A high-efficiency one-way water guide, quick-drying single-layer nanofiber membrane and a preparation method thereof

Abstract

The application discloses a kind of high-efficiency one-way water guide, quick-drying single-layer nanofiber membrane and preparation method thereof, belong to textile material technical field.The preparation of single-layer nanofiber membrane of the application includes: single-layer nanofiber membrane preparation, electrospinning parameter: voltage is 10~35kV, perfusion speed is by 0ml h ‑1 Linear increase to 1~5ml h ‑1 , the increment of perfusion rate is 0.1~10 μL s ‑1 Per second, receiving distance is 10-30cm, spinning ambient temperature is 25-50 DEG C;Humidity is 20-70%;Then single-layer nanofiber membrane is partially hydrophobic modification and patterned hydrophilic modification in form of hollow template, namely obtained.The single-layer nanofiber membrane can accelerate the transmission efficiency of moisture in water guide channel, the separation rate of liquid drop form in the form of separating from the surface of fabric is much greater than the moisture evaporation rate of ordinary Janus fabric, greatly improve the overall comfort of human microenvironment.

Description

TECHNICAL FIELD

[0001] The application relates to a high-efficiency one-way water guide and quick-drying single-layer nanofiber membrane and a preparation method thereof, and belongs to the technical field of textile materials. BACKGROUND

[0002] Existing outdoor high-comfort textiles mainly include commercial polyester fabrics Dry-FIT and Cool-max. The two utilize the super-high capillary force between profiled fibers to enhance sweat and evaporation efficiency, which can significantly accelerate the sweat discharge rate. However, the water transmission process is bidirectional, and cannot prevent the invasion of external rainwater.

[0003] In recent years, textiles with one-way water transmission characteristics have attracted much attention. A four-layer composite nanofiber membrane prepared from different proportions of polyurethane and boron nitride nanosheets is reported in the literature Advanced Functional Materials, 2021, Vol. 31, No. 14, 2008705. The membrane has a hierarchical porous structure gradually decreasing from bottom to top, and the one-way water transmission index is relatively low, being 1072%. ACS Applied Materials & Interfaces, 2022, Vol. 14, No. 16, pp. 18944-18953, reports a three-layer composite one-way wet guide fabric with gradient wettability, and the one-way transport index is 1522%. Such fabrics have asymmetric pore sizes or asymmetric wettability in the thickness direction, which can make liquid spontaneously one-way transport from the hydrophobic side to the hydrophilic side or directional penetration of the fabric along the decreasing pore size direction, and prevent water transmission in the opposite direction. Such one-way liquid flow textiles play a key role in maintaining human physiological and psychological comfort as they can effectively manage skin dryness and microclimate temperature and humidity. However, the preparation steps are complicated, the hydrophilic side is easy to be saturated with moisture, and the water on the surface of the fabric has a low rate of separation, which makes people feel hot and uncomfortable, and even causes stress reaction. SUMMARY

[0004] [TECHNICAL PROBLEM]

[0005] In existing one-way wet guide fabrics, most of them are multi-layer composite fabrics. Such fabrics have complicated preparation steps and are easy to peel off. In high-sweating or high-humidity environments, the hydrophilic side of the fabric is easy to be saturated with moisture, and the rate of water vapor form the water on the surface of the fabric is much smaller than the sweat rate of the human body under conditions such as intense exercise (1.5 L h -1 ), which cannot meet the demand of the human body for high water guide and quick-drying performance of textile fabrics.

[0006] To this end, the application innovatively uses a one-step electrospinning technology to prepare a continuous gradient hierarchical porous single-layer nanofiber membrane, and combines it with asymmetric gradient wettability, both of which work together to achieve efficient one-way water guiding and quick-drying performance of the material. The single-layer nanofiber membrane is different from ordinary one-way wet fabric. The nanofiber membrane can make water gather in the form of droplets on one side of the membrane and then separate from the surface of the fabric. The water separation rate is much greater than the evaporation rate of water on the surface of ordinary Janus fabric after spreading (0.735 g h -1 ), and also much greater than the maximum perspiration rate of the human body in high temperature, high humidity and high intensity exercise scenarios (1.5 x 10 3 g / (m 2 ·h)), greatly improving the overall comfort of the human microenvironment.

