KR20160090134A - Preparation method of ZnO nanofiber and uses thereof - Google Patents

Abstract

The present invention provides a zinc oxide nanofiber manufacturing method including: a step of adding polyvinyl alcohol (PVA) to a solvent (first step); a step of adding zinc oxide (ZnO) nanoparticles to the solvent (second step); a step of preparing a mixed solution by mixing the polyvinyl alcohol solution of the first step with the zinc oxide (ZnO) nanoparticles solution of the second step (third step); and skin-core nanofiber preparation through dual nozzle electrospinning of the polyvinyl alcohol (PVA) solution of the first step and the mixed solution of the third step. The present invention also provides a UV-blocking composition containing the zinc oxide nanofiber synthesized according to the present invention as an effective ingredient.

Description

Preparation method of ZnO nanofiber and uses thereof < RTI ID = 0.0 >

The present invention relates to a method for producing PVA / zinc oxide nanofiber and a technique for using the nanofiber prepared by the above method as a sunscreen agent.

Nanoscale materials such as nanospheres, nanorods, nanowires, and quantum dots can exhibit high aspect ratios in volume per volume area, and recently their synthesis method has attracted attention .

Nanoparticles have been synthesized by a variety of methods including chemical precipitation, sol-gel synthesis, and solvent-based solvothermal / hydrothermal reactions. Among them, hydrothermal synthesis and sol- Have a variety of advantages such as low process temperatures, non-catalytic growth, low cost and large scale production capacity. Further, in the case of the hydrothermal method, the shape and size of the nanoparticles can be adjusted according to a suitable reaction temperature, time, and concentration of the precursor.

Interest in zinc oxide nanoparticles having various functional properties such as ultraviolet shielding, conductivity, chemical selectivity, physical stability, and low price among various minerals is increasing, and zinc oxide nanoparticles are widely used in the fields of optical materials, sensors, field effect transistors (fieldeffect transistors), ultraviolet light blocking agents, and blue luminescent devices.

Various zinc oxide nanostructures such as nanowires, nanobelts, nanotubes, nanoflowers and nanorods have already been synthesized, and zinc oxide nanorods and nanospheres have been reported to have inherent properties due to the quantum size effect.

The ultraviolet band consists of three regions, UV-A (315.400 nm), UV-B (280.315 nm) and UV-C (100.280 nm). UV-C is unable to reach the Earth's surface due to stratospheric ozone, but UV-A exposure reduces the immune response of skin cells and produces an aging signal. UV-B exposure is the cause of erythema and skin cancer Is known to be.

The ultraviolet (UV) blocking ability of zinc oxide, which blocks ultraviolet rays that can have a dangerous effect on skin, is a very interesting feature.

Polyvinyl alcohol (PVA) is a good material in polymer compounds because it has unique properties such as non-toxicity, water-solubility, biocompatibility, chemical resistance, hydrophilicity and good fiber forming ability. Such PVA can be used as a drug, a package for polarizing film, a barrier film, a gel for a drug delivery system, and other medical and cosmetic compositions.

Coaxial electrospinning of the skin-core structure is an increasingly popular technology in the fields of biomedical engineering, filtration and dispersion, and microelectronics. Skin-core structure electrospinning networks include capacitors, biosensors , Soft tissue and fuel cell membranes.

Korean Patent Publication No. 10-2013-0070333

The present invention provides a method for producing a skin-core structure of PVA / zinc oxide nanofibers composed of a PVA core layer and a zinc oxide nanoparticle skin layer using dual nozzle electrospinning, and a method for producing a PVA / zinc oxide nano- We want to use the fiber as a sunscreen.

The present invention relates to a process for producing polyvinyl alcohol (PVA) by adding polyvinyl alcohol (PVA) to a solvent (first step); Adding zinc oxide (ZnO) nanoparticles to the solvent (second step); (3) preparing a mixed solution by mixing the polyvinyl alcohol solution of the first step and the zinc oxide (ZnO) nanoparticle solution of the second step (step 3), and mixing the polyvinyl alcohol solution And a third step of preparing a skin-core nanofiber by a double nozzle electrospinning method.

The present invention also provides an ultraviolet screening composition comprising the zinc oxide nanofiber as an active ingredient.

