KR100795480B1 - Method for the Preparation of Gold Nanoparticles - Google Patents

Abstract

The present invention relates to a method for producing gold nanoparticles. More specifically, the production of gold nanoparticles well dispersed in a uniform shape and size using a nonionic surfactant without a separate reducing agent and / or supply of external energy, and by changing the reaction conditions to change the size of the gold nanoparticles It relates to a method for producing gold nanoparticles that can be controlled.

In the method for producing gold nanoparticles, the gold salt is mixed with an aqueous solution containing a nonionic surfactant to react to form gold nanoparticles, and the concentration of the gold salt and / or the nonionic By controlling the concentration of the surfactant, and / or the reaction temperature, there is provided a method for producing gold nanoparticles, characterized in that to control the particle size of the gold nanoparticles.

According to the present invention, it is possible to manufacture gold nanoparticles eco-friendly and inexpensively without supplying a separate reducing agent and / or external energy, and to efficiently control the particle size of the gold nanoparticles by controlling reaction conditions such as concentration or temperature. It can be effective.

Gold, Nanoparticles, Nanogold, Surfactant, Gold salt

Description

Method for the Preparation of Gold Nanoparticles

1 is a diagram showing UV-Vis (ultraviolet / visible light) spectrum showing the generation state of gold nanoparticles over time in an aqueous gold salt solution added with Tween-80,

FIG. 2 shows that the concentrations of gold salt and Tween-80 are (a) 0.1 mM, 10 wt.%, (B) 0.4 mM, 10 wt.%, (C) (d) 0.1 mM, 1 wt.%, Respectively. High-resolution transmission electron microscope (HRTEM) image of the produced gold nanoparticles in

Figure 3 changes the concentration of gold salt to (a) 0.1 mM, (b) 0.2 mM, (c) 0.3 mM, (d) 0.4 mM, and the concentration of Tween-80 is 1, 3, 5, 7, 9 wt. Diagram showing the UV-Vis (ultraviolet / visible) spectrum converted to.%,

FIG. 4 shows HRTEM images and histograms showing the degree of dispersion in the size distribution of gold nanoparticles prepared using 0.4 mM gold salt and 1 wt.% Tween-80 at various temperatures.

The present invention relates to a method for producing gold nanoparticles. More specifically, the production of gold nanoparticles well dispersed in a uniform shape and size using a nonionic surfactant without a separate reducing agent and / or supply of external energy, and by changing the reaction conditions to change the size of the gold nanoparticles It relates to a method for producing gold nanoparticles that can be controlled.

Nanoparticles of metals or semiconductors have been extensively studied due to their improved electrical, magnetic, optical, and catalytic properties compared to the bulk state. Recently, considerable research is being conducted on gold nanoparticles among various metal nanoparticles. Gold nanoparticles have been used for aesthetic or therapeutic purposes since BC. Recently, research and practical use of gold nanoparticles in various applications such as catalysts, biotransmitters, electronic materials, and optical materials have been conducted. Gold nanoparticles have a wide variety of applications due to their various structures and properties, facilitating basic research and applications related to physics, chemistry, biology, and pharmacy, as well as research on other nanoparticles.

Conventionally, there are the following methods for producing gold nanoparticles.

Among the traditional methods, the Turkevitch-Frens synthesis method is a method for producing gold nanoparticles by reducing the gold chloride (HAuCl ₄ ) in water using citric acid. Following this traditional method, a two-step synthesis called a method of stabilizing gold nanoparticles using alkanethiolates and various functional thilate ligands and a rust-schiffrin method The method was introduced. In addition, there is a method of producing gold nanoparticles by reducing gold complex ions present in a gold salt solution including sodium borohydride (NaBH ₄ ) in the presence of a dendrimer.

As a physical method, there is a method using ultraviolet (UV), near infrared (Near-IR), ultrasonic waves, microwaves, or the like. Irradiation with ultraviolet or near infrared light can control the quality and size of the gold nanoparticles. In addition, a method of promoting the reduction of gold nanoparticles or controlling the size of the particles using ultrasonic waves or heat has been proposed.

