KR20220103342A - hydrophobic mesoporous silicas by treatment of non-fluorinated alkylsilane surface, and method for manufacturing the same - Google Patents

Abstract

The present invention relates to hydrophobic mesoporous silica by non-fluorine-based alkylsilane surface treatment and a preparation method thereof. The preparation method comprises the step of: a) adding mesoporous silica to a solution to prepare a mesoporous silica dispersion; and b) adding fluorine-free alkylsilane satisfying chemical formula 1 to the mesoporous silica dispersion and stirring the same to obtain surface-modified mesoporous silica, wherein the solution is pH 0 to 3 or pH 10 to 14.

Description

Hydrophobic mesoporous silicas by treatment of non-fluorinated alkylsilane surface, and method for manufacturing the same

The present invention relates to a hydrophobic mesoporous silica by surface treatment with a non-fluorine-based alkylsilane and a method for preparing the same.

Porous materials are classified as microporous when the pore size is 2 nm or less, mesoporous when the pore size is 2 to 50 nm, and macroporous when the pore size is 50 nm or more. In particular, the mesoporous material may have a high surface area (700 to 1500 m 2 /g) and excellent chemical and thermal stability. In addition, mesoporous material is a chemical reaction catalyst and catalyst carrier because micropores of uniform size are regularly arranged to selectively separate and adsorb molecules at the molecular level and control molecules in the pores. is being utilized Recently, it has been used in various technological fields requiring high specific surface area, such as biosensors such as drug delivery systems and biochemical reaction detection, and fuel cells and energy-related technologies.

One of the mesoporous materials, mesoporous silica, is silica having a pore size of 2 to 50 nm without containing aluminum as a constituent element. Although mesoporous silica exhibits a high specific surface area, it has a problem of low hydrophobicity. Since the mesoporous silica does not have a high water contact angle of 20 to 23°, it is necessary to develop a process method for increasing the surface hydrophobicity of the mesoporous silica. Since the hydrophobic surface can implement properties such as pollution prevention, fogging prevention, and bacterial adhesion prevention, the need for a hydrophobic surface is increasing in various industrial fields.

In the hydrophobic surface realization process, the surface is mainly modified through a sol-gel method. The sol-gel method is a method of modifying a surface through a condensation reaction at a high temperature. The sol-gel method has a problem in that the process is complicated and the cost is increased due to heat treatment. It is necessary to develop a process method for implementing a hydrophobic surface that is simpler than the prior art and can reduce manufacturing costs. In addition, a fluorine-based compound is typically used to implement a hydrophobic surface. The fluorine-based compound has a small atomic diameter and a large electronegativity. Due to these characteristics, the fluorine-based compound easily lowers the surface free energy of the compound. However, fluorine-based compounds have a problem that is harmful not only to the environment but also to the human body. In particular, it has been reported that exposure to fluoride components increases the incidence of incurable diseases such as immune disorders, hormonal disorders, and cancer. Therefore, there have been many restrictions on the use of fluorine-based compounds in recent years. Hydrophobic surface realization technologies are being developed using hydrophobic carbon chain organic materials and non-fluorine-based compounds such as alkyl silanes as a method of lowering surface free energy without using fluorine, which can have a harmful effect on the environment and human body.

There is a need for a method for producing hydrophobic mesoporous silica that can form a low surface free energy without using a fluorine-based compound, realize an excellent hydrophobic surface, and reduce process costs compared to conventional techniques.

As a similar prior document for this, Republic of Korea Patent Publication No. 10-2006-0136388 is disclosed.

Republic of Korea Patent Publication No. 10-2006-0136388 (2006.12.28)

In order to solve the above problems, the present invention forms a low surface free energy without using a fluorine-based compound, so that an excellent hydrophobic surface can be realized, and a non-fluorine-based alkylsilane surface treatment that can reduce process costs compared to the prior art An object of the present invention is to provide a hydrophobic mesoporous silica and a method for preparing the same.

