KR20080107866A

KR20080107866A - Process for producing of high functional hollow titania nano particle with poly methyl methacrylate

Info

Publication number: KR20080107866A
Application number: KR1020070056191A
Authority: KR
Inventors: 권용구; 오주현
Original assignee: 인하대학교 산학협력단
Priority date: 2007-06-08
Filing date: 2007-06-08
Publication date: 2008-12-11

Abstract

The present invention relates to hollow titania nanoparticles prepared by depositing a titania precursor on the surface of monodisperse polymethylmethacrylate nanoparticles prepared by emulsion polymerization of methyl methacrylate, and then calcining the polymer core. .

Description

Process for producing of high functional hollow titania nanoparticles with poly methyl methacrylate

1 is a view schematically showing a method for producing a high-functional hollow titania nanoparticles of the present invention.

2A and 2B are photographs showing scanning electron microscope (SEM) photographed images before and after calcination of the hollow titania nanoparticles of the present invention, respectively.

3A and 3B are photographs showing transmission electron microscope (TEM) images before and after calcination of the hollow titania nanoparticles of the present invention, respectively.

The present invention relates to high-functional titania nanoparticles using polymethyl methacrylate (hereinafter referred to as "PMMA") nanoparticles and a method of manufacturing the same. Specifically, a hollow titania nanoparticle wall prepared by introducing an amine group into PMMA nanoparticles through aminolysis to PMMA nanoparticles having a positive charge to further improve the surface charge of the PMMA nanoparticles. It relates to a manufacturing method that can increase the density and uniformity of the.

Generally, titania nanoparticles are used in solar cells, secondary batteries, photocatalysts and display electronics industries. In the solar cell field, titania is mainly used in dye-sensitized solar cells, which have recently been spotlighted at low cost and high efficiency. This dye-sensitized solar cell is composed of photoelectrode, counter electrode, dye fixture and electrolyte. As an inorganic material used as a photoelectrode and a dye fixing material of a dye-sensitized solar cell, titania (TiO ₂ ), ZnO, SnO _2, and the like have been studied. Among them, titania is most used because of its high efficiency. Titania for dyestuff fixtures are nanoparticles ranging from tens of nanometers to hundreds of nanometers, and dyes are immobilized on the surface of the titania to accept electrons.

In the photocatalyst field, Titania absorbs ultraviolet rays and generates electrons and holes when it receives light. Since electrons and holes generated by UV absorption in Titania have very strong reducing and oxidizing powers, various chemicals in the air, such as harmful chemicals and odorous substances dissolved in water, are decomposed, harmless, and decomposed in various fields. You can do

Because of this usefulness, the production of titania particles is actively made and used. The production of titania nanoparticles is largely made using oxidation method of titanium tetrachloride (TiCl ₄ ) or hydrolysis and firing method of titanium sulfate (TiSO ₄ ), titanium alkoxide reaction, precipitation method of titanium hydroxide, Pyrolysis of titanium citrate precursors is also made (M. Vallet-Regi, J. Pena, A. Martinez and JM Gonezalez-Calbet, J. Mater. Res. 8, 2336, 1993). Recently, there have been examples of preparing titania particles using spray and aerosol methods, and manufacturing titania nanoparticles using RF plasma (YS Yoon and IH Jung, J. Korean Ind. Eng. Chem. 13, 754, 2002.). There is an example.

However, most of the titania nanoparticles used as photocatalyst materials or solar cell materials are filled with particles. Therefore, the surface area of the titania nanoparticles is small, so that the amount of dye molecules that can be fixed is small, thereby reducing the efficiency of the solar cell. Similarly, the titania nanoparticles filled with the inside of the particles have a small surface area, which reduces the efficiency as a photocatalyst.

Due to this problem, Korean Patent Publication No. 10-2005-0042763 discloses an example in which hollow titania particles are manufactured in order to increase the surface area of the titania particles, and a hollow titania particle is manufactured using polystyrene nanoparticles.

However, conventional hollow titania nanoparticles use polymer particles without charge and 2,2-azobis (2-methylpropionamidine) dihydrochloride when coating the titania precursor onto the polymer nanoparticles. Since the charge was induced, there was a problem that the uniformity and the density of the walls of the hollow titania nanoparticles were decreased because the strength of the charge was not large.

In order to overcome this problem, the present inventors have used styrene monomer as a framework for titania nanoparticles in Korean Patent No. 661662. However, the present inventors have studied to produce titania nanoparticles with improved wall uniformity and density, and when compared to the case of using styrene, the ammonia decomposition reaction of PMMA nanoparticles results in a more dense and uniform surface with increased surface charge of the particles. It was found that one nanoparticle could be obtained and completed the present invention.