As an example, Japanese Laid-Open Patent Publication No. 2005-290478 discloses a method for producing gold nanoparticles by irradiating ultrasonic waves. According to this, after adding a mixture of a precursor of gold and a dispersing aid made of a hydrate to the liquid for dispersing, finely disperses the precursor of gold in the liquid phase, and then again ultrasonically irradiates the gold It provides a method for producing gold nanoparticles to reduce the precursor to produce gold nanoparticles.

On the other hand, US Patent Publication No. 2004/0261574 discloses a method for producing gold nanoparticles, in which a gold salt aqueous solution is absorbed into an absorbent such as activated carbon or a gold absorbent resin (resin), and the gold adsorbent is screened. After the separation by ash, filtration, precipitation, etc. to make an ash state, relatively pure gold nanoparticles are prepared by removing impurities such as sodium, potassium, and calcium oxide contained in the ash with dilute acid. A method of doing this is disclosed.

However, most conventional methods for synthesizing gold nanoparticles are environmentally toxic or expensive reducing agents (sodium borohydride (NaBH ₄ ), hydrazine, hydroxylamine, sodium naphthalenide, etc.). The use of a reducing agent such as), or to supply external energy such as heat, ultraviolet rays, near infrared rays, ultrasonic waves, microwaves, or the like has been present.

In order to solve the above problems, the present invention provides a method for producing gold nanoparticles well dispersed in a uniform shape and size using a nonionic surfactant without a separate reducing agent and / or supply of external energy. The purpose.

In addition, an object of the present invention is to provide a method for producing gold nanoparticles that can control the size of the gold nanoparticles by changing only the reaction conditions without additional complicated equipment or equipment.

In order to achieve the above object, the present invention, in the method for producing gold nanoparticles, characterized in that the gold salt is mixed with an aqueous solution containing a nonionic surfactant to react to form the gold nanoparticles, the concentration of the gold salt And / or provides a method for producing gold nanoparticles, characterized in that the size of the gold nanoparticles by controlling the concentration of the non-ionic surfactant, and / or the reaction temperature. For example, the concentration of the gold salt is appropriately controlled within the range of 0.1 to 0.4 mM, and / or the concentration of the nonionic surfactant is appropriately controlled within the range of 1 to 10 wt.%, And / or the reaction temperature is 4 to 65 ° C. By appropriately controlling within the range, the size of the gold nanoparticles can be efficiently adjusted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the following will describe a preferred embodiment of the present invention, but the technical spirit of the present invention is not limited thereto, but may be variously modified and implemented by those skilled in the art.

The present invention is characterized by the production of gold nanoparticles using gold salts and nonionic surfactants. In the present invention, the size of the gold nanoparticles can be adjusted by simply changing the concentration of the surfactant or the ratio of the surfactant to the gold salt. In addition, the size of the gold nanoparticles in the present invention is characterized by being adjustable by changing the reaction temperature.

The method for producing gold nanoparticles according to the prior art uses other inhibitors or organic solvents to produce gold nanoparticles from gold salts in the presence of organic reducing agents and / or external energy. Typically a chemical or photoinduced reduction mechanism is used to express the above process. This mechanism is fundamentally different from the surfactant-inducing mechanism proposed in the present invention, which is a repeating CCO unit of a nonionic surfactant such as Tween-80 in the reaction with gold nanoparticles. Engage). However, although the specific mechanism of the present invention is not fully understood, it is understood that the long polar chain (particularly, polyethylene glycol chain) of the nonionic surfactant plays a major role in the production of gold nanoparticles.

In the present invention, considering the various capabilities of other surfactants on the molecular structure, the present invention regarding the synthesis of gold nanoparticles has been extended to other surfactants. The reaction according to the invention has shown the efficiency that the reaction is carried out at a temperature of 4 ° C. without using any other agent or external energy.

In the method for producing gold nanoparticles according to the present invention, when a non-ionic surfactant is added and reacted with an aqueous gold salt solution, the color changes from yellow to colorless and finally through pink, as is typical in the preparation of gold nanoparticles. It can be seen that red color appears.

The gold salts used in the reaction are potassium chloride (KAuCl ₄ ), sodium chlorate (NaAuCl ₄ ), gold chloride (HAuCl ₄ ), sodium bromide (NaAuBr ₄ ), gold chloride (AuCl), and gold chloride (AuCl ₃ ) , Gold bromide (AuBr ₃ ) or a combination thereof.

