CN111004508B - Hydrophilic single-layer porous membrane and preparation method and application thereof - Google Patents

Abstract

The invention discloses a hydrophilic single-layer porous membrane, a preparation method and application thereof, and belongs to the technical field of functional material preparation. In the present invention, the hydrophilic monolayer polymer porous membrane is finally prepared by preparing the casting liquid, scraping the membrane and using the phase inversion method, and by changing the initial concentration of the casting liquid, the thickness of the scraped membrane, the composition of the phase inversion solvent and the The ratio of mixed phase inversion solvent is used to control the preparation of asymmetric micro-nano pores with different pore sizes on the opposite surface of the single-layer polymer membrane, so as to realize intelligent control of different liquid permeation states. The preparation method of the hydrophilic single-layer porous membrane disclosed in the invention is simple and easy to implement, the thickness of the prepared porous membrane, the membrane porosity and the membrane pore size are easy to control, and the cost is low, environment-friendly, safe and reliable, and easy to be produced on an industrial scale. , which can be well used in the field of liquid unidirectional penetration, fast drying wound dressings or functional textiles and directional transportation.

Description

A kind of hydrophilic monolayer porous membrane and its preparation method and application

technical field

The invention relates to the technical field of preparation of functional materials, in particular to a hydrophilic single-layer porous membrane and a preparation method and application thereof, in particular to the preparation of a single-layer porous membrane with asymmetric surface pore size and the application of the porous membrane to a liquid monolayer Infiltration, fast drying wound dressings or functional textiles and directional transport.

Background technique

Directional permeation of liquids, i.e. liquids that can permeate from one surface of a membrane to another but are blocked in the reverse direction, are used in smart liquid manipulation, designing advanced liquid delivery systems, dressings for rapidly drying wounds, functional textiles, and microfluidics on a chip played an irreplaceable role. Researchers have formed porous structures with different pore sizes, opposite wettability, and multi-layer close-packed films. Due to the difference in interlayer wettability and pore size, the Laplace pressure difference drives the orientation of the liquid between the porous structures. transport, so as to achieve the performance of liquid independent one-way permeation. And by designing and constructing the hydrophilic-hydrophobic asymmetry on both sides of the membrane, the unidirectional osmotic transport of liquid can be realized.

At present, although people are accustomed to applying a combination of multilayer fabrics to achieve asymmetry in structure and wettability, and thus achieve unidirectional liquid permeation, the multilayer structure of porous materials also leads to complex preparation and regulation processes as well as in the environment. instability, easy delamination and poor mechanical properties. And for the liquid to penetrate from the hydrophobic side to the hydrophilic side, the required initial driving pressure is larger. Meanwhile, in a hydrophilic environment, it is difficult to control the direction of the liquid with hydrophilic porous materials because the liquid flow is often bidirectional. Therefore, how to design and fabricate hydrophilic monolayer porous membranes to achieve directional permeation of liquids remains a great challenge.

SUMMARY OF THE INVENTION

In view of this, in order to solve the technical problems existing in the prior art, the present invention provides a hydrophilic monolayer porous membrane and a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

A preparation method of a hydrophilic monolayer porous membrane, the method specifically comprises the following steps:

(1) Preparation of casting solution: stirring and mixing polymer particles, surfactant and solvent evenly to obtain polymer casting solution;

Wherein, the polymer particles are materials with good chemical stability and hydrophilicity, such as polysulfone, polyethersulfone, polymethyl methacrylate (PMMA) or polystyrene.

(2) Scraping film: use a scraper to scrape the polymer casting liquid prepared in step (1) on a glass plate, and control the thickness of the scraping film by adjusting the height of the scraper, so as to obtain a series of polymer membranes of different thicknesses;

(3) Preparation of hydrophilic single-layer porous membrane: the glass plate carrying the polymer membrane is immersed in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying to obtain a hydrophilic single-layer polymer porous membrane.

The invention discloses a method for phase inversion. The opposite surface of a single-layer polymer porous membrane has an asymmetric micro-nano pore size structure, and by changing the phase inversion solvent, a single-layer porous membrane with different permeation behaviors can be obtained, that is, changing the relative surface The pore size can control the permeation state of the liquid, so that the hydrophilic monolayer porous membrane prepared by the disclosure can be applied in the fields of unidirectional permeation and directional transport of liquids.

