KR102054708B1 - Manufacturing method of metal nanowires and metal nanowires thereby - Google Patents

Abstract

The present invention relates to a method for producing metal nanowires using a coaxial co-electrospinning method and to metal nanowires produced thereby.
Metal nanowire manufacturing method according to an embodiment of the present invention, preparing a first spinning solution comprising a metal nanoparticles and a second spinning solution comprising a polymer material; One of the first spinning solution and the second spinning solution is disposed in the core portion of the double nozzle and the other in the shell portion of the double nozzle, and the first spinning solution is disposed on the substrate from the double nozzle. Co-electrospinning the spinning solution and the second spinning solution; And sintering the first spinning solution and the second spinning solution electrospun onto the substrate; It includes.
According to the metal nanowire manufacturing method of the present invention, the spinning solution is prepared using metal nanoparticles without using a reaction of a metal precursor or a reducing agent, and the shape is uniform by adopting a coaxial double electrospinning method among electrospinning methods, The surface condition is good, and metal nanowires having a high aspect ratio can be produced.

Description

Manufacturing method of metal nanowires and metal nanowires produced thereby {Manufacturing method of metal nanowires and metal nanowires thereby}

The present invention relates to a method for manufacturing a metal nanowire and a metal nanowire produced by the same, and more particularly, to a method for producing a metal nanowire using a coaxial double electrospinning method and a metal nanowire produced thereby. It is about a wire.

Nano-wires are nanostructured wire structures, ranging in size from less than 10 nm in diameter to hundreds of nm in diameter. Such nanowires have an advantage in that they can use optical properties indicating movement characteristics or polarization of electrons in a specific direction. Accordingly, nanowires are widely applied to various fields such as optical devices, transistors, touch panels, and memory devices.

In particular, the metal nanowires, which are structures made of metal single crystals, have high chemical stability, excellent electrical conductivity and thermal conductivity, and have high utility in various fields requiring electrical, optical, mechanical, and thermal characteristics. Particularly, in the case of devices using metal nanowires, they can be applied to make high-efficiency electrons, light, optoelectronics, electronic devices, bio-active molecule detection devices and catalysts that were difficult to realize in bulk devices made of conventional technologies. There is an active research on synthesis and properties.

However, research on the manufacturing method and physical properties of nano-particles (nano-particles) is quite active, whereas research on the manufacturing method of nano-wires is insufficient. Exemplary conventional methods for producing nanowires include a method of growing nanowires using a catalyst, and a method of forming nanowires using a template.

Typically, a method of growing a nanowire metal using a catalyst is used. A method of growing a nanowire using a mixture of a nanowire material and a metal as a raw material and a metal catalyst as a nucleus. Specifically, there are laser assisted catalytic growth (LCG) and vapor liquid solid (VLS) growth methods (see the prior patent document 1).

However, these methods have limitations such as the limitation of the maximum formation length of nanowires, unsuitable for mass production due to the high temperature heat treatment process, and the difficulty of controlling the precise thickness and distribution of nanowires. As a result, they are not suitable for use throughout the industry.

In order to overcome these limitations and produce nanowires in a mass production manner, an electrospinning process for producing nanowires by the action of electrostatic forces has been introduced (see Prior Patent Document 2).

According to the prior patent 2, a step of preparing a spinning solution comprising a silver precursor and a reducing agent, electrospinning using the spinning solution, and performing heat treatment in multiple stages of primary, secondary and tertiary in a predetermined temperature range It is disclosed that silver nanowires (or silver nanofibers) with high crystallinity and aspect ratios can be produced by performing the steps. That is, according to the disclosed method, electrospinning the spinning solution including the silver precursor and the reducing agent, and reacting the silver precursor and the reducing agent to produce the silver nanowires by heat treatment.

According to this method, there is an advantage that mass production is possible compared to the method of growing a nanowire using a catalyst, but it is not possible to ensure uniform reaction between the metal precursor and the reducing agent, and a single spinning method in which a metal material and a polymer material are mixed. In this case, when the polymer is removed by heat treatment, shrinkage or cracking occurs in the metal nanowires, resulting in a problem of deterioration in quality.

Metal nanowires must meet various physical properties such as uniform shape, good surface condition, high aspect ratio, etc., which requires many process steps in manufacturing, and excessive time and cost. There is a problem.

1. Korean Patent Publication No. 10-2014-0026331 (Invention name: Manufacturing method of silver nanowires and silver nanowire growth control agent) 2. Korean Patent Publication No. 10-2014-0128583 (Invention name: Manufacturing method of silver nanofiber)

The present invention has been made to solve the above problems, an object of the present invention is to provide a method for producing a metal nanowire having a uniform shape, a good surface state, and a high aspect ratio.

