KR102139711B1 - Nanofibrous Membrane and Method for Preparing Thereof - Google Patents

Abstract

The present invention is a support; A first polymer nanofiber layer formed on the support by electrospinning and having a surface plasma-treated; And a second polymer nanofiber layer formed by electrospinning on the first polymer nanofiber layer and coated with a conductive polymer on the surface; electrospinning the first polymer solution onto the nanofiber membrane and the support, thereby including the first polymer nano Forming a fiber layer; Plasma treating the surface of the first polymer nanofiber layer; Forming a second polymer nanofiber layer by electrospinning a second polymer solution on the plasma-treated first polymer nanofiber layer; And polymerizing a conductive polymer monomer on the second polymer nanofiber layer by vapor deposition to form a conductive polymer layer.

Description

Nanofibrous membrane and its manufacturing method {Nanofibrous Membrane and Method for Preparing Thereof}

The present invention relates to a nanofiber membrane and a method for manufacturing the same.

It is well known that fine dust has a very harmful effect on the human body to the extent that it is designated as a first-class carcinogen by the World Health Organization (WHO). Particularly, in recent years, the frequency of occurrence of fine dust has increased and the damage has been seriously increased due to the development of the industry and the increased use of fossil fuels. In general, the fine dust refers to a particulate matter having a diameter of 10 μm or less, and is classified into fine dust (PM (Particulate meter) 10), fine dust (PM2.5), and ultra fine dust (PM1). That is, the fine dust (PM10), the ultrafine dust (PM2.5), and the ultrafine dust (PM1) mean the degree of contamination by measuring the mass concentration of particulate matter having a particle diameter of approximately 10 μm, 2.5 μm, 1 μm or more, respectively. do.

When exposed to such fine dust, it can cause various diseases such as respiratory diseases, skin diseases, and acute allergies. Accordingly, interest in mask filters for preventing external air contaminated such as fine dust or yellow dust from entering the human body, ventilation systems capable of purifying contaminated air in the room, and air purification filters is increasing.

In order to block such fine dust, various studies have been conducted, such as using a nonwoven fabric such as a polymer microfiber membrane produced by a melt blown method on a dust-proof mesh, but a filter for blocking fine dust by a melt-blown method It is difficult to block ultra fine dust below PM2.5.

To overcome this, filters using nanofibers capable of trapping and filtering ultra-fine particles have been developed. When applied over a mesh, the nanofibers do not adhere to the mesh and thus cannot retain the filter function. There is no problem, and because the physical strength is very low, it is easily damaged by external impact or friction, and may cause the product to deteriorate.

Accordingly, research is being conducted to increase the efficiency of collecting fine dust compared to a differential pressure while having excellent durability.

Korea Patent Publication No. 2016-0071761

The object of the present invention is to show excellent performance in the collection of fine dust of various sizes ranging from ultrafine dust (PM1), while functionalizing the surface of the nanofiber layer using heterogeneous functional nanofibers, at the same time introducing a conductive polymer It is to provide a nanofiber membrane for collecting high-efficiency fine dust and a filter using the same, because conductivity is imparted.

In addition, the functional nanofibers as described above have excellent adhesion to each other and are excellent in durability, while optimizing the thickness of the nanofiber layer to provide a nanofiber membrane having excellent dust collection efficiency against differential pressure and a filter using the same.

In order to achieve the above object, the present invention is a support; A first polymer nanofiber layer formed on the support by electrospinning and having a surface plasma-treated; And a second polymer nanofiber layer formed by electrospinning on the first polymer nanofiber layer and coated with a conductive polymer on the surface.

In addition, the present invention is a step of forming a first polymer nanofiber layer by electrospinning the first polymer solution on a support; Plasma treating the surface of the first polymer nanofiber layer; Forming a second polymer nanofiber layer by electrospinning a second polymer solution on the plasma-treated first polymer nanofiber layer; And polymerizing a conductive polymer monomer on the second polymer nanofiber layer by vapor deposition to form a conductive polymer layer.

The nanofiber membrane of the present invention functionalizes the surface by forming a double nanofiber layer using heterogeneous functional nanofibers, and at the same time, conductivity is imparted by introducing a conductive polymer, so that fine dust can be collected with very high efficiency. In addition, as the surface of the nanofiber layer is plasma-treated, the adhesion between the heterogeneous nanofiber membranes is increased to increase the durability of the filter, while optimizing the thickness of the nanofiber layer and the conductive polymer layer, and the dust collection efficiency of fine dust compared to the differential pressure is remarkably excellent. have.

Furthermore, it is eco-friendly by using biodegradable resins such as PAN, PVA, and PEO, and is excellent in biocompatibility even when used as a mask filter that directly contacts the human body, and additional auxiliary equipment (ionization for improving the dust collection efficiency of nanofiber membranes) Since it can be manufactured by a simple electrospinning method without requiring equipment, etc., there is an effect of improving productivity and reducing manufacturing cost.

