KR101019747B1 - Method for preparing gold / titanium oxide composite nanostructure using self-assembled biblock copolymer and two-dimensional arrayed gold / titanium oxide nano dots and nanowires prepared accordingly - Google Patents

Abstract

The present invention relates to a method for preparing a gold / titanium oxide composite nanostructure using a self-assembled biblock copolymer, and to a two-dimensional arrayed gold / titanium oxide nano dot and a nanowire manufactured according to the present invention. By controlling the mixing ratio of the block copolymer, the gold nanoparticles and the titanium oxide precursor solution, the gold / titanium oxide composite nano nanoparticles and irregular nanowires are regularly produced by two-dimensionally arranged gold / titanium oxide composite nano Since the material can be arranged, it can be usefully used in industrial fields requiring gold nanoparticles / titanium oxide composite nanomaterials.

Gold / titanium oxide, nanoparticles, hybrids, nanodots, nanowires, self-assembly technology, block copolymers, two-dimensional array

Description

Method for preparing gold / titanium oxide composite nanostructures using self-assembled biblock copolymers and two-dimensional arrayed gold / titanium oxide nanodots and nanowires prepared accordingly diblock copolymer and 2D arrays of Au / titania nanodot / nanowire}

The present invention relates to a method for preparing a gold / titanium oxide composite nanostructure using a self-assembled biblock copolymer, and to two-dimensional arrayed gold / titanium oxide nanodots and nanowires prepared accordingly.

Self-assembly technology has recently been in the spotlight as a tool for manufacturing nanoscale devices such as medical, electronic / information, optics, and sensors. For example, two-dimensional or three-dimensional assemblies of monodisperse nanoparticles are used in functional coatings, dye-free paints, and the like, and for templates, light splitting, optical filters, and photonic crystals for the growth of arrayed micro or nanoporous materials. It has been utilized in optical material and device applications.

Block copolymers tend to phase-separate each block into their respective domains due to the covalent bonds between the two blocks in the form of two or more polymer chains covalently linked. Such a block copolymer can form a periodic nanostructure having a size of about 10 nm to 100 nm by spontaneous phase separation, the shape and size of the nanostructure is the molecular weight of the block copolymer, the volume ratio of each block, It is determined by the Flory-Huggins interaction coefficient between each block, and further, by dissolving in a solvent selective to one block, spontaneous and cylindrical micelles of spontaneous size can be spontaneously formed.

Using the self-assembly of the block copolymer as described above, the size of the particles in the nanostructure of the block copolymer can be limited to nanometer size without any treatment, the arrangement of the particles also the size and spacing in the nanostructure Limited by the size and arrangement of the particles.

Titanium oxide has three crystal structures such as rutile, anatase, and brookite. Among them, rutile has high refractive index, hardness, and dielectric constant. It is mainly used for industrial, paint white pigments, cosmetics, and food additives. Anatase has excellent stability at low temperatures and is widely used as a photocatalyst, and brookite is found only in natural minerals. Titanium oxide is harmless to human body and is widely used in paint, printing ink, plastic, paper, synthetic fiber, rubber, capacitor, crayon, electric and electronic device.

On the other hand, composite materials composed of metal / semiconductor heterogeneous components are rapidly increasing in interest due to their excellent physical properties. Especially, hybrid gold / titanium oxide in which gold is introduced into titanium oxide is due to the induction effect of surface plasmon properties of the gold component. It is known to express improved properties that monocomponent titanium oxide does not have, and can be widely used in multicolored light emitting materials, photocatalysts, sensors, and the like.

The production method of the gold / titanium oxide is an ion implantation method, sputtering, sol-gel process, photoreduction reaction method, etc., most of the expensive equipment or complicated multi-step process is adopted is not advantageous in terms of economics. In addition, when manufacturing the multi-component particles have a disadvantage in that the uniformity of the components in the particles, and difficult to control in the form of the particles.

On the other hand, the sol-gel method, which is a liquid phase method, is capable of mixing and preparing raw materials at the molecular level, thereby increasing uniformity of the prepared particles, preparing particles having a large surface area, and lowering the sintering temperature. It has been widely used in the preparation of multicomponent composites. In particular, the sol-gel method using a high-purity alkoxide hydrolysis has a wide application range, there is an advantage that the final product can be produced in various forms such as powder, monolith and fiber form.

Therefore, the present inventors prepared a gold / titanium oxide composite nanostructure by using a self-assembled biblock copolymer and a sol-gel process. In particular, gold nanoparticles were added to the diblock copolymer / titanium oxide precursor solution in various mixing ratios to find a method for preparing a structure having another two-dimensional array form in the form of nanodots or nanowires, thereby completing the present invention.

