TWI740826B - Self-assembly type janus microparticle and manufacturing method thereof - Google Patents

Abstract

The present disclosure relates to a self-assembly type Janus microparticle and a method for preparing the same.  In accordance with the present disclosure, a Janus microparticle with a precisely controlled degree of phase separation can be prepared and stable interfacial assembly can be achieved by selectively coating a metal oxide, etc. only on one surface of the particle.  Because a Janus microparticle with an anisotropic structure having a precisely controlled degree of phase separation and clear amphiphilicity can be produced in large scale, the Janus microparticle and the method for preparing the same of the present disclosure is widely applicable to various fields.

Description

Self-assembled JANUS particles and manufacturing method thereof

This specification is about a self-assembled Janus particle and its preparation method.

The reference of the present invention is Korean Patent Publication No. 10-1997-0025588 (Jun. 24, 1997).

In the cosmetic and pharmaceutical fields, the development of dosage forms can stably encapsulate substances that are effective on the skin to ensure their effective effects on the skin and improve skin conditions. However, many physiologically active substances are poorly soluble or unstable in the water phase, making the entire system unstable.

Technologies that are more stable and easy to encapsulate these substances in a dosage form have been developed to overcome this. Representative examples include emulsified particles formed by semi-formulation prepared by using a surface active agent with a special hydrophilicity/hydrophobic ratio by processing with a high-pressure emulsification device, etc., and the active ingredient is formed by using plants or The phospholipids of animals, etc. form one or more layers to encapsulate liposomes.

Moreover, research on Pickering emulsion is ongoing, which can use fine particles to form stable giant emulsion particles. The fine particles in the Pickering emulsion exhibit different surface contact angles between the water phase and the oil phase according to the properties of the particles, and the oil/water or water/oil giant emulsion particles are formed according to the contact angle.

Although research on fine particles that can be widely used (such as Pickering emulsification, etc.) is ongoing, due to limited control of the fine particle morphology, uncertain amphiphilicity, limited ability to maintain giant emulsified particles, and difficulty in mass production And other problems make practical application difficult.

In one aspect, this specification is to provide a self-assembled Janus particle with obvious phase separation and a preparation method thereof, so that the morphology of the Janus particle can be freely controlled, and the retention time of emulsion droplets can be improved. Produce the same Janus pellets. Technical solutions

In one aspect, this specification provides a Janus particle containing: a first domain containing polystyrene; and a second domain containing poly(tetradecyl acrylate) ( a second domain containing poly(tetradecyl acrylate)).

In another aspect, this specification provides an emulsified composition containing the Janus particles and a cosmetic composition containing the emulsified composition.

In another aspect, this specification provides a method for preparing a Janus particle and a method for controlling the structure of an amphiphilic particle. Beneficial effect

In one aspect, this specification provides a Janus particle with obvious phase separation and a preparation method thereof. The amphiphilic Janus particles are suitable for various fields and can be produced on a large scale. Moreover, this specification provides a method for controlling the structure of the particles, so that the degree of phase separation of the Janus particles can be precisely controlled according to the purpose and use of the particles.

Best embodiment

Hereinafter, this specification is described in detail.

In this specification, a Janus particle refers to a particle with a size of one micron, which has two parts with different structures or properties. In a narrow sense, it refers to a spherical particle in which different parts have different structures or properties. Usually the difference in structure or properties is derived from the difference in internal or surface structure, bonding, or physical or chemical properties.

In this specification, a hydrophilic inducing group refers to a group that can form a bond (including covalent bond) on the surface of polystyrene, thereby allowing a hydrophilic material to bond (including hydrogen bond) to it And cause the hydrophilic material to be coated on the outside of the polystyrene.

