KR102526277B1 - Stretchable gas barrier layered structure having wrinkles and method for manufacturing the same - Google Patents

Abstract

A stretchable gas barrier laminated structure having wrinkles, comprising: a stretchable substrate; and a film having gas barrier properties formed on the stretchable substrate, wherein the gas barrier film includes at least one wrinkle. The gas barrier laminated structure can implement high-performance barrier properties while having elasticity. In addition, it can be usefully used in various stretchable electronic devices because it can maintain its functionality while minimizing stress on the material due to deformation of the wrinkles.

Description

Stretchable gas barrier layered structure having wrinkles and method for manufacturing the same}

The present specification describes a stretchable gas barrier laminated structure having pleats and a manufacturing method thereof.

Next-generation electronic devices go beyond the limitations of hard substrates and require not only bending properties but also stretch functions that can freely change their shape in response to external stress.

To this end, existing bendable electronic devices have secured stability against bending deformation by thinning the thickness of a laminated structure or element, but it is difficult to secure elasticity with this approach.

On the other hand, the gas barrier film is an essential component used in various electronic devices, but pinholes and cracks occur when mechanically deformed by external stress, resulting in loss of functionality of the barrier material. Therefore, it has become a fatal obstacle to the implementation of stretchable electronic devices.

Korean Patent Application Publication No. 2011-83546

Large-scale pattern growth of graphene films for stretchable transparent electrodes Nature, 2009, 457, 706-710 Multifunctionality and control of the crumpling and unfolding of large-area graphene Nat. Maters, 2013, 12, 321 Super-Elastic Graphene Ripples for Flexible Strain Sensors ACS Nano 2011, 5 3645

In one aspect, an object of embodiments of the present invention is to provide a gas barrier laminated structure having fine wrinkles and a manufacturing method capable of realizing high-performance barrier properties while having elasticity.

In exemplary embodiments of the present invention, a stretchable gas barrier laminated structure having wrinkles is provided, comprising: a stretchable substrate; and a film having gas barrier properties formed on the stretchable substrate, wherein the gas barrier film includes at least one wrinkle.

In addition, in exemplary embodiments of the invention, an electronic device including the gas barrier laminated structure is provided.

Further, in exemplary embodiments of the present invention, the above-described gas barrier laminate structure manufacturing method includes providing a stretchable substrate; and forming a gas barrier film on the stretchable substrate and applying wrinkles to the gas barrier film.

According to exemplary embodiments of the present invention, as the gas barrier laminate structure is composed of a stretchable substrate and a gas barrier film and fine wrinkles are applied to the gas barrier film, it is possible to implement high-performance barrier properties while having elasticity. Although a high-performance stretchable gas barrier film could not be implemented using a conventional planar process or material, in the case of a gas barrier laminated structure having fine wrinkles according to exemplary embodiments of the present invention, deformation of the wrinkles causes stress to the material. It can be minimized while maintaining its functionality. Such a gas barrier laminated structure overcomes the defects of conductive materials and the limitations of the transfer process, and can be usefully utilized in various stretchable electronic devices.

1A is a schematic diagram showing a method for imparting fine wrinkles according to an exemplary embodiment of the present invention.
1B is a conceptual diagram illustrating a period and a height.
2 is a FE-SEM image showing a stretched graphene gas barrier laminated structure having wrinkles manufactured in an example of the present invention. Figure 2a shows that the pre-stress is applied at 5%, and Figure 2b is a tiled image obtained by rotating it.
3 is a FE-SEM image showing an elongated graphene gas barrier laminate structure having wrinkles manufactured in an example of the present invention. Figure 3a shows that the preliminary stress is applied to 10%, Figure 3b is a rotated image (tiled image).
4 is an AFM photograph showing an elongated graphene gas barrier laminate structure having coarse (rough) wrinkles in an embodiment of the present invention. FIG. 4A shows a pre-stress applied at 5%, and FIG. 4B shows a pre-stress applied at 10%.
5 is a result of a mechanical stability stretching test ( FIG. 5a ) and a mechanical stability twisting test ( FIG. 5b ) for the stretched graphene gas barrier laminate structure having wrinkles prepared in an example of the present invention. it's a graph
6 is a graph showing gas barrier properties of a graphene-based gas barrier laminated structure having fine wrinkles manufactured according to an example of the present invention.

In this specification, a gas barrier laminated structure means a structure including a gas barrier film and a stretchable substrate.