The present invention provides a method for preparing a gold / titanium oxide composite nanostructure using a self-assembling diblock copolymer.

Another object of the present invention is to provide a two-dimensional arrayed gold / titanium oxide nano dots and nanowires prepared by the above method.

The present invention provides a method for producing a gold / titanium oxide composite nanostructure using a self-assembling diblock copolymer.

The present invention provides two-dimensional arrayed gold / titanium oxide nanodots and nanowires thus prepared.

According to the present invention, by controlling the mixing ratio of the self-assembly biblock copolymer, gold nanoparticles and titanium oxide precursor solution to prepare a two-dimensionally arranged gold / titanium oxide nano-dots and irregular nanowires to avoid the conventional complex process Without being able to arrange the gold / titanium oxide composite nano material, it can be usefully used in the industrial field that requires gold nanoparticles / titanium oxide composite nano material.

Hereinafter, the present invention will be described in detail.

Dissolving the self-assembled copolymer in a solvent to prepare a micelle solution (step 1); Dissolving gold nanoparticles in a solvent to prepare a colloidal solution (step 2); Preparing a titanium oxide sol-gel precursor solution (step 3); After mixing the micelle solution prepared in step 1, the colloidal solution prepared in step 2, and the sol-gel precursor solution prepared in step 3 at a predetermined ratio, spin coating the substrate to form gold nanoparticles / titanium oxide / self assembly Preparing a copolymer thin film (step 4); And removing the self-assembled copolymer by irradiating ultraviolet rays to the thin film prepared in step 4 (step 5).

Hereinafter, the present invention will be described in detail step by step.

First, step 1 according to the present invention is a step of preparing a micelle solution by dissolving the self-assembled copolymer in a solvent.

The self-assembled copolymer is a diblock copolymer and can be dissolved in an optional solvent in only one block to form a micelle in a solution. At this time, the self-assembled copolymer according to the present invention is preferably poly (styrene-block-ethylene oxide) (Poly (styrene-b-ethylene oxide, PS-b-PEO), and the solvent is used in the styrene block of the copolymer. It is preferable, but not limited to, to prepare micelle solutions using selective toluene, chloroform, dimethylformamide (DMF, dimethylformamide) or benzene.

Furthermore, the micelle solution of step 1 may contain 0.1 to 1% by weight of the self-assembly copolymer. If the self-assembled copolymer is less than 0.1% by weight, the titanium oxide nanoparticles are not arranged so that the composite nanostructure is not formed. If the self-assembly copolymer is more than 1.0% by weight, the monomolecular micelle is formed during the thin film formation by spin coating. The problem is that you can't get an array.

Next, step 2 according to the present invention is a step of preparing a colloidal solution by dissolving gold nanoparticles in a solvent.

The gold nanoparticles of step 2 are gold tetrachloro hydrate (HAuCl ₄ 6H ₂ O), lithium gold chlorine compound (lithium gold tetrachloro hydrate, LiAuCl ₄ ), or gold nanoparticles modified with a hydrophilic ligand as a precursor As the solvent, water, tetrahydrofuran (THF, Tetrahydrofuran) or chloroform may be used. The surface of the dissolved gold nanoparticles may be treated with 4-mercaptophenol (4-mercaptophenol) to be made of hydrophilic gold nanoparticles having a hydroxyl group, the gold nanoparticles are selective to the polyethylene oxide portion of the hydrophilic portion Can be combined.

In this case, the colloidal solution may dissolve the gold nanoparticle precursor in a concentration of 0.1 to 1% by weight with respect to the solvent. If the concentration is less than 0.1% by weight, there is a problem that gold nanoparticle clusters are not obtained, and if the concentration is more than 1% by weight, there is a problem of being precipitated without dissolving during mixing with the block copolymer.

Step 3 according to the present invention is a step of preparing a titanium oxide sol-gel precursor solution. The sol-gel precursor solution may be prepared by dissolving the titanium oxide precursor in a solvent, followed by dilution and stirring by adding a strong acid. The titanium oxide precursor may be titanium alkoxide such as titanium tetra-isopropoxide (TTIP) or titanium tetrabutoxide, and the solvent may be ethanol or isopropanol. Can be used.

The strong acid opens or recesses the polyethylene oxide block portion of the copolymer of step 1, and simultaneously hydrolyzes the titanium oxide precursor to form a dense titanium oxide nanostructure on the opened or recessed polyethylene oxide portion. At this time, the strong acid is preferably concentrated hydrochloric acid, but is not limited thereto.

