Preparation method and application of bionic intelligent hydrophilic and hydrophobic fresh water collection fiber

Abstract

The invention discloses a preparation method and application of bionic intelligent hydrophilic and hydrophobic fresh water collection fibers, and belongs to the technical field of chemical bionics. The preparation device comprises a fibril fixing frame, a symmetrical hole channel square liquid tank, a camera obscura ultraviolet analyzer and a fiber receiver. The method comprises the following steps: firstly, fixing fibrils on a fibril fixing frame, enabling a prepared polymer mixed solution with the mass fraction of 9%-15% and the fibrils to pass through a symmetrical pore channel square liquid tank, pouring the polymer solution into the square liquid tank, pulling the fibrils at a constant speed to sequentially pass through the square liquid tank, and curing generated bead string fibers through an ultraviolet curing box, finally, fixing the bead string fiber on a fiber receiver, and freeze-drying the received bead string fiber to obtain the bionic intelligent fresh water collection fiber with the micro-nano pore channel structure. The preparation device is simple, the preparation method is simple, and the cost is extremely low; the surface of the fresh water collecting fiber is provided with a nano-scale interpenetrating network pore channel structure, so that the fresh water collecting fiber is easy to weave and has excellent stability, and rapid capture and collection of liquid drops are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical bionics, and specifically relates to a preparation method and application of a bionic intelligent affinity-repellent freshwater collection fiber. Background Art

[0002] Water is one of the most important natural resources in the world. According to the World Water Association, 2.2 billion people lack safe drinking water. In many remote arid and semi-arid areas where rainwater is scarce all year round, people collect fresh water by desalinating seawater, recycling wastewater after treatment, or extracting groundwater. However, the equipment required is generally large and energy-intensive, which limits the practical application of the above technologies in rural areas. Since arid areas such as islands, coastal deserts and mountainous areas are often subject to dense fog, and a large amount of atomized water is often produced in human life, it is very promising to alleviate the current situation of water shortage through the rational design of effective fog collectors.

[0003] Fog is an important form of moisture in the air. Even in arid deserts, fog contains sufficient moisture. Fog has always been considered an important potential source of fresh water. After decades of development, fog capture technology has become relatively mature. The appearance of the fog collector is a large mesh structure similar to a boundary net. When capturing fog droplets, the fog droplets flow into the collector below. The amount of fog collected depends on the size of the net, the size of the holes, and its chemical coating. Passive fog collectors can collect 2% to 10% of the moisture in the fog. The water collected by this method is safer than groundwater, has no energy requirements, is low-cost, and parts are easy to purchase.

[0004] A long time ago, the Canadian charity FogQuest set up more than 30 large fog collectors in Guatemala, providing 6,000L of fresh water every day to a village at an altitude of 3,300m; in Ethiopia, it provided drinking water to 700 monks and nuns living on the edge of an extinct volcano and the agricultural community that supports the monastery. The Peruvian government set up fog water collection stations made of nylon nets near the Pacific Ocean, and the water collected flows into the water tank along the net. The amount of fog water collected is converted into rainfall of 296 mm and 165.1 mm respectively. Despite this, the water collection efficiency still needs to be improved.

[0005] After a long period of evolution, organisms in nature have acquired the ability to survive in extremely water-scarce environments. Therefore, the bionic preparation of new water-collecting materials with low energy consumption, high efficiency and environmental protection is expected to become a new way to solve the problem of water scarcity. Summary of the invention

[0006] In view of the defects of the prior art in that the water collection efficiency is low, the demand for water in water-scarce areas cannot be met, the cost is high and it is not environmentally friendly, the present invention proposes a preparation method and application of a bionic intelligent affinity-repellent alternating freshwater collection fiber, which imitates the water collection process of spider silk, can efficiently collect tiny water droplets in the air, realize the directional transmission and collection of droplets, and the application of the freshwater collection fiber can be used for demisting.

