CN113832706B - An in-situ water electret method based on electrospinning and fiber materials with charge bubbles - Google Patents

Abstract

The invention belongs to the technical field of fiber materials, and discloses an in-situ water electret method based on electrostatic spinning and a fiber material with charge bubbles. The in-situ water electret method refers to the use of high pressure to atomize water during the electrospinning process, and charges will be generated between water molecules and the high-speed flying charged jet due to the friction effect, and then realized when the jet phase is separated and solidified into fibers. In situ electret of fibers. The resulting fiber material with charge bubbles has a closed cell structure inside, and charges of opposite polarity are accumulated on the opposite sides of the cells to form polar charge bubbles, and the charges injected into the polar charge bubbles and fiber entities will be vectorially superimposed , forming a single fiber with a significant electrostatic electret effect, the surface potential of the fiber membrane is controllable in the range of 0.05-1kV, and the charge bubble structure makes the electret effect extremely stable.

Description

An in-situ water electret method based on electrospinning and fibers with charge bubbles Material

technical field

The invention belongs to the technical field of fiber materials, and discloses an in-situ preparation technology of electret fibers, in particular an in-situ water electret method based on electrostatic spinning and a fiber material with charge bubbles. Specifically, in the electrospinning process, the high-pressure atomized water molecules and the high-speed flying charged jets generate charges due to friction, on the one hand, the in-situ electret of the fibers is realized, and on the other hand, the water molecules The introduction will synchronously generate the charge bubble structure. The in-situ electret and the closed cell structure inside the fiber promote each other, making the electret effect of the fiber significant and stable, which can realize the controllable preparation of high-efficiency air filter materials.

Background technique

Air filter materials have become a hot research topic in recent years. Melt-blown non-woven materials have become one of the currently commonly used non-woven filter materials due to their dense web structure, high porosity, and good processing performance. Electret treatment of melt-blown non-woven materials can greatly increase its electrostatic adsorption to submicron particles. The existing electret products on the market are mainly melt-blown non-woven fabrics processed by water electret technology. Although the processing technology It has become more and more mature, but still faces the following problems. First, the existing material water electret process is lengthy, high cost, low work efficiency, and prone to secondary pollution; secondly, the fiber forming process is separated from the electret process, and the electret depth is relatively low. Shallow, resulting in unstable electret effect and reducing the service life of the material; finally, the fiber diameter of the existing material is on the order of microns, resulting in a large pore size and low filtration efficiency for fine particles. It is urgent to develop a new type of air filter with a simple process fiber material.

Based on the electrospinning technology, the present invention regulates a fiber material with charge bubbles, and performs in-situ water electret on it during the electrospinning process, which is a new invention and creation in the field of air filtration. The technologies closely related to the present invention are mainly obtained by searching keywords "water electret & nonwoven fabric", "electrospinning & cell structure", "air filtration & fiber". In the disclosed technology, commonly used non-woven filter materials have not yet achieved in-situ electret, resulting in shallow electret depth and fast static decay. The existing non-woven filter material water electret process is often realized through an independent processing system, such as "CN202023021710.2 A kind of water electret treatment equipment", "CN202011291253.0 Processing method of water electret melt-blown cloth and water spray device", "CN202011602015.7 A kind of melt-blown water electret system", etc., all use independent systems to Nonwovens are treated with water electret. In the technology of preparing air filter material by electrospinning technology, "CN201810192704.1 A Preparation Method of Superhydrophobic Electret Filter Material for Air Purification" discloses a composite filter material without pores structure, the filter material is complicated to prepare and the electret depth is shallow, which is essentially different from the material and preparation method of this patent. Among the disclosed air filter fibers, there is no material that enhances electret performance with a cell structure. We propose a fiber material with charge bubbles, which has a closed cell structure inside, which can increase the specific surface area of the fiber and increase the charge density of the electret, and the opposite polarity charges are accumulated on the opposite side of the cells to form a polar charge. Bubbles, polar charge bubbles and charge vectors of fiber entities are superimposed to form a fiber material with significant and stable electrostatic electret effect.