1 is a view showing a cross-section of a nanofiber membrane structure formed of a PVA nanofiber layer coated with a support/plasma-treated PAN nanofiber layer/conductive polymer according to an embodiment of the present invention.
2 is a view showing a support/plasma surface treated PAN nanofiber layer according to an embodiment of the present invention.
3 is a view showing a dual nanofiber layer obtained by electrospinning PVA on a support/plasma surface treated PAN nanofiber layer according to one embodiment of the present invention for 15 minutes.
4 is a view showing a dual nanofiber layer obtained by electrospinning PVA on the support/plasma surface treated PAN nanofiber layer according to one embodiment of the present invention for 30 minutes.
5 is a view showing a vapor deposition process for forming a conductive polymer layer on a support/plasma-treated PAN nanofiber layer/PVA nanofiber layer according to an embodiment of the present invention.
6 is a view showing a nanofiber film formed of a PVA nanofiber layer coated with a support/plasma-treated PAN nanofiber layer/conductive polymer according to an embodiment of the present invention.
7 is a view showing a micrograph of a nanofiber film formed of a PVA nanofiber layer coated with a support/plasma-treated PAN nanofiber layer/conductive polymer according to an embodiment of the present invention.
8 is an SEM photograph showing the surface of a nanofiber film formed of a support/plasma-treated PAN nanofiber layer/PVA nanofiber layer coated with a conductive polymer according to an embodiment of the present invention.
9 is an SEM photograph showing the surface of a nanofiber film formed of a support/plasma-treated PAN nanofiber layer/PVA nanofiber layer coated with a conductive polymer according to an embodiment of the present invention.
10 is a SEM photograph showing the surface of a nanofiber film formed of a support/plasma-treated PAN nanofiber layer/PVA nanofiber layer coated with a conductive polymer according to an embodiment of the present invention.
11 is a view showing an experiment for measuring the surface resistance of a nanofiber film formed of a PVA nanofiber layer coated with a support/plasma-treated PAN nanofiber layer/conductive polymer according to an embodiment of the present invention.
12 is a schematic view showing a process for removing fine dust from a nanofiber film formed of a support/plasma treated PAN nanofiber layer/PVA nanofiber layer coated with a conductive polymer according to an embodiment of the present invention.
13 is an SEM photograph showing the surface of a nanofiber membrane after collecting fine dust using a nanofiber membrane formed of a support/plasma-treated PAN nanofiber layer/PVA nanofiber layer coated with a conductive polymer according to an embodiment of the present invention .
14 is a micrograph of a nanofiber membrane formed of a PVA nanofiber layer/conductive polymer layer without a first polymer nanofiber membrane according to Comparative Example 1 of the present invention.
15 is an enlarged plan view of a nanofiber membrane structure formed of a first polymer nanofiber layer coated with a support/plasma-treated first polymer nanofiber layer/conductive polymer according to an embodiment of the present invention.
16 is a cross-sectional view of a second polymer nanofiber strand coated with a conductive polymer on a surface according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention is a support; A first polymer nanofiber layer formed on the support by electrospinning and having a surface plasma-treated; And a second polymer nanofiber layer formed by electrospinning on the first polymer nanofiber layer and coated with a conductive polymer on the surface.

Hereinafter, each configuration of the nanofiber membrane of the present invention will be described in detail.

The support may be a non-woven fabric, a mesh material, etc., and is not limited to this as long as it is a porous substrate.

The material of the non-woven fabric and mesh material is polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride, nylon (nylon), or Cellulose, and the like.

The thickness of the nonwoven fabric may be 0.1 mm to 5.0 mm, and the thickness of the mesh material may be 0.1 mm to 1.0 mm.

The first polymer nanofiber layer is a polymer nanofiber of 1 to 500 ㎚ having a porous structure, such as a non-woven fabric form, because it has a microscopic size of the diameter, has a larger surface area than the conventional fiber and has a nano-sized pore, thereby collecting Efficiency can be increased.

The first polymer nanofiber layer may be formed by electrospinning a first polymer solution containing a first polymer resin on the support, and the diameter of the first polymer nanofiber formed as above is at a polymer concentration, viscosity, and nozzle. It can be done differently by adjusting the distance to the collector (fiber collecting plate), the applied voltage, the supply speed of the polymer solution, and the spinning environment. Specifically, when the polymer concentration and viscosity of the nanofibers are increased, the distance between the nozzle and the collector is increased, or the applied voltage is decreased, the diameter of the nanofibers becomes large. Conversely, when the polymer concentration and viscosity are lowered, the distance between the nozzle and the collector is increased, or the applied voltage is increased, the diameter of the nanofibers becomes small.

The first polymer resin may be electrospinned to form fibers, that is, any spinning polymer resin may be used without limitation, for example, polycaprolactone (poly(e-caprolactone); PCL], polylactic acid [(poly)lactic acid; PLA], polyglycolic acid [(poly)glycolic acid; PGA], polyhydroxy valerate [poly(hydroxy valerate); PHV], poly(lactic-co-glycolic acid); PLGA], polyhydroxybutyrate (PHB), polyhydroxybutylate cobalerate [poly(hydroxy butyrate-co-valerate); PHBV], polyanhydride, polyorthoester, poly(vinyl alchol); PVA], polyethylene oxide (PEO), polyurethane (polyurethane), polyacrylic acid (PAA), poly-N-isopropylacrylamide [poly(N-isopropylacrylamide)], diol/diacid aliphatic Polyester, polyester-amide/polyester-urethane, polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride ( polyvinylidene fluoride), nylon, polyvinyl acetate [Poly(vinyl acetate); PVAc], polymethyl methacrylate [Poly(methyl methacrylate); PMMA], polyacrylonitrile (PAN), polybutylene terephthalate (poly(butyleneterephthalate); PBT], Poly vinyl butyral, Poly vinyl chloride (PVC), Polyethyleneimine (PEI), Polyolefin, Polyethylene naphthalate (PEN), Polyamide ( Polyamide; PA), silk, cellulose, chitosan, and the like.

