A high-efficiency mist collector unaffected by mist flow direction and its preparation method

Abstract

This invention relates to a high-efficiency fog collector unaffected by fog flow direction and its manufacturing method. First, a superhydrophobic coating is formed on the surface of a copper sheet. Then, patterns are drawn on the copper sheet using a laser as punctuation marks. After electroplating, multiple superhydrophilic protrusions are formed. Finally, a uniquely shaped umbrella-like structure is formed through plastic stamping. The fog collector provided by this invention not only has high fog collection efficiency and adapts to any fog flow direction, but also uses abundant and readily available raw materials. Furthermore, the manufacturing process is simple, time-saving, and highly efficient, providing new ideas for the design of future high-efficiency fog collectors.

Description

Technical Field

[0001] This invention relates to the field of wettable surface technology, specifically to a high-efficiency mist collector and its preparation method that are not affected by the direction of mist flow. Background Technology

[0002] Currently, mature methods for obtaining freshwater resources are divided into seawater desalination and mist collection. While seawater desalination can effectively collect freshwater, it suffers from significant regional limitations, high costs, and high energy consumption, making it unsuitable for all locations. Conversely, biomimetic mist collection, inspired by plants and animals, can largely overcome these drawbacks. Mist collectors inspired by cacti, beetles, and spider silk have been extensively constructed, all exhibiting high mist collection efficiency. However, because these mist collectors are based on the micro- and nano-structures of plants and animals, their surfaces are easily damaged, making it difficult for them to operate continuously in harsh environments.

[0003] Furthermore, with ongoing human production activities, atmospheric warming is becoming increasingly severe each year, leading to a decrease in the duration and frequency of fog formations. Additionally, the direction of fog flow may change unpredictably, in which case traditional unidirectional fog collectors will become ineffective. Summary of the Invention

[0004] This invention provides a high-efficiency mist collector unaffected by the direction of mist flow and its preparation method. The mist collector has a superhydrophobic coating on its surface and hydrophilic protrusions are prepared by electrodeposition, which facilitates the condensation of droplets and ensures their smooth flow. After being molded, the mist collector forms multiple circumferential slopes, which increases the collision of mist flow within the collector, improves the mist capture capability, and is independent of the direction of the mist flow.

[0005] The solution of the present invention to solve the above technical problems is as follows: a high-efficiency fog collector that is not affected by the direction of fog flow, wherein the fog collector uses a copper sheet as the base material, the surface of the copper sheet is provided with a superhydrophobic coating, and the superhydrophobic coating is provided with a plurality of superhydrophilic protrusions.

[0006] The copper sheet is formed into an irregular umbrella-shaped structure by axial bending. The vertex of the irregular umbrella-shaped structure is the center of the copper sheet. The irregular umbrella-shaped structure includes several first ridges evenly spaced around the vertex. The first ridges all extend from the center of the copper sheet to the same side of the copper sheet and have the same angle with the original copper sheet plane. A second ridge is provided between each two adjacent first ridges. The second ridges all extend from the center of the original copper sheet to the same side of the original copper sheet and have the same angle with the original copper sheet plane. The adjacent first ridges and second ridges are connected by a plane to finally form the irregular umbrella-shaped structure. The first ridges and second ridges are all located on the same side of the original copper sheet plane, and the angles between the first ridges and second ridges and the original copper sheet plane are different.

[0007] Preferably, the shape of the superhydrophilic protrusion includes a circle, a triangle, a square, a pentagon, or a hexagon. More preferably, the shape of the superhydrophilic protrusion is pentagonal.

[0008] Preferably, the average diameter of the superhydrophilic protrusions is 1-3 mm, and the density is 4-10 protrusions / cm². 2 .

