KR102152632B1 - Nanowire ink - Google Patents

Abstract

Nanowire ink according to the embodiment, a solvent; Nanowires dispersed in the solvent; And a connecting compound connecting the solvent and the nanowire.

Description

Nano wire ink {NANOWIRE INK}

The embodiment relates to a nanowire ink.

Metal nanowires have been the subject of major research interest in the development of nanoelectrical and nanoelectronic devices because of their nanoconductivity and atomic-scale electrical contact.

In particular, since silver (Ag) among various metals exhibits high electrical conductivity and thermal conductivity compared to other metals, studies on silver nanowires have been actively conducted. Silver also has a wide range of commercial applications, and the change to a one-dimensional structure is expected to be expanded to various applications through high aspect ratio and control of well refined crystal planes. Therefore, various methods for synthesizing silver nanowires have been developed, and their structures and properties have been studied.

Silver nanowires can be synthesized to have a high aspect ratio, and thus can be used as a transparent electrode, and have the advantage of being coated by a coating method such as a simple bar coating or roll coating. In addition, since it is chemically stable and has the advantage of being bent after coating, it can replace the existing transparent ITO electrode or use it as a printing metal wiring, attracting attention as an electrode material that can replace the existing electrode.

However, since these silver nanowires have a property of being settled in a solution state and thus it is difficult to disperse, there is a problem that it is difficult to apply them to the manufacture of electrodes.

The embodiment is to provide a nanowire with improved dispersibility.

Nanowire ink according to the embodiment, a solvent; Nanowires dispersed in the solvent; And a connecting compound connecting the solvent and the nanowire.

The nanowire ink according to the embodiment includes a nanowire, a connecting compound, and a solvent.

In addition, the linking compound includes a hydrophilic group and a hydrophobic group at both ends.

Accordingly, the hydrophilic group of the linking compound is chemically bonded to the nanowire having hydrophilicity, and the hydrophobic group of the linking compound is chemically bonded to the solvent having hydrophobicity.

Accordingly, the nanowire having hydrophilicity may be uniformly dispersed by the connecting compound in the solvent having hydrophobicity. In addition, the surface of the nanowires is modified by the connection compound, so that aggregation of the nanowires may be prevented in the solvent.

Therefore, the nanowire ink according to the embodiment has improved dispersion stability in the solvent, and thus precipitation of the nanowire in the solvent can be prevented.

1 is a view showing an aqueous dispersion containing nanowires.
2 is a flowchart illustrating a method of manufacturing a nanowire ink according to an embodiment.
3 is a view showing a nanowire ink according to an embodiment.
FIG. 4 is an enlarged view of part A of FIG. 3.
5 is a diagram illustrating a touch panel to which a nanowire is applied according to an embodiment.
6 is a diagram illustrating a mobile terminal to which a nanowire is applied according to an embodiment.

In the description of the embodiments, each layer (film), region, pattern, or structure is “on” or “under/under” the substrate, each layer (film), region, pad or patterns. The description that "is formed in" includes both directly or through another layer. The criteria for the top/top or bottom/bottom of each layer will be described based on the drawings.

In the drawings, the thickness or size of each layer (film), region, pattern, or structure may be modified for clarity and convenience of description, so the actual size is not entirely reflected.

Hereinafter, a nanowire ink according to an embodiment will be described with reference to FIGS. 1 to 4. 1 is a view showing an aqueous dispersion including nanowires, FIG. 2 is a process flow diagram illustrating a method of manufacturing a nanowire ink according to an embodiment, and FIG. 3 is a view showing a nanowire ink according to an embodiment And FIG. 4 is an enlarged view of part A of FIG. 3.

1 to 4, the nanowire ink according to the embodiment includes a solvent 40, a nanowire 10 dispersed in the solvent 40, the solvent 40, and the nanowire 10. It includes a connecting compound (30) to connect.

The solvent 40 may include a hydrophobic solvent. In detail, the solvent 40 may include a compound represented by Formula 1 below.

[Formula 1]

For example, the solvent 40 may be 2-amino-1-butanol. That is, the solvent 40 may include a compound having a hydrophobic group at one end.

The nanowire 10 may be a metal nanowire having conductivity. In detail, the nanowire 10 may include a silver (Ag) nanowire.

The nanowire 10 may include a hydrophilic group. The nanowire 10 may be added to the solvent 40 and dispersed in the solvent 40.

The linking compound 30 is added in the solvent 40. The connecting compound 30 serves to connect the solvent 40 and the nanowire 10 in the solvent 40.