The first polymer resin is preferably a polyacrylonitrile (PAN) having a large dipole moment.

The weight average molecular weight (g/mol) of the first polymer resin may be 5,000 to 200,000. When the weight average molecular weight of the first polymer resin is less than 5,000, it does not have a sufficient viscosity with a low molecular weight, and thus, when electrospinning, it does not form a fiber form in a spray form rather than a spinning form, and does not form a fiber, and the weight average molecular weight In the case of more than 200,000, it has a high viscosity and solidifies on the surface of the solution when spinning, so that spinning for a long time is impossible.

At this time, the first polymer nanofiber layer is further added to an adhesive material such as an adhesive protein, an adhesive polysaccharide, an adhesive polymer to simultaneously improve dust collection efficiency for polar substances such as fine dust and collection efficiency for non-polar substances such as bio-floats. It can contain.

The thickness of the first polymer nanofiber layer may be 100 to 900 μm. When the thickness of the first polymer nanofiber layer is less than 100 μm, there is a problem that fine dust cannot be collected and escapes, and when it is more than 900 μm, a differential pressure is generated and air circulation (air flow) may occur. .

In addition, the surface of the first polymer nanofiber layer may be plasma treated.

The surface of the plasma-treated first polymer nanofiber layer introduces a functional group on the surface of the nanofiber by plasma generated by discharge to increase the physical and chemical bonding force between the fine dust and the nanofiber, thereby improving the capture power. In addition, by reducing the diameter of the nanofibers, it is possible to increase the specific surface area to improve the performance and extend the life of the nanofiber membranes or filters, minimize the pressure loss of air, reduce the required power, and the thickness of the manufactured nanofiber membranes. It is possible to manufacture a thin nanofiber film by reducing.

Specifically, an amide group (-CONH), an ester group (-COOR), and a carboxyl group (-COOH) are applied to the nanofiber by surface treatment with reactive gas (reactive ions) in the state where oxygen gas is injected, that is, surface treatment of reactive ion etching. It can be formed, it is possible to control the amount of functional groups and the degree of etching the nanofibers by controlling the time of surface treatment, the amount of injection gas, and the pressure of the chamber.

In addition, the surface of the plasma-treated first polymer nanofiber layer may chemically and physically improve the wettability of the surface by plasma generated by discharge to lower the contact angle, which means that the surface energy increases. . As a result, as the surface energy of the first polymer nanofiber layer increases, adhesion to other substrates such as the second polymer nanofiber layer may increase.

As shown in FIG. 14, when only the nanofibers coated with the conductive polymer are used, there is a problem that a hole (the portion where the nanofibers are not coated) occurs during vapor deposition polymerization, so that only the nanofibers coated with the conductive polymer are singly. It cannot be used. To compensate for this, an optimized functional nanofiber (first polymer nanofiber layer) was formed between the support and the conductive polymer coated nanofiber layer (second polymer nanofiber layer).

As described above, the method of manufacturing a nanofiber membrane for collecting fine dust using heterogeneous functional polymer nanofibers according to the present invention is when manufacturing only a nanofiber coated with a conductive polymer capable of effectively collecting fine dust as a nanofiber membrane By overcoming the problems that arise, and utilizing the advantages of each of the heterogeneous functional polymer nanofibers, it is possible to manufacture nanofiber membranes and filters for collecting high-efficiency fine dust. In addition, by using an electrospinning method, it is possible to minimize separation or damage of nanofibers in a vapor deposition polymerization process by electrostatic attraction generated during electrospinning.

The second polymer nanofiber layer, like the first polymer nanofiber layer, has 1 to 500 nm of polymer nanofibers having a porous structure such as a non-woven fabric, and having nano-sized pores, so that even ultrafine dust of PM1 is efficient. Serves as a collector.

The second polymer nanofiber layer may be formed by electrospinning a second polymer solution containing a second polymer resin on the first polymer nanofiber layer.

The second polymer resin is polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), poly Vinyl acetate (PVAc), polymethyl methacrylate (PMMA), polyurethane, polyvinyl butyral (PVB), polyvinyl chloride (PVC), polyethylene bi(PEI), polyethylene naphthalate (PEN), polyamide (PA ), polyethyleneimide, polycaprolactone (PCL), cellulose, polyimide (PI), polysulfone, or polyether ketone, and may be poly in terms of adhesion, adhesion, or dust collection efficiency with the first polymer nanofiber layer. Vinyl alcohol or polyvinylidene fluoride is preferred.