In step 4 according to the present invention, after mixing the micelle solution prepared in step 1, the colloidal solution prepared in step 2, and the sol-gel precursor solution prepared in step 3 in a predetermined mixing ratio, spin coating the substrate. To prepare a gold nanoparticles / titanium oxide / magnetic assembly copolymer thin film.

The mixing of step 4 is preferably mixed so that the gold nanoparticles in the colloidal solution of step 2 with respect to the polyethylene oxide in the micelle solution of step 1 is 0.1 ~ 0.5 in a molar ratio (Au / EO).

When the gold nanoparticles in the colloidal solution of step 2 with respect to the polyethylene oxide in the micelle solution of step 1 has a molar ratio of less than 0.1, the dispersion of gold nanoparticles in each micelle is not uniform. There is a problem in that the gold nanoparticles are not included and combine to form agglomerates.

In the mixing of the step 4, it is preferable to mix the sol-gel precursor solution of the step 3 to 3% to 50% by weight relative to the micelle solution of the step 1.

As the ratio of the titanium oxide sol-gel precursor solution to the micelle solution increases, a complex nanostructure of gold / titanium oxide arranged in two dimensions may be formed to be recessed or protruded on the surface thereof, and the mixing ratio is represented by weight. If it is outside 3 to 50%, the gold / titanium oxide composite nanostructure cannot be obtained in a regular two-dimensional array form, or the gold / titanium oxide composite precursor escapes the self-assembled copolymer template and aggregates with neighboring composite precursors to form agglomerates. There is a problem.

The present invention also provides gold / titanium oxide nanodots and nanowires arranged in two dimensions.

The two-dimensionally arranged gold / titanium oxide nanodots and nanowires prepared according to the present invention may form nanodots or nanowires by controlling the ratio of the micelle solution, colloidal solution, and titanium oxide sol-gel precursor solution. It can be produced by a simplified method than the process for forming conventional nano-dots and nanowires.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are merely to illustrate the invention, the content of the present invention is not limited by the following examples.

Example 1 Preparation of Gold / Titanium Oxide Composite Nanostructure 1

Step 1. Preparation of micelle solution comprising self-assembled copolymer

Poly (styrene-block-ethylene oxide), PS-b-PEO (M _{n, ps} = 19 000 g / mol, M _{n , peo} = 6 400 g / mol) was dissolved in toluene at a concentration of 1.0% by weight to prepare a micelle solution.

Step 2. Preparation of a Colloidal Solution Containing Gold Nanoparticle Precursors

Gold nanoparticle precursor was dissolved in gold tetrachloride (HAuCl ₄ · 6H ₂ O) in isopropanol (isopropanol) at a concentration of 1.0% by weight to prepare a colloidal solution.

Step 3. Preparation of titanium oxide sol-gel precursor solution

To 2.5 ml of isopropanol in which 0.37 g of titanium tetra-isopropoxide (Aldrich) was dissolved, 0.12 g of concentrated hydrochloric acid (37%) was added and diluted with 2.3 ml of toluene to prepare a sol-gel precursor solution.

Step 4. Preparation of Gold Nanoparticle / Titanium Oxide / Self-Assembly Copolymer Thin Film

The gold nanoparticle precursor solution of step 2 was mixed with the micelle solution of step 1 such that the molar ratio of the gold nanoparticle precursor was 0.2 with respect to the polyethylene oxide block included in the micelle solution. The titanium oxide sol-gel precursor solution of step 3 was mixed at a rate of 3.5% by weight with respect to the micelle solution of step 1. The mixed solution of the micelle solution, the gold nanoparticle solution and the sol-gel precursor solution was stirred for 30 minutes, and then added to the silicon substrate and spin-coated at 2000 rpm for 60 seconds to form the gold nanoparticle / titanium oxide / self-assembled copolymer. A thin film was prepared.

Step 5. Removal of Self-Assembly Copolymers by Ultraviolet Irradiation

Ultraviolet rays having a wavelength of 254 nm were irradiated to the thin film of step 4 for about 12 hours under an energy intensity condition of about 25 J / cm ² to remove the self-assembled copolymer.

Example 2 Preparation of Gold / Titanium Oxide Composite Nanostructure 2

In the step 4, it was prepared in the same manner as in Example 1 except for mixing the titanium oxide sol-gel precursor solution of step 3 to 11.6% by weight relative to the micelle solution of step 1.

Example 3 Preparation of Gold / Titanium Oxide Composite Nanostructure 3

In the step 4, it was prepared in the same manner as in Example 1 except for mixing the titanium oxide sol-gel precursor solution of step 3 to 23.1% by weight relative to the micelle solution of step 1.

