Water-proof oil-proof one-way sweat-guiding Janus fabric based on pH response and preparation method of water-proof oil-proof one-way sweat-guiding Janus fabric

Abstract

The invention belongs to the technical field of functional materials, and provides a waterproof, oil-proof and unidirectional sweat-guiding Janus fabric based on pH response and a preparation method thereof in order to solve the problem that in the prior art, the outer side of a Janus fabric does not have a waterproof function, and the outer side of a garment is easily wetted by water in rainy days and high-humidity environments, so that the fabric loses a unidirectional sweat-guiding function. The waterproof and oilproof one-way sweat-guiding Janus fabric based on pH response comprises a base material, a pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer is arranged on the outer surface of the base material, and a super-hydrophobic-oleophobic layer is arranged on the surface of the side, away from the base material, of the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer. The Janus fabric prepared by the invention has unidirectional sweat-guiding, waterproof and oil-proof properties, and can be used as a dual-purpose functional textile.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and in particular relates to a pH-responsive, waterproof, oil-proof, unidirectional sweat-conducting Janus fabric and a preparation method thereof. Background Art

[0002] Thermal and moisture management textiles can spontaneously adjust the microclimate between the skin and the inner surface of the fabric without external interference, making the human body comfortable, and are therefore highly sought after by consumers. Moisture-absorbing and quick-drying textiles are considered to be one of the effective methods for regulating the thermal and moisture functions of textiles. Moisture-absorbing and quick-drying textiles can quickly transfer the sweat produced by the human body from the inside of the fabric to the outside, and evaporate it quickly, thereby keeping the skin surface dry and meeting the physiological comfort requirements of the human body.

[0003] Janus textiles are made by directly compounding hydrophilic and hydrophobic materials or performing hydrophobic (hydrophilic) modification on one side of the surface of a hydrophilic (hydrophobic) substrate, thereby constructing a hydrophobic-hydrophilic wetting gradient in the thickness direction of the fabric, thereby achieving unidirectional conduction of sweat. Hydrophobic / hydrophilic Janus fabrics can not only quickly conduct sweat from the skin side, but also prevent the back-infiltration of sweat from the outside. Compared with some single-layer fabrics prepared with special fibers such as special shapes and pore structures, they have shown great advantages in unidirectional sweat conduction and are currently one of the most promising methods for preparing moisture-absorbing and quick-drying textiles. However, although many unidirectional sweat-conducting Janus fabrics have been reported, such fabrics generally do not have oil-proof properties. The fabrics are easily contaminated by oily liquids that are often exposed in life, which not only brings inconvenience to the wearer of the clothing, but also causes the contaminated part to lose its unidirectional sweat-conducting properties. On the other hand, one-way sweat-conducting fabrics can bring a cool and dry comfortable feeling to the human body by quickly conducting sweat away from the skin side and evaporating it. However, the hydrophilic outer side of the currently developed Janus fabric is easily soaked by water in some high temperature and high humidity environments, causing the fabric to lose its one-way sweat-conducting, moisture-absorbing and quick-drying functions. In high temperature and high humidity environments, the moisture-absorbing and quick-drying functions of the fabric are extremely important for body surface comfort.

[0004] Fu et al. first modified the surface of nylon membrane material with self-organized phytic acid and FeIII by dip coating to obtain a superhydrophilic surface, and then modified the single side of the fabric with PDMS superhydrophobicity to obtain a superhydrophobic / superhydrophilic Janus fabric with unilateral water-conducting function; Ding et al. selectively modified the single side of hydrophobic polyester nonwoven fabric with hydrophobicity by electrospinning technology, and directly modified the hydrophilic polyamide fiber and nanosilver particles on the polyester side to obtain a Janus fabric with hydrophobic / superhydrophilic asymmetric wettability. The Janus fabric has the ability to transport water in a directional manner and can be used for moisture-absorbing and quick-drying textiles.

[0005] The invention patent with publication number CN201810985944.7 discloses a method for preparing a Janus forward osmosis membrane, which membrane is composed of a first surface of a super-hydrophilic polymer microporous membrane, an intermediate layer of a polymer membrane matrix, and a second surface coated with a super-hydrophobic inorganic nanoparticle coating away from the first surface, wherein the wetting time of the first surface of the super-hydrophilic polymer microporous membrane to water droplets is less than 2 seconds, and the water drop contact angle of the second surface coated with the super-hydrophobic inorganic nanoparticle coating is greater than 150°.

[0006] The invention patent with publication number CN202110758316.7 discloses a Janus fabric with unidirectional permeability of droplets and its preparation method. The invention combines the Margangoni effect and capillary force-driven compression at the air-water interface to form a hydrophobic silica nanoparticle self-assembled film on one side of the super-hydrophilic surface fabric to obtain Janus cotton fabric. The water contact angle of the hydrophobic side of the Janus cotton fabric is greater than 120°, while the other side is a super-hydrophilic surface with a water contact angle of 0°, which can be used as a unidirectional moisture conduction or moisture absorption and perspiration material.

[0007] However, such fabrics reported so far usually do not have oil-proof and waterproof properties, and are easily stained by oil in daily life and work, thereby affecting the moisture absorption and quick-drying properties of the fabric. At the same time, they are also unable to exert stable moisture absorption and quick-drying functions in high temperature and high humidity environments.

[0008] The invention patent with publication number CN201911100294.4 discloses a preparation method and application of a double-sided oleophobic superhydrophobic / superhydrophilic Janus-type material. By modifying the hydrophobic-oleophobic coating on one side of the superhydrophilic-oleophobic material, a one-way sweat-conducting fabric with anti-oil function is obtained. However, the outer side of the Janus fabric of this patent invention is superhydrophilic and does not have a waterproof function.

[0009] Pan et al. used ultraviolet curing technology and local shading molds to construct a super-hydrophobic-super-oleophobic coating on one side of the super-hydrophobic / super-oleophobic base fabric obtained after dip coating, and developed a Janus fabric with local super-hydrophobic-super-oleophobic / super-hydrophilic-super-oleophobic channels, which has both oil-proof and unidirectional sweat-conducting functions. The Janus fabric has a certain waterproof performance because the area on the outside that is not irradiated by ultraviolet light maintains super-hydrophobic-super-hydrophobicity, but because the side is locally modified with a super-hydrophilic-super-oleophobic coating, it is easily infiltrated by water. Therefore, the waterproof performance of the Janus fabric is poor, which affects the performance of the fabric in continuous directional sweat conduction and rapid evaporation of sweat in a high humidity environment. Therefore, the defects of the above-mentioned fabrics greatly limit the application and development of moisture-absorbing and quick-drying textiles.