The weight average molecular weight (g/mol) of the second polymer resin may be 20,000 to 100,000. When the weight average molecular weight of the second polymer resin is less than 20,000, it does not have a sufficient viscosity with a low molecular weight, and thus, when electrospinning, it does not form a fiber rather than a spinning type and does not form a fiber, and the weight average molecular weight In the case of more than 100,000, it has a high viscosity and solidifies on the surface of the solution during spinning, so that spinning for a long time is impossible.

In this case, the second polymer nanofiber layer is further added with an adhesive material such as an adhesive protein, an adhesive polysaccharide, and an adhesive polymer to simultaneously improve dust collection efficiency for polar materials such as fine dust and collection efficiency for non-polar materials such as bio-floats. It can contain.

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The conductive polymer layer may be a film containing at least one selected from the group consisting of polypyrrole, polythiophene, polyaniline, polyphenylene sulfide, polyphenylenevinylene, polyfuran, polysulfurnitride, and polyethylenedioxythiophene. , In view of maximizing the collection efficiency of fine dust compared to the differential pressure, polyethylene dioxythiophene is preferred.

16 shows a second polymer nanofiber coated with a conductive polymer. The conductive polymer layer is formed on the surface of the second polymer nanofiber with a thickness of 5 to 50 nm. When the thickness of the conductive polymer layer is less than 5 nm, there is a problem that the conductive polymer is not uniformly formed on the surface of the second polymer nanofiber, so that a smooth current does not flow, and when it is more than 50 nm, the fiber thickness is thickened and the differential pressure increases. There is a problem that the shape occurs.

The collection efficiency of fine dust of the nanofiber membrane may be 80 to 99.9%.

In addition, the present invention is a step of forming a first polymer nanofiber layer by electrospinning the first polymer solution on a support; Plasma treating the surface of the first polymer nanofiber layer; Forming a second polymer nanofiber layer by electrospinning a second polymer solution on the plasma-treated first polymer nanofiber layer; And polymerizing a conductive polymer monomer on the second polymer nanofiber layer by vapor deposition to form a conductive polymer layer.

Hereinafter, each step of the method for manufacturing a nanofiber membrane of the present invention will be described in detail.

The first polymer nanofiber layer may be formed by electrospinning the first polymer solution on the support.

The electrospinning is a method of manufacturing a yarn-like fiber having a nano-scale diameter through a jet of the first polymer solution dissolved in an electric field, that is, the first electrically charged polymer solution. .

Electrospinning largely consists of the steps of jet formation, stretching and solidification. Specifically, one jet is formed from the polymer solution by the nozzle. Before the voltage is applied, the polymer solution is suspended in the form of a spherical drop due to the surface tension at the tip of the nozzle, and then a voltage (external electric field) is applied, and electric charge is introduced to the surface of the drop, sprayed from the tip of the drop I go out and this is called a taylor cone. The hemispherical surface of the polymer solution is stretched into a conical shape known as a Taylor cone, and at a specific electric field strength (Vc), the repulsive electrostatic force overcomes the surface tension, so that a jet of charged polymer solution is released from the end of the Taylor cone. Subsequently, as the axial velocity of the Taylor cone accelerates, the jet shrinks in diameter and lengthens. The jet is driven by the electrical potential difference supplied between the polymer solution and the current collector. This stretching occurs because the emissive force of the electrical charge due to the tapered and elongated jet is greater than the adhesive force in the jet. At this time, the jet is a somewhat complicated process in which the object is split or separated into several objects. In order to solve this, the jet which is unstable due to the electric charge accumulated locally on the jet surface causes small jets to be released from the jet surface. Separate or split. This phenomenon occurs mainly in high-concentration and high-viscosity polymer solutions. Due to the instability of the above jet, it plays an important role in reducing the diameter of the finally obtained nanofiber from micro size to nano scale. Finally, when the jet stretched on the current collector plate is dried and solidified, nanofibers are finally formed.

The applied voltage of the electrospinning may be 10 to 25 kV, and the flow rate may be 0.1 to 1.5 ml/h. When the applied voltage is less than 10 kV, there is a problem of spraying in a particle form, not a fiber form, and when it is more than 25 kV, there may be a safety problem. In addition, when the flow rate is less than 0.1 ml/h, there is a problem that the spinning takes too long because the speed is too slow, and when it exceeds 1.5 ml/h, there is a problem that the loss of the spinning solution (polymer solution) increases during spinning. .

In addition, the distance between the syringe needle and the spun fiber collection plate (support or the first polymer nanofiber layer) during the electrospinning is preferably adjusted to 7 to 25 cm, and the distance between the syringe needle and the spun fiber collection plate is 7 If it is less than cm, the nanofibers are spun to a very narrow area, and the entire spun fiber may not be uniform. If it is more than 25 cm, the voltage is not applied to both the syringe needle and the spun fiber collecting plate, so that the spinning is not properly performed. It may not.

Very fine nanofibers can be produced according to the electrospinning as described above, and the first polymer nanofiber layer and the second polymer nanofiber layer formed as described above have a dense nano-sized porous structure, ultimately causing fine dust. It improves the collection efficiency and does not require a separate device, such as an ionization device, to improve the dust collection efficiency of the nanofiber membrane, so it is simple to manufacture, thereby improving productivity and reducing manufacturing cost.

The first polymer solution may be a spinning solution prepared by dissolving a first polymer resin and a first solvent.

