KR20210043280A - Preparing method and direct writing method of metal nanoparticle using ac-driven atmospheric pressure plasma - Google Patents

Abstract

One embodiment of the present invention relates to a method for preparing a metal nanoparticle and an apparatus for preparing the metal nanoparticle, wherein the apparatus comprises: an electrolyte including a metal ion; a reduction reaction tank including a plasma generation unit; and an oxidation reaction tank including an oxidizing electrode. In the apparatus, the method comprises the following steps of: applying AC voltage to the plasma generation unit to generate an AC-driven atmospheric pressure plasma; and performing a reduction reaction between the metal ion and the electrode supplied from the AC-driven atmospheric pressure plasma to form the metal nanoparticle.

Description

Manufacturing method and direct recording method of metal nanoparticles using AC-driven atmospheric pressure plasma {PREPARING METHOD AND DIRECT WRITING METHOD OF METAL NANOPARTICLE USING AC-DRIVEN ATMOSPHERIC PRESSURE PLASMA}

A method for producing metal nanoparticles using an AC-driven atmospheric pressure plasma and a direct recording method are provided.

In the modern world, nanotechnology is being applied throughout our lives, such as home appliances, medical care, and food. Nanotechnology refers to a technology using a material having a size or structure of 1 to 100 nm, and various methods for preparing nanomaterials required for such nanotechnology are being studied.

A method used to prepare a nanomaterial, a metal nanoparticle, is a metal vacuum vaporization method or a metal ion reduction method. The metal vacuum vaporization method uses the phenomenon of forming metal nanoparticles by gradually condensing vaporized metal atoms on a cold substrate and agglomerating them. The metal ion reduction method reduces metal atoms by reducing metal ions using a reducing agent. It is a method using the phenomenon of gathering together to form nanoparticles. Among them, the metal ion reduction method is mainly used to manufacture metal nanoparticles because of its simple method. However, the reducing agent used to reduce the metal ions is very harmful to the environment, and after synthesizing the nanoparticles, there is a problem that additional costs are incurred when a cleaning step is performed to remove harmful substances generated after the use of the reducing agent.

In order to solve this problem, research on a method of manufacturing nanoparticles according to a method called electrochemical plasma has been actively conducted in recent years. Electrochemical plasma is a source of electrons, ions, and reactive substances, and electrons supplied through the plasma can enable electrochemical reactions of metal substances, and metal ions are reduced by electrons supplied through the plasma, resulting in nanoparticles. Can be manufactured. In the case of a nanoparticle manufacturing method using such an electrochemical plasma, a nanomaterial is manufactured by replacing a reduction electrode with plasma among two solid electrodes (reduction electrode and oxidation electrode) used in conventional electrochemistry.

Meanwhile, in relation to the plasma driving method, a DC-driven atmospheric pressure plasma having a current flow from plasma to liquid has been widely studied.

A method for producing metal nanoparticles and a method for recording metal nanoparticles according to an embodiment of the present invention is for utilizing atmospheric pressure plasma driven by alternating current.

A method for producing metal nanoparticles and a method for recording metal nanoparticles according to an embodiment of the present invention is for promoting a reduction reaction of metal ions.

In addition to the above problems, embodiments according to the present invention may be used to achieve other tasks not specifically mentioned.

A method for producing metal nanoparticles according to an embodiment of the present invention is an apparatus for producing metal nanoparticles including a reduction reaction tank including an electrolyte solution containing metal ions and a plasma generation unit, and an oxidation reaction tank including an oxidation electrode, And generating an AC-driven atmospheric pressure plasma by applying an AC voltage to the plasma generator, and forming metal nanoparticles by reducing metal ions and electrons supplied from the AC-driven atmospheric pressure plasma.

Here, as the RMS current of the AC-driven atmospheric pressure plasma increases, the reaction rate of the reduction reaction increases.

As the voltage applied to the plasma generating unit increases, the effective current of the AC-driven atmospheric pressure plasma may increase.

As the frequency of the AC power applied to the plasma generating unit increases, the effective value current of the AC-driven atmospheric pressure plasma may increase.

The metal may include gold (Au).

The method for recording metal nanoparticles according to an embodiment of the present invention includes preparing a fiber mat including SBS and PF-108, immersing the fiber mat in a metal precursor solution containing metal ions, and forming the fiber mat. AC-driven atmospheric pressure plasma generated by drying, dropping deionized water on the fiber mat to form a fiber mat absorbed with deionized water, and applying an alternating voltage to the plasma generating part of the fiber mat absorbed with deionized water And forming a metal nanoparticle pattern by exposure to the metal ion to reduce the metal ion.

Based on the total mass of the fiber mat, the content of PF-108 may be 0.1 to 30% by weight.

As the content of PF-108 increases, the deionized water absorption rate of the fiber mat absorbed with deionized water may increase.

As the content of PF-108 increases, the density of the metal nanoparticles generated in the step of forming the metal nanoparticle pattern may increase.