[0007] The present invention provides a method for preparing a bionic intelligent hydrophilic freshwater collection fiber, and the specific steps are as follows:

[0008] Step 1, pre-treating the fiber;

[0009] The fiber is selected from the cuprammonium fiber among the man-made fibers, and the average diameter of the cuprammonium fiber is preferably 30 to 100 μm, and more preferably 50 μm;

[0010] The specific pretreatment process is as follows: first, the fiber is cleaned with a detergent to remove dust on the surface; then the fiber is immersed in acetone, ethanol and hydrochloric acid solutions in sequence to remove impurities and oxides on the fiber surface; finally, the fiber is cleaned with water, and after drying, the fiber is etched to increase the roughness of the fiber and enhance its hydrophilicity.

[0011] The etching process is specifically as follows: 4 parts by weight of sodium hydroxide is dissolved in 100 parts by weight of water, and stirred to dissolve; 1.14 parts by weight of ammonium persulfate is dissolved in 100 parts by weight of water, and stirred to dissolve; the two are mixed evenly to obtain a clear and transparent solution, the fiber is placed in the solution, and etched for 30 minutes to obtain an etched fiber.

[0012] Step 2, fixing the pretreated fiber on the experimental device;

[0013] The experimental device includes a raw fiber fixing bracket, a square liquid tank with symmetrical channels, a dark box ultraviolet analyzer and a fiber receiver.

[0014] The rotating shaft of the original fiber fixing support and the rotating shaft of the fiber receiver have the same diameter and are located at the same horizontal position.

[0015] The square liquid tank with symmetrical channels is used to hold the solution. There is a pair of symmetrical small holes with a diameter of 0.5 to 1 mm on the left and right sides. The center of the channel is located on the same straight line, and the fiber passes horizontally through the small holes on the left and right sides.

[0016] The darkbox UV analyzer is composed of an observation window, a shooting window, a darkbox, movable operating ports on the left and right sides, and a control panel. The observation window filters out ultraviolet rays for easy observation, and the shooting window is used for camera shooting. The darkbox has a built-in UV lamp, and the angle and performance can be adjusted at will to allow the light source to illuminate any position in the darkbox. The movable operating ports on the left and right sides are symmetrical opening and closing doors to ensure that the fiber is placed horizontally in the darkbox. There are three controllable wavelength switches on the surface of the control panel.

[0017] One end of the fiber is wound and fixed on the rotating shaft of the original fiber fixing bracket, and the other end passes through the symmetrical channel square liquid tank and the dark box UV analyzer in sequence, and finally is wound and fixed on the rotating shaft of the fiber receiver. The fiber is in a horizontal state as a whole.

[0018] Step 3, adding polymer a and polymer b to an organic solvent at the same time, adding 0.3 parts by weight of N,N-methylenebisacrylamide and two drops of 2-hydroxy-2-methylpropiophenone 1173 to the organic solvent, stirring for more than 24 hours, and obtaining a polymer solution with a polymer mass fraction of 8 to 12%;

[0019] The polymer a is any one of polyvinylidene fluoride (PVDF) or polymethyl methacrylate (PMMA); the polymer b is any one of polyvinylidene alcohol (PVA) or polyisopropylacrylamide (PNIPAM);

[0020] The ratio of polymer a to polymer b is 7:1-5;

[0021] The organic solvent is any one of N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA).

[0022] The polymer solution is a viscous, clear and transparent solution;

[0023] Step 4: Pour the polymer solution into the symmetrical channel square liquid tank in the experimental device, soak the fiber with the liquid surface, and then pull it at a speed of 100-150 mm / min. After the pulling is completed, the fiber moves out of the symmetrical channel square liquid tank, and the polymer forms beads on the fiber surface.

[0024] Step 5: The beads on the fiber surface are cured and dried in a dark box UV analyzer to obtain beaded fibers, which are collected on the rotating shaft of the fiber receiver.

[0025] Drying conditions in the dark box UV analyzer: UV wavelength 365nm, humidity 40% to 60%, temperature 23°C, drying time 1.5 to 15min.

[0026] Step six, freeze-drying the beaded fibers to obtain bionic freshwater collection fibers with a nanoporous structure.

[0027] The prepared beaded fiber was immersed in deionized water for 12 to 24 hours, taken out and frozen with liquid nitrogen, and then freeze-dried with a freeze dryer to obtain a bionic freshwater collection fiber with a nanoporous structure.

