CN106930007B - Micro-nanofiber composite membrane with water unidirectional conductivity and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of preparation methods of micro nanometer fiber composite membrane with the unidirectional conducting power of moisture, which is characterized in that Dopamine hydrochloride is dissolved in trishydroxymethylaminomethane buffer solution, dopamine solution is made；Non-woven cloth is immersed in above-mentioned dopamine solution, dipping makes it form a poly-dopamine film in fiber surface at room temperature, and poly-dopamine is made and pre-processes non-woven cloth；Hydrophilic nano material is dissolved in solvent, ultrasound makes nano material evenly dispersed, hydrophilic polymers are dissolved in above-mentioned gained homogeneous solution, it is pre-processed by electrospinning process in poly-dopamine and prepares hydrophilic fiber layer on non-woven cloth, to obtain the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture.Micro nanometer fiber composite membrane produced by the present invention has the unidirectional conducting power of efficient moisture, i.e., has unidirectional conducting power simultaneously to liquid water and vaporous water, achieve the effect that wet-guide quick-drying, can be used for clothes or doctor defends the fields of grade.

Description

Micro-nanofiber composite membrane with water unidirectional conductivity and preparation method thereof

technical field

The invention belongs to the technical field of functional micro-nano composite fiber materials, and in particular relates to a non-woven fabric and an electrospinning fiber composite film with moisture unidirectional conductivity and a preparation method thereof. One-way conduction between water and gaseous water.

Background technique

Wettability is one of the important properties of solid surfaces, which is jointly determined by surface chemical composition and surface roughness. Materials with wettability gradients can be obtained by chemical gradient modification or construction of surface structural gradients, from the hydrophobic region to the surface. The hydrophilic area creates an additional pressure difference, and the water droplets are transferred from the hydrophobic side of the material to the hydrophilic side, enabling directional driving of the liquid. Typically, this material is used as a garment fabric with a hydrophobic inner layer and a hydrophilic outer layer. Sweat is transferred to the outer layer of the fabric under the action of the wetting gradient effect or the differential capillary effect and volatilizes quickly, so as to achieve the effect of moisture absorption and quick drying. At present, a lot of research has been done at home and abroad on the preparation and application of unidirectional water-conducting functional micro-nano composite fiber materials. The related patented technologies include: Preparation of a superhydrophobic and superhydrophilic electrospinning nanofiber composite membrane Method (CN102605554A), a composite fiber membrane with unidirectional water permeability and its preparation method (CN102691175A), a spunlace nonwoven material with unidirectional water guiding function and its preparation method and application (CN103938368A), a A composite membrane for regulating the range of liquid unidirectional permeation and its preparation method (CN105664730A), etc., its research direction mainly focuses on the unidirectional water conductivity, and the preparation and research of the micro-nanofiber composite membrane with unidirectional moisture conductivity are relatively few. , and the design of a multifunctional and practical moisture one-way conduction composite material is of great significance for the theoretical research and practical application of one-way moisture conduction.

Electrospinning technology is a method that can directly and continuously prepare polymer nanofibers. Combined with hydrophilic modification or material doping, the hydrophilicity, hydrophobicity and microstructure of fibers can be effectively controlled to obtain materials with superhydrophilic properties. Compared with traditional moisture-absorbing and quick-drying fabrics, the electrospun nanofiber membrane has a large specific surface area and strong wicking effect, and the obtained micro-nanofiber composite membrane has excellent unidirectional water conduction, moisture conduction and quick drying properties.

SUMMARY OF THE INVENTION

The problem to be solved by the present invention is to provide a method for preparing a micro-nanofiber composite membrane with unidirectional water conductivity. The composite membrane prepared by the method has unidirectional conductivity for both liquid water and gaseous water.