According to the present invention, nanofibers prepared by electrospinning spherical zinc oxide nanoparticles prepared by a sol-gel method together with PVA can be used as a conventional hydrothermal method, such as PVP (polyvinyl pyrrolidone) or CTAB (hexa decyl trimethyl ammonium bromide capping agent and a nanofiber of zinc oxide nanoparticles and a skin composed of a PVA core layer and a colloid zinc oxide skin layer rather than an electrospinning method by a single nozzle - It was confirmed that the blocking effect of PVA / zinc oxide nanofiber of core structure is increased.

 Accordingly, the present invention provides a method for producing PVA / zinc oxide nanofibers, and the PVA / zinc oxide nanofibers synthesized according to the nanofiber manufacturing method of the present invention can be used as an effective ultraviolet screening agent.

Figure 1 shows the results of wide angle X-ray diffraction (WAXD) profiles of zinc oxide (ZnO) nanoparticles prepared with different synthesis methods and capping agents.
FIG. 2 shows SEM images and size distributions of zinc oxide (ZnO) nanoparticles; FIG. (a) is a hydrothermally synthesized zinc oxide (ZnO), (b) is zinc oxide (ZnO-HPPVP) hydrothermally synthesized by using PVP as a capping agent, and (c) Zinc (ZnO-HP-CTAB), and (d) is the result of zinc oxide (ZnO-SG) synthesized by sol-gel.
FIG. 3 is a TEM image of zinc oxide (ZnO) nanoparticles, in which (a) is zinc oxide (ZnO) synthesized by a hydrothermal method, (b) is zinc oxide (ZnO) synthesized by hydrothermal method using PVP as a capping agent, (ZnO-HP-CTAB) synthesized by hydrothermal method using CTAB as a capping agent, and (d) is a result of zinc oxide (ZnO-SG) .
FIG. 4 is a FE-TEM image of colloidal zinc oxide (ZnO) nanoparticles synthesized by a sol-gel method.
Fig. 5 shows the SEM image and diameter distribution of the nanofibers synthesized with PVA / ZnO. Fig. 5 (a) shows the PVA / ZnO nanofiber, (C) is nanofiber synthesized with zinc oxide (ZnO-HP-CTAB) capped with PVA / CTAB, and (d) is a nanofiber synthesized with PVA / sol- (ZnO-SG).
FIG. 6 is a TEM image of a nanofiber synthesized with PVA / ZnO, wherein (a) is a PVA / ZnO nanofiber and (b) is a nanofiber synthesized from zinc oxide (ZnO-HP-PVP) capped with PVA / (C) is nanofiber synthesized with PVA / CTAB-capped zinc oxide (ZnO-HP-CTAB), and (d) is zinc oxide (ZnO-SG) prepared by the PVA / It is the result of synthesized nanofiber.
FIG. 7 shows the UV transmittance of nanofibers synthesized with PVA / ZnO. FIG. 7 (a) shows the UV spectrum, FIG. 7 (b) shows the UV transmittance according to the mold shape at 400 nm, c) shows the UV transmittance according to the zinc oxide particle content.

The present invention relates to a process for producing polyvinyl alcohol (PVA) by adding polyvinyl alcohol (PVA) to a solvent (first step); Adding zinc oxide (ZnO) nanoparticles to the solvent (second step); (3) preparing a mixed solution by mixing the polyvinyl alcohol solution of the first step and the zinc oxide (ZnO) nanoparticle solution of the second step (step 3), and mixing the polyvinyl alcohol solution And a third step of preparing a skin-core nanofiber by a double nozzle electrospinning method.

More specifically, the zinc oxide nanoparticles may be colloidal zinc oxide nanoparticles having a size of 5 to 15 nm synthesized by a sol-gel method.

According to one embodiment of the present invention, in the case of the zinc oxide nanoparticles synthesized by the conventional hydrothermal synthesis method as shown in FIGS. 2 and 3 and the zinc oxide nanoparticles hydrothermally synthesized together with the PVP or CTAB capping agent, While nanoparticles were identified, in the case of colloidal zinc oxide nanoparticles synthesized by the sol-gel method, spherical nanoparticles smaller in size than the zinc nanoparticles synthesized with the capping agent were identified , It was confirmed that the dispersion effect of the colloidal zinc oxide nanoparticles was excellent as shown in FIG. 6, and the PVA / ZnO nanofiber synthesized by using the colloidal zinc oxide nanoparticles as shown in FIGS. 7 (a) and 7 ZnO nanofibers synthesized by using zinc oxide nanoparticles synthesized by hydrothermal synthesis and pine.