In this specification, a diameter refers to an average diameter of a particle and a diameter calculated from an equivalent sphere including an imperfect sphere. For example, the diameter of the equivalent sphere may be calculated as an equivalent sphere with the same properties as the actual particle, such as: a sphere with the same maximum length, a sphere with the same mass, a sphere with the same volume, a sphere with the same surface area , Spheres that can pass through the same mesh, spheres with the same precipitation speed, etc. The diameter can be averaged.

In one aspect, the Janus particles provided in this specification include: a first domain containing polystyrene; and a second domain containing poly(tetradecyl acrylate).

In an exemplary embodiment, a hydrophilicity-inducing group may be covalently bonded to the polystyrene surface of the first domain.

In an exemplary embodiment, the first domain may include: a polystyrene-containing core; and a hydrophilic material coating layer covering the core.

In an exemplary embodiment, the hydrophilic material coating layer may contain a hydrophilic material bonded to the hydrophilicity inducing group, which is covalently bonded to the surface of the polystyrene.

In an exemplary embodiment, the hydrophilicity inducing group may include one or more selected from the group consisting of poly(vinyl alcohol), polyvinylpyrrolidone, and poloxamer. In particular, it may be polyvinylpyrrolidone. The poloxamer may be poloxamer 407 or poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer.

In an exemplary embodiment, the hydrophilic material may include silica nanoparticles.

In this specification, the degree of duality is defined as D/D ₀ , where D is the shorter diameter of the second domain of the Janus particle, and D _{0 is} the overall diameter of the particle (see Figure 10c). In an exemplary embodiment, the Janus particles may have a degree of double-sidedness of the second domain of 0.25-0.75 relative to the entire particle. In another exemplary embodiment, the degree of duality may be: 0.25 or greater, 0.3 or greater, 0.35 or greater, 0.37 or greater, 0.4 or greater, 0.45 or greater, 0.5 or Larger, 0.55 or larger, 0.6 or larger or 0.7 or larger, or 0.75 or smaller, 0.7 or smaller, 0.6 or smaller, 0.55 or smaller, 0.5 or smaller, 0.45 or smaller, 0.4 or less, 0.37 or less, 0.35 or less or 0.3 or less, especially 0.45-0.55.

In an exemplary embodiment, the Janus particles may have a diameter ranging from 1 micrometer (μm) to 100 micrometer equivalent spheres. In another exemplary embodiment, the diameter may be: 1 μm or larger, 3 μm or larger, 5 μm or larger, 7 μm or larger, 10 μm or larger, 15 μm or larger , 20 μm or larger, 30 μm or larger, 60 μm or larger or 80 μm or larger, or 100 μm or smaller, 80 μm or smaller, 60 μm or smaller, 30 μm or smaller , 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, 5 μm or less or 3 μm or less, especially 3-10 μm.

Because the Janus particles have obvious phase separation (see Figure 2, Figure 3 and Figure 4), the Janus particles can have various applications in fields that require significant phase separation such as amphiphilicity. Especially because the hydrophobic part and the hydrophilic part are clearly separated, when coated with silica nanoparticles, it can be rendered hydrophilic (see Figures 4 and 5). Compared with the existing particles that are difficult to separate, the Janus particles can It has remarkable and outstanding properties. Moreover, it may be widely used in various applications including Pickering emulsion because of its obvious amphiphilic nature.

In another aspect, this specification provides an emulsified composition containing the Janus particles.

In an exemplary embodiment, the emulsion may be a Pickering emulsion.

In an exemplary embodiment, when the degree of double-sidedness of the second domain is equal to or greater than 0.25 and less than 0.37 relative to the entire Janus particles, the emulsion is the emulsion may be water-in-oil (w/o) emulsification When the degree of double-sidedness is equal to or greater than 0.37 and less than 0.75, it is an oil-in-water (o/w) emulsion.

In an exemplary embodiment, the emulsified composition may improve the retention time of an emulsion droplet. In another exemplary embodiment, the holding time may be: 20 hours or longer, 40 hours or longer, 60 hours or longer, 80 hours or longer or 100 hours or longer, especially 60 hours or longer. Longer.