In order to solve the above problems, the present invention provides a preparation method of a micro-nanofiber composite membrane with unidirectional moisture conductivity, which is characterized in that comprising the following steps:

Step 1: Choose an untreated nonwoven;

The second step: prepare tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with tris-hydroxymethylaminomethane and hydrochloric acid, and dissolve dopamine hydrochloride in the tris-hydroxymethylaminomethane buffer solution to prepare dopamine solution;

The third step: immersing the non-woven fabric in the dopamine solution obtained in the second step, and dipping it at room temperature to form a polydopamine film on the surface of the fiber to obtain a polydopamine pretreated non-woven fabric;

The fourth step: dissolving the hydrophilic nanomaterial in the solvent, ultrasonically dispersing the nanomaterial uniformly, dissolving the hydrophilic polymer in the solvent to obtain a spinning solution, and pretreating the non-woven fabric in polydopamine by electrospinning A layer of hydrophilic nanofiber membrane is deposited on the cloth, so as to obtain the micro-nanofiber composite membrane with unidirectional water conductivity.

Preferably, the nonwovens in the first step are polyester spunbond nonwovens, polypropylene spunbond nonwovens, polyethylene spunbond nonwovens, polyester meltblown nonwovens, Any one or more of polypropylene meltblown nonwovens and polyethylene meltblown nonwovens.

Preferably, the fiber diameter of the non-woven material in the first step is 5-20 μm, and the thickness is 50-200 μm.

Preferably, the concentration of the Tris-HCl buffer solution in the second step is 0.005-0.05 mol/L, and the pH is 7-9.

Preferably, the concentration of the dopamine solution in the second step is 0.2-2 g/L.

Preferably, the dipping time in the third step is 15-120 min.

Preferably, the hydrophilic nanomaterial in the fourth step is any one or more of carbon nanotubes, silica nanoparticles, nano-calcium carbonate, metal and metal oxide nanoparticles.

More preferably, the metal nanoparticles are silver nanoparticles; the metal oxide nanoparticles are any one or more of titanium dioxide nanoparticles, zinc oxide nanoparticles and zirconia nanoparticles.

Preferably, the mass fraction of hydrophilic nanoparticles in the spinning solution in the fourth step is 0% to 5%.

Preferably, the hydrophilic polymer in the fourth step is a water-soluble polymer or a water-insoluble polymer; the water-soluble polymer is any one of polyvinyl alcohol, sodium polyacrylate and polyacrylamide or several, when preparing this type of polymer electrospinning solution, a cross-linking agent must be added to the solution; the water-insoluble polymers are cellulose acetate, chitosan, polyacrylonitrile, ethylene/vinyl alcohol copolymer, poly Any one or more of amide and polyimide.

More preferably, when the water-soluble polymer in the described fourth step is polyvinyl alcohol, the crosslinking agent is any one or more of glutaraldehyde, maleic anhydride and triethylene glycol; When the water-soluble polymer in the described fourth step is sodium polyacrylate, the cross-linking agent is any one of hydroxyethyl methacrylate, N,N-methylene bisacrylamide and polyethylene glycol diacrylate. one or more; when the water-soluble polymer in the described fourth step is polyacrylamide, the cross-linking agent is any one of glutaraldehyde, N,N-methylenebisacrylamide and polyethanol diacrylate species or several.

Preferably, the solvent in the fourth step is deionized water, acetone, acetic acid, N,N-dimethylformamide, N,N-dimethylacetamide, isopropanol, tetrahydrofuran, formic acid, ethylene glycol Any one or more of alcohol, glycerol, dichloromethane, carbon tetrachloride and dimethyl sulfoxide.

Preferably, the mass concentration of the hydrophilic polymer in the spinning solution in the fourth step is 5-30%.

Preferably, the voltage of the electrospinning in the fourth step is 10-50 kV, the receiving distance is 10-30 cm, the perfusion speed of the spinning solution is 0.2-5 mL/h, the diameter of the obtained fiber is 50 nm-2 μm, and the fiber membrane The thickness is 10 to 150 μm.

