Wettability mixed surface directed transport fog collection apparatus and method

Abstract

This invention discloses a wettable hybrid surface directional transport fog collection device and method. The device includes: an aluminum alloy substrate and a honeycomb and cactus spine coupled biomimetic surface on the aluminum alloy substrate; the honeycomb and cactus spine coupled biomimetic surface is composed of superhydrophobic and superhydrophilic regions; the superhydrophobic region is the aluminum alloy substrate surface after electrochemical etching and fluorosilane modification treatment; the superhydrophilic region is a honeycomb and cactus spine coupled biomimetic pattern formed by laser precision etching on the superhydrophobic region, and the fluorosilane layer in this pattern region is removed and the surface microstructure is reconstructed. Specifically, the pattern consists of multiple wedge-shaped channels of the same size arranged periodically, in a regular arrangement simulating a honeycomb; the wedge-shaped channels have a width gradient from the narrow end to the wide end along the length direction. This invention can achieve full-process optimization from efficient fog droplet capture, rapid condensation, to directional transport and inertial desorption in a two-dimensional plane.

Description

Technical Field

[0001] This invention relates to the field of mist collection technology, specifically to a mist collection device and method for directional transport of wettable mixed surfaces. Background Technology

[0002] Freshwater scarcity is a global crisis, especially in arid and semi-arid regions where access to clean freshwater is particularly difficult. Fog in the atmosphere, as an underutilized freshwater resource, offers a viable solution to this problem through its collection technology.

[0003] Many organisms in nature have evolved to possess the remarkable ability to efficiently extract moisture from fog, providing inspiration for the design of artificial fog collection materials. For example, the Namib desert beetle uses the wettability difference between its hydrophilic protrusions on its back and its hydrophobic background to capture water droplets from fog. Cacti, on the other hand, use the Laplace pressure difference of their conical spines to directionally transport tiny water droplets from the base of the spines to the tip for collection.

[0004] Inspired by these organisms, existing technologies have gradually developed a variety of biomimetic fog-collecting materials. Early on, the focus was mainly on single biomimetic structures, such as patterned wettable surfaces that mimic desert beetles, or conical arrays that mimic cactus spines.

[0005] However, a single biomimetic strategy often has its drawbacks: while mimicking the surface of a beetle can effectively capture fog, the condensed droplets have a strong pinning effect in the hydrophilic region, making it difficult to detach and transport quickly, thus limiting the efficiency of surface renewal and recycling; while mimicking the structure of a cactus spine can enable directional transport, its one-dimensional structure has a limited collection area.

[0006] To address this, this application proposes a wettable mixed surface directional transport fog collection device and method that integrates the advantages of multiple biological structures to achieve full-process optimization in a two-dimensional plane, from efficient fog droplet capture and rapid condensation to directional transport and inertial desorption, thereby solving the aforementioned technical problems. Summary of the Invention

[0007] The main objective of this invention is to provide a wettable mixed surface directional transport fog collection device and method to solve the technical problems mentioned in the background art.

[0008] The present invention solves the above-mentioned technical problems by adopting the following technical solutions: A wettable hybrid surface directional transport fog collection device includes an aluminum alloy substrate and a honeycomb and cactus spine coupled biomimetic surface prepared on the aluminum alloy substrate; The honeycomb and cactus spine coupled biomimetic surface is composed of superhydrophobic and superhydrophilic regions. The superhydrophobic region is the surface of an aluminum alloy substrate that has undergone electrochemical etching and fluorosilane modification, exhibiting superhydrophobicity. The superhydrophilic region is a biomimetic pattern of honeycomb and cactus spines coupled together formed by precise laser etching on the superhydrophobic region. The fluorosilane layer is removed and the surface microstructure is reconstructed in this patterned region, which exhibits superhydrophilicity. The honeycomb and cactus spine coupled biomimetic pattern consists of multiple wedge-shaped channels of the same size arranged periodically, and arranged in a regular pattern to simulate a honeycomb. The wedge-shaped channel has a width gradient from the narrow end to the wide end along its length to simulate the taper effect of cactus spines, thereby creating a Laplace pressure difference within the channel to drive the directional transport of droplets.

[0009] Preferably, the surface of the superhydrophobic region is distributed with an irregular micro-nano-scale rectangular stepped structure formed by electrochemical etching, containing Al, C, O, and F elements, wherein the F element content is 0.77 wt%. The static water contact angle of the superhydrophilic region is set to 0°+ε, where ε is a set of minimum values. The surface of the superhydrophilic region is an irregular micro-nano-scale particle structure formed by laser ablation, containing only Al, C, and O elements, and the main phase is metallic Al.

[0010] Preferably, the geometric parameters of the wedge-shaped channel are: a narrow end width of 0.9 mm, a wide end width of 1.7 mm, a channel height of 6 mm, and a laser etching depth of 0.05 mm.