[0010] Therefore, it is necessary to design a Janus fabric that can maintain excellent oil-proof and one-way sweat-conducting function in an environment with high temperature and humidity, can intelligently identify sweat, and can conduct sweat from the inside to the outside, while being water-repellent to water in the external environment. Summary of the invention

[0011] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a pH-responsive, waterproof and oil-proof, one-way sweat-conducting Janus fabric and a preparation method thereof. The Janus fabric prepared by the present invention has the functions of oil-proof, waterproof and breathable, self-cleaning and one-way sweat-conducting.

[0012] The first object of the present invention is to provide a pH-responsive waterproof, oil-proof, unidirectional sweat-conducting Janus fabric, comprising a substrate, a pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer being provided on the outer surface of the substrate, and a superhydrophobic-oleophobic layer being provided on the surface of the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer on the side away from the substrate.

[0013] Preferably, the loading amount of the super hydrophobic-oleophobic layer on the pH-responsive super hydrophobic-oleophobic / super hydrophilic-oleophobic layer is 0.05-0.30 g / cm 2 .

[0014] Preferably, the pH responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer is composed of the following components: a pH responsive monomer, an oleophobic monomer, a photoinitiator and a cross-linker, and the molar ratio of the pH responsive monomer to the oleophobic monomer is 6:1-12, the molar ratio of the pH responsive monomer to the cross-linker is 5-200:1, and the mass of the photoinitiator is 0.5-10wt% of the mass of the pH responsive monomer.

[0015] The second object of the present invention is to provide a method for preparing a pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric, comprising the following steps:

[0016] S1, immersing the substrate in a super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modification solution, causing polymerization and cross-linking reactions under ultraviolet light irradiation, and after the reaction, forming a pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer on the outer surface of the substrate;

[0017] S2, spraying the super-hydrophobic-oleophobic modified solution on the surface of the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer obtained in step S1, which is away from the substrate, and causing polymerization and cross-linking reactions under ultraviolet light. After the reaction is completed, a super-hydrophobic-oleophobic layer is formed on one side of the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer, thereby obtaining the pH-responsive Janus fabric.

[0018] Preferably, in step S1, the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modified solution is prepared by the following method:

[0019] The pH-responsive monomer, the oleophobic monomer, the photoinitiator, the cross-linking agent and the organic solvent are uniformly mixed to obtain a super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modified solution;

[0020] The molar ratio of the pH responsive monomer to the oleophobic monomer is 6:1-12, the molar ratio of the pH responsive monomer to the crosslinking agent is 5-200:1, and the mass of the photoinitiator is 0.5-10wt% of the mass of the pH responsive monomer.

[0021] Preferably, in step S2, the super-hydrophobic-oleophobic modified solution is prepared by the following method:

[0022] The oleophobic monomer, the photoinitiator, the crosslinking agent and the organic solvent are uniformly mixed to obtain a super hydrophobic-oleophobic modified solution;

[0023] The mass ratio of the oleophobic monomer to the crosslinking agent is 200-10:1, and the mass of the photoinitiator is 0.5-10wt% of the total mass of the oleophobic monomer and the crosslinking agent.

[0024] Preferably, in step S1, the pH responsive monomer is any one or more of acrylamide, 2-vinylpyridine, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and diethylaminoethyl acrylate.

[0025] Preferably, in step S1 and step S2, the oleophobic monomers are any one or more of 2-(perfluorodecyl)ethyl methacrylate, 1H,1H-perfluoro-n-decyl methacrylate, 2-(perfluorooctyl)ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, perfluorobutylethylene, perfluorohexylethylene, and perfluorodecylethylene.

[0026] Preferably, in step S1 and step S2, the photoinitiator is any one or more of 2-hydroxy-2-methylpropiophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a,a,-dimethylbenzil ketal, benzophenone, 1-hydroxycyclohexyl benzophenone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0027] Preferably, in step S1 and step S2, the crosslinking agent is any one or more of polyethylene glycol diacrylate, N-carboxyethyl acrylamide, N,N-methylenebisacrylamide, methacryloxy cage silsesquioxane, and 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate.

[0028] Preferably, in step S1 and step S2, the irradiation intensity of the ultraviolet light is 5-120 W / cm 2 , the ultraviolet light wavelength is 365nm, and the illumination time is 10-150min.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. Compared with the one-way sweat-conducting textiles developed on the market, the one-way sweat-conducting Janus fabric prepared in the present invention has an anti-oil stain function, which can effectively prevent the textiles from being contaminated by oil liquids during use, giving the one-way sweat-conducting textiles more functions and higher added value;

[0031] 2. The one-way sweat-conducting Janus fabric prepared by the present invention can identify sweat and water, and can continuously exert excellent one-way sweat-conducting performance in a high temperature and high humidity environment, thereby improving the stability of the moisture absorption and quick-drying function of the Janus fabric and broadening the application scope of the one-way sweat-conducting textiles;

[0032] 3. The one-way sweat-conducting Janus fabric prepared by the present invention has environmental self-adaptation and can be used as a dual-purpose functional textile. When sweat is produced on the surface of the human body in a hot and humid environment, the fabric can be used as a multifunctional textile that is both one-way sweat-conducting, waterproof and oil-proof, and can quickly conduct sweat to keep the body surface dry and comfortable. When the human body is in a dry and comfortable or cold environment, the surface of the fabric is waterproof and oil-proof, keeping the body surface dry and comfortable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the preparation process of the Janus fabric provided by an embodiment of the present invention;

[0034] Figure 2 is the SEM image of the fabric;

[0035] in, Figure 2 a is untreated polyester fabric; Figure 2 b and Figure 2 c are the superhydrophobic-oleophobic / superhydrophilic-oleophobic side and the superhydrophobic-oleophobic side of the Janus fabric of Example 1 of the present invention, respectively;

[0036] Figure 3 It is the EDS element content and distribution diagram of the fabric;

[0037] in, Figure 3 a is untreated polyester fabric; Figure 3 b and Figure 3 c are the superhydrophobic-oleophobic / superhydrophilic-oleophobic side and the superhydrophobic-oleophobic side of the Janus fabric of Example 1 of the present invention, respectively;

[0038] Figure 4The graphs are the changes of the contact angles of water and sweat on the fabric surfaces obtained in Comparative Examples 4 and 5 over time;

[0039] in, Figure 4 a to Figure 4 c are graphs showing the change of contact angle of the fabric surface with time in comparative example 4 with water having pH values ​​of 5, 7 and 10; Figure 4 d is a graph showing the change of the contact angle of hexadecane on the fabric surface obtained in Comparative Example 4 over time; Figure 4 e and Figure 4 f are graphs showing the change of the contact angle of the fabric surface with time obtained in Comparative Example 5 with hexadecane;

[0040] Figure 5 This is a graph showing the effect of the superhydrophobic-oleophobic layer loading on the sweat conduction of Janus fabric;

[0041] in, Figure 5 a to Figure 5 c respectively super hydrophobic-oleophobic layer loading 0.04 g / m 2 , 0.24g / m 2 and 0.40g / m 2 ;