In the step of preparing the fiber mat, a solution containing SBS, PF-108, DMF, and THF may be electrospun to form a fiber mat.

The metal may contain gold (Au), and the metal precursor solution may be an alcohol solution containing gold ions.

Between the step of forming the fiber mat in which the deionized water is absorbed and the step of forming the metal nanoparticle pattern, the step of removing excess deionized water may be further included.

In the step of forming the metal nanoparticle pattern, the pattern may be formed by exposing a portion of the fiber mat in which the deionized water is absorbed to an AC-driven atmospheric pressure plasma.

In the step of forming the fiber mat in which the deionized water is absorbed, a filter or paper may be disposed on the fiber mat to prevent evaporation of the deionized water.

The filter may be a hydrophilic polytetrafluoroethylene (PTFE) filter.

The method of manufacturing metal nanoparticles and recording method of metal nanoparticles according to an exemplary embodiment of the present invention may utilize an atmospheric pressure plasma driven by alternating current, and may promote a reduction reaction of metal ions.

1 is a view showing an apparatus for manufacturing metal nanoparticles according to an embodiment.
FIG. 2 (a) is a photograph showing an example of the apparatus for manufacturing metal nanoparticles of FIG. 1, (b) is a TEM image of metal nanoparticles manufactured through a reduction reaction for about 90 minutes, and (c) is It is a graph showing the UV-Vis absorbance spectrum for confirming the formation of metal nanoparticles.
3 are graphs showing UV-Vis absorbance spectra according to an input voltage, a frequency, and a grounding type.
FIG. 4 is a graph showing a change in intensity of a peak at 530 nm in the UV-Vis absorbance spectrum of FIG. 3.
5 are graphs showing TEM images and particle size distribution of particles of metal nanoparticles according to plasma exposure time. (a) and (e) are when plasma exposure time is 30 minutes, (b) and (f) are 45 minutes, (c) and (g) are 60 minutes, and (d) and (h) are 90 minutes Indicates the time.
6 is a diagram illustrating a method of recording metal nanoparticles according to an embodiment.
7 are images showing a direct recording process according to an embodiment.
8 shows SEM images of an electrospun fiber mat containing (a) 0, (b) 2, (c) 4 and (d) 6% of PF-108, respectively.
9 shows the result of AT-FTIR (FT/IR-6100, Jasco) spectrum of the fiber mat of FIG. 8(d).
10 is a graph showing the absorption rate of ethanol and water according to the content of PF-108 in the fiber mat according to the embodiment.
11 are photographs showing a direct recording process using an AC-driven atmospheric pressure plasma on a fiber mat according to an embodiment.
12 are photographs showing a change in contact angle with time for about 20 μl of deionized water of a fiber mat according to an embodiment.
13 are photographs showing a change in contact angle with time for about 20 μl of ethanol of a fiber mat according to an embodiment.
14A is a diagram showing a direct recording process using an AC-driven atmospheric pressure plasma according to an embodiment, and (b) to (d) are when the fiber mat contains SBS and does not contain PF-108. High-resolution optical and SEM photographs of the fiber mat with direct recording, (e) to (g) are high-resolution optics of the fiber mat with direct recording when the fiber mat contains SBS and about 2 wt% of PF-108 Pictures and SEM pictures are shown.
FIG. 15A is a diagram showing a direct recording process using an AC-driven atmospheric pressure plasma according to an embodiment, (b) is a high-resolution optical picture of a fiber mat in which the direct recording is made, and (c) is an SEM picture.

With reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and the same reference numerals are used for the same or similar components throughout the specification. In addition, in the case of a well-known technology, a detailed description thereof will be omitted.

In the drawings, the thicknesses are enlarged in order to clearly express various layers and regions. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where the other part is "directly above", but also the case where there is another part in the middle. On the other hand, when a part is said to be "right above" another part, it means that there is no other part in the middle. Conversely, when a part such as a layer, film, region, plate, etc. is said to be "below" another part, this includes not only the case where the other part is "directly below", but also the case where there is another part in the middle. On the other hand, when a part is said to be "right below" another part, it means that there is no other part in the middle.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

Since AC-driven atmospheric pressure plasma is not spatially constrained or constrained, it can be suitable for localized plasma-induced chemical reactions, and plasma-induced chemical reactions at the gas-liquid interface as well as the gas-solid (polymer thin film) interface. May also be suitable. In addition, AC-driven atmospheric pressure plasma can be applied to direct recording to form patterned metal nanoparticles in a single step. Therefore, the AC-driven atmospheric pressure plasma according to the embodiment can be usefully applied in various situations such as mass production of metal nanoparticles by plasma-liquid interaction or high resolution direct recording patterning by plasma-solid interface. have.

1 is a view showing an apparatus for manufacturing metal nanoparticles according to an embodiment.

Hereinafter, a method of manufacturing a metal nanoparticle according to an embodiment will be described with reference to FIG. 1.

