KR101414082B1 - Treating method of particle surface and particle manufactured by the same - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a particle surface treatment method for enhancing dispersibility and particles produced thereby. More specifically, the method for surface treatment of particles according to the present invention comprises acid treating the particles, mixing the acid treated particles with a water-soluble solvent, and mixing with a surface treatment agent comprising an organic ligand. It does not require the surface treatment of silica (TEOS) or polyethylene glycol (PEG), has excellent magnetic properties, and is excellent in dispersibility even in a fat-soluble solvent, and mass production is possible.

Description

TECHNICAL FIELD [0001] The present invention relates to a particle surface treatment method, and a particle produced by the method. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a particle surface treatment method and particles produced thereby. More particularly, the present invention relates to a particle surface treatment method for improving dispersibility in polar and non-polar solvents and particles produced thereby.

Nano-sized particles with magnetism have been applied to various bio industries such as drug delivery materials and contrast agents, and display fields using the characteristics of photonic crystals. The material of the particles mainly uses iron oxide.

Since iron oxide is toxic, has low oxidation resistance and has non-hydrophilic properties, it requires a surface treatment with inorganic or organic compounds such as silica (TEOS) or polyethyleneglycol (PEG).

However, when the surface of the iron oxide particles is treated with silica (TEOS) or PEG, there arises a problem of weakening the magnetic properties of the iron oxide particles, and the dispersibility of the iron oxide particles is remarkably decreased in the oil-soluble solvent.

Further, since the surface treatment is performed under the conditions of high pressure and high temperature, there is a problem that the risk is large and it is not suitable for mass production.

Disclosure of the Invention In order to solve the above problems, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method of manufacturing a magnetic recording medium which does not require surface treatment of silica (TEOS) or polyethylene glycol (PEG), has excellent magnetic properties, The present invention provides a particle surface treatment method capable of mass production even under the conditions of

It is still another object of the present invention to provide particles produced by the above-mentioned particle surface treatment method.

According to a first aspect of the present invention, there is provided a method for treating a particle surface, comprising the steps of treating the particle with a positive charge so as to have a positive charge, mixing the acid-treated particle with a water- And mixing the hydroxide-formed particles with a surface treatment agent comprising an organic ligand that binds to the hydroxyl group.

When the particles are magnetic particles, the particles may be selected from the group consisting of Cr, Ni, Ti, Zr, Fe, Co, Zn, Gd, Ta, Nb, Pt, Au, Mg, Mn, Pd, Sr, , Mo, Sn, and Pb.

The particle may comprise a cluster of clumps of particles. The acid (acid) is hydrochloric acid (HCl), acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO _4), nitric acid (HNO _3), formic acid (Formic acid), citric acid (Citric acid), lactic acid (Lactic acid), Amino acid (Amino acid).

When a plurality of the particles are dispersed in a water-soluble solvent or a fat-soluble solvent, a steric effect may be generated between the plurality of particles by the organic ligands formed in the plurality of particles.

The surface treatment agent containing the organic ligand may be at least one selected from the group consisting of a carboxyl group, a hydroxyl group, an amine group, a vinyl group, an acrylate group, group, a ketone group, an ester group, and an aldehyde group.

The surface treatment agent containing the organic ligand may be at least one selected from the group consisting of ricinoleic acid, linoleic acid, monostearin, palmitic acid, octadecylamine, The present invention relates to a process for preparing polyolefins such as trioctylphosphine oxide, oleic acid, stearic acid, polymethylmethacrylate, polystyrene, Solbitol monooleate, The present invention relates to a method for producing a polylactic acid composition which comprises the steps of: preparing a mixture containing at least one of Sorbitan trioleate, Myristoleic acid, Palmitoleic acid, Sapienic acid, Arachidonic acid,? -Linolenic acid, At least one of Eicosapentaenoic acid, Erucic acid, Docosahexaenoic acid, Trioctylphosphate, Hexadecylamino, Fatty acid series, and Olefin series artillery Can.

According to a second aspect of the present invention, there is provided a method for producing a particle, comprising the steps of acid treating the particle so that the particle has a positive charge, mixing the acid-treated particle with a water-soluble solvent to form a hydroxyl group (-OH) And a surface treating agent comprising an organic ligand that binds the hydroxide-formed particles with the hydroxyl group.

When the particles are magnetic particles, the particles may be selected from the group consisting of Cr, Ni, Ti, Zr, Fe, Co, Zn, Gd, Ta, Nb, Pt, Au, Mg, Mn, Pd, Sr, , Mo, Sn, and Pb.

