KR20130082217A - Hybrid transparent coating material having superhydrophobicity and method of the material - Google Patents

Abstract

PURPOSE: A hybrid coating material, which is transparent and pliable, is provided to transparently coat an object, to be applied in self-cleaning coating and anti-fouling coating and to have superhydrophobic and super water-repellent properties due to the production of a hybrid material of silica aerogel and polyalkoxysilane. CONSTITUTION: A hybrid coating material comprises polyalkyl siloxane and silica aerogel. The polyalkyl siloxane and silica aerogel are mixed at a weight ratio of 5:1-1:1 to have superhydrophobic and super water-repellent properties. A manufacturing method of the hybrid coating material comprises the steps of: manufacturing polyalkyl siloxane and producing silica aerogel.

Description

Hybrid transparent coating material having superhydrophobicity and method for the production thereof

The present invention relates to a hybrid transparent coating material having a superhydrophobic and super water-repellent and a method for manufacturing the same, and more particularly, hybrid transparent coating showing a transparent, stable, superhydrophobic and superhydrophobic property using polyalkylsiloxane and silica airgel. It relates to a material and a method of manufacturing the same.

The wettability of water on the material surface is known to be adjustable by controlling the surface chemical treatment and surface structure. In general, the contact angle with water on the surface having water repellent properties can be reached up to 100 ~ 120 ° through chemical treatment on a smooth surface. When the surface having such chemical properties increases the surface roughness of the micro or nano pattern, the contact angle reaches 150 to 170 °, which is called a super water-repellent surface.

On the super water-repellent surface, water droplets do not form on the surface, and when contacted, the water slides and leaves the surface. During this process, the surface can be automatically cleaned, which is called self-cleaning. This effect is easily observed on the surface of the lotus leaf.

This property can be applied to microfluidic devices and used as a channel inner wall surface with less resistance to flow of fluids and droplets. When a large amount of energy is required to flow a fluid such as water onto a solid surface, it is a great constraint for the application of the surface, particularly for applications involving the flow of fluid. In most applications, the static contact angle and contact angle hysteresis characteristics of water droplets flowing over the surface are important indicators.

The increase in the contact angle of rough surfaces can be explained using the following two models. Wenzel assumes that the area under the water droplets is completely wet. In this case, the rough surface has the effect of increasing the contact area between the solid and the liquid, thereby increasing the contact angle. Cassie and Baxter, on the other hand, assume that air remains trapped on the surface under water droplets. As a result, the contact area between the solid and the water droplets decreases and the contact angle increases. The surface with double roughness here increases the contact angle of water droplets in air on the same principle.

Contact angle histories have been reported based on thermodynamic models. Lafuma and Quere showed that the contact angle history of wet surfaces is greater than that of composite surfaces with the effect of fixing the liquid. McHale et al. Theoretically predicted that wet surfaces have good adsorptive properties, while slipping on synthetic surfaces. Previous studies have suggested reducing the contact area between a solid and a liquid to obtain a superhydrophobic surface with a small contact angle history.

Korean Patent Publication No. 2009-0115783 discloses a Ceylon crosslinkable one-component silicone rubber composition comprising hydrophobic silica. The document discloses a room temperature crosslinked one-component silicone rubber composition comprising hydrophobic silica and organopolysiloxane. However, the desired degree of superhydrophobicity and superhydrophobicity could not be obtained, and there was a problem of rubber composition.

Recently, many researchers have studied the double roughness surface that mimics the lotus leaf to obtain the surface with self-purifying effect. Patankar does not provide enough mention of contact angle history, but theoretically suggests that double roughness surfaces exhibit higher water repellency than single roughness surfaces. In the experiment, several methods were used to measure the superhydrophobicity using the contact angle history on the surface of double roughness. However, single roughness surface with proper surface treatment showed similar characteristics to slippery surface. Therefore, there is a problem that the superhydrophobic slippery surface is hardly considered to be due to the double surface roughness.

In order to solve the above problems, an object of the present invention is to provide a hybrid transparent coating material exhibiting superhydrophobic, superhydrophobic and oleophobic characteristics by using two materials.

In order to solve the above problems, an object of the present invention is to provide a method for producing a hybrid transparent coating material exhibiting superhydrophobic, superhydrophobic and oleophobic characteristics by using two materials.