[0011] Preferably, multiple honeycomb-coupled biomimetic surfaces with cactus spines are combined to form fog collection structures in circular, triangular, rectangular, or inverted triangular shapes. Among these, the fog collection efficiency is highest when combined into a triangular structure, reaching [amount missing]. . Preferably, the fabrication process of the device includes: Step S1. Substrate pretreatment: Select an aluminum alloy plate and perform degreasing, cleaning, and drying treatments in sequence to remove surface oil and impurities; Step S2. Superhydrophobic surface preparation: The pretreated aluminum alloy plate was used as the anode and the copper plate as the cathode. Constant current etching was performed in a 2 mol / L NaCl electrolyte solution with an electrode spacing of 20 mm and a current density of 5 A / cm². 2 The etching time is 8 minutes; After etching, the surface is ultrasonically cleaned with deionized water and dried to obtain a superhydrophilic surface. The surface was immersed in a 1% (w / w) fluorosilane-ethanol solution for 40 min at room temperature, and then removed and placed in a 120℃ oven for 20 min to obtain a superhydrophobic surface. Step S3. Preparation of honeycomb and cactus spine coupled biomimetic surface: The superhydrophobic surface obtained in step S2 is patterned and etched using nanosecond laser direct writing technology. The superhydrophobic aluminum alloy plate is placed at the focal point of the laser processing platform, and the honeycomb and cactus spine coupled biomimetic pattern is drawn by computer control program. The laser parameters are set as follows: power of 50W, wavelength of 1064nm, pulse width of 20ns, pulse frequency of 20kHz, and scanning speed of 500mm / s. Scanning and etching are performed according to the predetermined path, and the etching depth is controlled to be 0.05mm. After etching, the honeycomb and cactus spine coupled biomimetic surface is obtained, which is the high-efficiency fog collection device.

[0012] Preferably, in step S2, the fluorosilane-ethanol solution is prepared by mixing fluorosilane and anhydrous ethanol. The fluorosilane, NaCl, and anhydrous ethanol are all of analytical grade and can be used directly without further purification.

[0013] Preferably, the number of laser etching cycles in step S3 can be adjusted according to actual needs. As the number of etching cycles changes, the fog collection efficiency remains within [the specified range]. Fluctuations within the range remain relatively stable.

[0014] On the other hand, the present invention also discloses a method for collecting fog by directional transport of wettable mixed surfaces, which is implemented based on any of the above-described devices for collecting fog by directional transport of wettable mixed surfaces.

[0015] Preferably, the collection method includes: Step L1. Experimental environment setup and calibration: Set the ambient temperature to 27℃ and the relative humidity to 75% in the controlled environment chamber, and set up a fog collection test system. The fog collection test system in step L1 includes a commercial humidifier for generating a stable fog flow, a rotatable platform for fixing the device and adjusting the tilt angle, a beaker placed below the bottom of the device for collecting the collected liquid, and a high-precision balance for weighing the collected liquid in real time. Step L2. Device installation and parameter adjustment: Fix the wettable mixing surface directional transport mist collection device on the rotatable platform, adjust the axial distance between the surface of the high-efficiency mist collection device and the atomization outlet of the humidifier to a range of 1-11cm, and at the same time adjust the rotatable platform so that the surface of the device is tilted to the horizontal plane at a set angle range of 30°-80°. In step L2, the optimal tilt angle of the high-efficiency fog collection device is set to 50°, and the optimal distance between the high-efficiency fog collection device and the fog outlet is set to 3cm. Under these conditions, the fog collection efficiency reaches its optimal value.

[0016] Step L3. Fog collection and performance characterization: Activate the humidifier to allow the fog flow to contact the surface of the high-efficiency fog collection device, and continuously monitor and record the total weight of droplets falling into the beaker per unit time using a high-precision balance.

[0017] Preferably, after monitoring and recording the total weight of the droplets in step L3, the fog collection efficiency is calculated as follows: the total weight of the droplets collected per unit time is divided by the total area of ​​the honeycomb and cactus spine coupled biomimetic surface in the fog collection device or by the rectangular projected area of ​​the device. Each experimental condition is tested three times to ensure data reliability.

[0018] Preferably, under the experimental conditions of 27°C temperature, 75% relative humidity, 3cm distance between the device and the fog outlet, and 50° tilt angle, the fog collection device in step L3 has a fog collection efficiency of [missing information]. Compared to a single superhydrophobic surface and a wettability hybrid patterned surface composed of rectangular channels, the efficiency is improved by 23.5% and 4.27%, respectively.