The method of manufacturing metal nanoparticles includes metal nanoparticles including a reduction reactor 110 including an electrolyte solution 114 including metal ions and a plasma generation unit 118, and an oxidation reactor 130 including an oxidizing electrode. In the manufacturing apparatus 100 of, the step of generating an AC-driven atmospheric pressure plasma by applying an AC voltage to the plasma generating unit 118, and supplied from the AC-driven atmospheric pressure plasma with metal ions. And forming metal nanoparticles by reducing electrons.

The apparatus 100 for manufacturing metal nanoparticles includes a reduction reaction tank 110 and an oxidation reaction tank 130, and a plasma generation unit 118 disposed in the reduction reaction tank 110 performs the function of a cathode, and , In the oxidation reaction tank 130, an electrolyte solution containing metal ions and an oxide electrode immersed in the electrolyte are positioned. The oxidizing electrode may be, for example, a platinum (pt) foil.

An electrolyte solution 114 containing metal ions is also located in the reduction reactor 110, and plasma is generated between the interface between the plasma generating unit 118 and the electrolyte solution 114, and electrons can be supplied from the plasma to the electrolyte solution 114. have.

The plasma generating unit 118 is connected to a high voltage AC, and includes an internal electrode disconnected from the external environment by using a narrow glass tube. The helium (He) gas flow is connected to the glass tube and can be controlled by a mass flow controller (MFC).

Here, the metal may include, for example, gold (Au). The electrolyte solution 114 of the reduction reactor 110 may be a metal precursor solution, and the metal ions included in the electrolyte solution 114 may be, for example, gold ions. The metal precursor for supplying metal ions may be, for example, HAuCl ₄ or KAuCN ₂ , but is not limited thereto.

In the reduction reactor 110, the metal ions may undergo a reduction reaction with electrons supplied from the plasma to become metal nanoparticles.

Here, the root mean square (RMS) current of the AC-driven atmospheric pressure plasma can be directly proportional to the reaction kinetics of the reduction reaction, and as the RMS current of the AC-driven atmospheric pressure plasma increases, the reduction reaction The reaction rate of can be increased. When the RMS current increases, a high flux of electrons reaches the surface of the electrolyte solution, thereby increasing the reaction rate of the reduction reaction.

As the voltage applied to the plasma generating unit 118 increases, the RMS current of the AC-driven atmospheric pressure plasma may increase. In addition, as the frequency of the AC power applied to the plasma generating unit 118 increases, the RMS current of the AC-driven atmospheric pressure plasma may increase.

6 is a diagram illustrating a method of recording metal nanoparticles according to an embodiment.

Referring to FIG. 6, the method of recording metal nanoparticles includes i) SBS (poly(styrene-block-butadiene-block-styrene)) and PF-108 (poly(ethylene glycol)-block-poly(propylene glycol)- Preparing a fibrous mat 210 containing block-poly (ethylene glycol)), ii) immersing the fiber mat 210 in a metal precursor solution 212 containing metal ions, iii ) Drying the fiber mat 210, iv) dropping deionized water (DI water) on the fiber mat 210 to form a fiber mat in which deionized water is absorbed, and v) Metal nanoparticle pattern by exposing the fiber mat 210 absorbed with deionized water to an AC-driven atmospheric pressure plasma generated by applying an AC voltage to the plasma generating unit 218 to reduce metal ions (pattern) is formed.

The method of writing metal nanoparticles according to the embodiment is a direct writing method, and a pattern of a specific shape made of metal nanoparticles may be formed. Since the spatial resolution of the plasma can be easily reduced to the nanoscale, this direct recording method is applicable to all fields requiring metal nanoparticle patterning.

First, a step of preparing the fiber mat 210 is performed.

In the step of preparing the fiber mat 210, the fiber mat may be a water-insoluble mat, and includes an SBS material. SBS is a hard thermoplastic elastomer composed of mid-block polystyrene and polybutadiene at both ends. Based on the total mass of the fiber mat 210, SBS may be included in about 9 to 20% by weight.

SBS shows high alcohol (ethanol, etc.) absorption.

PF-108 can help fiber mats absorb and retain deionized water. In the method of recording metal nanoparticles according to the embodiment, deionized water plays an important role in forming metal nanoparticles by greatly improving diffusibility of electrons supplied from plasma and mobility of metal ions. Due to PF-108, the absorption rate of deionized water of the fiber mat can be greatly increased, and by promoting the reduction reaction of metal ions in a later step, the density of metal nanoparticles can be greatly increased in the metal nanoparticle pattern formation step. , The formed pattern can be more vivid and clear.

Based on the total mass of the fiber mat 210, the content of PF-108 may be 0.1 to 30% by weight, more specifically 0.1 to 30% by weight. Within this range, excellent elasticity and flexibility of the fiber mat 210 may be secured, and a clear metal nanoparticle pattern may be formed at the same time.

