A three-dimensional self-driven underwater air flow control system, preparation method and application

Abstract

The present invention discloses a three-dimensional self-driven underwater gas flow control system, which relates to the technical field of underwater gas flow control. The underwater gas flow control system provided by this application can achieve the transmission and manipulation of trace gases at the micro level, so that some new functions and applications that cannot be achieved by traditional liquid microfluidics can be realized. Aiming at the deficiencies of two-dimensional gas flow control systems, a new strategy for constructing a three-dimensional self-driven underwater gas flow control system by combining traditional Chinese weaving techniques and superhydrophobic metal wires and utilizing the Laplace pressure difference inside bubbles is proposed. Using traditional Chinese weaving techniques, the two ends of the superhydrophobic metal wire are curled into disk shapes of different sizes. When the formed framework is immersed in water, the disk structure and the connecting metal wire will be wrapped by a layer of trapped air, thus forming a connected gas flow control system.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater air flow control, and specifically relates to a three-dimensional self-driven underwater air flow control system. Background Art

[0002] Microfluidic technology uses microchannels to process or manipulate trace amounts of liquids and has been widely applied in modern scientific and technological fields such as high-throughput chemical detection, biological analysis, cell manipulation, drug screening, and medical monitoring and examinations. Traditional microfluidic technology mainly focuses on processing and manipulating liquids and rarely pays attention to gases. Since many chemical reactions, analysis, and detection objects involve gases, the transportation and processing of trace gases is a technology with great potential.

[0003] Inspired by the biological characteristics of nature such as lotus leaves, researchers use various special wettability functional surfaces to manipulate droplets or bubbles and apply special wettability surfaces to microfluidic systems to manipulate microfluids. According to the different water contact angles (WCAs) of liquids on solid surfaces, special wettability surfaces can define WCAs in the ranges of 0° < θ < 10°, 10° < θ < 90°, 90° < θ < 150°, and 150° < θ < 180° as superhydrophilic, hydrophilic, hydrophobic, and superhydrophobic, respectively. It should be noted that usually, hydrophilicity corresponds to gas-phobicity, and hydrophobicity corresponds to gas-philicity. Similarly, the wetting behavior between solids and gases can be defined as supergas-phobic, gas-phobic, gas-philic, and supergas-philic in turn. Special wettability surfaces can not only precisely manipulate droplets and gases, but also efficiently mix fluids, improve analysis efficiency and accuracy, and have advantages such as reducing the energy consumption and cost of microfluidic systems. Therefore, special wettability surfaces can play an important role in the field of microfluidics.

[0004] In recent years, the advantages of widely available processable materials and the ability to finely design micro-nano structures have made femtosecond lasers an effective tool for fabricating various superwetting microstructured surfaces. Therefore, using femtosecond lasers to regulate the surface wettability of materials to design underwater microfluidic systems has broad development prospects. Moreover, the patent with the publication number CN209445061U provides a gas transmission system, including: a gas tank having a plurality of gas storage chambers for storing gases; a plurality of chambers; a gas transmission pipe, one end of which is connected to the plurality of gas storage chambers, and the other end is connected to the plurality of chambers. The gas transmission pipe includes: a plurality of first gas transmission pipes, one end of each of the plurality of first gas transmission pipes is connected to the plurality of gas storage chambers in a one-to-one correspondence; a second gas transmission pipe, one end of which is connected to the other ends of the plurality of first gas transmission pipes, and the other end of the second gas transmission pipe is connected to the plurality of chambers. At least a part of the inner diameter of the second gas transmission pipe is larger than the inner diameter of the first gas transmission pipe. However, its structure is complex and the transmission is inconvenient. Based on this, a solution is provided. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art;

[0006] To this end, the present invention proposes a three-dimensional self-driven underwater air flow control system, comprising:

[0007] At least one input disk with a diameter of a;

[0008] At most one output disk with a diameter > a or at least one output disk with a diameter of a;

[0009] The output disk is connected to at least one input disk through a connecting line;

[0010] The input disk, the output disk and the connecting line are all made of strands formed by multiple metal wires wound around each other;

[0011] The surface of the metal wire is covered with laser-induced nanostructures.

