KR102754968B1 - Development of Super Water-repellent (Super Oil-repellent) Aluminum 3000 Series Alloy Surface using Nanostructures - Google Patents

Abstract

The present invention relates to the development of a superhydrophobic (superoil-repellent) aluminum 3000 series alloy surface using nanostructures. The method for producing an oil-repellent and water-repellent film on the surface of a 3000 series aluminum alloy according to the present invention can impart water-repellent and oil-repellent properties by using a cross-linked PDMS derivative represented by the chemical formula 1 and an organic solvent at a specific mixing ratio, has a low manufacturing cost, and can control the thickness of the coating film to several to several tens of nm, so that it can be applied to coating of a microstructured oxide film. Therefore, it can be useful for vapor recovery devices/equipment, pipes, hoods, hood parts, nozzles, ducts, etc. that require water-repellent and oil-repellent properties.

Description

{Development of Super Water-repellent (Super Oil-repellent) Aluminum 3000 Series Alloy Surface using Nanostructures}

The present invention relates to the development of a superhydrophobic (superoleophobic) aluminum 3000 series alloy surface using nanostructures.

In general, hydrophobicity and oleophobicity refer to the properties of being difficult to get wet with water and oil, respectively, and superhydrophobicity/superoleophobicity are generally defined in the relevant fields as a case where the contact angle for water on the surface of a solid is 150° or higher, and the contact angle for oil is 150° or higher.

Recently, superhydrophobic surfaces with a water contact angle of more than 150° have attracted considerable attention because of their importance in both fundamental research and practical applications. Superhydrophobicity and superoleophobicity refer to the physical properties of surfaces of objects that make them extremely difficult to wet with water and oil, respectively. For example, plant leaves, insect wings, and bird wings have the property that any external contaminants can be removed without any special removal process or that they do not become contaminated in the first place. This is because plant leaves, insect wings, and bird wings have superhydrophobicity.

Wettability is a key surface property of solid materials, which is largely governed by both chemical composition and geometric micro/nanostructure. Wettable surfaces have attracted much attention due to their potential applications in various fields such as oil-water separation, antireflection, anti-bioadhesion, anti-sticking, anti-fouling, self-cleaning, and fluid turbulence suppression.

Meanwhile, although there have been several reports on the production of superhydrophobic aluminum, superhydrophobicity/superoleophobicity on metal substrates has received relatively little attention.

Recently, as air pollution has become more serious due to environmental pollution, and the occurrence of yellow dust and fine dust has increased, it is common to operate a ventilation system to purify indoor air rather than opening windows to ventilate. In addition, ventilation systems are constantly operated to remove household dust, food odors, cigarette odors, various harmful odors generated during work, harmful air such as carbon monoxide, fine dust, and oil vapor generated in residential facilities, business facilities, and commercial facilities such as homes, workplaces, industrial sites, restaurants, offices, and restrooms or bathrooms.

These ventilation devices are usually implemented by complex facilities such as ventilation systems that are systematized and installed in specific locations and automatically operate depending on the level of indoor pollution, or by window-type ventilation fans that are installed on walls adjacent to the exterior and simply circulate the air inside and outside.

However, these ventilators inevitably accumulate dust inside and outside the ventilator when used for a certain period of time, which is unsanitary and requires the troublesome task of disassembling and cleaning the ventilator to remove the dust.

In particular, ventilation fans installed in restaurants or other places where oily vapor is generated do not have any filtering devices to primarily absorb oil or fine dust, so when used for a long period of time, oil and fine dust may combine and flow downward, which not only poses serious concerns for hygiene but also poses the risk of fire.

Publication of Patent Publication No. 10-2014-0101193

The purpose of the present invention is to provide a method for producing an oil-repellent and water-repellent film on a 3000 series aluminum alloy.

Another object of the present invention is to provide a 3000 series aluminum alloy having an oil-repellent and water-repellent film formed by the above-mentioned manufacturing method.

Another object of the present invention is to provide a method for manufacturing an anodic oxide film in the form of pillar-on-pores on the surface of a 3000 series aluminum alloy.

Another object of the present invention is to provide a 3000 series aluminum alloy having a pillar-on-pore type anodic oxide film formed by the above-mentioned manufacturing method.