Preferably, the stirring temperature in the step (1) is 50°C to 100°C, and the stirring time is 3 to 24 hours.

Preferably, in the step (2), the thickness of the polymer film is 1 μm˜200 μm.

Further preferably, the thickness of the polymer film is 25 μm˜100 μm.

It should be noted that, in the present invention, a series of hydrophilic monolayer porous polymer membranes with different thicknesses are finally obtained through phase inversion by scraping polymer films of different thicknesses on a glass plate with a scraper, and through the penetration of water droplets on them. Different permeation properties can be obtained: permeation on one side, permeation on both sides, and impermeability on both sides (see below for specific experiments).

Preferably, the soaking time in the step (3) is 1min-2h, and the soaking temperature is 10°C-50°C.

Preferably, the cleaning time in the step (3) is 10-30 min, the drying temperature is 20°C-50°C, and the drying time is 5min-2h.

Preferably, the mass ratio of the polymer particles, the surfactant and the solvent is (1-3):(1-2):(1-6), wherein the surfactant is polyvinylpyrrolidone , cetyltrimethylammonium bromide or sodium dodecyl sulfate, and the solvent is dimethylacetamide, N,N-dimethylformamide or tetrahydrofuran.

It should be noted that the polymer particles are mixed with surfactants and solvents in different proportions to obtain polymer solutions with different initial concentrations, and then different hydrophilic monolayer porous polymer membranes are obtained. Through the research on its water droplet permeability , different permeation properties can be obtained: permeation on one side, permeation on both sides, and impermeability on both sides (see below for specific experiments).

Preferably, the phase inversion solvent is at least one of methanol, ethanol, propanol, water, toluene, acetone, and sodium chloride solution.

Further preferably, the phase inversion solvent is a mixed solvent of any of the above two solvents, wherein the volume ratio between the two solvents is (0:20)˜(20:0).

It should be noted that, by changing different phase inversion solvents and adjusting the ratio between different solvents, asymmetric micro-nano pore size can be prepared on the opposite surface of the single-layer polymer membrane (see Figure 1), and the orientation of the liquid can be realized. Intelligent control of transport (permeable on one side, permeable on both sides, or impermeable on both sides).

The present invention also provides a hydrophilic monolayer porous membrane obtained by the above preparation method, the porous membrane is a polymer porous membrane prepared from a polymer by a phase inversion method, and the porous membrane is a A single-layer membrane with a nano-pore structure, and the porous membrane is a single-layer membrane with an asymmetric micro-nano pore structure, wherein one side has a pore size of 10 μm-60 μm, the other side has a pore size of 10 nm to 800 nm, and has a porosity of 70% to 90%. .

Among them, the mechanism of the hydrophilic monolayer porous membrane prepared in the present invention can realize the directional permeation of liquid is to realize the unidirectional liquid permeation on the surface of the porous membrane through the response change of surface tension and Laplace pressure, and the specific performance is as follows :

In the present invention, the difference in pore size on both sides of the membrane leads to different Laplace pressures, and the small pore size leads to a large Laplace pressure, so that the liquid can penetrate the large pore size side of the membrane from the small pore size side, and be reversed by Block, so as to have a one-way penetration performance.

Another object of the present invention is to provide the application of the prepared hydrophilic monolayer porous membrane in unidirectional liquid permeation and directional transport.

As can be seen from the above technical solutions, a hydrophilic monolayer porous membrane disclosed in the present invention and its preparation method and application have the following excellent characteristics compared with the prior art:

First of all, the present invention provides a preparation method of a hydrophilic monolayer porous membrane. The hydrophilic monolayer polymer porous membrane is finally prepared by formulating a casting solution, scraping the membrane and using a phase inversion method in turn. The initial concentration of the film liquid, the thickness of the wiped film, the composition of the phase inversion solvent and the ratio of the mixed phase inversion solvent are used to control the preparation of asymmetric micro-nano pores on the opposite surfaces of the single-layer polymer film to realize the directional transport of the liquid. Intelligent control of transportation.