PF-108 is an amphiphilic block copolymer containing about 82.2% of hydrophilic PEG and about 17.8% of hydrophobic poly(propylene oxide) (PPO), and exhibits high water absorption. Accordingly, as the content of PF-108 increases, the deionized water absorption rate of the fiber mat absorbed with deionized water may increase.

The fiber mat 210 may be manufactured by electrospinning a solution containing SBS, PF-108, DMF (dimethylformamide) and THF (N,N-dimethylformamide). Here, the volume ratio of DMF and THF may be 3:1.

The fiber mat 210 may be a non-woven fibrous mat. The PPO portion of PF-108 is a hydrophobic intermediate block exhibiting excellent miscibility with hydrophobic SBS, and the two large end blocks composed of PEG can contribute to moisture absorption.

The fiber mat 210 according to the embodiment has excellent elasticity and flexibility, and excellent mechanical performance.

Subsequently, the step of immersing the fiber mat 210 in the metal precursor solution 212 containing metal ions is performed. For example, the immersion time may be 20 minutes to 1 hour.

The metal may include gold (Au), for example. The metal precursor solution 212 may be an alcohol solution containing gold ions, for example, an ethanol solution containing _{HAuCl 4.}

In this step, the fiber mat 210 contains metal ions (eg, gold ions) in the mat.

Next, a step of drying the fiber mat 210 is performed. The drying step can be carried out in ambient conditions, for example, can be dried at about 60 °C.

Subsequently, a step of forming a fiber mat in which the deionized water is absorbed by dropping deionized water on the fiber mat 210 is performed.

As described above, since the deionized water absorption rate of the PF-108 material contained in the fiber mat is very high, the deionized water can be sufficiently absorbed in the fiber mat, and the higher the content of PF-108, the higher the absorption rate of deionized water. have.

The step of removing excess deionized water can then be carried out.

Subsequently, a step of forming a metal nanoparticle pattern is performed by exposing the fiber mat 210 in which the deionized water is absorbed to plasma.

Only a portion of the fiber mat 210 may be exposed to plasma, and metal ions are reduced in the exposed portion to form a metal nanoparticle pattern.

For pattern formation, a pair of computer-controlled stepping motors can be used to move the substrate in the x and y directions.

As described above, due to the PF-108 included in the fiber mat, the deionized water absorption rate of the fiber mat can be greatly increased, and thus, the reduction reaction of metal ions is promoted in a later step, thereby The density of nanoparticles can be greatly increased, and the formed pattern can be made clearer and clearer.

The shape of the pattern can vary depending on the design. Depending on the design, a desired pattern can be formed by exposing only a portion of the fiber mat.

=25 mm, Cat.No:SL.HP020025D)는 SciLab, Korea.로부터 구매하였다. 깨끗한 선형의 삼블록(triblock) 중합체인 SBS(폴리스티렌 함량 28.4 wt%(Mn = 142,000 g/mol))는 Kraton, USA.로부터 구매하였다. PF-108(poly(ethylene glycol)(PEG) 함량 82.5 wt% (Mn = 14,600 g/mol))은 Sigma-Aldrich, Korea.로부터 구매하였다. 테트라하이드로퓨란(Tetrahydrofuran, THF, 99.5%) 및 N,N-dimethylformamide(DMF, 99%)은 J.T. Baker, USA.로부터 구매하였다.In the following, Gold(III) chloride trihydrate (HAuCl ₄ ㆍ3H ₂ O, 99.9% purity), potassium dicyanoaurate (KAuCN ₂ , 98% purity), and D-(-)-fructose are purchased from Sigma-Aldrich, Korea. I did. HCl (36.5 ~ 38%) and ethylalcohol anhydrous (C ₂ H ₅ OH, 99.9% purity) were purchased from Duksan Chemical and Daejeong Chemical. Pt foil (0.025 mm thick, 99.9% purity) applied to the anode was purchased from Alfa Aesar, USA. High purity helium gas (99.999% purity) was used to generate the AC-driven atmospheric pressure plasma. Deionized water (18.2 MΩ·cm) used in the experiment was treated through a Millipore water purification system (Millipore Corp., Billerica, MA, USA). Hydrophilic polytetrafluoroethylene (PTFE) filter (pore size 0.2 ㎛,

=25 mm, Cat.No:SL.HP020025D) was purchased from SciLab, Korea. A clean linear triblock polymer, SBS (polystyrene content 28.4 wt% (Mn = 142,000 g/mol)) was purchased from Kraton, USA. PF-108 (poly(ethylene glycol) (PEG) content 82.5 wt% (Mn = 14,600 g/mol)) was purchased from Sigma-Aldrich, Korea. Tetrahydrofuran (THF, 99.5%) and N,N-dimethylformamide (DMF, 99%) were purchased from JT Baker, USA.