[0019] As can be seen from the above technical solution, the present invention provides a device and method for directional transport of mist on wettable mixed surfaces. Compared with the prior art, the present invention has the following advantages: 1. This invention couples the regular arrangement of honeycombs, the wettability gradient of beetles, and the taper effect of cactus spines onto the same two-dimensional surface. The honeycomb arrangement ensures the uniform distribution and high density of droplet capture points. The superhydrophobic substrate facilitates droplet rolling and coalescence and surface cleaning, while the Laplace pressure difference generated by the wedge-shaped channel provides a spontaneous driving force for directional transport of droplets. This effectively solves the problems of droplet pinning and slow transport on traditional wettable mixed surfaces, ultimately optimizing the entire process of droplet "capture-condensation-directional transport-detachment".

[0020] 2. By changing the laser processing parameters and pattern design, the size, density and distribution of the wedge channel can be flexibly adjusted to adapt to different environmental conditions. At the same time, the BPHCSC pattern can be used as a basic unit for two-dimensional infinite expansion and arbitrary shape combination (such as circles and triangles), which greatly facilitates the preparation of large-area, customized devices for practical applications.

[0021] It should be understood that the descriptions in this section are not intended to identify key or essential features of embodiments of the invention, nor are they intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Of course, implementing any product of the invention does not necessarily require achieving all of the advantages described above simultaneously. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the high-efficiency fog collection device for wettable mixed patterned surfaces of the present invention; Figure 2 A schematic diagram of the process for preparing a superhydrophobic (SHB) surface by electrochemical etching according to the present invention; Figure 3 This is a schematic diagram of the structure of the present invention, which integrates the geometric features of honeycomb and cactus spines. Figure 4 A schematic diagram illustrating the nanosecond laser fabrication of a BPHCSC surface according to the present invention; Figure 5 This is a schematic diagram of the continuous transmission channel structure of the present invention with scalability and adjustability at bending angles θ of 0°, 30°, 60° and 90°. Figure 6 This is a schematic diagram of the droplet directional transport test platform of the present invention; Figure 7 This is a schematic diagram of the fog collection system of the present invention; Figure 8 This is a schematic diagram of a bar chart showing the high fog collection efficiency of the BPHCSC combination pattern formed by the present invention in three extended combination patterns: circle, triangle, and rectangle. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] For details in the embodiments, please refer to Figures 1 to 8 .

[0025] In the first embodiment, the wettability-mixed surface directional transport fog collection device proposed in this invention includes an aluminum alloy substrate and a honeycomb and cactus spine coupled biomimetic surface (BPHCSC surface) prepared on the aluminum alloy substrate. (Reference) Figure 1 ; The honeycomb and cactus spine coupled biomimetic surface (BPHCSC surface) is composed of superhydrophobic and superhydrophilic regions. The superhydrophobic region is an aluminum alloy substrate surface that has been electrochemically etched and modified with fluorosilane, exhibiting superhydrophobicity. The superhydrophilic region is a honeycomb and cactus spine coupled biomimetic pattern formed by laser precision etching on the superhydrophobic region. Furthermore, the fluorosilane layer in this patterned region has been removed and the surface microstructure has been reconstructed, exhibiting superhydrophilicity. The honeycomb and cactus spine coupled biomimetic pattern consists of multiple wedge-shaped channels of the same size arranged periodically, and provides capillary force guidance in a regular arrangement structure that simulates a honeycomb. The wedge-shaped channel has a width gradient from the narrow end to the wide end along its length to simulate the taper effect of cactus spines, so as to create a Laplace pressure difference within the channel to drive the directional transport of droplets.

[0026] Furthermore, the geometric parameters of the wedge-shaped channel are: a narrow end width of 0.9 mm, a wide end width of 1.7 mm, a channel height (length) of 6 mm, and a laser etching depth of 0.05 mm. This specific combination of parameters optimizes the Laplace pressure difference, enabling rapid transport of droplets from the narrow end to the wide end without causing droplet breakage or pinning due to excessive pressure.

[0027] In one embodiment, the static water contact angle of the superhydrophobic region is ≥160°, specifically up to 167.98°; its surface is distributed with a large number of irregular micro-nano-scale rectangular stepped structures formed by electrochemical etching, and X-ray energy dispersive spectroscopy (EDS) analysis shows that the surface contains Al, C, O and F elements, of which the F element content is 0.77wt%, confirming the effective modification of the fluorosilane low surface energy material.

[0028] The static water contact angle of the superhydrophilic region is close to 0°; its surface is an irregular micro-nano-scale particle structure formed by laser ablation. EDS detection shows that the surface contains only Al, C, and O elements, and the main phase is metallic Al, indicating that the fluorosilane layer has been completely removed, exposing a high surface energy oxide layer or metal substrate.