Contents of the invention

The purpose of the present invention is to provide a kind of in-situ water electret method based on electrospinning, and described in-situ water electret method refers to utilize high pressure to atomize water in electrospinning process, water molecule and high-speed flying Charges will be generated between the charged jets due to friction, and then electret in situ when the jets are phase-separated and solidified into fibers.

As a preferred technical solution:

As mentioned above, an in-situ water electret method based on electrospinning, there is a ring-shaped water spray device on the periphery of the jet flight or a certain amount of water is directly added to the spinning solution, and the water molecules are subjected to high pressure or high voltage. Atomization, the angle between the macro motion direction of the atomized water molecules and the motion direction of the high-speed charged jet is 0-90°. The particle size of atomized water molecules is in the range of 60-300 μm. Water can be ultrapure water, deionized water, double distilled water, pure water, distilled water.

A kind of in-situ water electret method based on electrospinning as mentioned above, the main component of fiber can be polyvinylidene fluoride, polyvinyl chloride, polyacrylonitrile, polycarbonate, polyetherimide, polystyrene Or polyurethane, its form is powdery, liquid, and its molecular weight is 10000～900000; Described solvent can be N-N dimethylformamide, N-N dimethylacetamide, acetone, butanone, tetrahydrofuran, dichloromethane and One or more than two kinds of methylpyrrolidones are mixed to form a colloid solution with a mass concentration of 15-40 wt%, which is prepared by electrospinning.

An in-situ water electret method based on electrospinning as described above, the common process conditions of the electrospinning are: voltage 10-30KV, receiving distance 5-25cm, injection speed 1-5mL/h, temperature 0 ～35℃, relative humidity 85～99%, spinning time 0.5～3h.

The present invention also proposes a fiber material with charge bubbles. The resulting fiber material with charge bubbles has a closed cell structure inside, and charges of opposite polarity are accumulated on the opposite sides of the cells to form polar charge bubbles. The charge vectors of polar charge bubbles and fiber entities are superimposed to form a single fiber with significant electrostatic electret effect. Its surface potential is controllable in the range of 0.05-1kV, and the electret effect is highly stable.

As a preferred technical solution:

As mentioned above, an in-situ water electret method based on electrospinning and fiber materials with charge bubbles, the stability of the electret effect is shown as the surface potential decay rate after 10 days of treatment in a high humidity (≥80%) environment. <5%.

According to the above-mentioned in-situ water electret method based on electrospinning and the fiber material with charge bubbles, the cell structure is regularly or irregularly distributed inside the fiber, and the cell diameter is in the range of 20-200nm. The number of cells is 10-100/m ² , the cell depth is 10-500 nm, and the distance between adjacent cells is 10-100 nm. The grammage of the fiber membrane is 100-350g/m ² , and the thickness is 1-10mm; the nanofiber diameter of the nanofiber layer is between 100-900nm, the grammage of the nanofiber layer is 0.01-5g/m ² , and the pores Rate ≥ 85%.

Description of drawings

Figure 1: Schematic diagram of a fiber with charge bubbles: the fiber has a closed cell structure inside, and the cells generate potential separation under high voltage, and the electric field of each charge bubble and the electric field vector of the fiber entity are superimposed to form an electret fiber.

Beneficial effect

An in-situ water electret method based on electrospinning and fiber materials with charge bubbles of the present invention have advantages in terms of performance, environmental protection and cost: water molecules after high-pressure atomization and high-speed flying charged jets Charges are generated due to friction, and then in-situ electret in the electrospinning process can solve the problems of long, high cost and low work efficiency in the original water electret process; there is no traditional water electret in the in-situ water electret process The water treatment part of the process can not only reduce the waste of water resources, but also has no waste water discharge, which is environmentally friendly; the use of electrospinning technology can reduce the fiber diameter to the order of nanometers and improve the filtration efficiency of fine particles.