One aspect of the present invention for achieving the above object is a) preparing a mesoporous silica dispersion by adding mesoporous silica to a solution; and

b) adding a non-fluorine-based alkylsilane satisfying the following formula (1) to the mesoporous silica dispersion and stirring to obtain a surface-modified mesoporous silica;

The solution relates to a method for producing hydrophobic mesoporous silica, characterized in that pH 0 to 3 or pH 10 to 14.

[Formula 1]

(In Chemical 1, the R ₁ , R ₂ , and R ₃ is optionally an alkyl having 1 to 3 carbon atoms, and R ₄ is an alkyl having 2 to 6 carbon atoms.)

In one aspect, the solution in step a) may be characterized in that the pH is 12 to 14.

In one aspect, in Formula 1, R ₄ may be an alkyl having 2 to 5 carbon atoms.

In one aspect, the stirring of step b) may be characterized in that it is carried out at 35 to 80 ℃.

In one aspect, the hydrophobic mesoporous silica may be characterized in that it has a water contact angle of 90 ° to 120 °.

In addition, another aspect of the present invention is a hydrophobic mesoporous silica in which the surface of the mesoporous silica is modified with a non-fluorine-based alkylsilane satisfying the following formula (1),

The hydrophobic mesoporous silica relates to a hydrophobic mesoporous silica, characterized in that it has a water contact angle of 90 ° to 120 °.

[Formula 1]

(In Chemical 1, the R ₁ , R ₂ , and R ₃ is optionally an alkyl having 1 to 3 carbon atoms, and R ₄ is an alkyl having 2 to 6 carbon atoms.)

The hydrophobic mesoporous silica by surface treatment with a non-fluorine-based alkylsilane according to the present invention can be surface-modified with a non-fluorine-based short-chain silane that is not harmful to the human body to the mesoporous silica, thereby improving hydrophobicity, and heating the sol-gel (sol-gel) at a high temperature Instead of the gel) method, it is possible to reduce the manufacturing cost compared to the conventional technique by performing a process method of adjusting the pH of the reactant.

Hereinafter, hydrophobic mesoporous silica by surface treatment with a non-fluorine-based alkylsilane according to the present invention and a method for preparing the same will be described in detail. The drawings introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, if there is no other definition in the technical terms and scientific terms used, it has the meaning commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may be unnecessarily obscure will be omitted.

Although mesoporous silica exhibits a high specific surface area, it has a problem of low hydrophobicity. Since the fluorine-based compound has a small atomic diameter and high electronegativity, it is easy to lower the surface free energy of the compound, and is typically used to implement a hydrophobic surface. However, fluorine-based compounds have a problem that is harmful not only to the environment but also to the human body. In addition, the sol-gel method, which is a process method for implementing a hydrophobic surface, has a problem in that the process is complicated and the process cost is increased due to heating because the condensation reaction is performed at a high temperature.

Accordingly, the present inventors have repeatedly studied to develop a method for producing hydrophobic mesoporous silica that can realize an excellent hydrophobic surface and reduce the cost of producing a hydrophobic surface compared to conventional techniques by forming a low surface free energy without using a fluorine-based compound At one end, the above object can be achieved if the surface is modified with a non-fluorine-based short-chain silane that is not harmful to the human body to mesoporous silica and the process method of synthesizing the reaction product by adjusting the pH of the reactant instead of heating it at a high temperature during the condensation reaction. was found and led to the completion of the present invention.

Specifically, the method for preparing hydrophobic mesoporous silica according to an embodiment of the present invention comprises the steps of: a) preparing a mesoporous silica dispersion by adding mesoporous silica to a solution; and

b) adding a non-fluorine-based alkylsilane satisfying the following formula (1) to the mesoporous silica dispersion and stirring to obtain a surface-modified mesoporous silica;

The solution may be characterized as having a pH of 0 to 3 or a pH of 10 to 14.

[Formula 1]

(In Chemical 1, the R ₁ , R ₂ and R ₃ is optionally an alkyl having 1 to 3 carbon atoms, and R ₄ is an alkyl having 2 to 6 carbon atoms.)