[0028] The prepared bionic freshwater collection fiber imitates the water collection process of spider silk. The beads on the fiber are distributed at intervals. Each bead is superhydrophobic, and the beads are hydrophilic. The height of each bead is 200-300μm, the length is 400-500μm, the surface of the bead is a nanoporous structure of 10-50nm, and the spacing between two beads is 900-1000μm. The height, width and spacing of the beads are affected by the polymer concentration and the pulling speed. The greater the concentration of the polymer solution and the pulling speed, the greater the height and length of the beads, and the greater the spacing; the smaller the concentration of the polymer solution and the pulling speed, the smaller the height and length of the beads, and the smaller the spacing.

[0029] A bionic intelligent hydrophilic and hydrophobic freshwater collection fiber net woven by the present invention is placed in a foggy environment. After the fiber net is moistened by the fog, water droplets will condense at the bead knots and the weaving junctions. When the water droplets reach the maximum critical volume, they automatically fall off under the action of gravity, and are transmitted and collected to achieve the purpose of water collection.

[0030] The present invention has the advantages that:

[0031] 1. The present invention provides a method for preparing a bionic intelligent affinity-repellent freshwater collection fiber. The experimental device can be carried at will, the preparation process is one-step, and the operability is strong. Environmentally friendly materials and processes are used to avoid high energy consumption and environmental pollution, and meet the requirements of sustainable development. The preparation materials are easy to obtain and have good stability, and are durable and not easy to degrade.

[0032] 2. The present invention provides a method for preparing a bionic intelligent hydrophilic and hydrophobic freshwater collection fiber. The polymer mixed solution used has the excellent properties of both polymers, has enhanced adhesion, and has better hydrophilicity and chemical stability.

[0033] 3. The bionic intelligent hydrophilic freshwater collection fiber prepared by the present invention has nanoscale pores distributed on the beaded surface, which increases the collision probability and spreading speed of air droplets and materials, and improves the water collection rate.

[0034] 4. The bionic intelligent affinity-repellent freshwater collection fiber prepared by the present invention has high practicality, is easy to bend and weave, and can be woven into two-dimensional and three-dimensional structures according to needs. It has high practicality and durability.

[0035] 5. The fiber net prepared by the bionic intelligent affinity-repellent alternating fresh water collection fiber of the present invention collects water droplets in the fog in foggy areas, thereby obtaining usable fresh water. It can also be used to dispel dense fog around airports and highways, while achieving the effect of water collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1It is a schematic diagram of an experimental device in a method for preparing a bionic intelligent affinity-repellency alternating freshwater collection fiber of the present invention;

[0037] Figure 2 This is a scanning electron microscope image of the bionic intelligent hydrophilic and hydrophobic freshwater collection fiber prepared by the present invention; wherein, Figure 2 a is the structure diagram of beaded fiber. Figure 2 b is the micropore structure diagram of the middle surface of the bead knot. Figure 2 c is an enlarged view of the micropores on the middle surface of the bead knot;

[0038] Figure 3 This is a schematic diagram of the bead size of the bionic intelligent hydrophilic freshwater collection fiber prepared by the present invention; Figure 3 a is the distance between beads, Figure 3 b is the height of the bead knot, Figure 3 c is the width of the bead knot;

[0039] Figure 4 This is an optical schematic diagram of water transmission during the water collection process of the bionic fresh water collection fiber prepared in Example 2 of the present invention;

[0040] Figure 5 This is an optical schematic magnified diagram of the water transmission effect of the bionic fresh water collection fiber prepared in Example 2 of the present invention during the water collection process;

[0041] Figure 6 A schematic structural diagram of a bionic intelligent hydrophilic freshwater collection fiber net provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] The invention proposes a method for preparing a bionic intelligent affinity-repellent freshwater collection fiber, combined with Figure 1 As shown in the device diagram, it specifically includes the following steps:

[0044] Step 1: Pre-treat the fiber and then fix the fiber on the experimental device

[0045] The experimental device is shown in the figure Figure 1 As shown, it is composed of a raw fiber fixing bracket 1, a symmetrical channel square liquid tank 2, a dark box ultraviolet analyzer 3 and a fiber receiver 4. One end of the fiber 5 is fixed on the raw fiber fixing bracket 1, and the other end of the fiber 5 passes through the symmetrical channel square liquid tank 2 and the dark box ultraviolet analyzer 3 in sequence, and is finally fixed on the fiber receiver 5, and the fiber 5 is in a horizontal state as a whole.