Further, the present invention provides a hydrophilic monolayer porous membrane prepared by the above preparation method and its application in liquid unidirectional permeation and directional transport. Because the porous membrane is a single-layer membrane with an asymmetric micro-nano pore structure, it can realize different permeation states of liquid without external assistance, so as to overcome the complex preparation and adjustment process of the multi-layer structure of porous materials in the prior art and the Instability in the environment, prone to delamination and poor mechanical properties.

To sum up, the preparation method of the hydrophilic monolayer porous membrane disclosed in the present invention is simple and feasible, the thickness of the prepared porous membrane, membrane porosity and membrane pore size are easy to control, and the cost is low, environment-friendly, safe and reliable. It is easy to be produced on an industrial scale, and can be well applied to the field of unidirectional liquid penetration, fast drying wound dressings or functional textiles and directional transportation to realize intelligent control of directional liquid transportation, which is innovative.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

Fig. 1 is the SEM topography of the hydrophilic polymer monolayer porous membrane with asymmetric pore size of the present invention; wherein,

Figures 1(a) and 1(e) are alcohol-converted hydrophilic polymer monolayer porous membranes, Figure 1(b) and Figure 1(f) are acetone-converted hydrophilic polymer monolayer porous membranes, Figure 1(c) ) and Figure 1(g) are toluene-converted hydrophilic polymer monolayer porous membranes, Figure 1(d) and Figure 1(h) are two solvent mixed conversion hydrophilic polymer monolayer porous membranes; and Figure 1(a) )-Fig. 1(d) are the front morphologies of the single-layer porous film, and Fig. 1(e)-Fig. 1(h) are the reverse morphologies of the single-layer porous film.

Figure 2 shows the contact angle of water on the front and back sides of the hydrophilic polymer monolayer porous membrane converted by mixing two solvents according to the present invention, wherein the droplet volume is 5 μL.

Fig. 3 is the unidirectional permeation state of the asymmetric pore size polymer monolayer membrane of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The embodiment of the present invention discloses a preparation method of a hydrophilic monolayer porous membrane. The hydrophilic monolayer porous membrane prepared by the present invention can change or control the transport direction of liquid without the assistance of external force, which overcomes the problems of the prior art. The existing defects are suitable for promotion and application.

In order to better understand the present invention, the present invention is further described in detail below by the following examples, but it should not be understood as a limitation of the present invention. For some non-essential improvements and adjustments made by those skilled in the art according to the above-mentioned content of the invention, It is also regarded as falling within the protection scope of the present invention.

A preparation method of a hydrophilic monolayer porous membrane with asymmetric pore size, the method specifically comprises the following steps:

(1) Mix the polymer, surfactant and solvent in the ratio of (1-3):(1-2):(1-6), wherein the surfactant is preferably PVP (polyvinylpyrrolidone), CTAB (hexadecane) Alkyl trimethyl ammonium bromide) or SDS (sodium dodecyl sulfate), the solvent is preferably DMAC (dimethylacetamide) or THF (tetrahydrofuran), stir at (50 ℃ ~ 100 ℃) for 3 ~ 24h, A homogeneous polymer solution was obtained.

(2) Use a scraper to scrape the film on a clean glass plate with different thicknesses (1μm to 200μm), and immediately immerse the glass sheet with the polymer film of different thickness in different phase inversion solvents. The phase inversion solvents are preferably methanol, ethanol, Propanol, water, toluene, acetone, sodium chloride solution and mixed solvents in different proportions, etc. For example, mixing toluene and water into solutions of different ratios as the phase inversion solvent, where toluene:water=(0:20)～(20:0), finally obtains a series of monolayer asymmetric pore size (one side is large, the other side is large). small) hydrophilic polymer monolayers.

(3) Ultrasonic cleaning of the hydrophilic polymer monolayer film with ethanol for 10-30 min, drying for use.

Another object of the present invention is to provide a hydrophilic monolayer porous membrane prepared by the above method, the porous membrane is a polymer porous membrane prepared from a macromolecule by a phase inversion method, and the porous membrane is It is a monolayer membrane with asymmetric micro-nano pore structure.