As described above, when the surface modification of the mesoporous silica with a non-fluorine-based short-chain silane that is not harmful to the human body is performed, the surface-modified mesoporous silica can form a low surface energy without using a fluorine-based compound, so that an excellent hydrophobic surface can be realized. . In addition, it is possible to reduce the cost of the hydrophobic surface preparation process compared to the prior art by using a short-chain silane and performing a process method for synthesizing by adjusting the pH.

Hereinafter, each step of the method for producing hydrophobic mesoporous silica according to the present invention will be described in more detail.

First, a) step of preparing a mesoporous silica dispersion by adding mesoporous silica to the solution will be described.

In an example of the present invention, the mesoporous silica may be used without particular limitation as long as it is commonly used in the art, and as described below as a non-limiting example, polyethylene oxide-polypropylene oxide-polyethylene oxide (poly (ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) and tetraethyl-orthosilicate (Tetraethyl-orthosilicate, TEOS) may be reacted and then calcined may be used, but is not limited thereto. 0.5 to 5 g, more preferably, 1 to 3 g may be added to 100 mL of the solution, but is not limited thereto.

In one embodiment of the present invention, the solution may be an acidic or basic solution. The acidic solution may be any one or a mixture of two or more selected from the group consisting of hydrochloric acid, nitric acid, and sulfuric acid in distilled water, purified water, and the like diluted, but is not necessarily limited thereto. In addition, the acidic solution may have a pH of 0 to 3, more preferably a pH of 0 to 1. The hydrophobicity of the surface-modified mesoporous silica may be further increased by an acidic solution in a pH range of 0 to 3. On the other hand, when the acidic solution is more than pH 3, the hydrogen bonding of the surface-modified mesoporous silica increases, but the polarity increases and the hydrophobicity may decrease.

In addition, the basic solution may be one or a mixture of two or more selected from the group consisting of sodium hydroxide, potassium hydroxide, and calcium hydroxide diluted in water such as distilled water or purified water, but is not necessarily limited thereto. In addition, the basic solution may have a pH of 10 to 14, more preferably a pH of 12 to 14. The hydrophobicity of the surface-modified mesoporous silica may be further increased by the basic solution in the pH range of 10 to 14. On the other hand, when the basic solution has a pH of less than 10, the hydrophobicity of the surface-modified mesoporous silica may be low due to the small number of hydrogen bonds.

Next, a step of b) adding a non-fluorinated alkylsilane satisfying the following formula (1) to the mesoporous silica dispersion and stirring may be performed to obtain a surface-modified mesoporous silica.

[Formula 1]

(In Chemical 1, the R ₁ , R ₂ and R ₃ is optionally an alkyl having 1 to 3 carbon atoms, and R ₄ is an alkyl having 2 to 6 carbon atoms.)

In step b), the non-fluorinated alkylsilane satisfying Chemical Formula 1 exhibits a high water contact angle even though it is a short-chain alkyl chain, thereby reducing the process cost of hydrophobic mesoporous silica.

In one aspect, the solution in step a) may be characterized in that the pH is 12 to 14. When the hydrophobic mesoporous silica is prepared, by satisfying such a pH range, the surface-modified mesoporous silica becomes more non-polar and hydrogen bonds are further increased, so that hydrophobicity can be more excellently increased.

More preferably, in Formula 1, R ₄ may be an alkyl having 2 to 5 carbon atoms. In general, hydrophobicity increases as the nonpolarity increases as the length of the carbon chain of the functional group increases. The water contact angle can be high. That is, the hydrophobicity of the mesoporous silica surface-modified with a non-fluorine-based alkylsilane having an alkyl chain having 2 to 5 carbon atoms may be more excellent. The non-fluorine-based alkylsilane may be added in an amount of 1 to 20 g, preferably 3 to 10 g, based on 100 mL of the solution, but is not limited thereto.

In one aspect, the stirring of step b) may be characterized in that it is carried out at 35 to 80 ℃, more preferably, it may be characterized in that it is carried out at 40 to 50 ℃.

