KR101641207B1

KR101641207B1 - Liquid and Vapor Proof Superhydrophobic Polyimide Film and Manufacturing Method of the Same

Info

Publication number: KR101641207B1
Application number: KR1020160017042A
Authority: KR
Inventors: 김용진; 송준엽; 이재학; 김승만; 이상일
Original assignee: 한국기계연구원
Priority date: 2016-02-15
Filing date: 2016-02-15
Publication date: 2016-07-20

Abstract

The present invention relates to a polyimide film having an impermeable and superhydrophobic property and a method of manufacturing the polyimide film. More particularly, the present invention relates to a polyimide film having a nano pattern master mold, A second step S200 of depositing a sacrificial layer 200 through an atomic layer deposition (ALD) on the master mold processed by the first step S100, A third step S300 of coating the polymer layer 300 on the sacrificial layer 200 deposited by the step S200, a sacrificial layer 200 beneath the polymer layer 300 and a step of etching the substrate 100 The atomic layer 400 is coated on the surface of the sacrificial layer 200 and the polymer layer 300 on which the substrate 100 is etched by the fourth step S400 and the fourth step S400, (S500). &Lt; RTI ID = 0.0 > A < / RTI > .

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a polyimide film having an impermeable property and a superhydrophobic property,

The present invention relates to a polyimide film having non-permeability and superhydrophobicity and a method for producing the same, and more particularly, to a polyimide film having a nano-pattern master mold having a large aspect ratio by using a surface treatment by physical processing, And a polyimide film is coated on the mold to transfer nanopatterns to have superhydrophobicity. In addition, the surface of the polyimide film is coated with an atom layer using ALD (Atomic Layer Deposition), so that it has resistance not only to the liquid phase but also to the vapor phase. The present invention also relates to a polyimide film having non-permeability and superhydrophobicity capable of being mass-produced by repeatedly performing a polyimide film production process through one master mold, and a method for producing the same.

When the water droplet contacts the surface of the conductor, the contact angle of the water droplet is defined as hydrophobic in the range of 70 to 150 ° and defined as super-hydrophobic in the case of 150 ° or more. Particularly, on a solid surface having a water contact angle of 170 ° or more, the water droplet rolls on its surface and keeps a clean state long without leaving a trace of contact with water.

In other words, even after flowing the aqueous solution into the container having the super-hydrophobic surface, it is possible to maintain a completely clean state without leaving a droplet of the solution on the inner wall of the container.

In general, hydrophobicity is expressed by covering a surface with a molecule having a low surface tension, but it is difficult to express a superhydrophobic molecule only by a molecule having a low surface tension.

On the other hand, there are many kinds of organisms that exhibit super-hydrophobicity. For example, leaves of rice, rice, cabbage and the like have a super water-repellent ability to completely bounce water droplets.

In detail, it is known that the superhydrophobicity of the soft leaves is deeply related to the surface structure of the leaves. That is, the nanofibers spread over the entire surface to form a surface layer, and the outermost layer of irregularities of micron (mu m) size as the nanofibers are formed at a certain distance. On the surface of these nanofibers, There is a wax. As a result, the water molecule can not adhere to the surface of the softened leaf, so it rolls on the surface of the softened leaf and develops a so-called self-cleaning function that reduces surface contamination by the force of the cloud. In order to exhibit such superhydrophobicity, it is suggested that surface roughness, that is, control of the surface structure and shape at the nano-dimension is important.

The structural principle of superhydrophobic expression, also known as the effect of kite, has become a guideline for the development of many artificial quasi-structure design methods, and a variety of techniques have been developed that show various superficial hydrophobicity for years with progress of nanomaterials.

Although many superhydrophobic related art documents frequently mention a superhydrophobic film and their fabrication methods, they often correspond to a method of processing the surface roughness on the surface of the substrate, and the surface treatment processing step is complicated and expensive .

In addition, in the case of an organic polymer-based superhydrophobic surface, although the cost is low, there is a practical problem because the obtained polyhydrophobic surface has low solvent resistance and corrosion resistance.

In addition, some structures that temporarily exhibit a high contact angle only and exhibit super-hydrophobicity may lose superhydrophobicity if water is immersed for a long time.

In addition, even if it has a superhydrophobic property and is not resistant to vapor and oxygen in the vapor state, that is to say, if it is not non-impregnated, vapor phase water vapor and oxygen can pass through the thin film and cause organic matter Problems that cause problems are included.

In U.S. Patent Publication No. 2013-0115420 (titled: NANO COMPOSITE WITH SUPERHYDROPHOBIC SURFACE AND METHOD OF MANUFACTURING THE SAME, hereinafter referred to as "Prior Art 1"), a thermosetting film is formed on a thermoplastic film by a mechanical method A method for forming a nanopattern is disclosed.