[0029] The aforementioned device couples the regular arrangement of honeycombs, the wettability gradient of beetles, and the taper effect of cactus spines onto the same two-dimensional surface. The honeycomb arrangement ensures the uniform distribution and high density of droplet capture points. The superhydrophobic substrate facilitates droplet rolling and coalescence and surface cleaning, while the Laplace pressure difference generated by the wedge-shaped channel provides a spontaneous driving force for droplet directional transport. This effectively solves the problems of droplet pinning and slow transport on traditional wettable mixed surfaces, ultimately optimizing the entire process of droplet "capture-condensation-directional transport-detachment".

[0030] In one embodiment, multiple honeycomb-coupled biomimetic surfaces with cactus spines are combined to form circular, triangular, rectangular, or inverted triangular fog collection structures to adapt to different environmental wind directions, installation space, and collection efficiency requirements. Among these, the fog collection efficiency is highest when combined into a triangular structure, reaching [amount missing]. .

[0031] Furthermore, the preparation process of this wettable mixed surface directional transport mist collection device includes: Step S1. Substrate pretreatment: Select an aluminum alloy plate (e.g., 5052 aluminum alloy) and perform degreasing, cleaning, and drying treatments in sequence to remove surface oil and impurities; Step S2. Preparation of superhydrophobic surface: A superhydrophobic layer is constructed on the aluminum alloy surface by electrochemical etching combined with fluorosilane modification. Specifically, the pretreated aluminum alloy plate is used as the anode and the copper plate is used as the cathode. The plate is placed in a 2 mol / L NaCl electrolyte for constant current etching. The electrode spacing is 20 mm, the current density is 5 A / cm2, and the etching time is 8 min. After etching, the surface is ultrasonically cleaned with deionized water and dried to obtain a superhydrophilic surface. The surface was immersed in a 1% (w / w) fluorosilane-ethanol solution for 40 min at room temperature, and then removed and placed in a 120℃ oven for 20 min to obtain a superhydrophobic surface. The fluorosilane-ethanol solution is prepared by fluorosilane and anhydrous ethanol. Fluorosilane, NaCl, and anhydrous ethanol are all of analytical grade and can be used directly without further purification. Step S3. Preparation of the honeycomb and cactus spine coupled biomimetic surface (BPHCSC surface): The superhydrophobic surface obtained in step S2 is patterned and etched using nanosecond laser direct writing technology. The superhydrophobic aluminum alloy plate is placed at the focal point of the laser processing platform. The honeycomb and cactus spine coupled biomimetic pattern is drawn by a computer-controlled program. The laser parameters are set as follows: power 50W, wavelength 1064nm, pulse width 20ns, pulse frequency 20kHz, and scanning speed 500mm / s. Scanning and etching are performed according to a predetermined path, and the etching depth is controlled to be 0.05mm. During the etching process, the laser ablates and removes the FAS layer and part of the substrate material in the scanned area, forming a superhydrophilic BPHCSC pattern, while the unscanned areas retain their original superhydrophobic properties, thus obtaining a high-efficiency fog collection device. After etching, the honeycomb and cactus spine coupled biomimetic surface is obtained, which is the high-efficiency fog collection device. The number of laser etching cycles can be adjusted according to actual needs. As the number of etching cycles changes, the fog collection efficiency remains within [the specified range]. The fluctuations within the range remain relatively stable, indicating a high degree of process tolerance.

[0032] In a second embodiment, and furthermore, the present invention discloses a method for collecting directional transport fog on a wettable mixed surface, implemented based on the directional transport fog collection device for a wettable mixed surface described in the above embodiments. The specific collection method includes: Step L1. Experimental environment setup and calibration: In a controlled environment chamber, set the ambient temperature to 27℃ and the relative humidity to 75% to set up a fog collection test system. The fog collection test system here includes a commercial humidifier for generating a stable fog flow (with a fog output of 300 mL / h and an outlet diameter of 2.4 cm), a rotatable platform for fixing the device and adjusting the tilt angle, a beaker placed at the bottom of the device for collecting the collected liquid, and a high-precision balance for weighing the collected liquid in real time. Step L2. Device installation and parameter adjustment: Fix the wettable mixing surface directional transport mist collection device on the rotatable platform, adjust the axial distance between the surface of the high-efficiency mist collection device and the atomization outlet of the humidifier to a range of 1-11cm, and at the same time adjust the rotatable platform so that the surface of the device is tilted to the horizontal plane at a set angle range of 30°-80°. In step L2, the optimal tilt angle of the high-efficiency fog collection device is set to 50°, and the optimal distance between the high-efficiency fog collection device and the fog outlet is set to 3cm. Under these conditions, the fog collection efficiency reaches its optimal value.