During the bonding process between the mesoporous silica and the non-fluorinated alkylsilane satisfying Chemical Formula 1, an organic molecular film that is regularly and well aligned on the surface of the mesoporous silica may be formed. By satisfying the reaction temperature of 35 to 80 °C, the mobility of the reacting molecules can be improved. As the reaction temperature increases, the desorption rate of solvent molecules and foreign substances physically adsorbed on the surface of the mesoporous silica increases. In addition, due to the rearrangement of the adsorbate chains, the activation energy barrier can be crossed, so that the surface of the mesoporous silica and the molecules constituting the membrane can be strongly bonded by a chemical bond, so that the surface-modified mesoporous silica has excellent hydrophobicity. can In particular, when the reaction is carried out at a temperature of 40 to 50 ° C, a stronger chemical bond can be formed between the surface of the mesoporous silica and the molecules constituting the film, so the surface-modified mesoporous silica can exhibit better hydrophobicity. have. However, when the reaction temperature exceeds 80 °C, condensation of water vapor may occur between the surface of the mesoporous silica and the molecules forming the film, resulting in loss of hydrophobicity.

The hydrophobic mesoporous silica prepared in this way may be characterized as having a water contact angle of 90° to 120°, and more preferably having a water contact angle of 90° to 115°. The hydrophobic mesoporous silica exhibiting such a high water contact angle may exhibit more excellent effects such as pollution prevention, fogging prevention, and bacterial adhesion prevention.

In addition, another aspect of the present invention relates to a mesoporous silica prepared by the above-described method for preparing mesoporous silica, in detail, the surface of the mesoporous silica is modified with a non-fluorine-based alkylsilane satisfying the following formula (1) As a hydrophobic mesoporous silica, the hydrophobic mesoporous silica relates to a hydrophobic mesoporous silica, characterized in that it has a water contact angle of 90° to 120°.

[Formula 1]

(In Chemical 1, the R ₁ , R ₂ and R ₃ is optionally an alkyl having 1 to 3 carbon atoms, and R ₄ is an alkyl having 2 to 6 carbon atoms.)

In this case, since the mesoporous silica and the non-fluorinated alkylsilane satisfying Chemical Formula 1 are the same as those described above, duplicate descriptions are omitted.

More preferably, the hydrophobic mesoporous silica may be characterized in that it has a water contact angle of 90° to 115°.

The mesoporous silica before surface modification exhibits a low water contact angle of 20 to 23°, but when the surface modification is performed with a non-fluorine-based alkylsilane satisfying Formula 1, the surface energy of the material is lowered, so that the hydrophobic property can be increased. . The surface-modified mesoporous silica may exhibit a high water contact angle due to a low surface energy, and thus may exhibit more excellent effects such as pollution prevention, fogging prevention, and bacterial adhesion prevention.

Hereinafter, the hydrophobic mesoporous silica by surface treatment with a non-fluorine-based alkylsilane according to the present invention and a method for preparing the same will be described in more detail through Examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention. In addition, the unit of additives not specifically described in the specification may be weight %.

[Example 1]

4.0 g of polyethylene oxide-polypropylene oxide-polyethylene oxide (poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide), Pluronic P123) was added to 150 mL of distilled water, followed by stirring at 40 °C for 8 hours. , 8.5 g of Tetraethyl-orthosilicate (TEOS) was dropwise, followed by stirring at 40 °C for 24 hours. After the stirred material was put in a steel bomb, it was put in a vacuum oven and aged at 120° C. for 8 hours. The resulting powder was filtered, washed with water and ethanol, and dried at room temperature. The temperature was applied from room temperature to 550 °C and maintained for 6 hours, followed by calcination to obtain mesoporous silica.

1.0 g of the mesoporous silica was added to 60 mL of hydrochloric acid having a pH of 0, stirred for 2 hours, and then 3.0 g of propyl triethoxysilane (PTES) was added and stirred for 24 hours, followed by a filter. After drying, mesoporous silica surface-modified with a silane compound was obtained.

[Examples 2 to 12, and Comparative Examples 1 to 12]

As shown in Table 1 below, the same procedure as in Example 1 was performed except that the pH of the addition solution and the type of the added silane compound were changed.