The present invention also provides a micro-nanofiber composite membrane with unidirectional moisture conductivity, which is prepared by using the above-mentioned preparation method for the micro-nanofiber composite membrane with unidirectional moisture conductivity.

Preferably, the composite membrane can conduct liquid water or/and gaseous water unidirectionally.

The micro-nano fiber composite membrane prepared by the invention comprises a hydrophilic layer and a hydrophobic layer, the hydrophilic layer is an electrospinning nano-fiber membrane, and the hydrophobic layer is a dopamine modified non-woven fabric. The wetting gradient difference of the composite membrane in the direction perpendicular to the membrane plane can be determined by changing the pH value of the Tris-HCl buffer solution in the second step, the concentration of dopamine hydrochloride, the treatment time in the third step, and the hydrophilicity in the fourth step. The proportion of hydrophilic nanoparticles doped in the polymer can be adjusted, so that excellent unidirectional water conductivity can be obtained.

The micro-nano fiber composite film prepared by the invention has a moisture permeability of ≥ 10000 g/m2/d along the non-woven fabric facing the surface of the electrospun nano fiber film, a unidirectional transfer index ≥ 1000, a comprehensive index of liquid water dynamic transfer ≥ 0.95, and an electrostatic transfer index ≥ 0.95. The moisture permeability of the spun nanofiber membrane facing the non-woven fabric surface is less than or equal to 4000g/m2/d, the unidirectional transfer index is less than or equal to -500, and the comprehensive index of dynamic transfer of liquid water is less than or equal to 0.4.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The dopamine-modified non-woven fabric layer and the electrospinning nanofiber membrane layer in the composite membrane of the present invention are prepared by in-situ polymerization and electrospinning, respectively. The method is simple, and combining hydrophilic modification and nanomaterial doping can effectively control the hydrophilicity and hydrophobicity and microstructure of fibers, and obtain materials with superhydrophilic properties;

(2) The hydrophobic layer in the composite film of the present invention is composed of a hydrophobic non-woven fabric. The selected non-woven material itself is hydrophobic, and the fiber has poor hygroscopicity. On this basis, dopamine modification is performed to form a layer of hydrophilicity on the surface of the fiber. In the water-based polydopamine film, the chemical properties inside the fiber have not changed, and it still maintains a certain hydrophobicity. Therefore, under the action of the capillary effect, the water conductivity of the hydrophobic layer material is enhanced, but the hygroscopicity has not changed. ;

(3) The hydrophilic layer in the composite membrane of the present invention is composed of a hydrophilic nanofiber membrane, and the hydrophilicity of the fiber membrane is further improved by doping with hydrophilic nanomaterials, and the micro/nanostructure of the fiber membrane is given dual-dimensional roughness , thus achieving superhydrophilicity. Compared with traditional fibers, electrospun fibers have a smaller diameter and a larger specific surface area. When water is transferred from the hydrophobic surface to the hydrophilic surface, it can evaporate quickly, thereby achieving excellent unidirectional water conduction, moisture conduction and quick drying performance.

Description of drawings

FIG. 1 is an electron microscope image of the micro-nanofiber composite film prepared in Example 1. FIG.

Detailed ways

In order to make the present invention more obvious and comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.

The weight-average molecular weight of polyvinyl alcohol used in Examples 1-8 is 11-13W, the weight-average molecular weight of sodium polyacrylate is 5000, the weight-average molecular weight of polyacrylamide is 100W, the weight-average molecular weight of cellulose acetate is 10W, The weight average molecular weight of chitosan is 30W, the weight average molecular weight of polyacrylonitrile is 10W, the weight average molecular weight of ethylene/vinyl alcohol copolymer is 5W, the weight average molecular weight of polyamide is 3W and the weight average molecular weight of polyimide is 5W. Solvents Deionized water, acetone, acetic acid, N,N-dimethylformamide, N,N-dimethylacetamide, isopropanol, tetrahydrofuran, formic acid, ethylene glycol, glycerol, dichloromethane, tetrahydrofuran Both carbon chloride and dimethyl sulfoxide were produced by Shanghai Jingpure Reagent Co., Ltd. The high-voltage power supply adopts the DW-P303-1ACD8 type produced by Tianjin Dongwen High-voltage Power Supply Factory.

