KR102478178B1 - Flexible and stretchable electrode for skin attachment and manufacturing method thereof - Google Patents

Abstract

One embodiment of the present invention is a metal nanowire layer consisting of an amorphous network structure of metal nanowires coated with an antioxidant film; and a transfer support attached to at least one surface of the metal nanowire layer. Provides a skin-attached stretchable electrode comprising a. The skin-attachable metal nanowire electrode according to an embodiment of the present invention has excellent air permeability, elasticity, and oxidation stability.

Description

Flexible and stretchable electrode for skin attachment and manufacturing method thereof}

The present invention relates to a skin-attached stretchable electrode and a method for manufacturing the same, and more particularly, to a skin-attached stretchable electrode having excellent air permeability and high oxidation stability and a method for manufacturing the same.

Due to the rapidly growing fields of personal information platform and Internet of Things (IoT), the demand for flexible and stretchable electronic devices is increasing exponentially. Stretchable electronic devices can be manufactured in various forms, but the most used method among them is by far the method of patterning an electrode material on a stretchable material. A lot of research has been conducted on the stretchable material, and there are many commercialized products.

However, existing skin-attachable stretchable electrodes interfered with skin respiration and sweat discharge, resulting in a high risk of skin inflammation. In addition, conventional skin-attachable stretchable electrodes exhibited a decrease in conductivity due to oxidation of nano-metals due to sweat on the skin and oxygen in the air when attached to the skin.

Accordingly, a breathable stretchable electrode has been developed, but existing breathable skin-attached stretchable electrodes are manufactured through complex processes such as i) thermal evaporation after electrospinning, ii) weaving of conductive fibers, and the manufacturing method is complicated and expensive. I heard this a lot.

Therefore, it is necessary to develop an electrode that can reduce irritation to the skin while the manufacturing method is simple.

Republic of Korea Patent Registration No. 10-2019-0099902

A technical problem to be achieved by the present invention is to provide a skin-attachable stretchable electrode having excellent air permeability and high oxidation stability and a manufacturing method thereof.

The technical problem to be achieved by the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention provides a skin-attachable stretchable electrode.

In an embodiment of the present invention, the skin-attached stretchable electrode includes a metal nanowire layer in which metal nanowires coated with an antioxidant film have an amorphous network structure; and a transfer support attached to at least one surface of the metal nanowire layer. includes

In an embodiment of the present invention, the metal nanowire may include one or more selected from silver (Ag), gold (Au), platinum (Pt), copper (Cu), and iron (Fe).

In an embodiment of the present invention, the metal nanowire may have a diameter of 5 nm to 100 nm and a length of 5 μ to 100 μ.

In an embodiment of the present invention, the antioxidant film is ethylene vinyl alcohol (EVOH), polyvinyl alcohol (polyvinyl alcohol, PVA), cellulose (Cellulose), hydroxyethyl cellulose (Hydroxyethyl cellulose), polyvinylidene Polyvinylidene fluoride (PVDF), Polyacrylamide (PAM), Polyacrylic acid (PAA), Acrylonitrile butadiene styrene (ABS), Epoxy resin, Polyacrylo Nitrile (Polyacrylonitrile, PAN), polyaniline (PANI), polyetherimide (PEI), polyethylene glycol (PEG), or polyvinylpyrrolidone (PVP) may be included.

In an embodiment of the present invention, the transfer support may be a water-soluble tape containing poly(vinyl alcohol) (PVA).

In order to achieve the above technical problem, another embodiment of the present invention provides a method for manufacturing a skin-attached elastic electrode.

In an embodiment of the present invention, a method for manufacturing a skin-attached stretchable electrode includes applying a metal nanowire dispersion on a hydrophobic substrate; annealing the hydrophobic substrate coated with the metal nanowire dispersion to form a metal nanowire layer having an amorphous net structure; coating an anti-oxidation film on the surface of the metal nanowire layer; drying the metal nanowire layer coated with the antioxidant film; and attaching the dried metal nanowire layer to a transfer support to separate it from the hydrophobic substrate. includes

In an embodiment of the present invention, the metal nanowire may include one or more selected from silver (Ag), gold (Au), platinum (Pt), copper (Cu), and iron (Fe).

In an embodiment of the present invention, the applying of the metal nanowire dispersion and the coating of the antioxidant film may be performed by spray coating, bar coating, spin coating, or roll coating. It may be performed by coating, dip coating, flow coating or doctor blade coating.