[0012] Furthermore, the strand is made of two metal wires wound around each other; the metal wire is made of 304 stainless steel and has a diameter of 100 - 500 μm.

[0013] Furthermore, the input disk and the output disk are in a planar spiral shape wound by strands.

[0014] Furthermore, the nanostructures are obtained by the following method:

[0015] Clean the strands with alcohol and deionized water for ten minutes respectively;

[0016] Then, use femtosecond laser to ablate the surface of the strands, so as to form a layer of covering nanostructures on the surface of the strands.

[0017] A preparation method of a three-dimensional self-driven underwater air flow control system, which specifically comprises the following steps:

[0018] Perform laser ablation on the surface of the strands obtained by winding multiple metal wires around each other, and then connect the ablated substrate to a polyimide double-sided adhesive tape, and perform constant temperature heating, the heating temperature is 75°C - 300°C, and the heating time is 10 - 300 min;

[0019] Coil the strands into at least one input disk with a diameter of a, and at most one output disk with a diameter > a or at least one output disk with a diameter of a;

[0020] The output disk is connected to at least one input disk through strands.

[0021] Furthermore, the strand is obtained by winding two metal wires made of 304 stainless steel around each other, and the diameter of the metal wire is 100 - 500 μm.

[0022] Application of a three-dimensional self-driven underwater gas flow control system, where the aforementioned gas flow control system is used for three-dimensional transmission of gas underwater.

[0023] Further, when there is an output disk with a diameter > a, gas is input from at least one input disk, and is transmitted through the strand part or all to the output disk with a diameter > a. Here, "part" means that the transmitted gas is at least more than half of the original gas, and as the diameter of the output disk increases, the transmitted gas increases until complete transmission.

[0024] Further, when the diameters of the input disk and the output disk are the same, the gas received by the input disk is evenly divided between the input disk and the output disk through the strand.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The underwater gas flow control system provided by the present invention can achieve the transmission and manipulation of trace gases at the microscopic level, so it can realize some new functions and applications that cannot be achieved by traditional liquid microfluidics. Aiming at the deficiencies of two-dimensional gas flow control systems, a new strategy for constructing a three-dimensional self-driven underwater gas flow control system by combining traditional Chinese weaving techniques and superhydrophobic metal wires using the Laplace pressure difference inside bubbles is proposed. Using traditional Chinese weaving techniques, the two ends of the superhydrophobic metal wires are curled into disk shapes of different sizes. When the resulting skeleton is immersed in water, the disk structure and the connecting metal wires will be wrapped by a layer of trapped air, thus forming a connected gas flow control system. Brief Description of the Drawings

[0027] Figure 1 Schematic diagram of the femtosecond laser processing system mentioned in the present invention;

[0028] Figure 2-a Schematic diagram of femtosecond laser processing of a twisted stainless steel wire;

[0029] Figure 2-b Scanning electron microscope image of the laser-induced microstructures on the surface of the twisted stainless steel wire;

[0030] Figure 2-c Schematic diagram of the contact state between the underwater gas flow control system of the present invention and the water environment;

[0031] Figure 3-a Top view of the skeleton structure of the gas flow control system prepared by traditional Chinese weaving techniques;

[0032] Figure 3-b Gas transmission state change diagram of the underwater gas flow control system structure with arch connection;

[0033] Figure 3-c Gas transmission state change diagram of the underwater gas flow control system structure with spiral connection;

[0034] Figure 3-d Graph of the change of the gas shape in the input / collection area over time during the gas self-driven transmission process;

[0035] Figure 3-e Graph of the change of the gas volume in the input area over time;

[0036] Figure 3-f Schematic diagram of the influence of the length (L) of the connecting line between the collection area and the input area on the gas transmission process;

[0037] Figure 3-g Schematic diagram of the influence of the area ratio (η) between the collection area and the input area on the gas transmission process;

[0038] Figure 3-h Schematic diagram showing the physical mechanism of gas self-driven transmission in the designed underwater air flow control system;

[0039] Figure 3-i 45° inclined view of the framework structure of the air flow control system prepared by traditional Chinese weaving technology;

[0040] Figure 4-a Graph of the change of the anti-buoyancy gas transmission state when the air flow control system is tilted downward;