It is difficult to maintain the quality of the existing emulsified composition, which is caused by the short retention time of the emulsion droplets, which makes it difficult to improve this problem. On the contrary, the emulsion composition of one aspect of the specification has significantly improved droplet retention time, because the degree of double-sidedness is controlled at or close to 0.5 (see Figure 13).

In another aspect, this specification provides a cosmetic composition containing the emulsified composition.

The dosage form of the cosmetic composition in this manual is not particularly limited. For example, it may be formulated into tonic, scalp treatment, hair cream, ointment, softening lotion, astringent lotion, Nourishing lotion, eye cream, nourishing cream, massage cream, cleansing cream, cleansing foam, cleansing water , Powder, essence, pack, body lotion, body cream, body oil, body essence, base Makeup (makeup base), foundation (foundation), hair dye (hairdye), shampoo (shampoo), conditioner (rinse), body cleanser, toothpaste, mouthwash, Lotion, gel, paste, spray, etc.

In another aspect, this specification provides a method for preparing the Janus particles, which includes: (1) a process of synthesizing polystyrene particles by dispersion polymerization; The process of dispersing the polystyrene particles in a mixed solvent; (3) The process of expanding the polystyrene particles by absorbing the tetradecyl acrylate monomer into the polystyrene particles by Adding the tetradecyl acrylate monomer to the mixed solvent; and (4) a process of polymerizing the tetradecyl acrylate by photopolymerization and causing phase separation.

In an exemplary embodiment, the dispersion polymerization reaction in the process (1) may be carried out in the presence of a compound capable of forming hydrophilicity-inducing groups on the surface of the polystyrene particles.

In an exemplary embodiment, the compound used to form a hydrophilicity-inducing group may be one or more selected from poly(vinyl alcohol), polyvinylpyrrolidone, polyethyleneimine or poloxamer. The group formed. The poloxamer may be poloxamer 407 or poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer.

In an exemplary embodiment, the method may further include (5) after the process (4) by bonding silica nanoparticles to the hydrophilicity inducing group to form a hydrophilic material coating Layer of manufacturing process.

_{In an exemplary embodiment, the mixed solvent may be a mixture of C 1} -C ₆ alcohol and water in a volume ratio of 4:1-1:4 in the process (2). In another exemplary embodiment, the C ₁ -C ₆ alcohol may particularly be ethanol. In another exemplary embodiment, the volume ratio may be 1-4:1-4, especially 3:2.

In an exemplary embodiment, the process (3) may be performed by adding one or more crosslinking agents and photopolymerization initiators. The crosslinking agent may include ethylene glycol dimethacrylate (EGDMA) and the photopolymerization initiator may include 1-hydroxycyclohexyl phenyl ketone.

With this preparation method, Janus particles with obvious phase separation can be prepared on a large scale. As for the existing Janus particles, which have the problem of unclear phase separation and difficulty in mass production, this specification enables the obvious phase separation of Janus particles to be prepared on a large scale (see Figures 2 and 4).

In another aspect, this specification provides a method for controlling the structure of amphiphilic particles, wherein the amphiphilic particles are prepared by a method including: (1) Synthesis of polystyrene particles by dispersion polymerization (2) Disperse the polystyrene particles in a mixed solvent of alcohol and water; (3) Expand the polystyrene particles by absorbing alkyl acrylate monomers into the polystyrene particles, which is By adding the alkyl acrylate monomer to the mixed solvent; and (4) polymerizing the alkyl acrylate by photopolymerization and causing phase separation, and the particle structure is controlled by one or more of the following: The carbon number of the alkyl group in the alkyl acrylate monomer; changing the mixed solvent; and changing the expansion ratio of the polystyrene particles.