The first polymer resin may include poly(e-caprolactone); PCL], polylactic acid [(poly)lactic acid; PLA], polyglycolic acid [(poly)glycolic acid; PGA], polyhydroxy valerate [poly(hydroxy valerate); PHV], poly(lactic-co-glycolic acid); PLGA], polyhydroxybutyrate (PHB), polyhydroxybutylate cobalerate [poly(hydroxy butyrate-co-valerate); PHBV], polyanhydride, polyorthoester, poly(vinyl alchol); PVA], polyethylene oxide (PEO), polyurethane (polyurethane), polyacrylic acid (PAA), poly-N-isopropylacrylamide [poly(N-isopropylacrylamide)], diol/diacid aliphatic Polyester, polyester-amide/polyester-urethane, polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride ( polyvinylidene fluoride), nylon, polyvinyl acetate [Poly(vinyl acetate); PVAc], polymethyl methacrylate [Poly(methyl methacrylate); PMMA], polyacrylonitrile (PAN), polybutylene terephthalate (poly(butyleneterephthalate); PBT], Poly vinyl butyral, Poly vinyl chloride (PVC), Polyethyleneimine (PEI), Polyolefin, Polyethylene naphthalate (PEN), Polyamide ( Polyamide; PA), silk, cellulose, or chitosan.

The first polymer resin is preferably a polyacrylonitrile (PAN) having a large dipole moment.

The first solvent is formic acid, sulfuric acid, difluoroacetanehydride/dichloromethane, water (distilled water), N-methylmorpholine N-oxide, chloroform, tetrahydrofuran, methylisobutylketone, methylethylketone, n -Butyl alcohol, isobutyl alcohol, isopropyl alcohol, methyl alcohol, ethanol, acetic acid-2-ethoxyethanol, 2-ethoxyethanol, hexane, tetrachloroethylene, acetone, propylene glycol, diethylene glycol, ethylene glycol, triclo Roethylene, dichloromethane, phenol, toluene, xylene, m-cresol, cyclohexanone, cyclohexane, n-butyl acetate, ethyl acetate, butylcellosolve, dimethylformamide, dimethylacetamide, or mixtures thereof You can do it every day.

The first solvent is preferably a single component solvent, for example, dimethylformamide (DMF).

In addition, the first solvent may be a two-component solvent. When using a two-component solvent, it is preferable to use a two-component solvent in which a solvent having a high boiling point (BP) and a low solvent are mixed. If only a solvent with a high boiling point is used, spinning is not achieved, but it is sprayed, so even if particles are formed rather than fibers or spinning, beads are formed and volatilization of the solvent occurs. This is not done well, and partially melts during the lamination process of the web, resulting in clogging of pores. In addition, when only a solvent having a low boiling point is used, since the volatilization of the solvent occurs very quickly, a lot of fine fibers are generated in the needle of the spinning nozzle, which acts as a cause of spinning trouble.

The first polymer resin preferably has a content of 2 to 25 wt% based on the total weight of the first polymer solution. When the content of the first polymer resin is less than 2 wt%, it is difficult to form on the fiber due to the low viscosity of the first polymer solution, and spinning is not achieved and is spun and is spinning in the form of beads rather than fibers. Accordingly, even if spinning is performed, droplets are formed on the fiber, and thus the diameter of the fiber increases, and thus there is a problem that the dust collection efficiency may decrease. When the content of the first polymer resin is more than 25 wt%, the viscosity of the first polymer solution becomes too high and solidification occurs on the surface of the solution, so that the spinning is not smooth and thus the production of the nanofiber membrane may be difficult.

The temperature at which the first polymer resin is dissolved in the first solvent may be at room temperature (20°C) to 100°C, and specifically, at a temperature of 40°C to 90°C. When the temperature at which the first polymer resin is dissolved in the first solvent is less than room temperature, the first polymer resin may not be dissolved in the first solvent, and when it is greater than 100° C., intrinsic properties of the first polymer resin may be denatured. Can.

Subsequently, the surface of the first polymer nanofiber may be plasma treated. That is, the surface of the first polymer nanofiber layer may be plasma treated.

The plasma is an ion gas ionized gas containing ions, electrons, radicals, excitation molecules, or atoms, and is generated by electric discharge, electromagnetic vibration, shock wave, high energy radiation, and the like.

The plasma treatment is for modifying the surface of the first polymer nanofiber, and the reactive gas chemically and physically modifies the nanofiber surface by plasma generated by discharge to improve the wettability of the surface, thereby lowering the contact angle. As the energy increases, the contact force can be improved.

The plasma treatment may control the degree of surface modification according to the type and flow rate of the reactive gas, output, pressure, process time, number of cycles, and the like.

In one embodiment of the present invention, a mixed gas of O ₂ , N ₂ , NH ₃ , or CH ₃ and Ar may be injected as a reactive gas suitable for a surface modification effect through plasma, and in the present invention, O ₂ It is most preferable to use a mixed gas of and Ar, but is not limited thereto.

The degree of surface modification may be adjusted according to the type of the reactive gas and the absolute injection flow rate, as well as, for example, a ratio of oxygen to argon injection.

