CN110591137A - A method for hydrophilic modification of polyurethane carrier surface - Google Patents

Abstract

The invention discloses a method for hydrophilic modification of the surface of a polyurethane carrier, which comprises the following steps: step S1, carrying out plasma surface treatment on the polyurethane carrier to obtain a polyurethane carrier subjected to plasma surface treatment; step S2, contacting the polyurethane carrier subjected to the plasma surface treatment in the step S1 with a polycation solution to perform polycation solution treatment to obtain a polycation modified polyurethane carrier; and step S3, contacting the polycation-modified polyurethane carrier obtained in step S2 with a polyanion solution to perform polyanion solution treatment to obtain the polyanion-modified polyurethane carrier. According to the invention, the polyurethane carrier is subjected to plasma surface treatment and then sequentially contacted with the polycation solution and the polyanion solution to alternately perform layer-layer self-assembly, so that the surface modification of the polyurethane carrier is realized, and the modified polyurethane carrier has good hydrophilicity and stability.

Description

A method for hydrophilic modification of polyurethane carrier surface

technical field

The invention belongs to the technical field of polymer carrier modification, and in particular relates to a method for hydrophilic modification of the surface of a polyurethane carrier.

Background technique

With the development of economy and society, the country has higher and higher requirements for chemical sewage discharge, and the demand for new water treatment technologies has also increased. Chemical sewage has the characteristics of high pollutant concentration and complex composition. It is difficult for traditional sewage treatment methods to meet the requirements for the treatment effect of sewage. The method of adding suspended filler to the aeration tank can make a large number of microorganisms attach to the filler to form a biofilm, which can effectively improve the efficiency of sewage treatment.

Polyurethane is a polymer made of polyisocyanate, polyether polyol or polyester polyol, small molecule polyol, polyamine and other raw materials. It has the characteristics of large specific surface area, suitable for microbial attachment, stable properties, and good wear resistance. , but conventional polyurethane fillers generally have a hydrophobic surface, and the contact angle is usually greater than 100°, which makes the efficiency of microbial film formation low. Hydrophilic modification of the surface of the filler can improve the efficiency of microbial film formation. Therefore, hydrophilic modification of the polyurethane surface It is one of the current research hotspots.

Plasma surface treatment technology is a new means of surface modification. Plasma surface treatment refers to a technology in which the surface of a material interacts with active particles in the plasma in a non-polymerizing gas plasma to modify the surface of the material. . The energy of the particles in the plasma is generally greater than the bond energy of the polymer material, which can completely break the chemical bonds of the organic macromolecules and form new bonds; but it is far lower than the high-energy radioactive rays, so the modification only involves the surface of the material without affecting the matrix. performance. The hydrophilicity, cohesiveness, and biocompatibility of materials treated by plasma will be improved. However, the effect of only using plasma to modify the surface of the material will decay with time, and the surface properties of the material are unstable.

Contents of the invention

In order to improve the hydrophilicity of the polyurethane surface, the present invention provides a method for the surface hydrophilic modification of the polyurethane carrier, by placing the polyurethane carrier in a plasma gas atmosphere for plasma surface treatment, and then sequentially reacting with polycation solution and poly The anionic solution contacts alternately to carry out layer-layer self-assembly to realize the surface modification of the polyurethane carrier, and the modified polyurethane carrier has good hydrophilicity and stability.

The object of the present invention is achieved by the following technical scheme, a method for hydrophilic modification of polyurethane carrier surface, comprising:

Step S1, subjecting the polyurethane carrier to plasma surface treatment to obtain a plasma surface-treated polyurethane carrier;

Step S2, contacting the plasma-surface-treated polyurethane carrier obtained in step S1 with a polycation solution for polycation solution treatment to obtain a polycation-modified polyurethane carrier;

Step S3, contacting the polycation-modified polyurethane carrier obtained in step S2 with a polyanion solution to treat the polyanion solution to obtain a polyanion-modified polyurethane carrier.

According to a preferred embodiment of the present invention, step S4 is further included after step S3, and the polycation solution treatment of step S2 and the polyanion solution treatment process of step S3 are repeated for 2-20 times, preferably 5-12 times.

According to a preferred embodiment of the present invention, before the polyurethane carrier is subjected to plasma surface treatment, the polyurethane carrier is subjected to surface cleaning treatment.

In a preferred embodiment of the present invention, the polyurethane carrier surface is cleaned by using absolute ethanol and/or deionized water to clean the polyurethane carrier and drying it.

