KR102754969B1 - Development of Superhydrophobic and Superhydrophilic Anodic Oxidation of Titanium in Oxalic Acid Electrolyte - Google Patents

Abstract

The present invention relates to the development of superhydrophobic and superhydrophilic anodized titanium in an oxalic acid electrolyte. The method for forming an ultra-superhydrophilic oxide film and an ultra-superhydrophobic oxide film on the surface of titanium according to the present invention has the effect of realizing excellent hydrophilicity with a contact angle of 5° or less and excellent hydrophobicity with a contact angle of 175° or more, respectively, by optimizing the type of electrolyte and the anodizing treatment conditions.

Description

{Development of Superhydrophobic and Superhydrophilic Anodic Oxidation of Titanium in Oxalic Acid Electrolyte}

The present invention relates to the development of superhydrophobic and superhydrophilic anodic titanium oxide in an oxalic acid electrolyte.

Titanium has been used industrially since the 1950s, and has been rapidly developed as an aerospace material with excellent physical properties such as high strength, heat resistance, and corrosion resistance. Titanium has a specific gravity of 4.54 g/cm3, making it lighter than iron (Fe) but having the highest specific strength among metals. It is used not only for aircraft, ship, automobile parts, and bulletproof materials, but also for medical devices and implants due to its biosafety and compatibility.

Pure titanium (CP Titanium), which is less expensive than titanium alloys, is divided into grades 1, 2, 3, and 4 according to the difference in the content of impurities such as nitrogen (N), carbon (C), hydrogen (H), oxygen (O), and iron (Fe), and there are differences in mechanical properties such as tensile strength and elongation. Among them, Ti-grade 4 has relatively low formability, but it has the highest strength and excellent durability, so it is mainly used as an industrial and medical material such as heat exchangers and surgical hardware.

The greatest advantages of titanium used as an industrial and medical material, its excellent corrosion resistance and durability, are due to the existence of a strong passive film, which is a naturally formed oxide film on the surface, which allows rapid recovery even if the titanium surface is damaged, and thus shows strong resistance to corrosion. However, titanium cannot avoid crevice corrosion or pitting in solutions with a high iron content, in places where it comes into contact with iron, or in a seawater environment, and it shows a characteristic of being vulnerable to corrosion. Recently, research has been conducted to improve biocompatibility by modifying the oxide film of titanium and to apply it as a bone fixation plate and surgical biomaterial, and among them, a method of forming a porous oxide film with properties similar to human bone for high bonding strength and adhesion is attracting attention. Therefore, in order to improve corrosion resistance in a corrosive environment such as seawater or to enhance suitability as a medical material, it is necessary to modify the titanium oxide film.

Surface treatments to improve the physical properties or biocompatibility of titanium include plating, plasma electrolytic oxidation, and anodic oxidation. Among them, the most actively studied method for producing an oxide film of a desired shape on the titanium surface or improving corrosion resistance is anodic oxidation, which can produce an artificial oxide film by reacting titanium with oxygen using an electrochemical method.

By controlling the type and temperature of the anodic oxidation electrolyte, the applied voltage, and the processing time, nano-sized pores and nano- and micro-sized thicknesses can be formed on the surface, and various insulating properties or liquid wettability can be implemented depending on the formed structure, such as nanotubes, nanosheets, and nanoarrays.

Wetting is the ability of a liquid to maintain contact with a solid surface, and is caused by molecular interactions that occur when a liquid and a solid meet. The contact angle at equilibrium on a uniform and smooth surface without an oxide film is as shown in Figure 1a, and can be expressed by Young's equation, which is the following mathematical equation 1.

[Mathematical Formula 1]

γ _lg cosθ = γ _sg - γ _sl

γ _sg is the interfacial free energy between solid and gas.

γ _sl is the interfacial free energy between solid and liquid.

γ _lg is the interfacial free energy between liquid and gas.

θ is the contact angle.