In the plasma treatment, a reactive gas may be injected at a rate of 10 to 100 sccm per minute, an internal pressure of 0.1 to 1 torr, a discharge power of 40 to 150 W, and a treatment time of 1 to 30 minutes, the first polymer nanofiber The surface of the plasma can be treated.

The second polymer nanofiber layer may be formed by electrospinning a second polymer solution on the plasma-treated first polymer nanofiber layer. The above-described electric radiation may be applied in the same manner.

The second polymer solution may be a spinning solution prepared by dissolving a second polymer resin and a second solvent.

The second polymer resin is polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), poly Vinyl acetate (PVAc), polymethyl methacrylate (PMMA), polyurethane, polyvinyl butyral (PVB), polyvinyl chloride (PVC), polyethylene bi(PEI), polyethylene naphthalate (PEN), polyamide (PA ), polyethyleneimide, polycaprolactone (PCL), cellulose, polyimide (PI), polysulfone, and polyether ketone may include at least one selected from the group consisting of, adhesion to the first polymer nanofiber layer In terms of adhesion or dust collection efficiency, polyvinyl alcohol or polyvinylidene fluoride is preferred.

The second solvent is formic acid, sulfuric acid, difluoroacetanehydride/dichloromethane, water (distilled water), N-methylmorpholine N-oxide, chloroform, tetrahydrofuran, methylisobutylketone, methylethylketone, n -Butyl alcohol, isobutyl alcohol, isopropyl alcohol, methyl alcohol, ethanol, acetic acid-2-ethoxyethanol, 2-ethoxyethanol, hexane, tetrachloroethylene, acetone, propylene glycol, diethylene glycol, ethylene glycol, triclo Roethylene, dichloromethane, phenol, toluene, xylene, m-cresol, cyclohexanone, cyclohexane, n-butyl acetate, ethyl acetate, butylcellosolve, dimethylformamide, dimethylacetamide, or mixtures thereof It may be a solvent.

The second solvent may be a single-component solvent, but it is also possible to use a two-component solvent, and if a two-component solvent is used, a solvent having a high boiling point (BP) and a low solvent are mixed. It is preferable to use a two-component solvent. If only a solvent with a high boiling point is used, spinning is difficult to achieve and particles are formed instead of fibers due to spraying, and beads are formed even if spinning is performed. Since the solvent does not volatilize well, it is partially melted during the lamination process of the web, resulting in clogging of pores. In addition, when only a solvent having a low boiling point is used, since the volatilization of the solvent occurs very quickly, a lot of fine fibers are generated in the needle of the spinning nozzle, which acts as a cause of spinning trouble.

The second polymer resin preferably has a content of 2 to 25 wt% based on the total weight of the second polymer solution. When the content of the second polymer resin is less than 2 wt%, it is difficult to form on the fiber due to the low viscosity of the second polymer solution, and spinning is not achieved and is spun and is spinning in the form of beads rather than fibers. Accordingly, even if spinning is performed, droplets are formed on the fiber, and thus the diameter of the fiber increases, and thus there is a problem that the dust collection efficiency may decrease. When the content of the second polymer resin is more than 25 wt%, the viscosity of the second polymer solution becomes too high and solidification occurs on the surface of the solution, so that the spinning is not smooth and thus the production of the nanofiber membrane may be difficult.

The temperature at which the second polymer resin is dissolved in the second solvent may be room temperature (20°C) to 100°C, and specifically, 40°C to 90°C. When the temperature for dissolving the second polymer resin in the second solvent is less than room temperature, the second polymer resin may not be dissolved in the second solvent, and when it is greater than 100°C, the intrinsic properties of the second polymer resin may be modified. Can.

The second polymer solution may further include an initiator that is a cationic oxidizing agent. The initiator serves to initiate polymerization such that a conductive polymer monomer is polymerized by vapor deposition on the surface of the second polymer nanofiber so that the conductive polymer is coated on the second polymer nanofiber layer.

The initiator is Fe(NO ₃ ) ₃ , Fe(SO ₄ ) ₃ , Fe(ClO ₄ ) ₃ , Fe(NO ₂ ) _2, Ni(NO ₃ ) ₂ , Pd(NO ₃ ) ₂ , Mg(NO ₃ ) ₂ , FeCl ₃ , NiCl ₂ , CuCl ₂ , MgC _l2 , PdCl ₂ , CoCl ₂ , TiCl ₄ , TaCl ₂ , MnCl ₂ , Na(CH ₃ COOH), Ca(CH ₃ COOH), or mixtures thereof can be used have.

The initiator may be included in an amount of 1 to 15 wt% based on the total weight of the second polymer solution, and specifically, may be included in an amount of 3 to 10 wt%. When the content of the initiator is less than 1 wt%, the conductive polymer monomer is not sufficiently oxidized, and thus a polymerization reaction is impossible. When the content of the initiator is more than 15 wt%, the electrospinning of the second polymer solution is not smooth. It is impossible to manufacture nanofibers.

The first polymer solution or the second polymer solution is an adhesive material such as an adhesive protein, an adhesive polysaccharide, and an adhesive polymer in order to simultaneously improve dust collection efficiency for polar substances such as fine dust and collection efficiency for non-polar substances such as bio-floats. It may further include. The adhesive material may be specifically mucin, mucoid, gelatin, chitin, chitosan, amylopectin, and the like.