To achieve the above purpose,

The present invention comprises a pre-patterning step (step 1) of first anodizing a 3000 series aluminum alloy at 30-50 V for 5-15 hours, and then removing the first anodized film by etching;

Secondary anodizing step (step 2) at 35-45 V for 1-10 minutes;

Step 3: pore widening treatment by immersing in a 0.05-1.0 M phosphoric acid (H ₃ PO ₄ ) solution for 10-60 minutes;

Step 4 of the third anodizing treatment at 35-45 V for 1-10 minutes; and

A step (step 5) of coating with a coating composition comprising a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the following chemical formula 1 and an organic solvent;

A method for producing an oil-repellent and water-repellent film on a 3000 series aluminum alloy is provided.

[Chemical Formula 1]

(In the above chemical formula 1, x and y are each an integer from 1 to 30.)

In the manufacturing method according to the present invention, step 1 is a pre-patterning process in which a 3000 series aluminum alloy is anodized and then etched to remove the anodized film, thereby leaving a microstructure pattern on the surface of the 3000 series aluminum alloy. An anodized film formed by a post-process anodizing process can be uniformly formed along the microstructure pattern of the metal substrate surface formed by the pre-patterning process.

In the manufacturing method according to the present invention, steps 2 to 4 are manufacturing steps for forming an anodized film having a pillar-on-pore (POP) structure on the surface of a 3000 series aluminum alloy through anodizing treatment and pore expansion treatment. Here, the anodized film exhibits hydrophilicity, and the anodized film having a POP structure according to the present invention exhibits superhydrophilicity. Here, the coating composition according to step 5 is for imparting oil-repellent and water-repellent properties, and is technically characterized in that the micro-nano surface structure of the anodized film is maintained by thinly coating the micro-nano surface of the POP structure at the level of a monomolecular layer thickness, thereby maximizing the oil-repellent and water-repellent effects.

The above 3000 series aluminum alloys can include Al 3003, Al 3004, Al 3005, Al 3015, Al 3103, Al 3104, Al 3105, etc.

The anodic oxide film exhibits hydrophilicity, and in one embodiment of the present invention, the anodic oxide film having a pillar-on-pore type microstructure in which pillars are formed on the pore structure according to steps 1 to 4 can exhibit superhydrophilicity with a contact angle of 10° or less.

Preferably,

Step 2: Secondary anodizing of a pre-patterned 3000 series aluminum alloy at 38-42 V for 3-7 minutes;

Step 3: immersing in a 0.05-0.15 M phosphoric acid (H ₃ PO ₄ ) solution for 30-45 minutes to perform pore widening treatment; and

It may include a step (step 4) of third anodizing treatment for 3-7 minutes at 38-42 V;

More preferably,

Secondary anodizing step (step 2) for 3-5 minutes at 39-41 V;

Step 3: immersing in a 0.06-0.14 M phosphoric acid (H ₃ PO ₄ ) solution for 33-42 minutes to perform pore widening treatment; and

It may include a step (step 4) of third anodizing treatment at 39-41 V for 3-5 minutes.

Especially preferably,

Secondary anodizing step (step 2) at 39.5-40.5 V for 3.8-4.2 minutes;

Step 3: immersing in a 0.095-0.105 M phosphoric acid (H ₃ PO ₄ ) solution for 34-41 minutes to perform pore widening treatment; and

It may include a step (step 4) of third anodizing treatment at 39.5-40.5 V for 3.8-4.2 minutes.

If the processing conditions of steps 2 to 4 described above are exceeded, problems such as a uniform anodic oxide film not being formed or superhydrophilicity not being achieved may occur.

The anodizing process may be performed by placing a 3000 series aluminum alloy to be anodized as a working electrode and an anode in an oxidation treatment reaction tank containing an electrolyte at -5 to 30°C, and then placing a platinum (Pt) or carbon electrode as a counter electrode and a cathode to oxidize the alloy. The distance between the working electrode and the counter electrode may be 1-15 cm, preferably 3-12 cm, more preferably 4-10 cm, still more preferably 4.5-8 cm, and particularly preferably 4.75-5.25 cm.

The electrolyte for the first and second anodic oxidation treatments may be sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), oxalic acid (C ₂ H2O ₄ ), chromic acid, hydrofluoric acid, dipotassium phosphate (K ₂ HPO ₄ ), etc., either singly or in a mixture of two or more.