In order to solve the problems of the prior art as described above, the present invention uses the PMMA nanoparticles having higher surface charges by bonding the groups having amine bonds to the PMMA nanoparticles having charges, and thus the uniformity and density of the walls are high. Another object of the present invention is to provide a hollow hollow titania particle having a hollow interior and a manufacturing method thereof.

It is another object of the present invention to manufacture hollow titania nanoparticles to speed up particle movement in a fluid, thereby making hollow titania nanos that can be used in solar cells, secondary batteries, photocatalysts and electrophoretic displays. It is an object to provide a method for producing particles. For example, it is an object of the present invention to provide a method for manufacturing hollow titania nanoparticles that can be significantly improved in use in the e-paper display industry and the color e-paper display industry.

In order to achieve the above object, the hollow titania nanoparticles of the present invention comprises the steps of preparing a monodisperse PMMA nanoparticles are charged; Performing a amine decomposition reaction on the PMMA nanoparticles; Preparing organic-inorganic nanoparticles by depositing a titania precursor onto a surface by using PMMA nanoparticles having an amine group introduced therein as a template by the amine decomposition reaction; And by calcining the organic-inorganic nanoparticles can be prepared by a method comprising the step of removing the polymer core.

According to a preferred embodiment of the present invention, in the method for producing hollow titania nanoparticles, the framework of the nanoparticles in which the titania is deposited is a monodisperse polymethyl methacrylate nanoparticle prepared by emulsion polymerization of methyl methacrylate. Can be.

According to another suitable embodiment of the present invention, the monodisperse polymethylmethacrylate nanoparticles may react with hexamethylenediamine, whereby an amine bond-containing group may be bound to the particle surface.

According to another suitable embodiment of the present invention, the monodisperse polymethyl methacrylate nanoparticles are preferably 170-200 nm in size.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Hollow titania nanoparticles of the present invention comprises the steps of preparing a monodisperse PMMA nanoparticles having a charge; Performing a amine decomposition reaction on the PMMA nanoparticles; Preparing organic-inorganic nanoparticles by depositing a titania precursor onto a surface by using PMMA nanoparticles having an amine group introduced therein as a template by the amine decomposition reaction; And calcining the organic-inorganic nanoparticles to remove the polymer core. 1 is a view schematically showing a method for producing a high-functional hollow titania nanoparticles of the present invention, I in Figure 1 shows a monodisperse polymer colloidal nanoparticles, ie PMMA nanoparticles prepared according to the present invention, II The titania precursor is deposited around the PMMA nanoparticles, and III represents the hollow titania nanoparticles of the present invention, which are calcined to remove the polymer nanocores.

Monodisperse PMMA nanoparticles are prepared by addition and polymerization of an ionic initiator, monomer, ionic monomer and crosslinking agent, followed by lyophilization. In this case, the polymerization may use an emulsion polymerization method in which no surfactant is added. 2,2'-azobis (2-methylpropionamidine) dihydrochloride (hereinafter abbreviated as "AIBA") as an ionic initiator, methyl methacrylate (hereinafter abbreviated as "MMA") as a monomer, [2- (methacyloxy) ethyl] trimethylammonium chloride (hereinafter abbreviated as "MOTAC") was used as the ionic monomer, and ethylene glycol dimethacrylate (hereinafter abbreviated as "EGDMA") was used as a crosslinking agent. .

The monodisperse polymer colloidal nanoparticles may be uniformly produced in different sizes of about 30 nm to 500 nm depending on the amount of the ionic monomer added. Therefore, the amount of ionic monomer added is adjusted according to the desired particle size. Although the addition amount of MOTAC which is an ionic monomer in this invention is not specifically limited, It is preferable to use in the range of 0.1-1 g.

In the polymerization conditions, the polymerization time is 10-14 hours, preferably 12 hours, and the polymerization temperature is 60-80 ° C, preferably 70 ° C.

PMMA nanoparticles prepared by the polymerization is subjected to a amine decomposition reaction with hexamethylenediamine as shown in the following Equation 1. When the amine decomposition reaction is carried out, a group having an amine bond is introduced to the PMMA nanoparticles, and the positive charge on the surface of the prepared PMMA nanoparticles is higher. The high charge on the surface of the polymer particles increases the uniformity and the density of the particles, thereby increasing the uniformity and the density of the walls of the resulting hollow nanoparticles.