[0042] Figure 6 This is the result diagram of the effect of the superhydrophobic-oleophobic layer loading on the liquid moisture management performance of Janus fabric;

[0043] in, Figure 6 a is the cumulative one-way water transfer index; Figure 6 b is the infiltration time; Figure 6 c is the water absorption rate; Figure 6 d is the maximum infiltration radius; Figure 6 e is the liquid water diffusion rate; in the test, the upper surface is a superhydrophobic-oleophobic layer, the lower surface is a superhydrophobic-oleophobic / superhydrophilic-oleophobic layer, and the pH value of the test liquid is 5;

[0044] Figure 7 The graph shows the change of contact angle, water content and water evaporation rate on both sides of Janus fabric over time;

[0045] in, Figure 7 a is the change of water drop contact angle over time; Figure 7 b and Figure 7 c are water content curves of the test liquid droplets added on the super-hydrophobic-oleophobic side and the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side; Figure 7 d is the evaporation rate of water on the surface of different fabrics;

[0046] Figure 8 The results of the hydrophobic performance of Janus fabric on both sides to water of different pH values;

[0047] in, Figure 8 a is pH=7, Figure 8 b is pH = 10;

[0048] Fig. 9 The curve of the water drop contact angle change with time and the water content diagram on both sides of the Janus fabric;

[0049] in, Fig. 9 a is the curve of water drop contact angle changing with time; Fig. 9 b and Fig. 9 c are water content curves of water droplets added on the superhydrophobic-oleophobic side and the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, respectively;

[0050] Fig.10 This is the test result of the waterproof performance of Janus fabric;

[0051] in Fig.10 a is a diagram showing the state of the fabric being completely immersed in water and then taken out; Fig.10 b is the maximum water column height that the superhydrophobic-oleophobic / superhydrophilic-oleophobic side of the Janus fabric can withstand;

[0052] Fig.11 A schematic diagram of the one-way sweat conduction and waterproof mechanism of the Janus fabric provided in an embodiment of the present invention;

[0053] in, Fig.11 a is a schematic diagram of the unidirectional sweat conduction mechanism; Fig.11 b is a schematic diagram of waterproof mechanism;

[0054] Fig.12 A diagram showing the moisture permeability of the Janus fabric provided by an embodiment of the present invention;

[0055] Fig.13 A graph showing the self-cleaning performance of the Janus fabric provided by an embodiment of the present invention;

[0056] in, Fig.13 a is a process diagram of washing dust on the surface of fabric with deionized water; Fig.13 b and Fig.13 c are the optical images and contact angle diagrams of water and various oil droplets on the fabric surface; in the test, the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is used as the test surface. DETAILED DESCRIPTION

[0057] The following is a description of the embodiments of the present invention. Figures 1 to 13, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The U-side in the accompanying drawings of the embodiments of the present invention refers to the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, and the superhydrophobic-oleophobic / superhydrophilic-oleophobic side in the embodiments of the present invention specifically refers to the surface of the Janus fabric synthesized by the present invention on the side not provided with a superhydrophobic-oleophobic layer, that is, only the surface of the side provided with a pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer; and the S-side refers to the superhydrophobic-oleophobic side, specifically refers to the surface of the Janus fabric synthesized by the present invention on the side provided with a superhydrophobic-oleophobic layer.

[0059] Example 1

[0060] The present invention provides a pH-responsive, waterproof, oil-proof, and one-way perspiration-conducting Janus fabric, comprising a substrate, a pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer disposed on the outer surface of the substrate, and a superhydrophobic-oleophobic layer disposed on the side of the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer away from the substrate. In the present invention, the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer is 0.24 g / cm 2 .

[0061] In the embodiment of the present invention, the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer is composed of the following components:

[0062] pH responsive monomer, oleophobic monomer, photoinitiator and cross-linking agent, wherein the molar ratio of pH responsive monomer to oleophobic monomer is 6:3, the molar ratio of pH responsive monomer to cross-linking agent is 60:1, and the mass of photoinitiator is 3wt% of the mass of pH responsive monomer.

[0063] The pH responsive monomer in the present invention is any one or more of acrylamide, 2-vinylpyridine, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and diethylaminoethyl acrylate;

[0064] The oleophobic monomers in the present invention are any one or more of 2-(perfluorodecyl)ethyl methacrylate, 1H,1H-perfluoro-n-decyl methacrylate, 2-(perfluorooctyl)ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, perfluorobutylethylene, perfluorohexylethylene, and perfluorodecylethylene;

[0065] The photoinitiator in the present invention is any one or more of 2-hydroxy-2-methylpropiophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a,a,-dimethylbenzil ketal, benzophenone, 1-hydroxycyclohexyl benzophenone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;

[0066] The crosslinking agent in the present invention is any one or more of polyethylene glycol diacrylate, N-carboxyethyl acrylamide, N,N-methylenebisacrylamide, methacryloxy cage silsesquioxane, and 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate;

[0067] Specifically, the pH-responsive monomer, oleophobic monomer, photoinitiator and crosslinker in the embodiment of the present invention are preferably 2-vinylpyridine (2-VP), 2-(perfluorohexyl)ethyl methacrylate (TFOA), 2-hydroxy-2-methylpropiophenone (HMMP) and N,N-methylenebisacrylamide (BIS), respectively.

[0068] like Figure 1 As shown, the embodiment of the present invention also provides a method for preparing the above-mentioned pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric, which specifically includes the following steps:

[0069] S1. Immerse the cleaned 10cm*10cm polyester fabric in the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic modified solution for 10 minutes, then take out the polyester fabric to remove the excess solution, and place the polyester fabric in a UV curing box for 30 minutes at an irradiation intensity of 70W / cm 2 , the wavelength of ultraviolet light is 365nm, polymerization and cross-linking reactions occur, and after the reaction is completed, a pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer is formed on the outer surface of the polyester fabric;

[0070] In the embodiment of the present invention, the super hydrophobic-oleophobic / super hydrophilic-oleophobic modified solution is prepared by the following method:

[0071] (1) 2-vinylpyridine (2-VP), 2-(perfluorohexyl)ethyl methacrylate (TFOA), 2-hydroxy-2-methylpropiophenone (HMMP) and N,N-methylenebisacrylamide (BIS) were mixed and stirred at 25° C. for 10 min to obtain a mixed solution;

[0072] (2) mixing the mixed solution obtained in (1) with acetone in a volume ratio of 1:3, and stirring at 25° C. for 10 min to obtain a super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modified solution;

[0073] The molar ratio of 2-VP to TFOA is 6:3, the molar ratio of 2-VP to BIS is 60:1, and the mass of HMMP is 3 wt % of the mass of 2-VP.