The invention proposes a fiber material based on electrospinning with charge bubbles, which has the advantages of convenient operation, controllable process, low cost, etc., and the material structure is highly adjustable and the electret effect is remarkable. By adjusting the spinning parameters, it can Fiber materials with charge bubbles are obtained. Nano-scale fibers have a relatively high specific surface area, which can deposit as much charge as possible on the surface and inside of the fiber, increase the charge density of the electret, and have a closed cell structure inside. Charges of opposite polarity are accumulated on the opposite sides of the cells to form polar charge bubbles. This cell structure further increases the specific surface area of the fiber and greatly increases the amount of charge that the fiber can accommodate. In the one-step electret process of electrospinning, Form a fiber material with significant and stable electrostatic electret effect, thereby prolonging the service life of the filter material.

To sum up, the method and material provided by the present invention are of value in promoting the upgrading of air filter materials.

Detailed ways

The present invention will be further described below in combination with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

In this embodiment, an in-situ water electret method based on electrospinning, there is a ring-shaped water spray device on the periphery of the jet flight to apply high pressure to atomize the water molecules, and the macroscopic movement direction of the atomized water molecules and the high-speed flight The angle between the moving directions of the charged jets is 10°; the particle size of the atomized water molecules is 80 μm; the water is ultrapure water; the main component of the fiber is polyvinylidene fluoride, the form is powder, the molecular weight is 50000, the solvent It is N-N dimethylformamide, and the mass concentration of the formed colloid solution is 20wt%; the process conditions of electrospinning are: voltage 18KV, receiving distance 20cm, injection speed 1mL/h, temperature 20°C, relative humidity 87%, spinning Silk time 1h.

Example 2

In this embodiment, an in-situ water electret method based on electrospinning, there is a ring-shaped water spray device on the periphery of the jet flight to apply high pressure to atomize the water molecules, and the macroscopic movement direction of the atomized water molecules and the high-speed flight The angle between the moving directions of the charged jets is 30°; the particle size of the atomized water molecules is 100 μm; the water is deionized water; the main component of the fiber is polycarbonate, the form is powder, the molecular weight is 100,000, and the solvent is Acetone, the mass concentration of the formed colloid solution is 23wt%; the process conditions of electrospinning are: voltage 25KV, receiving distance 20cm, injection speed 3mL/h, temperature 30°C, relative humidity 90%, spinning time 1h.

Example 3

In this embodiment, an in-situ water electret method based on electrospinning, when the aqueous spinning solution flows out from a needle with high-voltage static electricity, the water molecules are broken into fine droplets or jets under the action of high-voltage electricity, The fiber is electretized by friction with the nanofiber, and the water content in the spinning solution is 10%. The particle size of the atomized water molecule is 80 μm; the water is deionized water; the main component of the fiber is polyvinyl chloride, the form is liquid, the molecular weight is 30000, the solvent is tetrahydrofuran, and the mass concentration of the formed colloidal solution is 30wt%; The spinning process conditions are: voltage 18KV, receiving distance 20cm, injection speed 2mL/h, temperature 25°C, relative humidity 95%, spinning time 1h.

Example 4

In this embodiment, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, a ring-shaped water spray device on the periphery of the jet flight is used to atomize water molecules under high pressure, and the atomized water The angle between the direction of molecular macroscopic movement and the direction of movement of the high-speed charged jet is 30°; the particle size of atomized water molecules is 200 μm; the water is double distilled water; the main component of the fiber is polyvinylidene fluoride, and the form is powder shape, the molecular weight is 200000, the solvent is a mixed liquid in N-N dimethylformamide and methylpyrrolidone, and the mass concentration of the formed colloidal solution is 25wt%; the process conditions of electrospinning are: voltage 20KV, receiving distance 20cm, injection The speed is 1.5mL/h, the temperature is 30°C, the relative humidity is 90%, and the spinning time is 1h.