[0033] Step L3. Fog collection and performance characterization: Turn on the humidifier to allow the fog to contact the surface of the high-efficiency fog collection device, record the time when the first drop falls, and continuously monitor and record the total weight of droplets falling into the beaker per unit time (e.g., 1 hour) using a high-precision balance. The fog collection device achieved its optimal efficiency under the experimental conditions of 27℃ temperature, 75% relative humidity, 3cm distance between the device and the fog outlet, and 50° tilt angle. The fog collection efficiency was: Compared to a single superhydrophobic surface and a wettability hybrid patterned surface composed of rectangular channels, the efficiency is improved by 23.5% and 4.27%, respectively.

[0034] In addition, after monitoring and recording the total weight of the droplets in step L3, the fog collection efficiency is calculated as follows: the total weight of the droplets collected per unit time is divided by the total area of ​​the honeycomb and cactus spine coupled biomimetic surface in the fog collection device or by the rectangular projected area of ​​the device. Each experimental condition is repeated 3 times to ensure data reliability.

[0035] In the third embodiment, based on the above-described wettable mixed surface directional transport fog collection device and method, the following specific process for preparing the fog collection device is adopted in a further implementation: A. Substrate Pretreatment: Select a 5052 aluminum alloy plate with dimensions of 50mm × 40mm × 2mm. Clean the plate sequentially with acetone, anhydrous ethanol, and deionized water in an ultrasonic cleaner for 10 minutes each to thoroughly remove surface oil and impurities. After cleaning, place the plate in a 60℃ oven to dry for 30 minutes, then remove and cool to room temperature before sealing and storing for later use.

[0036] B. Preparation of superhydrophobic (SHB) surfaces: Electrochemical etching: A pretreated aluminum alloy plate was used as the anode, and a pure copper plate (Cu) was used as the cathode. The two electrodes were placed parallel in the electrolytic cell with a fixed spacing of 20 mm. The electrolyte was a 2 mol / L NaCl aqueous solution. Constant current etching was performed under a DC power supply, with a current density of 5 A / cm² and an etching time of 8 min.

[0037] Post-processing: After etching, the aluminum alloy plate was immediately removed and rinsed with plenty of deionized water to remove residual electrolyte. It was then ultrasonically cleaned in deionized water for 3 minutes to remove any loose etching products. After cleaning, the sample was placed in a 50°C oven and dried for 2 minutes to obtain a superhydrophilic surface with a micro / nano-scale rough structure (static water contact angle close to 0°).

[0038] Low surface energy modification: The dried superhydrophilic aluminum alloy plate was completely immersed in a 1% (w / w) anhydrous fluorosilane (FAS, perfluorodecyltrimethoxysilane) solution in ethanol and sealed for 40 min at room temperature (approximately 25°C). After removal, the surface was gently rinsed with anhydrous ethanol to remove excess physically adsorbed FAS molecules. Subsequently, the sample was heat-treated in an oven at 120°C for 20 min to allow FAS molecules to be firmly grafted onto the surface through chemical bonds. The resulting superhydrophobic surface was thus obtained.

[0039] like Figure 2 As shown, the preparation process of electrochemical etching combined with fluorosilane modification includes: substrate pretreatment → constant current etching in NaCl solution → ultrasonic cleaning and drying → immersion in fluorosilane-ethanol solution at room temperature → heat treatment at 120℃ → obtaining a superhydrophobic surface.

[0040] C. Preparation of superhydrophilic BPHCSC patterns: Laser processing: The superhydrophobic aluminum alloy plate prepared in step 2 is fixed on the worktable of the nanosecond laser processing platform, and the Z-axis is adjusted so that the sample surface is located at the laser focal point. The BPHCSC pattern is drawn using laser control software.

[0041] like Figure 1 and Figure 3 As shown, the pattern consists of an array of multiple periodically arranged wedge-shaped channels.

[0042] The geometric parameters of a single wedge channel are designed as follows: narrow end width Width of the wide end The channel height (length) L = 6mm.

[0043] At this point, the biomimetic pattern design of the honeycomb and cactus spines combines the regular hexagonal arrangement of the honeycomb (ensuring uniform distribution of capture points) with the tapered width gradient of the cactus spines (generating a Laplace pressure difference to drive directional droplet transport). For example... Figure 3 As shown in the figure, the narrow end, wide end, and length direction of the wedge-shaped channel, as well as the arrangement of the periodic array, are illustrated in detail.

[0044] Process parameters: A nanosecond fiber laser was used, with a wavelength of 1064nm, an average power of 50W, a pulse width of 20ns, a repetition frequency of 20kHz, and a scanning speed of 500mm / s. The laser spot was used for single-scan etching along the pattern path, and the etching depth was controlled to 0.05mm based on previous process experiments.