Example 4 Preparation of Gold / Titanium Oxide Composite Nanostructure 4

In Step 4, was prepared in the same manner as in Example 1 except for mixing the titanium oxide sol-gel precursor solution of step 3 to 46.2% by weight relative to the micelle solution of step 1.

Example 5 Preparation of Gold / Titanium Oxide Composite Nanostructure 5

The gold nanoparticle precursor solution of step 2 was prepared as a 2.0 wt% colloidal solution, and in step 4, the molar ratio of the gold nanoparticle precursor to the polyethylene oxide block in which the 2.0 wt% concentration colloidal solution is included in the micelle solution was added. The same procedure as in Example 3 was conducted except that the mixture was adjusted to 0.2.

Example 6 Preparation of Gold / Titanium Oxide Composite Nanostructure 6

The 2.0 wt% colloidal solution in step 4 was performed in the same manner as in Example 5, except that the molar ratio of the gold nanoparticle precursor was 0.3 with respect to the polyethylene oxide block included in the micelle solution.

Example 7 Preparation of Gold / Titanium Oxide Composite Nanostructure 7

The 2.0 wt% colloidal solution in step 4 was performed in the same manner as in Example 5, except that the molar ratio of the gold nanoparticle precursor was 0.4 to the polyethylene oxide block included in the micelle solution.

Experimental Example 1 Structural Changes of Composite Nanostructures of Gold Nanoparticles / Titanium Oxide / Self-Assembly Copolymer Template According to Titanium Oxide Content

In the mixed solution of step 4, in order to determine the structural change of the multi-component composite nanostructure according to the change in the ratio of the titanium oxide precursor to the self-assembled copolymer, the surface before the ultraviolet irradiation of Examples 1 to 4 Was observed in atomic force microscopy (AFM) and is shown in FIG.

As shown in FIG. 1, Examples 1 to 4 were formed with nano-dots having a diameter of about 30 nm, and furthermore, Example 1 and 11.6 wt%, wherein the ratio of the titanium oxide precursor solution to the micelle solution was 3.5 wt%. In Example 2, it was observed that the nano-dots are in a depressed form, and in Example 3 and 46.2 wt% of the titanium oxide precursor solution 23.1 wt% with respect to the micelle solution, the nano-dots protruded. It was confirmed that, as the solution content of the titanium oxide precursor increases, it forms a protruding nanospot.

Experimental Example 2 Structural Changes of Gold Nanoparticles / Titanium Oxide Composite Nano Structures According to Titanium Oxide Precursor Concentration

In the mixed solution of step 4, in order to determine the structural change of the multi-component composite nanostructure according to the ratio of the titanium oxide precursor to the self-assembly copolymer, the surface after the ultraviolet irradiation of Examples 1 to 4 Was observed in atomic force microscopy (AFM) is shown in Figure 2.

As shown in FIG. 2, Examples 1 to 4 produced high-density gold / titanium oxide nanoparticles from which the self-assembled copolymer was removed after UV irradiation. Specifically, Example 1 (Fig. 2 (a)) was confirmed that the nano-dots of 5 nm to 30 nm are arranged in two dimensions, Example 2 (Fig. 2) in which the content of the titanium oxide precursor increased to 11.6% by weight In (b)), it was confirmed that about 2 to 10 connected nano-dots or nanowires were arranged two-dimensionally in the order of 5 to 30 nm of the arranged nano-points observed in Example 1, and the titanium oxide precursor content was 23.1 weight. In Example 3 (Fig. 2 (c)) to Example 4 (Fig. 2 (d)) increased to 46.2% by weight and it was confirmed that the nano-dots form a nanowire constantly connected in two dimensions.

Experimental Example 3 Observation of Distribution of Gold Nanoparticles and Titanium Oxide in Gold Nanoparticles / Titanium Oxide / Self-Assembly Copolymer Composite Nanostructures

In order to examine the internal structure of the gold nanoparticles / titanium oxide / self-assembled copolymer composite nanostructure, the surface before the ultraviolet irradiation of the thin film prepared according to Example 5 was observed by a transmission electron microscope (TEM) in FIG. Indicated.

As shown in FIG. 3 (a), the part shown as the black region is a polyethylene oxide domain in which high-density gold nanoparticles / titanium oxide are distributed, and it is confirmed that domains of 20 to 30 nm are uniformly arranged throughout.

FIG. 3 (b) is an enlarged view of FIG. 3 (a). The black portion is a polyethylene oxide region in which gold nanoparticles and the gray region are uniformly distributed in titanium oxide, and the bright portion is a polystyrene region. As shown in FIG. 3 (b), it was confirmed that gold nanoparticles having a size of 1 to 5 nm were uniformly distributed in the titanium oxide / polyethylene oxide domain.