Example 5

In this embodiment, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, a ring-shaped water spray device on the periphery of the jet flight is used to atomize water molecules under high pressure, and the atomized water The angle between the direction of molecular macroscopic movement and the direction of movement of the high-speed charged jet is 50°; the particle size of the atomized water molecule is 220 μm; the water is distilled water; the main component of the fiber is polyacrylonitrile, the form is liquid, the molecular weight is 300000, the solvent is N-N dimethylformamide, and the mass concentration of the formed colloidal solution is 34wt%. The humidity is 88%, and the spinning time is 1h.

Example 6

In this embodiment, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, a ring-shaped water spray device on the periphery of the jet flight is used to atomize water molecules under high pressure, and the atomized water The angle between the direction of molecular macroscopic movement and the direction of movement of the high-speed charged jet is 45°; the particle size of the atomized water molecules is 200 μm; the water is ultrapure water; the main component of the fiber is polycarbonate, and the form is powder , the molecular weight is 200000, the solvent is N-N dimethylacetamide, and the mass concentration of the formed colloidal solution is 35wt%; the process conditions of electrospinning are: voltage 25KV, receiving distance 20cm, injection speed 1.5mL/h, temperature 30°C , relative humidity 90%, spinning time 1h.

Example 7

In this example, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, when the aqueous spinning solution flows out from a needle with high-voltage static electricity, the water molecules are broken under the action of high-voltage electricity Form into fine droplets or jets, rub against the nanofibers to electret the fibers, and the water content in the spinning solution is within 15%. The particle size of atomized water molecules is 100 μm; the water is ultrapure water; the main component of the fiber is polyvinyl chloride, the form is powder, the molecular weight is 30000, the solvent is acetone, and the mass concentration of the formed colloidal solution is 32wt%; The spinning process conditions are: voltage 20KV, receiving distance 20cm, injection speed 1mL/h, temperature 30°C, relative humidity 90%, and spinning time 1h.

Example 8

In this embodiment, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, a ring-shaped water spray device on the periphery of the jet flight is used to atomize water molecules under high pressure, and the atomized water The angle between the direction of molecular macroscopic movement and the direction of movement of the high-speed charged jet is 60°; the particle size of atomized water molecules is 80 μm; the water is pure water; the main component of the fiber is polyvinylidene fluoride, and the form is powder , the molecular weight is 100000, the solvent is methylpyrrolidone, and the mass concentration of the formed colloidal solution is 30wt%; the process conditions of electrospinning are: voltage 18KV, receiving distance 20cm, injection speed 1.5mL/h, temperature 30°C, relative humidity 90%, spinning time 1h.

Example 9

In this example, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, when the aqueous spinning solution flows out from a needle with high-voltage static electricity, the water molecules are broken under the action of high-voltage electricity Form into fine droplets or jets, rub against the nanofibers to electret the fibers, and the water content in the spinning solution is 15%. The particle size of atomized water molecules is 150 μm; the water is ultrapure water; the main component of the fiber is polyvinylidene fluoride, the form is liquid, the molecular weight is 200,000, the solvent is acetone, and the mass concentration of the formed colloidal solution is 30wt%; The process conditions of electrospinning are: voltage 20KV, receiving distance 20cm, injection speed 1mL/h, temperature 25°C, relative humidity 89%, spinning time 1h.

Example 10

In this embodiment, an in-situ water electret method based on electrospinning and a fiber material with charge bubbles, a ring-shaped water spray device on the periphery of the jet flight is used to atomize water molecules under high pressure, and the atomized water The angle between the direction of molecular macroscopic movement and the direction of movement of the high-speed charged jet is 30°; the particle size of atomized water molecules is 100 μm; the water is pure water; the main component of the fiber is polyetherimide, and the form is powder shape, the molecular weight is 600000, the solvent is dichloromethane, and the mass concentration of the formed colloid solution is 30wt%; the process conditions of electrospinning are: voltage 20KV, receiving distance 18cm, injection speed 1.5mL/h, temperature 0～35℃ , relative humidity 90%, spinning time 1h.