According to a preferred embodiment of the present invention, the plasma surface treatment is that the polyurethane carrier is placed in a plasma treatment device, and a plasma gas is introduced to perform the plasma surface treatment.

According to a preferred embodiment of the present invention, the plasma gas is a plasma gas of one or more substances selected from air, oxygen, nitrogen, ammonia, argon, acrylic acid and allylamine.

According to a preferred embodiment of the present invention, the pressure of the plasma gas is 20-80Pa, preferably 50-70Pa.

According to a preferred embodiment of the present invention, the plasma surface treatment time is 10-100 min, preferably 10-30 min.

According to a preferred embodiment of the present invention, the power of the plasma processing device is 10-300W, preferably 50-150W.

According to a preferred embodiment of the present invention, the polycation solution is selected from one or more of polydiallyldimethylammonium chloride solution, cationic polyacrylamide solution and chitosan solution, preferably poly The concentration of the cationic solution is 0.01-0.1mmol/L.

According to a preferred embodiment of the present invention, the polyanion solution is selected from one or more of polystyrene sodium sulfonate solution, sodium alginate solution and polyacrylic acid solution, preferably, the concentration of the polyanion solution is 0.01- 0.1mmol/L.

According to a preferred embodiment of the present invention, in step S2, the method of contacting the polyurethane carrier with the polycation solution is to impregnate the polyurethane carrier with the polycation solution, preferably, the time of immersion is 15-60min, and/or, the temperature of immersion is 2-6°C. Preferably, after impregnating the polyurethane carrier with the polycation solution, the polyurethane carrier is taken out for cleaning and drying. Preferably, the drying method is cold air drying, and the temperature of the cold air is preferably 1-5°C. In a preferred embodiment of the invention, the polyurethane carrier is washed with deionized water to remove excess polycation solution on the polyurethane carrier.

According to a preferred embodiment of the present invention, in step S3, the method of contacting the polyurethane carrier with the polyanion solution is to impregnate the polyurethane carrier with the polyanion solution, preferably, the time of immersion is 15-60min, and/or, the temperature of immersion is 2-6°C. Preferably, after impregnating the polyurethane carrier with the polyanion solution, the polyurethane carrier is taken out for cleaning and drying. Preferably, the drying method is cold air drying, and the temperature of the cold air is preferably 1-5°C. In a preferred embodiment of the invention, the polyurethane carrier is washed with deionized water to remove excess polyanion solution on the polyurethane carrier.

According to a preferred embodiment of the present invention, the polyurethane carrier is selected from a polyurethane film and/or a porous polyurethane carrier.

In the present invention, "the solution of polycation" and "the concentration of polyanion solution" and relevant description refer to the concentration of structural unit in the polymer, for example, the concentration of polystyrene sodium sulfonate solution refers to structural unit styrene sulfonic acid Sodium concentration.

In the method for hydrophilic modification of the surface of the polyurethane carrier of the present invention, after the polyurethane carrier is subjected to plasma surface treatment, the surface contact angle becomes significantly smaller, showing a certain degree of hydrophilicity, and then the polyurethane carrier is subjected to layer-by-layer self-assembly technology. Surface modification, immobilizing polyanions and polycations on the surface of the carrier, further improving the hydrophilicity of the surface of the carrier, this method is simple, flexible, and easy to operate. Compared with only plasma treatment, the hydrophilicity of the surface of the material can be improved. It is further improved, and the modified polyurethane carrier has better stability, and the contact angle does not change significantly after a period of time. The modified hydrophilic polyurethane carrier is more conducive to the attachment and growth of microorganisms in the field of sewage treatment. Compared with the existing polyurethane surface modification technology, the method described in the present invention can carry out directional design modification on the surface of the carrier according to the needs, which has important practical application significance, and the reaction time of the modification process is short, the modification effect is good, It is not easy to produce pollution and is easy to industrialized production.

Description of drawings

Figure 1 shows the surface contact angle (left) and surface contact angle after modification (right) of the polyurethane film of Example 4 of the present invention before modification.

Detailed ways

The present invention will be described in detail below in conjunction with the examples, but the present invention is not limited by the following examples.

Example 1

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 10 Pa, inject argon plasma gas, and adjust the pressure in the reactor to 50 Pa. After stabilization, start the high-frequency power supply, the processing power is 100W, and the processing time is 20min;

(3) Put the surface-treated polyurethane film into a polydiallyldimethylammonium chloride solution with a concentration of 0.01mmol/L, and soak for 15min at an adsorption temperature of 3°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 1°C;

(4) Put the polyurethane film into a 0.05 mmol/L sodium polystyrene sulfonate solution at an adsorption temperature of 4° C. and soak for 20 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 1°C;

(5) Repeat step (3) and step (4) 10 times in sequence to complete the layer-by-layer self-assembly process to obtain a hydrophilic modified polyurethane film.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment and layer-by-layer self-assembly, the contact angle was 49.6°, and after one month, the contact angle was 51.2°.

