KR20220030466A - Method for enhancement of antibacterial activity of Ag nanomaterials and Ag nano article using the same - Google Patents

Abstract

The present invention relates to a method for improving the antibacterial activity of a silver nanomaterial, and a silver nanomaterial using the same. More specifically, the present invention relates to a method for improving the antibacterial activity of a silver nanomaterial capable of dramatically improving the antibacterial activity of a silver nanomaterial while maintaining transparency thereof, and a silver nanomaterial using the same. The method for improving the antibacterial activity of a silver nanomaterial according to the present invention comprises the steps of: i) providing a base substrate; ii) coating s silver nanomaterial on the base substrate; and iii) performing a heat treating at 220℃ or higher.

Description

Method for enhancement of antibacterial activity of Ag nanomaterials and Ag nano article using the same

The present invention relates to a method for improving the antibacterial activity of silver nanomaterials and to a silver nanomaterial using the same, and more particularly, to a method for improving the antibacterial activity of silver nanomaterials that can dramatically improve the antibacterial activity of silver nanomaterials while maintaining transparency, and silver using the same It is about nano products.

Recently, public interest in environmental and health issues has been increasing. In relation to the above issue, bacterial infection and the resulting disease and death are known to be a significant risk to public health worldwide. Therefore, antiseptics such as antibacterial agents and antibiotics have been developed. As an antibacterial agent, silver nanomaterials (AgNMs) have effective antibacterial activity against Gram-positive bacteria and Gram-negative bacteria, but have low toxicity to human cells at low concentrations. Therefore, silver nanomaterials have a potentially wide range of applications in the medical, scientific, food, and pharmaceutical industries. Nanomaterials are generally defined in at least one aspect as materials that are 1-100 nm in size. So far, many manufacturing methods have been developed for various types of silver nanomaterials. Various forms of the silver nanomaterial include, for example, nanowires, nanocubes, nanocoils, narorods, and nanoparticles. These AgNMs exhibit a much broader spectrum of antimicrobial activity compared to bulk silver.

Among AgNMs, silver nanowire (AgNW) is a unique structure, having a very long structure in a certain direction with a diameter of 10-200 nm, a length of 5-10 μm, and an aspect ratio of greater than 10. As an antimicrobial agent, silver nanowires have unique structural advantages, and their anti-overlapping properties when in film form allow researchers to maximize their large surface area and thus surface-dependent antimicrobial activity.

The AgNW film in the form of a mesh can be prepared by a wide variety of methods such as spin coating, drop casting, dip coating, spray coating, rod-coating, vacuum filtration, and slot-die coating. This mesh-shaped film structure is a transparent (ie optically advantageous) film. In the electrode field, AgNW is most often used as a source of a transparent electrode film. Furthermore, in terms of orientation, AgNWs mainly composed of {100} planes on the side surface showed strong antibacterial activity compared to Ag spherical nanoparticles mainly composed of {111} planes. This is because the {100} plane, which has high energy and high reactivity, has a larger contact surface than the {111} plane and quickly attaches to the bacterial film. Therefore, AgNWs are Escherichia coli ( E coli ), Staphylococcus aureus ( S aureus ), and some antibiotic-resistant bacteria (ie, Methicillin -resistant Staphylococcus aureus and Pseudomonas ) aeruginosa ) showed strong antibacterial activity against at least 12 species including .

However, experimentally, AgNW also exhibited lower antibacterial activity than AgNMS in the form of nanospheres, nanocubes, and nanoplates. This low antibacterial activity of AgNW is due to the slow release of positively charged ions (Ag ⁺ ) with a low surface area. It is widely known that Ag ⁺ release is the main key to the antibacterial action of AgNWs.

However, in the case of AgNW, there was no reason to use it by heat treatment because the properties as a nanowire were deteriorated during high-temperature heat treatment.

Patent Document 1: Japanese Patent Application Laid-Open No. 2008-013798 (Method for Manufacturing Nanowire-Type Metal Material and Composition Containing Nanowire-Type Metal Material)

It is an object of the present invention to provide a method for improving the antimicrobial activity of silver nanomaterials.

Another object of the present invention is to provide a silver nano product manufactured by using the method for improving the antimicrobial activity of the silver nano material.

The object of the present invention is not limited to the objects mentioned above, and other objects not mentioned will be clearly understood from the description of the detailed description.

According to one aspect, there is provided a method comprising: i) providing a base substrate; ii) coating the silver nanomaterial on the base substrate; and iii) heat-treating at 220° C. or higher.