[0045] At this time, as Figure 4 As shown, the process of fabricating a BPHCSC surface using nanosecond laser direct writing technology is as follows: a superhydrophobic aluminum alloy plate is placed at the focal point of a laser processing platform. A computer-controlled laser beam scans along a preset path, ablating and removing the FAS layer and reconstructing the surface microstructure. The scanned area becomes superhydrophilic (forming a wedge-shaped channel pattern), while the unscanned area retains its original superhydrophobic properties. The figure illustrates the laser focal point, the scanning path, and the final patterned surface.

[0046] Forming: After laser scanning, the FAS layer in the scanned area is ablated and removed, and the surface microstructure is reconstructed into an irregular granular structure, exhibiting superhydrophilicity; the unscanned area retains its original superhydrophobicity. Thus, a multi-coupled biomimetic wettability hybrid surface composed of a superhydrophilic BPHCSC pattern and a superhydrophobic background, i.e., a high-efficiency fog collection device, has been successfully fabricated on an aluminum alloy substrate.

[0047] At this point, the surface properties of the prepared sample are characterized, and the following are obtained: Wettability: The static water contact angle of the superhydrophobic region is 167.98° and the roll-off angle is <5°; the static water contact angle of the superhydrophilic pattern region is about 0°, and the water droplet spreads instantly after contact.

[0048] Surface composition: EDS analysis of the superhydrophobic region showed the presence of Al, C, O, and F elements, with F atomic percentage at 0.77%, indicating successful FAS modification. EDS analysis of the superhydrophilic region showed only Al, C, and O elements, with the disappearance of FAS characteristic peaks and Al as the main phase, indicating that the FAS layer had been effectively removed by laser.

[0049] Surface morphology: The superhydrophobic region is an irregular micro-nano-scale rectangular stepped structure; the superhydrophilic region is a micro-nano-scale granular molten recast layer structure formed by laser ablation.

[0050] In the fourth embodiment, based on the above-described wettability-mixing surface directional transport mist collection device and method, further specific implementations utilize... Figure 7 The test system shown was used to test fog collection performance and explore the optimal experimental parameters. The specific fog collection performance testing and optimization process is as follows: Test system setup: A commercial humidifier (mist output 300mL / h), a rotatable platform, a beaker for receiving the humidifier, and a high-precision electronic balance (accuracy 0.1mg) were set up. Figure 7 The layout is shown. The experimental environment was controlled at a temperature of 27℃ and a relative humidity of 75%. During the testing experiment, in order to verify the scalability and adjustability of the pattern, such as... Figure 5 As shown, the present invention also designs continuous transport channel structures with different bending angles θ (0°, 30°, 60°, 90°). Furthermore, in further experiments, experimental results show that even in curved paths, droplets can still achieve directional transport by relying on the Laplace pressure difference of the wedge-shaped channel, thus proving the adaptability of this pattern to complex flow channel designs.

[0051] Distance optimization experiment: The surface of the fixed device is perpendicular to the horizontal plane (tilt angle 0°). The distance between the surface of the device and the atomizing outlet of the humidifier is adjusted to 1, 3, 5, 7, 9, and 11 cm respectively. At each distance, mist water is continuously collected for 1 hour, the balance data is recorded, and the mist collection efficiency (the amount of water collected per unit area per unit time) is calculated.

[0052] Each experiment was repeated 3 times and the average value was taken.

[0053] Furthermore, such as Figure 6 As shown, the droplet-oriented transport test platform includes a high-precision syringe pump, an inclined stage, and a high-speed camera. The BPHCSC surface is fixed on the inclined stage, and a fixed-volume droplet is released at the narrow end of a wedge-shaped channel using a micro-injector. The high-speed camera records the trajectory and time of the droplet's movement from the narrow end to the wide end to quantitatively analyze the transport velocity. This platform verifies the spontaneous directional driving capability of the wedge channel for droplets.

[0054] The results showed that the fog collection efficiency decreased with increasing distance, reaching its highest efficiency at a distance of 1 cm. Taking into account both practical applications and the uniformity of fog distribution, a test distance of 3 cm was selected for subsequent experiments.

[0055] Tilting angle optimization experiment: The distance between the fixed device and the fog outlet is 3cm. The tilt angle (angle with the horizontal plane) of the device is adjusted to 30°, 40°, 50°, 60°, 70° and 80° respectively. The test method is the same as above.

[0056] The results show that the tilt angle has a significant impact on efficiency, and the fog collection efficiency reaches its highest value at a tilt angle of 50°. When the tilt angle is less than 50°, the droplets stay on the surface for too long and detach slowly; when the tilt angle is greater than 50°, the mist is captured on the surface for too short a time and condensation is insufficient.