In an embodiment of the present invention, the annealing may be performed at a temperature of 130 ° C to 250 ° C for 3 minutes to 20 minutes.

In an embodiment of the present invention, the antioxidant film is ethylene vinyl alcohol (EVOH), polyvinyl alcohol (polyvinyl alcohol, PVA), cellulose (Cellulose), hydroxyethyl cellulose (Hydroxyethyl cellulose), polyvinylidene Polyvinylidene fluoride (PVDF), Polyacrylamide (PAM), Polyacrylic acid (PAA), Acrylonitrile butadiene styrene (ABS), Epoxy resin, Polyacrylo Nitrile (Polyacrylonitrile, PAN), polyaniline (PANI), polyetherimide (PEI), polyethylene glycol (PEG), or polyvinylpyrrolidone (PVP) may be included.

In an embodiment of the present invention, the transfer support may be a water-soluble tape containing poly(vinyl alcohol) (PVA).

Since the skin-attachable metal nanowire electrode according to an embodiment of the present invention has an amorphous net structure, it has excellent air permeability and may not irritate the skin.

In addition, since the elasticity is greatly improved, the resistance does not greatly increase compared to the initial resistance.

In addition, oxidation stability can be very excellent even when the skin sweats by coating the nanowire with an antioxidant film.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a schematic diagram of a skin-attached flexible electrode according to an embodiment of the present invention.
Figure 2 is a flow chart of a method for manufacturing a skin-attached elastic electrode according to an embodiment of the present invention.
Figure 3 is a schematic diagram of a method for manufacturing a skin-attached elastic electrode according to an embodiment of the present invention.
4 is a SEM image of a skin-attached flexible electrode according to an embodiment of the present invention.
5 is a result of a flexibility test of a skin-attached flexible electrode according to an embodiment of the present invention.
6 is a result of an oxidation stability test of a skin-attached flexible electrode according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and, therefore, is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this is not only "directly connected", but also "indirectly connected" with another member in between. "Including cases where In addition, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

A skin-attachable stretchable electrode according to an embodiment of the present invention will be described.

1 is a schematic diagram of a skin-attached flexible electrode according to an embodiment of the present invention.

Referring to FIG. 1, the skin-attached stretchable electrode according to an embodiment of the present invention includes a metal nanowire layer 10 in which metal nanowires 11 coated with an antioxidant film 12 have an amorphous net structure; and a transfer support 20 attached to at least one surface of the metal nanowire layer. includes

First, the metal nanowire layer 10 has an amorphous mesh structure of metal nanowires 11 coated with an antioxidant film 12 .

The metal nanowire 11 may include one or more selected from among silver (Ag), gold (Au), platinum (Pt), copper (Cu), and iron (Fe).

The metal nanowires 11 may be formed of one metal or a mixture of two or more metals.

For example, the metal nanowires 11 may be silver nanowires.

The silver (Ag) nanowire is easy to supply and demand because silver (Ag) is a metal that exists in large quantities in nature, and has the lowest electrical resistance among metals, and even with a very small amount of use, electrical conductivity comparable to ITO and transparency of 85% or more has the advantage of being able to represent

A mixture of two or more types of metal nanowires may be used for the metal nanowires 11 in consideration of conductivity, economy, and the like.

The metal nanowire 11 may have a diameter of 5 nm to 100 nm and a length of 5 μ to 100 μ.

The antioxidant film 12 is made of ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVA), cellulose, hydroxyethyl cellulose, polyvinylidene fluoride , PVDF), Polyacrylamide (PAM), Polyacrylic acid (PAA), Acrylonitrile butadiene styrene (ABS), Epoxy resin, Polyacrylonitrile, PAN), polyaniline (PANI), polyetherimide (PEI), polyethylene glycol (PEG), or polyvinylpyrrolidone (PVP).

The anti-oxidation film 12 (coating layer represented by yellow in FIG. 1) is coated to cover the surface of the metal nanowires 11 to prevent the metal nanowires 11 from being oxidized by blocking contact with air. can

Since the antioxidant film 12 does not close between strands of the metal nanowires 11, the metal nanowire layer 10 can maintain an amorphous random mesh structure, and thus the metal nanowire layer 10 When (10) is attached to the skin, it has excellent air permeability, so sweat from the skin is smoothly discharged and evaporated, and air and skin can be well contacted, so that troubles such as skin redness, which is a side effect of the prior art, can be prevented. In addition, the side effect of unstable contact due to sweat can be prevented.

