KR101691039B1

KR101691039B1 - 3-dimenstinal nanofiber membrane and Method of manufacturing the same using liquid collector

Info

Publication number: KR101691039B1
Application number: KR1020150073842A
Authority: KR
Inventors: 박장웅; 현병관; 안병완; 지상윤; 유혜련; 정해원
Original assignee: 국방과학연구소
Priority date: 2015-05-27
Filing date: 2015-05-27
Publication date: 2016-12-29
Also published as: KR20160139264A

Abstract

The present invention relates to a three-dimensional porous nanofiber membrane, and more particularly, to a three-dimensional porous nanofiber membrane manufactured by spinning into a liquid collector using electrospinning, and a method for producing the same.
According to the present invention, nanofibers produced after the electrospinning process can be stacked together and the functional material can be inserted therein, so that the electrical, mechanical and / or optical properties can be improved while having porosity.

Description

(3-dimenstinal nanofiber membrane and method of manufacturing the same using liquid collector)

The present invention relates to a three-dimensional nanofiber membrane, and more particularly, to a three-dimensional porous nanofiber membrane manufactured by spinning into a liquid collector using electrospinning, and a method of manufacturing the same.

Recently, as the importance of nanofibers becomes more important, the research and development of nanofibers by electro-spinning is actively carried out.

Nanofibers are materials that exhibit high performance throughout the industry, and research and development using nano materials such as filters using nonwoven fabrics, miniaturization and high functionality of electronic devices, and biomaterial use are being actively developed.

Electrospinning is carried out by applying a high voltage of positive (+) or negative (-) of several thousands to tens of thousands of volts to charge the polymer solution, discharging the charged solution to the air layer through a capillary nozzle, Is a spinning method in which microfine fibers having a diameter of several tens of nanometers to several thousands of nanometers are produced through stretching and branching between adjacent filaments in an air layer.

At this time, the microfine fibers charged with (+) or (-) charge are grounded to have a potential difference or integrated on a collector charged to the opposite polarity, thereby producing a porous film of a web structure.

Korean Patent No. 10-0470314 entitled "Composite Membrane for Electrochemical Device, Method for Producing the Same, and Electrochemical Device Including the Same" discloses a porous membrane having such a web structure.

The present invention provides a composite membrane made of nanofibers, which can greatly improve the performance of a battery when used in an electrochemical device, and enables manufacture of a battery having a high mechanical strength.

However, there is a limitation in simply improving the performance of the porous membrane because it is not possible to use a method of simply bonding a polymer material.

1. Korean Patent No. 10-0470314 2. Korean Patent Publication No. 10-2011-0129106

1. Kwak, KS et al., "Preparation and Characterization of Electrospun Nanofiber Ion Exchange Membrane for PEMFC Sulfonated Poly (ether ether ketone) (SPEEK)" Polymer 36 권 2 (March 2012) pp.155-162.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a method for manufacturing nanofibers by combining an electrospray process or a spray process with an electrospinning process capable of producing nanofibers, Dimensional porous nanofiber membrane and a method for manufacturing the porous nanofiber membrane using a liquid collector capable of directly improving the performance of the membrane by introducing impurities such as phosphorus,

In order to achieve the above-mentioned object, the present invention relates to an electrospinning process or a spray process, which is combined with an electrospinning process capable of producing nanofibers, to form functional particles of graphene, cellulose, etc. To provide a three-dimensional porous nanofiber membrane capable of directly improving the performance of the membrane.

The three-dimensional porous nanofiber membrane may be a three-

(a) preparing a polymer solution by mixing a powdery polymer material and a functional material into a solvent capable of dissolving the polymer material;

(b) electrospinning the polymer solution to produce nanofibers; And

(c) accumulating the nanofibers on a liquid collector to produce a three-dimensional nanofiber membrane, wherein the functional material is selected from the group consisting of metal nanomaterials, carbon nanomaterials, cellulose, acrylic, epoxy, chitosan, graphene ), reduced graphene oxide (rGO), and carbon nanotubes (CNT). The present invention also provides a method for fabricating a three-dimensional nanofiber membrane.

The step (b) includes the steps of: (b-1) applying a voltage to a spinneret for spinning the polymer solution; And (b-2) radiating the polymer solution from the spinning nozzle to the liquid collector.

