KR101054370B1 - Phase-transfer nanocapsules with metal nanoparticles fixed to the shell and a method of manufacturing the same - Google Patents

Abstract

The present invention relates to a phase-transfer nanocapsules in which metal nanoparticles are fixed to a shell, and a method of manufacturing the same. More specifically, the phase-transfer material is used as a core, and the polymer and the metal nanoparticles are coated on the outer circumferential surface of the core to form a nano-sized capsule. By increasing the durability and increasing the heat transfer rate of the external environment to maximize heat sensitivity and heat control efficiency, it can be applied to biomedical applications such as functional clothing.

Phase Transition Material, Core-Shell Structure, Metal Nanoparticles, Condensation Polymerization

Description

Phase transfer nanocapsules having metal nanoparticles fixed in a shell and a method of manufacturing the same {Fabrication of metal nanoparticle immobilized phase change material nanocapsule}

The present invention relates to a phase-transfer nanocapsules in which metal nanoparticles are fixed to a shell, and a method of manufacturing the same. More specifically, the phase-transfer material is used as a core, and the polymer and the metal nanoparticles are coated on the outer circumferential surface of the core to form a nano-sized capsule. Phase change nanocapsules where metal nanoparticles are fixed to shells applicable to biomedical applications such as functional clothing by maximizing durability and increasing heat transfer rate of external environment by forming It is about.

The core-shell structured capsule using the conventional phase-transfer material has a lack of durability, which makes it difficult to use the capsule in the real life because the capsule is easily broken, and studies to increase the heat transfer rate even after the capsule has been manufactured have received much attention. . However, many studies on increasing the heat transfer rate have not been conducted at present, and particularly, studies on introducing metal nanoparticles have not been conducted.

As a method of encapsulating a core-shell structure using a phase-transfer material, Korean Patent No. 284,192 has a diameter of 0.1 to 10 mm for PCM particles, a thickness of 2.5 to 50 μm per polymer coating layer, and a diameter of 0.1 to 10 mm for microcapsules. Spherical heat storage capsules are disclosed, but they are not suitable for mass production because they require a refrigerant such as liquid nitrogen and drop the inorganic hydrate in a molten state during the manufacturing process. In addition, in order to solidify the molten inorganic hydrate, there is a disadvantage in that the size of the container containing the refrigerant must be long because the drop path must be long.

On the other hand, the latent heat storage material microencapsulated of the heat storage material by interfacial polymerization of the polymer using a wax as a PCM is disclosed in US Patent No. 4,513,053, the latent heat storage material is produced after the heat storage material in the shape of a pill with a curved edge, The encapsulation of the inorganic salt hydrate and mechanical strength have been improved by encapsulating it with various kinds of polymer materials. However, the surface area per unit volume is small compared to the spherical encapsulation, so that the thermal response is poor and the manufacturing cost is high.

In addition, Korean Patent Publication No. 2003-0018155 discloses a microencapsulation method of a phase change material using an emulsion method, the formation and stabilization of smooth microparticles using a surfactant, and a step 1 microencapsulation step of a phase change material using a co-surfactant. And two-stage process consisting of two-stage micro-encapsulation process using tangential spray coater and tangential spray coater, which is more complicated than one-stage process. Was 10 to 100㎛, indicating that the size is insufficient to increase the structural stability by distributing the force by reducing the size.

Therefore, in order to strengthen the durability of the core-shell capsule made of a phase-transfer material, a strong material may form a shell, or the capsule may be manufactured in nanometer size to withstand pressure by using force dispersibility. A method of constructing a shell made of a material having a high strength may complicate the manufacturing process, and the strength of the general material may interfere with heat transfer of the phase change material in the shell.

In addition, it is necessary to further increase the heat transfer rate between the phase change material and the outside.

It is an object of the present invention to provide a nanocapsule having excellent physical properties and a method for preparing the same for improving the durability of a capsule in a nanocapsule using a phase change material and a heat transfer rate between the phase change material and the outside.

In order to achieve the above object, the present invention provides a nanocapsule including a material to be phase-changed at room temperature and a polymer shell surrounding the shell, the metal particles are fixed to the surface of the shell.