Since the prior art 1 forms a nanopattern through a mechanical method on a thermoplastic film, it is difficult for the formed nanopattern to have a large aspect ratio, resulting in a problem of having a super-hydrophobic limit.

In addition, US Patent No. 8557335 (entitled METHOD FOR MANUFACTURING AN EXTREMELY HYDROPHOBIC SURFACE, hereinafter referred to as " Prior Art 2 ", issued on Oct. 13, 2013) forms an uneven surface on the surface through a mechanical method, 1, the formed pattern is difficult to have a large aspect ratio and thus has a problem of having a limit of super-hydrophobicity.

U.S. Published Patent Application No. 2013-0115420 (titled: NANO COMPOSITE WITH SUPERHYDROPHOBIC SURFACE AND METHOD OF MANUFACTURING THE SAME) U.S. Patent No. 8557335 (entitled METHOD FOR MANUFACTURING AN EXTREMELY HYDROPHOBIC SURFACE)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide a master mold of a nano pattern having a large aspect ratio by using a surface treatment by physical processing, And the polyimide film is coated on the mold to transfer nanopatterns to have superhydrophobicity. In addition, the surface of the polyimide film is coated with an atom layer using ALD (Atomic Layer Deposition), so that it has resistance not only to the liquid phase but also to the vapor phase. The present invention also provides a polyimide film having non-permeability and superhydrophobicity capable of repeatedly performing a polyimide film production process through one master mold, and mass production thereof, and a method for producing the same.

A method of fabricating a polyimide film having a non-permeability and a super hydrophobicity according to an embodiment of the present invention includes a first step (S100) of processing a master mold of a nano pattern according to a predetermined size on a substrate (100) A second step S200 of depositing a sacrificial layer 200 through an atomic layer deposition (ALD) on the master mold processed by the first step S100, the second step S200, A third step S300 of coating the polymer layer 300 on the sacrificial layer 200 deposited by the first step 300 and a fourth step S300 of etching the sacrificial layer 200 and the substrate 100 below the polymer layer 300 (S500) of coating the surface of the polymer layer (300) on which the sacrifice layer (200) and the substrate (100) are etched by an atomic layer deposition method by an atomic layer deposition method by the fourth step (S400) .

At this time, the first step (S100) is a step of machining a master mold of a nanopattern having a large aspect ratio through fine processing using a femtosecond laser or DRIE (Deep Reactive Ion Etching) .

At this time, in the second step S200, plasma-enhanced ALD (atomic layer deposition) is performed by atomic layer deposition using at least one of SiO ₂ , SiNx, and Al ₂ O ₃ as the sacrifice layer 200, Or the sacrificial layer 200 is deposited using thermal ALD.

In this case, the third step S300 may be performed by using a polyimide as the polymer layer 300 and forming a polymer layer (not shown) using any one of a spin coating method, a slot coating method, a bar coating method and a molding coating method. 300). &Lt; / RTI >

In this case, the fourth step S400 may be performed by using any one of hydrofluoric acid (HF), buffered oxide etchant (BOE), and phosphoric acid solution, The sacrificial layer 200 and the substrate 100 are etched.

At this time, the fifth step S500 is characterized in that the atomic layer deposition is performed using plasma-enhanced atomic layer deposition (plasma enhanced atomic layer deposition) or thermal ALD deposition.

The non-impermeable and superhydrophobic polyimide film of the present invention having the above-described structure and the method of manufacturing the same have the advantage that the nanopattern formed on the PI layer is formed at a ratio of 1: Since it has a large aspect ratio of 5 or more, a super hydrophobic polyimide film having a CA (contact angle) of 150 ° or more and a SA (sliding angle) hysteresis of 10 ° or less can be produced.

In addition, there is an advantage that high reliability, repeatability and expandability can be achieved by utilizing microfabrication technology.

In addition, the atomic layer coating on the surface of the polyimide film improves the resistance to water vapor and oxygen in the gaseous state, and thus a polyimide film having both impermeability and super-hydrophobicity can be produced.

In addition, the organic material can be effectively protected from the liquid phase and the vapor phase, and has an advantage of being excellent in applicability as a thin film encapsulation film.

In addition, due to its strong resistance to liquid phase and vapor phase, it has an advantage of excellent mechanical reliability, and it is advantageous to use in various fields by lamination technology.

