CN111411353A

CN111411353A - Method for collecting water mist by using silica gel block material with hydrophilic and sliding surface and tapered copper needle with super-hydrophobic-hydrophilic surface

Info

Publication number: CN111411353A
Application number: CN202010066921.3A
Authority: CN
Inventors: 郭志光; 周慧
Original assignee: Hubei University
Current assignee: Hubei University
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2020-07-14
Anticipated expiration: 2040-01-20
Also published as: CN111411353B

Abstract

The invention provides a method for collecting water mist by using a silica gel block material with a hydrophilic sliding surface and a conical copper needle with a super-hydrophobic-hydrophilic surface. The method comprises the steps of preparing a copper surface with a nano bulk structure by an electrodeposition method, preparing copper hydroxide nanowires at the tip of a copper needle after electrodeposition, preparing a conical copper needle with a super-hydrophobic-hydrophilic integrated surface, preparing a silica gel bulk material with a hydrophilic and sliding surface, and collecting and combining water mist by taking the silica gel bulk material with the hydrophilic and sliding surface as a substrate and assembling the silica gel bulk material with the conical copper needle with the super-hydrophobic-super-hydrophilic integrated surface together. The collection rate of each substrate assembled with one copper needle is about 9.05g/h, and the collection rate of each substrate assembled with six copper needles is about 14.19 g/h. Therefore, the water mist collection combination which takes the hydrophilic and sliding block material as the substrate and is assembled with the conical copper needle on the super-hydrophobic-super-hydrophilic integrated surface can be popularized in a large scale based on stable and efficient water mist collection capacity and long-term stable wettability of the surface of the material.

Description

Method for collecting water mist by using silica gel block material with hydrophilic and sliding surface and tapered copper needle with super-hydrophobic-hydrophilic surface

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a method for collecting water mist by preparing a silica gel block material with a hydrophilic sliding surface and a conical copper needle with a super-hydrophobic-hydrophilic integrated surface.

Background

Materials with water-collecting properties have received increasing attention in recent years. Water shortage is reported to be one of the pressing issues facing the future for human beings. How to quickly and efficiently collect moisture from humid air becomes a challenge. It is well known that in deserts or coastal countries, fog is generally present in humid atmospheres. The organisms in the nature have evolved surface microstructures that are conducive to water collection, which gives scientists the inspiration of biomimetic research. Cactus discloses a unique integrated water collection system that incorporates a spike to accelerate the transport of micro-droplets. In addition, the uneven back of the nano-budworm, which is composed of a hydrophobic waxy region and a hydrophilic non-waxy region, provides convenience for collecting drinking water from the air. Researches show that the water collection capacity of the surface of the material is controlled on the structural characteristics by utilizing the bionics technology, and the method is a feasible method by combining physical and chemical properties. Especially, the combination between multiple gradients in physics and chemistry (e.g., laplace pressure difference generated by geometry, wetting gradient, etc.) plays an important role in facilitating droplet transport. In recent years, the problem of efficient water mist collection is solved and unidirectional transport of liquid droplets is realized by utilizing a method of combining surface shape gradient, magnetic excitation response, asymmetric wettability and an anisotropic porous structure with a temperature response lubricating fluid. In fact, the rapid movement of the drop is always difficult to achieve under the action of a single gradient force, the transport of the drop being limited by a certain length. Therefore, how to design an excellent device to improve the efficiency of water mist collection is still a great challenge.