In an exemplary embodiment, the carbon number of the alkyl group may vary in the range of 5-20. The alkyl carbon number may particularly be 6, 12, 14, or 16, and more particularly 14. The alkyl acrylate may contain lauryl methacrylate.

In an exemplary embodiment, the mixed solvent may be changed by changing _{the volume ratio of C 1} -C ₆ alcohol and water in the range of 4:1-1:4. In another exemplary embodiment, the C ₁ -C ₆ alcohol may particularly be ethanol. In another exemplary embodiment, the volume ratio may be 1-4:1-4, especially 3:2.

In this specification, the expansion ratio refers to the weight ratio (w/w) of the second domain to the first domain in the particle. When the alkyl acrylate monomer contained in the polymerized polystyrene expands the particles, the expansion ratio may be changed by controlling various conditions, such as the number of monomers, the solvent, temperature, and time. Wait.

In an exemplary embodiment, the expansion ratio may be changed so that the double-sidedness range is 0.25-0.75. In another exemplary embodiment, the expansion ratio may be changed so that the degree of double-sidedness is: 0.25 or greater, 0.3 or greater, 0.35 or greater, 0.37 or greater, 0.4 or greater, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more or 0.7 or more; or 0.75 or less, 0.7 or less, 0.6 or less, 0.55 or less, 0.5 or less , 0.45 or less, 0.4 or less, 0.37 or less, 0.35 or less or 0.3 or less, especially 0.45-0.55.

The degree of phase separation can be precisely controlled by changing the alkyl carbon number in the alkyl acrylate monomer or by changing the alcohol:water volume ratio of the mixed solvent (see Figures 9a-9h).

Moreover, because the degree of double-sidedness can be precisely controlled by changing the expansion ratio (see Figures 10a-10c), the contact angle and the retention time of the Pickering emulsion (Figure 12) during the interface assembly process (Figure 12) Figure 13) can be significantly improved.

Hereinafter, this specification will be described in detail through examples. However, the following examples are only for illustrative purposes, and it is obvious that the scope of this specification is not limited by the examples for those of ordinary skill in the art. <Example 1> Preparation of Janus particles

In order to prepare the Janus particles in this manual, styrene, polyvinylpyrrolidone (PVP, M _n =40,000 g mol ^-1 ), absolute ethanol, poly(vinyl alcohol) (PVA, M _w = 13,000-23,000 g mol ^-1 , 87-89% hydrolysis), ethylene glycol dimethacrylate (EGDMA, 98%), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, 99%), hexyl acrylate ( 98%), dodecyl acrylate (96%), 9-vinylanthracene (VA) and Poloxamer 407 (Pluronic F-127). 2,2'-Azobis(isobutyronitrile) (2,2'-Azobis(isobutyronitrile)) (AIBN, 98%) was purchased from Junsei (Japan), tetradecyl acrylate (TA) and sixteen Alkyl acrylates were purchased from TCI (Japan) and silica nanoparticles (KE-P10, KE-P30) were purchased from Nippon Shokubai (Japan). Deionized distilled water is used as water.

A bright field microscope (Axio Vert. A1, Carl Zeiss, Germany) was used to observe the particles. The Janus phase of the particles was examined with a fluorescence microscope (Axio Vert. A1, Carl Zeiss, Germany). In this case, 9-vinylanthracene (0.1 wt%, Aldrich) was copolymerized with polystyrene polymer as the fluorescent probe. Observe the morphology of each particle with a scanning electron microscope (SEM, S-4800, Hitachi, Japan), and analyze the electron microscopic image to determine the diameter. In this analysis, more than 100 particles were analyzed and the average value was taken. X-ray photoelectron spectroscopy (XPS, Theta Probe, Thermo Fisher Scientific, USA) was used to analyze the chemical properties of the particle surface.

The Janus particles of this specification were prepared as shown in Figure 1.

First, a dispersion polymerization reaction is used to prepare polystyrene particles with an equivalent spherical diameter of 3 μm.