The invention also

Homogenizing the solution containing the monomer and the monomer which are phase-changed at room temperature to nanometer size;

Preparing an emulsion by mixing the homogenization solution and an emulsifier;

Encapsulating the phase change material through polymerization of the emulsion and the co-monomer; And

It provides a method for producing a nanocapsule comprising the step of fixing the metal particles to the polymer shell of the capsule.

The present invention also provides a functional garment comprising the nanocapsules according to the invention.

Since the nanocapsules of the present invention are smaller than conventional capsules using phase change materials, even if they are made of the same material, the nanocapsules may increase the force required until the capsules are destroyed because they induce force dispersion.

In addition, since the metal nanoparticles are fixed to the polymer shell, it is possible to maximize the heat transfer rate between the phase change material and the external environment by increasing the heat transfer rate due to the temperature difference between the internal phase change material and the external environment.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated concretely.

The present invention relates to a nanocapsule comprising a material to be phase-changed at room temperature and a polymer shell surrounding the shell, wherein metal particles are fixed to the surface of the shell.

The nanocapsules of the present invention exhibit a form in which the material that is phase-changed at room temperature forms a core portion, the polymer layer is surrounded on the outside thereof, and the metal nanoparticles are fixed to the polymer layer. Since it induces the dispersion of force, the force required to break the capsule can be increased, and the metal particles are fixed to the outside of the polymer to increase the heat transfer rate due to the temperature difference between the phase change material and the external environment of the core. The phase change material is characterized by being able to be used for biomedical (biomedical) use because it causes phase transition at room temperature.

In the present specification, "phase transfer material" refers to a material that can be used for the purpose of storing energy or maintaining a constant temperature by using a large heat absorption and release effect of latent heat, and "latent heat storage material", or " Phase change material. The "latent heat" refers to heat that absorbs or releases heat when a substance phase changes. The latent heat is much larger than heat absorbed or released according to a temperature change without phase transition.

In addition, "a substance which becomes a phase change at room temperature" means the phase change substance defined above which becomes phase change in the normal room temperature range including body temperature, for example, tetradecane, hexadecane, octadecane, eicosan, la Uric acid, polyglycol, polyethylene glycol, camphor, hexadecanone, capric acid, caprylic acid, or the like may be used alone or in combination of two or more thereof.

The polymer is to have a capsule form by coating the outer circumferential surface of the phase change material constituting the core portion, and may be used without limitation as long as the phase change material is a compound capable of continuously maintaining the capsule form even if it is changed into a solid or a liquid. For example, polyurethane, polyester, polyamide, melamine resin, urea resin, gelatin cellulose and the like can be used alone or in combination of two or more.

The metal particles are used to increase the heat transfer rate of the phase change material and the external environment of the core part, and may be used without limitation as long as the material has good heat transfer and can be completely fixed by interaction with the polymer shell forming the outer wall. have. For example, gold, silver, copper, iron particles, or the like can be used. More specifically, when the polymer shell exhibits (+) charges, metal particles with (-) charges are used, and when the polymer shell exhibits (-) charges, metal particles with (+) charges are used. Good to do.

The nanocapsules of the present invention having the core-shell structure may have a size of 50 to 1000 nm, more specifically, 100 to 600 nm.

The invention also

Homogenizing the solution containing the monomer and the monomer which are phase-changed at room temperature to nanometer size;

Preparing an emulsion by mixing the homogenization solution and an emulsifier;

Encapsulating the phase change material through polymerization of the emulsion and the co-monomer; And

It relates to a method for producing a nanocapsule comprising the step of fixing the metal particles to the polymer shell of the capsule.

Referring to the method of manufacturing the nanocapsules of the present invention in detail as follows.

The first step is a homogenization step of physically crushing a solution prepared by mixing a material for phase change at room temperature and a monomer for polymer formation to a nanometer size.

The type of the material that is phase-changed at room temperature is as described above.