[0057] Comparative Experiment: Under optimal conditions (distance 3cm, tilt angle 50°), the fog collection efficiency of the BPHCSC surface prepared in this invention was compared with that of the control group (single superhydrophobic surface, hybrid wettability surface composed of rectangular channels). The rectangular channel size is comparable to the contour size of the wedge channel, but it does not have a width gradient. The specific results are shown in Table 1 below: Table 1: Comparison of Fog Collection Efficiency on Different Surfaces

[0058] Based on the data in Table 1 above, the surface efficiency of BPHCSC reaches... Compared to a single superhydrophobic surface ( ) and rectangular channel surface ( This represents an increase of approximately 23.5% and 4.27%.

[0059] This fully demonstrates the crucial role of wedge-shaped channels with gradient widths (cactus spine effect) in improving transportation efficiency.

[0060] Further as Figure 7 As shown, the overall layout of the fog collection test system includes: a controllable environment chamber, a commercial humidifier (with adjustable fog flow direction), a rotatable platform (with fixed devices and adjustable tilt angle), a beaker placed at the bottom of the device (to collect the collected droplets), and a high-precision electronic balance (for real-time weighing). The figure indicates the distance between the device and the fog outlet, the tilt angle θ, and the way the fog flow contacts the surface. This system is used to systematically evaluate the fog collection efficiency of different surfaces under different parameters.

[0061] In the fifth embodiment, based on the above-described wettability-mixed surface directional transport fog collection device and method, individual BPHCSC patterns are used as basic units, and through layout design, they are combined into large-area patterns (with the same total area) of circles, triangles, and rectangles. The same testing method as in the above embodiments (distance 3cm, tilt angle 50°) is used for testing. The results in further specific implementations are as follows: Figure 8 As shown, the triangular combination pattern has the highest fog collection efficiency, reaching [a certain level]. Superior to a circle ( ) and rectangle ( The combination of patterns demonstrates that by optimizing the geometry of the macroscopic patterns, the airflow direction and droplet convergence path can be further adapted to improve collection efficiency, thus confirming the scalability and adjustability advantages of the present invention.

[0062] At this time, as Figure 8 As shown, the bar chart of fog collection efficiency under the same test conditions (distance 3 cm, tilt angle 50°) by combining individual BPHCSC pattern basic units into large-area patterns of circles, triangles, and rectangles shows that the triangular combination pattern has the highest efficiency (91.3 mg·cm⁻¹). - ²·h - ¹), followed by rectangles (86.2 mg·cm⁻¹). - ²·h - ¹), the lowest circular shape (81.2 mg·cm⁻¹) - ²·h - ¹). This indicates that macroscopic geometry has a significant impact on collection efficiency, and the shape can be further optimized to better suit airflow direction and droplet convergence path.

[0063] In summary, this method and apparatus, by changing laser processing parameters and pattern design, can flexibly adjust the size, density, and distribution of the wedge-shaped channels to adapt to different environmental conditions. Furthermore, the BPHCSC pattern can be used as a basic unit for two-dimensional infinite expansion and arbitrary shape combinations (such as circles and triangles), greatly facilitating the fabrication of large-area, customized devices for practical applications. Experimental data shows that the surface fog collection efficiency of the BPHCSC prepared by this invention reaches [a certain level]. Compared to a single superhydrophobic surface and a conventional wettability hybrid pattern surface composed of rectangular channels, the efficiency was significantly improved by approximately 23.5% and 4.27%, respectively. This demonstrates the superiority of multi-coupled biomimetic structures over single or dual biomimetic structures. Ultimately, a multi-coupled biomimetic wettability hybrid surface was successfully constructed. Through meticulous structural design and optimized fabrication processes, it exhibited outstanding performance in the field of mist collection, providing a new and efficient material and solution for addressing water scarcity issues.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0065] Furthermore, it should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of the present invention, the directional indication is only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0066] Furthermore, those skilled in the art should understand that in the actual use of the embodiments of this application, there may be preset thresholds used as the basis for judging the corresponding technical solutions. These thresholds are conventional technical means commonly used in the field to implement functions such as state judgment, condition recognition, and control logic switching. The specific values, setting basis, value selection methods, determination methods, and adjustment rules of the thresholds involved in this technical solution are all conventional technical choices that can be reasonably determined by those skilled in the art based on conventional technical factors such as actual application scenarios, system working states, characteristics of the detection object, hardware performance parameters, and functional requirements, through conventional experiments, calibrations, and debugging. The specific setting and adjustment of the aforementioned thresholds will not cause this technical solution to be unimplementable as a whole, nor will it affect the realization of the core concept and the achievement of the technical effects of this technical solution.