According to another aspect of the present invention, there is provided a method for preparing a polymer solution, comprising: (a) dissolving a polymer material in a solvent to prepare a polymer solution; (b) preparing a mixed solution containing a functional material; (c) forming a nanofiber web by electrospinning the polymer solution by applying a high voltage to the polymer solution, and forming a spray of the mixed solution by electrostatic atomization by applying a voltage lower than the high voltage to the functional material; (d) inserting the functional material into the nanofibers to form nanofibers; And (e) collecting the nanofibers from a liquid collector to produce a porous three-dimensional nanofiber membrane.

In addition, the method for fabricating the three-dimensional nanofiber membrane may further include: (e) after the step (f), stabilizing the porous three-dimensional nanofiber membrane; And (g) carbonizing the porous nanofiber membrane by heating at 800 to 1200 占 폚 in an inert atmosphere.

At this time, the liquid collector may include water and ethanol.

Here, it is characterized in that ethanol is contained in an amount of 25 wt% or more, and the thickness of the nanofibers to be deposited according to the spinning time is 100 μm or more per hour.

The solvent may also be selected from the group consisting of Alkanes containing hexane, Aromatics containing toluene, ethers containing diethyl ether, chloroform, Alkyl halides, Esters, Aldehydes, Ketones, Amines, Alcohols, Amides, Carboxylic acids, Carboxylic acids, ), And water.

In addition, the polymer material may be in powder form.

In addition, the polymer material may be at least one selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyurethane, polyether urethane, cellulose acetate, cellulose acetate (PMA), polyvinyl acetate (PVAc), polyacrylonitrile (PAN), polyperfuryl alcohol (PPFA), polystyrene, polyethylene oxide (PEO), polypropylene (PPO), polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, polyamide, polylactide, polyglycolide, polyglycolide, polycaprolactone, Polybutylene terephthalate, polybutylene terephthalate, polybutylene terephthalate, polybutylene terephthalate, polybutylene terephthalate, A polyvinylidene fluoride copolymer, a polylactide copolymer, a polyglycolide copolymer, a polycaprolactone copolymer, a polytrimethylene carbene carbonate copolymer, a polypropylene oxide copolymer, , A polyamino acid copolymer, and a polyorthoester copolymer.

The functional material may include at least one selected from the group consisting of a metal nanomaterial, a carbon nanomaterial, cellulose, acryl, epoxy, chitosan, rGO, CNT, metal nanowires, and metal nanoparticles.

At this time, the reduced rheological oxide (rGO) has a sheet resistance of 1000? / Sq or less.

The metal nanomaterial may be at least one selected from the group consisting of Ag, Cu, Co, Sc, Ti, Cr, Mn, (Ni), Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, (Pd), cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Hg), lanthanide, actinoid, silicon, germanium, tin, arsenic, antimony, bismuth, gallium Ga), and indium (In).

In addition, the carbonized porous three-dimensional nanofiber membrane may have a sheet resistance of 20? / Sq or less.

The electrospinning may be coaxial electrospinning, and the nanofibers may be coated with nanofibers of polymer fibers on the surface of the liquid crystal solution.

On the other hand, another embodiment of the present invention includes a graphene powder including nanofibers electrospun from a polymer material and electrostatically sprayed at the same time during the electrospinning, wherein the electrostatically sprayed graphene powder Dimensional nanofiber membrane is filled with the electrospun nanofiber and has a thickness of 300 m or more.

At this time, the web including the nanofibers may include graphene sprayed in a spray manner to control the electrical properties of the web.

According to the present invention, nanofibers produced after the electrospinning process can be stacked together and the functional material can be inserted therein, so that the electrical, mechanical and / or optical properties can be improved while having porosity.

As another effect of the present invention, it is possible to provide a liquid collector having a low surface tension capable of overcoming the super-hydrophobicity of nanofibers produced through an electrospinning process, thereby producing a functional membrane applicable to a solar cell or the like .