The particle may comprise a cluster of clumps of particles. The acid is hydrochloric acid (HCl), acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO _4), nitric acid (HNO _3), formic acid (Formic acid), citric acid (Citric acid), lactic acid (Lactic acid), amino acids (Amino acid ). ≪ / RTI >

When a plurality of the particles are dispersed in a water-soluble solvent or a fat-soluble solvent, a steric effect may be generated between the plurality of particles by the organic ligands formed on the plurality of particles.

The surface treatment agent containing the organic ligand may be at least one selected from the group consisting of a carboxyl group, a hydroxyl group, an amine group, a vinyl group, an acrylate group, an alcohol group A ketone group, an ester group, and an aldehyde group.

The surface treatment agent containing the organic ligand may be selected from the group consisting of ricinoleic acid, linoleic acid, monostearin, palmitic acid, octadecylamine, trioctylphosphine It is also possible to use trioctylphosphine oxide, oleic acid, stearic acid, polymethylmethacrylate, polystyrene, solbitol monooleate, sorbitan trioleate Sorbitan trioleate, Myristoleic acid, Palmitoleic acid, Sapienic acid, Arachidonic acid,? -Linolenic acid, Eicosapenta At least one of Eicosapentaenoic acid, Erucic acid, Docosahexaenoic acid, Trioctylphosphate, Hexadecylamino, Fatty acid series and olefin series can do.

The particle surface treatment method according to the present invention is excellent in dispersibility even in the oil-soluble solvent owing to the steric hindrance effect of the organic ligand while maintaining excellent magnetic properties without the surface treatment of silica (TEOS) or polyethylene glycol (PEG). In addition, there is an effect that mass production can be achieved by a simple process without high-pressure production conditions and coating of silica (TEOS) or PEG.

FIG. 1 is a flow chart of a process of a particle surface treatment method according to an embodiment of the present invention.
Fig. 2 is an image obtained by analyzing iron oxide particles of the initial iron oxide particles (black color) in Fig. 1 and (red color) after the b-step treatment using TF-IR.
FIG. 3 is an image obtained by analyzing iron oxide particles of the initial iron oxide particles (black) and (red) after the c-step treatment using TF-IR.
4 is data obtained by measuring the inter-particle dispersion according to the step a (black color), the b color (red color), and the c color (blue color) of FIG.
FIG. 5 is an image obtained by analyzing iron oxide particles of initial iron oxide particles (black) and organic ligand-treated (red) according to the second embodiment using TF-IR.
6 is data obtained by measuring the inter-particle dispersion degree produced by the second embodiment.
FIG. 7 is an image obtained by analyzing iron oxide particles of initial iron oxide particles (black) and organic ligands (red) according to the third embodiment using TF-IR.
8 is data obtained by measuring the inter-particle dispersion degree produced by the third embodiment.
FIG. 9 is an image obtained by analyzing iron oxide particles of initial iron oxide particles (black) and organic ligand (red) according to the fourth embodiment using TF-IR.
10 is data obtained by measuring the inter-particle dispersion degree produced by the fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the invention refers to the accompanying drawings that illustrate specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises ", or" having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, or combinations thereof, But do not preclude the presence or addition of steps, operations, elements, or combinations thereof. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted as ideal or overly formal in meaning unless explicitly defined in the present application Do not.

Manufacture of magnetic nanoparticles

First, prior to the description of the particle surface treatment method of the present invention, the method of producing particles used therefor will be described. The method of producing particles described below is an example of the particle used in the particle surface treatment method of the present invention and should not be construed as limiting the following examples.

The particles used in the particle surface treatment method of the present invention may have magnetism. For example, the particles may be selected from the group consisting of Cr, Ni, Ti, Zr, Fe, Co, Zn, Gd, Ta, Nb, Pt, Au, Mg, Mn, Pd, Sr, Ag, Ba, Cu, , And Pb. The particles may comprise an oxidized state. Further, the magnetic particles may contain a different kind of metal. For example, the magnetic particles may be represented by the following general formulas (1) to (4).