Specifically, 5 mL of styrene, 1.0 g of polyvinylpyrrolidone (PVP), and 0.05 g of AIBN were dissolved in absolute ethanol (50 mL, 200 proofs) in a 100-mL round bottom flask. During the reaction, nitrogen was purged for 5 minutes to remove oxygen. Then, polymerize at 70 ºC in an oil bath while stirring at 60 rpm for 48 hours. After the polymerization reaction, the polystyrene particles were repeatedly washed with ethanol, and the ethanol/water mixture (1:1, v/v) was centrifuged to remove the remaining monomers and additives. The polystyrene particles were stored in an ethanol/water mixture (2/1, v/v). The concentration of the particles is set to 10 wt%.

The first image in Figure 2 is a bright-field microscopic image of the polystyrene particles. X-ray photoelectron spectroscopy (XPS) analysis confirmed that polyvinylpyrrolidone was covalently bonded to the polystyrene surface (Figure 8). Because the polyvinylpyrrolidone (PVP) was grafted onto the polystyrene surface during the dispersion polymerization reaction of the polystyrene (PS), the polystyrene seed showed a high-strength N peak (Figure 8, a). After the polystyrene/poly(tetradecyl acrylate) Janus particles were prepared, the N peak intensity decreased because the polystyrene portion decreased compared to the entire particle (Figure 8, b). According to this, it was confirmed that the polyvinylpyrrolidone was grafted onto the surface of the polystyrene.

Then, monodisperse Janus particles were prepared by expansion and photopolymerization using tetradecyl acrylate monomer.

In particular, 0.1 g of the synthetic polystyrene particles were dispersed in an ethanol/water mixture solvent (5 mL, 3/2, v/v). In order to avoid aggregation, the dispersion was sonicated for 30 minutes at room temperature. In order to stabilize the particles, poloxamer 407 (Pluronic F-127, 2 wt%) and poly(vinyl alcohol) (PVA, 2 wt%) were added. Then, tetradecyl acrylate monomer (65 wt%), ethylene glycol dimethacrylate (EDGMA, 20 wt%) as a crosslinking agent, and 1-hydroxycyclohexyl as a photopolymerization initiator A mixture of phenyl ketone (Irgacure 184, 15 wt%) was added to the polystyrene particle dispersion. Then, it was expanded for 6 hours at room temperature while rotating at 50 rpm. The second image in FIG. 2 is a bright-field microscopic image of the expanded particles.

After the expansion was completed, the mixture was phase separated by exposing the mixture to UV irradiation (λ=365 nm, JHC1-051S-V2, A&D, Korea) for 5 minutes. The Janus particles are cleaned with ethanol/water (1/1, v/v) to remove excess monomers and additives.

The third image in Figure 2 is a bright-field microscopic image of the phase-separated particles. The electron microscopic image confirms that the particles are spherical (Figure 6, the second image), and the fluorescent microscopic image confirms that the polystyrene part and the poly(tetradecyl acrylate) part of the spherical particles are obvious Phase separation (Figure 6, first image, the bright part is the polystyrene part and the dark part is the poly(tetradecyl acrylate) part). The comparison result of the polystyrene particles and the Janus particles is shown in FIG. 7. <Example 2> Combination of silica nanoparticles

In order to impart amphiphilic properties to the Janus particles, silicon dioxide nanoparticles were hydrogen-bonded to the polystyrene surface to covalently bond polyvinylpyrrolidone (Figure 3).

In particular, 0.01 g of the polystyrene/poly(tetradecyl acrylate) Janus particles and 0.01 g of silica were dispersed in an ethanol/water mixture solvent (2.5 mL, 1/1, v/v) Nano particles. Then, the silica nanoparticle dispersion was added dropwise to the Janus particle dispersion within 30 minutes while slowly sonicating the mixture at room temperature. Then, the mixture was rotated at a speed of 50 rpm at room temperature for 24 hours. In order to remove the remaining silica nanoparticles, the mixture was centrifuged repeatedly using an ethanol/water mixture solution (1/1, v/v). Store the resulting amphiphilic Janus particles in water at room temperature.