1 is a conceptual diagram schematically showing a device in which an electrospinning process is generally performed.
FIG. 2 is a conceptual diagram showing a process in which a polymeric spinning fiber is formed into a spinning fiber after forming a Taylor cone.
3 is a conceptual diagram schematically showing an apparatus for manufacturing a membrane using electrospinning according to an embodiment of the present invention.
FIG. 4 is a conceptual diagram schematically illustrating a process of inserting a functional material into or on a surface of an electrospun nanofiber according to an embodiment of the present invention. Referring to FIG.
5A and 5B are conceptual diagrams illustrating a process in which optical characteristics are changed in relation to the transmittance of a material.
FIG. 6 is a graph showing the degree of scattering according to the size of inner particles, and FIG. 7 is a graph showing the difference in degree of scattering when scattering occurs at a wide angle and a narrow angle.
FIG. 8 is a photograph showing the phenomenon that occurs when the nanofibers are electrospun using poly (ε-carprolactone) as a polymer material and immersed in ethanol and distilled water.
9 is a view showing the accumulation process of nanofibers according to the addition of ethanol.
10 is a graph showing the thickness of the membrane according to the electrospinning time according to Comparative Examples and Examples.
FIGS. 11 and 12 are photographs showing an improvement in electrical characteristics when rGO is electrostatically sprayed, respectively. FIG. 11 is a photograph showing that the electrospun nanofibers are improved in electrical properties through stabilization and carbonization processes.
13 is a flowchart illustrating a process of manufacturing a membrane according to an embodiment of the present invention.
FIG. 14 is a flowchart showing a manufacturing process of a membrane according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, as well as the invention achieving them, will be apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. It is defined only to give the possessor a complete description of the scope of the invention. The size and relative size of each layer and regions in the figures may be exaggerated for clarity of illustration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for fabricating a three-dimensional porous nanofiber membrane and a liquid collector according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram schematically showing a device in which an electrospinning process is generally performed. 1, when the polymer solution 10 is charged into the syringe pump 20 and a voltage is applied to the spinning nozzle 30, the polymer solution 10 becomes fibrous, .

At this time, a taylor cone 40 may be formed in the process of discharging the polymer solution 10 to the outside air through the spinning nozzle 30.

In FIG. 1, when an electric force is applied to the polymer solution (10) melted or dissolved in a solvent, the charge is induced to the surface of the polymer liquid that has been formed at the tip of the spinneret by the surface tension and the force due to the mutual repulsive force Which occurs in the opposite direction to the surface tension.

FIG. 2 is a conceptual diagram showing a process in which a polymeric spinning fiber is formed into a spinning fiber after forming a Taylor cone. Referring to FIG. 2, when the voltage is 0, the angle formed between the polymer liquid 220 and the surface of the polymer liquid increases as V increases in the shape of the ellipse 210.

At this time, when the threshold voltage or more is exceeded beyond the surface tension of the polymer solution droplet, the charged polymer solution jet 230 is discharged by the electrical repulsive force. The jet is thinned by stretching and / or stretching while flying through the air, and the solvent is volatilized to produce a nonwoven web in which the nanofibers 50 are laminated on a collector 60. The electrospinning web thus formed can have breathability due to a number of micro-pore structure, and is formed of a fiber aggregate having a nanoscale diameter, so that it has a characteristic of being flexible, ultra-thin and light-weight.

Fibers made with such electrospinning technology have recently undergone intensive scientific research due to a wide range of potential applications, including filtration, optical fibers, protective fabrics, drug delivery systems, tissue engineering scaffolds, and gas separators.

In addition, the fiber thus produced has a diameter of several micrometers to several nanometers in accordance with the production conditions, has a very large surface area per unit mass, and is flexible, which suggests the possibility of an adsorbent. In addition, a large amount of fiber voids and a large dispersion of external stresses indicate the possibility of an efficient adsorption membrane in which the flow rate is good at the time of adsorption and the structure is not broken at the flow rate.

3 is a conceptual diagram schematically showing an apparatus for manufacturing a membrane using electrospinning according to an embodiment of the present invention. In addition, FIG. 3 is an illustration showing coaxial electrospinning for a liquid crystal.

Referring to FIG. 3, when the coaxial electrospinning technique is used, the surface of the liquid crystal solution 45 is coated with nanofibers 50, which are polymer fibers. At this time, the polymer solution becomes a (+) charged state.

Electrospinning technology has the disadvantage that only the polymer solution is spinnable. In the case of coaxial electrospinning technology, however, even if the internal solution is a material (liquid crystal, metal, ceramic, etc.) Radiation is possible.

Thus, the web of the nanofibers electrospun can be improved even by a method other than the insertion of a substance that is not electrospun into the inside of the electrospun material.

One such technique is a technique of combining electrospinning and electrostatic spray, which will be described later. The electrostatic atomization during the electrospinning process can improve the physical properties of the electrospun nanofiber.