1

M (M is a metal atom or an alloy thereof)

Formula 2

M _a O _b (0 < a? 20, 0 < _b ? 20, M is a metal atom or an alloy thereof)

Formula 3

_{M c M 'd (0 <} c≤20, 0 <d≤20, M is exhibiting magnetism metal atom, or an alloy thereof; M' is a group 2 element, transition metal, Group 13 elements, 14 elements, 15 Group element, lanthanide element, and actinide element)

Formula 4

_{M a M 'e O b (} 0 <a≤20, 0 <e≤20, 0 <b≤20, M is exhibiting magnetism metal atom, or an alloy thereof; M' is a group 2 element, transition metal, 13 An element selected from the group consisting of Group IV elements, Group 14 elements, Group 15 elements, Lanthanide elements, and Actinium Group elements)

The general formulas 1 and 3 represent magnetic particles composed of a single metal or an alloy, magnetic particles made of a metal more than two kinds of metals, and general formulas 2 and 4 are metal particles composed of a single metal or alloy or a metal oxide containing more than two kinds of metals.

In the method of preparing the particles, an amorphous metal gel solution is prepared by dissolving a magnetic precursor and an anionic ligand in a solvent.

The magnetic precursor may be a metal nitrate compound, a metal sulfate compound, a metal fluoroacetoacetate compound, a metal halide (MX _a , M = Cr, Ni, Ti, Zr, Fe, Pb, Cu, W, Mo, Sn, Pb, X = F, Cl, Br, I, 0 & But are not limited to, compounds selected from the group consisting of metal perchlorate-based compounds, metal intercalation compounds, metal stearate-based compounds, and organometallic compounds.

The anionic ligand may be a neutral ligand such as an alkyltrimethylammonium halide series cation ligand, an alkyl acid, a trialkylphosphine, a trialkylphosphine oxide, an alkylamine, an alkylthiol and the like, and a neutral ligand such as a sodium alkylsulfate, a sodium alkylcarboxylate, Phosphate, sodium acetate, and the like, but is not limited thereto.

The solvent may be selected from the group consisting of an organic solvent, an aromatic solvent, a heterocyclic solvent, a sulphoside solvent, an amide solvent, a hydrocarbon solvent, an ether solvent, a polymer solvent, an ionic liquid solvent, a halogen hydrocarbon solvent, But is not limited thereto. In some cases, two or more kinds selected from the anionic ligands may be used together or sequentially.

In this case, in addition to a single kind of magnetic precursor, a metal halide (MX _a , M = Cr, Ni, Ti, Zr, Fe, Co, Zn, Gd, Ta, Nb, Pt, Au, Mg, A heterogeneous precursor material composed of a compound of Sr, Ag, Ba, Cu, W, Mo, Sn, Pb, X = F, Cl, Br, I and 0? A? 5. The metal (M) of the added heterogeneous precursor is a different kind of metal than the metal contained in the magnetic precursor. As a result, magnetic particles containing different metals can be produced. The heterogeneous precursor is preferably added in an amount of 1 to 99 parts by weight per 100 parts by weight of the magnetic precursor, but is not limited thereto. As the heterogeneous precursor material is contained in the magnetic precursor material, the magnetic properties of the finally obtained particles may be enhanced, or the magnetic properties may be variously changed to superphthalmagnetic, paramagnetic, ferromagnetic, antiferromagnetic, ferrimagnetic, Can be adjusted to the characteristics of the target.

Then, the prepared amorphous metal gel solution is heated to cause phase transition to crystalline particles having crystallinity. For example, the amorphous metal gel solution can be heated at 30 ° C to 200 ° C to form magnetic particles having a more stable crystal structure. In addition, the magnetic particles may be heated again at 100 ° C to 350 ° C to conduct a reduction reaction, so that magnetic clusters in which the magnetic particles are clustered together may be produced.

According to the above-described method, magnetic particles such as magnetite (Fe ₃ O ₄ ), hematite (? -Fe ₂ O ₃ ), and maghemite (? -Fe ₂ O ₃ ) can be produced.

In addition, the particles may have an average particle size of 1 to 200 nm, and clusters in which a plurality of the particles other than individual single particles are aggregated may be produced.

Particle Surface Treatment

Hereinafter, a particle surface treatment method according to an embodiment of the present invention will be described.

FIG. 1 is a flow chart of a process of a particle surface treatment method according to an embodiment of the present invention.

Referring to FIG. 1, a particle surface treatment method according to an embodiment of the present invention includes: (a) treating particles with an acid; (B) The acid-treated particles are then mixed with a water-soluble solvent. Subsequently, (c) is mixed with the surface treating agent. In the following, each step will be described in detail.

In the step (a) of acid-treating the particles, the acidic substance may be variously applied considering the acidity depending on the components of the magnetic particles. For example, the acid is hydrochloric acid (HCl), acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO _4), nitric acid (HNO _3), formic acid (Formic acid), citric acid (Citric acid), lactic acid (Lactic acid), Amino acid (Amino acid).