[0074] S2, using an LPH-50 spray gun, at a pressure of 0.1 MPa, spray the super-hydrophobic-oleophobic modified solution on the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer obtained in step S1 on the side away from the polyester fabric. After spraying, place the polyester fabric in a UV curing box with the sprayed side facing up and irradiate for 30 minutes at an irradiation intensity of 70 W / cm 2 The ultraviolet light wavelength is 365nm, and polymerization and cross-linking reactions occur. After the reaction is completed, a super hydrophobic-oleophobic layer is formed on one side of the pH-responsive super hydrophobic-oleophobic / super hydrophilic-oleophobic layer. The loading amount of the super hydrophobic-oleophobic layer on the pH-responsive super hydrophobic-oleophobic / super hydrophilic-oleophobic layer is 0.24g / cm 2 , that is, the Janus fabric is obtained.

[0075] In the embodiment of the present invention, the super hydrophobic-oleophobic modified solution is prepared by the following method:

[0076] TFOA, HMPP, methacryloxy cage silsesquioxane (MA-POSS) and acetone were mixed, and the volume ratio of the total volume of TFOA, HMPP and methacryloxy cage silsesquioxane (MA-POSS) to acetone was 1:3; and stirred at room temperature for 10 minutes to obtain a uniform superhydrophobic-oleophobic modified solution;

[0077] The mass ratio of TFOA to MA-POSS is 200:1, and the mass of HMPP is 5 wt % of the total mass of TFOA and MA-POSS.

[0078] Example 2

[0079] The embodiment of the present invention provides a pH-responsive waterproof and oil-proof Janus fabric with one-way sweat conduction. The structure and preparation method of the Janus fabric provided in the embodiment of the present invention are the same as the structure and preparation method of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in the embodiment of the present invention is 0.08 g / cm 2 .

[0080] Example 3

[0081] The embodiment of the present invention provides a pH-responsive waterproof and oil-proof Janus fabric with one-way sweat conduction. The structure and preparation method of the Janus fabric provided in the embodiment of the present invention are the same as the structure and preparation method of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in the embodiment of the present invention is 0.16 g / cm 2 .

[0082] Example 4

[0083] The embodiment of the present invention provides a pH-responsive waterproof and oil-proof Janus fabric with one-way sweat conduction. The structure and preparation method of the Janus fabric provided in the embodiment of the present invention are the same as those of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in the embodiment of the present invention is 0.30 g / cm 2 .

[0084] Example 5

[0085] The embodiment of the present invention provides a pH-responsive waterproof and oil-proof Janus fabric with one-way sweat conduction. The structure and preparation method of the Janus fabric provided in the embodiment of the present invention are the same as the structure and preparation method of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in the embodiment of the present invention is 0.05 g / cm 2 .

[0086] Example 6

[0087] The embodiment of the present invention provides a pH-responsive waterproof and oil-proof, unidirectional sweat-conducting Janus fabric. The structure and preparation method of the Janus fabric provided in the embodiment of the present invention are the same as the structure and preparation method of the Janus fabric provided in Example 1, except that the molar ratio of 2-VP and TFOA in the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modified solution in the embodiment of the present invention is 6:1, the molar ratio of 2-VP and BIS is 5:1, and the mass of HMMP is 0.5wt% of the mass of 2-VP; and the mass ratio of TFOA and MA-POSS in the super-hydrophobic-oleophobic modified solution in the embodiment of the present invention is 100:1, and the mass of HMPP is 0.5wt% of the total mass of TFOA and MA-POSS;

[0088] In step S1 and step S2 of the preparation method of the embodiment of the present invention, the irradiation intensity of the ultraviolet light is 5W / cm 2 , the illumination time is 150min.

[0089] Example 7

[0090] The embodiment of the present invention provides a pH-responsive waterproof and oil-proof, unidirectional sweat-conducting Janus fabric. The structure and preparation method of the Janus fabric provided in the embodiment of the present invention are the same as the structure and preparation method of the Janus fabric provided in Example 1, except that the molar ratio of 2-VP and TFOA in the superhydrophobic-oleophobic / superhydrophilic-oleophobic modified solution in the embodiment of the present invention is 6:12, the molar ratio of 2-VP and BIS is 200:1, and the mass of HMMP is 10wt% of the mass of 2-VP; and the mass ratio of TFOA and MA-POSS in the superhydrophobic-oleophobic modified solution in the embodiment of the present invention is 10:1, and the mass of HMPP is 10wt% of the total mass of TFOA and MA-POSS.

[0091] In step S1 and step S2 of the preparation method of the embodiment of the present invention, the irradiation intensity of the ultraviolet light is 120W / cm 2 , the illumination time is 10min.

[0092] Comparative Example 1

[0093] This comparative example provides a Janus fabric. The structure and preparation method of the Janus fabric provided in this comparative example are the same as those of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in this comparative example is 0.04 g / cm 2 .

[0094] Comparative Example 2

[0095] This comparative example provides a Janus fabric. The structure and preparation method of the Janus fabric provided in this comparative example are the same as those of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in this comparative example is 0.40 g / cm 2 .

[0096] Comparative Example 3

[0097] This comparative example provides a Janus fabric. The structure and preparation method of the Janus fabric provided in this comparative example are the same as those of the Janus fabric provided in Example 1, except that the loading amount of the superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer in this comparative example is 0.32 g / cm 2 .

[0098] Comparative Example 4

[0099] This comparative example provides a Janus fabric, which is prepared by only treating the polyester fabric through step S1 of Example 1 without treating it through step S2.

[0100] Comparative Example 5

[0101] This comparative example provides a Janus fabric, which is prepared by simply spraying the polyester fabric with the super hydrophobic-oleophobic modification solution of step S2 of embodiment 1 without the treatment of step S1.

[0102] The performance of the pH-responsive waterproof and oil-proof, one-way perspiration-conducting Janus fabrics prepared in Examples 1-3 of the present invention and the Janus fabrics prepared in Comparative Examples 1-5 are compared and studied as follows:

[0103] 1. Morphology and surface chemical composition analysis

[0104] The morphology of both sides of the pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric prepared in Example 1 of the present invention and the morphology of the untreated polyester fabric were tested by SEM electron microscopy. The test results are as follows: Figure 2 As shown, through Figure 2 It can be seen from a that the fiber surface of the untreated polyester fabric is relatively smooth and has no coating coverage. Figure 2 b and Figure 2 c It can be seen that there is an obvious coating on the fiber surface of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side and the superhydrophobic-oleophobic side of the Janus fabric prepared in Example 1 of the present invention.

[0105] The surface chemical components of the two sides of the pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric prepared in Example 1 of the present invention and the untreated polyester fabric were analyzed by EDS. The results are as follows: Figure 3 As shown, through Figure 3 a It can be seen that the untreated polyester fabric is mainly composed of C and O elements; Figure 3 b It can be seen that new F and Si elements appear on the super-hydrophobic-oleophobic side of the Janus fabric prepared in Example 1 of the present invention, which belong to TFOA and MA-POSS in the super-hydrophobic-oleophobic layer, respectively. Figure 3 c It can be seen that new elements N and F also appear on the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side of the Janus fabric prepared in Example 1 of the present invention, where N is derived from 2-VP and BIS monomers, and F is derived from TFOA monomers. Figure 3From the distribution diagram of various elements on the fabric surface, it can be found that the super hydrophobic-oleophobic / super hydrophilic-oleophobic layer and the super hydrophobic-oleophobic layer on both sides of the Janus fabric prepared in Example 1 of the present invention are evenly covered on the fiber surface.