In this specification, a gas barrier film means a film having fine wrinkles on the surface, such as a single layer film.

In the present specification, fine wrinkles mean a shape having a constant wavelength and height (amplitude) on the surface of the gas barrier thin film (see FIG. 1B).

For example, the fine wrinkles may be a pattern having a height of several nanometers to hundreds of micrometers, for example, 1 nm or more to 500 μm or less, and a period ranging from tens of nanometers to hundreds of micrometers (eg, 10 nm or more to 500 μm or less). there is.

In addition, the shape of the wrinkles may be a unidirectional wrinkle shape with repetitive wrinkles in one direction, or may be a wrinkle shape that is repeatedly deformed in the x and y directions and has an isotropic shape, or irregular but with repeated high and low surfaces. It may include a pleated shape with a pattern.

Hereinafter, exemplary embodiments of the present invention are described in detail.

In exemplary embodiments of the present invention, a gas barrier laminated structure comprising: a substrate; It provides a gas barrier laminated structure including a gas barrier film formed on the substrate and having at least one wrinkle applied thereto.

In one exemplary embodiment, the substrate may be a stretchable substrate.

In an exemplary embodiment, a stress protection layer may be formed on the gas barrier layer.

In one exemplary embodiment, the shape of the wrinkles may be unidirectional fine wrinkles, isotropic wrinkles, or irregular but fine wrinkles.

In an exemplary embodiment, the fine wrinkles may be a pattern having a height of 1 nm or more and 500 μm or less and a period of 10 nm or more and 500 μm or less.

In one exemplary embodiment, the elasticity of the gas barrier laminated structure may be 1% or more and less than 1000%.

In an exemplary embodiment, the gas barrier properties of the gas barrier film itself may be 1x10 ^-4 g/m ² ·day or more as a property evaluated by water vapor transmission rate (WVTR).

Further, in exemplary embodiments of the present invention, a manufacturing method of the gas barrier laminate structure described above includes providing a substrate; and forming a gas barrier film on the substrate and providing wrinkles to the gas barrier film.

In an exemplary embodiment, the manufacturing method may include applying a tensile force to the stretchable substrate; The method may include forming a gas barrier film on the stretchable substrate to which the tensile force has been applied and providing wrinkles to the gas barrier film.

That is, in order to wrinkle the gas barrier film, first, pre-stress is applied to the stretchable substrate, the gas barrier film is laminated on the stretchable substrate to which the pre-stress is applied, and then the pre-stress is removed to form wrinkles on the gas barrier film. can At this time, in order to prevent excessive stress from being applied to the gas barrier film, a stress protection layer, preferably a flexible stress protection layer, is attached to the gas barrier film and laminated on the stretchable substrate.

1A is a schematic diagram showing a method for imparting fine wrinkles according to an exemplary embodiment of the present invention.

As shown in FIG. 1A, first, a substrate is formed of a stretchable polymer, and a pre-strain such as tensile force or contractive force is applied to the substrate. Subsequently, a gas barrier material (Fig. 1 shows graphene as an example) is placed on a substrate, and when the prestress is released (substrate release), a stretchable gas barrier film having fine wrinkles can be obtained.

In the case of the stretchable polymer used as the material of the stretchable substrate, various materials may be used.

In a non-limiting example, the stretchable substrate material includes a silicone-based elastic body having elasticity, a butadiene-based elastic body, a styrene-butadiene-based 　 elastic body, a Fluoro-based elastic body, A chloroprene-based elastomer, an ethylene propylene diene-based elastomer, an isobutylene isoprene-based elastomer, or a natural elastomer existing in nature may be used.

In addition, even if the shape is deformed by applying an external force to the object, it is possible to use a shape memory material having a property of returning to a desired shape under specific conditions (temperature, pH, pH, humidity, etc.).

As non-limiting examples, poly-norbornene, polyisoprene, styrene-butadiene copolymer, polyurethane, polyethylene, It includes, but is not limited to, polyester-based polymers. Examples of polyester-based shape memory polymers include polyphosphazene, polyanhydride, polyacetal, poly-ortho ester, polyphosphoester, and polyglycol. It may be selected from one or a combination of lead (polyglycolide), polycaprolactone (poly-ε-caprolactone), polylactide (polylactide), polycarbonate (polycarbonate), and polyamide (polyamide), but is not limited thereto. no.