According to an embodiment, in step i), the base substrate may be a transparent substrate.

According to an embodiment, in step ii), the silver nanomaterial may be one or more of nanowires, nanoprotrusions, nanopillars, nanodimples, nanocubes, nanocoils, and nanoembossing.

According to one embodiment, it may be heat-treated at 230 to 300 ℃ in step iii).

According to another aspect, there is provided a silver nanomaterial comprising 15% or more of Ag ₂ O, and at least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates.

According to an embodiment, the silver nanomaterial may be one or more of nanowires, nanoprotrusions, nanopillars, nanodimples, nanocubes, nanocoils, and nanoembossing.

According to an embodiment, the silver nanomaterial may be in the form of a film.

According to an embodiment, at least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates may be formed by heat treatment at 220° C. or higher.

According to an embodiment, the antibacterial activity of the silver nanomaterial may be improved by 25% or more compared to the silver nanomaterial before the heat treatment by the heat treatment.

According to one embodiment, the base substrate; and silver nanomaterials described herein; including, silver nano-products are provided.

According to an embodiment, the base substrate may be transparent.

According to an embodiment, the silver nano-product may be a transparent electrode.

According to an embodiment, the antimicrobial activity of the silver nanomaterial may be remarkably improved by heat treatment.

In particular, by treating silver nanomaterials in a top-down method, the problem of aggregation by the conventional bottom-up method and the problem that the specific surface area is reduced thereby can be improved, thereby remarkably improving the antimicrobial activity.

According to one embodiment, a silver nanomaterial with remarkably improved antibacterial activity can be efficiently manufactured by a simple process.

According to one embodiment, it is possible to efficiently manufacture a silver nano-product with remarkably improved antibacterial activity while minimizing a decrease in transmittance.

1 is (a) a silver nanowire film (AgNW), (b) a silver nanowire film heat-treated at 230 °C (AgNW-230 °C), and (c) a silver nanowire film heat-treated at 280 °C (AgNW-230) ℃) is an FE-SEM planar image.
2 is a view showing (a) Ag 3d core-level XPS high-resolution spectrum, (b) transmittance and light, and (c) haze and total light transmittance of AgNW, AgNW-230 °C, and AgNW-280 °C.
3 shows S. aureus of AgNW, AgNW-230 °C, and AgNW-280 °C silver nanowires. and antibacterial activity against E. coli . (a) is a planar photograph of the cultured agar-plate and antibacterial activity, (b) is S. aureus And (c) is a graph showing the reduction rate of E. coli . Bacterial experiments were performed by contacting the samples with an inoculum containing 4×10 ⁶ CFU of the experimental bacterial strain for 30 minutes.
Figure 4 is a schematic diagram of the antibacterial mechanism of AgNW, AgNW-230 ℃, and AgNW-280 ℃.

Objects, specific advantages and novel features of the present disclosure will become more apparent from the following detailed description and embodiments taken in conjunction with the accompanying drawings.

Prior to this, the terms or words used in the present specification and claims should not be construed in a dictionary meaning, and the inventor may properly define the concept of a term to describe his invention in the best way. Based on the principle that there is, it should be interpreted as a meaning or concept consistent with the technical idea of the present disclosure.

In this specification, when an element, such as a layer, portion, or substrate, is described as being "on," "connected to," or "coupled with" another element, it is directly "on", "on" the other element. It may be "connected" or "coupled", and one or more other elements may be interposed between both elements. In contrast, when an element is described as being "directly on," "directly connected to," or "directly coupled to," another element, no other element may be interposed between the two elements. .

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present disclosure. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In this specification, terms such as 'comprise' or 'have' are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, and one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

In the present specification, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated. In addition, throughout the specification, "on" means to be located above or below the target part, and does not necessarily mean to be located above the direction of gravity based on the direction of gravity.

Since the present disclosure can apply various transformations and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present disclosure to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present disclosure. In describing the present disclosure, if it is determined that a detailed description of a related known technology may obscure the gist of the present disclosure, the detailed description thereof will be omitted.

To improve the antibacterial activity of AgNWs, micronization treatment may be a desirable strategy. Because of Rayleigh-Plateau instability, at high temperatures above 200 °C, AgNW structure collapses into separate short wires and droplets. This decay phenomenon was studied as structural breakdown by Joule heating of AgNW electrodes. As the applied temperature of the AgNW is increased by Joule heating or heat-treatment, the AgNW decays into smaller wires and particles. Therefore, the present inventors considered AgNW as an antibacterial material as a top-down synthesis method of AgNW with reduced size.