[0106] 2. Contact angle test and analysis of different pH solutions on polyester fabric surface

[0107] In order to verify the selective wettability of polyester fabric modified by superhydrophobic-oleophobic / superhydrophilic-oleophobic modification solution to water and sweat and the double repellency of polyester fabric modified by superhydrophobic-oleophobic modification solution, the wettability test of Janus fabrics prepared in Comparative Example 4 and Comparative Example 5 was carried out respectively. The test results are shown in FIG. Figure 4 As shown, through Figure 4 It can be seen from ac that the surface of the Janus fabric prepared in Comparative Example 4 is super hydrophilic to water with a pH value of 5, which is close to the pH value of sweat, and super hydrophobic to water droplets with a pH value of 7 and pH 10. The water droplets with a pH value of 5 can spread completely within 10 seconds, while the water droplets with a pH value of 7 and pH 10 still maintain a high contact angle within 600 seconds, showing long-lasting hydrophobicity. At the same time, the Janus fabric prepared in Comparative Example 4 shows stable oleophobic properties. Figure 4 It can be seen from Figure d that the contact angle of hexadecane on the surface of the Janus fabric prepared in Comparative Example 4 is about 136°. Figure 4 e and Figure 4 f It can be seen that after the liquid drops of water and hexadecane were left on the surface of the Janus fabric prepared in Comparative Example 5 for 30 minutes, their contact angles remained at about 156.2° and 135.5°, respectively, showing stable amphiphobic properties. The above results show that the preparation method of the present invention can obtain a reversibly switchable amphiphobic fabric that is responsive to an aqueous solution with a pH value close to that of sweat. Hydrophilic-oleophobic fabrics indicate that it is feasible to prepare new smart Janus polyester fabrics that are both waterproof and oil-proof and unidirectionally perspire-conducting.

[0108] 3. Effect of the loading amount of superhydrophobic-oleophobic layer on the pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer on the unidirectional sweat conduction performance of the fabric

[0109] The loading amount of the super hydrophobic-oleophobic layer in the present invention has an important influence on the conduction behavior of sweat on the fabric surface. The sweat conduction performance of the Janus fabric prepared in Example 1 of the present invention and the Janus fabric prepared in Comparative Examples 1 and 2 was tested. The test results are as follows: Figure 5 As shown, through Figure 5 It can be seen from a that when the loading amount of the super hydrophobic-oleophobic layer in Comparative Example 1 is too low (0.04 g / m 2), water droplets with a pH value close to that of sweat (pH = 5) can be conducted from the superhydrophobic-oleophobic side to the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, or vice versa, showing bidirectional conduction. Figure 5 b It can be seen that when the loading amount of the superhydrophobic-oleophobic layer increases to 0.24 g / m 2 , that is, the Janus fabric prepared in Example 1 of the present invention, the Janus fabric exhibits a fast one-way sweat conduction ability, and sweat can be quickly conducted from the superhydrophobic-oleophobic side to the superhydrophobic-oleophobic / superhydrophilic-oleophobic side within 7 seconds, while the sweat can only diffuse rapidly in the horizontal direction on the superhydrophobic-oleophobic / superhydrophilic-oleophobic side and cannot be transferred to the superhydrophobic-oleophobic side. Figure 5 c It can be seen that when the loading amount of the superhydrophobic-oleophobic layer is too large (0.40 g / m 2 ), that is, the Janus fabric prepared in Comparative Example 2, both sides of the fabric are hydrophobic surfaces, and sweat cannot be conducted to the back side of the fabric on both sides, showing that it is not conducted in both directions. Therefore, the loading amount of the super hydrophobic-oleophobic layer on the pH-responsive super hydrophobic-oleophobic / super hydrophilic-oleophobic layer is 0.24 g / m 2 The prepared Janus fabric of Example 1 of the present invention was used to conduct the following studies on its one-way sweat conduction, moisture absorption and quick drying, waterproofness, oil repellency, self-cleaning and moisture permeability properties.

[0110] According to the test standard AATCC195 on the dynamic transfer performance of liquid water of textiles, the Janus fabrics prepared in Examples 1-3 of the present invention and Comparative Examples 3 and 4 were tested by MMT for five indicators: (1) one-way water transfer index, (2) wetting time, (3) water absorption rate, (4) maximum wetting radius and (5) liquid water diffusion rate. The effect of the loading amount of the superhydrophobic-oleophobic layer on the dynamic transfer performance of sweat in the Janus fabric was further characterized. The results are as follows: Figure 6 shown.

[0111] (1) The cumulative one-way water transfer index (R) refers to the ability of liquid water to transfer from the soaked surface of the fabric to the permeable surface, that is, the ability to transfer from the upper surface to the lower surface, expressed as the ratio of the difference in water absorption on both sides of the fabric to the test time. Figure 6 It can be seen from a that when the super hydrophobic-oleophobic layer loading is 0 g / cm 2 When (Comparative Example 4), the Janus fabric exhibits a hydrophilic-oleophobic surface to the test solution (pH = 5), and the R value is 85%. As the loading amount of the super hydrophobic-oleophobic layer gradually increases to 0.24 g / cm 2(Examples 1-3), the R value increases from 85% to 815.5%, indicating that the directional water conduction ability of the fabric is continuously improved. According to the rating method for directional water conduction ability in the AATCC195 standard for the dynamic transfer performance of liquid water in textiles, when R>400%, the directional sweat conduction ability of the Janus fabric is rated as level five (optimal level), indicating that the directional sweat conduction ability is excellent. This shows that the Janus fabric prepared in Example 1 of the present invention can quickly conduct sweat from the superhydrophobic-oleophobic layer to the superhydrophobic-oleophobic / superhydrophilic-oleophobic layer, and has excellent directional sweat conduction performance. As the superhydrophobic-oleophobic layer loading further increases to 0.32g / cm 2 (Comparative Example 3), the R of the Janus fabric becomes -919.8%, indicating that at this time, the sweat on the surface of the Janus fabric cannot be directional conducted. This is because when the superhydrophobic-oleophobic modified solution is sprayed on one side of the Janus fabric, the superhydrophobic-oleophobic modified solution will penetrate into the superhydrophobic-oleophobic / superhydrophilic-oleophobic side on the back, so spraying an excessive amount of superhydrophobic-oleophobic modified solution will affect the wettability of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, making it impossible to respond to the test liquid, thereby making the surface maintain the amphiphobic wettability and unable to be transformed into a hydrophilic-oleophobic surface. At this time, both sides of the modified fabric are amphiphobic and do not have the ability to directional conduct sweat.