Preferably, the electrolyte may use 0.1-0.5 M oxalic acid at -5 to 25°C, more preferably 0.27-0.33 M oxalic acid at 15 to 25°C, and particularly preferably 0.285-0.315 M oxalic acid at 19 to 21°C.

In the coating composition used in the above step 5, the organic solvent may be pentane, hexane, heptane, octane, etc., used alone or in a mixture of two or more, and in the present invention, hexane was used as an example.

Preferably,

The coating composition used in the above step 5 is

Based on 10 parts by weight of organic solvent,

It may contain 0.01-10 parts by weight of a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 above.

More preferably,

The coating composition used in the above step 5 is

Based on 10 parts by weight of organic solvent,

It may contain 0.04-5 parts by weight of a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 above.

Even more preferably,

The coating composition used in the above step 5 is

Based on 10 parts by weight of organic solvent,

It may contain 0.04-2 parts by weight of a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 above.

Especially preferably,

The coating composition used in the above step 5 is

Based on 10 parts by weight of organic solvent,

It may contain 0.04-1 part by weight of a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 above.

Most preferably,

The coating composition used in step 5 above is

Based on 10 parts by weight of organic solvent,

It may contain 0.05-0.17 parts by weight of a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 above.

If the content of the cross-linked PDMS derivative represented by the chemical formula 1 is outside the above range, there may be a problem of reduced oil repellency and water repellency, or insufficient uniformity of the coating.

The coating composition according to the present invention is characterized in that it does not contain a PDMS (Polydimethylsiloxane) derivative represented by the following chemical formula 2.

[Chemical formula 2]

(In the above chemical formula 2, m is an integer from 1 to 100, preferably an integer from 1 to 80, and more preferably an integer from 1 to 60.)

The above coating composition can be used by methods such as drop coating, dip coating, and spin coating, but is not limited thereto.

In addition, the present invention provides a 3000 series aluminum alloy having an oil-repellent and water-repellent film formed by the above-mentioned manufacturing method.

Furthermore, the present invention comprises a pre-patterning step (step 1) of first anodizing a 3000 series aluminum alloy at 30-50 V for 5-15 hours, and then removing the first anodized film by etching;

Secondary anodizing step (step 2) at 35-45 V for 1-10 minutes;

Step 3: immersing in a 0.05-1.0 M phosphoric acid (H ₃ PO ₄ ) solution for 10-60 minutes to perform pore widening treatment; and

Step 4 (third anodizing process) for 1-10 minutes at 35-45 V; including;

A method for manufacturing a pillar-on-pore type anodic oxide film on the surface of a 3000 series aluminum alloy is provided.

The above pillar-on-pore type anodized film is characterized by having pillars formed on a pore structure, and the above anodized film is characterized by being superhydrophilic.

In addition, the present invention provides a 3000 series aluminum alloy having a pillar-on-pore type anodic oxide film formed by the above manufacturing method.

The method for producing a superhydrophilic anodized film on a 3000 series aluminum alloy according to the present invention can produce a uniform anodized film, and can impart superhydrophobicity and superoleophobicity to the anodized film according to a coating composition using a cross-linked PDMS derivative represented by chemical formula 1 and an organic solvent at a specific mixing ratio, and the coating composition has a low manufacturing cost and can control the coating film thickness to several to several tens of nm, so that it can also be applied to coating of a microstructured oxide film.

Figure 1 is an image of the top view, cross view, and tilted view of a specimen that was processed through all of Examples 1-1 to 1-2 up to the third anodic oxidation (step 4), taken using a field emission scanning electron microscope (FE-SEM).

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only intended to illustrate the present invention, and the content of the present invention is not limited to the following examples.

<Manufacturing Example> Manufacturing of Pillar-On-Pore (POP) Structured Anodized Film through Anodizing of Aluminum 3003 Alloy

In order to determine the anodizing treatment conditions for forming a POP structured anodizing film on the surface of aluminum 3003 alloy, the following procedure was performed.

To manufacture an aluminum alloy anodized film, pre-patterning, pore widening (PW), and voltage modulation were performed using aluminum 3003 alloy.

The composition information of the above aluminum 3003 alloy (Al 3003, size 20×30mm, manufacturer: Alcoa INC, USA) is as follows.

Preparation stage: Electrochemical polishing process

To remove impurities on the surface of the above aluminum 3003 alloy, it was washed by ultrasonic treatment in acetone at 20°C for 10 minutes and in ethanol for 10 minutes.