Depositing a copper surface with a micro-nano block structure on the surface of an original copper needle with a smooth surface by an electrodeposition method, and polishing the surface of the electrodeposition needle with the length of 1cm at the tip by using sand paper until the deposited copper disappears. And then, etching the treated copper needle tip on the surface by using alkaline ammonia to prepare a copper hydroxide nanowire, and modifying by using a 1-octadecyl mercaptan/ethanol solution to successfully prepare the tapered copper needle surface with the super-hydrophobic-hydrophilic integrated surface. In addition, by mixing the dispersed water and TiO₂The nanoparticle solution was added dropwise to uncured PDMS to prepare a silica gel bulk material having a porous structure, and the surface of the sample was polished with sandpaper (400 mesh), thereby successfully preparing a superhydrophobic silica gel bulk material. And spin-coating the ionic liquid BMIMPF6 on a super-hydrophobic surface to obtain a silica gel bulk material with a hydrophilic and sliding surface. The tapered copper needle with the super-hydrophobic-hydrophilic integrated surface has the directional transportation behavior of liquid (from the tip to the super-tail) at room temperature, has good water mist collection capacity, performs water mist collection at different angles (0 degrees, 10 degrees, 20 degrees, -10 degrees, -20 degrees), has the best efficiency when placed horizontally, and improves the water mist collection quality by about 141 percent compared with the original copper needle. Compared with the prepared single cone-shaped copper needle with the super-hydrophobic-hydrophilic integrated surface and the prepared silica gel block material with the hydrophilic and sliding surface, the combination of the silica gel block material with the hydrophilic and sliding surface and the cone-shaped copper needle with the super-hydrophobic-hydrophilic integrated surface is used for water mist collection, so that the water mist collection rate is greatly improved. In addition, the surface wettability of the prepared sample did not change significantly after standing at room temperature for a long time. Therefore, the water mist collection combination which takes the hydrophilic and sliding block material as the substrate and assembles the tapered copper needle of the super-hydrophobic-super-hydrophilic integrated surface together (the tapered copper needle is arranged perpendicular to the surface of the substrate) can be popularized in a large scale based on stable and efficient water mist collection capability and long-term stable wettability of the surface of the material.

Disclosure of Invention

The invention aims to provide a simple, convenient and industrially producible water collection combination of a silica gel block material with a hydrophilic and sliding surface and a conical copper needle with a super-hydrophobic-hydrophilic integrated surface, which not only utilizes the conical shape of the material to promote the movement of liquid drops, but also combines surface chemistry to further improve the capturing and transporting process in the water collection process. Solves the problems of complex preparation steps of the water collecting material, fluorine-containing toxic substances and the like in the preparation material and low practicability. The water mist collecting capacity of the single super-hydrophobic silica gel block material or the cone-shaped copper needle on the super-hydrophobic-hydrophilic integrated surface is poor, the combination of the super-hydrophobic silica gel block material and the cone-shaped copper needle on the super-hydrophobic-hydrophilic integrated surface can be used for quickly collecting water, the absorption and removal of liquid drops are accelerated by further combining the hydrophilic silica gel block material on the sliding surface, and the energy consumption is greatly reduced. The invention prepares and designs a combination by a simple method: the combination further improves the water collection efficiency, has stable wetting performance, high-efficiency and durable water mist collection capacity and reusability, and is beneficial to large-scale popularization and preparation.

The technical scheme for realizing the purpose of the invention is as follows: the method for collecting the water mist by using the silica gel block material with the hydrophilic and sliding surface and the conical copper needle with the super-hydrophobic and hydrophilic surface is characterized by comprising the following steps of:

A. the electrodeposition method is used for preparing the copper surface with the nano bulk structure: firstly, selecting a copper needle with the length of 3cm, respectively ultrasonically cleaning the copper needle with ethanol and deionized water for 5-10min in order to remove pollutants on the surface of the copper needle, then removing an oxide layer with 0.1M hydrochloric acid solution, and carrying out electrodeposition on the treated copper needle by using an electrochemical workstation, wherein the copper needle is used as a cathode, a platinum electrode is used as an anode, a saturated calomel electrode is used as an auxiliary electrode, the selected electrolyte is 0.5-0.7M copper sulfate solution, depositing 400-fold ion 600s in a time-current window, taking out the copper needle, cleaning with ethanol, and drying under nitrogen flow for 1-3 min;

B. preparing copper hydroxide nanowires at the tip of the copper needle after electrodeposition: firstly, polishing the surface of the electro-deposition copper needle with the length of 1cm at the tip end by using sand paper until the deposited copper disappears, then, putting the treated copper needle into a mixed aqueous solution of 0.5-1M sodium hydroxide and 0.03-0.05M ammonium persulfate for etching for 40-60min, washing by using deionized water, and then, putting the washed copper needle into a vacuum drying oven for drying for 5-10 min;