In order to solve the above problems, an object of the present invention is to provide a transparent coating film formed from a hybrid transparent coating material exhibiting superhydrophobic, superhydrophobic and oleophobic characteristics by using two materials.

In order to achieve the above object,

Polyalkylsiloxanes; And a hybrid material composed of silica airgel,

Provided is a hybrid transparent coating material having superhydrophobic and superhydrophobic characteristics in which the polyalkylsiloxane and silica airgel are mixed at a weight ratio of 5: 1 to 1: 1.

To achieve these and other objects,

Forming a polyalkylsiloxane;

Forming a silica airgel; And

The polyalkylsiloxane and silica airgel are mixed in a weight ratio of 5: 1 to 1: 1, respectively, to provide a method for preparing a hybrid transparent coating material having superhydrophobic and superhydrophobic characteristics.

According to another aspect of the present invention,

It provides a hybrid transparent coating film having a superhydrophobic and super water-repellent characteristics formed using the transparent coating material.

The transparent coating material according to the present invention forms a hybrid material of silica airgel and polyalkoxysilane, and is transparent and flexible, and can exhibit superhydrophobicity and superhydrophobicity so that the transparent coating material can be transparently coated without harming the aesthetics of the material to be coated. It can be applied by self-cleaning coating or antifouling coating.

1 is a graph measuring the transparency after coating the glass substrate MA, MB, MC, MD, ME according to an embodiment of the present invention.
Figure 2 is a graph measuring the transparency after coating the glass substrate EA, EB, EC, ED, EE according to an embodiment of the present invention.
Figure 3 shows a transparency picture of MA, MB, MC, MD, ME according to an embodiment of the present invention.
Figure 4 shows a transparency picture of EA, EB, EC, ED, EE according to another embodiment of the present invention.
5 and 6 illustrate SEM image photographs according to an embodiment of the present invention.
7 and 8 show AFM image photographs of silica airgel according to one embodiment of the invention.
9 and 10 show AFM image photographs of a silica aerogel and a polymer hybrid material according to one embodiment of the invention.
11 and 12 illustrate contact angles of hybrid materials in accordance with one embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

Whenever a component is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements, not the exclusion of any other element, unless the context clearly dictates otherwise.

The present invention is polyalkylsiloxane; And a hybrid material composed of silica airgel, which provides a hybrid transparent coating material having superhydrophobic and superhydrophobic property in which the polyalkylsiloxane and silica airgel are mixed in an appropriate weight ratio.

The present invention provides a method for producing a transparent coating material and a transparent coating material for producing a very small coating film by controlling the roughness of the coating surface by hybridizing a silica airgel having a very small number of properties with a modified polyalkylsiloxane polymer. It is for. It can also be applied as a self-cleaning coating or antifouling coating.

In the present invention, the polyalkylsiloxane and the silica airgel are preferably mixed in a weight ratio of 5: 1 to 1: 1. If the polyalkylsiloxane content is greater than 5: 1 by weight relative to the silica airgel, the content of the silica airgel is too small to obtain the superhydrophobic effect required by the present invention, and thus the polyalkylsiloxane content is not included in the silica airgel. When the ratio is less than 1: 1 by weight, the content of the silica airgel is too high and the surface of the coating film becomes cloudy, which is not preferable because the transparency sharply decreases.

Polyalkylsiloxanes used as polymers have excellent hydrophobicity, transparency, flexibility, stability, and the like, and are inexpensive and are advantageous for commercialization. Polyalkylsiloxane polymers used in conjunction with silica airgels contribute significantly to improving the superhydrophobic properties of hybrid materials. In addition, the transparency of the polymer on which the hybrid material is based increases the applicability of the material, giving it the advantage of coating transparently without compromising the aesthetics of the material to be coated.

In addition, the polyalkylsiloxane itself has a flexible network structure, which also makes the hybrid material made flexible, which enables curved coatings and contributes to very few properties after coating.

The polyalkylsiloxane is preferably one selected from polymethylsiloxane and polyethylsiloxane. Wherein the polyalkylsiloxane can be obtained from one selected from polymethylhydroxysiloxane and polyethylhydroxysiloxane.

The silica airgel material has a very small number by itself, and when hybridized with the polyalkylsiloxane polymer, the ultrahydrophobic property of the airgel material is further improved, and a superhydrophobic hybrid material having increased transparency and stability can be prepared.

