KR100581391B1 - Preparation of silicon oxide nanotube with functional group and application thereof - Google Patents

Abstract

The present invention relates to a method for producing a nanotube having a functional group that can eliminate the surface modification step is a challenge in the application of nanotubes.

Silicon nanotubes having functional groups can be prepared by sol-gel reaction of a mixed solution including functional silane using nanometer-sized nanostructured porous aluminum oxide template.

Silicon oxide nanotubes having a functional group according to the present invention is advantageous in forming a composite because it can be combined with various materials by changing the kind of functional groups, and can be used in various nanodevices.

Functional Groups, Silanes, Nanotubes, Sol-Gel Reactions

Description

Preparation method of silicon oxide nanotube with functional group and application to device {Preparation of silicon oxide nanotube with functional group and application}

1 and 2 are SEM photographs of the nanotubes prepared using 3-mercetopropyltrimethoxysilane (the magnification of FIG. 1 is 100,000, and the magnification of FIG. 2 is 10,000).

3 is a SEM photograph (magnification: 15,000) of nanotubes prepared using 3-aminopropyltriethoxysilane.

FIG. 4 is a SEM photograph (magnification: 50,000) of the reaction of the gold substrate with the mucto functional group of the nanotube prepared using 3-merctopropyltrimethoxysilane.

5 is an IR spectrum of nanotubes prepared using 3-aminopropyltriethoxysilane.

The present invention relates to a method for producing a nanotube having a functional group that eliminates the surface modification step that is a challenge in the application of nanotubes, and more particularly, a sol-gel method using a solution containing a silane having various functional groups. It relates to a nanotube manufactured by.

The main bond in the nanotube consists of Si—O and the functional group X is selected from an amine group or a mercto group.

Although inorganic nanotubes are currently being studied, they show limitations that they can be applied through the surface modification step despite being effective device components. For example, even in the step of placing nanotubes on a substrate, this leads to the problem of fixing them. In other words, there are various reasons for the limitation of nanotubes applied to the device, but it can be said that it is basically due to the surface modification of nanotubes. As it progresses to the stage, there are bound to be many limitations in device application.

Nanotubes were formed in 1991 by Dr. Iijima using an electrodischarge method to analyze carbon masses formed on graphite cathodes with a transmission electron microscope (TEM). Nano Tube (CNT) was discovered and published for the first time in Nature. These carbon nanotubes are superior to any materials in terms of mechanical, electrical and chemical properties so far, and are well suited to the characteristics of electrical and electronic devices in terms of their size. Therefore, the use of memory devices, FEDs (Field Emission Display) and the like are being actively studied. However, carbon nanotubes must maintain a high temperature in the manufacturing process, the growth and purification process of nanotubes is very complicated, and manufacturing costs are expensive. Therefore, since these problems have emerged, studies have been conducted to synthesize various types of nanotubes such as semiconductor nanowires as well as metal nanotubes and use them in nanodevices.

Nanotubes of silicon oxide are known as good photoluminescence materials and much research is being conducted. (Bo Zeng et al. Adv. Mater., 2002, 14, 122) In particular, research has been conducted to increase the efficiency of phosphorescence by incorporating other materials into nanotubes of silicon oxide and to apply them in real life and high-tech industries. If the surface is not modified, it is difficult to combine with other materials, so there is a limit to the application to nanodevices. Thus, there is a need to manufacture nanotubes with functional groups.

In addition, the nanotubes must have a constant diameter and length for nanodevice applications. Therefore, various methods for synthesizing nanotubes have been developed. Among them, when the nanotubes are manufactured using aluminum oxide as a template, the diameters and lengths of the nanotubes are known to be constant.

Therefore, in the present invention, the development of nanotubes having a constant diameter and length while having a functional group capable of forming a composite with other materials using anodized porous aluminum oxide as a template is a technical problem to be solved.

That is, the first technical problem to be achieved by the present invention is that the nano-size allows for application to fine electronic devices and at the same time unlike the existing carbon nanotubes, the manufacturing process is easy and the diameter and length can be easily adjusted. To provide nanotubes with functional groups that can form complexes with other superior materials.

The second technical problem to be achieved by the present invention is to provide a method for producing a nanotube having a functional group.

The present invention relates to a silicon oxide nanotube having a functional group, which is obtained by sol-gel polymerization of a precursor of formula (1), wherein in formula (1), R is linear or branched alkylene and R ¹ , R ² and R ³ are each the same or different straight or branched alkyl, A is NR ⁴ R ⁵ or SR ⁶ , and R ⁴ , R ⁵ and R ⁶ are the same or different hydrogen, straight chain alkyl, branched alkyl, cyclic alkyl or Alkyl containing hydrocarbon rings.

Formula (1)

In particular, the present invention relates to a silicon oxide nanotube having a functional group, characterized in that the precursor is 3-aminopropyltriethoxysilane or 3-mercetopropyltrimethoxysilane.