In addition, the nonionic surfactant may be glycerin-based fatty acid esters, sucrose-based fatty acid esters and sorbitan-based fatty acid esters, but especially sorbitan fatty acid esters (SPAN) -20 (Sorbitan monolaurate), span (SPAN) ) -40 (Sorbitan monopalmitate), Span (SPAN) -60 (Sorbitan monostearate), Span (SPAN) -80 (Sorbitan monooleate), TWEEN-20 (POE Sorbitan monolaurate), TWEEN-40 (POE One or more selected from the group consisting of Sorbitan monopalmitate, TWEEN-60 (POE Sorbitan monostearate) and TWEEN-80 (POE Sorbitan monooleate) can be used.

Referring to specific examples according to the production method of gold nanoparticles of the present invention are as follows. In a specific example, potassium chloride (KAuCl ₄ ) was used as the gold salt, and tween-80 was used as the nonionic surfactant.

Example  One

1.51 mg of potassium chlorate (KAuCl ₄ ) is added to 10 mL of a 1 wt. The solution turns from yellow to colorless over time, turns pink after about 4 hours, and finally turns red after about 6 hours, thereby producing gold nanoparticles.

FIG. 1 is a diagram showing UV-Vis (ultraviolet / visible light) spectrum showing a state of generation of gold nanoparticles over time in an aqueous gold salt solution added with Tween-80.

As can be seen in Figure 1, when the twin-80 is added to the gold salt solution, it can be seen that after a certain time gold nanoparticles are generated.

The UV-vis absorption profile depends on the size of the gold nanoparticles. More importantly, the gold nanoparticles according to the invention exhibit very stable and non-integrated properties even after several months of storage.

On the other hand, the results of the experiment confirmed that the size of the gold nanoparticles can be adjusted by changing the concentration of the nonionic surfactant or the ratio of the nonionic surfactant to the gold salt as described above. An embodiment thereof is described as follows.

Example  2

In Example 2, the size change of the gold nanoparticles was measured while changing the concentration of the Tween-80 aqueous solution and the concentration of the gold salt added thereto.

In Examples 2a and 2b, the concentrations of the gold salts added to 10 wt.% Of the Twin-80 aqueous solution at room temperature were changed to 0.1 mM and 0.4 mM, respectively. In Example 2c, 1 wt.% Of Twin-80 at room temperature was changed. The concentration of gold salt added to the aqueous solution was changed to 0.1 mM, respectively. In each case the color of the solution gradually changed from colorless to red after about 6 hours. After continuing for 11 hours, a transmission electron microscope (TEM) sample was prepared.

FIG. 2 shows that the concentrations of gold salt and Tween-80 are (a) 0.1 mM, 10 wt.%, (B) 0.4 mM, 10 wt.%, (C) (d) 0.1 mM, 1 wt.%, Respectively. It is a high-resolution transmission electron microscope (HRTEM) image of the produced gold nanoparticles.

Referring to FIG. 2, it can be seen that the size of the gold nanoparticles increases when the concentration of the gold salt is increased, and the size of the gold nanoparticles also increases when the concentration of the Tween-80 is decreased.

The size of the gold nanoparticles produced in each case is summarized in Table 1 below.

Example 2- (a) Example 2- (b) Example 2- (c) Gold salt concentration (mM) 0.1 0.4 0.1 Tween-80 Concentration (wt.%) 10 10 One Size of Gold Nanoparticles (nm) 3.02 ± 0.52 4.87 ± 1.73 5.86 ± 1.86

Table 1 shows that the size of the gold nanoparticles increases when increasing the concentration of the gold salt or decreasing the concentration of Tween-80.

Example  3

Following Example 2, several experiments were additionally performed to measure the size change of the gold nanoparticles by varying the concentration of the gold salt and the nonionic surfactant.

In Example 3, the concentration of the gold salt was changed to 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, respectively, and the concentration of the nonionic surfactant was 1 wt.%, 3 wt.%, 5 wt.%, 7 wt. % And 9 wt.%, Respectively, to determine the size change of the gold nanoparticles.

Figure 3 changes the concentration of gold salt to (a) 0.1 mM, (b) 0.2 mM, (c) 0.3 mM, (d) 0.4 mM, and the concentration of Tween-80 is 1, 3, 5, 7, 9 wt. A diagram showing the UV-vis spectrum in the state converted to.%.