That is, the linking compound 30 may include both a hydrophilic group and a hydrophobic group. Accordingly, it is added in the solvent 40, the hydrophilic group of the linking compound 30 may be bonded to the nanowire 10, and the hydrophobic group of the linking compound 30 may be bonded to the solvent 40. .

Accordingly, the nanowire 10 and the solvent 40 may be bonded to each other by the connection compound 30. That is, the connecting compound 30 serves as a link connecting the nanowire 10 and the solvent 40.

The linking compound 30 may have both hydrophobic and hydrophilic properties including a hydrophobic group and a hydrophilic group at both ends. The linking compound 30 may be represented by Formula 2 below.

[Formula 2]

For example, the linking compound 30 may include 3,6,9-Trioxadecanoic acid (TODA).

Since the nanowire 10 can be well bonded to the solvent 40 by the connection compound 30, it is not aggregated in the solvent 40, and dispersibility can be improved.

Hereinafter, a method of manufacturing a nanowire ink according to an embodiment will be described with reference to FIGS. 1 to 4.

Referring to Figure 2, the nanowire ink manufacturing method according to the embodiment includes the steps of preparing an aqueous dispersion containing nanowires (ST10), adding a solvent to the aqueous dispersion and mixing (ST20), in the aqueous dispersion And adding and mixing the linking compound (ST30) and separating the supernatant (ST40).

In the step (ST10) of preparing an aqueous dispersion containing nanowires, nanowires are prepared. In detail, silver nanowires can be prepared. The silver nanowire may be manufactured in the following manner.

Hereinafter, the method of manufacturing the silver nanowire will be briefly described.

The silver nanowires include heating a solvent, adding a capping agent to the solvent, adding a catalyst to the solvent, adding a metal compound to the solvent, adding a room temperature solvent to the solvent, and nano It may include the step of purifying the wire. All of these steps are not essential and some steps may not be performed depending on the manufacturing method, and the order of each step may be changed. Each of the above-described steps will be described in more detail as follows.

In the step of heating the solvent, the solvent is heated to a reaction temperature suitable for formation of silver nanowires.

In this case, polyol may be used as a solvent. These polyols can help form silver nanowires by serving as a solvent for mixing other materials and as a mile reducing agent. Examples of such polyols include ethylene glycol (EG), propylene glycol (PG), glycerin, glycerol, and glucose. The reaction temperature can be variously adjusted in consideration of the type and characteristics of the solvent and metal compound.

Subsequently, in the step of adding a capping agent to the solvent, a capping agent that induces wire formation is added to the solvent. If the reduction for nanowire formation is performed too quickly, metals are aggregated and it is difficult to form a wire shape. This capping agent serves to prevent aggregation by appropriately dispersing substances in the solvent.

Various materials can be used as the capping agent, for example, polyvinylpyrrolidine (PVP), polyvinyl alcohol (PVA), cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC), and polyacrylamide (PAA). ) Can be used.

Subsequently, in the step of adding the catalyst to the solvent, a sea salt, a purified salt, or a halogen metal such as AgCl, PtCl ₂ , PdCl ₂ , or AuCl ₃ is added as a catalyst. These catalysts are provided with various metal or halogen elements and serve to promote the reaction of forming a seed for forming a silver nanowire and forming a metal nanowire.

Subsequently, in the step of adding the metal compound to the solvent, a reaction solution is formed by adding the metal compound to the solvent.

In this case, the metal compound may be dissolved in a separate solvent and added to a solvent to which a capping agent and a catalyst are added. As a separate solvent, the same material as the first used solvent or a different material may be used. In addition, the metal compound may be added after a certain time has passed after adding the catalyst. This is to stabilize the temperature to an appropriate reaction temperature.

Here, the metal compound is a compound containing a metal for forming a metal nanowire desired to be manufactured. In the case of forming a silver nanowire, AgCl, AgNO ₃ or KAg(CN) ₂ may be used as a metal compound.

When the metal compound is added to the solvent to which the capping agent and catalyst are added, a reaction occurs and formation of metal nanowires begins.

Subsequently, in the step of adding a solvent at room temperature to the reaction solution, a solvent at room temperature is additionally added to the solvent in which the reaction has started. As the solvent at room temperature, the same material or a different material as the first used solvent may be used. For example, as a solvent at room temperature, polyols such as ethylene glycol and propylene glycol may be used.

The temperature of the solvent in which the reaction has started may be increased during the reaction by continuously heating to maintain a constant reaction temperature.As described above, the temperature of the solvent is temporarily lowered by adding a solvent at room temperature to the solvent in which the reaction has started. You can keep the temperature more constant.