[0007] [Technical scheme]

[0008] In order to achieve the above purpose, the application provides the following technical scheme:

[0009] The application provides a single-layer nanofiber membrane with efficient one-way water guiding and quick-drying and a preparation method thereof. The infusion speed of the nanofiber membrane in the spinning process is controlled in real time by a microcomputer, so that it increases linearly within a set range, so that the prepared single-layer nanofiber membrane has a continuous gradient hierarchical porous structure. The hierarchical porous structure makes the nanofiber membrane have a gradually enhanced differential capillary effect. Under the action of capillary driving force, liquid tends to transport water in the direction of smaller pore size and hinder its reverse transport. Subsequently, the continuous gradient hierarchical porous nanofiber membrane is hydrophobically modified, and the local part is hydrophilically modified by using a patterned template, so that the local part has a wettability gradient water guiding channel along the thickness direction. Due to the synergistic effect of the pore size difference and the wettability difference in the channel, the water transport efficiency in the water guiding channel can be accelerated, and water droplets are formed on the surface of the membrane. With body swing, the droplets can be dripped. The separation rate of the droplets from the surface of the fabric is much greater than the evaporation rate of water on the surface of ordinary Janus fabric.

[0010] The specific technical scheme is as follows:

[0011] The application provides a preparation method of a single-layer nanofiber membrane with efficient one-way water guiding and quick-drying, which comprises the following steps:

[0012] (1) Prepare a polymer spinning solution, and prepare a continuous gradient hierarchical porous single-layer nanofiber membrane by using an electrospinning technology: electrospinning parameters: voltage is 10-35 kV, infusion speed is linearly increased from 0 ml h -1 to 1-5 ml h -1 , and the increment of infusion rate per second is 0.1-10 μL s -1, the receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃; the humidity is 20-70%;

[0013] (2) The single-layer nanofiber membrane with continuous gradient hierarchical porous obtained in step (1) is placed in a hydrophobic modifier for local hydrophobic modification.

[0014] (3) The patterned hollow template is taken and placed on one side of the single-layer nanofiber membrane after hydrophobic modification in step (2) for hydrophilic modification, and a single-layer nanofiber membrane with efficient unidirectional water guide and quick drying is obtained.

[0015] In an embodiment, the concentration of the polymer spinning solution in step (1) is 5-20 wt%.

[0016] In an embodiment, the polymer used in the polymer spinning solution in step (1) is one or more of polycaprolactone, polypropylene, polyacrylonitrile, polyvinyl alcohol, polyethylene glycol, and sodium polyacrylate.

[0017] In an embodiment, the solvent used in the polymer spinning solution in step (1) is one or more of water, toluene, xylene, acetone, cyclohexanone, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide.

[0018] In an embodiment, the electrospinning parameter in step (1) is: the voltage is 10-35 kV, the infusion speed is increased linearly from 0 ml h -1 to 1-3 ml h -1 , the infusion rate is increased by 0.1-5 μL s -1 , the receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃; the humidity is 20-70%.

[0019] In an embodiment, the electrospinning parameter in step (1) is: the voltage is 10-35 kV, the infusion speed is increased linearly from 0 ml h -1 to 2 ml h -1 , the infusion rate is increased by 1-1.5 μL s -1 , the receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃; the humidity is 20-70%.

[0020] In an embodiment, the electrospinning parameter in step (1) is: the voltage is 10-35 kV, the infusion speed is increased linearly from 0 ml h -1 to 4 ml h -1 , the infusion rate is increased by 1-1.5 μL s -1 , the receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃; the humidity is 20-70%.

[0021] In one embodiment, the electrospinning parameters in step (1) are: voltage of 15 kV, infusion speed of 0 ml h -1 linearly increased to 2 ml h -1 , the infusion rate of each second increment is 1.2 μL s -1 , the receiving distance is 15 cm, the spinning ambient temperature is 30℃, and the humidity is 50%.

[0022] In one embodiment, the single-layer nanofiber membrane with continuously graded hierarchical porosity in step (1) has a pore size ranging from 50 nm to 50 μm.

[0023] In one embodiment, the hydrophobic modifier in step (2) is any one of polyurethane, silane coupling agent, or commercial hydrophobic modifier.

[0024] In one embodiment, the polyurethane includes one or more of organosilicon modified polyurethane, fluorinated polyurethane, and nanomaterial modified polyurethane.

[0025] In one embodiment, the silane coupling agent includes one or more of vinyl silane, amino silane, epoxy silane, mercapto silane, and methacryloyloxy silane.