Another object of the present invention is to provide the application of the above-mentioned hydrophilic monolayer porous membrane in the unidirectional permeation and directional transport of liquids.

Hereinafter, the technical solutions of the present invention will be further described with reference to specific embodiments.

Example 1:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of the casting solution: the polysulfone polymer particles, PVP and DMF are stirred and mixed evenly in a ratio of 3:1:6 to obtain a polysulfone casting solution;

(2) Scraping film: using a scraper to scrape the polysulfone casting solution prepared in step (1) on a glass plate, and adjusting the height of the scraper to control the thickness of the scraped membrane to obtain a 100 μm polysulfone membrane;

(3) Preparation of hydrophilic monolayer porous membrane: immersing the polysulfone-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polysulfone porous membrane.

(4) Through the study of its water droplet permeability, the permeability performance of both sides can be obtained.

Example 2:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of casting solution: the polyethersulfone polymer particles, PVP and DMF are stirred and mixed uniformly at a ratio of 3:1:6 to obtain a polyethersulfone casting solution;

(2) Scraping film: the polyethersulfone membrane liquid prepared in step (1) is scraped on a glass plate with a scraper, and the thickness of the scraped membrane is controlled by adjusting the height of the scraper to obtain a series of polystyrene membranes with different thicknesses ;

(3) Preparation of hydrophilic monolayer porous membrane: immerse the glass plate carrying the polyethersulfone membrane in a phase inversion solvent for a predetermined time, then ultrasonically clean and dry to obtain a hydrophilic monolayer polyethersulfone porous membrane.

(4) Through the study of its water droplet permeability, different permeability properties can be obtained: two-sided permeation, one-sided permeation, and no two-sided permeation.

Example 3:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of casting liquid: the polymethyl methacrylate polymer particles, PVP and DMF are stirred and mixed uniformly at a ratio of 3:1:6 to obtain a polymethyl methacrylate casting liquid;

(2) Scraping film: use a scraper to scrape the polymethyl methacrylate casting solution prepared in step (1) on a glass plate, and adjust the height of the scraper to control the thickness of the scraped membrane to obtain a series of different thicknesses. Polyethersulfone membrane;

(3) Preparation of hydrophilic monolayer porous membrane: immerse the glass plate loaded with polymethyl methacrylate in a phase inversion solvent for a predetermined time, then ultrasonically clean and dry to obtain a hydrophilic monolayer polymethacrylate Methyl ester porous membrane.

(4) Through the study of its water droplet permeability, different permeability properties can be obtained: two-sided permeation, one-sided permeation, and no two-sided permeation.

Example 4:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of casting liquid: the polystyrene polymer particles, PVP and DMF are stirred and mixed uniformly at a ratio of 3:1:6 to obtain a polystyrene casting liquid;

(2) Scraping film: use a scraper to scrape the polystyrene casting solution prepared in step (1) on a glass plate, and adjust the height of the scraper to control the thickness of the scraped membrane to obtain a series of polystyrene with different thicknesses membrane;

(3) Preparation of a hydrophilic monolayer porous membrane: immersing a polystyrene-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polystyrene porous membrane.

(4) Through the study of its water droplet permeability, different permeability properties can be obtained: two-sided permeation, one-sided permeation, and no two-sided permeation.

Example 5:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of casting solution: The polysulfone polymer particles, SDS and DMF are stirred and mixed uniformly in a ratio of 3:1:6 to obtain a polysulfone casting solution;

(2) Scraping the film: using a scraper to scrape the polysulfone casting solution prepared in step (1) on a glass plate, and adjusting the height of the scraper to control the thickness of the scraped membrane to obtain a series of polysulfone membranes with different thicknesses;

(3) Preparation of hydrophilic monolayer porous membrane: immersing the polysulfone-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polysulfone porous membrane.

(4) Through the study of its water droplet permeability, the permeability performance of both sides can be obtained.

Example 6:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of the casting solution: the polysulfone polymer particles, CTAB and DMF are stirred and mixed uniformly in a ratio of 3:1:6 to obtain a polysulfone casting solution;

(2) Scraping the film: using a scraper to scrape the polysulfone casting solution prepared in step (1) on a glass plate, and adjusting the height of the scraper to control the thickness of the scraped membrane to obtain a series of polysulfone membranes with different thicknesses;

(3) Preparation of hydrophilic monolayer porous membrane: immersing the polysulfone-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polysulfone porous membrane.