FIG. 1 is a flowchart illustrating a method of manufacturing a polyimide film having a non-permeable and super-hydrophobic property according to an embodiment of the present invention.
FIG. 2 is a view showing an embodiment of each step of a method for producing a polyimide film having non-permeability and super-hydrophobicity according to an embodiment of the present invention.
FIGS. 3 and 4 are illustrations of a polyimide film having non-permeability and super-hydrophobicity according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a polyimide film having a non-impermeable property and a super-hydrophobic property according to the present invention will be described in detail with reference to the accompanying drawings. The following drawings are provided as examples for allowing a person skilled in the art to sufficiently convey the idea of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms. In addition, like reference numerals designate like elements throughout the specification.

In this case, unless otherwise defined, technical terms and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the following description and the accompanying drawings, A description of known functions and configurations that may unnecessarily obscure the description of the present invention will be omitted.

As shown in FIG. 1, a method of fabricating a polyimide film having non-penetrability and superhydrophobicity according to an embodiment of the present invention includes a first step (S100) of processing a master mold according to a preset size on a substrate 100, A second step S200 of depositing a sacrificial layer 200 on the master mold, a third step S300 of coating the polymer layer 300 on the sacrificial layer 200, a third step S300 of coating the sacrificial layer 200 on the master mold, A fourth step S400 of etching the sacrificial layer 200 and a fifth step S500 of coating an ALD layer on the PI surface on which the sacrificial layer 200 and the substrate 100 are etched. The embodiment of each step of the method for producing a polyimide film having non-permeability and super-hydrophobicity according to the embodiment.

The non-impermeable and super-hydrophobic polyimide film prepared by the method of producing a non-impermeable and super-hydrophobic polyimide film by using a surface treatment by physical processing, excluding the chemical treatment method as far as possible, (SA) contact angles of more than 150 ° and SA (Sliding Angle) Hysteresis of less than 10 °. In addition to having super-hydrophobic and super-water-repellent properties, It is a polyimide film having high resistance and impermeability.

Through the polyimide film having the impermeability and superhydrophobicity of the present invention, the self-cleaning function can be applied to the flexible solar cell panel and the display which are not soiled, and can be protected from the liquid phase and the vapor phase.

To learn more about each step,

The first step S100 can process the master mold of the nanopattern according to the size set in advance on the substrate 100, that is, according to the size desired by the operator. Depending on the size desired by the operator, it can be processed in a large area.

The substrate 100 may be a sheet metal or a silicon wafer. However, it is possible to use any substrate that can process patterns and has no damage in the etching process.

As shown in FIG. 2A, the first step S100 may be performed using a femtosecond laser or a deep processing using DRIE (Deep Reactive Ion Etcher) to produce a large aspect ratio of 1: 5 or more, And the droplet on the contact surface of the nanopattern is preferably arranged so as to maintain the superhydrophobic state of the Cassie-Baxter. For example, there are a lattice arrangement of a linear structure or a repeated arrangement of independent pillar structures, and a variety of structures can be formed depending on the shape of the master mold.

Also, it is possible to manufacture a large-area superhydrophobic polyimide film in accordance with the size of the master mold of the nano pattern processed in the substrate 100 in the first step S100.

In the second step S200, the sacrificial layer 200 may be deposited on the master mold processed through the first step S100 by atomic layer deposition (ALD). The atomic layer deposition method is a method of growing a thin film by injecting a raw material containing an ALD metal and a reactive gas in a crossing manner. The thin film can be controlled while repeating the growth of the atomic unit thin film by reacting the raw material and the gas.

Therefore, since the atomic unit thin film is deposited, it has an advantage that it can be uniformly coated on the nanopattern formed with fine pitch and high aspect ratio. That is, even if the polyimide film is separated from the master mold by a sacrificial layer etching through a subsequent process with a small thickness of the uniformly coated sacrificial layer, the pattern resolution loss transmitted to the surface of the polyimide film from the master mold surface can be minimized have.

The first stage 2 (S200), the sacrificial layer 200 as SiO _2, SiNx and Al ₂ O _3, at least any one is preferred, plasma atomic layer deposition of-enhanced ALD (Plasma-Enhanced ALD) or Thermal ALD can be used to deposit the sacrificial layer 200 to a desired thickness on the master mold according to the master mold shape of the nanopattern as shown in FIG. 2 (b).

In the third step S300, the polymer layer 300 may be coated on the sacrificial layer 200 deposited by the second step S200, as shown in FIG. 2C. Here, it is preferable to use a polyimide as the polymer layer 300, and both the colorless type and the yellow type can be used as the polyimide.

The third step S300 may include a spin coating method, a die slot coating method, a bar coating method and a molding coating method, for example, as a method of coating the polymer layer 300. [ Coating may be used to coat the polymer layer 300 on the sacrificial layer 200 deposited along the master mold form.