Experimental Example 4 Structure Change of Gold Nanoparticles / Titanium Oxide Composite Nano Structures According to Gold Nanoparticle Concentration

The structural change of the gold nanoparticles / titanium oxide composite nanostructure according to the change in the molar ratio (Au / EO) of the gold nanoparticle precursor to the polyethylene oxide block of the micelle solution of step 1 in the mixed solution of step 4 In order to find out, the surface of the composite nanospheres prepared according to Examples 5, 6 and 7 were observed with a transmission electron microscope (TEM) and shown in FIG. 4.

As shown in FIG. 4, in Example 5 (FIG. 4 (a)) in which the molar ratio (Au / EO) of the gold nanoparticle precursor solution to the polyethylene oxide block included in the micelle solution was 0.2, it is mainly 5 to 30 nm. Although nano dots were observed, in Example 6 (FIG. 4 (b)) in which the molar ratio of the gold nanoparticle precursor solution was increased to 0.3, not only nano dots but also nanowire morphologies were simultaneously observed. Furthermore, Example 7 (FIG. 4C), in which the molar ratio of the gold nanoparticle precursor solution was increased to 0.4, was longer than that of Example 6, and more pronounced nanowires were observed to increase as the molar ratio of the gold nanoparticle precursor solution increased. It was confirmed that many nanowires were formed.

FIG. 4 (d) is a photograph of Example 7 observed at high magnification. As shown in FIG. 4 (d), the nanowires formed in Example 7 are polyethylene oxide domains including high density gold / titanium oxide. It was confirmed that the gold nanoparticles having a size of 1 to 5 nm are uniformly distributed in the inside.

1 is an atomic force microscope (AFM) photograph of one embodiment prepared according to the present invention ((a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4):

Figure 2 is an electron scanning microscope (SEM) photograph of one embodiment prepared according to the present invention ((a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4) :

3 is a transmission electron microscope (TEM) photograph of one embodiment made according to the present invention ((a) Example 5, (b) High magnification photographs of Example 5); And

4 is a transmission electron micrograph of one embodiment prepared according to the present invention ((a) Example 5, (b) Example 6, (c) Example 7, (d) High magnification photograph of Example 7) .

Claims (12)

The self-assembly copolymer poly (styrene-block-ethylene oxide) was dissolved at a concentration of 0.1 to 1% by weight in a solvent selected from the group consisting of toluene, chloroform, dimethylformamide (DMF, Dimethylformamide), and benzene to dissolve the micelle solution. Manufacturing step (step 1); Preparing a colloidal solution by dissolving a hydrophilic gold nanoparticle having a hydroxyl group in a solvent selected from the group consisting of water, tetrahydrofuran (THF, Tetrahydrofuran), chloroform and isopropanol (step 2); Preparing a titanium oxide sol-gel precursor solution (step 3); Mixing the micelle solution prepared in step 1, the colloidal solution prepared in step 2 and the sol-gel precursor solution prepared in step 3 in a predetermined ratio, the step 2 for the polyethylene oxide in the micelle solution of step 1 Of the gold nanoparticles in the colloidal solution of 0.2 to 0.5 in a molar ratio (Au / EO), and the sol-gel precursor solution of the step 3 to 23.1% to 50% by weight relative to the micelle solution of step 1 After mixing, spin coating the mixture onto a substrate to prepare a gold nanoparticle / titanium oxide / self-assembled copolymer thin film (step 4); And Method for producing a gold / titanium oxide composite nanowires arranged in two dimensions comprising the step (step 5) of removing the self-assembly copolymer by irradiating UV light to the thin film prepared in step 4. delete delete delete delete delete The method of claim 1, wherein the precursor of the gold nanoparticles is any one selected from the group consisting of gold tetrachloro hydrate (HAuCl ₄ 6H ₂ O) and lithium gold tetrachloro hydrate (LiAuCl ₄ ). Method for producing a gold / titanium oxide composite nanowires arranged in two dimensions. The method of claim 1, wherein the gold nanoparticle precursor content in the colloidal solution of step 1 is 0.1 to 3% by weight. The method of claim 1, wherein the titanium oxide sol-gel precursor solution of step 3 consists of titanium tetra-isopropoxide (TTPI), titanium tetrabutoxide and titanium alkoxide A method for producing a two-dimensionally arranged gold / titanium oxide composite nanowires, which is prepared by dissolving any one of the titanium oxide precursors selected from the group in the solvent used in step 2. delete delete 10. A two-dimensionally arranged gold / titanium oxide nanowire made by the method of any one of claims 1 and 7-9.

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