Next, to obtain surface roughness, the ultrasonically cleaned aluminum 3003 alloy was placed in a mixed solution of ethanol and perchloric acid (Junsei, HClO ₄ :C ₂ H ₅ OH = 4:1 (v/v)) and electrochemically polished for 1 minute at room temperature (20°C) with a voltage of 20 V. The aluminum alloy surface after electrochemical polishing was confirmed to have a good reflection and a flat surface.

Step 1: Pre-patterning process through primary anodization and chemical etching

The above-mentioned electropolished aluminum 3003 alloy (1 mm thick, 20×30 mm in size) was used as a working electrode and a platinum (Pt) electrode as a cathode, and the two electrodes were kept at a constant distance of 5 cm to perform the first anodic oxidation. The first anodic oxidation was performed using 0.3 M oxalic acid as an electrolyte and keeping the electrolyte temperature at a constant 0℃ using a double beaker. In order to suppress the disturbance of stable oxide growth due to local temperature increase, stirring was performed at a constant speed, and a voltage of 40 V was applied using a constant voltage method to perform the first anodic oxidation process for 6 hours to grow an alumina layer.

The alumina layer grown through the first anodic oxidation treatment was subjected to a pre-patterning process to remove the grown alumina layer by etching it by immersing it in a solution containing a mixture of chromic acid (1.8 wt%) and phosphoric acid (6 wt%) at 65°C for 10 hours.

Step 2: Secondary anodization

The above pre-patterned aluminum 3003 alloy (1 mm thick, 20×30 mm in size) was used as a working electrode and a platinum (Pt) electrode as a cathode, and the two electrodes were kept at a constant distance of 5 cm to perform secondary anodization. The secondary anodization was performed using 0.3 M oxalic acid as an electrolyte and keeping the electrolyte temperature at a constant 20°C using a double beaker. In order to suppress the disturbance of stable oxide growth due to local temperature increase, stirring was performed at a constant speed, and the secondary anodization process was performed by applying a voltage of 40 V for 1-10 minutes using a constant voltage method to grow an alumina layer.

Step 3: Pore widening (PW)

The alumina layer grown through secondary anodic oxidation was subjected to a pore widening (PW) process by immersing it in a 0.1 M phosphoric acid solution at 30°C for 10 to 60 minutes before performing the tertiary anodic oxidation.

Step 4: 3rd anodization

The third anodizing process was performed in the same manner as the above second anodizing, but the voltage application time was fixed to 4 minutes, to further grow the alumina layer.

The above secondary anodizing (step 2), pore expansion (step 3), and tertiary anodizing (step 4) processes were performed under the conditions shown in Table 1 below to produce a microstructured anodizing film on the surface of an aluminum 3003 alloy.

Secondary anodic oxidation
(Step 2) Pore expansion
(Step 3) 3rd anodization
(Step 4) Voltage (V) Time (min) Time (min) Voltage (V) Time (min) Example 1-1 40 4 35 40 4 Example 1-2 40

<Experimental Example 1> Microstructural Analysis of the Anodized Film

The surfaces (top view), cross-sections, and tilted views of the specimens treated with the third anodic oxidation (step 4) in Examples 1-1 to 1-2 of Table 1 above were observed using a field emission scanning electron microscope (FE-SEM) system (AURIGA® small dual-bean FIB-SEM, Zeiss).

Figure 1 is an image of the top view, cross view, and tilted view of a specimen that was processed through all of Examples 1-1 to 1-2 up to the third anodic oxidation (step 4), taken using a field emission scanning electron microscope (FE-SEM).

As shown in Fig. 1, the smooth lower part in the cross-view image of the specimen treated with pore expansion for 35 min is aluminum 3003 alloy, the thickness of the pore-shaped columnar layer below shows a porous columnar shape as a film due to the third anodic oxidation, and the upper part shows a pillar shape as a film due to the second anodic oxidation and pore expansion treatment. It seems that the POP microstructure is well shown in the specimen treated with pore expansion for 35-40 min (especially 40 min).

From the results of Experimental Example 1, it is determined that it is desirable to perform the second anodizing condition at an applied voltage of 40 V for 4 minutes, pore expansion for 35-40 minutes, and the third anodizing condition at an applied voltage of 40 V for 4 minutes.