FIG. 4 is a conceptual diagram schematically illustrating a process of inserting a functional material into or on a surface of an electrospun nanofiber according to an embodiment of the present invention. Referring to FIG. Referring to FIG. 4, electrospinning and spraying can be simultaneously performed. Such a spray may be a spray coating or electrostatic spray.

At this time, when coating is performed through electrostatic spraying, electrostatic spraying process can be performed by not only the electrospinning but also the simple adjustment of the voltage during the electrospinning.

More specifically, an electric field is formed by a potential difference generator (not shown) connected to the syringe pump 20 carrying the graphene solution, and the graphene solution sprayed from the syringe pump 20 is supplied to the electrospinning device (Not shown) to the inside of the electrospun nanofiber 50.

Alternatively, the nanofibers can be coated on the nanofiber web using a syringe pump 20 on which the solution carrying the graphene 70 is carried. In this way, the electrical properties of the nanofiber membrane can be improved by coating the surface of the nanofiber.

When the graphene 70 is dispersed in the polymer resin, it is difficult for the graphene 70 to uniformly disperse in the polymer resin. As a method of fusing an electrospray method with an electrospinning method to a dispersed solution of graphene 70 having poor dispersibility as described above and mixing the graphene 70 into the nanofibers 50, 50 can be improved. A flow chart showing the manufacturing process of the nanofibers 50 in which the graphenes 70 are mixed is shown in Fig. 14 will be described later.

4, when the polymer solution 10 is contained in the syringe pump 20, a high voltage is applied between the spinneret 30 and the liquid collector 60 to form the nanofibers 50 An electrospinning process may be carried out. The nanofibers 50 produced through the electrospinning process may be mixed with the graphene powder 70 discharged through the electrostatic spraying process while being radiated to the collector 60.

More specifically, an electric field is generated by a potential difference generator (not shown) connected to the syringe pump 20 on which the graphene solution is carried, and the graphene pump 20 and the graphene solution sprayed from the spray nozzle 35 Can be introduced into the interior of the electrospun nanofiber by the electrospinning device.

Through the above mixing process, the graphene powder 70 can be included in the nanofibers 50 which are radiated from the polymer solution 10 and branched, thereby improving the physical properties of the nanofibers 50.

The graphene solution and the polymer solution use different syringe pumps. Further, for the purpose of discrimination, the polymer solution (10) is pushed by using the first syringe pump, and electrospinning is performed to make the nanofibers (50). On the other hand, the solution of the graphene 70 is pushed using the second syringe pump so as to be electrostatically sprayed.

Various functional materials may be incorporated in addition to the graphenes 70 described above. These functional materials include, for example, reduced graphene oxide (rGO), carbon nanotube (CNT), metal nanowires, metals such as metal nanoparticles, and carbon-based nanomaterials Can be selected.

The optical properties of the nanofibers 50 can be improved as another functional material. Figures 5 to 7 show optical properties of various factors related to light scattering among various factors related to the transmittance of a material.

5A and 5B are conceptual diagrams illustrating a process in which optical characteristics are changed in relation to the transmittance of a material. Referring to FIG. 5A, when light passes through a material having a homogenous property and a low surface roughness, incident light is transmitted except for components reflected and absorbed.

On the other hand, as shown in FIG. 5B, when light passes through a medium containing a foreign substance or a substance having a high surface roughness, scattering occurs inside. When the incident light is reduced in transmittance due to the scattering component, it is difficult to apply it as an optical material.

Here, surface roughness refers to the degree of fine irregularities that occur on the surface when machining a metal surface. Also known as surface roughness. The surface roughness is caused by the tools used for machining, the suitability of the processing method, scratches on the surface, and rust. In order to show the degree of roughness, the surface is cut into a plane perpendicular to it, and its cross-section is taken as a curve, taking the height from the lowest point to the highest point of this curve, which is called the maximum value roughness . This is denoted by R _max or R.

A refractive index can be obtained without taking into consideration other factors such as absorption of energy of a specific wavelength band in the material, occurrence of reflection, refraction, scattering depending on roughness of the surface, The refractive index should be the same, so that there is no loss of permeability.

For example, nanofibers, which are polymers, and cellulose, an additive material, must have the same refractive index to reduce the loss of permeability. In addition, the degree of scattering depending on the size of the inner particles differs as shown in FIG.

FIG. 6 is a diagram schematically showing the degree of scattering according to the sizes of the inner particles 610, 620, and 630, and FIG. 7 is a diagram showing the difference in degree of scattering when scattering occurs at a wide angle and a narrow angle.