[0026] In one embodiment, the hydrophobic modification in step (2) is to immerse the continuously graded hierarchical porous nanofiber membrane in the hydrophobic modifier, and dry it for later use.

[0027] In one embodiment, the patterned hollow template in step (3) has a hollow pore size of 0.5-5 mm and a hollow lattice pitch of 5-20 mm.

[0028] In one embodiment, the patterned hollow template in step (3) has a hollow pore size of 1-3 mm and a hollow lattice pitch of 7-9 mm.

[0029] In one embodiment, the patterned hollow cellulose paper template in step (3) is any one of punchable cellulose paper, adhesive tape, tin paper, and plastic plate.

[0030] In one embodiment, the local hydrophilic modification in step (3) is any one of plasma treatment and light excitation polymerization.

[0031] In one embodiment, the plasma treatment is to place the sample to be treated in a plasma treatment machine, set the cleaning time to 10-600 s, the air flow rate to 100-200 ml / min, and the power to 40-300 W.

[0032] In an embodiment, the photo-irradiation polymerization method is to immerse the sample to be treated in a mixed solution of a hydrophilic modifier and a photoinitiator, the concentration of the hydrophilic modifier is 5-50wt%, the mass ratio of the hydrophilic modifier to the photoinitiator is 10:1-1:1, then place it under a light source corresponding to the photoinitiator, the wavelength of the light source is 250-420nm, the irradiation time is 30-300s, and then clean and dry after irradiation.

[0033] In an embodiment, the hydrophilic modifier is an oligomer, and the concentration of the oligomer is 10-60wt%, wherein the oligomer is one or more of hydroxyethyl methacrylate, polyethylene glycol bisacrylate, and acrylate.

[0034] In an embodiment, the photoinitiator is one or more of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, 4,4-dimethylphenyl bis(4-methylphenyl)carbonium bromide, diphenylstilbene benzidine, and benzophenone.

[0035] The application also provides a high-efficiency one-way water-conducting and quick-drying single-layer nanofiber membrane prepared by the above method.

[0036] In an embodiment, the high-efficiency one-way water-conducting and quick-drying single-layer nanofiber membrane has a water contact angle of 0-40° at the exposed part, a water contact angle of 100-130° at the covered part, a water contact angle of 110-140° at the bottom of the exposed part, and a water contact angle of 130-150° at the bottom of the covered part.

[0037] In an embodiment, the high-efficiency one-way water-conducting and quick-drying single-layer nanofiber membrane has a one-way water-conducting rate of (1.5-2.5)×10 5 g / (m 2 ·h). 5 g / (m 2 ·h).

[0038] The application also provides the application of the above high-efficiency one-way water-conducting and quick-drying single-layer nanofiber membrane in functional clothing, medical health, filtration and separation, and flow control.

[0039] Beneficial effects:

[0040] (1) The application adopts microcomputer control, so that the perfusion speed of the nanofiber membrane in the spinning process shows a linear increasing trend within the set range, so that the prepared single-layer nanofiber membrane has a continuous and gradually changing hierarchical porous structure, the hierarchical porous structure makes the nanofiber membrane have a gradually enhanced differential capillary effect, under the action of the capillary driving force, the liquid tends to transport water in the direction of smaller pore size and hinder the reverse transport.

[0041] (2) The asymmetric gradual wetting and the asymmetric pore size are combined in the application, and the two synergistically accelerate the unidirectional water transmission rate, greatly improving the transmission efficiency of the micro droplets. (The water contact angle of the exposed part of the single-layer nanofiber membrane is 0-40°, the water contact angle of the covered part is 100-130°, the water contact angle of the bottom of the exposed part is 110-140°, and the water contact angle of the bottom of the covered part is 130-150°; the unidirectional water transmission rate of the membrane is 1.5-2.5*10 5 g / (m 2 ·h).

[0042] (3) The single-layer nanofiber membrane prepared by the application has high unidirectional water transmission and quick drying, so that the water in the water transmission channel is continuously transmitted to the surface layer of the nanofiber membrane and gathered into droplets, which can slide off with the swing of the arm during wearing, and the form of water separation from the surface of the fabric is water droplets, and the water separation rate is (1.5-2.5)*10 5 g / (m 2 ·h), which is much higher than the water separation rate of ordinary Janus fabric surface in the form of steam (0.735g h -1 ). BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 FIG. 1 is a structural schematic diagram of the high-efficiency unidirectional moisture transmission nanofiber membrane of the application;

[0044] Figure 2 FIG. 3 is a bottom layer SEM schematic diagram of the high-efficiency unidirectional water transmission and quick drying single-layer nanofiber membrane in Example 1;

[0045] Figure 3 FIG. 4 is a top layer SEM schematic diagram of the high-efficiency unidirectional water transmission and quick drying single-layer nanofiber membrane in Example 1. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the application. The following specific embodiments further describe the application.