[0041] Figure 4-b Graph of the change of the self-driven gas transmission state along the arched connecting line;

[0042] Figure 4-c Graph of the change of the self-driven gas transmission state along the spiral connecting line;

[0043] Figure 4-d Graph of the change of the independent gas transmission state when two staggered transmission lines do not contact;

[0044] Figure 4-e Graph of the change of the gas transmission state when different air flow control systems are connected together by simple contact;

[0045] Figure 4-f Graph of the change of the state of the underwater air flow control system for gas separation;

[0046] Figure 4-g Graph of the change of the state of the underwater air flow control system for gas merging;

[0047] Figure 4-h Graph of the change of the micro-reaction state between hydrogen and oxygen achieved on a simple underwater air flow control design. Detailed implementation method

[0048] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0049] Please refer to Figure 1 、 Figure 2-a 、 Figure 2-b 、 Figure 2-c as shown; the present application provides a three-dimensional self-driven underwater air flow control system, including:

[0050] At least one input disk with a diameter of a;

[0051] At most one output disk with a diameter > a or at least one output disk with a diameter of a;

[0052] The output disk is connected to at least one input disk through a connecting line;

[0053] The input disk, output disk and connecting line are all made of strands formed by winding multiple metal wires around each other;

[0054] The surface of the metal wire is covered with nanostructures induced by laser.

[0055] Of course, the present application also provides a preparation method for a three-dimensional self-driven underwater air flow control system, and the method specifically includes the following steps:

[0056] Step 1: Wind two fine metal wires made of 304 stainless steel with a diameter of 100 - 500 μm around each other to form a twisted metal wire, and clean it with alcohol and deionized water for ten minutes respectively;

[0057] Step 2: As Figure 1 shown, use a femtosecond laser processing system to perform femtosecond laser ablation processing on the surface of the twisted metal wire. During the laser ablation process, the twisted metal wire will gradually rotate, so that the entire surface of the metal wire is covered with nanostructures induced by laser. The femtosecond laser processing parameters are a scanning power of 50 - 500 mw, a scanning speed of 1 - 20 mm / s, and a scanning pitch of 0.01 - 0.04 mm. The processing process is as Figure 2-a shown;

[0058] Step 3: Connect the femtosecond laser processed twisted metal wire to a PI double-sided tape and send it into an electrothermal constant temperature drying oven for heat treatment. The PI double-sided tape is a polyimide double-sided tape, and the heating parameters are a heating temperature of 75°C - 300°C and a heating time of 10 - 300 min;

[0059] Step 4: Use traditional Chinese weaving techniques to curl the two ends of the twisted metal wire that has undergone femtosecond laser processing and heat treatment into disc shapes with different radii, and leave a connecting wire with a certain distance between the two discs;

[0060] Of course, in specific implementation, disc shapes with diameters of 3 mm and 8 mm can be used respectively, and the distance between the connecting wires of the two discs is 20 mm. The structure is as Figure 3-a , Figure 3-i shown.

[0061] Of course, a three-dimensional self-driven underwater airflow control system provided by this application can be applied to self-driven gas transmission;

[0062] As Figure 3-b shown, it shows the gas transmission ability of the designed basic airflow control system in water medium;

[0063] The left circular area of the basic airflow control system is the input area, the radius r1 of the input area is 1.5 mm, and the right circular area is the collection area, the radius r2 of the collection area is 4 mm; the input area is the input disc mentioned above, and the collection area is also the output disc mentioned above;

[0064] As Figure 3-d shown, when the bubble is released into the input area, its volume decreases rapidly;

[0065] In addition, the gas gradually bulges in the collection area, indicating that the gas has been successfully transported from the input area to the target area along the thin superhydrophobic connecting wire; when the gas of the first bubble is completely transported away, the gas of the subsequently injected bubbles can also be successfully transported to the large circular area, and the gas in the collection area continues to expand; the entire gas transport process is spontaneous and does not require additional energy input; on the contrary, as Figure 3-c shown, when the diameter of the input circular area is larger than the diameter of the collection area, and gas is added to the larger circular area, the injected gas cannot be transported; these results indicate that under the action of the Laplace pressure difference inside the bubble, the gas can be self-driven from the smaller circular area to the larger circular area along the superhydrophobic connecting wire;