[0112] (2) Wetting time refers to the time from when the liquid contacts the fabric surface to when the fabric begins to absorb water. Figure 6 b It can be seen that when the loading amount of the super hydrophobic-oleophobic layer is 0-0.24 g / cm 2 When the superhydrophobic-oleophobic / superhydrophilic-oleophobic side of Janus fabric is wetted for a shorter time than the superhydrophobic-oleophobic side, this is because the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is stimulated by the test liquid with pH=5 from the superhydrophobic-oleophobic side, and the surface is transformed into hydrophilic-oleophobic, thereby generating capillary force, which can quickly absorb the droplets on the superhydrophobic-oleophobic side. 2 , the wetting time of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side of the Janus fabric is always greater than that of the superhydrophobic-oleophobic side, and the wetting time of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is 120s (test time). This is because the surface of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is covered by the superhydrophobic-oleophobic layer, and the surface wettability is amphiphobic to the test liquid, and the droplets on the upper surface cannot be conducted to the superhydrophobic-oleophobic / superhydrophilic-oleophobic side.

[0113] (3) Water absorption rate refers to the rate of increase in the amount of water absorbed by the fabric per unit time. Figure 6c It can be seen that with the increase in the loading amount of the superhydrophobic-oleophobic layer, the water absorption rate of the superhydrophobic-oleophobic side of the Janus fabric decreases from 55.6% to 15.8%, while the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is basically maintained at around 55.0%, maintaining almost the same water absorption rate as before the fabric modification, indicating that the fabric obtained by the preparation method of the embodiment of the present invention has typical Janus fabric characteristics.

[0114] (4) Maximum wetting radius (MWR) refers to the maximum radius of the wetting area during the test time. Figure 6 As shown in Figure d, with the increase of the loading amount of the superhydrophobic-oleophobic layer, the maximum wetting radius of the superhydrophobic-oleophobic side of the fabric gradually decreases, while the maximum wetting radius of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is basically maintained at about 25 mm, proving that the droplets can effectively pass through the superhydrophobic-oleophobic side to reach the superhydrophobic-oleophobic / superhydrophilic-oleophobic side and diffuse only on this side.

[0115] (5) Liquid water diffusion rate (SS) refers to the cumulative transfer rate of liquid water along the radial direction when the fabric surface is soaked and diffuses to the maximum soaking radius. Figure 6 As shown in Figure e, similar to the change in the maximum wetting radius of the fabric, with the increase in the loading amount of the superhydrophobic-oleophobic layer, the liquid water diffusion rate of the superhydrophobic-oleophobic side continues to decrease under the action of the increasing hydrophobic force, while the effective unilateral modification enables the superhydrophobic-oleophobic / superhydrophilic-oleophobic side to always maintain a good response wetting surface, which quickly transforms into a hydrophilic-oleophobic surface when it contacts the droplets, and quickly absorbs and transfers water under the action of capillary force.

[0116] 4. Study on the performance of single-direction sweat conduction

[0117] The contact angle, water content and water evaporation rate of both sides of the Janus fabric prepared in Example 1 of the present invention were characterized over time. The results are as follows: Figure 7 As shown. Figure 7 From the curve of the change of water contact angle over time on both sides of the Janus fabric in a, it can be seen that the contact angle of the water droplet with pH = 5 on the superhydrophobic-oleophobic side decreases from 123.2° to 0° within 10 seconds, while the water droplet on the superhydrophobic-oleophobic / superhydrophilic-oleophobic side decreases from 117.3° to 0° within a shorter time (8 seconds). Therefore, the two sides of the Janus fabric prepared in Example 1 of the present invention show different wetting behaviors to sweat.

[0118] like Figure 7 b and Figure 7As shown in Figure c, when the test liquid with a pH of 5 is dropped on the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, water is absorbed into the superhydrophobic-oleophobic / superhydrophilic-oleophobic layer under the action of capillary force, and when the water reaches the bottom of the Janus fabric, it is blocked and cannot penetrate due to the presence of the superhydrophobic-oleophobic layer. Therefore, during the entire test process, the water content of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is much higher than that of the superhydrophobic-oleophobic side, and the water content of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is stable at about 1500%, while the water content of the superhydrophobic-oleophobic side is only 600%. When the superhydrophobic-oleophobic side of the Janus fabric is facing upward, water droplets cannot spread on the superhydrophobic surface. Due to the existence of the capillary force of the underlying layer, the water droplets quickly penetrate into the superhydrophobic-oleophobic / superhydrophilic-oleophobic side. Therefore, within 120 seconds, the water content on the superhydrophobic-oleophobic side did not change significantly and remained at around 30%, while the water content on the superhydrophobic-oleophobic / superhydrophilic-oleophobic side increased from 0 to about 1200% in the first 50 seconds, and then gradually decreased to about 600%. The decrease in water content in this stage is caused by the fact that after the test liquid is conducted from the superhydrophobic-oleophobic side to the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, as the droplets accumulate rapidly, the droplets gradually detach from the fabric. In addition, when the super-hydrophobic-oleophobic side of the Janus fabric faces upward and the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side faces upward, the R values ​​of the Janus fabric are 815.5% and -1190.3%, respectively, and the evaluation grade of its one-way sweat conduction performance is level five (optimal level), indicating that the Janus fabric has excellent one-way sweat conduction performance. After the sweat is conducted to the outside of the fabric, only by evaporating quickly to keep the surface of the fabric dry can the one-way sweat conduction performance of the Janus fabric continue to function. Once the sweat does not evaporate in time, the outside of the fabric will be soaked, and the one-way sweat conduction function of the Janus fabric will be lost. At the same time, for comparison, the water evaporation rate on the surface of the unmodified polyester fabric, the Janus fabric of Example 1 of the present invention, the pH-responsive polyester fabric (Comparative Example 4), and the double-hydrophobic polyester fabric (Comparative Example 5) was tested, and the results are as follows: Figure 7 d, through Figure 7 It can be seen that it takes only 15 min for Janus fabric to completely evaporate 0.2 g of water on the fabric surface, while it takes 35 min, 90 min and 210 min for pH-responsive polyester fabric, unmodified polyester fabric and double-sparse polyester fabric, respectively. Therefore, the water evaporation rate of the Janus fabric of Example 1 of the present invention is much higher than that of other fabrics. Compared with the hygroscopic and quick-drying Janus fabrics reported in recent years, the water evaporation rate of the Janus fabric prepared in Example 1 of the present invention is significantly faster, indicating that it has great advantages as a hygroscopic and quick-drying textile.