[0047] The test method involved in the application is as follows:

[0048] 1. Water contact angle and water rolling angle

[0049] The wettability of the sample is characterized by using a water contact angle measuring instrument.

[0050] 2. Water transmission rate

[0051] The maximum water transport rate of the test fabric is tested by setting the propelling speed of the propeller.

[0052] The raw material source involved in the present application is as follows:

[0053] The commercial silane coupling agent is DASU NANO / DASU, model S500, produced by Shanghai Huaxia Jiahe New Material Technology Co., Ltd.

[0054] Example 1

[0055] A preparation method of a single-layer nanofiber membrane with efficient one-way water guiding and quick drying, specifically comprising the following steps:

[0056] (1) Polyacrylonitrile (PAN) powder is dried in a vacuum oven at 60°C for 20h, and then an appropriate amount of PAN powder is dissolved in N,N-dimethylformamide, heated and stirred in a water bath at a temperature of 60°C for 12h, to prepare a uniform electrospinning solution with a concentration of 14wt%; the electrospinning parameters are as follows: voltage is 15kV; the infusion speed is controlled by a microcomputer in real time, and the infusion speed is set to increase from 0ml h -1 to 2ml h -1 at an increment of 1μL s -1 per second, the receiving distance is 15cm; the spinning environment temperature is controlled at 30°C and the humidity is 50%; a hierarchical porous PAN single-layer nanofiber membrane is obtained; the water contact angle of the fiber membrane is 60°;

[0057] (2) The hierarchical porous PAN nanofiber membrane is repeatedly dipped and rolled 3 times by using a commercial silane coupling agent S500, the dipping pressure is 1Mpa, and then it is transferred to a 60°C oven, and dried for 4h, to obtain a hierarchical porous PAN nanofiber membrane modified by hydrophobicity;

[0058] (3) A cellulose paper template with a patterned template with a hollow aperture of 1mm and a hollow dot array spacing of 9mm is placed on one side of the hierarchical porous PAN nanofiber membrane modified by hydrophobicity, and the patterned template side is subjected to one-side hydrophilic modification by using a plasma treatment machine, the washing time is set to 90s, the air flow rate is 170ml / min, and the power is 100W; a single-layer nanofiber membrane with efficient one-way water guiding and quick drying is obtained.

[0059] Example 2

[0060] A preparation method of a single-layer nanofiber membrane with efficient one-way water guiding and quick drying, specifically comprising the following steps:

[0061] (1) polypropylene (PP) powder was dried in a vacuum oven at 60°C for 12h, then an appropriate amount of PP powder was dissolved in a toluene solution, heated and stirred in an oil bath at a temperature of 110°C for 6h, and a uniform electrospinning solution with a concentration of 12wt% was prepared. The electrospinning parameters were as follows: the voltage was 25kV; the infusion speed was controlled by a microcomputer in real time, and the infusion speed was set to increase linearly from 0ml h -1 to 4ml h -1 at an increment of 1.5μL s -1 per second; the receiving distance was 20cm; the spinning environment temperature was controlled at 40°C; the humidity was 60%; a hierarchical porous PP single-layer nanofiber membrane was obtained, and the water contact angle of the fiber membrane was 80°;

[0062] (2) The hierarchical porous PP nanofiber membrane was repeatedly padded 3 times with a commercial silane coupling agent M190, the padding pressure was 1Mpa, and then it was transferred to a 60°C oven, and dried for 4h, to obtain a hydrophobically modified hierarchical porous PP nanofiber membrane;

[0063] (3) Polyethylene glycol diacrylate was used as a hydrophilic modifier, and was mixed with 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone at a ratio of 10:1 to prepare a mixed aqueous solution with a concentration of 20wt%. The hydrophobically modified hierarchical porous PP nanofiber membrane was immersed in the mixed solution, and after taking it out, a patterned hollow tin paper template with a pore size of 1.5mm and a hollow dot array spacing of 7mm was covered on one side of the membrane. The membrane was subjected to photopolymerization under ultraviolet light with a wavelength of 365nm for 120s, washed 3 times, and dried in a 60°C oven, to obtain a single-layer nanofiber membrane with efficient unidirectional water guiding and quick drying.