<Experimental Example 2> Evaluation of coating composition for imparting superhydrophobic and superoil-repellent functions

The coating compositions to be used to impart superhydrophobic and superoil-repellent functions to the specimens of Examples 1-1 and 1-2 above were evaluated.

Specifically, the metal substrate was prepared by subjecting aluminum 3003 alloy to only the electrolytic polishing process described in the examples. In other words, no anodic oxidation treatment was performed.

SYLGARD 184 Silicon Elastomer Curing Agent, a cross-linked PDMS derivative represented by the chemical formula 1 (manufactured by Dow Chemical Company), SYLGARD 184 Silicon Elastomer Base, a PDMS derivative represented by the chemical formula 2 (manufactured by Dow Chemical Company), and/or hexane were dropped at 60 μL per 2.5 cm × 3 cm of the substrate area as a coating agent, and then coated by spin coating. The spin coating condition was 1000 rpm for 30 seconds. In addition, drop coating was performed as another coating method. In the case of drop coating, an appropriate amount of the coating agent was dropped, and the substrate was tilted from side to side several times for coating.

Manufacturing examples 2-1 to 2-4 used a mixture of hexane, a main agent (chemical formula 2), and a curing agent (chemical formula 1) as a coating agent.

Manufacturing examples 2-5 to 2-10 used a mixture of hexane and a curing agent (chemical formula 1) as a coating agent.

Next, the coated substrate was heat treated in an oven at 300°C for 30 minutes to complete curing.

For reference, the coating compositions of Manufacturing Examples 2-1 to 2-10 below are compositions used in the inventor's prior application (Application No. 10-2021-0085454).

Manufacturing example Coating composition (weight ratio) coating
method Coating liquid
amount used
(μL/7.5cm ² ) Hexane Coating agent
(SYLGARD 184) Base
(subject) Curing agent
(hardener) 2-1 10 1 0.1 drop 65 2-2 10 1 0.1 spin 65 2-3 10 2 0.2 drop 65 2-4 10 2 0.2 spin 65 2-5 10 0 1 drop 65 2-6 10 0 1 spin 65 2-7 10 0 1 spin 65 2-8 10 0 1 drop 85 2-9 10 0 0.5 drop 85 2-10 10 0 0.1 drop 85

[Chemical Formula 1: Curing agent]

In the above chemical formula 1, x and y are each an integer from 1 to 30.

[Chemical Formula 2: Base]

In the above chemical formula 2, m is an integer from 1 to 100.

For the specimens of the above manufacturing examples 2-1 to 2-10, water (purified water) and oil (edible oil) were dropped respectively to evaluate the contact angle and contact history angle, and the results are shown in Table 3 below.

Here, the 'contact angle hysteresis' is measured by placing a sample on a stage of a device whose inclination can be finely adjusted, dropping water or oil on the sample, slowly adding an inclination to the stage, and then measuring the inclination angle at which the water or oil begins to flow out. In other words, the lower the contact hysteresis angle, the better the water/oil repellency. For example, if the contact hysteresis angle is 1°, water or oil flows out even if the sample is tilted by just 1°, and if the contact hysteresis angle is 90°, water or oil does not flow out even if the sample is tilted at 90°.

Table 3 below shows the results of evaluating water and oil repellency after coating a coating solution according to Manufacturing Examples 2-1 to 2-10 on a non-anodized sample of an aluminum 3003 alloy substrate on which a microstructured oxide film has not been formed on the surface.

Non -anodized substrate water Oil Contact angle (0 sec) Contact history angle Contact angle (60 seconds) Contact history angle Manufacturing Example 2-1 107.59±1.31° 29.11±0.44° 60.56±0.43° 25.74±0.41° Manufacturing Example 2-2 104.57±0.35° 25.65±0.58° 61.05±0.67° 26.95±0.64° Manufacturing Example 2-3 99.57±0.22° 27.43±0.75° 57.05±1.05° 27.56±0.37° Manufacturing Example 2-4 100.28±1.24° 27.91±0.94° 54.87±1.44° 27.79±0.09° Manufacturing Example 2-5 102.66±0.80° 22.20±0.58° 60.79±1.38° 22.12±0.37° Manufacturing Example 2-6 100.87±3.00° 28.32±0.85° 58.44±6.00° 28.52±2.90° Manufacturing Example 2-7 103.96±2.83° 24.19±0.24° 59.62±1.43° 24.86±1.40° Manufacturing Example 2-8 114.13±2.53° 20.07±0.41° 58.84±3.10° 20.60±0.20° Manufacturing Example 2-9 113.22±1.47° 19.94±2.20° 54.55±8.12° 13.75±1.02° Manufacturing Example 2-10 114.63±0.18° 13.66±0.42° 55.01±2.48° 10.65±0.92° Uncoated 77.72±4.64° 41.26±4.31° 31.67±6.02° 33.57±0.68°