In addition, hereinafter, the surface plasmon resonance band of gold (Au) nanoparticles was measured using a UV-VIS spectrometer (Shimadzu UV-3600, Shimadzu Corporation, Japan). Samples were extracted every 15 minutes when about 1 ml of the solution was diluted with about 3 ml of deionized water, and the spectrum was measured in the range of about 300 to 800 nm. RMS current and RMS voltage were measured with a high voltage probe (P6015A, Tektronix, USA) and an AC current probe (P6022, Tektronix, USA). Voltage was measured with a digital oscilloscope (DPO 2002B, Tektronix, USA). The contact angle was measured with a Drop shape analyzer (KRUSS, Germany). Approximately 20 μl drops of ethanol or deionized water were placed on an electrospinning mat and the contact angle was characterized as a function of time. Field emission scanning electron microscopy (FE-SEM, ZEISS, Germany) and optical microscopes (KH-7700, Hirox, Japan) were used to measure the surface morphology. High-resolution transmission electron microscopy (HR-TEM) was used with a Tecnai G2 F20 operating at about 200 kV.

= 1.6 mm)을 포함한다. 헬륨(He) 가스 플로우(flow)가 글래스 튜브에 연결되어 있고, 질량 유량 컨트롤러(mass flow controller, MFC)에 의해 조절된다. 교류-구동 대기압 플라즈마는 글래스 튜브의 팁-노즐(tip-nozzle)에서 형성되었다. 실험이 진행되는 동안, 고정된 약 500 sccm의 헬륨 가스 유속, 조절되는 약 3 ~ 4 kV의 인가 전압, 조절되는 약 10 ~ 25 kHz의 주파수(frequency)의 조건에서, 교류-구동 대기압 플라즈마가 작동되었다. 실험이 진행되는 동안, 듀티 사이클(duty cycle)은 약 50 %에서 고정되었다.In addition, hereinafter, plasma was generated by a single electrode (ATMD-02, Applied Plasma Devices, Korea) of AC hig-voltage power. The plasma generating unit is connected to high voltage AC, and an internal electrode (tungsten rod, which is disconnected from the external environment) using a narrow glass tube (inner diameter of about 1 mm)

= 1.6 mm). The helium (He) gas flow is connected to the glass tube and is regulated by a mass flow controller (MFC). An alternating current-driven atmospheric pressure plasma was formed in the tip-nozzle of the glass tube. During the experiment, an AC-driven atmospheric pressure plasma was operated under conditions of a fixed helium gas flow rate of about 500 sccm, a controlled applied voltage of about 3 to 4 kV, and a controlled frequency of about 10 to 25 kHz. Became. During the experiment, the duty cycle was fixed at about 50%.

In order to drive the plasma-induced reaction at the plasma-liquid interface, an AC-driven atmospheric pressure and a platinum (Pt) ground electrode were installed on the half-cell. AC-driven atmospheric pressure plasma and Pt electrode (1.25 mm Х 25 mm) were disposed in each reduction reactor and oxidation reactor, and the reduction reactor and the oxidation reactor were separated by a glass frit. Plasma-induced reactions were carried out for up to about 90 minutes.

Direct recording was performed using AC-driven atmospheric pressure plasma. The xy-stage was driven by a pair of computer-controlled stepping motors to move the substrate in the x and y directions. The step size for scanning was about 1 μm, and the scanning speed was fixed at about 100 μm/sec. To obtain a high-resolution pattern, a glass micropipette and tungsten wire (ф = 250 μm) of about 10 μm diameter (μTip™, WPI, USA) were used.

For the fabrication of the fiber mat, a nozzle to collector distance of about 15 cm, a fixed flow rate of about 15 μl/min, room temperature and approx. The electrospinning process using SBS and PF-108 was performed under a voltage condition of about 20 kV at 25% relative humidity. A clear solution was prepared by dissolving SBS (15 wt%) and PF-108 (various contents, eg 0, 2, 4, 6 wt%, etc.) in THF/DMF (3:1 mixing ratio). The fibers were collected for about 4 hours, and the fibers were separated in a collector. The average thickness of the fiber mat was about 0.86 mm.

FIG. 2 (a) is a photograph showing an example of the apparatus for manufacturing metal nanoparticles of FIG. 1, (b) is a TEM image of metal nanoparticles manufactured through a reduction reaction for about 90 minutes, and (c) is It is a graph showing the UV-Vis absorbance spectrum for confirming the formation of metal nanoparticles.

Referring to FIG. 2, in order to confirm a plasma-induced reduction reaction by an AC-driven atmospheric pressure plasma, a reaction in a half cell containing a gold precursor solution was observed. Each of the reduction reactor and the oxidation reactor was filled with about 50 ml of an electrolyte solution, and the electrolyte solution contained about 0.5 mM HAuCl ₄ , about 10 mM D-(-)-fructose, and about 1 mM HCl. The plasma was ignited on the surface of the electrolyte for about 90 minutes at an applied voltage of about 4 kV, a frequency of about 25 kHz. As a result, the color change from yellow to purple occurred only in the reduction reactor (plasma reactor), which is an indicator of the formation of gold nanoparticles. On the other hand, no color change was observed in the oxidation reaction tank (FIG. 2(a)).