[0119] 5. Waterproof performance research

[0120] The waterproof performance test results of the Janus fabric prepared in Example 1 of the present invention are as follows: Figure 8 As shown, through Figure 8 It can be seen that for water with pH = 7 and pH = 10, both the pH response side and the double-repellent side of the Janus fabric prepared in Example 1 of the present invention show good water repellency. Within 120 seconds, the water droplets on both sides of the Janus fabric remain hydrophobic.

[0121] pass Fig. 9 It can be seen from a that on the super-hydrophobic-oleophobic side, the water contact angle of the water droplet barely changes within 120 seconds and stabilizes at around 141.2°. The water contact angle on the pH-responsive side also stabilizes at around 118°. Fig. 9 b and Fig. 9 From the MMT test results of c, it can be seen that no matter water droplets (pH=7) are dripped on the superhydrophobic-oleophobic side or the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, a large amount of water can only be detected on the dripping side, but no water can be detected at the bottom of the fabric, and the water content at the bottom is 0. The above results also prove that the Janus fabric prepared in Example 1 of the present invention has excellent hydrophobicity.

[0122] In order to further study the waterproofness of the Janus fabric prepared in Example 1 of the present invention, the Janus fabric prepared in Example 1 of the present invention was immersed in water and taken out after a few seconds to observe the wetting condition of the fabric surface. Fig.10 As can be seen in a, the surface of the Janus fabric taken out of the water is not wetted by water and remains dry. Fig.10 b It can be seen that the maximum water column height that the Janus fabric can withstand is about 120 mm. The above results show that the Janus fabric prepared in Example 1 of the present invention can meet the requirements of waterproof fabrics in daily life and has practicality.

[0123] 6. Research on the mechanism of one-way sweat conduction and waterproof performance

[0124] The one-way sweat conduction and waterproof mechanism of the Janus fabric prepared in Example 1 of the present invention is as follows: Fig.11 As shown, through Fig.11It can be seen from figure that when the superhydrophobic-oleophobic side of the fabric is used as the inner side, the sweat generated by the skin (water with pH = 5) is subjected to two opposite forces, the hydrophobic force (HF) and the liquid pressure (LP) from the superhydrophobic-oleophobic side. When the liquid pressure is large enough (for a droplet with a volume of 5 μL), the LP can overcome the HF from the superhydrophobic-oleophobic side and reach the superhydrophobic-oleophobic / superhydrophilic-oleophobic side of the underlying layer. When the sweat reaches the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, the P2VP chain segments in the coating on this side are rapidly transformed from a dual-hydrophobic surface to a hydrophilic-oleophobic surface under the stimulation of acidic sweat. The sweat will immediately be subjected to the capillary force (CF) from the hydrophilic-oleophobic side, thereby quickly conducting the sweat from the superhydrophobic-oleophobic side on the inside of the fabric to the outside, and rapidly spreading on the hydrophilic-oleophobic outside. However, when sweat contacts the fabric from the superhydrophobic-oleophobic / superhydrophilic-oleophobic side, the superhydrophobic-oleophobic / superhydrophilic-oleophobic side quickly transforms into a hydrophilic-oleophobic surface, and the sweat is affected by the capillary force from the hydrophilic-oleophobic surface of the superhydrophobic-oleophobic / superhydrophilic-oleophobic side and its own liquid pressure, and diffuses on the hydrophilic-oleophobic side. Then, when the sweat contacts the superhydrophobic-oleophobic side, it is affected by the hydrophobic force from the superhydrophobic-oleophobic side. At this time, the liquid pressure of the superhydrophobic-oleophobic side can be ignored, and the water is finally blocked by the superhydrophobic-oleophobic side. Therefore, when the superhydrophobic-oleophobic side of the Janus fabric is used as the inner side of the skin and the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is used as the outer side of the fabric, the one-way sweat-conducting function of sweat from the skin-contacting side to the outer side can be effectively achieved.

[0125] pass Fig.11 b It can be seen that when water with pH = 7 contacts the super-hydrophobic-oleophobic side of the Janus fabric, the water droplet is affected by the hydrophobic force from the super-hydrophobic-oleophobic side and the pressure of its own liquid. At the same time, since the pH response side of the Janus fabric also behaves as hydrophobic or super-hydrophobic to water with pH = 7, the water droplet is blocked on the double-repellent side and maintains a high hydrophobicity, and cannot achieve water conduction. Similarly, when the water droplet with pH = 7 first contacts the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side of the Janus fabric, the surface of the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side shows double-repellent wettability. Since the other side is double-repellent, the water droplet cannot overcome the hydrophobic force from the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side under the action of liquid pressure to achieve water conduction, so the water droplet stays on the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic side and maintains a high contact angle. Therefore, the Janus fabric prepared in Example 1 of the present invention has waterproof function on both sides.

[0126] From the above, it can be seen that when the superhydrophobic-oleophobic side of the Janus fabric prepared in Example 1 of the present invention is used as the inner side of the skin and the superhydrophobic-oleophobic / superhydrophilic-oleophobic side is used as the outer side of the fabric, not only can the one-way conduction of sweat be achieved, but it also has a good waterproof function.

[0127] 7. Research on moisture permeability

[0128] The Janus fabric prepared in Example 1 of the present invention was fixed between two beakers (the beaker at the bottom contained hot water), and the moisture permeability of the Janus fabric was qualitatively analyzed. The results are as follows: Fig.12 As shown, through Fig.12 It can be seen that water vapor quickly diffuses from the bottom beaker through the fabric to the top beaker, and condenses into water droplets on the top beaker wall, indicating that the Janus fabric prepared in Example 1 of the present invention has good moisture permeability and can provide protection for the wearing comfort of clothing.

[0129] The Janus fabric prepared in Example 1 of the present invention is compared with the currently reported smart response Janus fabric or membrane material. Since the current common or smart response Janus fabric does not utilize the hydrophilic-oleophobic surface, the present invention is only compared with the only two smart response Janus materials currently available. The results are shown in Table 1 below. Similar to the method for preparing Janus fabric in Example 1 of the present invention, the two existing smart response Janus documents also use unilateral modification to obtain an asymmetric wetting surface, but the steps are more complicated; its stimulus response also comes from the protonation and deprotonation reaction of the N or -COOH group in the monomer. However, its response type is a non-in-situ response, and the wettability conversion must be achieved after acid or alkali immersion. The wetted surface after the response has no selective wettability to water of different pH values, and cannot intelligently distinguish between sweat and ordinary water, and cannot simultaneously have unilateral sweat-guiding and waterproof functions. In addition, since the materials in the literature can only achieve the transition between superhydrophilic-superoleophilic and hydrophobic-superoleophilic after pH response, the Janus fabric has superhydrophilic-superoleophilic and hydrophobic-superoleophilic surfaces on both sides, respectively, and the Janus fabric only has a simple unidirectional water conduction performance and does not have waterproofness. At the same time, since both sides of the Janus fabric are superoleophilic surfaces, the fabric does not have an oil-proof function. The Janus fabric prepared in Example 1 of the present invention can achieve unidirectional sweat conduction and waterproof functions, and has a good oil-proof function, and has a unique advantage in the field of multifunctional textiles.

