently achieved, a reducing agent is added and reacted. At this time, the mixing is preferably carried out at 110 to 150 ℃. In addition, the reaction time is not particularly limited, but is preferably carried out for about 1 to 30 minutes, 3 to 10 minutes. After the reaction is completed, the reaction product is obtained as a precipitate precipitated by centrifugation. At this time, the solvent used for centrifugation is not particularly limited, but toluene may be preferably used.

In the present invention, the metal precursor may be used in various forms including organic acid salts, inorganic acid salts or halides of any one metal selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof. Preferably, it may be a carboxylic acid salt of a metal derived from an ester compound that is a C ₂ to C ₂₄ straight-chain or branched aliphatic, aliphatic ring, or aromatic carboxylic acid or derivative thereof containing at least one carboxyl group. . In one embodiment, the metal precursor includes metal acetate, metal benzoate, metal lactate, metal citrate, metal cyclohexanebutyrate, metal ethylhexanoate, metal trifluoroacetate, metal heptafluorobutyrate, and the like. have. Preferably metal acetate can be used.

A more preferred metal precursor in the present invention may be copper acetate. Copper suffers from oxidation problems and, when forming nanostructures, is more susceptible to oxidation problems due to the ratio of surface area per volume. Due to these problems, it was not easy to apply copper in the field of metal nanowires. On the other hand, unlike silver or gold, copper has a characteristic of being easily reduced due to its low reduction potential energy, so in the present invention, copper is used. Compared to silver, it is possible to manufacture metal nanowires at a lower cost, thereby realizing an excellent economic effect.

As the metal precursor, a solution in which an acid capable of anion substitution is dissolved may be used. As an example, when using metal acetate, nitric acid, which is a stronger acid than COOCH _{3, which} is a pair acid of an anion (COOCH ₃ ⁻ ) included in the precursor, may be used. That is, by allowing the strong base of the strong acid to replace the anion of the metal precursor, a metal reduction reaction is possible even when a metal precursor having low solubility in a solvent is used.

In the present invention, the reducing agent is used to reduce the metal to the metal form, and may be any one or a mixture of two or more selected from the group consisting of hydrazine-based, hydride-based, sodium phosphate-based and ascorbic acid. It may be one or two or more selected from hydrazine-based reducing agents including hydrazine, hydrazine anhydride, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate, and phenylhydrazine. Further, in addition to the hydrazine-based reducing agent, a hydride-based compound, more preferably, a borohydride containing tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, sodium borohydride, etc. Hydride-based reducing agents can be used. In addition, one or more of sodium phosphate-based reducing agent and ascorbic acid may be selected and used, but the present invention is not limited thereto.

The following will be described as an example for a detailed description of the present invention, the present invention is not limited to the following examples.

Hereinafter, the physical properties of the present invention were measured as follows.

(Example 1)

Multi-walled carbon nanotube (MWCNT) [Applied Carbon Nano Technology Co. Ltd, A-Tube-AM97, carbon content 97% by weight] 1.4g, perylene-3,4,9,10-tetracarboxylic dianhydride (PTD) 0.35g, ethylene diamine ) Mix 14mL and 70mL of triethylamine in 350mL of methylene chloride and make dispersion solution through sonication for 1 hour. After further stirring for 24 hours, centrifugation (10,000 rpm, 15 minutes) yields a precipitate. The precipitate is redispersed using water as a solvent, and then centrifuged again to obtain a precipitate. After redispersing the precipitate using methanol as a solvent, the process of centrifugation to obtain the precipitate is repeated twice. The final obtained precipitate was dried in a vacuum oven (25° C.) for 24 hours to obtain an amine-treated multi-walled carbon nanotube.

0.006 g of 35 wt% polyacrylic acid sodium salt (Mw: 15,000 g/mol) was added to 13.313 g of distilled water, and then 0.02 g of amine-treated multi-walled carbon nanotube (MWCNT) was added. Mixing is carried out to make a dispersion solution. The dispersion solution and ethanol are mixed in a 1:1 volume ratio, and then centrifuged to obtain a precipitate. For washing, after redispersing the precipitate using ethanol as a solvent, centrifuging and repeating the process twice to obtain the precipitate, the final precipitate obtained is dried in a vacuum oven (25°C) for 24 hours and post-treated with polyacrylic acid. One amine-treated multi-walled carbon nanotube is obtained.

58.902 g of octylamine, 0.02 g of amine-treated multiwall carbon nanotubes post-treated with polyacrylic acid, 2.511 g of oleic acid and 1.038 g of copper acetate are mixed in an inert gas atmosphere. . After heating the reactor to 130° C., phenylhydrazine was injected and reacted for 5 minutes, and then the reactant was extracted through centrifugation and washed with toluene to prepare a synthesized copper nanowire.

1 and 2 show a scanning electron micrograph (SEM, 100,000 / 30,000 times) of the metal nanowires prepared on the carbon nanotube template synthesized in Example 1, having a diameter of about 50 nm and a length of 20 µm. It can be seen that the metal nanowires prepared on the phosphorus carbon nanotube template are formed.

In addition, Figure 3 shows the X-ray diffraction pattern (XRD) of the metal nanowires prepared on the carbon nanotube template, and it can be confirmed that copper nanowires were uniformly coated on the surface of the double functionalized carbon nanotubes. It was confirmed that a thin oxide film was present on the surface of the copper metal layer due to the presence of insignificant copper oxide.