The polyvinyl alcohol solution may be contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the solvent, and the zinc oxide (ZnO) nanoparticle solution may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the solvent. no.

Also, the voltage used in the electrospinning of the present invention may be 5 to 30 kV, the scanning speed may be 0.5 to 5 mL / h, and the average diameter of the double nozzles used in the electrospinning may be 0.30 to 0.50 mm And the inner and outer diameters of the skin may be 0.60 to 1.50 mm and 0.90 to 1.65 mm, respectively, more preferably the voltage used for electrospinning is 15 kV, the scanning speed may be 1 mL / h, The average diameter of the double nozzles used in electrospinning may be 0.33 mm in core diameter and 0.63 mm and 1.07 mm in inner and outer skins, respectively, but is not limited thereto.

Therefore, in the skin-core structure nanofiber of the present invention, zinc oxide nanoparticles form a skin layer, and polyvinyl alcohol (PVA) can form a core layer.

According to another embodiment of the present invention, the nanofiber synthesized from PVA (skin) / zinc oxide (core) and the PVA / ZnO nanofiber synthesized from a single nozzle are mixed with zinc oxide (skin) / The nanofiber synthesized from zinc oxide (skins) / PVA (core) showed a UV blocking ability that was increased by 20% or more than that of the nanofiber synthesized with PVA (core).

Accordingly, the present invention can provide an ultraviolet screening composition containing zinc oxide nanofibers produced according to the present invention as an active ingredient, and the ultraviolet screening composition can be used as a mask, a mask pack, and a cosmetic composition for ultraviolet screening, But is not limited thereto.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are intended to illustrate the contents of the present invention, but the scope of the present invention is not limited to the following examples. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

< Example  1> Material

Zinc nitrate (Zn (NO ₃ ) ₂ ), sodium hydroxide (NaOH), zinc acetate (Zn (O ₂ CCH ₃ ) ₂ ) and lithium hydroxide (LiOH) were purchased from Duksan, Polyvinyl alcohol (PVA) was purchased from DC Chemical (Seoul, Korea) and the number average degree of polymerization (Pn) and saponification degree (DS) were 1700 and 99.9%, respectively.

Poly vinyl pyrrolidone (PVP) was purchased from Wako Pure Chemical Industries (Japan), and hexadecyl trimethyl ammonium bromide (CTAB) was purchased from Tokyo Chemical Industry Co., Ltd. Respectively. Absolute ethanol was also obtained from Daejung Chemicals & Metals Co., Ltd. All of the above materials were used without further purification.

Zinc oxide (ZnO) nanoparticles were synthesized by hydrothermal method using secondary distilled water, and colloidal ZnO was prepared using anhydrous ethyl alcohol.

< Example  2> Synthesis of zinc oxide nanoparticles

1. hydrothermal synthesis ( hidrothermal method ) Of zinc oxide ZnO ) Synthesis of nanoparticles

To synthesize zinc oxide nanoparticles, 0.1M zinc nitrate and 0.2M sodium hydroxide were mixed and continuously stirred at room temperature for 2 hours.

The mixed solution was transferred to a Teflon beaker and then heated to 200 DEG C for 2 hours in an autoclave. After the reaction, the autoclave was cooled to room temperature and zinc oxide particles were precipitated. The precipitate was washed several times with Na ⁺ and NO ₃ ^- removed distilled water, dried at 100 ° C. for one day, and then the dried powder was pulverized with a mortar and mortar.

In order to change the size and shape of the zinc oxide nanoparticles, a capping agent such as PVP and CTAB was added. First, 0.05 wt% of PVP or CTAB was mixed with a zinc nitrate solution, and the zinc oxide nanoparticle synthesis method Zinc oxide nanoparticles were prepared by the same procedure as described above.

2. Sol-gel synthesis ( left - come synthesis ) Of colloidal zinc oxide ZnO ) synthesis

To prepare colloidal zinc oxide nanoparticles using sol-gel synthesis, a reflux condensation method was used, and zinc acetate and anhydrous ethyl alcohol were used without further purification.

First, a 1 L round bottom distillation flask was charged with 0.5 L of anhydrous ethyl alcohol and 0.1 mol of zinc acetate, the distillation flask was placed in a condenser, and the solution was refluxed at 80 ° C for 180 minutes. During the reflux reaction, a white condensate was collected and 0.2 L of the reactant (precursor) and 0.3 L of condensate were obtained in the finishing step, and the precursor thus obtained contained zinc ethoxide type compound.

