KR101057476B1 - Water-repellent nanosilica of one-dimensional structure and its synthesis method - Google Patents

Abstract

The present invention synthesizes nanosilica having a water-repellent one-dimensional structure by using a silica precursor having heat resistance in the template of 2-amino-N-dodecylacetamide, which is a surfactant, and exhibits high water repellency compared to conventional silica materials. And a method for synthesizing nanosilica having a water-repellent one-dimensional structure, characterized in that it is an environmentally friendly method according to the recycling of the surfactant as a template, using a silica precursor and a water-repellent silane monomer having heat-resistant properties to the surfactant as a template Synthesis of water-repellent one-dimensional structured nanosilica in which water-repellent chain fluorocarbons and hydrocarbon functional groups are bonded to the surface, and especially nano-silica in one-dimensional structure is synthesized using high self-assembly of peptide surfactant. Surface of micrometer and nanometer structure required By modifying, it exhibits a high linear alignment, crystallinity, high water repellency and thermal stability of one-dimensional compared to the general nano-silica structure, it is an economical and environmentally friendly method according to the pleasant working environment, recycling of the surfactant as a template.

Silica, Nanostructure, Lotus Leaf Effect, Silica, Water Repellency, Silane Monomer

Description

One-Dimensional Superhydrophobic Nanostructured Silica and Its Synthetic Method}

The present invention synthesizes nanosilica having a water-repellent one-dimensional structure by using a silica precursor having heat resistance in the template of 2-amino-N-dodecylacetamide, which is a surfactant, and exhibits high water repellency compared to conventional silica materials. The present invention relates to a water-repellent nanosilica having a one-dimensional structure and a method for synthesizing the same, characterized in that it is an environmentally friendly method according to the recycling of a surfactant, which is a template.

General fabrics, paints, composite membranes, etc. create a high value added by increasing the effectiveness of the use by giving various functionalities to the material used. An example of such a function is a super water-repellent function, such a super water-repellent function is derived from the 'lotus leaf effect'.

The lotus leaf effect is the effect of maintaining the state of the insects, such as lotus leaf, rice leaves of plants and butterflies, always clean, and is due to the 'self-cleaning' ability. The secret of the lotus leaf effect was that in 1975, Professor Wilhelm Barthrod, a botanist at the University of Bonn, Germany, observed the lotus leaf under a high magnification microscope, indicating that micrometer-sized projections were formed on the surface. Then, they found that cilia of nanometer size (nm: 1 billionth of a meter) appeared on the surface of the protrusions. Because of this surface structure, the lotus leaf rolls down without attaching water droplets, and thus has a self-cleaning ability to automatically wash down pollutants.

Products applying the above-mentioned lotus leaf effect in real life also appear one after another, which is also called super water repellent surface technology, which is a field of wet and surface modification technology, by physically chemically modifying the surface of the solid surface When the liquid comes into contact with the surface of the solid, the contact angle is 150 ° or more.As a physicochemical fabrication of the super water-repellent surface for the easy industrial use by identifying the phenomena already occurring in nature, and the analysis of the wet phenomenon and Applied technology.

Industrially, water- and oil-repellent surface technology is applied to the oil repellent processing agent of the paper industry and functional inorganic powder of the cosmetic industry.As a detailed example, Nano-Tex of the United States uses an electrospinning technique. Nano-thick hydrophobic fibers were made. This textile evolved into unspoiled clothing. Nano-Tex also won the 2002 Time Magazine's Invention of the Year award for its clothes. In addition, the super water-repellent self-cleaning surface is applied to everyday life as well as the surface coating of next-generation large displays such as liquid crystal display (LCD) and plasma display panel (PDP) as well as micro-elements such as building exterior materials, chemical and bio-sensors, etc. The application range is expected to be very wide.

And Germany's STO has developed a paint that prevents soiling by using the lotus leaf effect, but this paint is made by mixing pigments of μm and nm size together with the powder constituting the paint to show super water repellency. It does not indicate water repellent performance.

In addition, Professor Cho Gil-won, a professor of chemical engineering at Pohang University of Science and Technology, has developed a surface that can freely control the surface properties of materials by using external stimuli such as light and heat. (J. Am. Chem. Soc, 2006, 128, 14458 -14459). This material also has difficulty in showing continuous surface properties because the material properties are changed by light and heat, and the Korea Institute of Machinery & Materials is researching a large-area transparent super water-repellent film manufacturing technology through plasma treatment. In addition, Dr. Jong-Ju Na, a research team at the Materials Research Institute of the Korea Institute of Machinery & Materials, developed a transparent polymer film that does not contaminate surfaces, such as lotus leaves, by applying plasma and registered this technology in Korea as a Korean patent registration No. 10-0776970 in November 2007. . In the case of this method, there is a concern that a device using plasma is expensive in terms of installation cost and surface treatment, and inferior in heat resistance.