[0066] As Figure 3-d and Figure 3-e shown, during the self-driven gas transport process, the volume of the gas injected into the input area gradually decreases over time until it approaches zero, while the volume of the gas in the collection area gradually increases; Figure 3-g compares the gas transport processes of airflow control systems with different area ratios ( ) between the collection area and the input area. The larger the area difference between the collection area and the input area, that is, the larger the ratio, the more conducive to the spontaneous transport of gas. The length L of the connecting wire between the input area and the collection area also has an important influence on the gas transport process, as Figure 3-f。The longer the transmission distance, the slower the gas flow rate, because more fluid resistance needs to be overcome during the transmission process.

[0067] Figure 3-h Reveals the physical mechanism of self-driven gas transmission in the designed air flow control system. In water, since water cannot wet the laser-induced superhydrophobic microstructures, there is a thin layer of air around the superhydrophobic metal wire skeleton. The stagnant gas channels along the gaps of the twisted wires connect the stagnant air films above the input and collection areas. When a small bubble is injected into the input area, due to the restrictive effect of the wettability difference, the gas will be confined on the superhydrophobic / superhydrophilic circular substrate. The gas forms a hemispherical shape in this area, and the bottom of the bubble overlaps with the disk of the twisted wire. There is usually a pressure difference on both sides of the gas-liquid interface, called the Laplace pressure. When a small bubble is sent into the input area of the designed air flow control system, there is a pressure difference between the bubble in the input area and the stagnant gas film in the collection area. Due to the existence of the connecting gas channels, the gas with a higher internal pressure will flow along the pressure gradient to the area with the lowest pressure until the system reaches hydrodynamic equilibrium, i.e., the pressures are equal. Therefore, the Laplace pressure inside the small bubble can provide the driving force for the designed underwater air flow control device.

[0068] Self-driven gas transmission enables the designed air flow control structure to achieve complex gas transportation functions in three-dimensional space; the specific applications are as follows:

[0069] I. Gas delivery on demand:

[0070] When the basic air flow control device with a connection line of 20 mm is tilted downward, the gas injected into the upper input area can also spontaneously transfer to the lower collection area, as Figure 4-a shown. The entire downward delivery process overcomes the buoyancy of the gas. Even if the 30-mm connection line is vertically bent into a three-dimensional arch, as Figure 4-b or the 80-mm connection line is twisted into a more complex spiral shape, as Figure 4-c shown, the air flow control system still supports spontaneous gas delivery. Due to the characteristics of three-dimensional gas transmission, as long as the two staggered gas transmission lines of the basic air flow control system and the air flow control system with the connection line bent and raised do not touch, i.e., one line passes through the other line from above, they can independently transmit gas without interfering with each other. As Figure 4-d shown, the gas injected into area A1 is finally transmitted to area A2; subsequently, the gas injected into area B1 completely flows to area B2. This function of transferring gas from one side of the gas pipeline to the other side is difficult to achieve through a two-dimensional air flow control system;

[0071] Two air flow control systems with the connection lines bent and raised can also be simply connected together by contact. As Figure 4-e, Two misaligned air flow control systems with an angle of approximately 90° are superimposed by making their midpoints of the connecting lines contact each other. Each of the two ends of one air flow control system has two small circular areas A1 and A2 with the same diameter of 3 mm; while the other system has a small circular area B1 with a diameter of 3 mm and a large circular area B2 with a diameter of 8 mm. When small bubbles are injected into area A1, the gas will eventually bulge in area B2, indicating that the gas can be transported in different underwater air flow control systems, A1→B2.

[0072] II. Gas splitting and gas merging;

[0073] By combining different air flow control structures, various gas transportation functions can be achieved. For example, Figure 4-f shows a superimposed system composed of two identical air flow control units, each of which consists of two small circular ends with a diameter of 3 mm and a raised connecting line with a spacing of 20 mm. This combined system has the ability to split gas. When bubbles are injected into any of the circular areas, the gas will be transported to other circular areas and bulge evenly. The input gas is successfully divided into four equal parts. As Figure 4-g shown, if several small circular areas with a diameter of 3 mm and a raised connecting line of 15 mm are connected to a large circular area with a diameter of 8 mm, the gas in the bubbles injected into each small circular area will eventually flow to the largest circular area, gathering the input gas from different directions, and this system can achieve gas merging or gas collection. This system can also achieve the mixing of different types of gases, just by injecting these gases into different input areas.