[0046] The rotating shaft of the original fiber fixing support and the rotating shaft of the fiber receiver have the same diameter and are located at the same horizontal position.

[0047] The square liquid tank with symmetrical channels is used to hold the solution. There is a pair of symmetrical small holes with a diameter of 0.5 to 1 mm on the left and right sides. The center of the channel is located on the same straight line, and the fiber passes horizontally through the small holes on the left and right sides.

[0048] The darkbox UV analyzer is composed of an observation window, a shooting window, a darkbox, movable operating ports on the left and right sides, and a control panel. The observation window filters out ultraviolet rays for easy observation, and the shooting window is used for camera shooting. The darkbox has a built-in UV lamp, and the angle and performance can be adjusted at will to allow the light source to illuminate any position in the darkbox. The movable operating ports on the left and right sides are symmetrical opening and closing doors to ensure that the fiber is placed horizontally in the darkbox. There are three controllable wavelength switches on the surface of the control panel for controlling the ultraviolet wavelength of the UV lamp.

[0049] The fiber 5 is a man-made fiber, preferably cuprammonium fiber, and the average diameter of the cuprammonium fiber is preferably 30 to 100 μm, more preferably 50 μm.

[0050] Step 2: Prepare a polymer mixed solution with a mass fraction of 8-12%

[0051] Add polymer a solution and polymer b into an organic solvent, the two polymers will be connected together through an oil bath reaction, and stir overnight for more than 24 hours to obtain a clear and transparent solution; the polymer a is any one of polyvinylidene fluoride (PVDF) or polymethyl methacrylate (PMMA); polymer b is any one of polyvinylidene alcohol PVA and polyisopropylacrylamide PNIPAM; the organic solvent is any one of N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA).

[0052] The ratio of polymer a to polymer b is 7:1-5.

[0053] Step 3: Pull to create a bead knot

[0054] The polymer solution is poured into a square liquid tank with symmetrical channels. The liquid surface is immersed in the fiber, and then it is pulled at a speed of 100-150 mm / min. After the pulling is completed, the surface is first covered with polymer fibers, and then beads are produced.

[0055] Step 4: The beads on the fiber surface are cured and dried in a dark box UV analyzer to obtain beaded fibers, which are collected on the rotating shaft of the fiber receiver.

[0056] Step 5: Freeze drying of beads:

[0057] The prepared beaded fibers were immersed in deionized water overnight, frozen with liquid nitrogen the next day, and then freeze-dried with a freeze dryer to obtain bionic freshwater collection fibers with a nanopore structure on the surface.

[0058] The height of the beaded fibers of the intelligent bionic hydrophilic freshwater collection fiber prepared by the method proposed in the present invention is 200-300 μm, the length of the beaded fibers is 400-500 μm, and the spacing between the beaded fibers is 900-1000 μm. Figure 3 As shown. The size of the nanoscale pores on the surface is about 10 to 50 nm. Figure 2 shown.

[0059] The prepared bionic intelligent affinity-repellent freshwater collection fiber is applied to the bionic freshwater collection fiber net with a mesh area of ​​20 cm 2 After the bionic fiber mesh is wetted, water droplets will gather between the knots on the fiber. When the water droplets are large enough, they will fall off automatically after reaching the maximum critical volume under the action of gravity.

[0060] The bionic intelligent affinity-repellent freshwater collection fiber provided by the present invention can be used in the collection of clean water and woven into various fiber nets. The droplets will condense at the bead knots and junctions and finally be transmitted and collected, thus solving the problem of fixed-point collection.

[0061] The bionic intelligent affinity-repellent alternating freshwater collection fiber provided by the present invention can also be used in demisting and collection. In foggy weather around airports, highways, and lighthouses, it can reduce moisture in the air and improve air visibility.