To confirm the formation of gold nanoparticles, UV-VIS absorbance spectroscopy was performed (FIG. 2(c)). As a result, a plasmon band was clearly observed in the wavelength band of about 530 nm, indicating the presence of spherical gold nanoparticles.

Additionally, spherical particles with an average diameter of about 50 nm were observed in the HR-TEM photograph. In Fig. 2(d), a lattice structure having a lattice spacing of about 0.24 nm was observed, which corresponds to the structure of gold (Au) of a face-centered cubic structure (fcc).

These results indicate that the AC-driven atmospheric pressure plasma induced a reduction reaction of the gold precursor at the plasma-liquid interface, although the voltage applied to the electrode was an AC voltage oscillating between a positive value and a negative value.

3 are graphs showing UV-Vis absorbance spectra according to an input voltage, a frequency, and a grounding type. 4 is a graph showing a change in intensity of a peak at 530 nm in the UV-Vis absorption spectrum.

In relation to the plasma-liquid interaction by AC-driven atmospheric pressure plasma, the relationship between the RMS current and the rate of the reduction reaction was analyzed.

Referring to FIG. 3, the RMS current of the AC-driven atmospheric pressure plasma can be adjusted by adjusting the applied voltage, frequency, and electrical ground change. Additionally, we performed plasma-induced reduction reactions under various operating conditions, and measured UV-VIS absorbance as a function of time, and the results are shown in FIG. 3. When the applied voltage decreased from 4 kV to 3 kV, the RMS current decreased from 7.4 mA to 5.4 mA, and when the frequency of AC power decreased from 25 kHz to 10 kHz, the RMS current decreased from 7.4 mA to 4.1 mA. . Here, as the RMS current decreases, the peak intensity of UV-VIS absorbance significantly decreases. However, it can be seen that all of the peak positions are almost the same.

Meanwhile, the RMS current was found to be independent of the type of ground (electrical ground, floating ground), and the intensity of UV-VIS absorbance was also similar.

Referring to FIG. 4, as a whole, the intensity of UV-VIS absorbance increased linearly with the plasma exposure time. As the applied voltage and frequency decreased, the RMS current of the plasma decreased with the slope indicating the reduction rate. On the other hand, the RMS current did not change according to the grounding method. Here, the linear increase in UV-VIS absorbance at a given RMS current means a relatively constant reduction rate, and a constant electron flux from the AC-driven atmospheric pressure plasma to the liquid surface (electrons per unit time area) Number). Additionally, as the RMS current decreases, the electron density in the plasma decreases, so that a low flux of electrons reaches the solution surface, and the reduction rate decreases. Thus, in conclusion, the plasma-induced reduction reaction is proportional to the RMS current of the AC-driven atmospheric pressure plasma, and the electrochemical reaction occurs at the plasma-liquid (electrolyte) interface.

5 are graphs showing TEM images and particle size distribution of particles of metal nanoparticles according to plasma exposure time. (a) and (e) are when plasma exposure time is 30 minutes, (b) and (f) are 45 minutes, (c) and (g) are 60 minutes, and (d) and (h) are 90 minutes Indicates the time.

Referring to FIG. 5, no significant change in the maximum peak position was observed as a function of plasma exposure time. This indicates that the particle size of the metal nanoparticles hardly changed during the plasma-induced reduction reaction. The average particle size was found to be about 50 nm, showing a fairly wide distribution.

These results are in good agreement with the UV-VIS absorbance results. Thus, it means that the degree of reduction of the gold precursor becomes larger as the UV-VIS absorbance intensity increases. However, there is little change in the particle size of the nanoparticles during the plasma-induced reduction reaction.

7 are images showing a direct recording process using an AC-driven atmospheric pressure plasma according to an embodiment. The applied voltage for plasma generation was about 4 kV, the frequency was about 25 kHz, the duty cycle was about 50%, and the helium gas injection rate was about 100 sccm.

The fiber mat was _{immersed in an ethanol solution containing 200 mM HAuCl 4} for about 30 minutes, sequentially dried under ambient conditions, and then DI water was placed on the fiber mat. Excess deionized water was gently removed with Kimwipes, an industrial paper wiper, and a direct recording process using an AC-driven atmospheric pressure plasma was performed. A dark pink interdigitated pattern was clearly formed, indicating the formation of gold nanoparticles. In addition, the patterned fiber mat is flexible and highly stretchable.

8 shows SEM images of an electrospun fiber mat containing (a) 0, (b) 2, (c) 4 and (d) 6% of PF-108, respectively. 9 shows the AT-FTIR (FT/IR-6100, Jasco) spectrum result of the fiber mat of FIG. 8D.