C. preparing a conical copper needle with a super-hydrophobic-hydrophilic integrated surface: modifying the part with the copper hydroxide nanowires in the step B by using a 2-3m M1-octadecyl mercaptan/ethanol solution for 30-50s to form a tapered copper needle surface with a super-hydrophobic-hydrophilic integrated surface;

D. preparation of silica gel block material with hydrophilic, gliding surface: sylgard 184 was first mixed with the curing agent in a 10:1 mass ratio in a 50ml beaker, then dispersing TiO2 nano particles with the diameter of 25nm and water according to the mass ratio of 1:10, dropwise adding the dispersed water and TiO2 nano particle solution into uncured PDMS at the speed of 50-60ml/h, stirring for 2-3h in a magnetic stirring device with the rotating speed of 3000 plus 4000rpm, pouring the emulsion into a polytetrafluoroethylene bottle as a mold, degassing in a vacuum drying oven for 4-5 hr, sealing the polytetrafluoroethylene bottle, standing at 65-70 deg.C for 4-5 hr, then taking the cured PDMS out of the polytetrafluoroethylene bottle, placing the PDMS at 190 ℃ for 2-3h under 180 DEG, and finally, sanding the surface of the sample by using sand paper until the surface of the sample presents super-hydrophobicity, and spin-coating the ionic liquid BMIMPF6 on the super-hydrophobic surface at the rotating speed of 3000-4000 rpm;

E. the water mist collection combination is characterized in that a silica gel block material with a hydrophilic sliding surface is used as a substrate and is assembled with a conical copper needle with a super-hydrophobic-super-hydrophilic integrated surface: a silica gel block material with a radius of 1.5cm and a hydrophilic sliding surface is taken as a substrate, a conical copper needle with a length of 3cm and a super-hydrophobic-hydrophilic integrated surface is vertically inserted into the block material, the conical copper needle is kept horizontal to the ground, the distance between the combination and a mist outlet is kept between 4 and 6cm, the duration time of one-time periodic measurement of a water mist collection experiment is 1 hour, the flow rate and the speed of a humidifier used for the water collection experiment are respectively 0.0556g s-1 and 25cm s-1, and in the experiment, the temperature and the relative humidity around a sample are respectively 15 ℃ and 70%.

Furthermore, in the step A, the copper needle is deposited in 0.5-0.7M copper sulfate solution, the electrolyte solution must be uniformly mixed, and the electrode device must be cleaned.

Further, in the step B, the copper needle is etched in 0.5-1M sodium hydroxide and 0.03-0.05M ammonium persulfate alkali solution, and the solutions must be uniformly mixed.

Furthermore, when 2-3mM 1-octadecyl mercaptan/ethanol solution is used for wettability modification, the modification time needs to be strictly controlled within 30-50s, and the nano rod-shaped structure is ensured and the super-hydrophobic performance is expressed.

Furthermore, the silica gel block material needs to be fully degassed, and the moisture is fully evaporated at the high temperature of 190 ℃ in 180-fold mode, so that a porous structure appears, and the lower surface of the silica gel block material polished by abrasive paper is super-hydrophobic.

Furthermore, the surface of the copper needle has a hydrophilic-super-hydrophobic wetting gradient, the tip is super-hydrophobic, the two thirds of the length of the tail is hydrophilic, and the copper needle is combined with a silica gel block material with hydrophilic sliding property on the surface for collecting water mist.

The invention has the beneficial effects that: compared with the prior art, the invention has the advantages that:

1. the tapered copper needle on the super-hydrophobic-hydrophilic integrated surface has good water collection capacity, the water collection amount per hour is about 2.69g, the efficient water mist collection rate is achieved under different inclination angles, and compared with an original copper needle, the water mist collection rate of the tapered copper needle on the super-hydrophobic-hydrophilic integrated surface is improved by about 141%;

2. the collection rate of the single hydrophilic and gliding silica gel block material as a substrate water is 5.858g/h, and the single hydrophilic and gliding silica gel block material has higher water collection efficiency than a super-hydrophobic and hydrophobic gliding block material;