[0009] The method for preparing a high-efficiency fog collector, as described above, which is unaffected by the direction of fog flow, includes the following steps:

[0010] 1) Polydimethylsiloxane (PDMS) and superhydrophobic nano silica (model: Aerosil R202) were added to n-hexane and mixed evenly. Then, a curing agent was added to obtain a superhydrophobic spraying liquid. Copper sheets were ultrasonically treated in 0.1M hydrochloric acid solution, anhydrous ethanol and deionized water for five minutes in sequence to remove the oxide layer on the surface of the copper sheets. The superhydrophobic spraying liquid was then sprayed onto the surface of the copper sheets and cured under constant temperature conditions to obtain SHB.

[0011] 2) Multiple punctuation marks are formed by drawing patterns on the surface of SHB using a laser, resulting in SSHP;

[0012] 3) Electroplating is performed by placing SSHP in CuSO4 solution as the cathode and using metallic copper of the same size as SSHP as the anode. The side of SSHP with patterned markings faces the anode and is kept 5cm away, resulting in SSHB with multiple superhydrophilic protrusions.

[0013] 4) Place the SSHB into a mold and shape it to obtain the fog collector SUSHB.

[0014] Preferably, in step 1), the mass ratio of PDMS to superhydrophobic nano-silica is 5-8:3-6; and the mass ratio of PDMS to curing agent is 7-10:1. More preferably, in step 1), the mass ratio of PDMS to superhydrophobic nano-silica is 5:3; and the mass ratio of PDMS to curing agent is 10:1.

[0015] Preferably, in step 1), the spraying pressure is set to 0.2-0.5 MPa and the spraying distance is 20 cm.

[0016] Preferably, in step 1), the curing temperature is 80°C and the curing time is 2 hours.

[0017] Preferably, in step 3), the electroplating is set to a constant current mode of 0.2A and the electroplating time is 90 minutes.

[0018] Preferably, in step 3), the CuSO4 solution concentration is 0.5M.

[0019] The beneficial effects of this invention are:

[0020] 1. The influence of the fog flow direction can be ignored during the fog collection process.

[0021] 2. It has excellent weather resistance and can collect fog in harsh environments.

[0022] 3. High collection efficiency, simple preparation process, and low raw material price.

[0023] 4. The superhydrophobic protrusions have a polygonal shape, providing more nucleation sites and resulting in faster droplet polymerization.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0026] Figure 1 Here is a structural diagram of the fog collector SUSHB in Example 1; a is a front view of the fog collector SUSHB; b is an enlarged view of the bottom details of the fog collector SUSHB.

[0027] Figure 2 This is a flowchart illustrating the preparation process of the SUSHB mist collector from Example 1.

[0028] Figure 3 The images show the morphology and contact angle test results of the intermediate products from each step in Example 1.

[0029] (a) Optical photographs of the original copper sheet, SHB, SSHP, SSHB, and SUSHB, respectively; (b) Optical photograph of the 3D model; (c) SEM image of the original copper sheet; (df) SEM image of SHB; (gj) SEM image of SSHP; (kn) SEM image of SSHB; (o) Contact angle of the original copper sheet; (p) Contact angle of SHB; (q) Contact angle of the laser-marked pattern of SSHP; (r) Contact angle of the raised area after electrodeposition of SSHB; (st) EDS image of the laser-marked area (Pattern); (uv) EDS image of the raised area (Bump) after electrodeposition.

[0030] Figure 4 XPS spectra of the intermediate products from each step in Example 1;

[0031] (a) XPS full spectrum of the laser-marked area; (b) Fine spectrum of Cu at the laser-marked area; (c) XPS full spectrum of the electrodeposition area; (d) Fine spectrum of Cu at the electrodeposition area;

[0032] Figure 5 This is a droplet polymerization diagram of the original copper sheet, SHB, SSHP, and SSHB in Example 1;

[0033] Figure 6 This is a diagram of droplet aggregation on a single pentagonal protrusion on an SSHB in Example 1;

[0034] Figure 7 This is a graph showing the contact angle variation during electrodeposition testing in Example 1.