In addition, since the metal nanowire layer 10 has an amorphous net structure, it has excellent elasticity compared to nanowire electrodes attached to a conventional film, and has greater oxidation stability than the conventional film structure even when the skin sweats. can be improved

Next, the transfer support 20 may be attached to at least one surface of the metal nanowire layer 10, and the transfer support may be separated when the electrode is attached to the skin and used.

The transfer support may be a water soluble film (tape) containing poly(vinyl alcohol) (PVA).

The polyvinyl alcohol (PVA, PVOH) is a colorless and odorless synthetic polymer that has high tensile strength, flexibility, non-toxicity and adhesive properties, is soluble in water, and has excellent oil resistance and air barrier properties.

The transfer support 20 serves to separate the metal nanowire layer 10 from the hydrophobic substrate before the metal nanowire layer 10 is attached to the skin, and to support the separated metal nanowire layer 10. can do.

In addition, the transfer support 20 may be removed by dissolving in water after transferring (attaching) the metal nanowire layer 10 to the skin.

A method for manufacturing a skin-attachable elastic electrode according to another embodiment of the present invention will be described.

Figure 2 is a flow chart of a method for manufacturing a skin-attached elastic electrode according to an embodiment of the present invention.

Figure 3 is a schematic diagram of a method for manufacturing a skin-attached elastic electrode according to an embodiment of the present invention.

Referring to FIGS. 2 and 3 , a method for manufacturing a skin-attached flexible electrode according to another embodiment of the present invention includes applying a metal nanowire dispersion on a hydrophobic substrate (S100); annealing the hydrophobic substrate coated with the metal nanowire dispersion to form a metal nanowire layer having an amorphous network structure (S200); coating an anti-oxidation film on the surface of the metal nanowire layer (S300); drying the metal nanowire layer coated with the antioxidant film (S400); and attaching the dried metal nanowire layer to a transfer support to separate it from the hydrophobic substrate (S500); includes

In the first step, a metal nanowire dispersion is applied on a hydrophobic substrate (S100).

The hydrophobic substrate may be a hydrophobic polymer substrate, a hydrophobic polymer coated substrate, or a glass substrate, and is not limited thereto as long as it is a hydrophobic substrate applied to the present technical field.

For example, the hydrophobic polymer is PTFE (polytetrafluoroethylene), PET (polyethylene terephthalate), PVDF (polyvinylidene fluoride), PSF (polysulfone), PES (polyethersulfone), PEI (polyether mid), PI (polyimide), PE (polyethylene), PP (polypropylene) or PA (polyamide).

The metal nanowire may include one or more selected from among silver (Ag), gold (Au), platinum (Pt), copper (Cu), and iron (Fe).

The metal nanowires may be formed of one metal or a mixture of two or more metals in consideration of conductivity and economy.

The metal nanowire dispersion may further include metal nanowires and additives such as a dispersing agent, a binder, a surfactant, a wetting agent, and a leveling agent.

For example, when using a silver (Ag) nanowire solution, polyvinylpyrrolidone (PVP) can be used as a surfactant to control the growth of silver (Ag) nanowires, and the use of polyvinylpyrrolidine (Ag) The dispersion of nanowires can be improved to facilitate application.

In addition, as the solvent of the metal nanowire solution, for example, in addition to water, alcohols such as ethanol, isopropanol, and butanol, glycols such as ethylene glycol and glycerin, ethyl acetate, butyl acetate, methoxypropyl acetate, carbitol acetate, Acetates such as ethyl carbitol acetate, methyl cellosolve, butyl cellosolve, diethyl ether, tetrahydrofuran, ethers such as dioxane, methyl ethyl ketone, acetone, dimethylformamide, 1-methyl-2- Ketones such as pyrrolidone, hydrocarbons such as hexane, heptane, dodecane, paraffin oil and mineral spirits, aromatics such as benzene, toluene and xylene, and halogen-substituted solvents such as chloroform, methylene chloride and carbon tetrachloride, aceto Nitrile, dimethyl sulfoxide, or a mixed solvent thereof may be used.

The step of applying the metal nanowire dispersion may include spray coating, bar coating, spin coating, roll coating, dip coating, flow coating, or doctor blade coating. (doctor blade) coating.

For example, the step of applying the metal nanowire dispersion may be performed by spray coating (FIG. 3(a)).

For example, the spray coating may be applied on the hydrophobic substrate with a nozzle size of 0.2 to 1.5 and a pressure of 0.5 to 3 kgf/cm 2 using a spray coater.

