ELECTRODE, METHOD FOR PREPARING SAME, AND ELECTROSTATIC DISCHARGE SYSTEM COMPRISING SAME

Abstract

The present application relates to an electrode, a method for preparing the electrode, and an electrostatic discharge system comprising the electrode. According to the electrode, the method for preparing the electrode, and the electrostatic discharge system comprising the electrode of the present application, the electrostatic discharge system exhibits an excellent anion generation concentration, maintains a residual ozone concentration of an indoor threshold or lower, prevents the corrosion of the electrode, and may exhibit excellent antimicrobial performance.

Claims

1. An electrode comprising: a body; a protrusion which has a nano size and is formed on a surface of the body; and a coating portion formed by applying conductive carbon on surfaces of the body and of the protrusion.

2. The electrode of claim 1, wherein a residual rate of bacteria, which is measured by supplying air to the electrode at a flow rate of 5 L/min, applying a DC negative voltage of 7 kV to generate anions, and injecting air including the generated anions into a 22 L chamber with 2,000 bacteria/cm3 of the bacteria to expose the bacteria to the anions, is 25% or less.

3. The electrode of claim 1, wherein a residual number of bacteria, which is measured by supplying air to the electrode at a flow rate of 5 L/min, applying a DC negative voltage of 7 kV to generate anions, and injecting air including the generated anions into a 22 L chamber with 2,000 bacteria/cm.sup.3 of the bacteria to expose the bacteria to the anions, is a 12 colony-forming unit (CFU) or less.

4. The electrode of claim 1, wherein an anion generation concentration, which is measured by supplying air to the electrode at a flow rate of 5 L/min and applying a DC negative voltage of 7 kV, is 8?10.sup.5 ions/cm.sup.3 or more.

5. (canceled)

6. The electrode of claim 4, wherein a residual ozone concentration when anions are generated is less than 50 ppb.

7. The electrode of any one of claims 2, wherein an electric field applied when anions are generated is in a range of 500 V/m to 500,000 V/m.

8. The electrode of claim 1, wherein the body has a pin shape.

8. The electrode of claim 1, wherein the body has a pin shape.

9. The electrode of claim 1, wherein the body includes a transition metal including iron, tungsten, silver, copper, gold, nickel, cobalt, zinc, molybdenum, or an alloy thereof.

10. The electrode of claim 1, wherein the protrusion has a radius of curvature of 1 nm to 10 ?m.

11. The electrode of claim 1, wherein the protrusion includes a transition metal including iron, tungsten, silver, copper, gold, nickel, cobalt, zinc, molybdenum, or an alloy thereof.

12. The electrode of claim 11, wherein the conductive carbon is included at a content of 10 to 40 parts by weight with respect to 100 parts by weight of the transition metal.

13. A method of manufacturing the electrode of claim 1, the method comprising: a forming operation of forming a protrusion having a nano size on a surface of a body; and a coating operation of applying conductive carbon on surfaces of the body and the protrusion to form a coating portion.

14. The method of claim 13, wherein the forming operation is performed through etching or attaching.

15. The method of claim 14, wherein the etching is performed through at least one selected from wet etching, optical etching, and physical etching.

16. The method of claim 15, wherein the wet etching is performed by immersing the body in an etching solution and then applying ultrasonic waves.

17. The method of claim 16, wherein an application time of the ultrasonic waves is in a range of 10 seconds to 1 hour.

18. The method of claim 14, wherein the attaching is performed by attaching catalyst particles to the surface of the body.

19. The method of claim 18, wherein the catalyst particles include a transition metal including iron, tungsten, silver, copper, gold, nickel, cobalt, zinc, molybdenum, or an alloy thereof.

20. The method of claim 13, wherein the coating operation is performed through one method selected from a chemical vapor deposition method, a sputtering method, an atomic layer deposition method, a spray coating method, and a spin coating method.

21. (canceled)

22. An electrostatic discharge system comprising the electrode of claim 1.

Description

DESCRIPTION OF DRAWINGS

[0050] FIG. 1 is a diagram illustrating a high efficiency particulate air (HEPA) filter included in a conventional electrostatic system.

[0051] FIG. 2 is a diagram illustrating an ultraviolet (UV) sterilizer included in the conventional electrostatic system.

[0052] FIG. 3 is a diagram exemplarily illustrating an electrode according to one embodiment of the present application.

[0053] FIGS. 4 to 9 are diagrams exemplarily illustrating an electrode manufactured using a laser lithography process according to another embodiment.

[0054] FIGS. 10 to 15 are diagrams exemplarily illustrating an electrode manufactured using a laser lithography process according to another embodiment.

[0055] FIG. 16 is a diagram illustrating an exemplary apparatus for manufacturing an electrode according to one embodiment of the present application.