The monomer for forming the polymer may be used without limitation as long as it is a monomer capable of causing a polymerization reaction, more specifically, a condensation polymerization when preparing a capsule of the core-shell structure by a polymerization reaction in a subsequent step, but more preferably two or more isocyanates Compounds containing groups are preferred.

Compounds containing two or more isocyanate groups include tolylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, or octamethylene diisocyanate, or the like. Two or more kinds can be used.

The materials and monomers which are phase-changed at room temperature may be used in a mixture of 5: 1 to 1: 1 by weight. If within the content range, the physical strength of the polymer shell can be produced firmly.

Wherein the step of homogenizing by physically crushing to the nanometer size is to crush the droplets to nanometer size using a physical device such as a homogenizer (Homogenizer), if the separation method commonly used in the art for this purpose Anything may be used.

The homogenization may be carried out by stirring for 5 to 30 minutes at 5000 to 20,000 rpm, but is not particularly limited thereto.

In the method for preparing nanocapsules of the present invention, the second step is a step of preparing an emulsion by mixing a mixed solution of a phase change material and a monomer crushed into a nanometer and an emulsifier solution and stirring at 60 to 80 ° C.

The emulsifier can be polymerized with the monomer, emulsifies the phase change material to produce stable droplets of small size, and can be used for chemical bonding of the monomer to the reactor for polymerization.

The emulsifier can be used without limitation so long as it is a compound having a reactive group, preferably a hydroxyl group, with the reactor of the monomer. For example, poly (styrene sulfonic acid-co-maleic acid) or styrene-maleic anhydride copolymer may be used alone or in combination of two or more.

The emulsifier is preferably contained in 0.2 to 1 parts by weight based on 100 parts by weight of the mixed solution. This is because the dispersion stability of the prepared nanocapsules is in the highest content range.

In the method for producing a nanocapsule of the present invention, the third step is to mix the emulsified emulsion mixture solution and the co-monomer capable of proceeding the polymerization reaction to condensation polymerization (condensation polymerization) at 60 to 80 ℃ for 3 to 12 hours Encapsulating the phase change material.

It is preferable that the said co-monomer is a compound containing two or more amine groups at the terminal.

Compounds containing two or more amine groups at the terminal may be ethyldiamine, propanediamine, hexanediamine, phenylenediamine, or polyoxyethylene bis-amine. These may be used alone or in combination of two or more.

The co-monomer may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the emulsion mixed solution. This is because the physical strength of the polymer shell is maintained within the content range.

In the method for producing a nanocapsule of the present invention, the fourth step is to mix the encapsulated phase change material and the metal particles and stir for 1 to 24 hours to fix the metal particles to the polymer shell.

The metal particles may be prepared using a conventional metal nanoparticle manufacturing method, and are not particularly limited.

According to one embodiment of the present invention, the metal particles may be prepared by mixing silver nitrate and sodium citrate in an aqueous solution and stirring for 20 minutes to 2 hours at a temperature of 60 to 90 ℃ nanometer size silver particles.

The metal particles are preferably included in an amount of 1 to 20 parts by weight based on 100 parts by weight of the encapsulated phase change material. It is because the heat transfer efficiency is the largest when it is in the said content range.

The present invention also relates to a functional garment comprising nanocapsules according to the invention.

Since the nanocapsules of the present invention can absorb, release and store thermal energy at room temperature, they can be used in biomedical applications such as functional clothing.

Hereinafter, the present invention will be described in more detail through examples according to the present invention and comparative examples not according to the present invention, but the scope of the present invention is not limited to the examples given below.

Example 1 Preparation of Nanocapsules

3 g of tolylene diisocyanate [Sigma-Aldrich, USA], which can be polymerized into a capsule membrane material by condensation polymerization, and 9 g of octadecane [Sigma-Aldrich, USA], a phase change material as a capsule core material. , 5 g of acetone [Duksan Co., Ltd. Korea] was added to 80 g of water, followed by forced emulsification by stirring at 8000 rpm for about 10 minutes using a homogenizer [T25 basic ULTRA-TURAX, IKA, Germany].