[0035] Figure 8 This is a graph showing the change in contact angle during UV testing in Example 1;

[0036] Figure 9 This is a graph showing the change in contact angle during the wear resistance test in Example 1;

[0037] Figure 10 This is a graph showing the change in contact angle during the sand impact test in Example 1.

[0038] Figure 11 This is a graph showing the change in contact angle during the acid and alkali resistance test in Example 1.

[0039] Figure 12 This is a comparison chart of the fog collection efficiency of each sample in the fog collection test experiment of Example 1;

[0040] Figure 13 These are schematic diagrams showing the water collection weight of SSHB with different morphological hydrophilic protrusions in Examples 2-6;

[0041] Figure 14 This is a schematic diagram showing the weight of water collected from intermediate products with different numbers of hydrophilic protrusions in each step of Examples 1, 2, 7-9.

[0042] Figure 15 This is a schematic diagram showing the weight of water collected from intermediate products with different tilt angles in each step of Examples 1, 10-12.

[0043] The attached diagram lists the components represented by each number as follows:

[0044] 1. Copper sheet; 2. Superhydrophobic coating; 3. Superhydrophilic protrusions; 4. First ridge line; 5. Second ridge line. Detailed Implementation

[0045] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0046] Example 1

[0047] like Figures 1-2 As shown, this embodiment provides a fog collector SSHB and its preparation method, including the following steps:

[0048] 1. Preparation of SHB: PDMS and superhydrophobic nano-silica (model: Aerosil R202) were added to an appropriate amount of n-hexane at a mass ratio of 5:3 and stirred evenly to obtain a spraying solution. The ratio of PDMS to curing agent was 10:1. A copper sheet 1 (OS) with a diameter of 5.6 cm was ultrasonically treated in 0.1M hydrochloric acid solution, anhydrous ethanol, and deionized water for five minutes to remove the surface oxide layer. The superhydrophobic spraying solution was evenly sprayed onto the copper sheet using a spray gun, with the pressure maintained within 0.2 MPa and the spraying distance 20 cm. The sprayed copper sheet was then placed in an 80℃ oven for curing for 2 hours to obtain SHB with a superhydrophobic special layer 2 on the surface.

[0049] 2. Preparation of SSHP: 176 pentagonal patterns with a size of 2×2mm were drawn on a laser marking machine and then laser-marked to obtain SSHP.

[0050] 3. Preparation of SSHB: SSHP was placed in a 0.5M CuSO4 electroplating solution as the cathode for electroplating, with the cathode 5 cm away from the anode, and the patterned side facing the anode. Electroplating was performed using a constant current mode of 0.2 A for 90 min, resulting in SSHB with 176 superhydrophilic protrusions.

[0051] 4. After modeling in Solidworks software, a mold is manufactured using 3D printing. The SSHB is placed in the mold and shaped. After folding and shaping, an irregular umbrella structure is formed. The vertex of the irregular umbrella structure is the center of the copper sheet. The irregular umbrella structure includes eight first ridges 4 evenly spaced around the vertex. The first ridges 4 all extend from the center of the copper sheet to the same side of the copper sheet and have the same angle with the original copper sheet plane. A second ridge 5 is set between each two adjacent first ridges 4. The second ridges 5 all extend from the center of the original copper sheet to the same side of the original copper sheet and have the same angle with the original copper sheet plane. The adjacent first ridges 4 and second ridges 5 are connected by a plane, finally forming an irregular umbrella structure. The first ridges 4 and second ridges 5 are all located on the same side of the original copper sheet plane, and the angle between the first ridge 4 and the original copper sheet is 30°, and the angle between the second ridge 5 and the original copper sheet is 20°, resulting in the fog collector SUSHB.