(Example 2)

Instead of using polycyclic aromatic cyclic acid anhydrides as acid anhydrides, cyclobutane-1,2,3,4-tetrcarboxylic dianhydride (CBDA), 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 4,4' It was carried out in the same manner as in Example 1, except that -oxydiphthalic dianhydride (ODA) was used. As a result, it can be confirmed that a metal nanowire is formed on the carbon nanotube template.

(Example 3)

It was carried out in the same manner as in Example 1, except that sodium carboxymethylcellulose (Aquaali DL-40, Nihon Shokubai Co., Ltd.) was used instead of using sodium polyacrylate salt. As a result, it can be confirmed that a metal nanowire is formed on the carbon nanotube template.

(Comparative Example 1)

58.902 g of octylamine, 0.02 g of multi-walled carbon nanotubes, 2.511 g of oleic acid and 1.038 g of copper acetate are mixed in an inert gas atmosphere. After heating to 130° C., phenylhydrazine is injected and reacted for 5 minutes. The synthesized metal nanowires were extracted through centrifugation, and washed twice using toluene as a solvent. As a result, no metal nanowire was formed on the carbon nanotube template.

(Comparative Example 2)

Multi-walled carbon nanotube (MWCNT) 1.4g, perylene-3,4,9,10-tetracarboxylic dianhydride (PTD) 0.35g, ethylene diamine ) Mix 14mL and 70mL of triethylamine in 350mL of methylene chloride and make dispersion solution through sonication for 1 hour. After further stirring for 24 hours, centrifugation (10,000 rpm, 15 minutes) yields a precipitate. The precipitate is redispersed using water as a solvent, and then centrifuged again to obtain a precipitate. After redispersing the precipitate using methanol as a solvent, the process of centrifugation to obtain the precipitate is repeated twice. The final obtained precipitate was dried in a vacuum oven (25° C.) for 24 hours to obtain an amine-treated multi-walled carbon nanotube.

58.902 g of octylamine, 0.02 g of amine-treated multi-walled carbon nanotubes, 2.511 g of oleic acid and 1.038 g of copper acetate are mixed in an inert gas atmosphere. After heating up to 130 degrees, phenylhydrazine is injected and reacted for 5 minutes. The synthesized metal nanowires were extracted through centrifugation, and washed twice using toluene as a solvent. As a result, no metal nanowire was formed on the carbon nanotube template.

As described above, the present invention has been described by a limited embodiment, but this is provided only to help a more comprehensive understanding of the present invention, and the present invention is not limited to the above embodiments, and general knowledge in the field to which the present invention pertains Various modifications and variations can be made by those who have this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and should not be determined, and all claims that are equivalent or equivalent to the scope of the claims as well as the claims to be described later belong to the scope of the spirit of the invention. .

Claims (10)

(a) reacting a carbon nanotube-containing solution containing 0.1 to 5% by weight of carbon nanotubes, 1 to 10% by weight of amine compounds, and 0.1 to 5% by weight of polycyclic aromatic cyclic acid anhydrides, centrifuging and drying By, the step of producing a carbon nanotube having an amine group on the surface,
(b) A composite having a double functionalization of surfaces with amine groups and carboxylic acids by ultrasonically treating an aqueous dispersion of 0.05 to 0.3% by weight of carbon nanotubes having an amine group on the surface, 0.01 to 0.1% by weight of a water-soluble polymer, and water. Manufacturing steps and
(c) using the complex as a template, and mixing the complex, a metal precursor and a solvent under an inert atmosphere, and adding a reducing agent to react,
The water-soluble polymer is polyacrylic acid, polymethacrylic acid, carboxymethyl cellulose and any one or two or more mixtures selected from salts thereof, the method of manufacturing a metal nanowire using the complex.
According to claim 1,
The polycyclic aromatic cyclic acid anhydride is any one or two selected from pyrene-based cyclic acid anhydride, chrysene-based cyclic acid anhydride, perylene-based cyclic acid anhydride, triphenylene-based cyclic acid anhydride and coronene-based cyclic acid anhydride Method of manufacturing a metal nanowire using the composite, which is the above mixture.
delete According to claim 1,
The water-soluble polymer is characterized in that the weight average molecular weight of 1,000 to 20,000g / mol, the method of manufacturing a metal nanowire using the composite.
According to claim 1,
The carbon nanotube is a multi-walled carbon nanotube, characterized in that, the method of manufacturing a metal nanowire using the composite.
delete According to claim 1,
The step (b) further comprises drying after reacting the aqueous dispersion with centrifugation, and then manufacturing the metal nanowires using the complex.
According to claim 1,
In step (c), mixing under an inert atmosphere is carried out at 110 to 150° C., a method of manufacturing a metal nanowire using the composite.
According to claim 1,
In the step (c), the metal precursor is a carboxylic acid salt of a metal derived from an ester compound that is a C2 to C24 linear or branched aliphatic, aliphatic ring, or aromatic carboxylic acid or derivative thereof containing at least one carboxyl group. Characterized in that, the method of manufacturing a metal nanowire using the composite.
According to claim 1,
In the step (c), the reducing agent is any one or two or more mixtures selected from the group consisting of hydrazine-based, hydride-based, sodium phosphate-based, and ascorbic acid, and the method for producing metal nanowires using the complex.

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