Example 2

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 5 Pa, and inject argon plasma gas to adjust the pressure in the reactor to 70 Pa. After stabilization, start the high-frequency power supply, the processing power is 200W, and the processing time is 25min;

(3) Put the surface-treated polyurethane film into a cationic polyacrylamide solution with a concentration of 0.05mmol/L, and soak for 60min at an adsorption temperature of 2°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 4°C;

(4) Put the polyurethane film into a 0.1 mmol/L sodium polystyrene sulfonate solution at an adsorption temperature of 2° C. and soak for 60 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 4°C;

(5) Repeat step (3) and step (4) 10 times in sequence to complete the layer-by-layer self-assembly process and obtain a modified polyurethane film.

The contact angle of the unmodified polyurethane film was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 41.4°. After one month, its contact angle was measured to be 43.5°.

Example 3

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 8 Pa, and inject argon plasma gas to adjust the pressure in the reactor to 20 Pa. After stabilization, start the high-frequency power supply, the processing power is 50W, and the processing time is 10min;

(3) Put the surface-treated polyurethane film into a chitosan solution with a concentration of 0.05mmol/L, and soak for 30min at an adsorption temperature of 6°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(4) Put the polyurethane film into 0.01 mmol/L sodium polystyrene sulfonate solution at an adsorption temperature of 5° C. and soak for 15 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(5) Repeat step (3) and step (4) twice in sequence to complete the layer-by-layer self-assembly process, and obtain a modified polyurethane film.

The contact angle of the unmodified polyurethane film is 117°, and the contact angle after plasma surface treatment + layer by layer self-assembly is 76.5°. After one month, its contact angle was measured to be 78.9°.

Example 4

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 7Pa, and inject argon plasma gas to adjust the pressure in the reactor to 40Pa. After stabilization, start the high-frequency power supply, the processing power is 10W, and the processing time is 15min;

(3) Put the surface-treated polyurethane film into a polydiallyldimethylammonium chloride solution with a concentration of 0.1mmol/L, and soak for 20min at an adsorption temperature of 4°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 1°C;

(4) Put the polyurethane film into a 0.05 mmol/L sodium alginate solution at an adsorption temperature of 6° C. and soak for 30 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 1°C;

(5) Steps (3) and (4) were repeated six times in sequence to complete the layer-by-layer self-assembly process to obtain a modified polyurethane film.

The contact angle of the unmodified polyurethane film was 117°, and the contact angle after plasma surface treatment + layer-by-layer self-assembly was 62.9°. After one month, its contact angle was measured to be 65.1°.

Example 5

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 10 Pa, inject argon plasma gas, and adjust the pressure in the reactor to 80 Pa. After stabilization, start the high-frequency power supply, the processing power is 150W, and the processing time is 30min;

(3) Put the surface-treated polyurethane film into a cationic polyacrylamide solution with a concentration of 0.01 mmol/L, and soak for 40 minutes at an adsorption temperature of 2°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(4) Put the polyurethane film into a 0.05 mmol/L polyacrylic acid solution at an adsorption temperature of 2° C. and soak for 40 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(5) Steps (3) and (4) were repeated 8 times in sequence to complete the layer-by-layer self-assembly process, and a modified polyurethane film was obtained.

The contact angle of the unmodified polyurethane film was 117°, and the contact angle after plasma surface treatment + layer by layer self-assembly was 54.7°. After one month, its contact angle was measured to be 59.2°.

Example 6

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 5 Pa, inject argon plasma gas, and adjust the pressure in the reactor to 60 Pa. After stabilization, start the high-frequency power supply, the processing power is 300W, and the processing time is 25min;

(3) Put the surface-treated polyurethane film into a polydiallyldimethylammonium chloride solution with a concentration of 0.01mmol/L, and soak for 50min at an adsorption temperature of 5°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(4) Put the polyurethane film into a 0.05 mmol/L polyacrylic acid solution at an adsorption temperature of 3° C. and soak for 25 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(5) Steps (3) and (4) were repeated four times in sequence to complete the layer-by-layer self-assembly process to obtain a modified polyurethane film.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer-by-layer self-assembly, the contact angle was 69.5°. After one month, its contact angle was measured to be 72.3°.