[0052] The tests involved in this embodiment are as follows:

[0053] Mist collection test: The prepared sample was fixed on a bracket opposite the mist outlet, perpendicular to the horizontal plane, for testing. Droplets detached from the surface under gravity and fell into the collection container. The distance between the sample and the mist outlet was 12 cm. The distance between the sample and the collection container was 15 cm. Additionally, another similar water collection container must be placed simultaneously to eliminate the influence of external mist and wind on the test results. The flow rate and rotation speed of the commercial humidifier used were 0.056 g / s. -1 and 25cm s -1 The experiment was conducted at a temperature of 25℃ and a relative humidity of 90%. One measurement cycle lasted 15 minutes, and the water collection rate was obtained by averaging five identical samples. The samples tested were: 1. Original copper sheet (OS); 2. SHB; 3. SSHP; 4. SSHB; 5. SUSHB; 6. Original copper sheet after mold molding; 7. SHB after mold molding. The capture, aggregation, and detachment of droplets during the fog collection process were recorded using a high-speed camera on the original copper sheet, SHB, SSHP, SSHB, and SUSHB. The samples, similarly molded...

[0054] Electrodeposition test: SSHP was placed in the electrolyte for electroplating. Every 20 minutes, the plates were removed and the contact angles between the superhydrophobic region and the hydrophilic patterned region were measured using a contact angle meter. The total electroplating time was 2 hours. The surface of the superhydrophobic region after 2 hours of electroplating was characterized using FESEM.

[0055] UV irradiation test: The SSHB was placed in a sealed chamber with a UV lamp, with the sample 15cm away from the UV lamp. The sample was taken out and the change in contact angle was measured after every 2 hours of UV irradiation. The total irradiation time was 12 hours.

[0056] Abrasion resistance test: The SHB sample was placed on 400-grit sandpaper, and a 4×4 cm² glass slide was placed on top of the sample, along with a 200g weight. The glass slide was used to distribute the weight evenly across the sample surface. The SHB sample was moved horizontally on the sandpaper under external force, and the change in the contact angle was measured every 10 cm of movement.

[0057] Sand impact test: In the constructed test environment, the SHB was placed on a bracket, and sand was poured over it from 25cm above to wash the sample surface. After each 200g of sand was poured over, the SHB was removed, and the surface contact angle was measured after removing the residual sand with deionized water. A total of ten washes were performed.

[0058] Acid and alkali resistance test: 5 μL of liquid with pH value between 1 and 14 was dropped onto the SHB sample, and the effect of the pH value of the liquid on the contact angle of the SHB sample was measured and analyzed.

[0059] Figures 3-6As shown in Figure 12, the surface of the SUSHB fog collector has both superhydrophobic regions and pentagonal superhydrophilic protrusions. Water mist condenses into droplets at the hydrophilic protrusions and falls off, then rolls rapidly through the superhydrophobic regions, improving fog collection efficiency. The SUSHB fog collector has the best fog collection effect because its multiple circumferential folds increase the collision of the fog flow within the collector, enhancing its fog capture capability. Furthermore, it is unaffected by the direction of the fog flow; regardless of the direction from which the fog flow originates, it maintains excellent fog collection performance.

[0060] like Figure 7 As shown, with the increase of electrodeposition time, the contact angle of the hydrophilic region becomes smaller and the hydrophilicity becomes better, while it has almost no effect on the hydrophobic region.

[0061] like Figure 8 As shown, with the extension of UV irradiation time, the contact angle between the hydrophilic and hydrophobic regions of SSHB changes very little, indicating that SSHB has good UV resistance.

[0062] like Figures 9-10 As shown, the SHB surface still exhibits high hydrophobicity after several impacts from sand and abrasive water, indicating that the superhydrophobic coating has a strong bond with the copper sheet surface.

[0063] like Figure 11 As shown, after treatment with acidic and alkaline solutions, the contact angle of SHB with water hardly changed, indicating that the superhydrophobic coating on the surface of SHB has good acid and alkali resistance.

[0064] Example 2

[0065] This embodiment provides a fog collector, the preparation method of which is basically the same as that of Embodiment 1, except that in step 2, the number of patterns drawn is 144.

[0066] Example 3

[0067] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the pattern drawn is circular.

