KR101617611B1 - Method for forming superhydrophilic metallic surface - Google Patents

Abstract

(A) immersing and holding a metal substrate in an acidic solution; (b) immersing the metal substrate in hot water to maintain it; And (c) treating the surface of the metal substrate with an air plasma. The method for forming a superhydrophilic metal surface according to the present invention comprises the steps of: (a) It is possible to simplify the manufacturing process and reduce the manufacturing cost, and it is possible to easily surface-modify the surface of the metal base material having a large / large-area or three-dimensional surface by superhydrophilic property, . In addition, the metal substrate surface-treated by the present invention is capable of permanently retaining an extremely hydrophilic surface having a contact angle of 10 ㅀ or less by simultaneously providing microscale fine concavo-convex structure and nanoscale fine pores, The electronic devices and machinery involved can be usefully used in transportation vehicles, aircraft, railways, ships or domestic / industrial refrigeration and air conditioning systems and consumer electronics.

Description

TECHNICAL FIELD The present invention relates to a method for forming a superhydrophilic metallic surface,

The present invention relates to a method for forming a superhydrophilic metal surface, and more particularly, to a method for forming a superhydrophilic surface through a texturing treatment of a metal surface.

In general, the surface of the metal substrate has a unique surface energy. This surface energy appears as the contact angle of the liquid to the metal substrate when any liquid contacts the metal substrate.

The contact angle is the angle formed by the free surface of the liquid with the solid plane when the liquid is in contact with the solid, and is determined by the cohesive force between the liquid molecules and the adhesion force between the liquid and the solid. The solid plane when the contact angle of the liquid with the solid plane exceeds 90 ° is the hydrophobicity which has a low affinity with water and the solid plane when the contact angle of the liquid with the solid plane is less than 90 ° It is hydrophilicity, which is a property of affinity with water.

The value of the inherent contact angle of the surface of the metal base can be changed through the surface processing. In other words, the hydrophilic surface having a contact angle of less than 90 deg. Can be further reduced in contact angle through the surface processing treatment. Especially, when the contact angle is 10 deg. Or less and the affinity with water is extremely high, it is called superhydrophilic. Hydrophilicity has been studied to prevent contamination and self-cleaning of optical parts and surfaces that require anti-fog [Non-patent documents 0001 and 0002], the fin of a heat exchanger The efficiency of the heat exchanger can be increased by improving the flow of the condensed water generated on the surface of the fin.

This superhydrophilic metal surface is fabricated by controlling the surface energy and surface structure. Aluminum, which is widely used in various fields, is realized by chemical etching, sol-gel method, surface coating method, anion exchange method, etc. [Non-Patent Document 0003]. However, it has been pointed out that the conventional superhydrophilic surface fabrication has a limit in that the processing method is complicated, the surface area that can be manufactured is limited, and that processing is possible only on a flat surface.

 X. J. Feng, L. Jiang, "Design and Creation of Superwetting / Antiwetting Surfaces," Adv. Mater., Vol. 18, 3063, 2006.  X. M. Li, D. Reinhoudt, M.C. Calama, "What do we need for a superhydrophobic surface? A review on the recent progress in the preparation of superhydrophobic surfaces," Chem. Soc. Rev., vol.36, 1350, 2007.  Yanhui Che, Yanhua Liu, "Fabrication of superhydrophobic aluminum alloy surface with excellent corrosion resistance by a facile and environment-friendly method." Applied Surface Science. vol.283, 367, 2013.

SUMMARY OF THE INVENTION The present invention has been made to overcome the problems of the prior art as described above, and it is an object of the present invention to provide a superhydrophilic metal surface Lt; / RTI >

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including: (a) immersing and holding a metal substrate in an acidic solution; (b) immersing the metal substrate in hot water to maintain it; And (c) treating the surface of the metal substrate with an air plasma.

The present invention also proposes a metal substrate having an superhydrophilic surface formed by the above method.

Further, the present invention proposes a fin for a heat exchanger comprising a metal base having the superhydrophilic surface.

The method of forming a superhydrophilic metal surface according to the present invention can simplify the manufacturing process and reduce the manufacturing cost by performing etching and hydrothermal treatment using an acid solution, and can be used for a large-scale / large-area or three- The surface modification treatment can be performed with super hydrophilicity, and the effect of superhydrophilic treatment can be sustained for a long time. In addition, the metal substrate surface-treated by the present invention can maintain an extremely hydrophilic surface having a contact angle of 10 deg. Or less by providing microscale micro concavo-convex structure and nanoscale micropores at the same time, The electronic devices and machinery involved can be usefully used in transportation vehicles, aircraft, railways, ships or domestic / industrial refrigeration and air conditioning systems and consumer electronics.