The bonded silica nanoparticle has a diameter of 100 nm or 300 nm. The electron microscopic image of the prepared amphiphilic Janus particles is shown in Figure 4. <Example 3> Preparation of Pickering Emulsion-Pickering Emulsion was prepared by using the amphiphilic Janus particles coated with silica particles.

A Pickering emulsion is prepared by using amphiphilic Janus particles coated with silica particles.

In particular, 1 wt% of the amphiphilic Janus particles coated with the silica particles were finely dispersed in water under sonic vibration for 5 minutes at room temperature. Then, 10 vol% hexadecane was added to the Janus particle dispersion. The mixture was then vortexed for 10 seconds, which produced a Janus particle-stable Pickering emulsion. The amphiphilic Janus particles of this specification can be easily wetted with a compatible liquid phase (Figure 5). <Test Example 1> Control of particle morphology

When performing expansion and photopolymerization, various forms of particles can be prepared by changing the monomers used in the examples.

In particular, the particles described in the examples were prepared using hexyl acrylate, dodecyl acrylate, tetradecyl acrylate or hexadecyl acrylate as monomers, and their morphology was observed using a bright field microscope. The results show the particles in various forms in Figure 9a (hexyl acrylate), Figure 9b (dodecyl acrylate), Figure 9c (tetradecyl acrylate) and Figure 9d (hexadecyl acrylate) Can be prepared. It is confirmed that when monomers with long alkyl chain length (C>14) are used, sandwich particle morphology can be produced.

At the same time, with the monomer fixed as tetradecyl acrylate, it is also confirmed that various forms of particles can be obtained by swelling and photopolymerization with ethanol/water mixture solvents of different volume ratios.

In particular, when tetradecyl acrylate is used as a monomer and ethanol/water mixture solvents with volume ratios of 4/1, 3/2, 2/3, and 1/4 are used to perform the expansion and photopolymerization reaction, Produce different particle morphologies as shown in Figure 9e (4/1), Figure 9f (3/2), Figure 9g (2/3) and Figure 9h (1/4). <Test Example 2> Control the degree of double-sidedness of Janus particles

It is confirmed that the degree of double-sidedness of Janus particles in this manual can be precisely controlled by controlling the expansion of the particles.

In particular, the degree of duality is defined as D/D ₀ , where D is the shorter diameter of the poly(tetradecyl acrylate) (PTA) part of the particle excluding the polystyrene (PS) part, And D _{0 is} the entire diameter of the particle (see Figure 10c). When D/D ₀ is 0.25, the Janus particle morphology is shown in Figure 10a. And, when D/D ₀ is 0.5, the Janus particle morphology is shown in Figure 10b. As can be seen in Figure 10c, it is confirmed that the degree of double-sidedness can be adjusted by controlling the expansion ratio (PTA/PS, w/w) in the range of 0.25-0.5. When D/D _{0 is} less than 0.25, irregular phase separation is observed. Moreover, when D/D _{0 is} greater than 0.5, the expansion of the monomer cannot proceed uniformly. <Test Example 3> Evaluation of Janus particle interface assembly

In order to prove the self-assembly ability of the Pickering emulsion at the oil-water interface, the interface assembly ability was evaluated.

The microscopic images of the Pickering emulsion prepared in the examples (Figures 11a and 11b) confirm that the Pickering emulsion (oil in water, O/W) is formed, and it has a hydrophilic coating in contact with water Silicon dioxide side and hydrophobic PTA side in contact with oil. Confirm that the degree of double-sidedness D/D ₀ of the second domain relative to the entire Janus particle determines the contact angle at the assembly interface (Figure 12), and confirm that the particle can be determined to be W/O or O/W. When the degree of the double-sidedness is equal to or greater than 0.25 and less than 0.37, the particles are water-in-oil (w/o). When it is equal to or greater than 0.37 and less than 0.75, the particles are in the shape of oil in water (o/w) (Figure 12).