[0056] FIG. 17 shows a low magnification image (left, ?500) and a high magnification image (right, ?10000) captured by photographing an electrode manufactured in Example 1 using a scanning electron microscope.

[0057] FIG. 18 shows a low magnification image (left, ?500) and a high magnification image (right, ?10000) captured by photographing an electrode manufactured in Example 3 using a scanning electron microscope.

[0058] FIG. 19 shows a low magnification image (left, ?500), a high magnification image (middle, ?10000), and an ultra-high magnification image (right, ?50000) captured by photographing an electrode manufactured in Example 5 using a scanning electron microscope.

[0059] FIG. 20 shows a low magnification image (left, ?500) and a high magnification image (right, ?10000) captured by photographing an electrode manufactured in Comparative Example 1 using a scanning electron microscope.

[0060] FIG. 21 shows energy dispersive X-ray spectroscopy elemental map images (top) and a graph (bottom) for the electrode manufactured in Example 1.

[0061] FIG. 22 shows energy dispersive X-ray spectroscopy elemental map images for the electrode manufactured in Comparative Example 1.

[0062] FIG. 23 is a diagram exemplarily illustrating an anion concentration evaluation apparatus for measuring an anion generation concentration of electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1.

[0063] FIG. 24 is a graph showing an anion concentration of the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1.

[0064] FIG. 25 is a diagram exemplarily illustrating an antibiosis evaluation apparatus for evaluating the residual number of cells and antibacterial efficiency according to relative electric field strength of the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1.

[0065] FIG. 26 is a graph showing the residual number of cells according to relative electric field strength of the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1.

[0066] FIG. 27 is a graph showing the antibacterial efficiency of cells according to relative electric field strength of the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1.

[0067] FIG. 28 is a graph showing an ionization radius onset voltage according to a radius of curvature of a protrusion of the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1.

[0068] FIG. 29 shows low magnification images (?500) captured by photographing the protrusion of the electrode manufactured in Example 1 using a scanning electron microscope.

[0069] FIG. 30 is a diagram exemplarily illustrating a residual ozone concentration evaluation apparatus for measuring a residual ozone concentration according to the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1.

BEST MODE OF THE INVENTION

[0070] Hereinafter, the above contents will be described in more detail with reference to Examples and Comparative Example. However, the scope of the present application is not limited to the contents disclosed below.

Example 1: Manufacturing of Electrode

[0071] FIG. 16 is a diagram illustrating an exemplary apparatus for manufacturing an electrode according to one embodiment of the present application. An electrode was manufactured using the apparatus shown in FIG. 16. Specifically, an electrode 21 with a nano-pin shape including tungsten (tungsten pin manufactured by American Elements) was immersed into a beaker 22 containing an etching solution (667498 manufactured by Sigma-Aldrich), and then the beaker 22 was immersed in an ultrasonic bath 23 filled with water to generate ultrasonic waves for 1 minute, thereby forming protrusions on a surface of a body.

[0072] Thereafter, an electrode in which the protrusions were formed on the surface of the body having a nano-pin shape was put into a chemical vapor deposition chamber 24, 100 mL/min of nitrogen (N.sub.2) was injected into the vapor deposition chamber 24 under conditions of 2 Torr and 20? C./min for 20 minutes, a temperature of the chemical vapor deposition chamber 24 was raised to 650? C. for 70 minutes, acetylene (C.sub.2H.sub.2) was injected into the vapor deposition chamber 24 at a rate of 30 mL/min for 10 minutes to cause a reaction for 50 minutes, and then the vapor deposition chamber 24 was naturally cooled to manufacture an electrode in which carbon was applied on surfaces of the body and the protrusions. In this case, a pressure in the vapor deposition chamber 24 may be controlled by a vacuum pump 25, and a radius of curvature of the protrusion may be 2 ?m or less. In addition, low magnification images (?500) were captured by photographing the protrusions of the electrode manufactured in Example 1 using a scanning electron microscope (SEM, S-4800 manufactured by Hitachi, Ltd., Japan). Results thereof are shown in FIG. 29.

Example 2: Manufacturing of Electrode

[0073] An electrode was manufactured in the same manner as in Example 1, except that an electrode with a nano-pin shape including tungsten was immersed in a beaker containing an etching solution, and then ultrasonic waves were generated for 2 minutes to form protrusions on a surface of a body. In this case, a radius of curvature of the protrusion may be 1 ?m or less.

Example 3: Manufacturing of Electrode

[0074] An electrode was manufactured in the same manner as in Example 1, except that an electrode with a nano-pin shape including tungsten was immersed in a beaker containing an etching solution, and then ultrasonic waves were generated for 3 minutes to form protrusions on a surface of a body. In this case, a radius of curvature of the protrusion may be 500 nm or less.