Example 7

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 5 Pa, and inject argon plasma gas to adjust the pressure in the reactor to 70 Pa. After stabilization, start the high-frequency power supply, the processing power is 150W, and the processing time is 20min;

(3) Put the surface-treated polyurethane film into a cationic polyacrylamide solution with a concentration of 0.1 mmol/L, and soak for 35 minutes at an adsorption temperature of 2°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(4) Put the polyurethane film into a 0.01 mmol/L sodium alginate solution at an adsorption temperature of 3° C. and soak for 30 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(5) Steps (3) and (4) were repeated seven times in sequence to complete the layer-by-layer self-assembly process to obtain a modified polyurethane film.

The contact angle of the unmodified polyurethane film was 117°, and the contact angle after plasma surface treatment + layer-by-layer self-assembly was 51.2°. After one month, its contact angle was measured to be 53.5°.

Example 8

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 10 Pa, inject argon plasma gas, and adjust the pressure in the reactor to 70 Pa. After stabilization, start the high-frequency power supply, the processing power is 250W, and the processing time is 30min;

(3) Put the surface-treated polyurethane film into a chitosan solution with a concentration of 0.05mmol/L, and soak for 25min at an adsorption temperature of 3°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(4) Put the polyurethane film into a 0.1 mmol/L sodium alginate solution at an adsorption temperature of 4° C. and soak for 35 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(5) Steps (3) and (4) were repeated nine times in sequence to complete the layer-by-layer self-assembly process to obtain a modified polyurethane film.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 43.4°. After one month, measure its contact angle and be 45.8 °.

Example 9

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 5 Pa, and inject argon plasma gas to adjust the pressure in the reactor to 50 Pa. After stabilization, start the high-frequency power supply, the processing power is 100W, and the processing time is 20min;

(3) Put the surface-treated polyurethane film into a chitosan solution with a concentration of 0.01 mmol/L, and soak for 30 min at an adsorption temperature of 3° C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(4) Put the polyurethane film into a 0.01 mmol/L polyacrylic acid solution at an adsorption temperature of 2° C. and soak for 45 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 2°C;

(5) Steps (3) and (4) were repeated six times in sequence to complete the layer-by-layer self-assembly process to obtain a modified polyurethane film.

The contact angle of the unmodified polyurethane film was 117°, and the contact angle after plasma surface treatment + layer-by-layer self-assembly was 59.7°. After one month, its contact angle was measured to be 61.2°.

Example 10

(1) Soak the polyurethane film with absolute ethanol, then rinse repeatedly with deionized water, and place it in a vacuum drying oven to dry;

(2) Place the dried polyurethane carrier in a plasma treatment device, evacuate the instrument to a vacuum of 10 Pa, inject argon plasma gas, and adjust the pressure in the reactor to 50 Pa. After stabilization, start the high-frequency power supply, the processing power is 150W, and the processing time is 15min;

(3) Put the surface-treated polyurethane film into a polydiallyldimethylammonium chloride solution with a concentration of 0.05mmol/L, and soak for 45min at an adsorption temperature of 4°C. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(4) Put the polyurethane film into a 0.01 mmol/L sodium polystyrene sulfonate solution at an adsorption temperature of 5° C. and soak for 25 min. Take out the polyurethane film, clean it with deionized water, and then dry it with cold air at 3°C;

(5) Steps (3) and (4) were repeated five times in sequence to complete the layer-by-layer self-assembly process to obtain a modified polyurethane film.

The contact angle of the unmodified polyurethane film was 117°, and the contact angle after plasma surface treatment + layer by layer self-assembly was 61.2°. After one month, its contact angle was measured to be 63.5°.

Example 11

Same as Example 1, the only difference is that the soaking time is 15min in the step (3), and the soaking time in the step (4) is 15min.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer-by-layer self-assembly, the contact angle was 50.2°. After one month, its contact angle was measured to be 52.2°.

Example 12

Same as Example 1, the only difference is that the soaking time is 50min in the step (3), and the soaking time in the step (4) is 50min.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 42.5°. After one month, measure its contact angle and be 44.7 °.

Example 13

Same as Example 1, the only difference is that the air pressure in the reactor in step (2) is 70Pa.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 48.5°. After one month, its contact angle was measured to be 50.2°.

Example 14

Same as Example 1, the only difference is that the pressure in the reactor in step (2) is 20Pa.

The contact angle of the unmodified polyurethane film was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 58.8°. After one month, its contact angle was measured to be 61.2°.