[0067] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, in the embodiments of this invention, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A wettable mixing surface directional transport mist collection device, characterized in that, Includes an aluminum alloy substrate and a honeycomb and cactus spine coupled biomimetic surface prepared on the aluminum alloy substrate; The honeycomb and cactus spine coupled biomimetic surface is composed of superhydrophobic and superhydrophilic regions. The superhydrophobic region is the surface of an aluminum alloy substrate after electrochemical etching and fluorosilane modification. The superhydrophilic region is a honeycomb and cactus spine coupled biomimetic pattern formed by laser precision etching on the superhydrophobic region, and the fluorosilane layer is removed and the surface microstructure is reconstructed in the pattern region. The honeycomb and cactus spine coupled biomimetic pattern consists of multiple wedge-shaped channels of the same size arranged periodically, and arranged in a regular pattern to simulate a honeycomb. The wedge-shaped channel has a width gradient from the narrow end to the wide end along its length.

2. The wettability mixing surface directional transport mist collection device as described in claim 1, characterized in that, The surface of the superhydrophobic region is distributed with irregular micro- and nano-scale rectangular stepped structures formed by electrochemical etching, containing Al, C, O, and F elements, with F content of 0.77 wt%. The static water contact angle of the superhydrophilic region is set to 0°+ε, where ε is a set of minimum values. The surface of the superhydrophilic region is an irregular micro-nano-scale particle structure formed by laser ablation, containing only Al, C, and O elements, and the main phase is metallic Al.

3. The wettability mixing surface directional transport mist collection device as described in claim 2, characterized in that, Multiple honeycomb-coupled biomimetic surfaces are combined to form fog collection structures in circular, triangular, rectangular, or inverted triangular shapes.

4. The wettability mixing surface directional transport mist collection device as described in claim 1, characterized in that, The fabrication process of the device includes: Step S1. Select an aluminum alloy plate and perform degreasing, cleaning, and drying processes in sequence to remove surface oil and impurities; Step S2. Using the pretreated aluminum alloy plate as the anode and the copper plate as the cathode, constant current etching is performed in a 2 mol / L NaCl electrolyte solution with an electrode spacing of 20 mm and a current density of 5 A / cm². 2 The etching time is 8 minutes; After etching, the surface is ultrasonically cleaned with deionized water and dried to obtain a superhydrophilic surface. The surface was immersed in a 1% (w / w) fluorosilane-ethanol solution for 40 min at room temperature, and then removed and placed in a 120℃ oven for 20 min to obtain a superhydrophobic surface. Step S3. Patterned etching is performed on the superhydrophobic surface using nanosecond laser direct writing technology. The superhydrophobic aluminum alloy plate is placed at the focal point of the laser processing platform. A honeycomb and cactus spine coupled biomimetic pattern is drawn by a computer control program. The laser parameters are set as follows: power of 50W, wavelength of 1064nm, pulse width of 20ns, pulse frequency of 20kHz, and scanning speed of 500mm / s. The scanning and etching are performed according to the predetermined path, and the etching depth is controlled to be 0.05mm. After etching, a honeycomb and cactus spine coupled biomimetic surface is obtained.

5. The wettability mixing surface directional transport mist collection device as described in claim 4, characterized in that, In step S2, the fluorosilane-ethanol solution is prepared by mixing fluorosilane and anhydrous ethanol, and the fluorosilane, NaCl, and anhydrous ethanol are all of analytical grade.

6. A method for collecting mist transported directionally on a wettable mixed surface, implemented based on the mist collection device for collecting mist transported directionally on a wettable mixed surface as described in any one of claims 1-5, characterized in that, include: Step L1. Construct a fog collection test system in a controlled environment chamber; Step L2. Fix the wettable mixing surface directional transport mist collection device on a rotatable platform, adjust the axial distance range between the surface of the high-efficiency mist collection device and the atomization outlet of the humidifier, and at the same time adjust the rotatable platform so that the surface of the device is at a set tilt angle range with the horizontal plane. Step L3. Start the humidifier to make the mist flow contact the surface of the high-efficiency mist collection device, and continuously monitor and record the total weight of droplets falling into the beaker per unit time using a high-precision balance.

7. The method for directional transport and collection of mist on a wettable mixed surface as described in claim 6, characterized in that, The fog collection test system in step L1 includes a commercial humidifier for generating a stable fog flow, a rotatable platform for fixing the device and adjusting the tilt angle, a beaker placed below the bottom of the device for collecting the collected liquid, and a high-precision balance for weighing the collected liquid in real time.

8. The method for directional transport and collection of mist on a wettable mixed surface as described in claim 6, characterized in that, In step L2, the tilt angle of the high-efficiency fog collection device is set to 50°, and the optimal distance between the high-efficiency fog collection device and the fog outlet is set to 3cm.

9. The method for directional transport and collection of fog on a wettable mixed surface as described in claim 6, characterized in that, After monitoring and recording the total weight of the droplets in step L3, the fog collection efficiency is calculated as follows: the total weight of the droplets collected per unit time is divided by the total area of ​​the honeycomb and cactus spine coupled biomimetic surfaces in the fog collection device, or divided by the rectangular projected area of ​​the device.

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