The acid may react with the particles to etch some of the surfaces of the particles. At this time, the surface of the etched particle can be partially charged with (+) electric charge.

In order to promote the reaction more effectively, the particles may be mixed with the acid and then stirred using a dispersing machine.

Subsequently, the particles charged with the positive electric charge are mixed with a water-soluble solvent (step b). The water-soluble solvent includes a precursor capable of introducing a hydroxyl group (-OH) into the particles charged with the positive electric charge. For example, when the water-soluble solvent is water, the water may be temporarily bonded to the surface of the particles charged with the positive electric charge. As the dehydrogenation reaction of the combined water takes place, hydroxyl groups can be introduced to the surface of the particles. Particles into which hydroxyl groups have been introduced can be more dispersed than the initial particles before the acid treatment.

Then, the organic ligand is bound to the hydroxyl group of the particle (step c). For example, the hydroxide-introduced particles may be mixed with a material containing the organic ligand and stirred using a dispersing machine. The organic ligand may include a long alkyl chain and a carboxyl group, an amine group, a vinyl group, and a phenyl group at the terminal of the alkyl chain. As the carboxyl groups and the hydroxyl groups on the particle surface are combined, long alkyl chains can be formed on the surface of the particles.

The organic ligand-containing material may be selected from the group consisting of ricinoleic acid, linoleic acid, monostearin, palmitic acid, octadecylamine, trioctylphosphine, It is also possible to use trioctylphosphine oxide, oleic acid, stearic acid, polymethylmethacrylate, polystyrene, solbitol monooleate, sorbitan trioleate Sorbitan trioleate, Myristoleic acid, Palmitoleic acid, Sapienic acid, Arachidonic acid,? -Linolenic acid, Eicosapenta At least one of Eicosapentaenoic acid, Erucic acid, Docosahexaenoic acid, Trioctylphosphate, Hexadecylamino, Fatty acid series and olefin series. The.

When a plurality of particles prepared by the above-described surface treatment method are dispersed in a water-soluble solvent or a fat-soluble solvent, a steric effect is generated between the plurality of particles by the organic ligands formed on the plurality of particles .

For example, when a plurality of the particles are exposed to an external strong magnetic field on a solvent, the particles on the solvent phase are repelled by the repulsive force due to the effect of the steric hindrance by the alkyl chain corresponding to the magnetic attractive force between the particles. It can be easily dispersed. In addition, a repulsive force between the particles can be controlled by treating a molecule having a polarization at the terminal of the alkyl chain.

By using the electrostatic, magnetic, and steric hindrances effect, the color of the photonic crystal structure can be expressed by changing the intervals of the particles, and it can be applied to the display field. In addition, since the prepared particles have dispersibility in a fat-soluble solvent, they can be encapsulated through a coacervation method using an O / W emulsification method. Accordingly, the encapsulated particles can be formed into a desired pattern by using a screen printing method, and can be applied as a functional film by coating the same on a transparent film.

The particle surface treatment method according to the present invention does not perform surface treatment of silica (TEOS) or polyethylene glycol (PEG), so that excellent magnetic properties are maintained, and dispersibility is also excellent even in a fat-soluble solvent owing to the steric hindrance effect. In addition, high-pressure production conditions and coatings of silica or PEG are not required, enabling mass production with a simple process.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are for illustrative purpose only and that the scope of the present invention is not limited to these embodiments.

<First Example >

&Lt; Production of magnetic iron oxide particles >

50 g of iron chloride hydrate, 50 g of sodium hydroxide and 50 g of water were added to 1000 ml of ethylene glycol as an organic solvent and dissolved at 90 캜 as magnetic precursors. The solution was refluxed at a high temperature of 190 DEG C and a black precipitate was obtained after the reaction was completed. This was centrifuged at 4,000 rpm for 30 minutes using a centrifuge and then purified by washing with ethanol and water to obtain iron oxide particles having an average particle size of 200 nm.

< Of the hydroxyl groups (-OH)  Surface treatment>

5 g of iron oxide particles having magnetic properties were mixed with 200 ml of 1 M hydrochloric acid (HCl), followed by stirring for 10 minutes using a dispersing machine. The surface potential of the iron oxide particles was not detected before mixing with hydrochloric acid, but the surface potential of the iron oxide particles after mixing with hydrochloric acid was 33.6 mV. Accordingly, as the surface of the iron oxide particles is etched, it can be confirmed that the particle surface is charged with a partial (+) electric charge.