When a droplet fills a groove or pore created by anodic oxidation, the contact angle has a shape as in Fig. 1b, and can be explained by mathematical equation 2 and the Wenzel model. When a droplet comes into contact with a surface having a nanostructure, Cosθ ₀ is converted to Cosθ _wenzel , where γ is a factor representing the roughness. The Wenzel model states that as the roughness of the solid surface becomes rougher, the absorption of the droplet becomes smoother, so a hydrophilic surface appears. Fig. 1c is an image showing wettability on a water-repellent surface, and can be explained by the Cassie-Baxter model and mathematical equation 3. The Cassie-Baxter model states that as the surface becomes rougher, a higher contact angle appears, and in this state, a high contact angle of the droplet means that the area where the droplet and the solid come into contact is small. Here, when a nanostructure and a droplet come into contact, Cosθ ₀ is converted to Cosθ _{Cassie-Baxter} , and when the surface wetted by the droplet is f, the contact angle Cosθ _{Cassie-Baxter} can have a surface that does not get wet even when the droplet touches the surface if it is larger than Cos ^-1 {(f-1)(rf)}. Through this model, hydrophilicity and water repellency can be explained, and it can be seen that a droplet in a Cassie-Baxter state flows more fluidly on a solid surface than a droplet in a Wenzel state.

[Mathematical formula 2]

[Mathematical Formula 3]

There are Ti grades 1 to 4, which are classified as pure titanium with a titanium content of 99 wt% or more, and contain C, Fe, H, N, and O elements of 1 wt% or less. Titanium alloys contain approximately 90 wt% of titanium and approximately 10 wt% of the remaining elements. For example, Ti-6Al-4V grade 5 titanium alloy may contain approximately 6 wt% of Al, approximately 4 wt% of V, approximately 90 wt% of Ti, and trace amounts of Fe and O elements.

Since the conditions for the intended anodizing treatment may vary depending on the titanium content, the titanium content of the titanium substrate to be treated is important.

The present invention performed anodization on Ti-grade 4 material, and formed an oxide film by controlling the type and concentration of electrolyte as variables and keeping all other conditions the same. The shape and chemical composition of the oxide film formed differently depending on the type and concentration of electrolyte were confirmed, and the insulating properties were compared through resistance measurements. In addition, in order to observe the difference in wettability due to surface roughness and coating, the roughness and contact angle before coating were observed and compared with the contact angle after coating.

Registered Patent No. 10-1832059

Object 1 of the present invention is to provide a method for forming an ultra super hydrophilic oxide film on a titanium surface.

Object 2 of the present invention is to provide a method for forming an ultra super hydrophobic oxide film on a titanium surface.

Object 3 of the present invention is to provide titanium having an ultra super hydrophilic oxide film formed thereon by the above method.

Object 4 of the present invention is to provide titanium having an ultra super hydrophobic oxide film formed by the above method.

To achieve the above purpose,

The present invention comprises a step of washing and polishing a titanium (Ti) substrate (step 1); and

Step 2: a step of forming a hydrophilic oxide film on the surface of titanium (Ti) by anodizing the titanium (Ti) treated in step 1 at 35-45 V for 5-7 hours;

The present invention provides a method for forming an ultra-super hydrophilic oxide film on a titanium surface, characterized in that the electrolyte used in the anodic oxidation treatment of step 2 above is 0.2-0.4 M oxalic acid.

The above titanium may be any one of Ti grades 1 to 4 having a Ti content of 99 wt% or more.

The polishing in step 1 above can apply at least one of electrochemical polishing and chemical polishing, and any polishing method known in the art can be applied without any restrictions.

The electrolyte for the anodizing treatment in the above step 2 may be 0.2-0.4 M oxalic acid, preferably 0.25-0.35 M oxalic acid, more preferably 0.28-0.32 M oxalic acid, and particularly preferably 0.29-0.31 M oxalic acid. If an electrolyte based on ethylene glycol rather than oxalic acid is used, ultra-superhydrophilicity and ultra-superhydrophobicity may not be achieved.

The oxide film formed by the method of forming an ultra super hydrophilic oxide film on a titanium surface according to the present invention is characterized by having a hydrophilicity of a contact angle of 5° or less.