0.2 L of the precursor was diluted with 0.5 L of anhydrous ethyl alcohol and 0.07 mol lithium hydroxide powder was added to the precursor to a final lithium hydroxide concentration of 0.14M.

The hydrolysis reaction of the mixture was accelerated using an ultrasonic bath and the hydrolysis reaction was maintained at room temperature (maintained for about 1 hour) until no more lithium hydroxide powder was found.

The zinc oxide colloidal suspension thus obtained was passed through a glass fiber filter (0.1 μm) to remove dust and remaining undissolved lithium hydroxide by filtration.

Finally, the colloid was concentrated from 0.5 M to 0.5 M at 30 ° C using a vacuum rotary condenser.

The above-described zinc oxide nanoparticle synthesis method and capping agents were summarized as shown in Table 1.

sample Synthesis method Capping agent ( capping agent ) ZnO Hydrothermal method - ZnO / PVP Hydrothermal method PVP ZnO / CTAB Hydrothermal method CTAB ZnO-SG Sol-gel -

< Example  3> ZnO / PVP Of Nanofibers Synthesized with

Nanofibers were fabricated using electrospinning consisting of metal needles, syringe pumps, high-voltage power supplies capable of delivering tens of kilo-volts, and spinnerets and grounded collectors.

Electrospinning applies a high voltage to the polymer fluid to induce electrical charge in the fluid, and when the charge reaches a critical amount, fluid ejection occurs from the droplet at the tip of the needle, and the electrospinning ejection is directed toward the low potential of the grounded collector To form a Taylor cone.

The average diameter of the core cylinder was 0.33 mm, the inner and outer diameters of the skin annulus were 0.63 and 1.07 mm, respectively, and the land length was 7 mm.

First, 9 wt% PVA was dissolved in distilled water at 90 ° C for 2 hours, and 1 wt% of zinc oxide (ZnO) nanoparticles synthesized by another method in Example 2 was dispersed in distilled water for 2 hours at room temperature And then mixed with the PVA solution. The mixed PVA / ZnO solution and the PVA solution were transferred to two 10 mL syringes, and the PVA / ZnO solution was used as the skin layer of the nanofiber and the PVA solution was used as the core of the nanofiber.

The anode of the high-voltage power supply was fixed to a metallic double nozzle, and each skin and core solution was electrospun at a rate of 1 mL / h at room temperature toward the collector. As shown in Table 2, the voltage applied to the electrospinning was 15 kV, and the distance from the needle tip to the collector was 12 cm.

Polymer solution The solvent Distilled water PVA concentration 9 wt% Electric radiation

Applied voltage 15 kV speed 1 ml / h Distance from tip to collector 12 cm

      As a result, the nanofibers were collected on a steel drum covered with an aluminum foil.

< Example  4> Confirmation of nanoparticles and electrospun nanofibers

1. Identification of nanoparticles and electro-dispersive nanofibers

(FE-SEM, S-4100, Hitachi Co., Japan) after platinum coating to confirm the morphology of nanoparticles and electrospun nanofibers The average diameter and the thickness of the nanoparticles were confirmed by a SEM image of the sample, and a transmission electron microscope (TEM, H-7600, Hitachi Co., Japan) and a field-emission transmission electron microscope ; FE-TEM, S-4800, Hitachi Co., Japan).

The crystal structure of zinc oxide nanoparticles was confirmed at 3 ° / min scan rate using wide-angle X-ray diffraction (WAXD, D / MAX-2500, Rigaku, Tokyo, Japan) (UV-vis spectroscopy, Carry 5000, Agilent Co., USA) was used to confirm the UV transmittance of the nanofiber network.

2. Zinc oxide ( ZnO ) Identification of nanoparticle morphology

Zinc oxide synthesized by hydrothermal synthesis of Example 2, zinc oxide synthesized with PVA and CTAB capping agent, and colloid zinc oxide synthesized with sol-gel were identified as shown in FIG.

As a result of the wide angle X-ray diffraction (WAXD) profile of the zinc oxide nanoparticles, a slight change in the peak intensity of the zinc oxide nanoparticles was found, but all showed typical zinc oxide crystal peaks. (WAXD) pattern showed that the diffraction planes of 100, 002, 101, 102, 110, 103 and 112 of zinc oxide crystals were 31 °, 34 °, 36 °, 48 °, 57 °, 63 ° and 68 ° Which was identified as a characteristic peak.