In addition, in the manufacture of the metal nanowires by presenting a combination of various process conditions of the electrospinning process, it is an object to provide a method for producing a higher quality metal nanowires.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

Metal nanowire manufacturing method according to an embodiment of the present invention for solving the above problems, preparing a first spinning solution comprising a metal nanoparticles and a second spinning solution comprising a polymer material; One of the first spinning solution and the second spinning solution is disposed in the core portion of the double nozzle and the other in the shell portion of the double nozzle, and the first spinning solution is disposed on the substrate from the double nozzle. Co-electrospinning the spinning solution and the second spinning solution; And sintering the first spinning solution and the second spinning solution electrospun onto the substrate; It includes.

According to another feature of the present invention, the first spinning solution may further include a solvent, a dispersant, an adhesive, and a stabilizer in addition to the metal nanoparticles.

According to another feature of the invention, the metal nanoparticles, the diameter may be in the range of 30nm to 100nm.

According to another feature of the invention, the metal nanoparticles may be silver (Ag) nanoparticles.

According to another feature of the invention, the metal nanoparticles may be included in the first spinning solution to be 40wt% to 70wt% relative to the weight of the first spinning solution.

According to another feature of the present invention, the first spinning solution may be prepared by mixing the metal nanoparticles, the solvent, the dispersant, the adhesive and the stabilizer such that the viscosity is 100 cPs to 1,000 cPs.

According to another feature of the invention, the second spinning solution may further include a solvent and water in addition to the polymer material.

According to another feature of the invention, the polymer material may be polyethylene oxide (PEO).

According to another feature of the invention, the polymer material may be included in the second spinning solution to be 4wt% to 7wt% relative to the weight of the second spinning solution.

According to another feature of the invention, the step of electrospinning, the first spinning solution to the core portion, the second spinning solution is placed in the shell portion to the first spinning solution to the second spinning solution It can be electrospun to wrap.

According to another feature of the invention, the flow rate at which the first spinning solution is radiated from the core portion may be 0.02ml / hr to 0.5ml / hr.

According to another feature of the invention, the flow rate at which the second spinning solution is radiated in the shell portion may be 1ml / hr to 5ml / hr.

According to another feature of the invention, in the electrospinning step, a voltage may be applied to the dual nozzle and the substrate such that the voltage difference between the dual nozzle and the substrate is 5kV to 10kV.

According to another feature of the present invention, a voltage may be applied to the dual nozzle and the substrate such that the voltage difference between the dual nozzle and the substrate is 7 kV.

According to another feature of the invention, in the electrospinning step, the double nozzle and the substrate may be spaced apart by a distance of 17cm to 33cm.

According to another feature of the invention, the step of electrospinning may be performed repeatedly a plurality of times.

According to another feature of the invention, the sintering step may be performed by a heat treatment for heating for a predetermined time in a predetermined temperature range.

According to another feature of the invention, the predetermined temperature range is 150 ° C to 300 ° C, the predetermined time may be 20 min to 1 hr.

According to another feature of the invention, the metal nanowires, may be manufactured to have a diameter of 500nm to 10,000nm.

According to another feature of the invention, after the step of sintering, coating or surface treatment on the substrate on which the metal nanowires are formed; It may further include.

Metal nanowires according to an embodiment of the present invention for solving the above problems, preparing a first spinning solution comprising a metal nanoparticles and a second spinning solution comprising a polymer material; One of the first spinning solution and the second spinning solution is disposed in the core portion of the double nozzle and the other in the shell portion of the double nozzle, and the first spinning solution is disposed on the substrate from the double nozzle. Co-electrospinning the spinning solution and the second spinning solution; And sintering the first spinning solution and the second spinning solution electrospun onto the substrate; It is prepared according to the metal nanowire manufacturing method comprising a.

According to the metal nanowire manufacturing method of the present invention, the spinning solution is prepared using metal nanoparticles without using a reaction of a metal precursor or a reducing agent, and the shape is uniform by adopting a coaxial double electrospinning method among electrospinning methods, The surface condition is good, and metal nanowires having a high aspect ratio can be produced.

In addition, according to the metal nanowire manufacturing method of the present invention, it is possible to manufacture a higher quality metal nanowires by controlling various process conditions of the electrospinning process throughout the manufacturing step, the electrospinning step and the sintering step of the spinning solution.

1 is a schematic flowchart illustrating a method of manufacturing a metal nanowire according to an embodiment of the present invention.
FIG. 2 is a schematic block diagram illustrating an electrospinning apparatus for manufacturing metal nanowires and a method of manufacturing metal nanowires using the apparatus.
3 is a schematic cross-sectional view showing the form of a double nozzle used in the electrospinning apparatus of FIG.
4 is a schematic perspective view illustrating a spinning solution spinning from a nozzle of the electrospinning apparatus of FIG. 2 to a substrate.
5 is a schematic perspective view showing a state in which the step of sintering is performed in the method of manufacturing a metal nanowire of the present invention.
6 is a SEM photograph showing a state in which the manufactured metal nanowires are disconnected.
7 is a SEM photograph showing a cross section of the spinning solution and the metal nanowires before and after the sintering step is performed.
8 is a graph showing the relationship between the mass loss of the spinning solution according to the sintering temperature in the step of sintering.
9 is a SEM photograph showing a state in which the adhesion force of the metal nanowires is changed according to the sintering temperature in the sintering step.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims.