(4) Through the study of its water droplet permeability, the permeability performance of both sides can be obtained.

Example 7:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of the casting solution: the polysulfone polymer particles, sodium lauryl sulfate and DMF are stirred and mixed uniformly in a ratio of 3:1:6 to obtain a polysulfone casting solution;

(2) Scraping the film: using a scraper to scrape the polysulfone casting solution prepared in step (1) on a glass plate, and adjusting the height of the scraper to control the thickness of the scraped membrane to obtain a series of polysulfone membranes with different thicknesses;

(3) Preparation of hydrophilic monolayer porous membrane: immersing the polysulfone-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polysulfone porous membrane.

(4) Through the study of its water droplet permeability, the permeability performance of both sides can be obtained.

Example 8:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of a casting solution: the polysulfone polymer particles, sodium dodecyl sulfate and tetrahydrofuran are stirred and mixed uniformly in a ratio of 3:1:6 to obtain a polysulfone casting solution;

(2) Scraping the film: using a scraper to scrape the polysulfone casting solution prepared in step (1) on a glass plate, and adjusting the height of the scraper to control the thickness of the scraped membrane to obtain a series of polysulfone membranes with different thicknesses;

(3) Preparation of hydrophilic monolayer porous membrane: immersing the polysulfone-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polysulfone porous membrane.

(4) Through the study of its water droplet permeability, the permeability performance of both sides can be obtained.

Example 9:

Preparation method and permeability of a hydrophilic monolayer porous membrane

(1) Preparation of casting solution: the polysulfone polymer particles, sodium dodecyl sulfate and tetrahydrofuran are stirred and mixed uniformly at a ratio of 1:1:1 to obtain a polysulfone casting solution;

(2) Scraping the film: using a scraper to scrape the polysulfone casting solution prepared in step (1) on a glass plate, and adjusting the height of the scraper to control the thickness of the scraped membrane to obtain a series of polysulfone membranes with different thicknesses;

(3) Preparation of hydrophilic monolayer porous membrane: immersing the polysulfone-loaded glass plate in a phase inversion solvent for a predetermined time, followed by ultrasonic cleaning and drying, to obtain a hydrophilic monolayer polysulfone porous membrane.

(4) Through the study of its water droplet permeability, the permeability performance of both sides can be obtained.

The inventors also conducted the following experiments to further illustrate the technical effects achieved by the technical solutions disclosed in the present invention.

Experiment 1: Study on the preparation of polymer membranes with different pore sizes and their permeability by changing different phase inversion solvents

Polymer membranes with different pore sizes were prepared by changing different phase inversion solvents. The preferred phase inversion solvents were methanol, ethanol, propanol, water, toluene, acetone, and sodium chloride solution. A series of monolayers with different relative surface pore sizes were obtained. Water PES membranes (Figures 1, 2).

Through the study of its water droplet permeability, it can be found that by changing the phase inversion solvent, different permeability properties can be obtained: permeable on both sides and impermeable on both sides.

Experiment 2: Preparation of polymer membranes with different pore sizes and their permeability by changing the ratio of mixed-phase inversion solvents

Mixing different phase inversion solvents in different proportions and adjusting different mixing ratios (one solvent: another solvent=(0:20)～(20:0)) can obtain a series of single-layer polymer membranes with different relative surface pore sizes (figure 1).

By studying the permeability of its water droplets, different permeation properties can be obtained: two-sided permeation, one-sided permeation (Fig. 3), and no two-sided permeation.

Experiment 3: Preparation of polymer membranes with different pore sizes and their permeability by changing the thickness of the scraped membrane

Use a scraper to scrape out polymer films of different thicknesses on the glass plate, wherein the thickness is preferably 25 μm to 100 μm, to obtain a series of single-layer polymer films of different thicknesses and different pore sizes.

Through the study of its water droplet permeability, different permeation properties can be obtained: two-sided permeation, one-sided permeation, and no two-sided permeation.