In a second step, the hydrophobic substrate coated with the metal nanowire dispersion is annealed to form a metal nanowire layer having an amorphous network structure (S200) (FIG. 3(b));

The annealing may be performed at a temperature of 130 °C to 250 °C for 3 to 20 minutes.

For example, the annealing may be performed at 170° C. for 10 minutes.

In the third step, an antioxidant film is coated on the surface of the metal nanowire layer (S300).

The antioxidant film is ethylene vinyl alcohol (EVOH), polyvinyl alcohol (polyvinyl alcohol, PVA), cellulose, hydroxyethyl cellulose, polyvinylidene fluoride (PVDF) , Polyacrylamide (PAM), Polyacrylic acid (PAA), Acrylonitrile butadiene styrene (ABS), Epoxy resin, Polyacrylonitrile (PAN), It may include polyaniline (PANI), polyetherimide (PEI), polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP).

The step of coating the antioxidant film is spray coating, bar coating, spin coating, roll coating, dip coating, flow coating, or doctor blade coating. ) coating.

For example, the step of coating the antioxidant film may be performed by bar coating (FIG. 3(c)).

For example, the bar coating may be applied at a rate of 3 mm/sec to 50 mm/sec using a bar coater.

The anti-oxidation layer may be coated while covering the surface of the metal nanowires to prevent the metal nanowires from being oxidized by blocking contact with air.

Since the antioxidant film does not close between strands of the metal nanowires, the metal nanowire layer can maintain an amorphous random mesh structure, and thus, when the metal nanowire layer is attached to the skin, air permeability is excellent, Sweat from the skin is smoothly discharged and evaporated, and air and skin can be well contacted, so troubles such as skin redness, which is a side effect of the prior art, can be prevented. In addition, the side effect of unstable contact due to sweat can be prevented.

In addition, the metal nanowire layer has excellent elasticity compared to nanowire electrodes attached to a conventional film due to its amorphous net structure, and even when the skin sweats, oxidation stability can be greatly improved compared to the conventional film structure. .

In the fourth step, the metal nanowire layer coated with the antioxidant film is dried (S400) (FIG. 3(d)).

The drying may be performed at 80° C. for 60 minutes, for example.

In the fifth step, the dried metal nanowire layer is attached to a transfer support and separated from the hydrophobic substrate (S500) (FIG. 3(e),(f)).

When an adhesive transfer support is attached to one surface of the dried metal nanowire layer on the hydrophobic substrate (FIG. 3(e)) and then peeled off, the dried metal nanowire layer is attached to the transfer support and is separated from the hydrophobic substrate. It can be separated apart (Fig. 3(f)).

The transfer support may be a water soluble film (tape) containing poly(vinyl alcohol) (PVA).

The polyvinyl alcohol (PVA, PVOH) is a colorless and odorless synthetic polymer that has high tensile strength, flexibility, non-toxicity and adhesive properties, is soluble in water, and has excellent oil resistance and air barrier properties.

The transfer support may serve to separate the metal nanowire layer from the hydrophobic substrate before attaching the metal nanowire layer to the skin and support the separated metal nanowire layer.

In a subsequent step, when attaching the metal nanowire layer to the skin and using it as an electrode, the transfer support transfers the metal nanowire layer to the skin (FIG. 3(g)), and then dissolves in water and removes it (FIG. 3(h)).

manufacturing example

First, a silver (Ag) nanowire dispersion was applied by spray coating on a glass substrate coated with PTFE. Next, the surface of the substrate coated with the silver nanowire dispersion was sintered at 170° C. for 10 minutes to form a silver nanowire layer. Next, EVOH was bar-coated as an antioxidant film on the surface of the silver nanowire layer. Next, the EVOH-coated silver nanowire layer was dried. Next, the dried silver nanowire layer was attached to a PVA water dissociable tape and then peeled off to separate the silver nanowire layer from the PETE-coated glass substrate to prepare a skin-attachable stretchable electrode.

comparative example

A silver (Ag) nanowire dispersion was applied by spray coating on a glass substrate coated with PTFE. Next, the surface of the substrate coated with the silver nanowire dispersion was sintered at 150° C. for 10 minutes to form a silver nanowire layer. Next, PDMS was spin-coated as an antioxidant film on the surface of the silver nanowire layer. Next, the silver nanowire layer coated with PDMS was dried. Next, the dried silver nanowire layer was attached to a PVA water dissociable tape and then peeled off to separate the silver nanowire layer from the PTFE-coated glass substrate to prepare a skin-attachable stretchable electrode.