[0068] Example 4

[0069] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the pattern drawn is triangular.

[0070] Example 5

[0071] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the pattern drawn is a quadrilateral.

[0072] Example 6

[0073] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the pattern drawn is hexagonal.

[0074] Examples 2-6 were subjected to mist collection tests (using the same methods as in Example 1) to investigate the effect of the shape of the superhydrophilic protrusion on the mist collection efficiency. Figure 13 As shown, the SSHB with a pentagonal protruding hydrophilic structure has the best collection efficiency. The reason for the high water collection efficiency of the pentagon is that its five sharp corners can serve as water nucleation sites, accelerating the growth and detachment of droplets. However, the corners of the hexagon are relatively dense, making it easy for droplets to stick together and not detach easily, so it does not significantly improve the fog collection efficiency.

[0075] Example 7

[0076] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the number of patterns drawn is 108.

[0077] Example 8

[0078] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the number of patterns drawn is 208.

[0079] Example 9

[0080] This embodiment provides a fog collector, the preparation method of which is basically the same as that of embodiment 2, except that in step 2, the number of patterns drawn is 240.

[0081] Examples 1, 2, and 7-9 were subjected to mist collection tests (using the same methods as in Example 1) to investigate the effect of the density of superhydrophilic protrusions on mist collection efficiency. Figure 13 As shown, the collection efficiency is optimal when the number of superhydrophilic protrusions on the mist collector is 176. This indicates that the ratio of the hydrophilic region area to the hydrophobic region area of ​​the mist collector provided in Example 1 is most suitable. If the hydrophilic region area is too small, it is not conducive to droplet formation; if the hydrophobic region area is too small, it is not conducive to droplet rolling.

[0082] Example 10

[0083] This embodiment provides a mist collector, the preparation method of which is basically the same as that of Embodiment 1. The difference is that in step 4, after the SSHB is plasticized, the angle between the first ridge of the mist collector and the original copper sheet is 15°, and the angle between the second ridge and the original copper sheet is 20°.

[0084] Example 11

[0085] This embodiment provides a mist collector, the preparation method of which is basically the same as that of Embodiment 1. The difference is that in step 4, after the SSHB is plasticized, the angle between the first ridge of the mist collector and the original copper sheet is 45°, and the angle between the second ridge and the original copper sheet is 20°.

[0086] Example 12

[0087] This embodiment provides a mist collector, the preparation method of which is basically the same as that of Embodiment 1. The difference is that in step 4, after the SSHB is plasticized, the angle between the first ridge of the mist collector and the original copper sheet is 60°, and the angle between the second ridge and the original copper sheet is 20°.

[0088] Examples 1 and 10-12 were subjected to mist collection tests (the test method was the same as in Example 1), such as... Figure 14 As shown, the angle between the second ridge and the original copper sheet plane is fixed at 20°, and the inclination angle of the first ridge varies from 15° to 60°. When the inclination angle is 30°, the water collection efficiency of the device is optimal.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A high efficiency mist collector that is not affected by the direction of the mist flow, characterized in that, The fog collector takes a copper sheet (1) as a base material, the surface of the copper sheet is provided with a super-hydrophobic coating (2), and a plurality of super-hydrophilic protruding points (3) are arranged on the super-hydrophobic coating. The copper sheet (1) is formed into a special umbrella surface structure through axial punching and folding, the vertex of the special umbrella surface structure is the center of the copper sheet (1), the special umbrella surface structure comprises a plurality of first edge lines (4) which are uniformly and evenly arranged around the vertex, the first edge lines (4) are all led out from the center of the copper sheet (1) to the same side of the copper sheet and have the same angle with the original copper sheet plane; a second edge line (5) is arranged between every two adjacent first edge lines (4), the second edge line (5) is all led out from the center of the original copper sheet to the same side of the original copper sheet and has the same angle with the original copper sheet plane; the adjacent first edge line (4) and the second edge line (5) are connected by a plane, and finally the special umbrella surface structure is formed, the first edge line (4) and the second edge line (5) are all located on the same side of the original copper sheet plane, and the first edge line (4) and the second edge line (5) have different angles with the original copper sheet plane. The fog collector is prepared through the following steps: 1) polydimethylsiloxane and super-hydrophobic nano-silicon dioxide are added into n-hexane and uniformly mixed, then a curing agent is added to obtain a super-hydrophobic spraying liquid; a copper sheet is sequentially immersed in a hydrochloric acid solution, anhydrous ethanol and deionized water through ultrasonic immersion, then the super-hydrophobic spraying liquid is sprayed on the surface of the copper sheet, and the copper sheet is cured under constant temperature conditions to obtain an SHB; 2) a plurality of marks are formed on the surface of the SHB through laser drawing to obtain an SSHP; 3) the SSHP is placed in a CuSO4 solution as a cathode for electroplating, one side with the pattern marks is opposite to an anode to obtain an SSHP with a plurality of super-hydrophilic protruding points (3); 4) the SSHP is placed in a mold for plastic forming to obtain a fog collector SUSHB.