Subsequently, the etched iron oxide particles were mixed with an aqueous solvent to remove remaining hydrochloric acid. At this time, the iron oxide particles charged with the (+) electric charge proceed to the dehydrogenation reaction with the water molecules present in the aqueous solvent, and a large number of hydroxyl groups (-OH) are bonded to the surface. Here, after mixing with the aqueous solvent, the surface potential of the iron oxide particles was detected as -23.5 mV.

Fig. 2 is an image obtained by analyzing iron oxide particles of the initial iron oxide particles (black color) in Fig. 1 and (red color) after the b-step treatment using TF-IR. Referring to FIG. 2, after step a and step b treatment, a typical detection peak of the 3,400 cm ^-1 to 3,650 cm ^-1 band of hydroxyl groups can be identified. Thus, it can be confirmed that hydroxyl groups are introduced on the surface of the iron oxide particles.

<Organic Ligand  Introduction>

5 g of iron oxide particles into which hydroxyl groups had been introduced were mixed with 200 ml of oleic acid, dispersed for 30 minutes using a dispersing machine, and stirred for 4 hours to prepare iron oxide particles surface-treated with oleic acid.

FIG. 3 is an image obtained by analyzing iron oxide particles of the initial iron oxide particles (black) and (red) after the c-step treatment using TF-IR. Referring to FIG. 3, it can be seen that the detection peaks of the typical alkyl groups of molecules forming oleic acid in the band of 2,850 cm ^-1 to 3,000 cm ^-1 and 1,375 cm ^-1 to 1,450 cm ^-1 are confirmed. In addition, the detection peak of a typical 1710 cm ^-1 band of a carboxyl group, which is a molecule constituting oleic acid, can be confirmed. Therefore, it can be confirmed that the surface of the magnetic particles is treated with oleic acid.

4 is data obtained by measuring the inter-particle dispersion according to the step a (black color), the b color (red color), and the c color (blue color) of FIG.

Referring to FIG. 4, if the degree of dispersion between the iron oxide particles is improved, the iron oxide particles should not coalesce with each other. Therefore, the size of the initial iron oxide particles should be close to 200 nm. Also, if the dispersion between the iron oxide particles is improved, the uniform particle density should show a large value. As the particle surface treatment of the present invention progresses, the particle size gradually approaches to 200 nm, which is the size of the initial iron oxide particles, and the particle density with the size of the initial iron oxide particles gradually increases. From these results, it was confirmed that the dispersibility of the particles increases as the particle surface treatment progresses.

<2nd Example >

The second embodiment was carried out in the same manner as the preparation of the magnetic iron oxide nanoparticles of the first embodiment and the surface treatment of the hydroxyl group. Hereinafter, the organic ligand treatment and its data analysis according to the second embodiment will be described.

200g of the organic ligand precursor was prepared by mixing 5g of octadecyl amine solids in 190g of non-polar solvent Tetrachlorethylene.

5 g of the iron oxide particles surface-treated with hydroxyl group were mixed with the organic ligand precursor, dispersed for 30 minutes using a dispersing machine, and stirred for 4 hours with a stirrer to prepare iron oxide particles surface-treated with octadecyl amine.

FIG. 5 is an image obtained by analyzing iron oxide particles of initial iron oxide particles (black) and organic ligand-treated (red) according to the second embodiment using TF-IR. Referring to FIG. 5, it is possible to confirm the detection peaks of the typical alkyl groups of 2,850 cm ^-1 to 3,000 cm ^-1 and 1,375 cm ^-1 to 1,450 cm ^-1 , which are molecules constituting the octadecyl amine. Further, octadecylamine can check the detected peak of an exemplary 3,300 cm ^-1 to 3,500 cm ^-1 and 1,600 cm ^-1 band in the amine molecule constituting the (octadecyl amine). Therefore, it can be confirmed that the surface of the magnetic particles is treated with octadecyl amine.

6 is data obtained by measuring the inter-particle dispersion degree produced by the second embodiment.

Referring to FIG. 6, the black color shows the inter-particle dispersion according to the step a, the red color b, and the blue color c, respectively.

As the particle surface treatment of the present invention progresses, the particle size gradually approaches to 200 nm, which is the size of the initial iron oxide particles, and the particle density with the size of the initial iron oxide particles gradually increases. From these results, it was confirmed that the dispersibility of the particles increases as the particle surface treatment progresses.