Also, referring to FIG. 1, it was confirmed that the intensity of the diffraction peak was decreased by the addition of the capping agent because the degree of crystallization was decreased by the addition of the capping agent. As compared with pure zinc oxide, , While small particles were found to be capable of affecting the rate of nucleation by maintaining the growth rate. It was confirmed that colloidal zinc oxide exhibited lower broad-angle X-ray diffraction (WAXD) strength and broader peak than other samples, and it was confirmed that colloidal zinc oxide has a low crystallinity and a very small crystal size.

In addition, SEM images of zinc oxide nanoparticles produced by different capping agents and synthetic methods and particle size distribution of nanoparticles were confirmed. In order to confirm the consistency of the produced nanoparticles and the statistical significance of the data, repeated experiments were carried out three times and the samples at different positions were analyzed by FE-SEM.

As a result, the size distribution was confirmed as shown in the right graph of FIG. 2, and both types of nanoparticles were confirmed.

Referring to Figs. 2 (a) to 2 (c), the zinc oxide synthesized by the hydrothermal precipitation method generally showed a hexagonal rod shape. The diameter of the pure zinc oxide of FIG. 2 (a) was 90-120 nm, and the zinc oxide containing PVP of FIG. 2 (b) formed nanorods of 60-90 nm diameter.

Since PVP is a water-soluble polymer composed of N-vinylpyrrolidone monomers, the addition of PVP can protect nanoparticles from agglomeration, since they can form coordinate bonds with zinc ions in particle growth.

As shown in FIG. 2 (c), the zinc oxide containing CTAB exhibited a diameter of 40-70 nm, and a relatively thin and uniform structure was confirmed as compared with zinc oxide containing PVP.

The cationic surfactant, CTAB, is completely ionized in aqueous solution, leading to positive aminohead group formation. Therefore, it was confirmed that when CTAB is added together with zinc oxide, small zinc oxide nanoparticles are formed due to induction of bonding with one or more head groups at the interface of micelles through electrostatic interaction and structural complementation .

From these results it was confirmed that the reduction of the nanorod size was indicated by the capping agent.

On the other hand, the colloid zinc oxide produced by the sol-gel synthesis method was confirmed to be mostly spherical particles as shown in Fig. 2 (d). The presence of many nuclei prevents the preferential growth along the c-axis because it can add a limited amount of zinc ions onto the existing growth particles as monomers. Thus, it was confirmed that the colloidal zinc oxide grows in a relatively same axis, and statistical analysis confirmed that the colloidal zinc oxide particle size was between 5 nm and 15 nm.

In addition, a sample was prepared in which droplets of a diluted suspension of each sample were placed on a carbon-coated copper grid containing holes and the solvent could evaporate, and then the nanostructures of the zinc oxide nanoparticles And morphological aspects were confirmed.

As a result, it was confirmed that the pure zinc oxide produced by hydrothermal precipitation and the zinc oxide crystal containing the capping agent were rod-shaped as shown in Figs. 3 (a) to 3 (c). In addition, the diameter of the nanorods was found to be relatively smaller than the diameter of the nanorods of pure zinc oxide.

Also, it was confirmed that the colloidal zinc oxide was spherical as shown in Fig. 3 (d).

An FE-TEM image of the colloidal zinc oxide and the resulting fast Fourier transform (FFT) pattern were confirmed.

As a result, as shown in FIG. 4, the particles of the colloidal zinc oxide were found to be rough spherical, and it was confirmed that the particles of the colloid zinc oxide were a single crystal having many faces through the lattice pattern. It was also confirmed that the particle size was between 5 nm and 10 nm.

The FFT pattern of FIG. 5 (b) confirmed that the 110 and 002 planes of the zinc oxide nanoparticles were confirmed, and it was confirmed that the D-spacing of the 002 plane from the FFT image was 0.25 nm.

3. PVA / With zinc oxide (ZnO)  Identify Configured Nanofibers

Nanofibers electrospun with PVA (core) / ZnO (skin) were identified using different zinc oxide nanoparticles synthesized in Example 3.

As a result, all of the nanofibers were randomly arranged without a clear arrangement, and the nanofiber diameters ranged from 200 nm to 500 nm as shown in FIG. 5, which is an SEM image of nanofibers electrospun with PVA (core) / ZnO Respectively.