The invention also

(a) adding a precursor of formula (1) to the solvent and stirring to prepare a sol solution;

(b) immersing the nanostructured porous aluminum oxide template in the sol solution,

(c) drying the porous aluminum oxide template and

(d) removing the aluminum oxide template from the porous aluminum oxide template into which the nanotube is inserted to obtain a nanotube having a functional group. .

Formula (1)

In formula (1), R is straight or branched alkylene and R ¹ , R ² and R ³ are the same or different straight or branched alkyl, A is NR ⁴ R ⁵ or SR ⁶ , R ⁴ , R ⁵ and R ⁶ is alkyl, including the same or different hydrogen, straight chain alkyl, branched chain alkyl, cyclic alkyl or hydrocarbon ring.

The present invention also relates to a method for producing a nanotube, characterized in that the solvent of step (a) consists of a mixed solution of methyltrimethoxysilane, H ₂ O and ethanol.

In another aspect, the present invention relates to a method for producing a nanotube, characterized in that the step of removing the porous aluminum oxide template is to immerse the porous material in a solution mixed with ethanol, water and NaOH.

Hereinafter, the present invention will be described in more detail.

The precursor used for the preparation of the nanotubes past the functional group according to the present invention is shown in the following formula (1).

Formula (1)

In formula (1), R is straight or branched alkylene, R ¹ , R ² and R ³ are the same or different straight or branched alkyl, A is NR ⁴ R ⁵ or SR ⁶ , R ⁴ , R ⁵ and R ⁶ is alkyl, including the same or different hydrogen, straight chain alkyl, branched chain alkyl, cyclic alkyl or hydrocarbon ring. Preferable carbon number of the said alkylene group is 3-5, Preferable carbon number of the said alkyl group is 1-10, More preferably, it is 1-5. The number of ring carbons of the cyclic alkyl or hydrocarbon ring is preferably 3 to 7.

Preferred as the precursor material are 3-aminopropyltriethoxysilane or 3-mercetopropyltrimethoxysilane.

The functional groups of the nanotubes prepared by the present invention are alkylamines and alkylmercetos, and these functional groups can complex with various materials.

Examples of the material capable of forming a composite with the nanotubes of the present invention include gold nanoparticles and ruthenium complexes. Gold nanoparticles can be used as catalysts and ruthenium complexes can be applied to devices capable of photoreaction systems.

Hereinafter, a method of manufacturing a nanotube using the precursor will be described in detail.

This method is somewhat similar to M. Zhang et al. (J. Mater. Sci. Lett. 1999, 18, 1911), which produced SiO ₂ nanowires, but the silicon oxide produced had no functional groups at all. There is a difference.

That is, the silane precursor having a functional group is mixed with a mixed solution of methyltrimethoxysilane, ethanol and water to form a well dispersed solution, and condensation reaction results in a sol state. After dipping nanoscale porous aluminum oxide into the reaction solution, it is taken out and dried in air to make a gel state. Thereafter, thermal drying under nitrogen at 150 ° C. produces a silicon oxide nanotube having a functional group.

In the process of making the sol-gel solution, the state of the solution, that is, the reaction temperature, the type and the molar ratio of the solvent and the precursor affect the production of the nanotubes. Preferred reaction temperature is 15 ~ 20 ℃, the reaction solvent is preferably a mixed solvent of an alkyl alkoxysilane, alcohol, and H ₂ O, and more preferably methyl trimethoxysilane, a mixture of H ₂ O and ethanol. The concentration of the precursor in the reaction solution is preferably 10 to 30% of the mixed solution, more preferably 20%.

The present invention can control the diameter and length of the silicon oxide nanotubes obtained by controlling the nanosize of the porous aluminum oxide template used. The porous aluminum oxide template may be prepared by an electrical oxidation method in sulfuric acid or oxalic acid, and specific methods are as follows.

In one step, an electropolishing process is performed to make the high purity (99.999%) aluminum more pure. That is, ethanol and perchloric acid (perchlolic acid) is mixed at a ratio of 5: 1, and then treated at 15.0 V for 2 minutes at 3 ° C to obtain smooth and high purity aluminum.

 In the second step, using pure aluminum as the positive electrode (positive electrode) and carbon plate as the negative electrode (cathode) electrode, a constant voltage of 25 V in a 0.5 M sulfuric acid solution at 0 ° C. Porous aluminum oxide templates are produced.

On the other hand, if it is necessary to make the diameter or shape of the template more regular, remove the template manufactured in step 2 and perform the second step again. The length of the template can be adjusted in proportion to the time taken, and the diameter of the template can also be adjusted by adjusting the applied voltage. If oxalic acid is used instead of sulfuric acid, it can be oxidized by reacting at 40V for 24h.

The diameter of the aluminum oxide usable in the present invention is preferably 60 to 80 nm, preferably 5 to 15 µm in length, and more preferably 10 µm.