[0062] In step 3 and step 4 of the method for preparing the bionic intelligent hydrophilic freshwater collection fiber provided by the present invention, the height, width and spacing of the bead knots are affected by the polymer concentration and the pulling speed. The greater the polymer solution concentration and the pulling speed, the greater the height and length of the bead knots and the greater the spacing; the smaller the polymer solution concentration and the pulling speed, the smaller the height and length of the bead knots and the smaller the spacing.

[0063] Embodiment 1:

[0064] Step 1: Fiber cleaning:

[0065] The fiber selected is copper fiber with an average diameter of 50 μm. The dust on the fiber surface is first cleaned with detergent, and then the impurities and organic matter on the fiber surface are cleaned with acetone. Then, the acetone residue on the surface is cleaned with ethanol, and finally, the oxide on the fiber surface is cleaned with hydrochloric acid.

[0066] Step 2: Etching of fibers:

[0067] 4 parts by weight of sodium hydroxide are dissolved in 100 parts by weight of water and stirred to dissolve; 1.14 parts by weight of ammonium persulfate are dissolved in 100 parts by weight of water and stirred to dissolve; the two are mixed evenly to obtain a clear and transparent solution, and the copper fiber is placed in the solution and etched for 30 minutes to obtain an etched copper fiber.

[0068] Step 3: Fiber Fixation:

[0069] One end of the etched copper fiber is fixed on the original fiber holder by using colloid, and the other end of the fiber passes through the symmetrical square liquid tank and the movable operating ports on the left and right sides of the dark box UV analyzer in turn, and finally the other end of the etched copper fiber is fixed on the fiber receiver by using colloid.

[0070] Step 4: Prepare a polymer mixed solution with a mass fraction of 8%:

[0071] 7 parts by weight of pretreated polyvinylidene fluoride PVDF and 1 part by weight of isopropyl acrylamide NIPAM were dissolved in 93 parts by weight of N,N-dimethylformamide DMF solvent and 0.3 parts by weight of cross-linking agent N,N-methylenebisacrylamide, and then two drops of photoinitiator 2-hydroxy-2-methylpropiophenone 1173 were added and stirred for 24 hours to turn it into a clear and transparent solution to obtain a polymer solution.

[0072] Step 5: Pull to create a bead knot

[0073] The polymer solution is poured into a square liquid tank with symmetrical channels. The liquid surface is immersed in the fiber, and then it is pulled at a speed of 100mm / min. After the pulling is completed, the surface is first covered with polymer fibers, and then beads are produced.

[0074] Step 6: Fiber curing:

[0075] The fiber covered with the polymer solution on the surface was cured and dried in a dark box UV analyzer at 365 nm to obtain a beaded fiber. The drying conditions were 40% humidity and 23° C., and then dried in a drying oven for 2 minutes.

[0076] Step 7: Freeze drying of beads:

[0077] The prepared beaded fibers were immersed in deionized water for 12 h, removed and frozen with liquid nitrogen, and then freeze-dried with a freeze dryer to obtain bionic freshwater collection fibers with a nanopore structure on the surface.

[0078] Embodiment 2:

[0079] Step 1: Fiber cleaning:

[0080] The original fibers were fixed on the bracket with colloid. The copper fibers with an average diameter of 50 μm were selected. The dust on the fiber surface was first cleaned with detergent, and then the impurities and organic matter on the fiber surface were cleaned with acetone. Then, the acetone residue on the surface was cleaned with ethanol, and finally, the oxide on the fiber surface was cleaned with hydrochloric acid.

[0081] Step 2: Fiber Etching:

[0082] 4 parts by weight of sodium hydroxide are dissolved in 100 parts by weight of water and stirred to dissolve; 1.14 parts by weight of ammonium persulfate are dissolved in 100 parts by weight of water and stirred to dissolve; the two are mixed evenly to obtain a clear and transparent solution, and the copper fiber is placed in the solution and etched for 30 minutes to obtain an etched copper fiber.

[0083] Step 3: Fiber Fixation:

[0084] One end of the etched copper fiber is fixed on the original fiber holder by using colloid, and the other end of the fiber passes through the symmetrical square liquid tank and the movable operating ports on the left and right sides of the dark box UV analyzer in turn, and finally the other end of the etched copper fiber is fixed on the fiber receiver by using colloid.