Also, the surface composed of the nanofibers was soft, and it was confirmed that the zinc oxide nanoparticles containing the PVA as a core are good bonds.

6 (a) to 6 (c), which are TEM images, it was confirmed that large zinc oxide nanoparticles in the nanofiber composed of PVA / ZnO exhibited agglomeration tendency. On the other hand, as shown in FIG. 6 (d) The zinc nanoparticles were better dispersed than the pure zinc oxide, and it was confirmed that the spherical shape of the zinc oxide was maintained well in the synthesized nanofiber

From the above results, it was confirmed that the small particle size in the PVA polymer matrix is related to the good nanoparticle distribution.

Next, the UV transmittance spectra of nanofibers synthesized with PVA / ZnO were observed in the wavelength range from 200 nm to 600 nm.

As a result, when the zinc oxide nanoparticles were added to the PVA as shown in FIG. 7 (a), the UV transmittance was considerably reduced, and these results were confirmed by the fact that the oxidation was observed within the UV-B and UV-A spectral range (315 nm to 400 nm) Lt; RTI ID = 0.0 &gt; reduced particle size of zinc. &Lt; / RTI &gt;

Zinc oxide nanoparticles can absorb UV-A and UV-B radiation. Therefore, UV blocking ability of nanofiber synthesized with PVA / ZnO was confirmed by comparing the UV transmission spectra of PVA / ZnO nanofibers synthesized by the four methods.

As a result, it was confirmed that the UV blocking ability was increased in the order of zinc oxide (ZnO) / zinc oxide (ZnO) / PVP (zinc oxide) / CTAB (colloidal zinc oxide).

From the above results, it was confirmed that the size and distribution of zinc oxide nanoparticles affected the UV blocking ability.

7 (b) is a graph comparing the UV transmittance (400 nm) of the PVA / ZnO nanofibers synthesized by changing the nozzle type and the skin-core position of the zinc oxide particles, (Core) nanofibers exhibited excellent UV blocking ability, while PVA / ZnO nanofibers synthesized from PVA (skin) / zinc oxide (core) nanofibers and single nozzle synthesized zinc oxide (skin) / PVA (core) nanofibers.

From the above results, it was confirmed that UV blocking is more effective when the zinc oxide nanoparticles are located on the skin layer.

Next, the UV blocking effect of nanofibers synthesized with various amounts of zinc oxide nanoparticles was confirmed.

As a result, it was confirmed that the UV blocking effect of the PVA nanofiber composed of the colloidal zinc oxide was superior to other nanoparticles of the same amount as in FIG. 7 (c). Also, the transmittances of 1 wt% colloidal zinc oxide and 1.5 wt% colloidal zinc oxide were 5% and 1%, respectively.

From the above results, it is confirmed that when small-sized nanoparticles are well distributed, it is effective for UV shielding, so that colloidal zinc oxide having a small size can effectively block UV even in a small amount.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (8)

Adding polyvinyl alcohol (PVA) to the solvent (first step);
Adding zinc oxide (ZnO) nanoparticles to the solvent (second step);
(3) mixing the polyvinyl alcohol solution of the first step and the zinc oxide (ZnO) nanoparticle solution of the second step to prepare a mixed solution; and
Wherein the nanofibers of the skin-core structure are prepared by the double-nozzle electrospinning of the polyvinyl alcohol (PVA) solution of the first step and the mixed solution of the third step. The method according to claim 1, wherein the zinc oxide nanoparticles are colloidal zinc oxide nanoparticles having a size of 5 to 15 nm synthesized by a sol-gel method. The method according to claim 1, wherein the polyvinyl alcohol solution is contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the solvent. [2] The method of claim 1, wherein the zinc oxide (ZnO) nanoparticle solution is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the solvent. The method of claim 1, wherein the voltage used for electrospinning is 5 to 30 kV and the scanning speed is 0.5 to 5 mL / h. [3] The method according to claim 1, wherein the average diameter of the double nozzles used in the electrospinning is 0.30 to 0.50 mm in core diameter and 0.60 to 1.50 mm and 0.90 to 1.65 mm in the inner and outer diameters of the skins, Method of manufacturing nanofibers. [Claim 2] The method according to claim 1, wherein the skin-core nanofibers comprise zinc oxide nanoparticles as a skin layer and polyvinyl alcohol (PVA) as a core layer. A sunscreen composition comprising zinc oxide nanofibers prepared according to any one of claims 1 to 7 as an active ingredient.

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