By controlling the thickness of the polymer layer 300 coated through the third step S300, the thickness of the polyimide polyimide film PI can be controlled.

Specifically, the thickness of the polymer layer 300 may be increased by coating the polymer layer 300 in multiple layers, or a solvent may be added to improve the viscosity to increase the thickness. On the contrary, it is also easy to control the thickness of the polymer layer 300 to be low.

In the fourth step S400, the sacrificial layer 200 and the substrate 100 under the polymer layer 300 may be etched by surface cleaning, as shown in FIG. 2D. Through this, a nanopattern having a large aspect ratio is formed, so that a polyimide film (PI) having super-hydrophobicity and super-water repellency, which is one feature of the present invention, is formed.

The fourth step S400 may be performed by using any one of hydrofluoric acid (HF), buffered oxide etchant (BOE), and phosphoric acid solution to remove the sacrificial layer 200 and the substrate 100 can be etched.

The fifth step S500 is a process of removing the sacrificial layer 200 and the polymer layer 300 on which the substrate 100 is etched by the surface cleaning of the fourth step S400 as shown in FIG. The atomic layer deposition method may be used once again to coat the atomic layer 400. This improves the resistance of the polymer layer 300 to water vapor or oxygen in a gaseous state, and finally forms a polyimide film having super-hydrophobicity, super water repellency and impermeability at the same time.

In the fifth step S500, an ALD layer, which is an atomic layer 400, is deposited on the surface of the polymer layer 300 by plasma-enhanced atomic layer deposition or thermal ALD by atomic layer deposition, as shown in FIG. 2 (e) Can be coated.

The thickness of the ALD layer, which is the atomic layer 400, is preferably equal to or less than a preset threshold value, and a preset threshold value is sufficient to block water vapor and oxygen in a gaseous state and maintain flexibility.

Through the respective steps of the method of producing a polyimide film having the impermeability and superhydrophobicity of the present invention, the polyimide film having the impermeable and superhydrophobic properties, as shown in Figs. 3 and 4, The aspect ratio a: b of one nanometer pattern is as large as 1: 5 or more (preferably, 1:10 or more), and the contact angle θ is 150 ° or more, preferably 170 ° Or more.

In addition, the hysteresis of the sliding angle is less than 10 ㅀ, which is a polymer film that has super-hydrophobicity and super water repellency as well as impermeability due to the ALD layer, which is an atomic layer coated on the surface.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

100: substrate
200: sacrificial layer
300: polymer layer
400: atomic layer

Claims

A first step S100 of processing a master mold of a nano pattern according to a predetermined size on the substrate 100;
A second step (S200) of depositing a sacrificial layer (200) on the master mold processed by the first step (S100) through atomic layer deposition (ALD);
A third step (S300) of coating the polymer layer (300) on the sacrificial layer (200) deposited by the second step (S200);
A fourth step (S400) of etching the sacrificial layer 200 and the substrate 100 under the polymer layer 300; And
A fifth step (S500) of coating the surface of the polymer layer 300 on which the sacrificial layer 200 and the substrate 100 are etched by the atomic layer deposition method, by the fourth step S400;
Wherein the polyimide film has an impermeability and a superhydrophobicity.

The method according to claim 1,
In the first step S100,
A master mold of a nano pattern having an aspect ratio of 1: 5 or more is processed on the substrate 100 by using a femtosecond laser or fine processing using DRIE (Deep Reactive Ion Etching) By weight based on the total weight of the polyimide film.

The method according to claim 1,
In the second step S200,
At least one of SiO ₂ , SiN x, and Al ₂ O ₃ is used as the sacrifice layer 200,
Characterized in that the sacrificial layer (200) is deposited by plasma-enhanced atomic layer deposition (Plasma-Enhanced ALD) using atomic layer deposition or thermal ALD.

The method according to claim 1,
In the third step S300,
As the polymer layer 300, polyimide is used,
Characterized in that the polymer layer (300) is coated by any one of spin coating, slot coating, bar coating and molding coating.

The method according to claim 1,
In the fourth step S400,
The sacrifice layer 200 and the substrate 100 under the polymer layer 300 may be formed using any one of HF (Hydrofluoric acid), Buffered Oxide Etchant (BOE), and Phosphoric Acid solution. Wherein the polyimide film is a polyimide film.

The method according to claim 1,
In the fifth step S500,
Characterized in that the atomic layer (400) is deposited by plasma-enhanced atomic layer deposition (Plasma-Enhanced ALD) using atomic layer deposition or thermal ALD.

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