It can be seen that the fiber density increases from (a) to (d) of FIG. 8, and in FIG. 9, peaks corresponding to styrene of SBS ^{appeared at 1492, 1451, and 911 cm -1} , corresponding to butadiene. A peak appeared at ^{963 cm -1.} In addition, a peak indicating COC coupling vibration derived from PF-108 appeared at ^{1100 cm -1.} Thus, the AT-FTIR spectrum indicates that PF-108 is present in the SBS.

10 is a graph showing the absorption rate of ethanol and water according to the content of PF-108 in the fiber mat.

After dropping about 20 [mu]l drop of ethanol or deionized water onto the fiber mat, the absorption rate of the fiber mat to ethanol and deionized water was measured. The fiber mat was dried at about 60° C., and the weight of the dried fiber mat was measured (W _dry ). Then, the dried fiber mat was immersed in deionized water or ethanol for about 5 minutes. Excess deionized water or ethanol was removed with kimwipes and weighed (W _wet ). For example, the water absorption rate was determined by the following equation.

Referring to FIG. 10, the water absorption rate gradually increased as the content of PF-108 increased from 0 to 4 wt%, and was saturated at about 150%. On the other hand, the ethanol absorption rate rapidly decreased at 2 wt%, and thereafter hardly changed. Therefore, it can be seen that the water and ethanol absorption rate can be controlled by adjusting the amount of SBS and PF-108 in the fiber mat including SBS and PF-108.

11 are photographs showing a direct recording process using an AC-driven atmospheric pressure plasma on a fiber mat according to an embodiment. Fig. 11(a) shows when the fiber mat contains deionized water, and (b) shows when the deionized water is not included.

Referring to FIG. 11, when recording was performed directly on the dried fiber mat without deionized water, no pattern was formed. These results indicate that in a direct recording process using an AC-driven atmospheric pressure plasma, deionized water plays a key role in the formation of gold nanoparticles.

12 are photographs showing a change in contact angle with time for about 20 μl of deionized water of a fiber mat according to an embodiment. Figure 12 (a) is a case where about 15 wt% of SBS is included in the fiber mat and PF-108 is not included, and (b) is about 15 wt% of SBS and about 2 wt% of PF-108 are included. (C) is about 15 wt% of SBS and about 4 wt% of PF-108, (d) is about 15 wt% of SBS and about 6 wt% of PF-108 This is the case.

13 are photographs showing a change in contact angle with time for about 20 μl of ethanol of a fiber mat according to an embodiment. Figure 13 (a) is a case where about 15 wt% of SBS is included in the fiber mat and PF-108 is not included, and (b) is about 15 wt% of SBS and about 2 wt% of PF-108 are included. (C) is about 15 wt% of SBS and about 4 wt% of PF-108, (d) is about 15 wt% of SBS and about 6 wt% of PF-108 This is the case.

Referring to FIGS. 12 and 13, the fiber mat exhibited rapid absorption of deionized water as the content of PF-108 increased. Therefore, when the content of PF-108 in the fiber mat is increased, the water absorption rate of the fiber mat is increased, so that the water absorption rate can be adjusted.

In comparison, in the case of ethanol, the fiber mat immediately absorbed ethanol regardless of the content of PF-108.

Figure 14 (a) is a diagram showing a direct recording process using an AC-driven atmospheric pressure plasma, and (b) to (d) are direct recording when the fiber mat contains SBS and does not contain PF-108. High-resolution optical photos and SEM photos of the fiber mat, (e) to (g) are high-resolution optical photos and SEM photos of the fiber mat directly recorded when the fiber mat contains SBS and about 2 wt% of PF-108 Represents. The applied voltage for plasma generation is about 3 kV, the frequency is about 25 kHz, the duty cycle is about 50%, the helium gas injection rate is about 10 sccm, and the scanning rate of direct recording is about 10 μm. It is about 100 μm/sec in tip size. The fiber mats were _{immersed in an ethanol solution containing dir 100 mM HAuCl 4} for about 10 minutes and placed on a hydrophilic PTFE (Polytetrafluoroethylene) filter serving as a reservoir for deionized water. After performing the direct recording process by AC-driven atmospheric pressure plasma, the fiber mats were washed with ethanol to remove unreacted gold precursors.

14, clear patterns were observed in both fiber mats. However, as a result of reading the high-resolution optical image, the fiber mat made of only SBS showed a relatively low gold nanoparticle density and a higher gold precursor density. On the other hand, the fiber mat containing SBS and 2 wt% of PF-108 showed a relatively higher gold nanoparticle density. From this, it can be seen that PF-108 performs a key function of promoting the containment of deionized water, and a hydrophilic PTFE filter prevents evaporation of moisture, thereby promoting a reduction reaction of gold ions.

In addition to the hydrophilic filter, a reduction reaction of gold ions can be promoted by minimizing evaporation of deionized water by applying materials such as paper.