[0130] Table 1 Comparison of the Janus fabric prepared in Example 1 of the present invention with the reported smart response Janus fabric

[0131]

[0132]

[0133] Note: Dimethylaminoethyl methacrylate (DMAEMA), cage-shaped octavinylsilsesquioxane (OVi-POSS), 1,3,5,7-tetramethylvinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D4 vi), styrene (S), polystyrene (PS), carbon nanotubes (CNTs), polyvinylidene fluoride (PVDF)

[0134] 8. Research on self-cleaning performance

[0135] The self-cleaning performance test results of the Janus fabric prepared in Example 1 of the present invention are as follows: Fig.13 As shown, through Fig.13 As shown in a, the water droplets in the straw impact the dust on the surface of the Janus fabric (superhydrophobic-oleophobic / superhydrophilic-oleophobic side), and the water droplets easily roll off the surface of the fabric and take away the dust on the surface, finally obtaining a clean surface. Therefore, the Janus fabric of Example 1 of the present invention exhibits good self-cleaning performance. Fig.13 b It can be seen that the droplet remains approximately spherical on the fabric surface and does not penetrate the fabric. Fig.13 The contact angle test results of c show that the contact angles of water, tea, coffee, milk, motor oil, hexadecane, soybean oil and diesel on the superhydrophobic-oleophobic / superhydrophilic-oleophobic side of the Janus fabric are 140.2°, 137.7°, 142.3°, 131.5°, 135°, 137.3°, 145.1° and 132.5°, respectively, indicating that the surface of the Janus fabric prepared in Example 1 of the present invention has strong liquid repellency and can effectively prevent droplets that are often contacted in daily life.

[0136] In summary, the Janus fabric prepared in the embodiment of the present invention exhibits a unidirectional sweat-conducting characteristic for water with a pH value of 5 simulating sweat, and the unidirectional water transfer index is 815.5% (optimal level), and has good oil resistance, and the contact angle of the Janus fabric to hexadecane is 136.1°. It can be used for unidirectional sweat-conducting fabrics with oil resistance requirements; at the same time, the Janus fabric prepared in the embodiment of the present invention exhibits amphiphobicity on both sides to water droplets with a pH value of 7, and water droplets cannot be conducted from one side of the Janus fabric to the other side. The maximum water column height that the fabric surface can withstand is about 120 mm, indicating that the Janus fabric has good water resistance to water with a pH value of 7. Moreover, the Janus fabric only needs 15 minutes to completely evaporate 0.2g of sweat on the fabric surface. Compared with the moisture-absorbing and quick-drying Janus fabric reported in recent years, it has a faster water evaporation rate and has great advantages in the application of moisture-absorbing and quick-drying textiles.

[0137] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A pH-responsive, waterproof, oil-proof, one-way sweat-conducting Janus fabric, characterized in that: The invention comprises a substrate, wherein a pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer is arranged on the outer surface of the substrate, and a super-hydrophobic-oleophobic layer is arranged on the surface of the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer on the side away from the substrate.

2. The pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 1, characterized in that: The loading amount of superhydrophobic-oleophobic layer on pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer is 0.05-0.30 g / cm 2 .

3. The pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 1, characterized in that: The pH-responsive superhydrophobic-oleophobic / superhydrophilic-oleophobic layer is composed of the following components: pH responsive monomer, oleophobic monomer, photoinitiator and crosslinking agent, wherein the molar ratio of pH responsive monomer to oleophobic monomer is 6:1-12, the molar ratio of pH responsive monomer to crosslinking agent is 5-200:1, and the mass of photoinitiator is 0.5-10wt% of the mass of pH responsive monomer.

4. A method for preparing a pH-responsive waterproof and oil-proof, one-way sweat-conducting Janus fabric, characterized in that: The following steps are involved: S1, immersing the substrate in a super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modification solution, causing polymerization and cross-linking reactions under ultraviolet light irradiation, and after the reaction, forming a pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer on the outer surface of the substrate; S2, spraying the super-hydrophobic-oleophobic modified solution on the surface of the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer obtained in step S1, which is away from the substrate, and causing polymerization and cross-linking reactions under ultraviolet light. After the reaction is completed, a super-hydrophobic-oleophobic layer is formed on one side of the pH-responsive super-hydrophobic-oleophobic / super-hydrophilic-oleophobic layer, thereby obtaining the pH-responsive Janus fabric.

5. The method for preparing the waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 4, characterized in that: In step S1, the super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modified solution is prepared by the following method: The pH-responsive monomer, the oleophobic monomer, the photoinitiator, the cross-linking agent and the organic solvent are uniformly mixed to obtain a super-hydrophobic-oleophobic / super-hydrophilic-oleophobic modified solution; The molar ratio of the pH responsive monomer to the oleophobic monomer is 6:1-12, the molar ratio of the pH responsive monomer to the crosslinking agent is 5-200:1, and the mass of the photoinitiator is 0.5-10wt% of the mass of the pH responsive monomer.

6. The method for preparing the waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 5, characterized in that: In step S2, the super-hydrophobic-oleophobic modified solution is prepared by the following method: The oleophobic monomer, the photoinitiator, the crosslinking agent and the organic solvent are uniformly mixed to obtain a super hydrophobic-oleophobic modified solution; The mass ratio of the oleophobic monomer to the crosslinking agent is 200-10:1, and the mass of the photoinitiator is 0.5-10wt% of the total mass of the oleophobic monomer and the crosslinking agent.

7. The method for preparing the waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 5, characterized in that: In step S1, the pH responsive monomer is any one or more of acrylamide, 2-vinylpyridine, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and diethylaminoethyl acrylate.

8. The method for preparing the waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 6, characterized in that: In step S1 and step S2, the oleophobic monomers are any one or more of 2-(perfluorodecyl)ethyl methacrylate, 1H,1H-perfluoro-n-decyl methacrylate, 2-(perfluorooctyl)ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, perfluorobutylethylene, perfluorohexylethylene, and perfluorodecylethylene.

9. The method for preparing the waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 6, characterized in that: In step S1 and step S2, the photoinitiator is any one or more of 2-hydroxy-2-methylpropiophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a,a,-dimethylbenzil ketal, benzophenone, 1-hydroxycyclohexyl benzophenone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; The crosslinking agents are any one or more of polyethylene glycol diacrylate, N-carboxyethyl acrylamide, N,N-methylenebisacrylamide, methacryloxy cage-type silsesquioxane, and 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate.

10. The method for preparing the waterproof and oil-proof, one-way sweat-conducting Janus fabric according to claim 4, characterized in that: In step S1 and step S2, the irradiation intensity of the ultraviolet light is 5-120W / cm 2 , the ultraviolet light wavelength is 365nm, and the illumination time is 10-150min.

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