The adhesive material may be included in the first polymer solution or the second polymer solution in an amount of 0.01 to 15 wt% based on the total weight of each solution, specifically, in an amount of 0.01 to 10 wt% . When the content of the adhesive material is less than 0.01 wt%, the proportion of the adhesive material is relatively small, so that the adhesive force of the spun nanofiber film may be lowered, and when the content of the adhesive material exceeds 15 wt%, dispersion of the polymer solution The workability may be poor when the nanofiber membrane is manufactured through electrospinning because it is not perfectly made.

Next, the conductive polymer monomer may be polymerized on the second polymer nanofiber layer through vapor deposition to form or coat the conductive polymer layer.

The vapor deposition includes physical vapor deposition and chemical vapor deposition, but may be used without limitation as long as it can polymerize the conductive polymer monomer to the second polymer nanofiber layer.

The conductive polymer monomer may be used regardless of its kind as long as it is polymerized by a cationic initiator. Specifically, at least one selected from the group consisting of pyrrole, thiophene, aniline, p-phenylene sulfide, p-phenylene vinylene, furan, sulfonytrid and 3,4-ethylenedioxythiophene (EDOT) When considering the dust collecting performance of fine dust, 3,4-ethylenedioxythiophene (EDOT) having excellent conductivity is preferable.

The vapor deposition may use a commonly used evaporator, the pressure of the evaporator may be 1 to 760 Torr, but is not limited thereto.

The temperature at the time of vapor deposition is preferably in the range of 18°C to 120°C, polymerization of the conductive polymer does not occur below 18°C, and deterioration of the polymer resin may occur at 120°C or higher.

The reaction (deposition) time during vapor deposition is preferably 0.1 hours to 48 hours, and less than 0.1 hour, the conductive polymer monomer is not uniformly polymerized in the second polymer nanofiber layer.

As the thickness of the conductive polymer layer coated on the second polymer nanofiber layer is optimized in the range of 5 nm to 50 nm, the collection efficiency of fine dust can be maximized.

The present invention provides a filter comprising the above-described nanofiber membrane.

In addition, the present invention provides a filter comprising a nanofiber membrane prepared according to the above-described method for manufacturing a nanofiber membrane.

The filter manufactured as described above may be used as a mask filter for removing fine dust, and may be used in a ventilation system or air purification filter for removing indoor pollutants such as fine dust, so that ultrafine dust can be efficiently collected. In addition, it is possible to improve the collection efficiency of fine dust compared to the differential pressure.

Hereinafter, the present invention will be described in detail by examples.

However, the following examples specifically illustrate the present invention, and the contents of the present invention are not limited by the following examples.

<Production Example>

<Production Example 1>

1-1. Preparation of the first polymer nanofiber layer

A first polymer solution in which 10 wt% of polyacrylonitrile (PAN, molecular weight 150,000) was dissolved in a dimethylformamide (DMF) solvent was prepared. The first polymer solution is fixed at a distance of 15 cm from the distal end of the spinneret of the electrospinning device to the integrated plate (support), and the voltage is 15 kV, at a flow rate of 1.0 ml/h through a single nozzle, in a grid shape A first polymer nanofiber layer was prepared by electrospinning on a mesh-shaped polypropylene (PP) support.

Subsequently, the surface of the first polymer nanofiber layer was plasma-treated under conditions of a power of 50 W, an oxygen gas injection of 50 sccm, and a chamber pressure of 100 mTorr.

The first polymer nanofiber layer treated with the plasma surface formed on the support is shown in FIG. 1.

1-2. Preparation of second polymer nanofiber layer

On the first polymer nanofiber layer, a second polymer solution obtained by dissolving 6 wt% of polyvinyl alcohol (PVA) in distilled water (solvent) and 10 wt% of FeCl ₃ as an initiator is integrated at the tip of the spinneret of the electrospinning device. The distance to the plate (the first polymer nanofiber layer) was fixed at 10 cm, and the voltage was set to 20 kV, and electrospinned at a flow rate of 0.5 ml/h through a single nozzle for 15 minutes to prepare a second polymer nanofiber layer. .

The double nanofiber layer formed on the support as described above is shown in FIG. 2.

1-3. Preparation of conductive polymer layer

Conductive polymer layer was prepared on the second polymer nanofiber layer by subjecting 3,4-ethylenedioxythiophene (EDOT) to vapor deposition polymerization for 24 hours at atmospheric pressure, 60° C., and 760 Torr.

6 shows the nanofiber membrane prepared as described above.

<Production Example 2>

2-1. Preparation of the first polymer nanofiber layer

A first polymer nanofiber layer was prepared in the same manner as in Production Example 1-1.

2-2. Preparation of second polymer nanofiber layer

Instead of electrospinning for 15 minutes in Preparation Example 1-2., a second polymer nanofiber layer was manufactured in the same manner as in Production Example 1-2.

The double nanofiber membrane formed as described above is shown in FIG. 4.

2-3. Preparation of conductive polymer layer

To the second polymer nanofiber layer, a conductive polymer layer was prepared in the same manner as in Preparation Example 1-3.

<Production Example 3>

3-2. Preparation of second polymer nanofiber layer

In Preparation Example 1, without the first polymer nanofiber layer, a second polymer nanofiber layer was prepared on a lattice-shaped mesh-like support in the same manner as in Production Example 1-2.