Therefore, the present inventors combine a method of synthesizing an amino acid surfactant (Korean Patent Application No. 10-2008-003925) and a method of synthesizing a one-dimensional nanosilica (Korean Patent Application No. 10-2008-0038509). By using the above it is possible to solve the above problems and to complete the present invention.

Therefore, the present invention for solving the above problems is a chain-type fluorocarbon carbide having water repellency by using a silica precursor and a water repellent silane monomer having heat resistance in the template of the surfactant 2-amino-N-dodecylacetamide and It is an object of the present invention to provide a water-repellent nanosilica having a one-dimensional structure and a method for synthesizing the same, by synthesizing a water-repellent nanosilica bonded to a hydrocarbon functional group on a surface thereof.

In particular, the present invention synthesizes the nanosilica of the one-dimensional structure using the high self-assembly of the peptide surfactant, surface modification to simultaneously have a micrometer, nanometer structure required for showing the water repellency, 1 higher than the general nanosilica structure It is an object of the present invention to provide a water-repellent nanosilica having a one-dimensional structure and a method for synthesizing the same, characterized in that the linear alignment and crystallinity of the dimension and high water repellency and thermal stability.

Therefore, the water-repellent nanosilica according to the present invention, which achieves the above objects, has a water-repellent effect by dropping the chemical surface binding energy of the fluorine group dispersed on the surface of the silica in the form of a one-dimensional column. Due to the fact that the water repellent phenomenon is implemented, it showed a higher water repellency than the general fluorinated nanosilica.

In addition, the present invention is synthesized in the room temperature, neutral, aqueous solution state using a one-dimensional columnar nano-porous silica material having a long vertical channel and a fluorine functional group, and the working environment is comfortable, and economical by recycling the organic solvent as a template It is an object of the present invention to provide a method for synthesizing a water-repellent nanosilica having a one-dimensional structure characterized in that the environmentally friendly method.

The present invention for solving the above problems in the method of synthesizing the nanosilica structure,

Adding a template to water to heat the template mixed aqueous solution to prepare the solution (100);

Allowing the template mixed solution to stand to mix the silica precursor after gelation (200);

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Adding 300 silane monomer having water repellency and grafting the surface of the nanomaterial (300);

Washing the grafted silica precursor mixture with alcohol to recover the template (400);

Drying to remove the alcohol and then calcining the water-repellent nanosilica of the one-dimensional structure having mesopores (500);

A method for synthesizing a water-repellent nanosilica having a one-dimensional structure, which is manufactured through the above, is used as a means for solving the problem.

However, the template in step (100) is characterized in that the use of 2-amino-N-dodecylacetamide as a surfactant as a gel-generator (gel-generator) having the same structure as Compound 1 below.

(화합물 1)

(Compound 1)

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The present invention by means of the above problem solving means by synthesizing the water-repellent nano-silica bonded to the surface of the water-repellent chain fluorinated hydrocarbon and hydrocarbon functional groups using a silica precursor and a water-repellent silane monomer having a heat-resistant property to the mold which is a surfactant It shows higher water repellency than conventional silica materials, and in particular, by modifying silica nanostructures using the high self-assembly of peptide surfactants and surface modification to simultaneously have micrometer and nanometer structures necessary for water repellency, Compared to silica structure, it has high linear dimension, crystallinity, high water repellency and thermal stability, and it is economical and eco-friendly method by recycling surfactant, which is a mold, and it is very important from an industrial point of view. Having .

In order to achieve the above effect, the present invention shows a high water repellency compared to a conventional silica material by using a silica precursor having heat resistance in the mold of 2-amino-N-dodecylacetamide, which is a surfactant, It relates to a one-dimensional water-repellent nano-silica synthesis method characterized in that the environmentally friendly method according to the recycling of the solvent.

Hereinafter, the configuration of the present invention will be described in detail with reference to FIG.

For reference, Figure 1 relates to a process block diagram showing a method for synthesizing a water-repellent nanosilica of a one-dimensional structure according to the present invention.