The above step 2 can be performed by anodizing polished titanium (Ti) at 35-45 V for 5-7 hours, preferably at 38-42 V for 5.5-6.5 hours, and more preferably at 39-41 V for 5.9-6.1 hours. If the above anodizing conditions are exceeded, ultra-superhydrophilicity and ultra-superhydrophobicity may not be achieved.

In addition, the present invention provides titanium having an ultra super hydrophilic oxide film formed by the above method.

Furthermore, the present invention comprises a step of washing and polishing a titanium (Ti) substrate (step 1);

Step 2: Anodizing titanium (Ti) treated in step 1 at 35-45 V for 5-7 hours to form a hydrophilic oxide film on the titanium surface; and

A step (step 3) of coating with a hydrophobic coating agent capable of monolayer coating;

The present invention provides a method for forming an ultra-super hydrophobic oxide film on a titanium surface, characterized in that the electrolyte used in the anodic oxidation treatment of step 2 above is 0.2-0.4 M oxalic acid.

The above titanium may be any one of Ti grades 1 to 4 having a Ti content of 99 wt% or more.

The polishing in step 1 above can apply at least one of electrochemical polishing and chemical polishing, and any polishing method known in the art can be applied without any restrictions.

The electrolyte for the anodizing treatment in the above step 2 may be 0.2-0.4 M oxalic acid, preferably 0.25-0.35 M oxalic acid, more preferably 0.28-0.32 M oxalic acid, and particularly preferably 0.29-0.31 M oxalic acid. If an electrolyte based on ethylene glycol rather than oxalic acid is used, ultra-superhydrophilicity and ultra-superhydrophobicity may not be achieved.

The oxide film formed by the method of forming an ultra super hydrophilic oxide film on a titanium surface according to the present invention is characterized by having a hydrophilicity of a contact angle of 5° or less.

The above step 2 can be performed by anodizing polished titanium (Ti) at 35-45 V for 5-7 hours, preferably at 38-42 V for 5.5-6.5 hours, and more preferably at 39-41 V for 5.9-6.1 hours. If the above anodizing conditions are exceeded, ultra-superhydrophilicity and ultra-superhydrophobicity may not be achieved.

The above step 3 is a step of coating with a hydrophobic coating agent capable of monolayer coating. The hydrophobic coating agent capable of monolayer coating may be FDTS (1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane), and may also be a coating composition (Korean Laid-Open Publication No. 10-2022-0109277) containing a cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 and one organic solvent selected from the group consisting of pentane, hexane, heptane, and octane. Preferably, the coating composition may contain 0.05 to 0.17 parts by weight of the cross-linked PDMS (Polydimethylsiloxane) derivative represented by the chemical formula 1 based on 10 parts by weight of the organic solvent.

[Chemical Formula 1]

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

In addition, the present invention provides titanium having an ultra super hydrophobic oxide film formed by the above method.

The method for forming an ultra-superhydrophilic oxide film and an ultra-superhydrophobic oxide film on a titanium surface according to the present invention has the effect of realizing excellent hydrophilicity of a contact angle of 5° or less and excellent hydrophobicity of 175° or more, respectively, by optimizing the type of electrolyte and the anodizing treatment conditions.

Figure 1a is an image showing the contact angle at equilibrium on a uniform and smooth surface on which no oxide film has been formed.
Figure 1b is an image showing the contact angle when a droplet fills a groove or pore created by anodic oxidation based on the Wenzel model.
Figure 1c is an image showing wettability on a hydrophobic surface based on the Cassie-Baxter model.
Figure 2 is an image of the shape of the oxide film according to the anodic oxidation electrolyte in Example 1.
Figure 3 is an image of the surface and cross-section of an oxide film according to the anodic oxidation electrolyte in Example 1, taken using FE-SEM.
Figure 4 is a graph showing the change in element content before and after the anodic oxidation process according to the anodic oxidation electrolyte in Example 1, measured using energy dispersive spectroscopy (EDS).
Figure 5 is an image showing the roughness of the oxide film after anodic oxidation according to the electrolyte using an atomic force microscope.
Figure 6 is a photograph of the contact angle of the anodic oxide film according to three types of electrolytes in Example 1 (hydrophobic coating X) and Example 2 (hydrophobic coating O).
Figure 7 is an image of the shape of a water droplet according to the surface area where the droplet comes into contact with the nanostructure when a hydrophobic coating is applied to an anodic oxide film.