References to elements or layers "on" other elements or layers include all instances where another layer or other element is directly over or in the middle of another element.

Although the first, second, etc. are used to describe various components, these components are of course not limited by these terms. These terms are only used to distinguish one component from another. Therefore, of course, the first component mentioned below may be a second component within the technical spirit of the present invention.

Like reference numerals refer to like elements throughout.

The size and thickness of each component shown in the drawings are shown for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated configuration.

Each of the features of the various embodiments of the present invention may be combined or combined with each other in part or in whole, various technically interlocking and driving as can be understood by those skilled in the art, each of the embodiments may be implemented independently of each other It may be possible to implement the association together.

Hereinafter, with reference to the accompanying drawings, it will be described in detail with respect to the manufacturing method of the metal nanowire according to an embodiment of the present invention.

1 is a schematic flowchart illustrating a method of manufacturing a metal nanowire according to an embodiment of the present invention, Figure 2 is an electrospinning apparatus for manufacturing a metal nanowire and a metal nanowire using the device A schematic block diagram illustrating the method, FIG. 3 is a schematic cross-sectional view illustrating the form of a double nozzle used in the electrospinning apparatus of FIG. 2, and FIG. 4 is a spinning solution from the nozzle of the electrospinning apparatus of FIG. 2 to the substrate. FIG. 5 is a schematic perspective view illustrating a radiated state, and FIG. 5 is a schematic perspective view illustrating a sintering step performed in the method of manufacturing a metal nanowire of the present invention.

Referring to Figure 1, the metal nanowire manufacturing method of the present invention, the step of preparing a first spinning solution containing a metal nanoparticles and a second spinning solution containing a polymer material (S100), from the double nozzle to the substrate Coaxially electrospinning the first spinning solution and the second spinning solution (S200); and sintering the first spinning solution and the second spinning solution electrospun onto the substrate (S300). Is performed.

First, as a raw material for manufacturing the metal nanowires, a first spinning solution and a second spinning solution are prepared (S100).

Here, the first spinning solution is a raw material constituting the part remaining in the form of the metal nanowire finally after all the manufacturing method of the metal nanowire of the present invention is performed.

The first spinning solution includes metal nanoparticles, a solvent, a dispersant, an adhesive, and a stabilizer.

The metal nanoparticles may preferably be silver (Ag) nanoparticles.

However, the present invention is not limited thereto, and the metal nanoparticles may include copper (Cu), cobalt (Co), scandium (Sc), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), and nickel (Ni). ), Zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), cadmium ( Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), lanthanides Elemental (lanthanide) and actinium (actinoid), silicon (Si), germanium (Ge), tin (Sn), arsenic (As), antimony (Sb), bismuth (Bi), gallium (Ga) and indium (In It may be a nanoparticle containing at least one selected from the group consisting of.

Here, the metal nanoparticles may be composed of materials having various nano shapes. Preferably, spherical nanoparticles (nanoparticles) are used, but nanowires, nanotubes, nanorods, nanowalls can be used as long as they can be electrospun through the nozzles. , Nano belts (nanobelt) and nano rings (nanoring) may include at least one selected from the group consisting of.

At this time, the metal nanoparticles, the diameter may be in the range of 30nm to 100nm. In order for the metal nanoparticles to pass through the nozzle without clogging to form metal nanowires having a diameter of 360 nm to 1000 nm, metal nano particles having a diameter in the above range are preferably used.

The solvent usable in preparing the first spinning solution is not particularly limited as long as it can dissolve metal nanoparticles, dispersants, adhesives and stabilizers. The solvent may be a polar or nonpolar solvent. The solvent may be selected from the group consisting of water, alcohols and mixtures thereof, such as water, methanol, ethanol, propanol, isopropanol, butanol, acetone, detrahydrofuran, toluene or dimethylformamide, dimethyl sulfoxide Side, N, N-dimethyl formamide, 1-methyl-2-pyrrolidone, trimethyl phosphate and mixtures thereof.

In this case, the metal nanoparticles are preferably included in the first spinning solution such that 40 wt% to 70 wt% of the weight of the first spinning solution is used. The content of the solvent, the dispersant, the adhesive agent, and the stabilizer is equal to the viscosity of the first spinning solution. It is preferable that the content is adjusted to include 100 cPs to 1,000 cPs, more preferably 650 cPs to 850 cPs.

If the content of the metal nanoparticles is less than 40wt%, or the viscosity of the first spinning solution is less than 650cPs, the breakage of the metal nanowires may not be formed to have a uniform diameter, or a breakage may occur, or the shape of the wires may be formed in the electrospinning step. It does not radiate to the spray spray problem occurs. On the other hand, when the content of the metal nanoparticles is greater than 70wt% or the viscosity of the first spinning solution is greater than 850cPs there is a fear that the nozzles are clogged when electrospun from the nozzles.