Example 1

As shown in Figure 1, a micro-nanofiber composite membrane with unidirectional water conductivity is composed of a superhydrophilic layer (a) and a hydrophobic layer (b). The preparation method is as follows:

The first step: provide a polypropylene spunbond non-woven fabric with a fiber diameter of 10 μm and a thickness of 100 μm;

The second step: prepare a 0.005mol/L tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 7 with tris-hydroxymethylaminomethane and hydrochloric acid, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 1 g of dopamine hydrochloride and dissolve it in 1 L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polypropylene spunbond non-woven fabric in the above-mentioned dopamine solution, soak it for 1 hour at room temperature to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry at 60 °C to obtain a polydopamine pretreated non-woven fabric. woven cloth;

The fourth step: dissolving the hydrophilic silica nanoparticles in water, ultrasonically dispersing the nanoparticles uniformly, to prepare a silica solution with a mass fraction of 2%; dissolving polyvinyl alcohol in the above prepared solution to prepare the mass The polyvinyl alcohol electrospinning solution with a fraction of 15%, and glutaraldehyde was added as a cross-linking agent, and the mass fraction of glutaraldehyde accounted for 5% of polyvinyl alcohol, and the spinning solution was obtained by stirring evenly. A layer of hydrophilic nanofiber membrane was deposited on the dopamine pretreated non-woven fabric, the spinning voltage was 40kV, the receiving distance was 20cm, the perfusion speed of the spinning solution was 2mL/h, the obtained fiber diameter was 300nm, and the fiber membrane thickness was 30μm. Thereby, the micro-nanofiber composite membrane with the unidirectional water conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1050, and the liquid water is 1050. The comprehensive index of dynamic transfer is 0.96; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 11200g/m2/d; along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 4700g/m2/d, the unidirectional transfer index is -470, and the comprehensive index of liquid water dynamic transfer is 0.35.

Example 2

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

The first step: provide a polyester spunbond non-woven fabric with a fiber diameter of 7 μm and a thickness of 80 μm;

The second step: prepare a 0.01 mol/L tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 8 with tris-hydroxymethylaminomethane and hydrochloric acid, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 2g of dopamine hydrochloride and dissolve it in 1L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polyester spunbond non-woven fabric in the above-mentioned dopamine solution, soak it at room temperature for 0.5 h to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry it at 60°C to obtain polydopamine pretreatment Non-woven;

The fourth step: dissolving the hydrophilic titanium dioxide nanoparticles in water, and ultrasonically dispersing the nanoparticles uniformly to obtain a titanium dioxide solution with a mass fraction of 1%; dissolving sodium polyacrylate in the above prepared solution to prepare a mass fraction of 20% The sodium polyacrylate electrospinning solution was added, and hydroxyethyl methacrylate was added as a crosslinking agent, and the mass fraction of hydroxyethyl methacrylate accounted for 5% of sodium polyacrylate, and the spinning solution was obtained by stirring evenly. A layer of hydrophilic nanofiber membrane was deposited on the polydopamine pretreated non-woven fabric, the spinning voltage was 30kV, the receiving distance was 20cm, the perfusion speed of the spinning solution was 1mL/h, the obtained fiber diameter was 200nm, and the fiber membrane thickness was 40μm. Thereby, the micro-nanofiber composite membrane with the unidirectional water conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1120, and the liquid water is 1120. The comprehensive index of dynamic transfer is 0.97; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 12100g/m2/d; along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 3700g/m2/d, the unidirectional transfer index is -380, and the comprehensive index of liquid water dynamic transfer is 0.32.