Example 4: Manufacturing of Electrode

[0075] An electrode was manufactured in the same manner as in Example 1, except that an electrode with a nano-pin shape including tungsten was immersed in a beaker containing an etching solution, and then ultrasonic waves were generated for 4 minutes to form protrusions on a surface of a body. In this case, a radius of curvature of the protrusion may be 300 nm or less.

Example 5: Manufacturing of Electrode

[0076] An electrode was manufactured in the same manner as in Example 1, except that an electrode with a nano-pin shape including tungsten was immersed in a beaker containing an etching solution, and then ultrasonic waves were generated for 5 minutes to form protrusions on a surface of a body. In this case, a radius of curvature of the protrusion may be 100 nm or less.

Comparative Example 1: Manufacturing of Electrode

[0077] An electrode with a nano-pin shape including tungsten of Example 1, in which a protrusion and a coating portion were not formed, was manufactured. In this case, the electrode manufactured in Comparative Example 1 does not include the protrusion, and a radius of curvature of a sharp portion at an upper end portion of a body may be 100 ?m.

Experimental Example 1: Evaluation of Electrode Surface Shape and Composition

[0078] Surface shapes of the electrodes manufactured in Examples 1, 3, and 5 and the electrode manufactured in Comparative Example 1 were photographed using a SEM (S-4800 manufactured by Hitachi, Ltd., Japan) to capture low and high magnification images. Results thereof are shown in FIGS. 17 to 20.

[0079] In addition, compositions of the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1 were observed using energy dispersive X-ray spectroscopy (EDX, S-4800 manufactured by Hitachi, Ltd., Japan). Results thereof are shown in FIGS. 21 and 22 and Table 1 below. In this case, since carbon tape is used to fix the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1, a content of carbon is a content including a content of the carbon tape. In addition, contents of oxygen and potassium are contents due to an etching process.

TABLE-US-00001 TABLE 1 Example 1 Comparative Example 1 W 68.18 wt % 100 wt % C 18.85 wt % 0 wt % O 12.82 wt % 0 wt % Fe 0 wt % 0 wt % K 0.20 wt % 0 wt %

[0080] As shown in FIGS. 17 to 22 and Table 1, it was confirmed that, unlike the electrode manufactured in Comparative Example 1, the electrodes manufactured in Examples 1, 3, and 5 had a nano-pin-shaped body, and at the same time, a carbon component was included in the protrusions.

Experimental Example 2: Evaluation of Anion Generation Concentration of Electrode

[0081] An anion generation concentration of the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1 was evaluated using the anion concentration evaluation apparatus of FIG. 23. Specifically, as shown in FIG. 23, an electrode 31 manufactured in each of Examples 1 to 5 and Comparative Example 1 was positioned on an anion generating unit 33, a flow rate adjusting unit 33 was used to supply air at a flow rate of 5 L/min from an air supply unit 32 to the anion generating unit 34, and a DC negative voltage of 7 kV was applied to each of the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1 to generate anions. Afterwards, an anion measuring unit 35, which was installed at a distance of 3.5 cm from the anion generating unit 34 and uses an air ion meter (NKMH-103 manufactured by Meiko Sangyo Co., Ltd., Japan), was used to measure a concentration of anions generated in the anion generating unit 34. Results thereof are shown in FIG. 24. In this case, applied electric field strength may be 200,000 V/m.

[0082] As shown in FIG. 24, it was confirmed that a concentration of anions generated in the electrodes manufactured in Examples 1 to 5 was higher than a concentration of anions generated in the electrode manufactured in Comparative Example 1. In particular, the concentration of anions generated in the electrode manufactured in Example 4 was 32?10.sup.5 ions/cm.sup.3 which was confirmed to be 6 times or more higher than the concentration of anions generated in the electrode manufactured in Comparative Example 1.

Experimental Example 3: Evaluation of Antibiosis of Electrode

[0083] The antibiosis evaluation apparatus of FIG. 25 was used to evaluate the residual number of cells and antibacterial efficiency according to relative electric field strength of the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1. Results thereof are shown in FIGS. 26 and 27, respectively. Specifically, as shown in FIG. 25, an electrode 41 manufactured in each of Examples 1 to 5 and Comparative Example 1 was positioned on an anion generating unit 44, a flow rate adjusting unit 43 was used to supply air at a flow rate of 5 L/min from an air supply unit 42 to the anion generating unit 44, and a DC negative voltage of 7 kV was applied to each of the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1 to generate anions. Thereafter, air containing anions is injected into a 22 L chamber 45 together with 2,000 bacteria/cm.sup.3 of Staphylococcus aureus to expose the Staphylococcus aureus to the anions, and then the Staphylococcus aureus was collected through a button sampler 46 (manufactured by SKC, Inc., USA). Thereafter, the Staphylococcus aureus collected in the button sampler 46 is dispersed in a buffer solution 47 and then smeared and cultured in a medium 48 to count the residual number of bacteria (CUF) according to the presence or absence of anions, thereby calculating antibacterial efficiency to calculate a residual rate of the Staphylococcus aureus.