In each case, gold nanoparticles were produced after a certain time. Also in Example 3, as the concentration of gold salt was increased, the size of gold nanoparticles was increased, and as the concentration of Tween-80 was increased, the size of gold nanoparticles was decreased.

Example  4

Reactions at high temperatures were also studied, but the reactions were mainly carried out at room temperature. The size of the gold nanoparticles was controllable using different temperature conditions.

FIG. 4 shows HRTEM images and histograms showing the degree of dispersion in the size distribution of gold nanoparticles prepared using 0.4 mM gold salt and 1 wt.% Tween-80 at various temperatures.

In each case of FIGS. 4A to 4, the reaction conditions and the average size of gold nanoparticles according to the reaction conditions are summarized in Table 2 below.

Example 4- (a) Example 4- (b) Example 4- (c) Example 4- (d) Gold salt concentration (mM) 0.4 0.4 0.4 0.4 Tween-80 Concentration (wt.%) One One One One Reaction temperature (℃) 4 25 45 65 Size of Gold Nanoparticles (nm) 1.48 ± 0.02 3.30 ± 0.07 10.32 ± 0.65 25.55 ± 1.45

The prepared nanoparticles showed a narrow size distribution, a good distribution in the medium, and no agglomeration. According to the above it can be seen that the size of the gold nanoparticles increases as the temperature is increased. This result can be explained as the reactivity of Tween-80 is improved as the temperature is increased. In addition, the reaction time for the formation of gold nanoparticles decreases with increasing temperature.

On the other hand, in the photograph inserted in the upper right in Figure 4a, the HRTEM image showing the periphery of the lattice of the nanoparticles shows the crystal characteristics of the nanoparticles. The Selected-Area Electron Diffraction (SAED) pattern shown in the picture inserted in the upper right of FIG. 4b clearly shows that the gold nanoparticles exhibit a face-centered cubic (FCC) structure.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, unlike the conventional method for producing gold nanoparticles, the following effects are obtained.

First, the present invention is capable of producing gold nanoparticles well dispersed at room temperature without a separate reducing agent or energy supply, and has the feature of producing gold nanoparticles using minimal equipment and materials.

Secondly, the present invention is eco-friendly and economical because it does not use toxic or expensive reactants, and thus can be usefully used in biological or biomedical applications.

Third, the present invention is capable of controlling the size of the gold nanoparticles by simply changing the reaction conditions, so that the present invention can be applied to various fields.

Fourth, the present invention is characterized by the possibility that it can be utilized in producing not only gold nanoparticles but also other metal nanoparticles.

Claims (7)

As a method for producing gold nanoparticles dispersed in a uniform shape and size without a separate reducing agent, external energy, or supply of reducing agent and external energy, A gold salt is mixed with an aqueous solution of a nonionic surfactant and reacted. The method of claim 1, 0.1-0.4 mM gold salt is mixed with an aqueous solution of 1-10 wt.% Nonionic surfactant at 4-65 ° C. for reaction. The method according to claim 1 or 2, The gold salt is potassium chloride (KAuCl ₄ ), sodium chlorate (NaAuCl ₄ ), gold chlorate (HAuCl ₄ ), sodium bromide (NaAuBr ₄ ), gold chloride (AuCl), gold chloride (AuCl ₃ ) and gold bromide ( AuBr ₃ ) is selected from the group consisting of The method according to claim 1 or 2, The nonionic surfactant is characterized in that the glycerin fatty acid ester, sucrose fatty acid ester or sorbitan fatty acid ester. The method according to claim 1 or 2, The nonionic surfactant is span (SPAN) -20 (Sorbitan monolaurate), span (SPAN) -40 (Sorbitan monopalmitate), span (SPAN) -60 (Sorbitan monostearate), span (SPAN) -80 (Sorbitan monooleate), Group consisting of TWEEN-20 (POE Sorbitan monolaurate), TWEEN-40 (POE Sorbitan monopalmitate), TWEEN-60 (POE Sorbitan monostearate) and TWEEN-80 (POE Sorbitan monooleate) Selected from The method according to claim 1 or 2, The particle size of the gold nanoparticles is characterized in that less than 50 nm. delete

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