Referring to FIGS. 6 and 7, it can be seen that the degree of scattering increases as the particle size increases. FIG. 7A is a view showing a case where scattering is performed at a wide angle 710-1, and FIG. 7B is a view showing a case where scattering occurs at a narrow angle 720-1. FIG. It can be confirmed that the permeability (710-2, 720-2) is better in FIG. 7A than in FIG. 7B.

The total transmittance according to the wavelength of the incident light can be classified into diffuse transmittance and specular transmittance. At this time, the case where the wavelength of the diffused light diffuses at a wide angle is referred to as haze (haze), and the case where the light diffuses at a narrow angle is referred to as a clarity. Such a measurement of the transmittance is carried out using a device called a UV-vis-NIR spectrometer.

In the case of the nanofiber membrane according to an embodiment of the present invention, the nanofiber 50 may be thermally treated to improve the porosity to remove the porous structure, thereby forming a nanofiber membrane having high optical transparency.

Among various physical properties, acrylic, epoxy, cellulose, chitosin, etc. may be added to improve the mechanical properties.

In addition to using electrostatic spraying as described above, electrospinning can be performed by mixing a functional material (graphene, etc.) with the polymer solution 10. A diagram showing such a process is shown in Fig. 13 will be described later.

8 is a photograph showing electrophoresis of nanofibers using poly (ε-carprolactone) as a polymer material and immersion in ethanol and distilled water. Referring to FIG. 8, the liquid collector 60, (A) and ethanol (b) are used as the distilled water (a) and the distilled water (b), respectively.

8, when the liquid surface tension of the liquid is large in the liquid collector 60, the nanofibers 50 are repelled by the repulsive force with respect to the charges in the electrospun nanofiber 50 And accumulates on the surface of the liquid collector 60. On the other hand, when the surface tension is small, the nanofibers 50 sink under the liquid collector 60, so that the nanofibers 50 can obtain a three-dimensionally superimposed membrane.

At the surface of the liquid, the force acting on the molecule acts to shrink. This force per unit length is called surface tension. The intensity of the surface tension of the liquid is expressed by the tension acting on both sides of the line of unit length assumed on the liquid surface. The value is determined by the liquid, but also by the temperature.

For example, the surface tension is 72.75mN / m of water (810), ethanol _{(C 2 H 5 OH) (} 820) has a surface tension to reduce the contact angle with 21.78mN / m Then, the nanofibers 50 . Therefore, the three-dimensional porous nanofiber membrane according to an embodiment of the present invention uses a mixed solution of water and ethanol as the collector 60 to lower the surface tension acting between the nanofiber 50 and the nanofiber 50 Can be accumulated.

9 is a view showing the accumulation process of nanofibers according to the addition of ethanol. Referring to FIG. 9, as the ethanol is added, the surface tension is reduced, and the nanofibers 50 electrospun from PCL (polycaprolactone) are changed from the unstable state to the stable state due to the difference in surface tension. Therefore, it is confirmed that they can bond with each other and sink into the lower layer portion of the mixed solution of water and ethanol.

In FIG. 9, it can be seen that a stable three-dimensional porous nanofiber membrane can be obtained when the weight ratio of ethanol becomes 25 wt% or more. This is because, instead of hydrophilic water for nanofibers in the hydrophobic state, elements that can repel each other due to the addition of ethanol having a relatively low hydrophilicity can be reduced.

When ethanol having a low surface tension is used as described above, the nanofibers 50 can be accumulated over a certain thickness despite the (+) charged state of the nanofibers. The liquid collector 60 can be easily transferred to a desired substrate and the membrane can be obtained without impurities. It is also effective to make the membrane thicker because it is easy to stack. Therefore, as shown in FIG. 6, it can be confirmed that the nanofiber membrane is stably formed when ethanol is contained in an amount of 25 wt% or more.

10 is a graph showing the thickness of the membrane according to the electrospinning time according to Comparative Examples and Examples. Referring to the comparative example 1010 in FIG. 10, Cu (metal) is used as the collector. In the embodiment 1020, a liquid mixture of ethanol and water is used as the liquid collector 60. The membrane produced by electrospinning may have a thickness of the nanofibers deposited at a spinning time of 100 μm or more per hour.

Hereinafter, a process of carbonizing a nanofiber membrane, which is an electric insulator, will be described in detail as another embodiment.