In addition, the first spinning solution may further include a viscosity modifier, and the viscosity modifier may include dextran, alginate, chitosan, guar gum, starch, carboxymethyl cellulose, hydroxy ethyl cellulose, hydroxypropyl methyl cellulose, xanthan gum. , Carboxy vinyl polymer, pectin, sodium alginate and combinations thereof.

The second spinning solution is a raw material constituting the final sintered part after all the manufacturing methods of the metal nanowires of the present invention are performed.

The second spinning solution includes a polymeric material and a solvent.

The polymeric material may preferably be polyethylene oxide (PEO) solids.

However, the polymer material is not limited thereto, and polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), polyurethane, polyetherurethane, Cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, polymethylacrylate (PMA), polyvinylacetate (PVAc), polyacrylonitrile (PAN), polyperfuryl alcohol (PPFA), polystyrene, polypropylene oxide (PPO), polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride and at least one selected from the group consisting of polyamide.

In addition, the polymer material may include a copolymer of the above-described materials, and for example, a polyurethane copolymer, a polyacryl copolymer, a polyvinylacetate copolymer, a polystyrene copolymer, a polyethylene oxide copolymer, a polypropylene oxide copolymer , And at least one selected from the group consisting of polyvinylidene fluoride copolymers.

In this case, the polymer material is preferably included in the second spinning solution to be 4wt% to 7wt% relative to the weight of the second spinning solution.

If the content of the polymer material is less than 4wt%, a breakage phenomenon occurs in which the metal nanowires are not formed to have a uniform diameter and are broken, or a problem of spray-injection occurs without spinning in the form of wires in the electrospinning step. On the other hand, when the content of the polymer material is greater than 7wt%, the nozzle may be clogged when it is electrospun from the nozzle.

The solvent usable in preparing the second spinning solution is not particularly limited as long as it can dissolve a high molecular material. The solvent may be a polar or nonpolar solvent. The solvent may be selected from the group consisting of water, alcohols and mixtures thereof, such as water, methanol, ethanol, propanol, isopropanol, butanol, acetone, detrahydrofuran, toluene or dimethylformamide, dimethyl sulfoxide Side, N, N-dimethyl formamide, 1-methyl-2-pyrrolidone, trimethyl phosphate and mixtures thereof. The water here may be deionized water.

In addition, the second spinning solution may further include a viscosity modifier, and the viscosity modifier may include dextran, alginate, chitosan, guar gum, starch, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, xanthan gum. , Carboxy vinyl polymer, pectin, sodium alginate and combinations thereof.

However, the above-described polymer material and the polymer material solution are exemplary, and the technical spirit of the present invention is not limited thereto.

The first spinning solution and the second spinning solution made of such a material are electrospun by an electrospinning apparatus. Prior to describing a specific method of coaxial double electrospinning, an electrospinning apparatus for performing electrospinning of this step will be described in detail.

Referring to FIG. 2, the electrospinning apparatus 1 includes a spinning solution tank 10, a spinning nozzle 20, an external power supply 30, and a collector substrate 40.

The spinning solution tank 10 stores the spinning solution. The spinning solution tank 10 may pressurize the spinning solution using a built-in pump (not shown) to provide the spinning solution to the spinning nozzle 20.

The spinning nozzle 20 receives the spinning solution from the spinning solution tank 10 to spin the spinning solution. The spinning nozzle 20 spins the spinning solution by the voltage applied by the external power source 30 after the spinning solution is pressurized by the pump to fill the nozzle tube therein.

Here, as the spinning nozzle 20, the double nozzle shown in FIG. 3 is used.

Referring to FIG. 3, the double spinning nozzle 20 includes a first nozzle 21 of a core part and a second nozzle 22 of a shell part. The double spinning nozzle 20 is configured such that the second nozzle 22 in the shell portion surrounds the first nozzle 21 in the core portion, and the first nozzle 21 and the second nozzle 22 are formed. It is preferable that it is a nozzle of the coaxial double structure comprised so that an axis may coincide.

The first nozzle 21 is connected with the first tank 11, and the second nozzle 22 is connected with the second tank 12. This double spinning nozzle 20 is configured such that the first spinning solution 200a and the second spinning solution 200b can be spun at the same time without being mixed with each other.

Referring again to FIG. 2, the external power supply 30 provides a voltage such that the spinning solution is radiated to the spinning nozzle 20. The voltage can vary depending on the type of spinning solution and the amount of radiation. For example, it may range from about 100 V to about 30000 V, and may be direct current or alternating current. The voltage applied by the external power source 30 can radiate the spinning solution filled in the spinning nozzle 20.

The collector substrate 40 is located under the spinning nozzle and contains the spinning solution to be spun. The collector substrate 40 may be grounded to have a voltage of 0V, which is the ground voltage, or the collector substrate 40 may have a voltage opposite to the spinning nozzle 20. Since the radiation nozzle 20 is charged to a positive voltage or a negative voltage by the external power supply 30, the radiation solution is also charged, so that a voltage difference occurs with the collector substrate 40 having a grounded or opposite voltage. do.