The temperature of the solvent in which the reaction has started may be increased during the reaction by continuously heating to maintain a constant reaction temperature.As described above, the temperature of the solvent is temporarily lowered by adding a solvent at room temperature to the solvent in which the reaction has started. You can keep the temperature more constant.

The step of adding the solvent at room temperature may be performed once or several times in consideration of the reaction time and the temperature of the reaction solution.

Subsequently, in the step of purifying the nanowires, the silver nanowires are purified and collected from the reaction solution.

More specifically, when acetone, which is a non-polar solvent rather than water, is added to the reaction solution, the silver nanowires are precipitated in the lower portion of the solution by the capping agent remaining on the surface of the metal nanowires. This is because the capping agent dissolves well in a solvent, but does not dissolve in acetone, but aggregates and precipitates. Thereafter, when the upper layer solution is discarded, part of the capping agent and formed nanoparticles are removed.

When distilled water is added to the remaining solution, silver nanowires and metal nanoparticles are dispersed, and when acetone is added further, silver nanowires are precipitated and metal nanoparticles are dispersed in the upper layer solution. Thereafter, when the upper layer solution is discarded, a part of the capping agent and metal nanoparticles formed by aggregation are removed. This process is repeated to collect the silver nanowires and then store them in distilled water. By storing the silver nanowires in distilled water, it is possible to prevent re-aggregation of the metal nanowires.

As shown in FIG. 1 in the same manner as described above, an aqueous dispersion containing silver nanowires can be prepared. That is, the aqueous dispersion may include distilled water 10 and nanowires 10 mixed with the distilled water 10.

Subsequently, in the step of adding and mixing a solvent to the aqueous dispersion (ST20), a solvent 40 is added and mixed to the aqueous dispersion. In this case, the solvent 40 may be a hydrophobic solvent having a hydrophobic group.

For example, the solvent 40 may be 2-amino-1-butanol having a hydrophobic group.

The solvent 40 may be included in an amount of about 27% by weight to about 29% by weight based on the total nanowire ink to be manufactured.

Subsequently, in the step of adding and mixing the linking compound to the aqueous dispersion (ST30), the linking compound 30 is added to and mixed with the aqueous dispersion. That is, the connecting compound 30 is added and mixed to a solution in which the aqueous dispersion and the solvent 40 are mixed.

The linking compound 30 may be a compound having both a hydrophilic group and a hydrophobic group. The connecting compound 30 is bonded to the nanowire 10 having hydrophilicity and the solvent 40 having hydrophobicity, respectively. Accordingly, the nanowire 10 and the solvent 40 may be connected by the connection compound.

The linking compound 30 may be 3,6,9-Trioxadecanoic acid (TODA) having both a hydrophilic group and a hydrophobic group.

The connection compound 30 may be included in an amount of about 0.07% to about 0.08% by weight based on the total nanowire ink to be manufactured. When the connecting compound 30 is included in an amount of less than 0.07% by weight, the bonding strength between the nanowire 10 and the solvent 40 may be weakened, so that the nanowire may not be properly dispersed in the solvent 40. In addition, when the linking compound 30 is contained in excess of 0.08% by weight, the linking compound may be supersaturated to precipitate the linking compound.

Subsequently, in the step of removing the supernatant (ST40), the supernatant is separated from a solution in which the aqueous dispersion including silver nanowires, the solvent 40, and the connecting compound 30 are mixed. At this time, before separating the supernatant, a non-polar solvent may be further added to the mixed solution. In detail, acetone may be added to the mixed solution to precipitate the silver nanowires in the lower layer direction.

Accordingly, only distilled water and a small amount of solvent remain in the supernatant of the mixed solution, and the nanowire 10, the connecting compound 30, the solvent 40, and acetone remain in the lower layer of the mixed solution. After removing the supernatant, only the lower layer may be separated to finally prepare a nanowire ink.

In addition, the nanowire ink may further include a thickener, a surfactant, a crosslinking agent, or an antifoaming agent to improve properties of the nanowire ink.

For example, when preparing the nanowire ink, dispersion stability may be further improved by adding a thickener, and polyvinyl, polyacrylic acid, maleic anhydride copolymer, etc. may be used as the thickener.

In addition, when the silver nanowire ink is coated on the substrate by adding a surfactant during the preparation of the nanowire ink, the wettability with the substrate may be improved. Etc. can be used.

In addition, by adding a crosslinking agent in the preparation of the nanowire ink, the hardness of the film formed by coating the silver nanowire ink can be improved, and as the crosslinking agent, 4,4-diphenylmethane, disorcinate, epoxy silane, etc. may be used. I can.

In addition, when the nanowire ink is coated by adding a defoaming agent during the manufacture of the nanowire ink, the generation of bubbles may be suppressed, and as the defoaming agent, a mineral oil defoaming agent or a silicone defoaming agent may be used.