The above-mentioned nanofiber membrane includes a polymer fiber as a main component by using an electrospinning process, so that it is difficult to fundamentally solve the problem of porosity and electrical insulation. However, if the nanofiber membrane is subjected to the above-described process at a high temperature, the polymer component may be gasified to produce a porous carbon conductive membrane having excellent mechanical and electrical properties.

In other words, nanofibers that have only passed through electrospinning have characteristics as an insulator, but when they are stabilized and carbonized, the electrical properties can be improved by high temperature treatment. The stabilization process is a process for preventing the fiber from melting at a high temperature.

The stabilization process is generally performed by preventing the electrospun nanofiber 50 from being melted at a high temperature so as to be subjected to a stabilization process at a low temperature elevating speed for a long time so as to produce carbon nanofibers excellent in physical characteristics.

In the carbonization process, when heated at 800 to 1200 ° C in an inert atmosphere, a large amount of HCN gas is generated and an increase of N ₂ gas is remarkable, resulting in generation of CH ₄ , CO ₂ , and CO, and the structure of the condensed ring in the nanofiber is increased The incomplete graphite crystal plane is formed and carbonized to obtain a high-strength carbon nanofiber.

FIGS. 11 and 12 are photographs showing an improvement in electrical characteristics when rGO is electrostatically sprayed, respectively. FIG. 11 is a photograph showing that the electrospun nanofibers are improved in electrical properties through stabilization and carbonization processes.

FIG. 11 is a photograph showing the sheet resistance lowered to 1000? / Sq when the electrospray process is performed. As shown in FIG. 4, the electrostatic spraying and the electrospinning can be carried out at the same time, which can overcome the limitation of the electrospinning, which is composed of a simple polymer material. Through such a process, the application as an active material of a supercapacitor can be expected.

12, it is possible to manufacture a porous three-dimensional membrane having a low sheet resistance composed of a carbonaceous material having high electrical conductivity after carbonization of the membrane made of nanofibers. The carbon nanofiber membrane shown in FIG. 12 is a photograph showing that carbon nanofibers having a porosity of 20? / Sq or less were produced.

As described above, it is possible to overcome the limitation of the amount that can be added when mixing electrostatic spraying with electrospinning and a substance added to a structure, which is a problem occurring in a composite structure through a carbonization process.

The nanofiber membrane manufactured by the method according to an embodiment of the present invention can be filled with a material to which a porous portion is added so that a nanocomposite structure having a very high content of additive materials can be manufactured. Accordingly, It can be said that the application is expected.

13 is a flowchart illustrating a process of manufacturing a membrane according to an embodiment of the present invention. Particularly, Fig. 13 is a process for mixing electrospun with functional materials. Referring to FIG. 13, a polymer solution is prepared by mixing a polymeric material in powder form (that is, polymer powder) and a functional material into a solvent capable of dissolving the polymer material (S1310) (S1320) spinning the nanofibers to produce nanofibers, and accumulating the nanofibers on the liquid collector to produce nanofiber membranes (S1330).

Step S1320 includes applying a voltage to a spinning nozzle for spinning the polymer solution, and radiating the polymer solution from the spinning nozzle to the liquid collector.

Here, the functional material may be at least one selected from a metal nanomaterial, a carbon nanomaterial, cellulose, acryl, epoxy, chitosan, graphene, rGO, and CNT.

The polymer that is electrospun during the manufacturing process may have a superhydrophobic property. Thus, the superhydrophobic polymer may float on the liquid collector 60 due to its repulsive force.

For example, the metal nanomaterial may be selected from the group consisting of Ag, Cu, Co, Sc, Ti, Cr, Mn, (Ni), Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, (Pd), cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Hg), lanthanide, and actinoid, silicon, germanium, tin, arsenic, antimony, bismuth, gallium, Gallium (Ga), indium (In), or the like.

In addition, the carbon and metal nanomaterials may be composed of various nano-shaped materials, and examples thereof include a nanoparticle, a nanowire, a nanotube, a nanorod, and at least one selected from the group consisting of a nanowall, a nanobelt, and a nanorring.