The silica airgel may be selected from methyltrimethoxysilane or methyltriethoxysilane. Silica airgel may be prepared under an alcohol solvent by hydrolysis and condensation reaction of polymethyltrialkoxysilane (CH ₂ ) _n (eg n = 1 to 8). Specifically, the silica airgel forms a mixture of methyltriethoxysilane and alcohol (e.g. methanol), add oxalic acid solution to the mixture, stir, add ammonium hydroxide solution and add alcohol (e.g. methanol) It can be obtained by addition and then homogenization.

In addition, in order to clearly distinguish the hybrid technology showing the conventional superhydrophobicity, the silica airgel was used in the embodiment of the present invention, not simply a silica material. Aerogels have a structure containing micropores, and have an alias of being the lightest solid in the world because its apparent density is lighter than air.

One of the conditions for exhibiting the ultra-small properties is to increase the surface roughness of the material. When the surface roughness increases, the shape of the air layer under the water layer is formed, thereby realizing a very small number of properties. Aerogels have this structure, making them well suited for superhydrophobic hybrid materials.

Surface roughness RMS value of the transparent material according to the present invention is preferably 200 to 250nm. Increasing the value of RMS means that the surface roughness increases accordingly. In general, silica airgel shows about 86.0 nm to 116.0 nm by itself, and thus the surface roughness is greatly increased by preparing a hybrid material by adding polyalkylsiloxane. Therefore, the surface roughness of the material is increased by the hybridization according to the present invention, it can be said that the superhydrophobicity and superhydrophobicity are increased.

The hybrid transparent coating material synthesized according to the present invention preferably has a contact angle with water (Static Contact Angle of water drops) of 140 to 180 °. As mentioned above, since the normal contact angle with the water droplet is generally 150 to 170 °, the surface may be referred to as a super water-repellent surface, and thus, the transparent coating material according to the present invention may sufficiently exhibit super water-repellent properties.

According to another embodiment of the present invention, there is provided a hybrid transparent coating film having a super hydrophobic and super water-repellent characteristics formed using the transparent coating material.

As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. The description of the present invention is for the purpose of illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described below are exemplary in all respects and not restrictive.

Example

Silica Aerogel  synthesis

Example  A

1 g of methyltrimethoxysilane and 9.740 g of methyl alcohol were mixed with 0.5 g (0.001 g) of oxalic acid solution, stirred for 30 minutes, and left at room temperature for 24 hours. 0.61 g (11.2 M) of ammonium hydroxide solution was further added, stirred for 15 minutes, and left at room temperature for 48 hours. 10 g of methanol was mixed and homogenized for 5 minutes, followed by spin coating at 2000 rpm for 1 minute on glass. It was dried overnight at room temperature.

Example  B

1 g of methyltriethoxysilane and 9.740 g of methyl alcohol were mixed with 0.5 g (0.001 g) of oxalic acid solution, stirred for 30 minutes, and left at room temperature for 24 hours. 0.61 g (11.2 M) of ammonium hydroxide solution was further added, stirred for 15 minutes, and left at room temperature for 48 hours. 10 g of methanol was mixed and homogenized for 5 minutes, followed by spin coating at 2000 rpm for 1 minute on glass. It was dried overnight at room temperature.

Of polymethylhydroxysiloxane  synthesis

4.70 g of polymethylhydroxysilane and 70 ml of ethanol were mixed and stirred for 5 minutes. Add 0.008 g of sodium hydroxide solution and stir at room temperature for 24 hours. The polymethylsiloxane (PMOH) gel was dried at 80 ° C., ground, washed several times with 2 mL of water and vacuum dried at 40 ° C. to produce PMOHs powder.

Polymethylsiloxane / Silica Aerogels Hybrid  synthesis

Example  A-1

0.1 g of polymethylhydroxysiloxane (PMOHs) and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.02 g of silica aerogels obtained from Example A and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica aerogel hybrid (MB). The process for preparing the polymethylsiloxane and silica airgel hybrid materials is shown in Scheme 1 below.

<Reaction Scheme 1>

Example  A-2

0.1 g of PMOHs and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.05 g of the silica airgel obtained in Example A and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica aerogel hybrid (MC).