As shown in Table 3, the contact history angle of Manufacturing Example 2-10 was the lowest, confirming that it had excellent water-repellent/oil-repellent properties. Based on these results, the coating composition according to Manufacturing Example 2-10 was used in Experimental Example 3 described below.

<Experimental Example 3> Evaluation of water-repellent and oil-repellent properties of specimens coated with the coating composition of Manufacturing Example 2-10 on specimens of Examples 1-1 to 1-2

The aluminum 3003 alloy having the microstructured anodic oxide film formed in Examples 1-1 to 1-2 was coated with the coating composition of Manufacturing Example 2-10. The detailed coating process was performed in the same manner as in Experimental Example 2.

For the specimens on which the coating was completed (Examples 2-1 to 2-2), water (purified water) and oil (edible oil) were dropped respectively to evaluate the contact angle and contact history angle, and the results are shown in Table 4 below.

Here, when a metal substrate is anodized to form a POP-shaped microstructure on the surface, a superhydrophilic oxide film is formed. This is an effect caused by the oxygen atoms and microstructure contained in the oxide film. If a hydrophobic coating is applied to the microstructured oxide film with a thin thickness at the level of a monomolecular film to maintain the microstructure, superhydrophobicity can be implemented.

Water(°) Oil(°) Contact angle (0 sec) Contact history angle Contact angle (0 sec) Contact history angle Example 2-1 165.88±18.61 9.78±0.47 73.46±1.11 15.27±1.92 Example 2-2 173.79±12.71 3.19±0.64 75.23±1.04 13.31±1.04

As shown in Table 4 above, it was confirmed that the contact history angles of Examples 2-1 and 2-2 exhibited superhydrophobic and superoleophobic properties, and in particular, it was confirmed that Example 2-2 exhibited excellent effects.

<Experimental Example 4> Derivation of the optimal mixing ratio of cross-linked PDMS derivative of chemical formula 1 and hexane suitable for coating on a substrate having a microstructured oxide film formed

Through the results of the above Experimental Examples 2 and 3, it was confirmed that the coating composition sample of Manufacturing Example 2-10 had excellent coating properties, and also had remarkably excellent water-repellent and oil-repellent properties, and formed a coating film thickness thin enough to maintain the microstructure.

Accordingly, in Experimental Example 4, a contact history angle experiment was conducted in the same manner as in Experimental Example 3 to derive the optimal mixing ratio of a cross-linked PDMS derivative of chemical formula 1 and hexane suitable for coating a substrate having a microstructured oxide film formed thereon, and the results are shown in Table 5.

In Table 5 below, the curing agent and hexane of the coating agent are measured and indicated by weight ratio, and the substrate used was aluminum 3003 alloy having a microstructured oxide film in the form of POP obtained in Example 1-2, and a sample was prepared by drop coating without plasma treatment in the same manner as in Manufacturing Example 2-10.

Example Coating agent mixing weight ratio Contact history angle (°) Hexane Hardener
(chemical formula 1) water Oil 3-1 10 0.01 17.92 ± 0.12 19.3 ± 0.45 3-2 10 0.03 17.71 ± 0.79 18.4 ± 0.41 3-3 10 0.05 3.27 ± 0.46 13.44 ± 0.36 3-4 10 0.07 3.25 ± 0.75 13.38 ± 0.54 3-5 10 0.1 3.19 ± 0.64 13.31 ± 1.04 3-6 10 0.13 3.36 ± 0.57 13.44 ± 0.28 3-7 10 0.15 3.41 ± 0.17 14.31 ± 0.41 3-8 10 0.17 3.55 ± 0.54 14.62 ± 0.52 3-9 10 0.20 15.77 ± 0.41 20.7 ± 0.86

As shown in Table 5 above, in Examples 3-3 to 3-8, it was confirmed that a coating film thickness sufficiently thin to maintain the microstructure was formed, and a coating film was uniformly formed over the entire substrate, so that water-repellent and oil-repellent properties were remarkably excellent. On the other hand, in the case of Examples 3-1 to 3-2, it is expected that the curing agent content was too low and thus the coating film was not formed on some parts of the substrate, and in the case of Example 3-9, it is expected that the curing agent content was too high and thus a coating film that was too thick to maintain the microstructure was formed.