Preferably, a shape memory polymer may be used as the stretchable material. When prestress is applied using a shape memory polymer, the substrate is fixed in a stretched state, and then when energy (light or heat, etc.) is applied, the shape memory polymer returns to its original state. It can be easily removed and wrinkled.

Meanwhile, in one embodiment, when the gas barrier film is laminated on the substrate to which the prestress is applied, a protective layer against stress may be formed on top of the gas barrier film of the gas barrier film.

That is, in order to minimize the stress applied to the gas barrier film material, a stress protection layer (or may also be referred to as a neutral stress layer) serving as a protection layer against stress during mechanical deformation is formed.

In exemplary embodiments, the stress protection layer may be formed on a substrate using a material having elasticity such as a substrate by a method such as spraying, spin coating, or lamination.

When tensile stress is applied from the outside, the stretchable gas barrier film prepared by the above method may have elasticity properties as fine wrinkles are smoothed out.

On the other hand, in another exemplary embodiment, the step of applying the wrinkles, applying a specific environment (temperature, pH, humidity, etc.) for applying a contractile force as an Ebi stress after laminating a gas barrier film on a substrate having elasticity, or It is possible to fabricate a barrier film having fine wrinkles by shrinking the substrate by providing the substrate.

On the other hand, in another exemplary embodiment, the step of providing wrinkles is to wrinkle the gas barrier film on a substrate having fine wrinkles by using a spray, spin coating, dry transfer process such as lamination or wet transfer, such as solution photolithography. It may be laminated to correspond to.

In another exemplary embodiment, the manufacturing method is to directly apply wrinkles through a method such as a difference in thermal expansion coefficient between laminated materials, adhesive force control between material interfaces, and a material internal stress application method when manufacturing a gas barrier laminated structure. can

Hereinafter, specific embodiments according to exemplary embodiments of the present invention will be described in more detail. However, the present invention is not limited to the following examples, and various types of embodiments can be implemented within the scope of the appended claims, and only the following examples will complete the disclosure of the present invention and at the same time, common in the art. It will be understood that the intention is to facilitate practice of the invention to those skilled in the art.

[Example]

Material

As the substrate, PDMS (polydimethylsiloxane), which is a silicon-based substrate, was used. At this time, the thickness of the substrate was 3 mm. As the gas barrier thin film, one layer, two layers, and four layers were stacked, and graphene was used. Poly(methyl methacrylate) (PMMA) with a thickness of 50 nm was used as the stress protection layer to be deposited on the graphene-based gas barrier thin film.

manufacturing process

After stretching the PDMS substrate by 5% (or 10%) through a stretching machine, a graphene barrier thin film having a PMMA stress protection layer laminated thereon was formed on the PDMS substrate using a spin coating method.

After that, the graphene-based gas barrier film (PMMA/Graphene/PDMS) was separated from the stretching machine to complete the graphene-based gas barrier film with fine wrinkles.

2 is a FE-SEM image showing a stretched graphene barrier film having wrinkles prepared in Example of the present invention. Figure 2a shows that the pre-stress is applied at 5%, and Figure 2b is a tiled image obtained by rotating it. For reference, in FIG. 2B, the upper wrinkled portion is a thin film serving as an actual gas barrier, and the lower portion is a stretchable substrate.

3 is a FE-SEM image showing a stretched graphene barrier film having wrinkles prepared in Example of the present invention. Figure 3a shows that the preliminary stress is applied to 10%, Figure 3b is a rotated image (tiled image). For reference, in FIG. 3B, the upper wrinkled portion is a thin film serving as an actual gas barrier, and the lower portion is a stretchable substrate.

As shown in FIGS. 2 and 3 , it can be seen that the graphene-based gas barrier film (PMMA/Graphene/PDMS) was well prepared.

4 is an atomic force microscope (AFM) photograph showing a stretched graphene barrier film having coarse wrinkles in an embodiment of the present invention. FIG. 4A shows a pre-stress applied at 5%, and FIG. 4B shows a pre-stress applied at 10%. In FIG. 4, the measuring option is to measure an area of 40 μm in the x direction and 40 μm in the y direction.