The present invention is a method for synthesizing a nanosilica structure,

Adding a template to water to heat the template mixed aqueous solution to prepare the solution (100);

Allowing the template mixed solution to stand to mix the silica precursor after gelation (200);

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Adding 300 silane monomer having water repellency and grafting the surface of the nanomaterial (300);

Washing the grafted silica precursor mixture with alcohol to recover the template (400);

Drying to remove the alcohol and then calcining the water-repellent nanosilica of the one-dimensional structure having mesopores (500);

The water-repellent nanosilica of the one-dimensional structure is synthesized through.

In the present invention, the step (100) is a step of preparing a mixed solution of the template solution by heating until the mixed aqueous solution is added to the water becomes transparent, the template used to form the nanostructure is the same as compound 1 below Preference is given to using surfactant 2-amino-N-dodecylacetamide as a gel-generator having a structure.

In this step, 2-amino-N-dodecylacetamide is added to water to dissolve it, and 15 to 25 ml of water is mixed with 1 mmol of 2-amino-N-dodecylacetamide to 60 ± 1 ° C. Heat at a temperature until the solution is clear. When the amount of water to be mixed with respect to 1 mmol of 2-amino-N-dodecylacetamide in the above is less than 15 ml, or when the heating temperature is lower than the above-defined range, there is a possibility that dissolution is difficult, and the amount of water If the amount exceeds 25 ml or the heating temperature exceeds the range defined above, self-assembly is difficult and the yield may be reduced.

(화합물 1)

(Compound 1)

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The step (200) is a step of allowing the mixed solution of the template to stand for 2 hours or more, gelling the silica precursor, and then reheating the solution until the aqueous solution becomes transparent. Reheat at a temperature of ± 1 ° C. until the aqueous surfactant solution is clear. The silica precursor is preferably added 4 to 10 mmol with respect to 1 mmol of 2-amino-N-dodecylacetamide. If the addition amount of the silica precursor is less than 4 mmol, the thickness of the silica may become too thin. If the amount exceeds 10 mmol, the silica outer wall thickness may be too thick, resulting in other structures. In addition, the silica precursor is preferably selected from one of tetraethoxy orthosilicate (TEOS) or tetramethoxy orthosilicate (TMOS).

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In the step (300), the silane monomer having water repellency is added to the gelled silica precursor, and the surface of the nanomaterial is grafted to allow to stand for three days. In this step, the chain having water repellency on the surface of the silica precursor is present. When the fluorocarbon and hydrocarbon functional groups are bonded to the precursor surface, the water-repellent nanosilica according to the present invention gives a water repellent effect by dropping the chemical surface binding energy of the fluorine group dispersed on the silica surface in the one-dimensional columnar form. Due to the co-influence of nanostructures, super water-repellent phenomena are realized, resulting in higher water repellency than conventional silica materials.

In this step, a one-dimensional linear mesoporous nano silica having a long channel length and a fluorine functional group is formed, and the mesoporous silica has a nanostructure as a template, and the molar ratio of water-repellent silane monomer is 1: 0.1 to 0.5 with respect to the silica precursor. Co-condensation synthesis by mixing in the range of. The channel length of the pores formed at this time is 10,000 ~ 50,000 nm. If the molar ratio of the water-repellent silane monomer mixture is less than 0.1, the fluorine group may not be sufficiently bonded to the surface of the nanosilica, and the water-repellent performance may be deteriorated. If the molar ratio of the water-repellent silane monomer mixture is more than 0.5, it may be excessive. There is a risk of waste.

The water-repellent silane monomers usable in the present invention are [CF ₃ (CF ₂ ) ₁ (CH ₂ ) _m ] _n Si (CH ₃ CH ₂ O) _o , [CH ₃ (CH ₂ ) _m ] _n Si (CH ₃ O) It is preferable to select and use 1 type or more from _o . In this case, in the water-repellent silane monomer, l is an integer of 0-21, m is an integer of 0-21, n is an integer of 1-3 o is an integer of 1-3, provided that n + o = 4.

And step (400) is a step of recovering the template by washing the gelled silica precursor mixture with alcohol, washing by adding alcohol to the gelled silica precursor mixture and then recovering the alcohol and the surfactant, the surfactant Self-assembly of molecules forms nanostructures in which mesopores having a pore size of 2 to 5 nm are formed in the silica precursor. The alcohol used in the present invention is recovered by an extraction method using Soxhlet's extractor by selecting one of methyl alcohol, ethyl alcohol, propyl alcohol and butyl alcohol.

And step (500) is a step of drying the silica precursor mixture from which the alcohol and the template is removed, characterized in that the drying at room temperature for at least one day.