The polymeric material used in one embodiment of the present invention may be any material as long as it is an electrospun material. Preferably, the polymeric material is selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA) But are not limited to, polydimethylsiloxane (PDMS), polyurethane, polyether urethane, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, polymethyl acrylate (PMA), polyvinyl acetate (PVAc), polyacrylonitrile , Polypropylene oxide (PPO), polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, polyamide, Polylactide, polyglycolide, polyglycolide, polycaprolactone, plimethylene carbene carbonate, polyamino acid, polyorthoester , And polyurethane resins such as polyurethane copolymers, polyacrylic copolymers, polyvinyl acetate copolymers, polystyrene copolymers, polyethylene oxide copolymers, polypropylene oxide copolymers, polyvinylidene fluoride copolymers, polylactide copolymers, At least one selected from the group consisting of a lead copolymer, a polycaprolactone copolymer, a polytrimethylene carbene carbonate copolymer, a polyamino acid copolymer, and a polyorthoester copolymer.

The solvent used in one embodiment of the present invention may be any solvent as long as it can dissolve the polymeric material. Preferably, the solvent is a solvent such as methanol, acetone, tetrahydrofuran, toluene or dimethylformamide A polymer solution in which the polymer powder described above is dissolved. For example, the soluble solvent may be selected from the group consisting of Alkanes such as hexane, Aromatics such as toluene, ethers such as diethyl ether, chloroform, Such as alkyl halides, such as Alkyl halides, Esters, Aldehydes, Ketones, Amines, Alcohols, Amides, Carboxylic acids, Carboxylic acids, and water. In addition, for example, the above-mentioned polymer solution can be formed using the above-mentioned organic solvent. However, such a polymer solution is illustrative, and the technical idea of the present invention is not limited thereto.

Preferably, the polymer solution may comprise less than 1.5% by weight of poly (epsilon -caprolactone) based on the total weight of the polymer solution, and the poly (epsilon -caprolactone) is selected from the group consisting of methylene chloride, dimethyl chloride and dimethylformamide Lt; / RTI > by volume of the solvent mixture.

When a polymer droplet or the nanofiber is electrostatically sprayed or electrospinned from such a polymer solution, an electrostatic force capable of forming a nanofiber membrane can be obtained by positively charging the nanofiber.

Electrospinning is a technique for producing microfine fibers with a diameter of tens to hundreds of nanometers. It is believed that electrospinning is the most advantageous for industrialization because it is easier to apply and easier to apply than other nanofiber manufacturing methods.

FIG. 14 is a flowchart showing a manufacturing process of a membrane according to another embodiment of the present invention. Particularly, Fig. 14 is a process for manufacturing a nanofiber membrane using electrospinning and electrostatic spraying. Referring to FIG. 14, there is provided a method of manufacturing a polymer electrolyte fuel cell, comprising the steps of (S1410) preparing a polymer solution by dissolving a polymer powder in a solvent, preparing a mixed solution containing a functional material (S1420) Forming a fiber web and simultaneously forming a spray of the mixed solution by applying a voltage lower than the high voltage to the functional material at step S1430; inserting the functional material into the nanofibers to form nanofibers at step S1440 And collecting the nanofibers from the liquid collector to produce a porous nanofiber membrane (S1450).

In particular, the nanofiber membrane according to another embodiment of the present invention includes a graphene powder including nanofibers electrospun from a polymer material and electrostatically sprayed at the same time during the electrospinning, The powder may be filled in the inside of the electrospun nanofiber and have a thickness of 300 mu m or more.

In addition, after step S1450, stabilization of the porous nanofiber membrane may be further performed by heating the porous nanofiber membrane in an inert atmosphere at 800-1200 DEG C to carbonize the porous nanofiber membrane.

The graphene 70 may include at least one selected from a metal nanomaterial, a carbon nanomaterial, cellulose, acrylic, epoxy, chitosan, rGO, and CNT.

While the present invention has been described with reference to the accompanying drawings, it is to be understood that the present invention is not limited to any of the various embodiments including the gist of the present invention, It is clear that the present invention is not limited to the above-described embodiments. Accordingly, the scope of protection of the present invention should be construed according to the following claims, and all technical ideas which fall within the scope of equivalence by alteration, substitution, substitution, Range. Also, it should be clarified that some of the drawings are intended to illustrate the structure more clearly and are provided in an exaggerated or reduced size than the actual one.