Herein, heat treatment was investigated as a potential technique to improve the functionality of AgNW antibacterial films. AgNW films prepared by spin-coating were heated to various temperatures. As a function of heat-treatment temperature, shape, chemical state, optical properties, and sheet resistance were determined by field emission scanning electron microscopy (FE-SEM), ultraviolet-infrared spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS). , and four-probes were used. In addition, antibacterial experiments against E. coli were performed. By comparative analysis, it was confirmed that the heat treatment temperature had a significant effect on the antibacterial activity of the AgNW film with respect to the investigated properties, and the present invention was completed.

Accordingly, according to one aspect of the present application, i) providing a base substrate; ii) coating the silver nanomaterial on the base substrate; and iii) heat-treating at 220° C. or higher.

Step i) is a step of providing a base substrate on which the silver nanomaterial is to be coated. Although not limited thereto, the base substrate may be a transparent substrate. The transparent substrate may be glass or plastic. When the base substrate is a transparent substrate, antibacterial activity can be imparted to the article without affecting the appearance of the article when applied to the article.

Step ii) is a step of coating the silver nanomaterial on the base substrate. The method for coating the silver nanomaterial is not particularly limited, and known techniques such as spin coating, drop casting, dip coating, spray coating, rod-coating, vacuum filtration, and slot-die coating may be used. In the example of the present application, the coating was performed by a spin coating method.

In step ii), the silver nanomaterial may be one or more of nanowires, nanoprotrusions, nanopillars, nanodimples, nanocubes, nanocoils, and nanoembossing. Although not limited thereto, nanowires may be suitable in terms of not reducing the light transmittance of the final film. When the roughness of the final film is high, light transmittance may decrease and haze may increase.

Step iii) is a step of oxidizing and/or segmenting the nanomaterial by heat treatment. When the heat treatment is performed, an Ag ₂ O film is formed, Ag ₂ O fine particles are generated, and the structure of the silver nanomaterial is collapsed to increase the surface area. Due to this, the antibacterial activity of the nanomaterial can be improved. In particular, antibacterial activity may be remarkably increased during heat treatment at a high temperature of 220° C. or higher. Although not limited thereto, the heat treatment temperature may be 220-300 ℃ suitable for improving antibacterial activity, 230-300 ℃ more suitable, 230-290 ℃ even more suitable, 230-280 ℃ may be most suitable. Although not limited thereto, when the heat treatment temperature exceeds 400° C., it is difficult to improve antibacterial activity due to an increase in desired segmentation and surface area due to melting, and light transmittance may also be reduced.

According to another aspect, there is provided a silver nanomaterial comprising 15% or more of Ag ₂ O, and at least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates.

The silver nanomaterial of the present application may contain 15% or more of Ag ₂ O. By including the Ag ₂ O by 15% or more, the antibacterial activity may be improved by increasing the specific surface area. As the content of Ag ₂ O is higher than 15%, antibacterial activity may be improved. It is limited thereto, the content of Ag ₂ O may be 15% or more suitable for improving antibacterial activity, 18% or more may be suitable, 20% or more may be more suitable, and 25% or more may be most suitable .

The silver nanomaterial may be suitable for improving antimicrobial activity when Ag ₂ O nanoparticles and Ag ₂ O aggregates are properly mixed.

The silver nanomaterial may be one or more of nanowires, nanoprotrusions, nanopillars, nanodimples, nanocubes, nanocoils, and nanoembossing. Although not limited thereto, nanowires may be suitable in terms of not reducing the light transmittance of the final film. When the roughness of the final film is high, light transmittance may decrease and haze may increase. In particular, a case in which the nanowires, Ag ₂ O nanoparticles, and Ag ₂ O aggregates are properly mixed may be suitable for improving antimicrobial activity.

The silver nanomaterial may be in the form of a film. In the case of the film form, it can be attached to an article by various known methods, and can easily impart antibacterial activity to the attached article.

At least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates may be formed by heat treatment at 220° C. or higher. Antimicrobial activity in which at least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates is formed by heat treatment may be improved.

As the heat treatment proceeds, Ag ₂ O silver fine particles are formed, and aggregates are formed in the portion where the nanowires intersect, and finally, all of the nanowires may be changed into aggregates. When Ag ₂ O nanoparticles and Ag ₂ O aggregates are properly mixed, it may be suitable for improving antimicrobial activity.