Example 11

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.5kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential attenuation rate was 3%; the cell structure was regularly distributed inside the fiber, the cell diameter was 50nm, the cell number was 20/m ² , the cell depth was 50nm, and the The distance is 80nm; the weight of the fiber membrane is 120g/m ² , and the thickness is 3mm; the nanofiber diameter of the nanofiber layer is 150nm, the weight of the nanofiber layer is 0.5g/m ² , and the porosity is 85%.

Example 12

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.6kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential decay rate was 2%; the cell structure was irregularly distributed inside the fiber, the cell diameter was 70nm, the cell number was 60/m ² , the cell depth was 30nm, and the The distance is 45nm; the weight of the fiber membrane is 150g/m ² and the thickness is 4mm; the nanofiber diameter of the nanofiber layer is between 300nm, the weight of the nanofiber layer is 1g/m ² , and the porosity is 90%.

Example 13

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.8kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential attenuation rate was 3%; the cell structure was irregularly distributed inside the fiber, the cell diameter was 100nm, the cell number was 40/m ² , the cell depth was 200nm, and the The distance is 30nm; the weight of the fiber membrane is 250g/m ² , and the thickness is 3.5mm; the nanofiber diameter of the nanofiber layer is 350nm, the weight of the nanofiber layer is 0.5g/m ² , and the porosity is 85%.

Example 14

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.6kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential attenuation rate was 3%; the cell structure was distributed irregularly inside the fiber, the cell diameter was 100nm, the cell number was 50/m ² , the cell depth was 350nm, and the The distance is 40nm; the weight of the fiber membrane is 180g/m ² and the thickness is 8mm; the nanofiber diameter of the nanofiber layer is 450nm, the weight of the nanofiber layer is 3g/m ² , and the porosity is 85%.

Example 15

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.3kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential decay rate was 3.5%; the cell structure was regularly distributed inside the fiber, the cell diameter was 180nm, the cell number was 65/m ² , the cell depth was 330nm, and the The distance is 25nm; the weight of the fiber membrane is 200g/m ² and the thickness is 3mm; the nanofiber diameter of the nanofiber layer is between 550nm, the weight of the nanofiber layer is 0.6g/m ² , and the porosity is 88%.

Example 16

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.7kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential decay rate was 2.5%; the cell structure was distributed irregularly inside the fiber, the cell diameter was 170nm, the cell number was 30/m ² , the cell depth was 350nm, and the The distance is 40nm; the weight of the fiber membrane is 170g/m ² , and the thickness is 3mm; the nanofiber diameter of the nanofiber layer is 550nm, the weight of the nanofiber layer is 1.8g/m ² , and the porosity is 90%.

Example 17

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.85kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential decay rate was 2%; the cell structure was irregularly distributed inside the fiber, the cell diameter was 130nm, the cell number was 65/m ² , the cell depth was 430nm, and the The distance is 54nm; the weight of the fiber membrane is 280g/m ² , and the thickness is 4mm; the nanofiber diameter of the nanofiber layer is 750nm, the weight of the nanofiber layer is 3.5g/m ² , and the porosity is 90%.

Example 18

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.75kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential decay rate was 2.5%; the cell structure was distributed irregularly inside the fiber, the cell diameter was 100nm, the cell number was 75/m ² , the cell depth was 300nm, and the The distance is 68nm; the weight of the fiber membrane is 240g/m ² , and the thickness is 4.5mm; the nanofiber diameter of the nanofiber layer is 780nm, the weight of the nanofiber layer is 0.3g/m ² , and the porosity is 85%.

Example 19

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.7kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the decay rate of the surface potential was 3.7%; the cell structure was distributed regularly or irregularly inside the fiber, the cell diameter was 180nm, the cell number was 25/m ² , the cell depth was 30nm, and the adjacent cell The distance between the pores is 89nm; the weight of the fiber membrane is 200g/m ² , and the thickness is 4mm; the diameter of the nanofibers in the nanofiber layer is between 300nm, the weight of the nanofiber layer is 0.5g/m ² , and the porosity is 90%.