When a voltage is applied to the spinning nozzle 20 by the external power supply 30, the spinning solution is formed in a conical shape such as a Taylor cone at the end of the spinning nozzle 20. Due to the voltage difference, the spinning solution may be radiated to the collector substrate 40 to be accommodated. The voltage applied during electrospinning may vary depending on the type of the nanomaterial, the type of the polymer material, the type of the substrate, and the processing environment. It can be configured to apply.

In addition, the positional relationship of the radiation nozzle 20 and the collector board | substrate 40 in FIG. 2 is an illustration, and the technical idea of this invention is not limited to this. For example, unlike shown in FIG. 2, the collector substrate 40 is located above the spinning nozzle 20 and the spinning solution radiated from the spinning nozzle 20 may be spun upward, and the collector substrate 40 ) And the spinning solution which is positioned horizontally with respect to the spinning nozzle 20 and radiated from the spinning nozzle 20 may be spun in the horizontal direction.

An electrospinning method according to various arrangements of the spinning nozzle 20 and the collector substrate 40 may be included in the technical idea of the present invention. In addition, although the planar substrate was illustrated as the collector substrate 40, it is not limited to this, of course, the drum type collector which rotates about a central axis can be used.

Using this electrospinning apparatus 1, coaxial electroelectrospinning of the first spinning solution and the second spinning solution from the double spinning nozzle 20 is performed (S200).

At this time, one of the first spinning solution and the second spinning solution may be disposed in the core part of the double spinning nozzle 20 and the other in the shell part of the double spinning nozzle 20.

The arrangement of the first spinning solution and the second spinning solution may be selected depending on whether the shape of the metal nanowires to be manufactured is a rod type or a hollow type according to the manufacturing method of the metal nanowires of the present invention. Can be.

In other words, where the first spinning solution is a raw material constituting the part remaining in the form of metal nanowires after all the manufacturing method of the metal nanowires of the present invention is performed, the second spinning solution is the metal nanowires of the present invention. It is a raw material constituting the final sintered part after all the manufacturing method of the wire is performed. Therefore, in order to manufacture the rod-type metal nanowires according to the method of manufacturing the metal nanowires of the present invention, the first spinning solution is disposed in the core and the second spinning solution is disposed in the shell. On the contrary, if a hollow type metal nanowire is to be manufactured according to the method for producing a metal nanowire of the present invention, the second spinning solution is disposed in the core and the first spinning solution is disposed in the shell. This will be described in detail with reference to FIG. 5 and the sintering step to be described later.

By way of example, a specific electrospinning step will be described by arranging a rod-type metal nanowire by arranging a first spinning solution in a core and a second spinning solution in a shell, but the first spinning solution as described above. And the second spinning solution may optionally be disposed in the core part, the shell part of the double nozzle.

Referring to FIG. 4, the first spinning solution 200a including the metal nanoparticles is placed in the core of the double spinning nozzle 20, and the second spinning solution 200b is disposed in the shell of the dual spinning nozzle 20. And coaxial double electrospinning from the double spinning nozzle 20 to the substrate 100.

The substrate 100 is an object for forming metal nanowires on its surface or a member for obtaining metal nanowires, and includes glass, quartz, silicon oxide, aluminum oxide, polyimide, and polyethylene naphthalate (PEN). , Polyethylene terephthalate (PET), polymethylmethacrylate (PMMA), and polydimethylsiloxane (PDMS).

This substrate 100 is located on the collector substrate 40 of the electrospinning apparatus 1 of FIG. 2 and allows the spinning solution radiated from the double spinning nozzle 20 to be seated.

By controlling the flow rate of the first spinning solution 200a and the second spinning solution 200b and the voltage difference between the double spinning nozzle 20 and the collector substrate 40, the length and diameter of the metal nanowires to be manufactured can be controlled. Can be. This will be described with reference to Table 1 and Table 2 below and the pictures shown in FIG. 6 together.

Table 1 is a result showing the diameter distribution of the metal nanowires according to the spinning flow rate of the spinning solution in the core portion and the shell portion during the electrospinning step, Figure 6 is a SEM photograph showing the disconnected state of the manufactured metal nanowires , Table 2 is a result showing the diameter distribution of the metal nanowires according to the voltage applied to the nozzle and the substrate in the electrospinning step.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Core flow rate (ml / hr) 0.4 0.3 0.5 0.4 0.4 Shell flow rate (ml / hr) 1.5 1.5 1.5 1.4 1.6 Wire thickness (nm) 450 480 1,010 1,020 820

The flow rate at which the first spinning solution is spun at the core of the double spinning nozzle 20 is 0.02 ml / hr to 0.5 ml / hr, and the flow rate at which the second spinning solution is spun at the shell of the dual spinning nozzle 20 is 1 ml /. It is preferable that it is hr-5 ml / hr. More preferably, as shown in Table 1, the flow rate at which the first spinning solution is radiated is 0.3 ml / hr to 0.5 ml / hr, and the flow rate at which the second spinning solution is radiated at the shell portion is 1.4 ml / hr to 1.6 ml. / hr is good.