The silver nanomaterial may have an antibacterial activity improved by 25% or more compared to the silver nanomaterial before the heat treatment by the heat treatment. The antimicrobial activity may be different depending on the type of pathogen, but it may be possible to improve the antimicrobial activity by up to 50% or more.

According to another aspect, the base substrate; and silver nanomaterials described herein; including, silver nano-products are provided.

Although not limited thereto, the base substrate may be transparent. The transparent substrate may be glass or plastic. When the base substrate is a transparent substrate, antibacterial activity can be imparted to the article without affecting the appearance of the article when applied to the article.

Accordingly, the silver nanofilm according to an embodiment of the present application may be attached to metal and ceramic-based household products, art objects, medical devices, and windows to impart antibacterial activity while maintaining aesthetics.

In addition, the silver nano-product may be a transparent electrode. The transparent electrode means that a conductive film is formed on a transparent substrate, and since light can be transmitted, it is used in devices such as solar cells, display devices, and touch screen panels.

According to the configuration of the present application as described above, it is possible to provide a transparent electrode having remarkably improved antibacterial activity without loss of light transmittance, so that it can be applied to a touch screen panel used by multiple people to impart antibacterial activity.

According to another aspect, there is provided a silver nano product manufactured by the method for improving the antibacterial activity of the silver nano material of the present application.

The silver nano product manufactured by the method of improving the antibacterial activity of the silver nano material of the present application may have remarkably improved antibacterial activity while maintaining light transmittance.

Example

Hereinafter, the present invention will be described in more detail through examples.

1. Materials and Methods

1-1. Preparation and heat treatment of silver nanowire films

A silver nanowire dispersion solution (C3NANO corp., 0.3 weight percent concentration, ethanol solvent) was used. The silver nanowires have a thickness of 20-30 nm and a length of more than 20 μm, and are stacked with a thin layer of polyvinylpyrrolidone (PVP) with a thickness of 2-3 nm. Using this silver nanowire dispersion solution, spin coating was carried out at a rate of 7000 times/min for 30 seconds to prepare a 50-60 nm thick silver nanowire thin film on a 5 X 5 cm glass substrate.

After the coated glass was sufficiently dried at room temperature, it was heated in an air-oven at 200-450 ℃ (10 ℃ interval) for 30 minutes.

The higher the heating temperature, the shorter the segments were cut. The average lengths of silver nanowires upon heating at 200, 230, 250, and 280 °C were 8.3 (±3.6), 2.5 (±1.0), 0.5 (±0.3), and 0.4 (±0.3) nm, respectively. On the other hand, the silver nanowires heated at 200 °C did not have significant fragments and partially thickened, and when heated at a temperature above 280 °C, the silver nanowires became sharply thickened. In addition, it was observed that Ag ₂ O particles were dispersed on the silver nanowire substrate heated at 250° C., and the silver nanowire heated at 300° C. had smaller segments and formed agglomerates. The silver nanowires heated at 450° C. were melted, and the silver nanowires almost disappeared. The silver nanowire films heat-treated at 230 °C and 280 °C had significantly different segment shapes and seemed to be suitable in terms of specific surface area and antibacterial activity. Considering these results comprehensively, two heat treatment temperatures of 230 °C and 280 °C, which are expected to have strong antibacterial activity due to their large specific surface area, were selected and tested.

1-2. Characteristic measurement

The untreated and heat treated samples were subjected to surface shape image analysis and thickness analysis using an electron microscope and Alpha-step, respectively. Specifically, the surface morphology of the samples was measured by FE-SEM (JSM-7610F, JEOL co., Tokyo, Japan) at a voltage of 5 kV and a current of 10 μA under a high vacuum condition. The thickness was measured by Alpha-step (DektakXT, BRUKER co., Billerica, MA, USA).

Chemical qualitative and quantitative evaluation was performed by X-ray photoelectron spectroscopy (XPS, K-Alpha, Thermo Fisher co, Waltham, MA, USA). The spot size and energy step size of XPS analysis were 400 μm and 10 eV, respectively.

The optical properties were evaluated by UV-visible spectroscopy (UV-Vis, Cary 5000 UV-Vis-NIR, Agilent co, Santa Clara, CA, USA) and hazemeter (COH 400, Nippon Denshoku co, Tokyo, Japan). Haze refers to the degree of light scattering defined as the percentage of light scattered by 2.5 degrees or more with respect to the total transmitted light. The sheet resistance was measured with a Four probe.