(A) of FIG. 15 is a diagram showing a direct recording process using an AC-driven atmospheric pressure plasma according to an embodiment, (b) is a high-resolution optical picture of a fiber mat in which the direct recording is made, and (c) is an SEM picture. In Figure 15 (b), (i) is a case where about 15 wt% of SBS is included in the fiber mat, and PF-108 is not included, and (ii) is about 15 wt% of SBS and PF-108 is about 2 wt% is included, (iii) is when about 15 wt% of SBS is included and about 4 wt% of PF-108 is included, and (iv) is about 15 wt% of SBS and PF-108 is about This is the case where 6 wt% is included. Fiber mats were _{immersed in a solution of deionized water containing 100 mM KAuCN 2} for about 10 minutes, and excess deionized water was removed with Kimwipes.

Referring to FIG. 15, as a result of direct recording using an AC-driven atmospheric pressure plasma, it was found that the pattern became more distinct as the content of PF-108 increased from 0 to 6 wt%. In addition, looking at the corresponding SEM image, it can be seen that the content of gold nanoparticles increases as the content of PF-108 increases from 0 to 6 wt%. The fiber mat was not destroyed even after direct recording. From these results, we can see that the deionized water absorbed by the fiber mat plays a key role in the reduction reaction. Deionized water can promote the mobility of metal ions in the polymer film. In addition, it can be seen that the driving force of the plasma-induced reaction in the polymer film is absorbed deionized water, and the electrochemical reaction occurs at the interface of the plasma-polymer film.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It belongs to the scope of rights of

100: metal nanoparticle manufacturing apparatus 110: reduction reactor
114: electrolyte 118: plasma generation unit
130: oxidation reactor

Claims (14)

In an apparatus for manufacturing metal nanoparticles including a reduction reaction tank including an electrolyte solution containing metal ions and a plasma generation unit, and an oxidation reaction tank including an oxidation electrode, an AC-driven atmospheric pressure plasma ( Generating AC-driven atmospheric pressure plasma), and
Forming metal nanoparticles by reducing the metal ions and electrons supplied from the AC-driven atmospheric pressure plasma
Including,
As the root mean square (RMS) current of the AC-driven atmospheric pressure plasma increases, the reaction kinetics of the reduction reaction increases.
Method for producing metal nanoparticles.
In claim 1,
As the voltage applied to the plasma generating unit increases, the RMS current of the AC-driven atmospheric pressure plasma increases.
In claim 1,
A method of manufacturing metal nanoparticles in which the RMS current of the AC-driven atmospheric pressure plasma increases as the frequency of the AC power applied to the plasma generating unit increases.
In claim 1,
The metal is a method of manufacturing a metal nanoparticle containing gold (Au).
A fibrous mat including SBS (poly(styrene-block-butadiene-block-styrene)) and PF-108 (poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)) ) To prepare,
Immersing the fiber mat in a metal precursor solution containing metal ions,
Drying the fiber mat,
Dropping deionized water on the fiber mat to form a fiber mat in which deionized water is absorbed, and
The fiber mat in which the deionized water is absorbed is exposed to an AC-driven atmospheric pressure plasma generated by applying an AC voltage to a plasma generating unit to reduce the metal ions to form a metal nanoparticle pattern ( forming a pattern)
Including
Method of recording metal nanoparticles.
In clause 5,
A method of recording metal nanoparticles in which the content of the PF-108 is 0.1 to 30% by weight, based on the total mass of the fiber mat.
In paragraph 6,
A method of recording metal nanoparticles in which the deionized water absorption rate of the fiber mat in which the deionized water is absorbed increases as the content of PF-108 increases.
In clause 7,
A method of recording metal nanoparticles in which the density of the metal nanoparticles generated in the step of forming the metal nanoparticle pattern increases as the content of the PF-108 increases.
In clause 5,
In the step of preparing the fiber mat,
A method of recording metal nanoparticles in which the fiber mat is formed by electrospinning a solution containing the SBS, the PF-108, DMF (dimethylformamide), and THF (N,N-dimethylformamide).
In clause 5,
The method of recording metal nanoparticles, wherein the metal includes gold (Au), and the metal precursor solution is an alcohol solution containing gold ions.
In clause 5,
The method of recording metal nanoparticles further comprising removing excess deionized water between the step of forming the fiber mat in which the deionized water is absorbed and the step of forming the metal nanoparticle pattern.
In clause 5,
In the step of forming the metal nanoparticle pattern,
A method of recording metal nanoparticles in which the pattern is formed by exposing a portion of the fiber mat in which the deionized water is absorbed to the AC-driven atmospheric pressure plasma.
In clause 5,
In the step of forming a fiber mat in which deionized water is absorbed,
A method of recording metal nanoparticles in which a filter or paper for preventing evaporation of the deionized water is disposed on the fiber mat.
In claim 13,
The filter is a hydrophilic polytetrafluoroethylene (PTFE) filter, a method for recording metal nanoparticles.

Images