[0064] Example 3

[0065] A method for preparing a single-layer nanofiber membrane with efficient unidirectional water guiding and quick drying, specifically comprising the following steps:

[0066] (1) polyacrylonitrile (PAN) powder was dried in a vacuum oven at 60°C for 20h, then an appropriate amount of PAN powder was dissolved in N,N-dimethylformamide, heated and stirred in a water bath at a temperature of 60°C for 12h, and a uniform electrospinning solution with a concentration of 14wt% was prepared. The electrospinning parameters were as follows: the voltage was 15kV; the infusion speed was controlled by a microcomputer in real time, and the infusion speed was set to increase linearly from 0ml h -1 to 2ml h -1 at an increment of 1μL s -1 per second; the receiving distance was 15cm; the spinning environment temperature was controlled at 30°C, and the humidity was 50%; a hierarchical porous PAN single-layer nanofiber membrane was obtained; and the water contact angle of the fiber membrane was 60°;

[0067] (2) The above hierarchical porous PAN nanofiber membrane is repeatedly immersed and rolled 3 times with a commercial silane coupling agent S500 at a rolling pressure of 1 MPa, and then transferred to a 60°C oven, and dried for 4 h to obtain a hydrophobically modified hierarchical porous PAN nanofiber membrane;

[0068] (3) A cellulose paper template with a hollow aperture of 2 mm and a hollow dot array spacing of 8 mm is placed on one side of the hydrophobically modified hierarchical porous PAN nanofiber membrane, and the side of the patterned template is subjected to one-sided hydrophilic modification using a plasma treatment machine, with a cleaning time of 90 s, an air flow rate of 170 ml / min, and a power of 100 W. A single-layer nanofiber membrane with efficient one-way water guiding and quick drying is obtained.

[0069] Example 4

[0070] A method for preparing a single-layer nanofiber membrane with efficient one-way water guiding and quick drying, specifically comprising the following steps:

[0071] (1) Polyacrylonitrile (PAN) powder is dried in a 60°C vacuum oven for 20 h, and then an appropriate amount of PAN powder is dissolved in N,N-dimethylformamide, heated and stirred in a 60°C water bath for 12 h to prepare a uniform electrospinning solution with a concentration of 14 wt%; the electrospinning parameters are as follows: voltage 15 kV; the infusion speed is controlled by a microcomputer in real time, and the infusion speed is set to increase linearly from 0 ml / h -1 to 2 ml / h -1 at an increment of 1 μL / s -1 , and the receiving distance is 15 cm; the spinning environment temperature is controlled at 30°C and the humidity is 50%; a hierarchical porous PAN single-layer nanofiber membrane is obtained; the water contact angle of the fiber membrane is 60°;

[0072] (2) The above hierarchical porous PAN nanofiber membrane is repeatedly immersed and rolled 3 times with a commercial silane coupling agent S500 at a rolling pressure of 1 MPa, and then transferred to a 60°C oven, and dried for 4 h to obtain a hydrophobically modified hierarchical porous PAN nanofiber membrane;

[0073] (3) A cellulose paper template with a hollow aperture of 3 mm and a hollow dot array spacing of 7 mm is placed on one side of the hydrophobically modified hierarchical porous PAN nanofiber membrane, and the side of the patterned template is subjected to one-sided hydrophilic modification using a plasma treatment machine, with a cleaning time of 90 s, an air flow rate of 170 ml / min, and a power of 100 W. A single-layer nanofiber membrane with efficient one-way water guiding and quick drying is obtained.

[0074] Example 5

[0075] A preparation method of a single-layer nanofiber membrane with efficient one-way water guide and quick drying, specifically comprising the following steps:

[0076] (1) Polyacrylonitrile (PAN) powder is dried in a vacuum oven at 60°C for 20h, and then an appropriate amount of PAN powder is dissolved in N,N-dimethylformamide, heated and stirred in a water bath at a temperature of 60°C for 12h to prepare a uniform electrospinning solution with a concentration of 14wt%; the electrospinning parameters are as follows: the voltage is 15kV; the infusion speed is controlled by a microcomputer in real time, and the infusion speed is set to increase linearly from 0ml h -1 to 2ml h -1 , the infusion rate increases by 1.2μL s -1 per second, the receiving distance is 15cm; the spinning environment temperature is controlled at 30°C, and the humidity is 50%; a graded porous PAN single-layer nanofiber membrane is obtained; the water contact angle of the fiber membrane is 60°;