10: polymer solution 20: syringe pump
30: Spinning nozzle 40: Taylor cone
45: liquid crystal solution 50: nanofiber
60: collector 70: graphene

Claims

A method for manufacturing a three-dimensional nanofiber membrane using electrospinning,
(a) preparing a polymer solution by mixing a powdery polymer material and a functional material into a solvent capable of dissolving the polymer material;
(b) electrospinning the polymer solution to produce nanofibers; And
(c) accumulating the nanofibers on a liquid collector to produce a three-dimensional nanofiber membrane,
Wherein the functional material is at least one selected from the group consisting of a metal nanomaterial, a carbon nanomaterial, cellulose, acrylic, epoxy, chitosan, graphene, reduced graphene oxide (rGO), and carbon nanotube (CNT)
Wherein the nanofibers are coated on the surface of the functional material.

A method for manufacturing a three-dimensional nanofiber membrane using electrospinning and electrostatic spraying,
(a) preparing a polymer solution by dissolving the polymer material in a solvent;
(b) preparing a mixed solution containing a functional material;
(c) forming a nanofiber web by electrospinning the polymer solution by applying a high voltage to the polymer solution, and forming a spray of the mixed solution by electrostatic atomization by applying a voltage lower than the high voltage to the functional material;
(d) inserting the functional material into the nanofibers to form nanofibers; And
(e) collecting the nanofibers in a liquid collector to produce a porous three-dimensional nanofiber membrane,
Wherein the nanofibers are coated on the surface of the functional material.

3. The method according to claim 1 or 2,
Wherein the liquid collector comprises water and ethanol,
Wherein the thickness of the nanofibers to be deposited according to the spinning time is 100 m or more per hour.

3. The method according to claim 1 or 2,
The solvent may be selected from the group consisting of Alkanes containing hexane, Aromatics containing toluene, Ethers containing diethyl ether, alkyl halides including chloroform, Alkyl halides, Esters, Aldehydes, Ketones, Amines, Alcohols, Amides, Carboxylic acids, Carboxylic acids, And water. 2. The method according to claim 1,

3. The method according to claim 1 or 2,
The polymeric material may be selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyurethane, polyether urethane, cellulose acetate, cellulose acetate butyrate , Cellulose acetate propionate, polymethyl acrylate (PMA), polyvinyl acetate (PVAc), polyacrylonitrile (PAN), polyperfuryl alcohol (PPFA), polystyrene, polyethylene oxide (PEO), polypropylene oxide PPO), polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, polyamide, polylactide, polyglycolide, polyglycolide, polycaprolactone, , Polyamino acids, polyorthoesters, polyurethane copolymers, polyacrylic copolymers, polyvinylacetate copolymers, polystyrene balls A polymer, a polyethylene oxide copolymer, a polypropylene oxide copolymer, a polyvinylidene fluoride copolymer, a polylactide copolymer, a polyglycolide copolymer, a polycaprolactone copolymer, a polytrimethylene carbene carbonate copolymer, a poly Amino acid copolymers, and polyorthoester copolymers. The method for producing a three-dimensional nanofiber membrane according to claim 1,

The method according to claim 1,
The step (b)
(b-1) applying a voltage to a spinneret for spinning the polymer solution; And
(b-2) radiating the polymer solution from the spinning nozzle to the liquid collector.

3. The method of claim 2,
The functional material may be,
Wherein the metal nanoparticle comprises at least one selected from the group consisting of metal nanomaterials, carbon nanomaterials, cellulose, acryl, epoxy, chitosan, rGO, CNT, metal nanowires, and metal nanoparticles.

8. The method of claim 7,
Wherein the rGO (reduced graphene oxide) has a sheet resistance of 1000 OMEGA / sq or less.

8. The method of claim 1 or 7,
The metal nanomaterial may be at least one selected from the group consisting of Ag, Cu, Co, Sc, Ti, Cr, Mn, (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technenium (Tc), ruthenium (Ru) ), Cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum ), Lanthanide, actinoid, silicon, germanium, tin, arsenic, antimony, bismuth, gallium, , And indium (In). The method of manufacturing a three-dimensional nanofiber membrane according to claim 1,

3. The method of claim 2,
(f) stabilizing the porous three-dimensional nanofiber membrane; And
(g) carbonizing the porous nanofiber membrane by heating at 800 to 1200 占 폚 in an inert atmosphere.

11. The method of claim 10,
Wherein the porous three-dimensional nanofiber membrane has a sheet resistance of 20? / Sq or less.

3. The method of claim 2,
Wherein the electrospinning is coaxial electrospinning, and the nanofiber is coated with nanofibers of polymer fibers on the surface of the functional material.

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