Specifically, looking at the diameter distribution graph of the metal nanowire according to the spinning flow rate shown in Table 1, the flow rate of the second spinning solution of the shell portion is 1.5ml / hr, the flow rate of the first spinning solution of the core portion is 0.5ml / hr or 0.4 It can be seen that the silver nanowires are manufactured to have a diameter of 820 nm to 1,020 nm and an average diameter of 970 nm when ml / hr. The prepared silver nanowires have a uniform diameter distribution and excellent surface condition. Among them, when the flow rate at which the first spinning solution is radiated is 0.4 ml / hr, and the flow rate at which the second spinning solution is radiated at the shell portion is 1.5 ml / hr (Example 1), the prepared metal nanowire is thin as 450 nm. It can be seen that it is produced in a uniform diameter. On the other hand, when the flow rate at which the first spinning solution is radiated is 0.3 ml / hr, and the flow rate at which the second spinning solution is radiated at the shell portion is equal to 1.5 ml / hr (Comparative Example 1), the manufactured metal nanowire is less than 450 nm. It can confirm that it thickens.

On the other hand, when the flow rate of the second spinning solution of the shell portion is gradually decreased while maintaining the flow rate of the first spinning solution of the core portion at 0.5 ml / hr, that is, the flow rate of the second spinning solution of the shell portion is 1.4 ml / hr. When gradually reduced to 1.0ml / hr, silver nanowires were observed to have a nonuniform diameter. Even reducing the flow rate of the second spinning solution of the shell portion to 1.0ml / hr, and reducing the flow rate of the first spinning solution of the core portion to 0.3ml / hr, the disconnection phenomenon of the silver nanowires as shown in FIG. It confirmed that it appeared.

Based on the experimental data, it was possible to confirm the desirable flow rate relationship between the first spinning solution and the second spinning solution radiated from the core part and the shell part of the double nozzle, and to produce metal nanowires of uniform diameter in the numerical range of the flow rate. The technical significance of this can be confirmed.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Voltage difference (kV) 7 6 8 9 Wire thickness (nm) 800 1,000 1,010 1,040

In addition, the correlation between the voltage applied to the dual spinning nozzle 20 and the collector substrate 40 and the diameter distribution of the metal nanowires will be described with reference to Table 2 above.

The voltage difference between the voltages applied to the double spinning nozzle 20 and the collector substrate 40 is preferably 5 kV to 10 kV. More preferably, the voltage difference between the voltages applied to the double spinning nozzle 20 and the collector substrate 40 is 7 kV. At this time, the flow rate of the second spinning solution of the shell portion is 1.5 ml / hr, and the flow rate of the first spinning solution of the core portion is controlled to 0.5 ml / hr.

Referring to Table 2, in the case where the voltage difference between the voltage applied to the dual spinning nozzle 20 and the collector substrate 40 is 7 kV, the diameter of the metal nanowire is 0.88 μm to 0.93 μm, that is, at an average of 800 nm (0.8 μm). It can be seen that the diameter is produced in a small and uniform state (Example 1). At this time, when the voltage difference applied to the double spinning nozzle 20 is out of the range of 7 kV (Comparative Example 1 and Comparative Example 2), it can be seen that the diameter of the metal nanowire is increased.

Based on the experimental data, it is possible to confirm the relationship between the diameter of the metal nanowires and the voltage applied to the double-spinning nozzle and the collector substrate. Significance can be confirmed.

Under the conditions of the flow rate and the applied voltage of the spinning solution described above, the double spinning nozzle 20 and the collector substrate 40 are preferably spaced apart by a distance of 17 cm to 33 cm. If the dual spinning nozzle 20 and the collector substrate 40 are spaced 17 cm or less or spaced 33 cm or more, the diameter of the spine may not be formed to the desired size or the spinning solution may not be completely seated on the substrate 100. Problems may arise.

According to the electrospinning step (S200) described above, the second spinning solution containing the polymer material surrounds the first spinning solution including the metal nanoparticles, or the first spinning solution including the metal nanoparticles is formed of the polymer material. The spinning solution structure 200c of the coaxial bilayer may be formed to surround the second spinning solution including the coaxial bilayer.

Specifically, referring to FIG. 4, the second spinning solution 200b including the polymer material is disposed to surround the first spinning solution 200a including the metal particles. In this case, the double radiated spinning solution structure 200c may be arranged on the substrate 100 to form a one-dimensional, two-dimensional or three-dimensional network structure formed by being superimposed and connected to each other.

The spinning solution structure 200c may form a one-dimensional network structure in which a plurality of linearly shaped structures are superimposed in parallel with each other and connected in one linear shape, and the plurality of linearly shaped structures have a predetermined angle to each other. Overlaid and connected to form a two-dimensional network structure connected in one planar shape, a plurality of linear-shaped structures can be overlapped and connected to each other to have a predetermined angle to form a three-dimensional network structure connected in one three-dimensional shape have. In addition, the spinning solution structure 200c may have a shape having a predetermined pattern, and may be arranged to have a mesh shape or a web shape, for example.

The spinning solution structure 200c thus formed is formed of a rod type metal nanowire or a hollow type metal nanowire by a process of selectively sintering a polymer material.