1-3. antibacterial activity

Antibacterial activity was evaluated by JIS Z 2801 (film adhesion method). E. coli ( E. coli , KCTC, Jeongeup, Korea), a representative gram-negative bacterium, and Staphylococcus aureus ( S. aureus, KCTC, Jeongeup, Korea), a representative gram-positive bacterium, are cultured and diluted to obtain the maximum concentration specified in JIS Z 2801. An inoculum solution of 10 ⁷ CFU/mL corresponding to 10 times was prepared. After applying 0.4 mL of the inoculum solution to the test area of 4 X 4 cm ² of the test thin film and the control (standard film), the test area was covered with a sterile cover film. After that, it was placed in a sterile Petri dish and incubated for 30 minutes at 35 (± 1) °C and a high humidity environment. After incubation, the sample and cover film were washed thoroughly with Soybean Casein Digest Lecithin Polysorbate (SCDLP) broth solution to extract the bacteria remaining in the sample. The extract was diluted by 10-fold dilution with PBS (phosphate-buffered saline) solution 2-3 times. 1mL of the final dilution was mixed with warm agar, put in a sterile Petri dish, and inverted, incubated at 35 (± 1)°C, in a humid environment for 24 to 48 hours. After incubation, bacterial colonies grown in Petri dishes were visually counted. The number of bacteria was inversely calculated by considering the dilution factor from the observed colony number. Compared to the control group, how much the number of bacteria was reduced was expressed as a percentage and a log reduction rate.

2. Results

2-1. surface shape

1 is (a) a silver nanowire film (AgNW), (b) a silver nanowire film heat-treated at 230 °C (AgNW-230 °C), and (c) a silver nanowire film heat-treated at 280 °C (AgNW-230) ℃) is an FE-SEM planar image.

The thickness of the silver nanowire film produced by the spin coating method was 54 ± 6 nm, and it was confirmed by Alph-step and electron microscopy that it covered 26.5 ± 5.9% of the substrate area, respectively.

As shown in FIG. 1 , when observed with an electron microscope, it was observed that the silver nanowire was broken into shorter segments due to Rayleigh-Plateau instability as the heating temperature increased. During heat treatment at 280 °C, it was confirmed that newly formed particles smaller than 50 nm were dispersed on the substrate, and the silver nanowires were partially thickened. On the other hand, it was observed that silver nanowires heated at 200 °C became thicker than fragments. On the other hand, the silver nanowires heated at 250 °C showed a similar shape to the silver nanowires heated at 280 °C. Excessive self-coalescence induces fragmentation of silver nanowires.

2-2. oxidation state, optical properties, and sheet resistance

2 is a view showing (a) Ag 3d core-level XPS high-resolution spectrum, (b) transmittance and light, and (c) haze and total light transmittance of AgNW, AgNW-230 °C, and AgNW-280 °C.

As shown in (a) of Figure 2, it was confirmed that the oxidation of the silver nanowires progressed a lot when heated at a high temperature. When analyzed by X-ray photoelectron spectroscopy, the silver oxide (Ag ₂ O) component of the untreated, 230 °C and 280 °C thin film was 12.9%, 18.2%, and 25.1%, respectively. Particles smaller than 50 nm appearing when heat-treated at 280 °C are presumed to be Ag ₂ O. When silver nanowires are oxidized, nuclei are formed and Ag ₂ O is generated on the surface.

In addition, as shown in (b) of FIG. 2, optical and electrical properties were changed due to fragmentation and oxidation. Visible ray band transmittance and total light transmittance did not show a significant decrease, but the sheet resistance rapidly increased from 156 ohm/square to 10000 ohm/square or more.

2-3. antibacterial activity

3 shows S. aureus of AgNW, AgNW-230 °C, and AgNW-280 °C silver nanowires. and antibacterial activity against E. coli . (a) is a planar photograph of the cultured agar-plate and antibacterial activity, (b) is S. aureus and (c) is a graph showing the reduction ratio of E. coli . Bacterial experiments were performed by contacting the samples with an inoculum containing 4×10 ⁶ CFU of the experimental bacterial strain for 30 minutes.