1 is a flow chart of a method of forming a superhydrophilic metal surface according to the present invention.
2 is a schematic view showing each step of the method of forming a superhydrophilic metal surface according to the present embodiment.
3 is a scanning electron microscope (SEM) photograph of the aluminum sample surface prepared in Comparative Example 2, Comparative Example 3 and Example.
Fig. 4 shows the results of measurement of the water cotact angle over time of the sample surface prepared in Examples and Comparative Examples 1 to 3. Fig.
5 (a) to 5 (d) are photographs showing the water contact angles at the surface of each sample after 8 weeks from the start of measurement of the water contact angle on the sample surface prepared in Examples and Comparative Examples 1 to 3 .
FIG. 6 is a graph showing the results of comparison between the samples before the air-plasma treatment (Examples: 'Micro / Nano', Comparative Example 1: 'Bare', Comparative Example 2: Micro (Etching) , And Comparative Example 3: 'Nano (boiling)') was measured over time.
7 (a) to 7 (d) are graphs showing the results of measurement of the water contact angle for each of the samples before the air-plasma treatment in Examples and Comparative Examples 1 to 3 Of water contact angle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Embodiments in accordance with the concepts of the present invention can make various changes and have various forms, so that specific embodiments are illustrated in the drawings and described in detail in this specification or application. It should be understood, however, that it is not intended to limit the embodiments according to the concepts of the present invention to the particular forms of disclosure, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ",or" having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Hereinafter, a method of forming a superhydrophilic metal surface according to the present invention will be described in detail.

As shown in FIG. 1, the method for forming a superhydrophilic metal surface according to the present invention comprises the steps of: (a) immersing and holding a metal substrate in an acidic solution; (b) immersing the metal substrate in hot water to maintain it; And (c) treating the metal substrate surface with an air plasma, each of which will be described in detail below.

In the step (a), the metal substrate is immersed in an acidic solution and held to form a microscale irregular structure on the surface of the metal substrate.

At this time, the material of the metal base material is not particularly limited, and can be applied to any of pure metals or alloys.

The acid solution may vary in kind depending on the metal substrate. For example, an aqueous solution of hydrochloric acid, an aqueous solution of sulfuric acid, an aqueous solution of nitric acid, and a solution of water of aqua regia may be used, but the present invention is not limited thereto.

On the other hand, it is preferable that the irregularities having micro-scale formed in this step have a diameter of 1 to 3 탆. If the diameter of the irregularities is less than 1 탆, the surface roughness is too low, Mu] m, the etching time must be very short, so that there is a problem that the surface is not uniform.

Next, in the step (b), a metal substrate having microscopic irregularities on its surface is immersed in hot water and held.

The surface of the metal substrate in the hot water is activated to form nanoscale micropores. In addition, the metal cation generated from the metal substrate and the oxygen anion derived from the hot water react with each other to form a metal oxide, Further improve.

At this time, the hot water is preferably 90 ° C or higher, more preferably 100 ° C boiling water (atmospheric pressure).

On the other hand, the pores having nanoscale formed in this step preferably have a diameter of 100 to 200 nm.

Finally, in step (c), the surface of the metal substrate is treated with an air plasma to further improve hydrophilicity.

Since the air plasma treatment performed in this step is plasma treatment in an atmospheric pressure, room temperature, and air atmosphere unlike the conventional plasma treatment, the vacuum process or the preheating process is not required at all, A hydrophilic film is formed on the surface of the substrate.

Here, the atmospheric pressure means a pressure near atmospheric pressure or atmospheric pressure. The plasma generated by the atmospheric pressure is a glow discharge type having a comparatively low energy, and the surface reforming effect to the hydrophilic property Lt; / RTI >

As described above, in the present invention, by performing the steps (a) and (b), hydrophilic properties can be maximized by forming a hierarchical surface curved structure of micro / nanocomposite structure through a simple process and further, have. In addition, through step (c), an increase in surface energy is induced on the surface of the metal substrate to further improve the hydrophilicity, thereby achieving superhydrophilic property.

The method of forming a superhydrophilic metal surface according to the present invention can simplify a manufacturing process and reduce manufacturing cost by performing etching and hydrothermal treatment using an acid solution, The surface modification treatment can be easily performed with superhydrophilic property, and the effect of superhydrophilic treatment can be sustained for a long time. In addition, the metal substrate surface-treated by the present invention is capable of permanently retaining an extremely hydrophilic surface having a contact angle of 10 ㅀ or less by simultaneously providing microscale fine concavo-convex structures and nanoscale fine pores, The electronic devices and machinery involved can be usefully used in transportation vehicles, aircraft, railways, ships or domestic / industrial refrigeration and air conditioning systems and consumer electronics.

Hereinafter, the present invention will be described in more detail based on examples. However, the examples given below are illustrative and not intended to limit the scope of the present invention.

<Examples>

As shown in FIG. 2, an aluminum sample prepared by washing with acetone, ethanol and DI water for 3 minutes was etched for 3 minutes with a mixed solution of diluted hydrochloric acid (water: hydrochloric acid = 2: 1) Microstructures were formed on the surface of the sample and then immersed in boiling water for 15 minutes to form additional nanostructures on the surface. Then, an aluminum sample having a micro / nanocomposite structure surface (MN-surface) was obtained by air-plasma treatment (250 W, 30 minutes) of the aluminum sample surface on which the micro / nano structure was formed.