Therefore, the mesoporous silica structure synthesized by the above method has a higher alignment, crystallinity and water repellency than the general mesoporous silica structure, and is a mesoporous silica structure having a diameter of 50-100 nm and a size of 1-100 μm in length. In the present invention, since 2-amino-N-dodecylacetamide, a surfactant used as a template, can be easily recovered and reused as an organic solvent, it is economical and environmentally friendly.

For reference, Figure 2 relates to a diagram showing the process of producing a water-repellent nanosilica by bonding to the surface of the nanosilica using a perfluorosilane in accordance with the present invention.

Hereinafter, the configuration of the present invention will be described in more detail based on the following examples, but the present invention is not necessarily limited only to the following examples.

1. Synthesis of Nano-silica of 1-D Structure

(Example 1)

2-amino-N-dodecylacetamide was used as a gel-generator with 1 mmol, and 20 mL of water was added thereto, and the solution was heated at 60 ° C. until the solution became clear. After allowing to stand for more than gelatinization time, 4 mmol of tetraethoxyorthosilicate (TEOS) was added thereto and mixed with a stirrer for 30 minutes, followed by perfluorosilane [CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (CH ₃ CH ₂ O) ₃ ] After the addition of 0.8 mmol (0.8 mmol is the molar ratio of the water-repellent silane monomer 0.2 to 1 mol of the silica precursor), the reaction was co-condensed, followed by standing in a static condition for 3 days to terminate the reaction. Finally, the silica precursor mixture was washed by the extraction method using Soxhlet's extractor using ethanol to recover 2-amino-N-dodecylacetamide, and dried at room temperature for 1 day or more to have water repellency. Nanosilica of one-dimensional structure was synthesized.

(Example 2)

Synthesis of nanosilica having a water-repellent one-dimensional structure by the same method as in Example 1, except that tetraethoxyorthosilicate (TEOS) is a nanosilica of one-dimensional structure having water repellency by putting 10 mmol and a silane monomer at the same time Was synthesized.

(Comparative Example 1)

Synthesis of the nano-silica of the one-dimensional structure by the same method as in Example 1, except for the step of adding a perfluorosilane silica nanostructure was synthesized.

2. Evaluation of Water Repellency (or Water Repellency) of Nanosilica of 1-D Structure with Water Repellency

In order to evaluate the water repellency (or water repellency) of the one-dimensional nanosilica powder having water repellency, the powder was evenly bonded to the adhesive surface of the post-it and then water repellent experiment was performed on the surface.

The water repellency test of Examples 1, 2 and Comparative Example 1 was carried out by measuring the contact angle of water having a diameter of 1mm size, the results are as shown in Table 1 below.

Evaluation item Example Comparative example One 2 One Contact angle (°) 161 152 30

As evaluated above, in Examples 1 and 2, a chain-type carbonization having water repellency using a silica precursor having a heat resistance property and a water repellent silane monomer in the template of 2-amino-N-dodecyl acetamide, which is a surfactant, was used. Fluorine was bonded to the surface to synthesize nanosilica having a water-repellent one-dimensional structure. In Example 1, as shown in FIG. 3A, the contact angle of the nano silica having no CF water repeller was measured, and the contact angle reached 161 °, and the water repellency effect was obtained by a large sliding angle of 161 °. As shown in FIG. 3B, Example 2 measured the contact angle of the nano-silica as shown in FIG. 3B, and the contact angle reached 152 °. As in Example 1, the water repellency effect was increased due to the large sliding angle of 152 °. Although it was found, Comparative Example 1 measured the contact angle of the nano silica as shown in Figure 3c, the contact angle was found to have little water repellency effect due to a small sliding angle of 30 °.

In addition, as a result of analyzing the water-repellent nanosilica of Example 1 as shown in FIG. 4A (1,000 times magnification), FIG. 4B (5,000 times magnification), 4c (70,000 times magnification) and TEM, FIG. 4D (5,000 times) As shown in the enlarged image), the linear structure having a one-dimensional structure has a width of about 50 to 100 nm, and the nano-silica structure having a linear shape is present in the form of a bundle and has a length of 10 to 100 μm. .

In the FT-IR measurement results of the sample of Example 1, as shown in the graph of FIG. 5, typical CF stretching vibrations were shown at 1224 cm ⁻¹ and 1159 cm ⁻¹ , so that the CF group was attached to the surface of the silica nanostructure. I could confirm it.

In addition, TGA analysis of the water-repellent nanosilica of Example 1 showed that perfluorosilane [CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (CH ₃ CH ₂ O) ₃ ] and When added to tetraethylorthosilicate, it was found that the organic matter on the surface of the water-repellent nano silica decomposed at about 473 ° C.