Example 15

Same as Embodiment 1, the only difference is that the processing power in step (2) is 300W.

The contact angle of the unmodified polyurethane film was 117°, and the contact angle after plasma surface treatment + layer by layer self-assembly was 68.7°. After one month, its contact angle was measured to be 69.9°.

Example 16

Same as Embodiment 1, the only difference is that the processing power in step (2) is 10W.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 62.7°. After one month, its contact angle was measured to be 64.2°.

Example 17

Same as Example 1, the only difference is that the processing time in step (2) is 10min.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer-by-layer self-assembly, the contact angle was 58.4°. After one month, its contact angle was measured to be 60.1°.

Example 18

Same as Example 1, the only difference is that the processing time in step (2) is 30min.

The contact angle of the polyurethane film before modification was 117°, and after plasma surface treatment + layer by layer self-assembly, the contact angle was 48.2°. After one month, its contact angle was measured to be 49.3°.

It should be noted that the above-mentioned embodiments are only used to explain the present invention, and do not constitute any limitation to the present invention. The invention has been described with reference to typical embodiments, but the words which have been used therein are words of description and explanation rather than words of limitation. The present invention can be modified within the scope of the claims of the present invention as prescribed, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the invention described therein refers to specific methods, materials and examples, it is not intended that the invention be limited to the specific examples disclosed therein, but rather, the invention extends to all other methods and applications having the same function.

Claims (10)

1. A method for surface hydrophilic modification of a polyurethane carrier, comprising: Step S1, subjecting the polyurethane carrier to plasma surface treatment to obtain a plasma surface-treated polyurethane carrier; Step S2, contacting the plasma-surface-treated polyurethane carrier obtained in step S1 with a polycation solution for polycation solution treatment to obtain a polycation-modified polyurethane carrier; Step S3, contacting the polycation-modified polyurethane carrier obtained in step S2 with a polyanion solution to treat the polyanion solution to obtain a polyanion-modified polyurethane carrier. 2. method according to claim 1, it is characterized in that, described method also comprises step S4: repeat the polycation solution processing of step S2 and the polyanion solution processing process 2-20 of step S3 successively, preferred 5-12 Second-rate. 3. The method according to claim 1 or 2, characterized in that, the plasma surface treatment is to place the polyurethane carrier in a plasma treatment device, and inject plasma gas for plasma surface treatment. 4. The method according to claim 3, wherein the plasma gas is selected from the plasma gas of one or more substances in air, oxygen, nitrogen, ammonia, argon, acrylic acid and allylamine . 5. The method according to claim 3 or 4, characterized in that, the air pressure of the plasma gas is 20-80Pa, preferably 50-70Pa, and/or, the time of plasma surface treatment is 10-100min, preferably 10-30min, and/or, the power of the plasma treatment device is 10-300W, preferably 50-150W. 6. according to the method described in any one in claim 1-5, it is characterized in that, described polycation solution is selected from polydiallyl dimethyl ammonium chloride solution, cationic polyacrylamide solution and chitosan One or more polycations in the solution, preferably, the concentration of the polycation solution is 0.01-0.1 mmol/L. 7. according to the method described in any one in claim 1-6, it is characterized in that, described polyanion solution is selected from one or more in polystyrene sodium sulfonate solution, sodium alginate solution and polyacrylic acid solution One, preferably, the concentration of the polyanion solution is 0.01-0.1mmol/L. 8. according to the method described in any one in claim 1-7, it is characterized in that, in step S2, the mode that polyurethane carrier contacts with polycation solution is to use polycation solution to impregnate polyurethane carrier, preferably, the time of immersion 15-60min, the impregnation temperature is 2-6°C; And/or, in step S3, the method of contacting the polyurethane carrier with the polyanion solution is to impregnate the polyurethane carrier with the polyanion solution, preferably, the impregnation time is 15-60 min, and the impregnation temperature is 2-6°C. 9. The method according to any one of claims 1-8, characterized in that, in step S2, after the polyurethane carrier is in contact with the polycation solution, the polyurethane carrier is cleaned and dried before step S3 is performed, preferably, The drying method is cold air drying, and the temperature of the cold air is preferably 1-5°C; And/or, in step S3, after the polyurethane carrier is in contact with the polyanion solution, the polyurethane carrier is cleaned and dried. Preferably, the drying method is cold air drying, and the temperature of the cold air is preferably 1-5°C. 10. The method according to any one of claims 1-9, characterized in that, the polyurethane carrier is selected from a polyurethane film and/or a porous polyurethane carrier.