 On the other hand, since the nanotubes prepared according to the above method are synthesized in a porous aluminum oxide template, in order to obtain nanotubes having pure functional groups, a solution in which ethanol, water and sodium hydroxide are mixed in an appropriate ratio, preferably, ethanol and The aluminum oxide template is removed by dipping 0.1 M sodium hydroxide in a 1: 1 mixture by volume.

Hereinafter, one embodiment of the present invention will be described in more detail with reference to the following examples, which are intended for the purpose of description and are not intended to limit the present invention.

Example 1

Methyltrimethoxysilane, ethanol, and water were mixed at 1: 4: 2, and 3-merctopropyltrimethoxysilane was mixed at a ratio of 2 to form a well dispersed solution, and condensation reaction was carried out for 20 hours. To sol. The nano-sized porous aluminum oxide was immersed in the sol solution for about 1 hour, then taken out and dried in air for 12 hours to obtain a gel state. Then, silicon oxide nanotubes are manufactured by heat drying at 150 ° C. for 2 hours under nitrogen.

The nanotubes are immersed in a solution in which ethanol, water and sodium hydroxide are mixed in an appropriate ratio to remove the aluminum oxide template and recover the silicon oxide nanotubes with 3-merctopropyl functional groups.

SEM photographs of the nanotubes prepared using the 3-mermethopropyltrimethoxysilane are shown in FIGS. 1 and 2.

Example 2

Methyltrimethoxysilane, ethanol, and water were mixed at 1: 4: 2, and 3-aminopropyltriethoxysilane was mixed at a ratio of 4 to synthesize silicon oxide nanotubes having 3-aminopropyl functional groups. do. SEM photographs and IR spectra of the prepared nanotubes are shown in FIGS. 3 and 5, respectively.

It can be seen that the nano-sized tube is produced by the present invention by the SEM photograph of FIGS. 1 to 3.

Example 3

Meanwhile, the nanotubes prepared in Example 1 were reacted with the gold substrate in order to determine the complex formation ability with other materials. Remove the alumina template, pour twice the ethanol into the solution with only the nanotubes remaining, soak the gold substrate and let stand for 24 hours. Then remove the gold plate, soak in pure ethanol and proceed for 30 minutes in an ultrasonic cleaner.

FIG. 4 is a SEM photograph of the reaction of the gold substrate with the mucto functional group of the nanotube prepared using 3-merctopropyltrimethoxysilane.

As described above, the present invention can not only make nanotubes of silicon oxide samples having excellent processability and economical cost, but also have functional groups, without undergoing the surface modification step that has been limited in the application of conventional nano devices. Since it can form a complex with other materials, it can be applied to various fields.

Claims (11)

A silicon oxide nanotube having a functional group, which is obtained by sol-gel polymerization of a precursor of formula (1).

Formula (1) In formula (1), R is straight or branched alkylene and R ¹ , R ² and R ³ are the same or different straight or branched alkyl, A is NR ⁴ R ⁵ or SR ⁶ , R ⁴ , R ⁵ and R ⁶ is alkyl, including the same or different hydrogen, straight chain alkyl, branched chain alkyl, cyclic alkyl or hydrocarbon ring. The silicon oxide nanotubes of claim 1, wherein A is NH ₂ or SH. 3. The functional group according to claim 2, wherein R is straight or branched alkylene having 3 to 5 carbon atoms, and R ¹ , R ² and R ³ are each the same or different straight or branched chain alkyl having 1 to 5 carbon atoms. Silicon oxide nanotubes. 4. The silicon oxide nanotubes of claim 3, wherein the precursor is 3-aminopropyltriethoxysilane or 3-mercetopropyltrimethoxysilane. (a) adding a precursor of formula (1) to the solvent and stirring to prepare a sol solution; (b) immersing the nanostructured porous aluminum oxide template in the sol solution, (c) drying the porous aluminum oxide template and (d) removing the aluminum oxide template from the porous aluminum oxide template into which the nanotubes are inserted to obtain a nanotube having a functional group.

Formula (1) In formula (1), R is straight or branched alkylene and R ¹ , R ² and R ³ are the same or different straight or branched alkyl, A is NR ⁴ R ⁵ or SR ⁶ , R ⁴ , R ⁵ and R ⁶ is alkyl, including the same or different hydrogen, straight chain alkyl, branched chain alkyl, cyclic alkyl or hydrocarbon ring. 6. The silicon oxide nanotubes of claim 5, wherein A is NH ₂ or SH. The method of claim 5, wherein the solvent of step (a) is a mixed solution of methyltrimethoxysilane, H ₂ O and ethanol. The method of claim 5, wherein the porous aluminum oxide template is a porous structure having a diameter of 60 to 80 nm and a length of 10 μm. The method of claim 5, wherein the step (d) is to immerse the porous aluminum oxide template into which the nanotubes are inserted in a mixed solution of ethanol, water, and sodium hydroxide. . Composite using silicon oxide nanotubes having the functional group of claim 1. The complex according to claim 10, wherein the complex is a reaction between a silicon nanotube having a functional group and a gold substrate.

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