Example  A-3

0.1 g of PMOHs and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.08 g of silica aerogels obtained from Example A and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica aerogel hybrid (MD).

Example  A-4

0.1 g of PMOHs and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.1 g of silica aerogels obtained from Example A and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica airgel hybrid (ME).

Comparative example  A-1

4.70 g of polymethylhydroxysilane and 70 ml of ethanol were mixed and stirred for 5 minutes. Add 0.008 g of sodium hydroxide solution and stir at room temperature for 24 hours. The polymethylsiloxane (PMOH) gel was dried at 80 ° C., ground, washed several times with 2 mL of water and vacuum dried at 40 ° C. to produce PMOHs powder.

0.1 g of PMOHs and methanol were mixed and stirred for 5 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane polymer (MA) was formed and spincoated on glass for 1 minute at 2000 rpm. Complete by drying overnight at room temperature.

Example  B-1

0.1 g of polymethylhydroxysiloxane (PMOHs) and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.02 g of silica aerogels obtained from Example B and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica airgel hybrid (EB).

Example  B-2

0.1 g of polymethylhydroxysiloxane (PMOHs) and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.05 g of the silica airgel obtained in Example B and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica airgel hybrid (EC).

Example  B-3

0.1 g of polymethylhydroxysiloxane (PMOHs) and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.08 g of silica aerogel obtained from Example B and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica airgel hybrid (ED).

Example  B-4

0.1 g of polymethylhydroxysiloxane (PMOHs) and 5 g of methanol were mixed and stirred for 5 minutes. Subsequently, 0.1 g of the silica airgel obtained in Example B and 5 g of methanol were mixed and stirred at room temperature for 15 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane and silica airgel hybrids were formed and spincoated on glass for 1 minute at 2000 rpm. Drying at room temperature overnight completed the polymethylsiloxane / silica aerogel hybrid (EE).

Comparative example  B-1

4.70 g of polymethylhydroxysilane and 70 ml of ethanol were mixed and stirred for 5 minutes. Add 0.008 g of sodium hydroxide solution and stir at room temperature for 24 hours. The polymethylsiloxane (PMOH) gel was dried at 80 ° C., ground, washed several times with 2 mL of water and vacuum dried at 40 ° C. to produce PMOHs powder.

0.1 g of PMOHs and 5 g of methanol were mixed and stirred for 5 minutes. The water was further mixed and stirred for 24 hours. Polymethylsiloxane polymer (EA) was formed and spincoated on glass for 1 minute at 2000 rpm. Complete by drying overnight at room temperature. Polymethylsiloxane polymer (EA) obtained by the comparative example B-1 shows the component substantially the same as the comparative example A-1.

Results and rating

1 is a graph measuring the transparency after coating the samples on a glass substrate according to an embodiment of the present invention. Referring to FIG. 1, it can be seen that the transparency of all five samples is more than 80% and the tendency of transparency increases as the content of silica airgel decreases (in the order of ME, MD, MC, MB, MA). see. This is because as the content of silica airgel increases, more networks are formed in the hybrid material, thus causing a hazy color. As more network structures are formed, it can be seen that as the nanostructures are formed, fine roughness of nano and micro size is formed on the surface to increase the ultra-small properties of the material.

2 is a graph measuring the transparency of the samples coated on a glass substrate according to an embodiment of the present invention. Referring to FIG. 2, it can be seen that the transparency of all five samples is more than 68%, and the transparency tends to increase as the silica airgel content decreases (in the order of EE, ED, EC, EB, and EA). see. This is because as the content of silica airgel increases, more networks are formed in the hybrid material, thus causing a hazy color. As more network structures are formed, it can be seen that as the nanostructures are formed, fine roughness of nano and micro size is formed on the surface to increase the ultra-small properties of the material. The opacity of the samples of FIG. 2 compared to the samples of FIG. 1 seems to be due to the formation of more networks in the E series samples compared to the M series samples. Instead of lowering the transparency, the ultra-small feature was further increased.

Figure 3 shows a transparency picture of MA, MB, MC, MD, ME according to an embodiment of the present invention, Figure 4 is a transparency of EA, EB, EC, ED, EE according to another embodiment of the present invention Show a picture. 3 and 4 are photographed directly after the spin coating of the hybrid material on the glass substrate, the transparency of the film can be confirmed again through this data.