Experimental example

4 is a SEM image of a skin-attached flexible electrode according to an embodiment of the present invention.

Referring to FIG. 4 , it can be confirmed that the skin-attached stretchable electrode has an amorphous network structure.

comparative example
(PDMS film substrate) manufacturing example
(EVOH-coated silver nanowire amorphous net substrate) Air permeability (measured after 24 hours of application) Skin redness observed Skin redness not observed Oxidative stability (measured after standing at 40°C for 24 hours in artificial sweat) Increased by more than 20% compared to initial resistance Increased by less than 2% compared to initial resistance Stretchable electrode properties (measured at 40% strain) Increased by more than 15% compared to initial resistance Increased by less than 5% compared to initial resistance

Table 1 is a characteristic evaluation table of Comparative Examples and Preparation Examples. FIG. 5 is a flexibility test result of a skin-attachable flexible electrode according to an embodiment of the present invention.

Referring to Table 1 and FIG. 5, when stretching at a strain of about 40%, the electrical conductivity compared to the initial resistance increased by less than 5%, and the electrical conductivity did not change significantly until stretching at a strain of about 70%. there is.

6 is a result of an oxidation stability test of a skin-attached flexible electrode according to an embodiment of the present invention.

Referring to FIG. 6 , it can be seen that the silver nanowire stretchable electrode coated with the EVOH anti-oxidation film exhibits higher oxidation stability than the silver nanowire stretchable electrode in the form of a PDMS film substrate.

Since the skin-attachable metal nanowire electrode according to an embodiment of the present invention has an amorphous net structure, it has excellent air permeability and may not irritate the skin.

In addition, since the elasticity is greatly improved, the resistance does not greatly increase compared to the initial resistance.

In addition, oxidation stability can be very excellent even when the skin sweats by coating the nanowire with an antioxidant film.

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof should be construed as being included in the scope of the present invention.

10: metal nanowire layer
11: metal nanowire
12: antioxidant film
20: transfer support

Claims (11)

delete delete delete delete delete coating a metal nanowire dispersion on a hydrophobic substrate;
annealing the hydrophobic substrate coated with the metal nanowire dispersion to form a metal nanowire layer having an amorphous net structure;
coating an anti-oxidation film on the surface of the metal nanowire layer;
drying the metal nanowire layer coated with the antioxidant film; and
separating the dried metal nanowire layer from the hydrophobic substrate by attaching it to a transfer support; Skin-attached stretchable electrode manufacturing method comprising a. According to claim 6,
The metal nanowires are skin-attached stretchable electrode manufacturing method characterized in that it comprises at least one selected from silver (Ag), gold (Au), platinum (Pt), copper (Cu) and iron (Fe). According to claim 6,
The step of applying the metal nanowire dispersion and the step of coating the antioxidant film may include spray coating, bar coating, spin coating, roll coating, dip coating, Skin-attached stretchable electrode manufacturing method, characterized in that carried out by flow (flow) coating or doctor blade (doctor blade) coating. According to claim 6,
In the step of annealing the hydrophobic substrate coated with the metal nanowire dispersion to form a metal nanowire layer having an amorphous network structure,
The annealing is skin-attached stretchable electrode manufacturing method, characterized in that carried out for 3 minutes to 20 minutes at a temperature of 130 ℃ to 250 ℃. According to claim 6,
In the step of coating an antioxidant film on the surface of the metal nanowire layer,
The antioxidant film is ethylene vinyl alcohol (EVOH), polyvinyl alcohol (polyvinyl alcohol, PVA), cellulose, hydroxyethyl cellulose, polyvinylidene fluoride (PVDF) , Polyacrylamide (PAM), Polyacrylic acid (PAA), Acrylonitrile butadiene styrene (ABS), Epoxy resin, Polyacrylonitrile (PAN), Polyaniline (PANI), polyetherimide (PEI), polyethylene glycol (PEG) or polyvinylpyrrolidone (Polyvinylpyrrolidone, PVP) characterized in that it comprises a skin-attached stretchable electrode manufacturing method. According to claim 6,
In the step of attaching the dried metal nanowire layer to a transfer support to separate it from the hydrophobic substrate,
The transfer support is a skin-attached stretchable electrode manufacturing method, characterized in that the water-soluble tape containing polyvinyl alcohol (Poly (vinyl alcohol), PVA).

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