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.

<Example 1> Manufacturing of superhydrophilic anodic oxide film through anodic oxidation treatment of Ti grade 4 titanium

Step 1: Cleaning and electropolishing of Ti grade 4 titanium substrate

The experiment was conducted by processing the titanium substrate to a working size of 2.5 × 3 × 0.1 cm. In order to remove foreign substances and impurities remaining on the surface, ultrasonic cleaning was performed for 10 minutes each by immersing in acetone, ethanol, and distilled water. After washing the specimen, electrolytic polishing was performed for 10 minutes at a voltage of 35 V using a mixture of perchloric acid (70%) and acetic acid in a volume ratio of 1:5 to remove the natural oxide film on the surface.

Step 2: Anodizing

Prior to anodizing, variables were placed on the type of anodizing electrolyte to vary the morphological differences of the oxide film.

Electrolyte A: 0.3M oxalic acid

Electrolyte B: Ethylene glycol based, containing 1 M NH ₄ F and 0.1 MH ₂ O

Electrolyte C: Ethylene glycol based, containing 0.07 M NH ₄ F and 1 MH ₂ O

The anodizing treatment conditions were to apply a voltage of 40 V at 0℃ for 6 hours to form a superhydrophilic anodizing film.

The specimens manufactured according to electrolytes A to C were named specimens A, B, and C, respectively.

<Example 2> Manufacturing of superhydrophobic anodic oxide film through anodizing treatment and hydrophobic coating of Ti grade 4 titanium

Steps 1 and 2 of Example 1 were performed in the same manner, and then a hydrophobic coating agent with low surface energy was coated to implement a water-repellent surface. The hydrophobic coating method is described in Step 3 below.

Step 3: Hydrophobic coating

After removing impurities remaining on the surface using a plasma device prior to coating, FDTS (1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane), a substance with low surface energy, was applied and dried on a heating plate at 150°C for 10 minutes to perform self-assembled monolayer (SAM) coating.

<Experimental Example 1> Confirmation of the shape of the anodic oxidation film according to the electrolyte type

In Example 1, the shape of the anodic oxide film according to three types of electrolytes was confirmed.

Specifically, the surface morphological differences of the anodic oxide film formed depending on the type of electrolyte were observed using a field emission scanning electron microscope (FE-SEM) after anodic oxidation, and energy dispersive spectroscopy (EDS) was used to confirm the components and contents of the oxide film.

Figure 2 is an image of the shape of the oxide film according to the anodic oxidation electrolyte in Example 1.

Figure 3 is an image of the surface and cross-section of an oxide film according to the anodic oxidation electrolyte in Example 1, taken using FE-SEM.

As shown in Figs. 2 and 3, a titanium pinecone nanostructure (TPS) was formed in specimen A, and a porous oxide film was formed in specimens B and C. The thicknesses of the oxide films formed on specimens A, B, and C were measured to be 7.07±0.41 ㎛, 1.51±0.05 ㎛, and 4.50±0.12 ㎛, respectively. The thickest oxide film was formed in specimen A, and the thickness decreased in the order of specimens C and B. This shows that the shape and thickness of the oxide film are formed differently depending on the type of electrolyte even under the same voltage and time conditions.

Figure 4 is a graph showing the change in element content before and after the anodic oxidation process according to the anodic oxidation electrolyte in Example 1, measured using energy dispersive spectroscopy (EDS).

As shown in Fig. 4, oxygen (O) and titanium (Ti) were found to be the main components after anodic oxidation, and carbon (C) and fluorine (F) were detected in addition. Here, carbon is believed to have been detected by the EDS detection equipment, the stage and carbon tape, and fluorine is thought to have been detected only in specimens B and C due to the influence of _NH4F added to the anodic oxidation solution.