<Third Example >

The third embodiment was carried out in the same manner as in the preparation of the magnetic iron oxide nanoparticles of the first embodiment and the surface treatment of the hydroxyl group. Hereinafter, the organic ligand treatment and its data analysis according to the third embodiment will be described.

200 g of an organic ligand precursor was prepared by mixing 20 g of polystyrene solids with 10 wt% of nonpolar solvent in 180 g of tetrachlorethylene.

5 g of iron oxide particles having surface treated with hydroxyl groups were mixed with the organic ligand precursor, dispersed for 30 minutes using a dispersing machine, and stirred with a stirrer for 4 hours to prepare iron oxide particles surface-treated with polystyrene.

FIG. 7 is an image obtained by analyzing iron oxide particles of initial iron oxide particles (black) and organic ligands (red) according to the third embodiment using TF-IR. Referring to FIG. 7, a typical peak of the alkyl group of 2,850 cm ^-1 to 3,000 cm ^-1 band constituting the polystyrene can be confirmed. In addition, the detection peak of a typical 700 cm ^-1 to 900 cm ^-1 band of a phenyl group constituting polystyrene can be confirmed. Therefore, it can be confirmed that polystyrene is treated on the surface of the magnetic particles.

8 is data obtained by measuring the inter-particle dispersion degree produced by the third embodiment.

Referring to FIG. 8, black is represented by a, red is represented by b, and blue is represented by c.

As the particle surface treatment of the present invention progresses, the particle size gradually approaches to 200 nm, which is the size of the initial iron oxide particles, and the particle density with the size of the initial iron oxide particles gradually increases. From these results, it was confirmed that the dispersibility of the particles increases as the particle surface treatment progresses.

<Fourth Example >

The fourth embodiment was carried out in the same manner as in the preparation of the magnetic iron oxide nanoparticles of the first embodiment and the surface treatment of the hydroxyl group. Hereinafter, the organic ligand treatment and its data analysis according to the fourth embodiment will be described.

200g of the organic ligand precursor was prepared by mixing 5g of Monostearin solids in 190g of non-polar solvent Tetrachlorethylene.

5 g of the iron oxide surface-treated iron oxide particles were mixed with the organic ligand precursor, dispersed for 30 minutes using a dispersing machine, and stirred for 4 hours with a stirrer to prepare iron oxide particles surface-treated with monostearin.

FIG. 9 is an image obtained by analyzing iron oxide particles of initial iron oxide particles (black) and organic ligand (red) according to the fourth embodiment using TF-IR. Referring to FIG. 9, it can be seen that a typical peak of the alkyl group of 2,050 cm ^-1 to 3,000 cm ^-1 and 1,375 cm ^-1 to 1,450 cm ^-1 , which is a molecule constituting monostearin, can be confirmed. In addition, the detection peak of a typical 1,670 cm ^-1 to 1,780 cm ^-1 band of a carbonyl group which is a molecule constituting monostearin can be confirmed. Therefore, it can be confirmed that the surface of the magnetic particles is treated with monostearin.

10 is data obtained by measuring the inter-particle dispersion degree produced by the fourth embodiment.

Referring to FIG. 10, the black color shows the inter-particle dispersion according to the step a, the red color b, and the blue color c.

As the particle surface treatment of the present invention progresses, the particle size gradually approaches to 200 nm, which is the size of the initial iron oxide particles, and the particle density with the size of the initial iron oxide particles gradually increases. From these results, it was confirmed that the dispersibility of the particles increases as the particle surface treatment progresses.

Claims (14)

A particle surface treatment method for increasing dispersibility of particles,
Acid treating the iron oxide particles so that the iron oxide particles have a positive charge;
Mixing the acid-treated iron oxide particles with a water-soluble solvent to form hydroxyl groups (-OH) on the iron oxide particles;
And mixing the iron oxide particles formed with the hydroxyl groups with a surface treatment agent comprising an organic ligand which binds to the hydroxyl group,
Wherein the surface treatment agent containing the organic ligand comprises at least one of monostearin, octadecylamine, oleic acid and polystyrene. delete The method according to claim 1,
Wherein the iron oxide particles are clusters in which a plurality of iron oxide particles are aggregated. The method according to claim 1,
Wherein the acid comprises hydrochloric acid (HCl). The method according to claim 1,
Wherein when a plurality of the iron oxide particles are dispersed in a water-soluble solvent or a fat-soluble solvent, a steric effect is generated between the plurality of iron oxide particles by the organic ligands formed on the plurality of iron oxide particles. Processing method. delete delete delete delete delete delete delete delete delete

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