3 and 4, the bonding relationship between the nanowire 10, the connecting compound 30, and the solvent 40 in the nanowire ink is shown.

That is, the linking compound 30 includes both a hydrophilic group 31 and a hydrophobic group 32. Accordingly, the hydrophilic group 31 of the connecting compound 30 is chemically bonded with the nanowire 10 having hydrophilicity, and the hydrophobic group 32 of the connecting compound 30 is the solvent 40 having hydrophobicity. Chemically binds with

Accordingly, the nanowire 10 having hydrophilicity may be uniformly dispersed by the connecting compound 30 in the solvent 40 having hydrophobicity. In addition, since the surface of the nanowire 10 is modified by the connection compound 30, it is possible to prevent the nanowires from being aggregated in the solvent 40.

Therefore, the nanowire ink according to the embodiment has improved dispersion stability in the solvent, and thus precipitation of the nanowire in the solvent can be prevented.

Hereinafter, the present invention will be described in more detail through experimental examples. However, the experimental examples are only for illustrating the present invention, and the present invention is not limited thereto.

Experimental example

An aqueous dispersion of 50 ml of silver nanowires was prepared. At this time, about 0.5% to 1% by weight of silver nanowires was included in the 50 ml of the aqueous dispersion.

Then, about 20 ml of 2-amino-1-butanol was added to the aqueous dispersion, followed by mixing for about 1 minute.

Then, about 50 µl of 3,6,9-Trioxadecanoic acid (TODA) was added to the aqueous dispersion, followed by mixing for about 1 minute.

Then, about 100 ml of acetone was added to the aqueous dispersion and mixed for about 1 minute, and then the supernatant was removed and the lower layer was separated to prepare a silver nanowire ink.

Subsequently, the silver nanowire ink was left to observe whether or not precipitation of the silver nanowire occurred.

result

Even if the silver nanowire ink according to the embodiment was left for about 15 days or more, precipitation of the silver nanowire ink did not occur.

The nanowire ink according to the embodiment may prevent the silver nanowires from agglomeration or precipitation in the solvent by improving the dispersion stability of the silver nanowires in the solvent.

5 and 6 are diagrams illustrating a touch panel and a mobile terminal to which nanowire ink is applied according to an embodiment.

Referring to FIG. 5, the nanowire ink according to the embodiment may be applied to a touch panel.

The touch panel may include a substrate 100, a sensing electrode 210, a wiring electrode 220, a protective layer 300, an adhesive layer 400, and an LCM module D. In this case, the sensing electrode 210 may be formed by applying the nanowire ink according to the embodiment on the substrate 100.

Further, referring to FIG. 6, the mobile terminal 1000 may include an effective area AA and a non-effective area UA. The effective area AA may sense a touch signal by a touch such as a finger, and a command icon pattern part and a logo may be formed in the ineffective area.

The mobile terminal 1000 may include an electrode for sensing a touch signal therein. Such an electrode may be formed by applying the nano Wyeong ink according to the embodiment.

That is, the nanowire ink according to the embodiment may be applied to various display devices such as the touch panel and mobile terminal.

Features, structures, effects, and the like described in the above description are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Accordingly, contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiments have been described above, these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention pertains are illustrated above within the scope not departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications that are not available are possible. For example, each component specifically shown in the embodiments can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (10)

menstruum;
Nanowires dispersed in the solvent; And
Including a connecting compound connecting the solvent and the nanowire,
One end and the other end of the linking compound have different polar groups,
One end of the connection compound is connected to the nanowire, and the other end of the connection compound is connected to the solvent,
One end of the linking compound has a hydrophilic group,
The other end of the linking compound has a hydrophobic group,
The connecting compound is a nanowire ink represented by the following formula 1
[Formula 1]

delete delete The method of claim 1,
The solvent is a nanowire ink containing a hydrophobic group The method of claim 4,
The solvent is a nanowire ink represented by Formula 2 below.
[Formula 2]

The method of claim 5,
The nanowire ink is a nanowire ink containing silver (Ag). The method of claim 6,
The connecting compound is a nanowire ink containing 0.07% by weight to 0.08% by weight based on the total nanowire ink. The method of claim 6,
The solvent is a nanowire ink containing 27% to 29% by weight based on the total nanowire ink. The method of claim 1,
The nanowire ink is a nanowire ink further comprising a non-polar solvent. The method of claim 1,
The solvent includes 2-amino-1-butanol,
The linking compound is a nanowire ink containing 3,6,9-Trioxadecanoic acid (TODA),

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