The manufacturing method of the metal nanowire of the present invention includes the step of sintering the spinning solution structure 200c electrospun on the substrate 100 (S300).

The spinning solution structure 200c is in a gel state, and the metal nanowires are produced by going through the step of sintering.

On the other hand, before the step of sintering (S300), an annealing process may be selectively performed to correct the deformation of the interior of the spinning solution structure 200c arranged on the substrate 100 and to arrange the materials homogeneously. have. Annealing may be carried out by appropriately heating the spinning solution structure 200c in a predetermined temperature range in a heat treatment manner in which it is heated to a constant temperature and then slowly cooled. By increasing the bonding force between the nanomaterials included in the spinning solution structure 200c by the annealing process, the spinning solution structure 200c can be formed of high quality metal nanowires.

Referring to FIG. 5, by sintering the spinning solution structure 200c, the second spinning material 200b including the polymer material is selectively removed.

When the second radiating material 200b is removed by the sintering process, the rod-shaped metal nanowire 300 as shown in FIG. 5A and the hollow metal nanowire 300 as shown in FIG. 5B are removed. Can be prepared.

In the step S300, the sintering method may be a thermal sintering method. Thermal sintering means sintering by melting the polymer material by heating the metal nanowires to a temperature range above the melting point. This will be described with reference to the graph or photograph shown in FIGS. 7 to 9.

7 is a SEM photograph showing a cross section of the spinning solution and the metal nanowires before and after the sintering step is performed, FIG. 8 is a graph showing the relationship between the mass loss of the spinning solution according to the sintering temperature in the sintering step, and FIG. Is a SEM photograph showing how the adhesion force of the metal nanowire is changed according to the sintering temperature in the sintering step.

FIG. 7A illustrates a cross-sectional state of the spinning solution structure 200c before sintering, and FIG. 7B illustrates a cross-sectional state of the metal nanowire 300 after sintering. It shows the result of applying heat to the spinning solution structure (200c) for about 30 minutes at about 300 ° C, it can be seen that the metal nanoparticles are melted and bonded to each other made of a mass of metal nanowires (300).

It also thermally sinters to melt the polymer material and allow the metal nanoparticles to form networking with each other. However, when a plastic substrate having a low melting point is used, the process of thermal sintering at a high temperature cannot be used, and therefore, it is necessary to pay attention to the selection of the substrate when the thermal sintering method is adopted.

Looking at the graph of Figure 8 and the photograph of Figure 9, it can be seen the temperature range of the preferred thermal sintering. Specifically, looking at the TGA graph showing the relationship between the mass loss of the spinning solution according to the sintering temperature, when the temperature of the thermal sintering is 300 ° C or more, it is confirmed that all the solvent or additive contained in the first spinning solution is lost Can be. In addition, looking at Figure 9 showing the appearance of the adhesive force when the temperature of the thermal sintering is 300 ° C or more, it can be confirmed that the phenomenon that the metal nanowires are bent along the surface curvature of the substrate.

Therefore, it can be seen that the temperature range of the thermal sintering that causes the metal nanoparticles to form networking with each other but does not cause disconnection problems is 300 ° C. or less. However, the minimum thermal sintering temperature for the metal nanoparticles to form a networking with each other is 150 ° C, the temperature range of the thermal sintering in this step (S300) is preferably 150 ° C or more and 300 ° C or less. In addition, the time for heat treatment in this temperature range is preferably 20min to 1hr.

On the other hand, the sintering method in the sintering step (S300) is not limited to the thermal sintering method, other optical sintering and chemical sintering method may be employed.

Chemical sintering means sintering in such a way that the polymer material is melted by impregnating the spinning solution structure 200c in an organic solvent in which the polymer material can be dissolved.

Here, the organic solvent may include all kinds of solvents capable of dissolving the polymer material. Organic solvents include alkanes such as hexane, aromatics such as toluene, ethers such as diethyl ether, alkyl halides such as chloroform, esters, aldehydes, ketones, amines, alcohols, amides, carboxylic acids And various materials such as water. The organic solvent is, for example, acetone, fluoroalkane, pentane, hexane, 2,2,4-triketylpentane, decane, cyclohexane, cyclopentane, diisobutylene, 1-pentene, carbon disulfide, carbon tetrachloride , 1-chlorobutane, 1-chloropentane, silylene, diisopropylether, 1-chloropropane, 2-chloropropane, toluene, tallowbenzene, benzene, bromoethane, diethyl ether, diethyl sulfide, chloroform, Dichloromethane, 4-methyl-2-propane, tetrahydrofuran, 1,2-dichloroethane, 2-butanone, 1-nitropropane, 1,4-dioxane, ethyl acetate, methyl acetate, 1-pentanol At least any one selected from the group consisting of dimethyl sulfoxide, aniline, diethylamine, nitromethane, acetonitrile, pyridine, 2-butoxyethanol, 1-propanol, 2-propanol, ethanol, methanol, ethylene glycol and acetic acid It may include one.