Example 3

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

The first step: provide a polyethylene spunbond non-woven fabric with a fiber diameter of 5 μm and a thickness of 80 μm;

The second step: using tris(hydroxymethyl)aminomethane and hydrochloric acid to prepare a 0.02mol/L tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 8.5, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 1 g of dopamine hydrochloride and dissolve it in 1 L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polyethylene spunbond non-woven fabric in the above-mentioned dopamine solution, soak it at room temperature for 2 hours to form a polydopamine film on the fiber surface, wash it with distilled water and dry at 60 °C to obtain a polydopamine pretreated non-woven fabric. woven cloth;

Step 4: Dissolve the hydrophilic carbon nanotubes in acetone, and ultrasonically disperse the nanomaterials uniformly to obtain a carbon nanotube solution with a mass fraction of 4%; dissolve cellulose acetate in the above-prepared solution to prepare the mass The cellulose acetate electrospinning solution with a fraction of 30% was stirred evenly to obtain a spinning solution. A layer of hydrophilic nanofiber film was deposited on the polydopamine pretreated non-woven fabric by electrospinning method. The spinning voltage was 50 kV. The distance was 25 cm, the perfusion rate of the spinning solution was 2 mL/h, the diameter of the obtained fiber was 300 nm, and the thickness of the fiber membrane was 80 μm. Thereby, the micro-nanofiber composite membrane with the unidirectional water conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1310, and the liquid water is 1310. The comprehensive index of dynamic transfer is 0.99; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 14300g/m2/d; along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 3200g/m2/d, the one-way transfer index is -650, and the comprehensive index of liquid water dynamic transfer is 0.34.

Example 4

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

The first step: provide a polyester spunbond non-woven fabric with a fiber diameter of 8 μm and a thickness of 100 μm;

The second step: using tris-hydroxymethylaminomethane and hydrochloric acid to prepare a 0.03 mol/L tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 8.5, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 1.5 g of dopamine hydrochloride and dissolve it in 1 L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polyester spunbond non-woven fabric in the above dopamine solution, soak it at room temperature for 1.5 hours to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry at 60 °C to obtain polydopamine pretreatment Non-woven;

The fourth step: dissolving the hydrophilic nano calcium carbonate in acetic acid, ultrasonically dispersing the nanoparticles uniformly, to prepare a calcium carbonate solution with a mass fraction of 3%; dissolving chitosan in the above prepared solution to prepare a mass fraction of 20% chitosan electrospinning solution, a layer of hydrophilic nanofiber film was deposited on polydopamine pretreated non-woven fabric by electrospinning method, the spinning voltage was 30kV, the receiving distance was 25cm, and the perfusion speed of the spinning solution was was 2 mL/h, the diameter of the obtained fiber was 350 nm, and the thickness of the fiber membrane was 50 μm. Thereby, the micro-nanofiber composite membrane with the unidirectional water conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1120, and the liquid water is 1120. The comprehensive index of dynamic transfer is 0.98; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 12700g/m2/d; along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 4500g/m2/d, the one-way transfer index is -360, and the comprehensive index of liquid water dynamic transfer is 0.39.

Example 5

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

Step 1: Provide a polypropylene meltblown nonwoven with a fiber diameter of 4 μm and a thickness of 50 μm;

The second step: using tris(hydroxymethyl)aminomethane and hydrochloric acid to prepare a 0.02mol/L tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 8.5, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 2g of dopamine hydrochloride and dissolve it in 1L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polypropylene melt-blown non-woven fabric in the above-mentioned dopamine solution, soak it at room temperature for 2 hours to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry it at 60 °C to obtain a polydopamine pretreated non-woven fabric. woven cloth;