2. The high efficiency mist collector, according to claim 1, is not affected by the direction of the mist flow, characterized in that, The shape of the super-hydrophilic protruding point (3) comprises a circle, a triangle, a quadrangle, a pentagon and a hexagon.

3. The high efficiency mist collector, according to claim 2, is not affected by the direction of the mist flow, characterized in that, The average diameter of the super-hydrophilic protruding points (3) is 1-3 mm, and the setting density is 4-10 per cm 2 .

4. The high efficiency mist collector, according to claim 1, is not affected by the direction of the mist flow, wherein The angle of the first edge line (4) with the original copper sheet plane is 15-60°, and the angle of the second edge line (5) with the original copper sheet plane is 15-60°.

5. A method of manufacturing a high efficiency fog collector that is not affected by the direction of the fog flow according to any one of claims 1-4, characterized in that, The method comprises the following steps: 1) polydimethylsiloxane and super-hydrophobic nano-silicon dioxide are added into n-hexane and uniformly mixed, then a curing agent is added to obtain a super-hydrophobic spraying liquid; a copper sheet is sequentially immersed in a hydrochloric acid solution, anhydrous ethanol and deionized water through ultrasonic immersion, then the super-hydrophobic spraying liquid is sprayed on the surface of the copper sheet, and the copper sheet is cured under constant temperature conditions to obtain an SHB; 2) a plurality of marks are formed on the surface of the SHB through laser drawing to obtain an SSHP; 3) the SSHP is placed in a CuSO4 solution as a cathode for electroplating, one side with the pattern marks is opposite to an anode to obtain an SSHP with a plurality of super-hydrophilic protruding points (3); 4) the SSHP is placed in a mold for plastic forming to obtain a fog collector SUSHB.

6. The method of claim 5, wherein the high efficiency fog collector is prepared by the steps of: In the step 1), the mass ratio of polydimethylsiloxane to super-hydrophobic nano-silicon dioxide is 5-8:3-6, and the mass ratio of polydimethylsiloxane to the curing agent is 7-10:

1.

7. The method for preparing a high-efficiency fog collector unaffected by the direction of fog flow according to claim 5, characterized in that, In the step 1), the spraying pressure is 0.2-0.5 MPa, and the spraying distance is 20 cm.

8. The method for preparing a high-efficiency mist collector unaffected by the direction of mist flow according to claim 5, characterized in that, The step 1) is carried out at a curing temperature of 80 ℃ for 2 h.

9. The method for preparing a high-efficiency fog collector unaffected by the direction of fog flow according to claim 5, characterized in that, The step 3) is carried out at a plating setting of 0.2 A constant current mode for 90 min.

10. The method for preparing a high-efficiency mist collector unaffected by the direction of mist flow according to claim 5, characterized in that, The step 3) is carried out at a CuSO4 solution concentration of 0.5 M.

Images