As shown in FIG. 3 , the antibacterial activity was remarkably improved after heat treatment. The silver nanowire thin film and the inoculum containing bacteria were contacted for 30 minutes. For Staphylococcus aureus, 31.7% ± 2.4% (log reduction of 1.50 ± 0.38), 92.5% ± 2.2% (1.97 ± 0.34), 94.7% ± 1.7% for untreated, 230 °C and 280 °C thin films, respectively (1.98 ± 0.32) showed antibacterial activity (bacterial reduction rate). In the case of E. coli, 57.0% ± 3.0% (1.76 ± 0.48), 84.1% ± 4.9% (1.92 ± 0.69), and 98.7% ± 0.5% (1.99) antibacterial activity were shown. That is, it was confirmed that the antibacterial activity increased during heat treatment and the antibacterial activity was proportional to the heating temperature.

Figure 4 is a schematic diagram of the antibacterial mechanism of AgNW, AgNW-230 ℃, and AgNW-280 ℃. As shown in FIG. 4 , when considering the antibacterial mechanism of silver nanomaterials known in the art, 1) increase in specific surface area due to fragmentation and generation of Ag ₂ O nanoparticles during heat treatment and 2) surface oxidation (increase in Ag ₂ O component) As a result, it is expected that the antibacterial activity will be improved because the ion emission amount of Ag cations is increased. In addition, Ag ₂ O nanoparticles are presumed to have improved antibacterial activity because they also activate the antibacterial action that physically stabs and kills bacteria. That is, the chemical antibacterial action by the Ag cations released from the silver nanowires was improved by the heat treatment, and the physical antibacterial action by the Ag ₂ O nanoparticles was additionally worked, and the antibacterial power was strengthened.

The top-down method used herein can solve the problem of clustering of the existing bottom-up methods. With the bottom-up method, the specific surface area is small because the nanoparticles are agglomerated in solution by nature's providence. Therefore, it showed a lot of antibacterial performance in the form of a solution rather than a thin film. On the other hand, since there is no aggregation (surface area loss) after surface coating of silver nanowires in the form of wires that are difficult to aggregate with a thin film and heat treatment, a transparent antibacterial coating can be produced that improves antibacterial activity and does not significantly decrease transmittance.

Therefore, the silver nanowire film heat-treated at high temperature according to the present application is very promising as an antibacterial coating film that can be applied to various heat-resistant materials thanks to its strong antibacterial activity and transparency. That is, the present application can impart antibacterial activity to metal and ceramic-based household products, art objects, medical devices, and windows while maintaining aesthetics.

Although the present disclosure has been described in detail through specific examples, this is for the purpose of describing the present disclosure in detail, and the present disclosure is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present disclosure It is clear that the modification or improvement is possible. All simple modifications and variations of the present disclosure fall within the scope of the present disclosure, and the specific scope of protection of the present disclosure will be made clear by the appended claims.

Claims (12)

i) providing a base substrate;
ii) coating the silver nanomaterial on the base substrate; and
iii) heat-treating at 220 ° C. or higher; including,
A method for improving the antibacterial activity of silver nanomaterials.
The method of claim 1,
In step i), the base substrate is a transparent substrate, a method for improving antibacterial activity of silver nanomaterials.
According to claim 1,
In step ii), the silver nanomaterial is at least one of nanowires, nanoprotrusions, nanopillars, nanodimples, nanocubes, nanocoils, and nanoembossing, a method for improving antibacterial activity of silver nanomaterials.
According to claim 1,
Heat treatment at 230 to 300 ℃ in step iii), a method for improving the antibacterial activity of silver nanomaterials.
Ag ₂ O containing at least 15%,
A silver nanomaterial comprising at least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates.
6. The method of claim 5,
The silver nanomaterial is at least one of nanowires, nanoprotrusions, nanopillars, nanodimples, nanocubes, nanocoils, and nanoembossing, silver nanomaterials.
6. The method of claim 5,
The silver nanomaterial is in the form of a film, silver nanomaterial.
6. The method of claim 5,
At least one of Ag ₂ O nanoparticles and Ag ₂ O aggregates is formed by heat treatment at 220 ° C. or higher, silver nanomaterials.
9. The method of claim 8,
By the heat treatment, the antibacterial activity is improved by 25% or more compared to the silver nanomaterial before the heat treatment, silver nanomaterial.
base substrate; and
A silver nano-product comprising; the silver nanomaterial according to any one of claims 5 to 9.
11. The method of claim 10,
The base substrate is transparent, silver nano-product.
11. The method of claim 10,
A transparent electrode, a silver nano product.

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