[0085] Step 4: Prepare a polymer mixed solution with a mass fraction of 10%:

[0086] 7 parts by weight of pretreated polyvinylidene fluoride PVDF and 3 parts by weight of isopropyl acrylamide NIPAM were dissolved in 93 parts by weight of N,N-dimethylformamide DMF solvent and 0.3 parts by weight of cross-linking agent N,N-methylenebisacrylamide, and then two drops of photoinitiator 2-hydroxy-2-methylpropiophenone 1173 were added and stirred for 24 hours to turn it into a clear and transparent solution to obtain a polymer solution.

[0087] Step 5: Pull to create a bead knot

[0088] The polymer solution is poured into a square liquid tank with symmetrical channels. The liquid surface is immersed in the fiber, and then it is pulled at a speed of 100mm / min. After the pulling is completed, the surface is first covered with polymer fibers, and then beads are produced.

[0089] Step 6: Fiber curing:

[0090] The fiber with the polymer solution on the surface was cured and dried in a dark box UV analyzer at 365 nm to obtain a beaded fiber. The drying conditions were 50% humidity and 23° C., and then dried in a drying oven for 1.5 minutes.

[0091] Step 7: Freeze drying of beads:

[0092] The prepared beaded fiber was immersed in deionized water for 18 h, taken out and frozen with liquid nitrogen, and then freeze-dried with a freeze dryer to obtain a bionic freshwater collection fiber with a nanopore structure on the surface.

[0093] The bionic fresh water collection fiber prepared in Example 2 is used to collect water. During the water collection process, the water is transported as follows: Figure 4As shown in the figure, at the beginning, the fiber surface will absorb tiny droplets, and the surface will be completely wetted within about 2 seconds, and a bright water film will form on the surface in about 10 seconds. Under the synergistic force of the surface energy gradient and the Laplace pressure difference, the droplets move from the junction to the spindle knot. After directional movement, as the amount of water collected increases, the water droplets are already below the spindle knot in about 40 seconds, and the small droplets formed continue to converge towards the large droplets, and the large droplets are gradually getting larger. At about 100 seconds, the droplets overcome the critical droplet attachment to the spindle knot and detach from the spindle knot.

[0094] like Figure 5 As shown, the bionic freshwater collection fiber prepared in Example 2 shows that tiny droplets gather and condense on the spindle nodes during the water collection process; when the spindle nodes in a dry state just start to collect fog, tiny droplets condense on the fiber at 2s, and two water droplets are formed on the surfaces of the two spindle nodes at about 20s. The newly emerged small droplets move toward the spindle nodes under the conditions of surface energy gradient and Laplace pressure, covering a single spindle node (50s), and the water droplets slowly grow and merge into a larger water droplet, which is suspended between the two spindle nodes (60s). Finally, the critical volume is reached until the water droplets fall (100s), completing the process of water droplet collection, and the water collection starts the next cycle again, with the maximum volume of suspension being about 5.26μL.

[0095] The bionic freshwater collection fiber prepared in Example 2 was woven into a 5×5 bionic freshwater collection fiber mesh, such as Figure 6 As shown, each fiber is 5 cm long and the area of ​​the small grid is 0.5 cm 2 , the overall fiber web area is 20cm 2 The fiber web was placed at a humidity of 90% to collect water droplets, and the amount of water collected within 60 minutes was 0.1479 g.

[0096] A fiber mesh of the same size was prepared using unetched copper wire fibers for comparison. The fiber mesh was placed at a humidity of 90% to collect water droplets. The amount of water collected within 60 minutes was 0.0099 g, indicating that the fresh water collection fiber mesh prepared in this embodiment has a very high water collection effect.

[0097] Embodiment 3:

[0098] Step 1: Fiber cleaning:

[0099] The original fibers were fixed on the bracket with colloid. The copper fibers with an average diameter of 50 μm were selected. The dust on the fiber surface was first cleaned with detergent, and then the impurities and organic matter on the fiber surface were cleaned with acetone. Then, the acetone residue on the surface was cleaned with ethanol, and finally, the oxide on the fiber surface was cleaned with hydrochloric acid.