Table 1 shows the quantitative analysis results of the components observed by EDS. The contents of titanium and oxygen were 92.95 wt% and 4.11 wt% in the untreated titanium Ti-grade 4 specimen, 64.11 wt% and 33.25 wt% in the A specimen, 56.63 wt% and 26.70 wt% in the B electrolyte, and 53.07 wt% and 30.72 wt% in the C electrolyte. Considering that the titanium content of all specimens decreased and the oxygen content increased after anodization, it is judged that some of the titanium was converted to an oxide film.

<Experimental Example 2> Evaluation of insulation properties of anodic oxide film according to electrolyte type

In Example 1, the insulating properties of the anodic oxide film according to three types of electrolytes were evaluated.

Specifically, the insulation characteristics of untreated titanium specimens and anodized specimens according to each electrolyte were observed using a digital multimeter (DMM).

The results of measuring the insulation resistance by the structure of the titanium anodic oxide film are shown in Table 2. The resistance value of specimen C was the highest at 5.269 × 10 ⁴ KΩ, followed by specimens B and A, which had lower resistance values at 1.035 × 10 ⁴ KΩ and 1.35 KΩ, respectively. Although the thickest oxide film was formed on specimen A, it is thought that the lowest resistance value was measured because the titanium base material was easily observed around most of the irregularly formed nanostructures. In addition, when comparing specimens B and C with porous oxide films formed, it is thought that the resistance was measured the highest because the C specimen had an oxide film that was about three times thicker than the B specimen, which played a superior role in protecting the base material.

<Experimental Example 3> Observation of the roughness of the anodic oxidation film according to the type of electrolyte

In Example 1, the roughness of the anodic oxide film according to three types of electrolytes was observed.

Specifically, an atomic force microscope (AFM) was used to observe the roughness of the formed oxide film.

Figure 5 is an image showing the roughness of the oxide film after anodic oxidation according to the electrolyte using an atomic force microscope.

The average surface roughness R _a values from the reference surface to the designated surface in Fig. 5 are shown in Table 3.

As shown in Fig. 5 and Table 3, the roughness of specimen B had the highest value of 39.39 nm, followed by specimen A and specimen C, which were measured at 20.02 nm and 15.86 nm, respectively. As can be observed in the image in Fig. 3, specimen A has a wide gap between structures, while specimen C has a regular pore structure, which suggests that the roughness is lower than that of specimen B. It is thought that specimen B has a relatively dense oxide film and an uneven pore structure compared to specimens A and C, resulting in high roughness.

<Experimental Example 4> Evaluation of hydrophilic and water-repellent properties

In Example 1 (hydrophobic coating X) and Example 2 (hydrophobic coating O), the hydrophilic and hydrophobic properties of the anodic oxide film according to three types of electrolytes were evaluated.

Specifically, in order to observe the hydrophilic and water-repellent properties, the contact angle was measured five times each using 3 μL of distilled water at room temperature and the average was calculated. The advancing and receding angles were measured five times each on the water-repellent coated sample using the captive method to calculate the contact hysteresis angle.

Figure 6 is a photograph of the contact angle of the anodic oxide film according to three types of electrolytes in Example 1 (hydrophobic coating X) and Example 2 (hydrophobic coating O).

The contact angle and contact history angle are shown in Table 4.

As shown in Fig. 6 and Table 4, before coating, the contact angle of specimen A was not measured because the droplet spread quickly, while that of specimen B was measured to be 8.67±2.08° and that of specimen C was measured to be 8.89±2.82°, indicating that superhydrophilicity was observed for all specimens A, B, and C. It is believed that the gaps between the pine cone-shaped structures formed in specimen A were wide and unevenly distributed, allowing the droplets to easily penetrate into the base material. Although the contact angle of specimen B was higher than that of specimen A due to the formation of a relatively dense oxide film, it is thought that hydrophilicity was observed due to the roughness and irregular pores formed on the surface. Although specimen C had lower roughness than specimen B, the droplet was absorbed into the regular pore structure of the surface, so a hydrophilic contact angle similar to that of specimen B was observed. After coating, the water-repellent contact angles were measured as 178.99±1.31°, 131.91±5.97°, and 136.97±2.31° for specimens A, B, and C in that order, and the contact hysteresis angles were measured as 2.34±1.25°, 14.68±3.45°, and 7.39±2.11°, respectively.