The unique wetting performance of the amphiphilic Janus particles plays an important role in the structural stability of the Pickering emulsion. The adhesion energy (E) of the Pickering emulsion is represented by E=πa ² γ(1 ± cosθ) ² , where a is the radius of the particle, γ is the interfacial tension, and θ is the contact angle. If the radius and interfacial tension of the particles are the same, the adhesion energy will increase when the contact angle is smaller. Therefore, when the degree of duality D/D _{0 is} close to 0.5, a stable Pickering emulsion system can be obtained.

In fact, compared to D/D ₀ = 0.25 (rectangular in Fig. 13), when the degree of double-sidedness D/D ₀ is 0.5 (circular in Fig. 13), the Pickering milk droplets increase with time The durability is significantly improved.

Although the present invention is shown and described with reference to illustrative specific embodiments, those skilled in the art should understand that various forms and details can be changed without departing from the spirit and scope of the present invention as defined by the scope of the appended patent application. .

without

Fig. 1 schematically shows the process of preparing Janus particles as in this specification. Figure 2 shows in sequence the polystyrene synthesized according to this specification, the polystyrene with tetradecyl acrylate monomer swelled therein, and the poly(14) which is formed through photopolymerization and is phase-separated. Alkyl acrylate) is one of Janus particles. Figure 3 shows the process of coating silica nanoparticles on Janus particles as in this specification. Figure 4 shows the Janus particles as in this specification, with 100 nm diameter silicon dioxide particles and 300 nm diameter silicon dioxide particles coated thereon. Figure 5 shows that the amphiphilic Janus particles as in this specification effectively exhibit the wettability of compatible liquids. Figure 6 shows a fluorescence microscopy image and an electron microscopy image. The fluorescence microscopy image shows the polystyrene part and the poly(tetradecyl acrylate) of the Janus particles in one aspect of this specification. In part, the electron microscopic image shows that the Janus particles are spherical. Figure 7 compares the size of polystyrene and Janus particles in one aspect of this specification. Figure 8 shows an X-ray photoelectron spectroscopy (XPS) analysis result of one aspect of this specification, which shows that polyvinylpyrrolidone is covalently bonded to the surface of the polystyrene. Figures 9a-9d show images of particles prepared by changing the alkyl chain length of alkyl acrylates in one aspect of this specification, and Figures 9e-9h show the results of changing the ethanol/water volume ratio in an ethanol/water mixed solvent . Figures 10a-10c show the Janus particles with different degrees of double-sidedness prepared by controlling the expansion ratio in one aspect of this specification. Figures 11a and 11b show microscopic images of Pickering emulsion in one aspect of this specification. Figure 12 shows the relationship between the degree of double-sidedness of Janus particles and the contact angle of the interface in one aspect of this specification. Figure 13 shows the relationship between the degree of double-sidedness of Pickering emulsion droplets and the retention time in one aspect of this specification.

Claims (14)