[0074] III. Application of gas / gas microchemical reaction based on air flow control;

[0075] As a proof-of-concept application, Figure 4-h shows an underwater air flow control system composed of two small circular areas with a diameter of 3 mm, a large circular area with a diameter of 8 mm, and a connecting line of 15 mm between the large and small circles to achieve microreactions between different gases.

[0076] Step 1: Inject four 10 μL H2 bubbles into the left small circular input area successively. The hydrogen in the bubbles will transfer to the collection area of the system, i.e., the large circular area in the figure.

[0077] Step 2: Inject two 10 μL O2 bubbles into the right small circular input area successively. The oxygen will also flow to the collection area, and a large gas mass composed of hydrogen and oxygen is formed in the collection area.

[0078] Step 3: Use the electric flame generated by the piezoelectric ceramic to ignite the mixed gas, and the mixed gas will instantaneously undergo a micro-explosion. This microreaction rapidly consumes hydrogen and oxygen, 2H2 + O2 → 2H2O; resulting in a sharp collapse of the mixed gas bubbles.

[0079] This indicates that the prepared gas flow control system can be used for gas / gas microchemical reactions.

[0080] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical method of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A three-dimensional self-driven underwater airflow control system, characterized in that: include: at least one input disk of diameter a; At most one output disk with diameter > a or at least one output disk with diameter a; The output disk is connected to at least one input disk via a connecting line; The input disk, output disk and connecting wire are all made of strands formed by winding a plurality of metal wires with each other; The surface of the wire is covered with laser-induced nanostructures.

2. A three-dimensional self-driven underwater airflow control system according to claim 1, characterized in that: The strands are made of two metal wires twisted together; the metal wires are made of 304 stainless steel and have a diameter of 100-500μm.

3. A three-dimensional self-driven underwater airflow control system according to claim 1, characterized in that: The input disk and the output disk are in a planar spiral shape formed by winding the strands.

4. A three-dimensional self-driven underwater airflow control system according to claim 1, characterized in that: The nanostructures were obtained by: Clean the strands with alcohol and deionized water for ten minutes each; Then, a femtosecond laser is used to ablate the surface of the strands, thereby forming a covering nanostructure on the surface of the strands.

5. A method for preparing a three-dimensional self-driven underwater airflow control system, characterized in that: The method specifically comprises the following steps: Laser ablation is performed on the surface of a strand obtained by winding a plurality of metal wires, and then the ablated substrate is connected to a polyimide double-sided tape and heated at a constant temperature of 75°C-300°C and a heating time of 10-300 minutes; crimping the strands into at least one input disk with a diameter a, and at most one output disk with a diameter > a or at least one output disk with a diameter a; The output disk is connected to at least one input disk via strands.

6. The method for preparing a three-dimensional self-driven underwater airflow control system according to claim 5, characterized in that: The strands are obtained by winding two 304 stainless steel wires with each other, and the diameter of the wires is 100-500 μm.

7. Application of a three-dimensional self-driven underwater airflow control system, characterized in that: The system according to any one of claims 1 to 4 is used for three-dimensional transmission of gas underwater.

8. The application of a three-dimensional self-driven underwater airflow control system according to claim 7, characterized in that: When there is an output disk with a diameter > a; The gas is input from at least one input disk and is partially or completely transmitted to the output disk with a diameter > a through the strands.

9. Application of a three-dimensional self-driven underwater airflow control system according to claim 8, characterized in that: When there is an output disk with a diameter greater than a, gas is input from at least one input disk and partially or completely transmitted to the output disk with a diameter greater than a through the strands. Here, partially means that the transmitted gas is at least more than half of the original gas, and as the diameter of the output disk increases, the transmitted gas increases until it is completely transmitted.

10. The application of a three-dimensional self-driven underwater airflow control system according to claim 8, characterized in that: When the diameters of the input disk and the output disk are the same, the gas received by the input disk is evenly divided between the input disk and the output disk through the strands.

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