Figure 7 is an image of the shape of a water droplet according to the surface area where the droplet comes into contact with the nanostructure when a hydrophobic coating is applied to an anodic oxide film.

As shown in Fig. 7, when a structure is formed through anodic oxidation and coated with a material having low surface energy, the air trapped between the structures acts to support the droplets, resulting in water repellency. In addition, the structure formed in Fig. 7a has a smaller surface area in contact with the droplets than that in Fig. 7b, resulting in higher water repellency, which can be explained by the Cassie-Baxter model as shown in mathematical expression 3.

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 restrictive perspective. The scope of the present invention is not set forth in the foregoing description, but in the claims, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (17)

Step of cleaning and polishing a titanium (Ti) substrate (Step 1); and
Step 2: a step of forming a hydrophilic oxide film on the surface of titanium (Ti) by anodizing the titanium (Ti) treated in step 1 at 35-45 V for 5-7 hours;
A method for forming an ultra-super hydrophilic oxide film on a titanium surface, characterized in that the electrolyte used in the anodic oxidation treatment of step 2 above is 0.2-0.4 M oxalic acid.
In the first paragraph,
A method for forming an ultra-super hydrophilic oxide film on a titanium surface, characterized in that the titanium is any one of Ti grades 1 to 4 having a Ti content of 99 wt% or more.
In the first paragraph,
A method for forming an ultra-super hydrophilic oxide film on a titanium surface, characterized in that the polishing of the above step 1 is at least one of electrochemical polishing and chemical polishing.
In the first paragraph,
A method for forming an ultra-super hydrophilic oxide film on a titanium surface, characterized in that the anodizing electrolyte of step 2 above is 0.25-0.35 M oxalic acid.
In paragraph 4,
A method for forming an ultra-super hydrophilic oxide film on a titanium surface, characterized in that the anodizing electrolyte of step 2 above is 0.28-0.32 M oxalic acid.
In the first paragraph,
A method for forming an ultra super hydrophilic oxide film on a titanium surface, characterized in that it has a hydrophilicity of a contact angle of 5° or less.
Titanium having an ultra super hydrophilic oxide film formed by the method of claim 1.
Step of cleaning and polishing the titanium (Ti) substrate (Step 1);
Step 2: Anodizing titanium (Ti) treated in step 1 at 35-45 V for 5-7 hours to form a hydrophilic oxide film on the titanium surface; and
A step (step 3) of coating with a hydrophobic coating agent capable of monolayer coating;
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the electrolyte used in the anodic oxidation treatment of step 2 above is 0.2-0.4 M oxalic acid.
In Article 8,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the titanium is any one of Ti grades 1 to 4 having a Ti content of 99 wt% or more.
In Article 8,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the polishing of the above step 1 is at least one of electrochemical polishing and chemical polishing.
In Article 8,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the anodizing electrolyte of step 2 above is 0.25-0.35 M oxalic acid.
In Article 11,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the anodizing electrolyte of step 2 above is 0.28-0.32 M oxalic acid.
In Article 8,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that it has an ultra super hydrophobicity of a contact angle of 175° or more.
In Article 8,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the hydrophobic coating agent of step 3 above is FDTS (1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane).
In Article 8,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that the hydrophobic coating agent of step 3 is a coating composition containing a cross-linked PDMS (Polydimethylsiloxane) derivative represented by chemical formula 1 and one organic solvent selected from pentane, hexane, heptane, and octane.
[Chemical Formula 1]

(In the above chemical formula 1, x and y are each an integer from 1 to 30.)
In Article 15,
A method for forming an ultra super hydrophobic oxide film on a titanium surface, characterized in that it comprises 0.05 to 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.
Titanium having an ultra super hydrophobic oxide film formed by the method of claim 8.