5 and 6 are SEM image photographs according to an embodiment of the present invention.

Referring to FIG. 5, the state of the surface can be confirmed. Specifically, the network structure of the silica airgel and the polymer can be seen to become more complicated as the content of the silica airgel prepared from methyltrimethoxysilane increases. This fact is consistent with the contents of Figure 1, it can be seen that the surface roughness increases as the content of the silica airgel increases, showing a very small characteristic.

Referring to Figure 6, it can be confirmed in the state of the surface, specifically, the network structure of the silica airgel and the polymer can be seen that the complexity increases as the content of the silica airgel prepared from methyltriethoxysilane. This fact is also consistent with the contents of Figure 2, it can be seen that the surface roughness increases as the content of the silica airgel increases, showing a very few properties.

7 and 8 show AFM image photographs of silica airgel according to one embodiment of the invention. 7 and 8, the RMS value of the silica airgel prepared from methyltrimethoxysilane (mtms) is 86.582nm, the RMS value of the silica airgel prepared from methyltriethoxysilane (mtes) is 115.22nm silica It can be seen that the airgel alone has a relatively high RMS value.

9 and 10 are AFM image photographs of a silica airgel and a polymer hybrid material according to an embodiment of the present invention. 9 and 10, in the case of silica aerogels and polymer hybrid materials, the RMS value of the silica airgel was 207.07 nm and the EE of 244.23 nm, respectively. It can be seen that, after the hybridization of the silica airgel and the polymer, the ultra-small properties of the material increased.

11 and 12 illustrate contact angles with water droplets of a hybrid material according to an embodiment of the present invention. Referring to Figure 11, in the case of a hybrid material containing a silica airgel prepared from methyltrimethoxysilane (MTMS) ((b) MB ~ (e) ME) does not contain a hybrid material [(a) MA Compared with], the hydrophobic property is improved, and as the content of silica airgel increases, the hydrophobic property of the hybrid material also increases. Referring to FIG. 12, in the case of a hybrid material containing silica airgel prepared from methyltriethoxysilane (MTES) ((b ′) EB to (e ′) EE), the hybrid material does not include the hybrid material [(a Compared to ') EA', the hydrophobicity is improved, and as the content of silica airgel increases, the hydrophobicity of the hybrid material increases.

From the above results, the hybrid materials containing silica aerogels prepared from methyltrimethoxysilane (MTMS) and methyltriethoxysilane (MTES) are more free than silica aerosols (MA, EA). The hydrophobicity was improved and as the content of silica airgel increased, the hydrophobicity of the hybrid material also increased.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (9)

Polyalkylsiloxanes; And a hybrid material composed of silica airgel,
Hybrid coating material having a superhydrophobic and super water-repellent mixture of the polyalkylsiloxane and silica airgel in a 5: 1 to 1: 1 weight ratio.
The method of claim 1,
The polyalkylsiloxane is a hybrid coating material, characterized in that one selected from polymethylsiloxane and polyethylsiloxane.
The method of claim 1,
The silica airgel is a hybrid coating material, characterized in that prepared from one or more selected from the group consisting of methyltrimethoxysilane and methyltriethoxysilane.
The method of claim 1,
A hybrid coating material, characterized in that the contact angle with water is 140 to 180 °.
The method of claim 1,
Surface roughness RMS value of the coating material is a hybrid coating material, characterized in that 200 to 250nm.
Forming a polyalkylsiloxane;
Forming a silica airgel; And
5. A method for producing a hybrid coating material having superhydrophobic and superhydrophobic characteristics by mixing the polyalkylsiloxane and silica airgel in a weight ratio of 5: 1 to 1: 1, respectively.
The method according to claim 6,
The polyalkylsiloxane is a method for producing a hybrid coating material, characterized in that obtained from one selected from polymethylhydroxysiloxane and polyethylhydroxysiloxane.
The method according to claim 6,
The silica airgel forming a mixture of methyltriethoxysilane and alcohol;
Adding and stirring an oxalic acid solution to the mixture; And
Method for producing a hybrid coating material comprising the step of adding an ammonium hydroxide solution and adding alcohol and then homogenizing.
A hybrid coating film having superhydrophobic and superhydrophobic characteristics formed using the material according to any one of claims 1 to 5.

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