<Experimental Example 5> Contact angle evaluation of Examples 1-1 to 1-2

The contact angles for water (purified water) and oil (edible oil) were measured for the specimens of Examples 1-1 and 1-2 that were not coated, and the results are shown in Table 6 below.

Contact angle (°) Pore expansion time (min) water Oil Example 1-1 35 8.9 ± 3.45 None Example 1-2 40 None None

* None: This means that the contact angle is close to 0 and measurement is not possible.

As shown in Table 2 above, both Examples 1-1 and 1-2 were confirmed to exhibit superhydrophilicity, with contact angles for water and oil being 10° or less.

The present invention has been described with reference to preferred embodiments thereof. Those skilled in the art will appreciate that the present invention may be implemented in modified forms without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a limiting perspective. The scope of the present invention is not set forth in the foregoing description, but rather in the claims, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (18)

A pre-patterning step (step 1) of first anodizing a 3000 series aluminum alloy at 30-50 V for 5-15 hours, and then etching to remove the first anodized film;
Secondary anodizing step (step 2) for 3-5 minutes at 39-41 V;
Step 3: pore widening treatment by immersing in a 0.06-0.14 M phosphoric acid (H ₃ PO ₄ ) solution for 33-42 minutes;
Step 4 of the third anodizing treatment at 39-41 V for 3-5 minutes; and
A step (step 5) of coating with a coating composition comprising a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the following chemical formula 1 and an organic solvent;
The coating composition used in the above step 5 is characterized in that it does not contain a PDMS (Polydimethylsiloxane) derivative represented by the following chemical formula 2,
The coating composition used in the above step 5 is characterized by containing 0.05-0.17 parts by weight of a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 based on 10 parts by weight of an organic solvent.
Method for producing an oil-repellent and water-repellent film on a 3000 series aluminum alloy.
[Chemical Formula 1]

(In the above chemical formula 1, x and y are each an integer from 1 to 30.)

[Chemical formula 2]

(In the above chemical formula 2, m is an integer from 1 to 100.)
In the first paragraph,
A manufacturing method characterized in that the above 3000 series aluminum alloy is at least one selected from the group consisting of Al 3003, Al 3004, Al 3005, Al 3015, Al 3103, Al 3104, and Al 3105.
In the first paragraph,
A manufacturing method characterized in that the anodic oxide film formed on the surface of a 3000 series aluminum alloy through the above steps 1 to 4 has a pillar-on-pore form in which pillars are formed on a pore structure.
delete delete In the first paragraph,
Secondary anodizing step (step 2) at 39.5-40.5 V for 3.8-4.2 minutes;
Step 3: immersing in a 0.095-0.105 M phosphoric acid (H ₃ PO ₄ ) solution for 34-41 minutes to perform pore widening treatment; and
A manufacturing method characterized by including a step (step 4) of performing a third anodizing treatment at 39.5-40.5 V for 3.8-4.2 minutes.
In the first paragraph,
A manufacturing method characterized in that the organic solvent of step 5 is one of pentane, hexane, heptane, and octane.
delete delete delete delete delete delete A 3000 series aluminum alloy having an oil-repellent and water-repellent film formed by the manufacturing method of Article 1.
A pre-patterning step (step 1) of first anodizing a 3000 series aluminum alloy at 30-50 V for 5-15 hours, and then etching to remove the first anodized film;
Step 2: Secondary anodizing treatment at 39-41 V for 4 minutes;
Step 3: immersing in a 0.06-0.14 M phosphoric acid (H ₃ PO ₄ ) solution for 33-42 minutes to perform pore widening treatment; and
Including a step of third anodizing treatment for 4 minutes at 39-41 V (step 4);
A method for manufacturing a superhydrophilic anodic oxide film in the form of pillar-on-pores on the surface of a 3000 series aluminum alloy.
In Article 15,
A manufacturing method characterized in that the above pillar-on-pore type anodized film has pillars formed on a pore structure.
delete A 3000 series aluminum alloy having a pillar-on-pore type anodic oxide film formed by the manufacturing method of Article 15.