4 shows that the height of the wrinkles given 10% pre-stress is higher than that of the wrinkles given 5% pre-stress, and the height or width of the wrinkles can be controlled by adjusting the degree of pre-stress.

test method

After forming source and drain electrodes using liquid metal at both ends of the manufactured fine-wrinkled graphene-based gas barrier film, a stretching test was performed to observe the change in resistance using a stretching machine. For reference, in the stretching test, one side (left side or right side) of a sample having a rectangular shape is fixed with a clip, and the other opposite side (right side or left side) is pulled (i.e., tensile stress is applied) to measure the change in resistance. It is an observational test. The distance between the source and drain electrodes is 10 mm, and the rate of stretching the sample is 3 mm/s or less.

5 is a graph showing the results of a mechanical stability stretching test (FIG. 5a) and a mechanical stability twisting test (FIG. 5b) for a stretched graphene barrier film having wrinkles prepared in an example of the present invention. .

When no prestress is applied (Non-prestrain), since there are no wrinkles on the sample, it can be seen that the barrier film is damaged according to the sample length change rate due to tensile stress, and the resistance change rate increases dramatically (black).

On the other hand, in the sample formed with wrinkles through 5% pre-stress, wrinkles are straightened up to 5% length change rate and there is no damage. A sample subjected to 10% prestress can maintain a stable resistance change rate without damage up to 10% by the same principle.

As such, as a result of electrical characteristics, it was confirmed that the material had stability even under stretching stress. That is, finally, the elasticity of the barrier film may be increased or decreased as needed.

gas barrier properties

6 is a graph showing gas barrier properties of a graphene-based gas barrier laminated structure having fine wrinkles manufactured according to an example of the present invention.

Mocon equipment was used to measure the WVTR of the gas barrier, and the gas barrier film with wrinkles applied was fixed to the cradle, and moisture was continuously sprayed to one side, and after passing through the film, the sensor captured the amount of moisture detected on the other side. digitized.

Although non-limiting and exemplary embodiments of the present invention have been described above, the technical idea of the present invention is not limited to the accompanying drawings or the above description. It is obvious to those skilled in the art that various types of modifications are possible within the scope of the technical spirit of the present invention, and also, these types of modifications will fall within the scope of the claims of the present invention.

Claims (16)

A stretchable gas barrier laminated structure having pleats,
stretchable substrate; and
A film having gas barrier properties formed on the stretchable substrate;
The gas barrier layer includes at least one wrinkle, and further includes a stress protection layer on the gas barrier layer, wherein the stress protection layer minimizes stress applied to the film having gas barrier properties.
delete According to claim 1,
The stress protection layer has elasticity, the gas barrier laminate structure.
According to claim 1,
The wrinkles are unidirectional wrinkles or isotropic wrinkles or irregular patterned wrinkles, the gas barrier laminate structure.
According to claim 4,
The wrinkles are a pattern having a height of 1 nm or more and 500 μm or less and a period of 10 nm or more and 500 μm or less.
According to claim 1,
The gas barrier laminate structure has an elasticity of 1% or more and less than 1000%.
According to claim 1,
Gas barrier properties of the gas barrier film is WVTR 1x10 ^-4 g / m ² · day or more, the gas barrier laminated structure.
According to claim 1,
The gas barrier film is a graphene film, a laminated structure.
According to claim 1,
The stretchable substrate is made of a shape memory material.
An electronic device comprising the gas barrier laminated structure according to any one of claims 1 and 3 to 9.
providing a stretchable substrate;
forming a stress protection layer on the gas barrier film; and
Forming a gas barrier film on the stretchable substrate and providing wrinkles to the gas barrier film;
The stress protection layer minimizes the stress applied to the film having gas barrier properties, a gas barrier laminate structure manufacturing method
According to claim 11,
Applying the wrinkles may include applying a pre-stress to the stretchable substrate;
laminating a gas barrier film on the stretchable substrate to which a prestress has been applied; and
A method of manufacturing a gas barrier laminated structure comprising the steps of removing pre-stress.
delete According to claim 12,
The stretchable substrate is made of a shape memory polymer,
The method of manufacturing a gas barrier laminate structure, wherein the stretchable substrate is fixed in a stretchable state by applying a preliminary stress and restored to a pre-stretched state when energy is applied.
According to claim 11,
In the step of applying the wrinkles, the gas barrier layer is laminated on the stretchable substrate having the wrinkles to correspond to the substrate wrinkles.
According to claim 11,
In the step of applying the wrinkles, the gas barrier laminated structure manufacturing method allows the wrinkles to be directly applied during manufacturing of the gas barrier film.

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