3. combining a hydrophilic and sliding silica gel block material as a substrate with a tapered copper needle on a super-hydrophobic-super-hydrophilic integrated surface for water mist collection, wherein the collection rate is about 9.05g/h when one copper needle is assembled on each substrate, and the collection rate is about 14.19g/h when the number of the assembled copper needles is increased to six;

4. the prepared conical copper needle with the super-hydrophobic-hydrophilic integrated surface has good liquid transportation performance, and the L aplace pressure difference and the wetting gradient on the surface promote the directional transportation behavior of liquid, so that the energy consumption is reduced;

5. the designed water mist collecting material and the combination of the water mist collecting material and the water mist collecting material combine two aspects of surface appearance and chemistry at the same time, and have high and durable collecting efficiency and can be repeatedly utilized.

Drawings

FIG. 1: example 1 results are a preparation process diagram for copper needles with an integrated superhydrophobic-hydrophilic surface and electron microscopy images of original copper needles, electrochemically deposited copper needles, alkali ammonia etched copper needles, post-etched thiol modified copper needles and a static water contact angle diagram on the corresponding sample surface. Wherein, the figure a is a diagram of a water mist collecting device, and the figures b-e are respectively a diagram of a preparation process of copper needles with different wettability; and f-o are respectively electron microscope images of the surface of the silica gel block material, the original copper needle, the electrochemical deposition copper needle, the alkali ammonia etched copper needle and the surface of the copper needle modified by mercaptan after etching, and the image at the upper right corner of the electron microscope image is a static water contact angle image on the surface of the corresponding sample.

FIG. 2: example 2, the three-dimensional surface contour maps of the samples are obtained, wherein the maps a-d are the three-dimensional surface contour maps of original copper needles, alkaline ammonia etched copper needles, thiol modified copper needles after etching and electrochemical deposition copper needles, and the roughness of the material surface is 267nm, 629nm, 281nm and 473nm respectively.

FIG. 3: the result of example 3 is a water collection quality graph of copper needles with different wettabilities, wherein a is a water collection quality graph of copper needles with different wettabilities in one hour, b is a water collection quality graph of conical copper needles with a superhydrophobic-hydrophilic integrated surface under different inclination angles, and c is a schematic diagram of directional transport of liquid droplets on the conical copper needles with the superhydrophobic-hydrophilic integrated surface.

FIG. 4: example 4 resulted in water collection plots for copper needles with different wettabilities, where plot a is an optical photograph of nucleation, coalescence, and transport of water droplets on the inner surface of the original copper needle in 0-70s, plots b and c are optical photographs of surface-forming water droplets gradually changing over 0-45s for the superhydrophilic, superhydrophobic copper needle surface with uniform wettability, and plot d is an optical photograph of surface-forming water droplets gradually changing over 0-40s for the tapered copper needle surface with superhydrophobic-hydrophilic integration surface.

FIG. 5 is a schematic diagram of water collection in example 5, wherein a and b are schematic diagrams of water mist collection in combination of a silica gel block material with a hydrophilic and gliding surface and a tapered copper needle with a superhydrophobic-hydrophilic integrated surface, and the process comprises the capture, transportation and collection of mist droplets, and a schematic diagram of water collection quality in different combinations, wherein c is a schematic diagram of water collection quality in one hour for a silica gel block material with a superhydrophobic surface, a silica gel block material with a hydrophobic and gliding surface, and a silica gel block material with a hydrophilic and gliding surface (3cm × 3cm), and d is a schematic diagram of water collection quality in six consecutive hours for a silica gel block material with a hydrophilic and gliding surface, a tapered copper needle with a superhydrophobic-hydrophilic integrated surface, and a device with one or six wettability-gradient copper needles, each combined, and weighed once per hour.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples. Various changes or modifications may be effected therein by one skilled in the art and such equivalents are intended to be within the scope of the invention as defined by the claims appended hereto.