The fourth step: dissolving the hydrophilic zinc oxide nanoparticles in water, ultrasonically dispersing the nanoparticles uniformly, to prepare a zinc oxide solution with a mass fraction of 5%; dissolving the polyacrylonitrile in the above prepared solution to prepare a mass fraction 18% polyacrylonitrile electrospinning solution, a layer of hydrophilic nanofiber film was deposited on the polydopamine pretreated non-woven fabric by electrospinning method, the spinning voltage was 35kV, the receiving distance was 25cm, the perfusion of the spinning solution The speed was 1.5 mL/h, the obtained fiber diameter was 350 nm, and the fiber membrane thickness was 100 μm. Thereby, the micro-nanofiber composite membrane with unidirectional water conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1350, and the liquid water is 1350. The dynamic transfer comprehensive index is 0.99; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 14100g/m2/d, along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 2900g/m2/d, the one-way transfer index is -550, and the comprehensive index of liquid water dynamic transfer is 0.37.

Example 6

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

The first step: provide a polyester meltblown nonwoven fabric with a fiber diameter of 5 μm and a thickness of 80 μm;

The second step: prepare a 0.05mol/L Tris-HCl buffer solution with a pH value of 8.5 with tris-hydroxymethylaminomethane and hydrochloric acid, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 0.5g of dopamine hydrochloride and dissolve it in 1L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

The third step: Immerse the polyester melt-blown non-woven fabric in the above-mentioned dopamine solution, soak it at room temperature for 1 hour to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry at 60 ℃ to obtain the polydopamine pretreated non-woven fabric. woven cloth;

The fourth step: dissolve the hydrophilic zirconia nanoparticles in isopropanol, and ultrasonically disperse the nanoparticles uniformly to obtain a zirconia solution with a mass fraction of 5%; dissolve the ethylene/vinyl alcohol copolymer in the above-mentioned The electrospinning solution of ethylene/vinyl alcohol copolymer with a mass fraction of 10% was prepared in the preparation solution, and a layer of hydrophilic nanofiber film was deposited on the polydopamine pretreated non-woven fabric by electrospinning method, and the spinning voltage was 30kV. The receiving distance was 20 cm, the perfusion rate of the spinning solution was 1 mL/h, the diameter of the obtained fiber was 300 nm, and the thickness of the fiber membrane was 40 μm. Thereby, the micro-nanofiber composite membrane with water unidirectional conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1150, and the liquid water The dynamic transfer comprehensive index is 0.96; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 10500g/m2/d, along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 3500g/m2/d, the one-way transfer index is -560, and the comprehensive index of liquid water dynamic transfer is 0.36.

Example 7

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

The first step: provide a polyethylene meltblown nonwoven fabric with a fiber diameter of 4 μm and a thickness of 70 μm;

The second step: using tris(hydroxymethyl)aminomethane and hydrochloric acid to prepare a 0.07mol/L tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 7. The pH value of the solution can be adjusted by hydrochloric acid. Weigh 1 g of dopamine hydrochloride and dissolve it in 1 L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polyethylene melt-blown non-woven fabric in the above-mentioned dopamine solution, immerse it at room temperature for 1 hour to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry at 60 °C to obtain a polydopamine pretreated non-woven fabric. woven cloth;

The fourth step: dissolving the hydrophilic silica nanoparticles in formic acid, ultrasonically dispersing the nanoparticles uniformly, to prepare a silica solution with a mass fraction of 5%; dissolving the polyamide in the above prepared solution to prepare A polydopamine electrospinning solution with a mass fraction of 15% was deposited on a polydopamine-pretreated non-woven fabric by electrospinning. The spinning voltage was 30 kV, and the receiving distance was 20 cm. The perfusion rate was 1 mL/h, the diameter of the obtained fibers was 100 nm, and the thickness of the fiber membrane was 30 μm. Thereby, the micro-nanofiber composite film with the unidirectional water conductivity is obtained. According to the national standard GB/T21655.2-2009, the unidirectional transfer index of the film along the non-woven fabric facing the electrospinning nanofiber film surface is 1180, and the liquid water is 1180. The comprehensive index of dynamic transfer is 0.97; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 11200g/m2/d, along the electrospun nanofiber membrane The moisture permeability facing the non-woven fabric surface is 3200g/m2/d, the one-way transfer index is -580, and the comprehensive index of liquid water dynamic transfer is 0.34.