3-3. Preparation of conductive polymer layer

In the second polymer nanofiber layer, a conductive polymer film was prepared in the same manner as in Production Example 1-3.

The nanofibrous film formed as described above is illustrated in FIG. 14.

As shown in FIG. 14, in the case of the nanofiber membrane according to Preparation Example 3, the polymer resin is dried while moisture (solvent) buried in the nanofiber membrane is blown away at a specific temperature (60 to 120°C) generated during vapor deposition. By doing so, it can be confirmed that a hole is formed. Therefore, such a nanofiber membrane could not be used as a filter for collecting fine dust.

<Example>

The surface resistance (approximately 3 kPa) was measured with the 2 probes of the nanofiber membrane prepared in Preparation Example 1, and the applied voltage was applied from 0 to 20 V using a DC power supply. The results of measuring) are shown in Table 1 below.

1. Differential pressure (△P): refers to the pressure difference applied to the test jig equipped with a nanofiber membrane (difference between before and after the air passes through the nanofiber membrane).

2. Permeability: refers to the ratio of a volume of fluid passing through a filter at a predetermined pressure drop through a fluid medium in a certain area. The common unit of transmittance is liters per square meter per hour for each psi of pressure drop, abbreviated as LMH/psi (the higher the transmittance of the nanofiber membrane, the more transparent the nanofiber membrane is).

3. Performance Index (QF): After passing the fine dust through a test jig equipped with a nanofiber film (using a fan or vacuum pump), compare the concentration of fine dust before and after the nanofiber film and calculate it as the fine dust collection rate (E). Calculated by the formula [Performance Index (QF) = -In(1-transmittance (%)×0.01)/differential pressure] (the higher the performance index, the better the dust collection efficiency).

division Applied voltage (V) Differential pressure (Pa) Transmittance (%) Performance Index (QF) KF80 mask 0 52~56 84.2 0.03417 Preparation Example 1 0 48~54 80.0 0.032358 Preparation Example 1 10 49~53 88.9 0.043102 Preparation Example 1 20 48~54 95.4 0.060375

In the above, the present invention has been described in detail only with respect to the described embodiments, but it is apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and it is natural that such modifications and modifications belong to the appended claims.

Claims (16)

Support;
A first polymer nanofiber layer formed on the support by electrospinning and having a surface plasma-treated; And
A second polymer nanofiber layer formed on the first polymer nanofiber layer by electrospinning and having a conductive polymer coated on the surface by vapor deposition;
Including,
The conductive polymer includes polyethylene dioxythiophene,
The first polymer nanofiber layer includes polyacrylonitrile (PAN),
The second polymer nanofiber layer is a nanofiber membrane comprising polyvinyl alcohol (PVA). delete delete delete Forming a first polymer nanofiber layer by electrospinning the first polymer solution on a support;
Plasma treating the surface of the first polymer nanofiber layer;
Forming a second polymer nanofiber layer by electrospinning a second polymer solution on the plasma-treated first polymer nanofiber layer; And
Forming a conductive polymer layer by polymerizing a conductive polymer monomer on the second polymer nanofiber layer by vapor deposition;
Including,
The conductive polymer monomer includes 3,4-ethylenedioxythiophene (EDOT),
The first polymer solution includes a first polymer resin, and the first polymer resin includes polyacrylonitrile (PAN),
The second polymer solution includes a second polymer resin, and the second polymer resin is a method of manufacturing a nanofiber membrane comprising polyvinyl alcohol (PVA). delete delete The method according to claim 5,
The second polymer solution is a method of manufacturing a nano-fiber membrane further comprising an initiator. The method according to claim 8,
The initiator is Fe(NO ₃ ) ₃ , Fe(SO ₄ ) ₃ , Fe(ClO ₄ ) ₃ , Fe(NO ₂ ) _2, Ni(NO ₃ ) ₂ , Pd(NO ₃ ) ₂ , Mg(NO ₃ ) ₂ , FeCl ₃ , NiCl ₂ , CuCl ₂ , MgC _l2 , PdCl ₂ , CoCl ₂ , TiCl ₄ , TaCl ₂ , MnCl ₂ , Na(CH ₃ COOH) and Ca(CH ₃ COOH) Method of manufacturing a nano-fiber membrane comprising a. delete The method according to claim 5,
The first polymer resin is a method for producing a nano-fiber membrane contained in an amount of 2 to 25 wt% based on the total weight of the first polymer solution. The method according to claim 5,
The second polymer resin is a method for producing a nano-fiber membrane contained in an amount of 2 to 25 wt% based on the total weight of the second polymer solution. The method according to claim 5,
The applied voltage of the electrospinning is 10 to 25 kV, the flow rate is 0.1 to 1.5 ml / h manufacturing method of the nano-fiber membrane. The method according to claim 5,
The vapor deposition is 1 to 760 torr, 18 ℃ to 120 ℃, the manufacturing method of the nano-fiber film is performed for 0.1 to 48 hours. A filter comprising the nanofiber membrane according to claim 1. A filter comprising a nanofiber membrane prepared according to any one of claims 5, 8, 9, and 11-14.

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