[0100] Step 2: Fiber Etching:

[0101] 4 parts by weight of sodium hydroxide are dissolved in 100 parts by weight of water and stirred to dissolve; 1.14 parts by weight of ammonium persulfate are dissolved in 100 parts by weight of water and stirred to dissolve; the two are mixed evenly to obtain a clear and transparent solution, and the copper fiber is placed in the solution and etched for 30 minutes to obtain an etched copper fiber.

[0102] Step 3: Fiber Fixation:

[0103] One end of the etched copper fiber is fixed on the original fiber holder by using colloid, and the other end of the fiber passes through the symmetrical square liquid tank and the movable operating ports on the left and right sides of the dark box UV analyzer in turn, and finally the other end of the etched copper fiber is fixed on the fiber receiver by using colloid.

[0104] Step 4: Prepare a polymer mixed solution with a mass fraction of 12%:

[0105] 7 parts by weight of pretreated polyvinylidene fluoride PVDF and 5 parts by weight of isopropyl acrylamide NIPAM were dissolved in 93 parts by weight of N,N-dimethylformamide DMF solvent and 0.3 parts by weight of cross-linking agent N,N-methylenebisacrylamide, and then two drops of photoinitiator 2-hydroxy-2-methylpropiophenone 1173 were added and stirred for 24 hours to turn it into a clear and transparent solution to obtain a polymer solution.

[0106] Step 5: Pull to create a bead knot

[0107] The polymer solution is poured into a square liquid tank with symmetrical channels. The liquid surface is immersed in the fiber, and then it is pulled at a speed of 150mm / min. After the pulling is completed, the surface is first covered with polymer fibers, and then beads are produced.

[0108] Step 6: Fiber curing:

[0109] The fiber covered with the polymer solution on the surface was cured and dried in a dark box UV analyzer at 365 nm to obtain a beaded fiber. The drying conditions were 60% humidity and 23° C., and then dried in a drying oven for 15 minutes.

[0110] Step 7: Freeze drying of beads:

[0111] The prepared beaded fibers were immersed in deionized water for 24 h, frozen with liquid nitrogen the next day, and then freeze-dried with a freeze dryer to obtain bionic freshwater collection fibers with a nanopore structure on the surface.

[0112] According to the experimental results of the three embodiments, bionic water-collecting fibers were prepared with polymer mass fractions of 8%, 10%, and 12%, respectively. The morphologies were observed and compared after freeze-drying. At a polymer ratio of 10%, the beaded morphology structure on the fiber was relatively better, and the subsequent water collection effect was also relatively better.

Claims

1. A bionic intelligent freshwater collection fiber with alternating affinity and distance, characterized in that: The beads on the fiber are distributed at intervals, each bead is superhydrophobic, and the fiber between the beads is hydrophilic; the height of each bead is 200-300μm, the length is 400-500μm, the surface of the bead has a nanopore structure of 10-50nm, and the distance between two bead is 900-1000μm.

2. The bionic intelligent freshwater collection fiber according to claim 1, characterized in that: A two-dimensional or three-dimensional fiber mesh structure is obtained by weaving.

3. The bionic intelligent freshwater collection fiber according to claim 2, characterized in that: The woven fiber mesh structure is placed in a foggy environment. After the fiber mesh is moistened by the fog, water droplets will condense at the bead knots and the weaving junctions. When the water droplets reach the maximum critical volume, they automatically fall off under the action of gravity, and are transmitted and collected to achieve the purpose of water collection.

4. Application of a bionic intelligent affinity-repellent freshwater collection fiber, characterized in that: Used for demisting and water collection. When used for demisting, when foggy weather occurs around airports, highways and lighthouses, the fiber net woven with fresh water collection fibers can reduce the moisture in the air and improve air visibility; when used for water collection, the fiber net's transmission and collection solves the problem of collecting water at a fixed point and has the effect of purifying water.