[Equation 1]

Next, using the prepared monodisperse polymer colloidal nanoparticles as a template, a titania precursor is deposited on the surface of the polymer to prepare organic-inorganic nanoparticles. The structure of the titania precursor used in the present invention is an anatase type, and the titanium butoxide is dissolved in an ethanol solution containing a stabilizer. The titania precursor is uniformly deposited to a thickness of 25 nm to 35 nm on the surface of the monodisperse polymer colloidal nanoparticles through hydrolysis and condensation reaction as shown in the following structural formula.

[Formula]

The organic-inorganic nanoparticles on which the Taatania particles are deposited are dried. The core of the obtained organic-inorganic nanoparticles is subjected to primary heat treatment at a temperature of 70-90 ° C. for 1-3 hours. After the second heat treatment for 1-3 hours at a temperature of 220-260 ℃, it is calcined at a temperature of 500 to 800 ℃ to remove the polymer core (core) to produce monodisperse hollow titania nanoparticles. As shown in FIGS. 2A and 2B, before and after calcination of the titania nanoparticles of the present invention, images taken by scanning microscope show that the specific surface area of the titania nanoparticles after calcination becomes larger and the particle size becomes more uniform. It can be seen that.

Although the present invention will be described in more detail with reference to Examples, the present invention is not limited to these Examples.

The present invention was carried out as shown in Table 1 below.

Table 1

Execution condition Example 1 Example 2 Example 3 Example 4 MMA (g) 10 10 10 10 EGDMA (g) One One One One MOTAC (g) One 0.2 0.16 0.1 AIBA (g) 0.25 0.25 0.25 0.25 H ₂ O (ml) 100 100 100 100 Polymerization time (h) 12 11 13 12 Temperature (℃) 70 70 80 70 PMMA nanoparticle size (nm) 190 140 174 202

Example 1

0.25 g of AIBA as an ionic initiator, 10 g of PMMA as a monomer, 100 ml of water, 1 g of [2- (methacyloxy) ethyl] trimethylammonium chloride (hereinafter abbreviated as MOTAC) as an ionic monomer, and 1 g of EGDMA as a crosslinking agent were added thereto. Polymerized. The polymerization temperature was 70 ° C., the stirring speed was 700 rpm, and the polymerization time was 12 hours. The prepared polymer nanoparticles were lyophilized to obtain polymer nanoparticles. The particle size obtained was 190 nm. The obtained PMMA nanoparticles and hexamethylenediamine were reacted in the presence of water. The polymer nanoparticles bonded with the amine group were added to the ethanol solution with poly (vinylpyrrolidone) as a stabilizer and stirred. Thereafter, titanium butoxide was dissolved in an ethanol solution to prepare a titanium precursor, which was mixed with a solution containing the polymer nanoparticles. The prepared organic-inorganic nanoparticles were dried, first heat treated at 80 ° C. for 1 hour, and second heat treated at 240 ° C. It was calcined again at a temperature of 500-800 ° C. to remove the polymer core to obtain monodisperse hollow titania nanoparticles.

Example 2

It carried out similarly to Example 1 on the basis of the polymerization conditions of Table 1, setting MOTAC amount to 0.2g.

Example 3

MOTAC amount was 0.16g, and it carried out similarly to Example 1 on the conditions of polymerization of Table 1.

Example 4

It carried out similarly to Example 1, with the amount of MOTAC being 0.1g, and the polymerization conditions of Table 1.

The present invention can improve the density and uniformity of the prepared particles by increasing the intensity of the surface charge of the polymer nanoparticles by bonding the amine group to the PMMA nanoparticles. Using PMMA nanoparticle frameworks with increased surface charge strength, the titania particles are strongly deposited, increasing the uniformity and density of the walls of the hollow titania particles.

Monodisperse hollow titania nanoparticles of the present invention can be used as a solar cell, a secondary battery, a photocatalyst because the specific surface area and the size of the particles are uniform than conventional nanoparticles filled inside. The efficiency is also superior to that of the conventional nanoparticles filled with the inside. In addition, because the hollow particles are fast moving speed of the particles in the fluid compared to the existing titania filled particles, the response speed can be significantly improved when applied to the display industry, electrophoretic display (e-paper) It can be usefully used for panels.

Claims

In the manufacturing method of hollow titania nanoparticles,

The method of manufacturing hollow titania nanoparticles, characterized in that the framework of the nanoparticles on which titania is deposited is monodisperse polymethyl methacrylate nanoparticles prepared by emulsion polymerizing methyl methacrylate.

The method of claim 1, wherein the monodisperse polymethylmethacrylate nanoparticles react with hexamethylenediamine to bond an amine bond-containing group to the surface of the nanoparticles.

The method of claim 1, wherein the monodisperse polymethyl methacrylate nanoparticles have a size

Method for producing hollow titania nanoparticles, characterized in that 170-200nm.