Example 8

A micro-nanofiber composite membrane with water unidirectional conductivity is composed of a super-hydrophilic layer and a hydrophobic layer, and the preparation method is as follows:

Step 1: Provide a polypropylene meltblown nonwoven fabric with a fiber diameter of 5 μm and a thickness of 80 μm;

The second step: using tris(hydroxymethyl)aminomethane and hydrochloric acid to prepare a 0.01mol/L tris-hydroxymethylaminomethane hydrochloride (Tris-HCl) buffer solution with a pH value of 8.5, and the pH value of the solution can be adjusted by hydrochloric acid. Weigh 2g of dopamine hydrochloride and dissolve it in 1L of tris buffer solution to prepare a dopamine solution, and the solution is ready to use;

Step 3: Immerse the polypropylene melt-blown non-woven fabric in the above-mentioned dopamine solution, soak it at room temperature for 2 hours to form a polydopamine film on the surface of the fiber, wash it with distilled water and dry it at 60 °C to obtain a polydopamine pretreated non-woven fabric. woven cloth;

The fourth step: dissolving the hydrophilic titanium dioxide nanoparticles in N-N dimethylformamide, and ultrasonically dispersing the nanoparticles uniformly to obtain a titanium dioxide solution with a mass fraction of 5%; dissolving the polyimide in the above prepared solution A polyimide electrospinning solution with a mass fraction of 20% was prepared in the solution, and a layer of hydrophilic nanofiber film was deposited on the polydopamine pretreated non-woven fabric by electrospinning method. The spinning voltage was 30kV and the receiving distance was 25cm. , the perfusion speed of the spinning solution was 2 mL/h, the diameter of the obtained fiber was 200 nm, and the thickness of the fiber membrane was 50 μm. Thereby, the micro-nanofiber composite membrane with water unidirectional conductivity is obtained. According to the national standard GB/T 21655.2-2009, the unidirectional transfer index of the membrane along the non-woven fabric facing the electrospinning nanofiber membrane surface is 1290, and the liquid water dynamic The comprehensive transfer index is 0.99; according to the national standard GB/T12704.2-2009 positive cup method, the moisture permeability of the film along the non-woven fabric facing the electrospun nanofiber membrane surface is 12400g/m2/d, along the electrospun nanofiber membrane facing The moisture permeability of the non-woven fabric surface is 3600g/m2/d, the one-way transfer index is -620, and the comprehensive index of liquid water dynamic transfer is 0.35.

Claims (16)

1. a kind of preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture, which is characterized in that including with Lower step:

Step 1: one untreated non-woven cloth of selection；

Step 2: Tri(Hydroxymethyl) Amino Methane Hydrochloride buffer solution is prepared with trishydroxymethylaminomethane and hydrochloric acid, by hydrochloric acid Dopamine, which is dissolved in Tri(Hydroxymethyl) Amino Methane Hydrochloride buffer solution, is made dopamine solution；

Step 3: non-woven cloth is immersed in dopamine solution made from second step, dipping makes it in fiber surface shape at room temperature At poly-dopamine film, poly-dopamine is made and pre-processes non-woven cloth；

Step 4: hydrophilic nano material is dissolved in solvent, ultrasound makes nano material evenly dispersed, by hydrophilic polymers It is dissolved in solvent, obtains spinning solution, pre-processed by electrospinning process in poly-dopamine and deposit one layer of parent on non-woven cloth Water type nano fibrous membrane, to obtain the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture.

2. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the non-woven cloth in the first step is spunbond polyester method non-woven cloth, PP cellular, polyethylene Spunbonded Nonwovens, polyester meltblown method non-woven cloth, polypropylene melt spray non-woven cloth and polyethylene meltblown method non-woven cloth In any one or a few.

3. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as claimed in claim 1 or 2, It is characterized in that, the fibre diameter of the non-woven cloth in the first step is 5~20 μm, with a thickness of 50~200 μm.

4. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the concentration of the Tri(Hydroxymethyl) Amino Methane Hydrochloride buffer solution in the second step is 0.005~0.05mol/L, PH value is 7~9.

5. the preparation method of the micro nanometer fiber composite membrane as described in claim 1 or 4 with the unidirectional conducting power of moisture, It is characterized in that, the dopamine solution concentration in the second step is 0.2~2g/L.

6. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the dip time in the third step is 15~120min.

7. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the hydrophilic nano material in the 4th step is carbon nanotube, nano SiO 2 particle, nanometer calcium carbonate, gold Any one or a few in metal nano-particle or metal oxide nanoparticles.

8. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as claimed in claim 7, special Sign is that the metal nanoparticle is nano silver；The metal oxide nanoparticles are titania nanoparticles, oxidation Any one or a few in zinc nanoparticles and Zirconium oxide nano grain.

9. the preparation method of the micro nanometer fiber composite membrane as claimed in claim 1 or 7 with the unidirectional conducting power of moisture, It is characterized in that, the mass fraction of hydrophilic nano material is 0%~5% in the spinning solution in the 4th step.

10. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the hydrophilic polymers in the 4th step are water-soluble polymer or non-soluble polymer；The water-soluble poly Conjunction object is any one or a few in polyvinyl alcohol, Sodium Polyacrylate and polyacrylamide, is preparing such polymer electrospinning When solution, crosslinking agent must be added into solution；Non-soluble polymer be cellulose acetate, chitosan, polyacrylonitrile, ethylene/ Any one or a few in ethenol copolymer, polyamide and polyimides.

11. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as claimed in claim 10, Be characterized in that, the water-soluble polymer in the 4th step be polyvinyl alcohol when, crosslinking agent be glutaraldehyde, maleic anhydride and Any one or a few in triethylene-glycol；When water-soluble polymer in 4th step is Sodium Polyacrylate, crosslinking Agent be hydroxyethyl methacrylate, N,N methylene bis acrylamide and polyethyleneglycol diacrylate in any one or it is several Kind；When water-soluble polymer in 4th step is polyacrylamide, crosslinking agent is glutaraldehyde, N, N- methylene bisacrylamide acyl Any one or a few in amine and polyethanol diacrylate.

12. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the solvent in the 4th step is deionized water, acetone, acetic acid, n,N-Dimethylformamide, N, N- dimethylacetamide It is any one in amine, isopropanol, tetrahydrofuran, formic acid, ethylene glycol, glycerine, methylene chloride, carbon tetrachloride and dimethyl sulfoxide Kind is several.

13. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the mass concentration of hydrophilic polymers is 5~30% in the spinning solution in the 4th step.

14. the preparation method of the micro nanometer fiber composite membrane with the unidirectional conducting power of moisture as described in claim 1, special Sign is that the voltage of the electrostatic spinning in the 4th step is 10~50kV, and receiving distance is 10~30cm, the filling of spinning solution Note speed is 0.2~5mL/h, and gained fibre diameter is 50nm~2 μm, and tunica fibrosa is with a thickness of 10~150 μm.

15. a kind of compound using the micro nanometer fiber described in claim 1-14 any one with the unidirectional conducting power of moisture The preparation method of the film micro nanometer fiber composite membrane obtained with the unidirectional conducting power of moisture.

16. as claimed in claim 15 with the micro nanometer fiber composite membrane of the unidirectional conducting power of moisture, which is characterized in that institute Liquid water or/and vaporous water can unidirectionally be conducted by stating composite membrane.