A Janus particle, comprising: a first domain, which includes polystyrene; and a second domain, which includes poly(tetradecyl acrylate); wherein, a hydrophilicity-inducing group is covalently Bonded to the surface of the first domain polystyrene; wherein the hydrophilicity-inducing group includes one or more selected from the group consisting of poly(vinyl alcohol), polyvinylpyrrolidone and poloxamer ; And wherein, the Janus particles have a degree of double-sidedness of the second domain of 0.25-0.5 relative to the entire particle. The Janus particles described in the first item of the patent application, wherein the first domain includes: a core including polystyrene; and a hydrophilic material coating layer covering the core. As described in the second item of the scope of patent application, the Janus particles, wherein the hydrophilic material coating layer includes a hydrophilic material bonded to the hydrophilicity inducing group, which is covalently bonded to the polyphenylene On the surface of vinyl. The Janus particles described in item 3 of the scope of patent application, wherein the hydrophilic material includes silica nano particles. The Janus particle as described in the first item of the scope of patent application, wherein the Janus particle has a diameter in the range of 1 micron to 100 micron equivalent sphere. An emulsified composition comprising the Janus particles as described in any one of items 1 to 5 in the scope of the patent application. The emulsified composition described in item 6 of the scope of patent application, wherein the emulsified product is Pickering emulsified product. The emulsified composition described in item 6 of the scope of patent application, wherein, when the degree of double-sidedness of the second domain is equal to or greater than 0.25 and less than 0.37 relative to the entire Janus particles, the emulsion is water in oil (w/o ) Emulsion, and when the degree of duality is equal to or greater than 0.37 and less than or equal to 0.5, it is an oil-in-water (o/w) emulsion. A cosmetic composition comprising the emulsified composition as described in item 6 of the scope of patent application. A method for preparing the Janus particles as described in any one of items 1 to 5 in the scope of the patent application, which includes the following processes: (1) Synthesize a polystyrene particle by dispersion polymerization; (2) Disperse the polystyrene particles in a mixed solvent of alcohol and water; (3) Expand the polystyrene particles by absorbing the tetradecyl acrylate monomer into the polystyrene particles by Adding the tetradecyl acrylate monomer to the mixed solvent; and (4) polymerizing the tetradecyl acrylate by photopolymerization and causing phase separation; wherein, the dispersion polymerization in the process (1) It is carried out in the presence of a compound capable of forming a hydrophilicity-inducing group on the surface of the polystyrene particles; wherein the hydrophilicity-inducing group includes one or more selected from poly(vinyl alcohol), polyvinylpyrrolidone and A group consisting of poloxamers; and wherein the Janus particles have a degree of duality of the second domain of 0.25-0.5 relative to the entire particle. The method for preparing Janus particles as described in item 10 of the scope of patent application further includes (5) by bonding silica nanoparticles to the hydrophilicity-inducing group after the process (4) A coating layer of hydrophilic material is formed. The method for preparing Janus particles as described in item 10 of the scope of patent application, wherein the mixed solvent in the process (2) is a ratio of C ₁ -C ₆ alcohol and water in a volume ratio of 4:1-1:4 mixture. The method for preparing Janus particles as described in claim 10, wherein the process (3) is carried out by adding one or more crosslinking agents and photopolymerization initiators. A method for controlling the structure of amphiphilic particles, wherein the amphiphilic particles are prepared by a method including: (1) synthesizing polystyrene particles by dispersion polymerization; (2) in a mixed solvent of alcohol and water (3) Expand the polystyrene particles by absorbing the alkyl acrylate monomer into the polystyrene particles, which is achieved by the alkyl acrylate monomer Adding the mixed solvent; and (4) polymerizing the alkyl acrylate by photopolymerization and causing phase separation, and the particle structure is controlled by one or more of the following: changing the alkyl group in the alkyl acrylate monomer Carbon number; changing the mixed solvent; and changing the expansion ratio of the polystyrene particles; wherein the dispersion polymerization reaction in the process (1) is based on the ability to form hydrophilic inducing groups on the surface of the polystyrene particles In the presence of a compound; wherein the hydrophilicity-inducing group includes one or more selected from the group consisting of poly(vinyl alcohol), polyvinylpyrrolidone and poloxamer; and wherein the swelling ratio is changed so that The degree of double-sidedness of the second domain is 0.25-0.5 relative to the entire amphiphilic particle; wherein the carbon number of the alkyl group varies within the range of 5-20; and wherein the mixed solvent is adjusted in the range of 4:1-1 : The volume ratio of C ₁ -C ₆ alcohol and water changes in the 4 range.

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