Example 1

1. The electrodeposition method is used for preparing the copper surface with the nano bulk structure: firstly, selecting a copper needle with the length of 3cm, respectively carrying out ultrasonic cleaning for 5min by using ethanol and deionized water in order to remove pollutants on the surface of the copper needle, and then removing an oxidation layer by using a 0.1M hydrochloric acid solution. And performing electrodeposition on the treated copper needle by using an electrochemical workstation, wherein the copper needle is used as a cathode, a platinum electrode is used as an anode, a saturated calomel electrode is used as an auxiliary electrode, and the selected electrolyte is 0.5M copper sulfate solution. 600s were deposited under the time-current window. The copper needle was removed, rinsed with ethanol and dried under nitrogen flow for 3 min.

2. Preparing copper hydroxide nanowires at the tip of the copper needle after electrodeposition: first, the surface of the electrodeposited copper pin with a tip of 1cm length was polished with sandpaper until the deposited copper disappeared. Then, the treated copper needle is put into a mixed aqueous solution of 1M sodium hydroxide and 0.05M ammonium persulfate for etching for 60min, and the copper needle is cleaned by deionized water and then is dried in a vacuum drying oven for 5 min.

3. Preparing a conical copper needle with a super-hydrophobic-hydrophilic integrated surface: and (3) modifying the part with the copper hydroxide nanowires in the step B by using a 2mM 1-octadecyl mercaptan/ethanol solution for 30s to form a conical copper needle surface with a super-hydrophobic-hydrophilic integrated surface.

4. Preparation of silica gel block material with hydrophilic, gliding surface: sylgard 184 and the curing agent were first mixed in a 10:1 mass ratio in a 50ml beaker, followed by the addition of TiO 25nm in diameter₂The nanoparticles were dispersed with water in a mass ratio of 1: 10. Mixing the dispersed water with TiO₂The nanoparticle solution was added dropwise to the uncured PDMS at a rate of 60ml/h and stirred in a magnetic stirring apparatus at 4000rpm for 2 h. The emulsion was then poured into a teflon bottle as a mold and degassed in a vacuum oven for 4 h. After degassing, the teflon bottle was sealed and placed at 65 ℃ for 4 h. The cured PDMS was then removed from the Teflon bottle and placed at 180 ℃ for 2 h. Finally, the sample surface was sanded with sandpaper (400 mesh) until the sample surface appeared superhydrophobic. The ionic liquid BMIMPF6 was spin coated on a superhydrophobic surface at 4000 rpm.

5. And (3) characterizing the surface microstructures of the silica gel block material and the copper needles with different wetabilities: wherein, the surface of the silica gel block material has a porous micro-nano structure, TiO₂The nano particles are uniformly distributed; the original copper needle surface was smooth with a static contact angle of about 92.49 ° on the surface; the surface of the electrochemical deposition copper needle is provided with a blocky micro-nano structure, and the static contact angle on the surface is about 49 degrees; performing alkali ammonia etching on the tip part of the electrochemical deposition needle, uniformly distributing copper hydroxide nano needles on the surface, and ensuring that the static contact angle is about 10 degrees; the surface of the alkali ammonia etching part after thiol modification has a nanorod structure, and the static contact angle is about 154.99 degrees.

Example 2

4. Preparation of silica gel block material with hydrophilic, gliding surface: sylgard 184 was first mixed with the curing agent in a 10:1 mass ratio in a 50ml beaker, and then TiO2 nanoparticles 25nm in diameter were dispersed with water in a 1:10 mass ratio. The dispersed water and TiO2 nanoparticle solution were added dropwise to uncured PDMS at a rate of 60ml/h, and stirred in a magnetic stirring apparatus at a rotation speed of 4000rpm for 2 h. The emulsion was then poured into a teflon bottle as a mold and degassed in a vacuum oven for 4 h. After degassing, the teflon bottle was sealed and placed at 65 ℃ for 4 h. The cured PDMS was then removed from the Teflon bottle and placed at 180 ℃ for 2 h. Finally, the sample surface was sanded with sandpaper (400 mesh) until the sample surface appeared superhydrophobic. The ionic liquid BMIMPF6 was spin coated on a superhydrophobic surface at 4000 rpm.