And as a result of analyzing the water-repellent nanosilica of Example 2 by SEM, the length of the linear structure having a one-dimensional structure as shown in Figure 7a (5,000 times magnification) and Figure 7b (20,000 times magnification) taken by TEM It could be seen that the nanosilica structures having a linear width of about 50 to 100 nm exist independently.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated.

1 is a process block diagram showing the synthesis process of the water-repellent nanosilica structure according to the present invention,

Figure 2 is a schematic diagram showing a process for producing a water-repellent nano-silica by bonding to the surface of the nano-silica using perchlorosilane in accordance with the present invention,

Figure 3a is a photograph showing a state measured the contact angle of the water-repellent nano-silica structure according to Example 1 of the present invention,

3b is a photograph showing a state in which a contact angle of the water repellent nano silica structure according to Example 2 of the present invention is measured;

3c is a photograph showing a state in which a contact angle of the nanosilica structure according to Comparative Example 1 is measured;

Figure 4a is a SEM photograph showing a 1000 times magnification of the water-repellent nano-silica structure according to Example 1 of the present invention,

Figure 4b is a SEM photograph showing a magnified 5,000 times the water-repellent nano-silica structure according to Example 1 of the present invention,

Figure 4c is a SEM photograph showing a 70,000-fold magnification of the water-repellent nano-silica structure according to Example 1 of the present invention,

Figure 4d is a TEM photograph showing a 5,000 times magnification of the water-repellent nano-silica structure according to Example 1 of the present invention,

5 is a graph showing the FT-IR measurement results of the water-repellent nano-silica structure according to Example 1 of the present invention.

Figure 6 is a graph showing the TGA measurement results of the water-repellent nano-silica structure according to Example 1 of the present invention,

Figure 7a is a SEM photograph showing a magnified 5000 times the water-repellent nano-silica structure according to Example 2 of the present invention,

FIG. 7B is a SEM photograph showing a 20,000-fold magnification of a water repellent nano silica structure according to Example 2 of the present invention.

Claims (9)

In the method of synthesizing the nanosilica structure, Adding a template to water to heat the template mixed aqueous solution to prepare the solution (100); Allowing the template mixed solution to stand to mix the silica precursor after gelation (200); Adding 300 silane monomer having water repellency and grafting the surface of the nanomaterial (300); Washing the grafted silica precursor mixture with alcohol to recover the template (400); Drying to remove the alcohol and then calcining the water-repellent nanosilica of the one-dimensional structure having mesopores (500); A method for synthesizing a water repellent nanosilica having a one-dimensional structure, which is prepared through. The method of claim 1, In the step (100), the template is a one-dimensional structure comprising using 2-amino-N-dodecylacetamide as a surfactant as a gel-generator having a structure similar to that of Compound 1 below. Water repellent nano silica synthesis method.

(Compound 1) 3. The method of claim 2, In the step (100), 1-25 ml of water is mixed with 1 mmol of 2-amino-N-dodecylacetamide and heated until the solution becomes transparent at a temperature of 60 ± 1 ° C. Method for synthesizing water repellent nanosilica of structure. The method of claim 1, In step (200), the silica precursor is water-soluble nanosilica synthesis method of one-dimensional structure, characterized in that by adding 4 ~ 10 mmol with respect to 1 mmol of 2-amino-N- dodecyl acetamide. The method of claim 1, In step (300), the stationary water-repellent nano-silica synthesis method of the one-dimensional structure, characterized in that for three days to stand. The method of claim 1, The water-repellent silane monomer is a water-repellent nano-silica synthesis method of the one-dimensional structure, characterized in that by mixing the water-repellent silane monomer in the range of molar ratio of 1: 0.1 to 0.5 with respect to the silica precursor. The method of claim 1, In step (300), the water-repellent silane monomer is [CF ₃ (CF ₂ ) ₁ (CH ₂ ) _m ] _n Si (CH ₃ CH ₂ O) _o , [CH ₃ (CH ₂ ) _m ] _n Si (CH ₃ O 1) _o A water-repellent nano-silica synthesis method of the one-dimensional structure, characterized in that one or more selected from the use. In this case, in the water-repellent silane monomer, l is an integer of 0-21, m is an integer of 0-21, n is an integer of 1-3 o is an integer of 1-3, provided that n + o = 4. delete The water-repellent nanosilica having a one-dimensional structure having water-repellent properties having a diameter of 50 to 100 nm and a length of 1 to 100 μm by the synthesis method of any one of the synthesis methods of claims 1 to 7.

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