Example 20

In this embodiment, a fiber material with significant electret effect and charge bubbles, the characteristic parameters of the electret effect: the surface potential is 0.8kV, and the stability of the electret effect is shown in a high humidity (≥80%) environment After 10 days of treatment, the surface potential decay rate is 2%; the cell structure is distributed regularly or irregularly inside the fiber, the cell diameter is 130nm, the cell number is 30/m ² , the cell depth is 200nm, and the adjacent cell The distance between the pores is 90nm; the weight of the fiber membrane is 250g/m ² and the thickness is 3mm; the nanofiber diameter of the nanofiber layer is 200nm, the weight of the nanofiber layer is 0.5g/m ² , and the porosity is 88% .

Claims (8)

1. a kind of in-situ water electret method based on electrospinning, it is characterized in that: described in-situ water electret method refers to utilizing high pressure to carry out atomization to water in electrospinning process, water molecule and high-speed flying Charges will be generated due to friction between the charged jets, and then the in-situ electret of the fibers will be realized when the jets are phase-separated and solidified into fibers; There is a ring-shaped water spray device on the periphery of the jet flight, and high pressure is applied to the water spray device to atomize the water molecules. The angle between the macroscopic motion direction of the atomized water molecules and the motion direction of the high-speed charged jet is 0-90° ; The relative humidity of electrospinning is 85-99%. 2. The in-situ water electret method according to claim 1, characterized in that the particle size of the atomized water molecules is within the range of 60-300 μm, and the water is selected from ultrapure water, deionized water, double distilled water, pure water, distilled water. 3. in-situ water electret method according to claim 1, is characterized in that, polymer is selected from polyvinylidene fluoride, polyvinyl chloride, polyacrylonitrile, polycarbonate, polyetherimide, polystyrene Or polyurethane, its form is powdery, liquid, its molecular weight is 10000～900000; The solvent is selected from N-N dimethylformamide, N-N dimethylacetamide, acetone, butanone, tetrahydrofuran, methylene chloride and methylpyrrolidone One or more of them are mixed to form a colloid solution with a mass concentration of 15-40 wt%, which is prepared by electrospinning. 4. The in-situ water electret method according to claim 1, wherein the process conditions of the electrospinning are: voltage 10-30KV, receiving distance 5-25cm, injection speed 1-5mL/h, temperature 0～35℃, spinning time 0.5～3h. 5. The in-situ water electret method according to claim 1, characterized in that, in the in-situ water electret process, the introduction of water molecules will have an impact on polymer jet phase separation, thereby producing fibers with charge bubbles, The inside of the fiber has a closed hole structure and a long-term electret effect. 6. According to the fiber material with charge bubble obtained by the in-situ water electret method described in any one of claims 1 to 5, it is characterized in that the opposite polarity charge is accumulated on the opposite side of the cell to form a polar charge bubble , the charge vectors of polar charge bubbles and fiber entities are superimposed to form a single fiber with significant and stable electret effect. The characterization parameters of the electret effect: the surface potential is 0.05 ~ 1kV, and the stability of the electret effect is manifested at humidity ≥ 80 % Treated in the environment for 10 days, the surface potential decay rate <5%. 7. The fiber material according to claim 6, characterized in that, the cell structure is distributed regularly or irregularly inside the fiber, the cell diameter is in the range of 20-200 nm, and the cell number is 10-100 /m ² , the cell depth is 10-500 nm, and the distance between adjacent cells is 10-100 nm. 8. The fiber material according to claim 6, characterized in that, the weight of the fiber membrane is 100-350g/m ² , and the thickness is 1-10mm; the diameter of the nanofibers in the nanofiber layer is between 100-900nm, nanometer The weight of the fiber layer is 0.01-5g/m ² , and the porosity is ≥85%.