[Characteristic evaluation method]

1) Hydrophobicity evaluation

After dropping 10 μL of distilled water on the hydrophobic mesoporous silica at room temperature, the contact angle was measured. A contact angle analysis (UNI-CAM/VA, GIT soft tech, Korea) was used, and the results are shown in Table 1 below.

silane compound solution pH Male contact angle (°) Example 1 propyl triethoxysilane pH 0 93.2 Example 2 pH 2 91.3 Example 3 pH 11 94.8 Example 4 pH 13 110.2 Example 5 pentyl triethoxysilane pH 0 96.5 Example 6 pH 2 94.8 Example 7 pH 11 97.2 Example 8 pH 13 113.5 Example 9 Hexyl Triethoxysilane pH 0 94.1 Example 10 pH 2 91.5 Example 11 pH 11 95.7 Example 12 pH 13 111.3 Comparative Example 1 Octyl Triethoxysilane pH 0 92.6 Comparative Example 2 pH 2 81.3 Comparative Example 3 pH 11 65.5 Comparative Example 4 pH 13 81.1 Comparative Example 5 dodecyl triethoxysilane pH 0 93.8 Comparative Example 6 pH 2 82.1 Comparative Example 7 pH 11 86.1 Comparative Example 8 pH 13 90.8 Comparative Example 9 Octadecyl Triethoxysilane pH 0 95.2 Comparative Example 10 pH 2 83.8 Comparative Example 11 pH 11 94.6 Comparative Example 12 pH 13 94.3

As can be seen from Table 1, Examples 1 to 12 showed a water contact angle of 91.3 to 113.5°, and Comparative Examples 1 to 12 showed a water contact angle of 65.5 to 95.2°.

In particular, in the case of Example 8, as the surface of the mesoporous silica was modified with a short-chain alkylsilane having 5 or less carbon atoms at pH 13, the water contact angle was the highest at 113.5°, and was higher than Comparative Examples 1 to 12 by 48.2° at most. Since the higher the water contact angle, the better the hydrophobicity, so it was found that Example 8 exhibiting the highest water contact angle exhibited the best hydrophobicity. From this, it was clearly confirmed that the hydrophobicity of the mesoporous silica can be most excellently increased when the mesoporous silica is surface-modified with pentyltriethoxysilane at pH 13.

Although the present invention has been described through the specific matters and limited examples as described above, these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and the present invention pertains to Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (6)

a) adding mesoporous silica to the solution to prepare a mesoporous silica dispersion; and
b) adding a non-fluorine-based alkylsilane satisfying the following formula (1) to the mesoporous silica dispersion and stirring to obtain a surface-modified mesoporous silica;
The solution is a method for producing a hydrophobic mesoporous silica, characterized in that pH 0 to 3 or pH 10 to 14.
[Formula 1]

(In Chemistry 1 above,
The R ₁ , R ₂ , and R ₃ is optionally alkyl having 1 to 3 carbon atoms,
wherein R ₄ is an alkyl having 2 to 6 carbon atoms.) The method of claim 1,
The solution of step a) is a method for producing a hydrophobic mesoporous silica, characterized in that the pH of 12 to 14.
The method of claim 1,
In Formula 1, R ₄ is an alkyl having 2 to 5 carbon atoms, a method for producing hydrophobic mesoporous silica.
The method of claim 1,
The stirring in step b) is a method for producing hydrophobic mesoporous silica, characterized in that it is carried out at 35 to 80 ℃.
The method of claim 1,
The method for producing hydrophobic mesoporous silica, characterized in that the hydrophobic mesoporous silica has a water contact angle of 90 ° to 120 °.
A hydrophobic mesoporous silica in which the surface of the mesoporous silica is modified with a non-fluorine-based alkylsilane satisfying the following formula (1),
The hydrophobic mesoporous silica is characterized in that it has a water contact angle of 90 ° to 120 °, hydrophobic mesoporous silica.
[Formula 1]

(In Chemistry 1 above,
The R ₁ , R ₂ , and R ₃ is optionally alkyl having 1 to 3 carbon atoms,
wherein R ₄ is an alkyl having 2 to 6 carbon atoms.)