[0077] (2) The graded porous PAN nanofiber membrane is repeatedly padded with a commercial silane coupling agent S500 for 3 times, the padding pressure is 1Mpa, and then it is transferred to a 60°C oven for drying for 4h, thereby obtaining a hydrophobically modified graded porous PAN nanofiber membrane;

[0078] (3) A cellulose paper template with a patterned template aperture of 1mm and a patterned template lattice spacing of 9mm is placed on one side of the hydrophobically modified graded porous PAN nanofiber membrane, and the patterned template side is subjected to one-side hydrophilic modification by using a plasma treatment machine, the washing time is set to 90s, the air flow rate is 170ml / min, and the power is 100W; a single-layer nanofiber membrane with efficient one-way water guide and quick drying is obtained.

[0079] Example 6

[0080] A preparation method of a single-layer nanofiber membrane with efficient one-way water guide and quick drying, specifically comprising the following steps:

[0081] (1) Polyacrylonitrile (PAN) powder is dried in a vacuum oven at 60°C for 20h, and then an appropriate amount of PAN powder is dissolved in N,N-dimethylformamide, heated and stirred in a water bath at a temperature of 60°C for 12h to prepare a uniform electrospinning solution with a concentration of 14wt%; the electrospinning parameters are as follows: the voltage is 15kV; the infusion speed is controlled by a microcomputer in real time, and the infusion speed is set to increase linearly from 0ml h -1 to 3ml h -1 , the infusion rate increases by 1μL s -1 per second, the receiving distance is 15cm; the spinning environment temperature is controlled at 30°C, and the humidity is 50%; a graded porous PAN single-layer nanofiber membrane is obtained; the water contact angle of the fiber membrane is 60°;

[0082] (2) Adopting commercial silane coupling agent S500 to repeatedly dip the above hierarchical porous PAN nanofiber membrane for 3 times, the dip pressure is 1 Mpa, then transfer to 60℃ oven, drying time is 4h, the hierarchical porous PAN nanofiber membrane after hydrophobic modification is obtained;

[0083] (3) Take the cellulose paper template with hollow aperture of 1mm and hollow lattice pitch of 9mm, place it on one side of the hierarchical porous PAN nanofiber membrane after hydrophobic modification, use plasma treatment machine to perform single-side hydrophilic modification on one side of the patterned template, set the cleaning time to 90s, air flow rate to 170ml / min, and power to 100W; obtain a single-layer nanofiber membrane with efficient one-way water guide and quick drying.

[0084] Comparative Example 1

[0085] A method for preparing a single-layer nanofiber membrane with efficient one-way water guide and quick drying, specifically comprising the following steps:

[0086] (1) Dry polyacrylonitrile (PAN) powder in a 60℃ vacuum oven for 20h, then weigh an appropriate amount of PAN powder, dissolve it in N,N-dimethylformamide, heat and stir in a 60℃ water bath for 12h, and prepare a uniform electrospinning solution with a concentration of 14wt%; the electrospinning parameters are as follows: voltage is 15kV; the filling speed is manually set to 0.5ml h -1 , 1ml h -1 , 2ml h -1 , increase it from 0.5ml h -1 to 2ml h -1 in three stages, keep the total spinning time consistent, and the receiving distance is 15cm; control the spinning environment temperature to be 30℃ and the humidity to be 50%; obtain a hierarchical porous PAN single-layer nanofiber membrane; the water contact angle of the fiber membrane is 60°;

[0087] (2) Adopting commercial silane coupling agent S500 to repeatedly dip the above hierarchical porous PAN nanofiber membrane for 3 times, the dip pressure is 1 Mpa, then transfer to 60℃ oven, drying time is 4h, the hierarchical porous PAN nanofiber membrane after hydrophobic modification is obtained;

[0088] (3) Take the cellulose paper template with hollow aperture of 1mm and hollow lattice pitch of 9mm, place it on one side of the hierarchical porous PAN nanofiber membrane after hydrophobic modification, use plasma treatment machine to perform single-side hydrophilic modification on one side of the patterned template, set the cleaning time to 90s, air flow rate to 170ml / min, and power to 100W; obtain a single-layer nanofiber membrane with efficient one-way water guide and quick drying.