Light sintering uses a xenon lamp or the like to irradiate light in a desired wavelength region (or all regions) at a constant energy for 1 second to several seconds, thereby removing polymer material for a short time and forming networking of nanomaterials. Means the way.

In the optical sintering process, light pulse, on time, off time, voltage, and wavelength range are important control variables, and it is preferable that optical sintering is performed through optimization of these parameters.

Light sintering can be performed within a few seconds, so it may be repeatedly performed as needed.

According to the method of manufacturing the metal nanowires described above, the metal nanowires of the present invention may be manufactured to have a diameter of 360 nm to 10,000 nm, and preferably may have a diameter of 500 nm to 10,000 nm.

Meanwhile, the manufacturing method of the metal nanowire may further include coating or surface treatment on the substrate on which the metal nanowire is formed after the step of sintering (S300). When electrospinning is performed using a transparent substrate, this is a step for improving the visibility of the substrate on which the metal nanowires are manufactured, which may be optionally performed.

As a coating or surface treatment, a method of forming a coating layer on the metal nanowires by spraying a conductive coating solution, a silver sulfide (Ag2S) treatment, or a method of blackening the metal nanowires by plasma treatment may be employed. have.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

One … Electrospinning apparatus
10... Spinning solution tank
11. First tank
12... Second tank
20... Double spinning nozzle
21. First nozzle
22. Second nozzle
30. External power
40…. Collector board
100... Board
200... Spinning solution
200a... First spinning solution
200b... Secondary spinning solution
200c... Spinning solution structure
300... Metal nanowires

Claims (21)

Preparing a first spinning solution including metal nanoparticles and a second spinning solution including a polymer material;
One of the first spinning solution and the second spinning solution is disposed in the core portion of the double nozzle and the other in the shell portion of the double nozzle, and the first spinning solution is disposed on the substrate from the double nozzle. Co-electrospinning the spinning solution and the second spinning solution; And
Sintering the first spinning solution and the second spinning solution electrospun onto the substrate; A method of manufacturing a metal nanowire, including. According to claim 1,
The first spinning solution,
In addition to the metal nanoparticles, the method further comprises a solvent, a dispersant, an adhesive and a stabilizer. According to claim 1,
The metal nanoparticles,
Method of producing a metal nanowire, the diameter of which belongs to the range of 30nm to 100nm. According to claim 1,
The metal nanoparticles,
A method for producing a metal nanowire, which is a silver (Ag) nanoparticle. According to claim 1,
The metal nanoparticles,
It is included in the first spinning solution to be 40wt% to 70wt% relative to the weight of the first spinning solution, the manufacturing method of the metal nanowires. The method of claim 2,
The first spinning solution,
The metal nanowires are prepared by mixing the metal nanoparticles, the solvent, the dispersant, the adhesive and the stabilizer so that the viscosity is 100 cPs to 1,000 cPs. According to claim 1,
The second spinning solution,
In addition to the polymer material, the method of manufacturing a metal nanowire further comprises a solvent and water. According to claim 1,
The polymer material,
Method for producing a metal nanowire, which is polyethylene oxide (PEO). According to claim 1,
The polymer material,
It is included in the second spinning solution to be 4wt% to 7wt% relative to the weight of the second spinning solution, the manufacturing method of the metal nanowires. According to claim 1,
The electrospinning step,
Disposing the first spinning solution on the core and the second spinning solution on the shell to electrospin the first spinning solution to surround the second spinning solution. The method of claim 10,
Flow rate at which the first spinning solution is radiated from the core portion is 0.02ml / hr to 0.5ml / hr, the manufacturing method of the metal nanowire. The method of claim 10,
The flow rate at which the second spinning solution is radiated in the shell portion is 1ml / hr to 5ml / hr. According to claim 1,
In the step of electrospinning,
And applying a voltage to the double nozzle and the substrate such that the voltage difference between the double nozzle and the substrate is 5 kV to 10 kV. The method of claim 13,
And applying a voltage to the double nozzle and the substrate such that the voltage difference between the double nozzle and the substrate is 7 kV. According to claim 1,
In the step of electrospinning,
The double nozzle and the substrate are disposed spaced apart by a distance of 17cm to 33cm, metal nanowire manufacturing method. According to claim 1,
The electrospinning step,
Method of manufacturing a metal nanowire, which is performed by repeating a plurality of times. According to claim 1,
The sintering step,
Method of manufacturing a metal nanowires, which is performed by a heat treatment for heating for a predetermined time in a predetermined temperature range. The method of claim 17,
The preset temperature range is 150 ° C to 300 ° C,
The predetermined time is 20 minutes to 1hr, method of manufacturing a metal nanowire. According to claim 1,
The metal nanowires,
Method of producing a metal nanowire, which is prepared to have a diameter of 500nm to 10,000nm. According to claim 1,
After the sintering step,
Surface treatment on the substrate on which the metal nanowires are formed; Further comprising, metal nano wire manufacturing method. The metal nanowire manufactured by the manufacturing method of the metal nanowire of any one of Claims 1-20.

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