Next, the solution of the forced emulsification was mixed at 600 rpm in a solution in which 6 g of Poly (styrene sulfonic acid-co-maleic acid) [Sigma-Aldrich, USA] was dissolved in 60 g of water.

Next, a solution of 0.005 g of poly (styrene sulfonic acid-co-maleic acid), 5 g of ethyldiamine [Junsei Chemical, Japan] and 5 g of water was added to the above emulsified solution and poly (styrene sulfonic acid- Co-maleic acid) was slowly mixed into the mixed solution, the temperature was maintained at 60 ℃ and stirred at 600rpm to react for 4 hours to prepare a nanocapsules.

The silver particles were mixed with a solution of 0.3 g of silver nitrate [Sigma-Aldrich, USA] dissolved in 10 g of water and 0.1 g of sodium citrate [Sigma-Aldrich, USA] dissolved in 10 g of water, followed by stirring at 80 ° C. for about 1 hour. As a result, silver particles having a size of about 5 nm are formed.

Next, 10g of the prepared solution containing the nanocapsules and 1g of the solution containing the negatively charged silver particles were stirred at room temperature for about 3 hours to prepare coreshell phase-transfer nanocapsules in which silver particles were fixed.

As shown in Figures 1 to 3, the size of the prepared nanocapsules was found to have a size of about 100 to 600 nm.

1 and 2 show SEM and TEM photographs of the core-shell nanocapsules according to an embodiment of the present invention.

3 is a SEM photograph of the nanocapsules of the core-shell structure to which the silver particles of the present invention are fixed.

Claims (15)

Nanocapsules including a material to be phase-changed at room temperature and a polymer shell surrounding the shell, the metal particles are fixed to the surface of the shell. The method of claim 1, At room temperature, the phase change material is one or more nanocapsules selected from the group consisting of tetradecane, hexadecane, octadecane, eicosane, lauric acid, polyglycol, polyethylene glycol, camphor, hexadecanone, capric acid and caprylic acid . The method of claim 1, Nanocapsules wherein the polymer is at least one selected from the group consisting of polyurethane, polyester, polyamide, melamine resin, urea resin and gelatin cellulose. The method of claim 1, Nanocapsules wherein the metal particles are at least one selected from the group consisting of gold, silver, copper and iron particles. The method of claim 1, Nanocapsules are nanocapsules having a size of 50 to 1000 nm. Homogenizing the solution containing the monomer and the monomer which are phase-changed at room temperature to nanometer size; Preparing an emulsion by mixing the homogenization solution and an emulsifier; Encapsulating the phase change material through polymerization of the emulsion and the co-monomer; And Method of manufacturing a nanocapsule comprising the step of fixing the metal particles to the polymer shell of the capsule. The method of claim 6, A method for producing a nanocapsule, wherein the monomer is a compound containing two or more isocyanate groups. The method of claim 7, wherein The compound containing two or more isocyanate groups is one selected from the group consisting of toylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate and octamethylene diisocyanate Nanocapsules manufacturing method as described above. The method of claim 6, Emulsifier is a method for producing a nanocapsule which is a compound containing a hydroxyl group. 10. The method of claim 9, A method for producing nanocapsules wherein the compound containing a hydroxyl group is at least one selected from the group consisting of poly (styrene sulfonic acid-co-maleic acid) and styrene-maleic anhydride copolymer. The method of claim 6, A method for producing a nanocapsule, wherein the co-monomer is a compound containing two or more amine groups at its terminals. The method of claim 11, Compounds containing at least two amine groups at the terminal are composed of ethyldiamine, propanediamine, hexanediamine, phenylenediamine and polyoxyethylene bis-amine. At least one nanocapsule manufacturing method selected from the group. The method of claim 6, Encapsulation step is a method of producing a nanocapsules to perform condensation polymerization (condensation polymerization) for 3 to 12 hours at 60 to 80 ℃. The method of claim 6, Fixing the metal particles is a method for producing a nanocapsule which is stirred for 1 to 24 hours by mixing the encapsulated phase change material and the metal particles. Functional garment comprising the nanocapsule according to any one of claims 1 to 5.

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