5. Carrying out three-dimensional profile test on copper needles with different wettabilities: the roughness of the original copper needle surface is 267nm, the roughness of the alkaline ammonia etching copper needle surface is 629nm, the roughness of the mercaptan modified copper needle surface is 281nm, and the roughness of the electrodeposited copper needle surface is 473 nm.

Example 3

5. Carrying out water mist collection experiments on copper needles with different wettabilities: performing water collection experiments on an original copper needle, a super-hydrophilic copper needle after alkaline ammonia etching, a thiol-modified super-hydrophobic copper needle and a tapered copper needle with a super-hydrophobic-hydrophilic integrated surface, and measuring the quality of water collected per hour, wherein the copper needle with the wettability gradient has the best water collection efficiency. The inclination angle of the conical copper needle with the super-hydrophobic-hydrophilic integrated surface is changed to carry out a water collection experiment, and when the conical copper needle is horizontally placed, the water collection efficiency is highest.

Example 4

5. Nucleation, accumulation and directional transportation of liquid drops on the surfaces of copper needles with different wettabilities: (1) for the original copper needle: the small fog drops are continuously captured and gradually accumulated to be larger for about 5s, directional transportation of the liquid drops begins to occur, the liquid drops are transported from the tip end to the tail end of the needle, the liquid drops are continuously larger at the tail end, and the liquid drops fall and are collected under the action of gravity; (2) for super-hydrophilic copper needles: the small fog drops are continuously captured, a layer of water film is gradually formed on the surface of the copper needle, the copper needle starts to move from the tip to the tail in about 10s, and the liquid drops are accumulated and dropped along with the increase of time; (3) for superhydrophobic copper needles: the small fog drops are quickly captured and gradually enlarged, and the adjacent liquid drops are combined together and then drop after being gradually enlarged; (4) for a conical copper needle with a super-hydrophobic-hydrophilic integrated surface, liquid drops are continuously captured and enlarged at a tip part, move in an accelerated manner after directionally moving to a part with a wettability gradient, continuously accumulate and enlarge at a hydrophilic surface, and drop and collect under the action of gravity.

Example 5

5. The water mist collection combination is characterized in that a silica gel block material with a hydrophilic sliding surface is used as a substrate and is assembled with a conical copper needle with a super-hydrophobic-super-hydrophilic integrated surface: a silica gel block material with a radius of 1.5cm and a hydrophilic sliding surface is taken as a substrate, a conical copper needle with a length of 3cm and a super-hydrophobic-hydrophilic integrated surface is vertically inserted into the block material, the conical copper needle is kept horizontal to the ground, the distance between the combination and a mist outlet is kept at 6cm, the one-time periodic measurement duration of a water mist collection experiment is 1 hour, and the flow rate and the speed of a humidifier used for the water collection experiment are respectively 0.0556g s-1 and 25cm s-1. In the experiment, the temperature and relative humidity around the sample were 15 ℃ and 70%, respectively.

6. And (3) water mist collection test, namely performing a water mist collection experiment on the copper needles with different wettabilities, the silica gel block materials and the newly designed water collection combination, and measuring the water collection quality of the block materials with different wettabilities per hour. Comparing the water collection quality of block materials with different wettability, the silica gel block material with hydrophilic and sliding surfaces has the maximum water collection quality per hour; and further combining a block material with a hydrophilic and sliding surface with a tapered copper needle with a super-hydrophobic-hydrophilic integrated surface for a water mist collection experiment, measuring the mass of the collected water once per hour, and obviously improving the water collection quality of the combined device from one hour to six hours.

7. The principle analysis of water mist collection includes that mist drops are captured on the surface of a conical copper needle with a super-hydrophobic-hydrophilic integrated surface, the capture speed of a super-hydrophobic part is high, L aplace forces are different in front and at the back of the mist drops under the conical shape, the liquid drops are promoted to move backwards, the liquid drops captured on the hydrophilic surface gradually grow to form a water film, the liquid drops on the super-hydrophobic side move to a wettability gradient and quickly move to be combined with the liquid drops on the hydrophilic surface and then continuously move backwards, when the liquid drops contact the surface of a hydrophilic and sliding silica gel block material, a stable water bridge is formed to accelerate the movement of the liquid drops, and finally the liquid drops are quickly removed on the sliding surface after being accumulated on the surface of the block material.