[0089] Comparative Example 2

[0090] A preparation method of a single-layer nanofiber membrane with efficient one-way water guide and quick drying, specifically comprising the following steps:

[0091] (1) Polyacrylonitrile (PAN) powder is dried in a vacuum oven at 60℃ for 20h, and then an appropriate amount of the PAN powder is dissolved in N,N-dimethylformamide, heated and stirred in a water bath at a temperature of 60℃ for 12h to prepare a uniform electrospinning solution with a concentration of 14wt%; the electrospinning parameters are as follows: the voltage is 15kV; the infusion speed is set to increase from 0ml h -1 to 2ml h -1 at an increment of 1μL s -1 per second, the receiving distance is 15cm; the spinning environment temperature is controlled at 30℃ and the humidity is 50%; a graded porous PAN single-layer nanofiber membrane is obtained; the water contact angle of the fiber membrane is 60°;

[0092] (2) The graded porous PAN nanofiber membrane is repeatedly padded with a commercial silane coupling agent S500 for 3 times, the padding pressure is 1Mpa, and then it is transferred to a 60℃ oven for drying for 4h to obtain a hydrophobically modified graded porous PAN nanofiber membrane;

[0093] (3) The one side of the membrane is directly subjected to one-side hydrophilic modification by using a plasma treatment machine, the washing time is set to 90s, the air flow rate is 170ml / min, and the power is 100W; a single-layer nanofiber membrane with one-way water guide and quick drying function is obtained.

[0094] Result analysis

[0095] The single-layer nanofiber membranes prepared in Examples 1-6 and Comparative Examples 1-2 are subjected to performance test indexes, and the results are shown in Table 1:

[0096] Table 1: Water guide performance test indexes of nanofiber membranes of examples and comparative examples

[0097]

[0098] Note: The exposed place refers to the exposed place of the fabric after the patterned hollow template is covered on the top layer of the fabric during hydrophilic modification; the covered place refers to the part of the fabric covered by the patterned hollow template; the bottom of the exposed place refers to the bottom side of the fabric corresponding to the exposed place of the patterned hollow template; the bottom of the covered place refers to the bottom side of the fabric corresponding to the part of the fabric covered by the patterned hollow template.

[0099] As shown in Table 1, the single-layer nanofiber membrane obtained by using the technical solution of the present application has a large water guide rate, such as Examples 1-6, the water guide rate reaches 1.5-2.5×10 5g / (m 2 • h); compared with Comparative Examples 1 and 2, the maximum water permeation rate is increased by one order of magnitude; and from Examples 1, 3 and 4, it can be seen that the change of the patterned template parameters also affects the maximum water permeation rate of the single-layer fiber membrane, and because the hollow point diameter of Examples 3 and 4 is larger, the hydrophilic point is larger, which causes the water droplets to easily reverse osmosis after gathering on the top after forming the water permeation channel, so the maximum water permeation rate decreases; the larger hydrophilic point also has a greater adhesion to water, so the rolling angle becomes larger.

[0100] Example 5 has the same perfusion speed interval as Example 1, but the increment of the perfusion rate per second is increased from 1 μL s -1 to 1.2 μL s -1 , the change speed becomes faster, the fiber membrane thickness becomes thinner, the water permeation path is shorter, and the maximum water permeation rate increases; because the perfusion speed interval does not change, the pore size of the surface layer and the bottom layer does not change much.

[0101] Example 6 has the same increment of the perfusion speed per second as Example 1, but the perfusion interval is changed from 0-2 ml h -1 to 0-3 ml h -1 , the interval becomes larger, the fiber membrane thickness becomes thicker, the water permeation path is longer, and the maximum water permeation rate decreases; because the perfusion speed interval changes, the maximum pore size of the surface layer increases.

[0102] The above examples provided are not intended to limit the scope covered by the present application, and the described steps are not intended to limit the execution order. Those skilled in the art can make obvious improvements to the present application based on the existing common knowledge, which also falls within the protection scope defined by the claims of the present application.