[0084] As shown in FIG. 26, it was confirmed that, when an electric field was applied to the electrode manufactured in Example 1 and the electrode manufactured in Comparative Example 1, and thus anions were present, the residual number of the bacteria was smaller as compared with a case in which an electric field was not applied to the electrode manufactured in Comparative Example 1, and thus anions were not present. In addition, as shown in FIG. 27, it was confirmed that, as compared with a case in which an electric field is applied to the electrode manufactured in Comparative Example 1, the antibacterial efficiency was higher when anions were present by the electrode manufactured in Example 1, in which electric field strength was reduced to a level of ?. That is, it was confirmed that, when an electric field was applied to the electrode manufactured in Example 1, and thus anions were present, the residual rate of the bacteria was lower than when an electric field was not applied to the electrode manufactured in Comparative Example 1, and thus anions were not present.

Experimental Example 4: Evaluation of Ionization Discharge Onset Voltage According to Radius of Curvature of Protrusion

[0085] An ionization radius onset voltage according to a radius of curvature of a protrusion of each of the electrodes manufactured in Examples 1 to 5 and a radius of curvature of an upper end portion of a body of the electrode manufactured in Comparative Example 1 were calculated using General Formula 1 below. Results thereof are shown in FIG. 28. Since the electrode manufactured in Comparative Example 1 did not include the protrusion, a radius of curvature of a sharp portion at the upper end portion of the body was used.

[00002]$\begin{array}{cc}{V}_s=\frac{r}{2}?E?\ln \left[\frac{r+2d}{r}\right]& \left[\mathrm{General}\mathrm{Formula}1\right]\end{array}$

[0086] In General Formula 1, r is a radius of curvature of the protrusion, E is electric field strength when ionization begins to appear on surfaces of the body and the protrusions to generate anions, and d is a distance between the electrode and a ground plate.

[0087] As shown in FIG. 28, it was confirmed that, as the radius of curvature of the protrusion was decreased, the ionization discharge onset voltage for generating anions was lowered. As a result, it was confirmed that as the radius of curvature of the protrusion included in the electrode was decreased, electric field strength was lowered to suppress ozone generation.

Experimental Example 5: Evaluation of Residual Ozone Concentration According to Anion Generation of Electrode

[0088] A residual ozone concentration of the electrodes manufactured in Examples 1 to 5 and the electrode manufactured in Comparative Example 1 were evaluated using the residual ozone concentration evaluation apparatus of FIG. 30. Specifically, as shown in FIG. 30, the residual ozone concentration evaluation apparatus was designed in the same way as the anion concentration evaluation apparatus, except that, instead of the anion measuring unit 35 of the anion concentration evaluation apparatus shown in FIG. 23, an ozone measuring unit 55 including a sampling probe of a suction-type ozone monitor was installed to be connected to an anion generating unit 54. The residual ozone concentration was measured by measuring ozone present in a portion of the air in the anion generating unit 34.

[0089] As a result, it was confirmed that the residual ozone concentration in the electrodes manufactured in Examples 1 to 5 was lower than the residual ozone concentration in the electrode manufactured in Comparative Example 1. In particular, it was confirmed that the residual ozone concentration in the electrode manufactured in Example 1, to which an electric field was applied at electric field strength of ? of that of an electric field applied to the electrode manufactured in Comparative Example 1, was 50 ppb, which was considerably lower than the residual ozone concentration of 130 ppb in the electrode manufactured in Comparative Example 1, to which an electric field was applied at the above-described strength.

DESCRIPTION OF REFERENCE NUMERALS

[0090] 11: body

[0091] 12: protrusion

[0092] 13: coating portion

[0093] 21, 31, 41, 51: electrode

[0094] 22: beaker

[0095] 23: ultrasonic tank

[0096] 24: chemical vapor deposition chamber

[0097] 25: vacuum pump

[0098] 32, 42, 52: air supply unit

[0099] 33, 43, 53: flow rate control unit

[0100] 34, 44, 54: anion generating unit

[0101] 35: anion measuring unit

[0102] 45: chamber

[0103] 46: button sampler

[0104] 47: buffer solution

[0105] 48: medium

[0106] 55: ozone measuring unit