&Lt; Comparative Example 1 &

The sample was ultrasonically washed with acetone, ethanol and DI water for 3 minutes, and then subjected to an air-plasma treatment (250 W, 30 minutes) to prepare a bare aluminum plate.

&Lt; Comparative Example 2 &

Ultrasonic cleaning was performed with acetone, ethanol and DI water for 3 minutes each, and the aluminum sample was etched with a mixed solution of diluted hydrochloric acid (water: hydrochloric acid = 2: 1) for 3 minutes to form microstructures on the sample surface , An aluminum sample having a microstructure surface (M-surface) was obtained by air-plasma treatment (250 W, 30 minutes) of the sample surface.

&Lt; Comparative Example 3 &

The sample was ultrasonically cleaned with acetone, ethanol, and DI water for 3 minutes each, and the aluminum sample thus prepared was immersed in boiling water for 15 minutes to form a nanostructure on the surface, (250 W, 30 minutes) to obtain an aluminum sample having a nanostructure surface (N-surface).

<Experimental Example>

In order to confirm the degree of hydrophilicity according to the difference in structure of the aluminum sample surface according to Examples and Comparative Examples 1 to 3, the microstructure of the surface of the sample prepared in Examples and Comparative Examples was observed, and the number The change in the water cotact angle over time was measured.

3 (a) to 3 (c) are scanning electron microscope (SEM) photographs of the aluminum sample surface obtained in Comparative Example 2, Comparative Example 3 and Example, respectively, and the specimen prepared in Comparative Example 2 was subjected to hydrochloric acid etching 3 (a)). On the aluminum surface, a rectangular structure having a size of 2 to 4 탆 was formed to form a micro texture (see Fig. 3 (a)) and the specimen prepared in Comparative Example 3 reacted with aluminum in boiling water (Fig. 3 (b)). On the other hand, it was confirmed that the specimens prepared in the examples had a complex structure in which micro and nanotextures were mixed (see Fig. 3 (b)).

FIG. 4 is a graph showing the results of measurement of the water cotact angle over time at the sample surface prepared in Examples and Comparative Examples 1 to 3. As shown in FIG. 4, the surface of the aluminum sample prepared in the Example was The contact angle was maintained close to 0 ° until the elapse of 8 weeks from the measurement point. In the case of the samples prepared in Comparative Examples 2 and 3, the contact angle was constant during one week after the start of measurement, but the contact angle was maintained after 2 weeks or 4 weeks And the hydrophilicity is decreased.

FIG. 5 is a photograph showing the water contact angle at each sample surface at the end of 8 weeks after the start of the water contact angle measurement. Referring to FIG. 5, the surface of the aluminum sample prepared in the example has a contact angle close to 0 ° While the samples prepared in Comparative Examples 1 to 3 showed a contact angle of at least 20 °.

6 is a graph showing the results of comparison between the samples before the air-plasma treatment (Examples: 'Micro / Nano', Comparative Example 1: 'Bare', Comparative Example 2: Micro Etching) ', and Comparative Example 3:' Nano (boiling) ') as a result of measuring the water cotact angle over time. As compared with FIG. 4, However, when the air-plasma surface treatment is performed, the increase in the contact angle is further delayed, and it can be confirmed that the hydrophilicity can be maintained relatively good even if the time elapses.

7 is a photograph showing the water contact angles at the surface of each sample after 8 weeks from the start of the water contact angle measurement on samples before air-plasma treatment in Examples and Comparative Examples 1 to 3, Comparing this with FIG. 5, it can be seen that the air-plasma surface treatment exhibits improved hydrophilicity even after prolonged elapse of time in all samples.

Claims (9)

(a) immersing and holding a metal substrate in an acidic solution to form micro scale irregularities on the surface of the metal substrate;
(b) immersing and holding the metal substrate in hot water to form nanoscale pores on the surface of the metal substrate; And
(c) treating the surface of the metal substrate with an air plasma to induce an increase in surface energy on the surface of the metal substrate to improve hydrophilicity. The method according to claim 1,
Wherein the metal substrate is aluminum. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
Wherein the acid solution in step (a) is an aqueous solution of hydrochloric acid, an aqueous solution of sulfuric acid, an aqueous solution of nitric acid, or an aqueous solution of aqua regia. The method according to claim 1,
Wherein a micro scale irregularity having a diameter of 1 to 3 占 퐉 is formed on the surface of the metal base in the step (a). The method according to claim 1,
Wherein the hot water in step (b) is boiling water. The method according to claim 1,
Wherein nanoscale pores having a diameter of 100 to 200 nm are formed on the surface of the metal substrate in the step (b). A metal substrate having a superhydrophilic surface formed by the method according to any one of claims 1 to 6. 8. The method of claim 7,
And a micro / nano composite structure having a superficial surface curvature structure. A fin for a heat exchanger comprising the metal base according to claim 8.

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