Experiment 4: Preparation of polymer membranes with different pore sizes and their permeability by changing different initial concentrations of membrane casting solutions

The polymer, surfactant and solvent are mixed in different ratios, wherein the ratio is preferably (1-3):(1-2):(1-6) to obtain polymer solutions with different initial concentrations.

Through the study of its water droplet permeability, different permeability properties can be obtained: two-sided permeation, one-sided permeation, and no two-sided permeation.

Experiment 5: Study on the preparation of polymer membranes with different pore sizes and their permeability by changing the time and temperature of different phase transitions

Polymer membranes with different pore sizes were prepared by changing the immersion time and temperature of the phase inversion solvent for the glass plate loaded with the polymer casting solution. At 50°C, a series of monolayer hydrophilic polymer membranes with different relative surface pore diameters can be obtained.

Through the study of its water droplet permeability, it can be found that by changing the phase inversion solvent, different permeability properties can be obtained: permeable on both sides and impermeable on both sides.

Experiment 6: Change the drying temperature of different polymer membranes to prepare polymer membranes with different relative surface pore sizes

By changing the drying temperature of the polymer membrane, polymer membranes with different relative surface pore diameters were prepared. The soaking time was preferably 1min-2h, and the soaking temperature was 10℃-50℃. A series of monolayers with different relative surface pore diameters could be obtained. Water polymer film. If the temperature is too high, the polymer membrane will melt, and if the temperature is too low, the membrane will become brittle and affect its permeability.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A method for preparing a hydrophilic single-layer porous membrane, which is characterized by comprising the following steps:

(1) preparing a casting solution: stirring and mixing the polymer particles, the surfactant and the solvent uniformly to obtain a polymer membrane casting solution;

(2) film scraping: coating the polymer membrane casting solution prepared in the step (1) on a glass plate by adopting a scraper, and controlling the thickness of the scraped membrane by adjusting the height of the scraper so as to obtain a series of polymer membranes with different thicknesses;

(3) preparing a hydrophilic single-layer porous membrane: immersing the glass plate loaded with the polymer film casting solution into a phase inversion solvent for a preset time, performing phase inversion separation to form a film, and then ultrasonically cleaning and drying the film to obtain a hydrophilic single-layer polymer porous film;

wherein in the step (2), the thickness of the polymer film is 1-200 μm;

the mass ratio of the polymer particles, the surfactant and the solvent is (1-3): 1-2): 1-6, the surfactant is polyvinylpyrrolidone, cetyl trimethyl ammonium bromide or sodium dodecyl sulfate, the solvent is dimethylacetamide or tetrahydrofuran, and the polymer particles are polysulfone polymer particles, polyether sulfone polymer particles, polymethyl methacrylate polymer particles or polystyrene polymer particles;

the phase inversion solvent is a solvent formed by mixing any two of methanol, ethanol, propanol, water, toluene and acetone according to a volume ratio of (0:20) - (20: 0);

and the porous membrane is a polymer porous membrane prepared by a macromolecule through a phase inversion method, and is a single-layer membrane with an asymmetric micro-nano pore structure, wherein the pore diameter of one surface is 10-60 mu m, the pore diameter of the other surface is 10-800 nm, and the porosity is 70-90%.

2. The method for preparing a hydrophilic single-layer porous membrane according to claim 1, wherein the stirring temperature in the step (1) is 50 ℃ to 100 ℃, and the stirring time is 3 to 24 hours.

3. The method for preparing a hydrophilic single-layer porous membrane according to claim 1, wherein the soaking time in the step (3) is 1min to 2h, and the soaking temperature is 10 ℃ to 50 ℃.

4. The method for preparing a hydrophilic single-layer porous membrane according to claim 3, wherein the cleaning time in the step (3) is 10-30 min, the drying temperature is 20-50 ℃, and the drying time is 5min-2 h.

5. A hydrophilic single-layer porous membrane obtained by the production method according to any one of claims 1 to 4.

6. The use of the hydrophilic single-layer porous membrane according to claim 5, wherein the porous membrane is used in the unidirectional liquid permeation, the dressing or functional textile for fast drying of wounds and the directional liquid transportation.

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