The method comprises the steps of etching the copper hydroxide nanowires by alkali ammonia, electrodepositing the copper surface of a nano bulk structure, preparing the silica gel bulk material containing nano titanium dioxide nanoparticles and the like. The silica gel block material mixed with the nano titanium dioxide particles has excellent weather resistance, the surface of the material is polished by sand paper, the material shows unique super-hydrophobicity at room temperature, and the silica gel block material has better oil locking capability after being coated with hydrophilic oil and still has stable sliding capability after being placed for a long time. For the conical copper needle with the super-hydrophobic-hydrophilic integrated surface, the tip part is distributed with copper hydroxide nano needles, and after the copper hydroxide nano needles are modified into super-hydrophobic property by mercaptan, the capture process in the mist collection process is facilitated; the hydrophilic section of the latter half and the copper surface of the tiled nano-bulk structure further promote the movement of liquid droplets, improving the overall process of mist collection as a whole. The cone-shaped copper needle with the independent super-hydrophobic-hydrophilic integrated surface has good water collecting capacity and high-efficiency water mist collecting rate under different inclination angles. The water mist collection rate is improved by about 141 percent compared with the original copper needle water mist collection rate. In addition, the water mist collection combination which takes the bulk material as the substrate and is assembled with the tapered copper needle of the super-hydrophobic-super-hydrophilic integrated surface (the tapered copper needle is arranged perpendicular to the surface of the substrate) has more efficient water collection capability. Once the liquid drops move to the surface of the block material through the tapered copper needle on the super-hydrophobic-hydrophilic integrated surface, the liquid drops form a water bridge due to the hydrophilicity of the surface of the material, and the sliding surface accelerates the rapid removal of the liquid drops, so that the water collection effect is achieved. The collection rate when one copper needle was assembled per substrate was about 9.05g/h, and the collection rate when the number of assembled copper needles was increased to six was about 14.19 g/h. Therefore, the water mist collection combination which takes the hydrophilic and sliding block material as the substrate and assembles the tapered copper needle of the super-hydrophobic-super-hydrophilic integrated surface together (the tapered copper needle is arranged perpendicular to the surface of the substrate) can be popularized in a large scale based on stable and efficient water mist collection capability and long-term stable wettability of the surface of the material.

Finally, it should be noted that the above-mentioned contents are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, and that the simple modifications or equivalent substitutions of the technical solutions of the present invention by those of ordinary skill in the art can be made without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. The method for collecting the water mist by using the silica gel block material with the hydrophilic and sliding surface and the conical copper needle with the super-hydrophobic and hydrophilic surface is characterized by comprising the following steps of:

2. The method of claim 1, wherein the method comprises the following steps: in the step A, the copper needle is deposited in 0.5-0.7M copper sulfate solution, the electrolyte solution must be uniformly mixed, and the electrode device must be cleaned.

3. The method of claim 1, wherein the method comprises the following steps: in step B, the copper needle is etched in 0.5-1M sodium hydroxide and 0.03-0.05M ammonium persulfate alkali solution, and the solutions must be uniformly mixed.

4. The method of claim 1, wherein the method comprises the following steps: when 2-3mM 1-octadecyl mercaptan/ethanol solution is used for wettability modification, the modification time needs to be strictly controlled within 30-50s, and the nano-rod-shaped structure is ensured and the super-hydrophobic performance is expressed.

5. The method of claim 1, wherein the method comprises the following steps: the silica gel block material needs to be fully degassed, and the moisture is fully evaporated at the high temperature of 180-190 ℃, so that a porous structure appears, and the lower surface polished by the abrasive paper shows super-hydrophobicity.

6. The method of claim 1, wherein the method comprises the following steps: the surface of the copper needle has a hydrophilic-super-hydrophobic wetting gradient, the tip is super-hydrophobic, the two thirds of the length of the tail is hydrophilic, and the copper needle is combined with a silica gel block material with hydrophilic slippage on the surface for water mist collection.