Claims

1. A method for preparing a single-layer nanofiber membrane with high efficiency unidirectional water conduction and rapid drying, characterized in that, The method includes the following: (1) Prepare polymer spinning solution and prepare a single-layer nanofiber membrane with continuous gradient hierarchical pores by electrospinning technology: Electrospinning parameters: voltage is 10~35 kV, and the infusion rate is 0 ml / h. -1 It increases linearly to 1–5 ml h -1 The infusion rate increment was 0.1–10 μL / s. -1 The receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃, and the humidity is 20-70%. (2) The monolayer nanofiber membrane with continuous gradient hierarchical pores obtained in step (1) is placed in a hydrophobic modifier for local hydrophobic modification. The hydrophobic modifier is any one of polyurethane or silane coupling agents; (3) Take a patterned hollow template and place it on one side of the hydrophobic modified monolayer nanofiber membrane in step (2) to perform hydrophilic modification, thereby obtaining a highly efficient unidirectional hydrophobic and quick-drying monolayer nanofiber membrane. The hydrophilic modification method is either plasma treatment or photo-excited polymerization. The plasma treatment involves placing the sample to be treated in a plasma treatment machine, setting the cleaning time to 10–600 s, the air flow rate to 100–200 ml / min, and the power to 40–300 W. The photo-induced polymerization method involves immersing the sample to be treated in a mixture of a hydrophilic modifier and a photoinitiator. The concentration of the hydrophilic modifier is 5–50 wt%, and the mass ratio of the hydrophilic modifier to the photoinitiator is 10:1 to 1:

1. The sample is then placed under a light source of the wavelength corresponding to the photoinitiator, with a wavelength of 250–420 nm and an irradiation time of 30–300 s. After irradiation, the sample is cleaned and dried. The perforated hole diameter of the patterned perforated template is 0.5-5 mm, and the perforation spacing is 5-20 mm. The patterned cutout template is any one of perforated cellulose paper, tape, tin foil, or plastic board; The unidirectional water-conducting and quick-drying single-layer nanofiber membrane has a unidirectional water-conducting rate of (1.5~2.5)×10⁻⁶. 5 g / (m 2 ·h).

2. The preparation method according to claim 1, characterized in that, The concentration of the polymer spinning solution in step (1) is 5-20 wt%.

3. The preparation method according to claim 1, characterized in that, The polymer used in the polymer spinning solution in step (1) is one or more of polycaprolactone, polypropylene, polyacrylonitrile, polyvinyl alcohol, polyethylene glycol, and sodium polyacrylate.

4. The preparation method according to claim 1, characterized in that, The solvent used in the polymer spinning solution in step (1) is one or more of water, toluene, xylene, acetone, cyclohexanone, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide.

5. The preparation method according to claim 1, characterized in that, The electrospinning parameters in step (1) are: voltage of 10~35 kV, and injection speed of 0 ml / h. -1 It increases linearly to 1–3 ml h -1 The infusion rate increment was 0.1–5 μL / s. -1 The receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃, and the humidity is 20-70%.

6. The preparation method according to claim 1, characterized in that, The electrospinning parameters in step (1) are: voltage of 10~35 kV, and injection speed of 0 ml / h. -1 It increases linearly up to 2 ml h -1 The infusion rate increment was 1–1.5 μL / s. -1 The receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃, and the humidity is 20-70%.

7. The preparation method according to claim 1, characterized in that, The electrospinning parameters in step (1) are: voltage of 10~35 kV, and injection speed of 0 ml / h. -1 It increases linearly up to 4 ml h -1 The infusion rate increment was 1–1.5 μL / s. -1 The receiving distance is 10-30 cm, the spinning environment temperature is 25-50℃, and the humidity is 20-70%.

8. The preparation method according to claim 1, characterized in that, The electrospinning parameters in step (1) are: voltage of 15 kV, and injection speed of 0 ml / h. -1 It increases linearly up to 2 ml h -1 The infusion rate increment was 1.2 μL / s. -1 The receiving distance is 15 cm, the spinning environment temperature is 30℃, and the humidity is 50%.

9. The preparation method according to claim 1, characterized in that, The perforated hole diameter of the patterned perforated template in step (3) is 1~3 mm, and the perforated dot matrix spacing is 7~9 mm.

10. The preparation method according to claim 1, characterized in that, The hydrophilic modifier is an oligomer with a concentration of 10-60 wt%, wherein the oligomer is one or more of hydroxyethyl methacrylate, polyethylene glycol diacrylate, and acrylates.

11. The preparation method according to claim 1, characterized in that, The photoinitiator is one or both of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone and benzophenone.

12. The highly efficient, unidirectional, and quick-drying single-layer nanofiber membrane prepared by the method according to any one of claims 1 to 11.

13. The application of the highly efficient unidirectional water-guiding, quick-drying single-layer nanofiber membrane of claim 12 in functional clothing, medical and health care, filtration and separation, and flow control.

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