5. A method for preparing a bionic intelligent freshwater collection fiber with alternating affinity and repellency, characterized in that: The specific steps are as follows: Step 1, pre-treating the fiber; The fiber is selected from the copper-ammonia fiber among the man-made fibers, and the average diameter of the copper-ammonia fiber is 30-100 μm; Step 2, fixing the pretreated fiber on the experimental device; The experimental device includes a fibril fixing support, a symmetrical channel square liquid tank, a dark box UV analyzer and a fiber receiver; the rotating shaft of the fibril fixing support and the rotating shaft of the fiber receiver have the same diameter and are at the same horizontal position; the symmetrical channel square liquid tank is used to hold the solution, and has a pair of symmetrical small holes with a diameter of 0.5 to 1 mm on the left and right sides, the center of the hole is located on the same straight line, and the fiber passes through the small holes on the left and right sides horizontally; One end of the fiber is wound and fixed on the rotating shaft of the original fiber fixing bracket, and the other end passes through the symmetrical square liquid tank and the dark box UV analyzer in sequence, and finally is wound and fixed on the rotating shaft of the fiber receiver, and the fiber is in a horizontal state as a whole; Step 3, adding polymer a and polymer b to an organic solvent at the same time, adding 0.3 parts by weight of N,N-methylenebisacrylamide and two drops of 2-hydroxy-2-methylpropiophenone 1173 to the organic solvent, stirring for more than 24 hours, and obtaining a polymer solution with a polymer mass fraction of 8 to 12%; The polymer a is any one of polyvinylidene fluoride or polymethyl methacrylate; the polymer b is any one of polyvinylidene alcohol or polyisopropylacrylamide; The ratio of polymer a to polymer b is 7:1-5; The organic solvent is any one of N,N-dimethylformamide or N,N-dimethylacetamide; Step 4: Pour the polymer solution into the symmetrical channel square liquid tank in the experimental device, soak the fiber with the liquid surface, and then pull it at a speed of 100-150 mm / min. After the pulling is completed, the fiber moves out of the symmetrical channel square liquid tank, and the polymer forms beads on the fiber surface. Step 5, the beads on the fiber surface are cured and dried in a dark box UV analyzer to obtain beaded fibers, which are collected on a rotating shaft of a fiber receiver; Step 6, freeze-drying the beaded fiber to obtain a bionic fresh water collection fiber with a nanoporous structure; The prepared beaded fiber was immersed in deionized water for 12 to 24 hours, taken out and frozen with liquid nitrogen, and then freeze-dried with a freeze dryer to obtain a bionic freshwater collection fiber with a nanoporous structure.

6. The method for preparing a bionic intelligent freshwater collection fiber with alternating affinity and repellency according to claim 5, characterized in that: The pretreatment process is specifically as follows: first, the fiber is cleaned with a cleaning agent to remove dust on the surface; then, the fiber is immersed in acetone, ethanol and hydrochloric acid solutions in sequence to remove impurities and oxides on the fiber surface; finally, the fiber is cleaned with water, and after drying, the fiber is etched to increase the roughness of the fiber and enhance its hydrophilicity.

7. The method for preparing a bionic intelligent freshwater collection fiber with affinity and repellency according to claim 6, characterized in that: The etching process is specifically as follows: 4 parts by weight of sodium hydroxide is dissolved in 100 parts by weight of water, and stirred to dissolve; 1.14 parts by weight of ammonium persulfate is dissolved in 100 parts by weight of water, and stirred to dissolve; the two are mixed evenly to obtain a clear and transparent solution, the fiber is placed in the solution, and etched for 30 minutes to obtain an etched fiber.

8. The method for preparing a bionic intelligent freshwater collection fiber with alternating affinity and repellency according to claim 5, characterized in that: The darkbox UV analyzer consists of an observation window, a shooting window, a darkbox, movable operating ports on the left and right sides, and a control panel. The observation window filters out ultraviolet rays for easy observation, and the shooting window is used for camera shooting. The darkbox has a built-in UV lamp, and the angle and performance can be adjusted at will to allow the light source to illuminate any position in the darkbox. The movable operating ports on the left and right sides are symmetrical opening and closing doors to ensure that the fiber is placed horizontally in the darkbox. There are three controllable wavelength switches on the surface of the control panel.

9. The method for preparing a bionic intelligent freshwater collection fiber with alternating affinity and repellency according to claim 5 or 8, characterized in that: Drying conditions in the dark box UV analyzer: UV wavelength 365nm, humidity 40% to 60%, temperature 23°C, drying time 1.5 to 15min.

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