Microarray structure surface with low-temperature antifouling and directional icing functions and preparation method of microarray structure surface

Abstract

The invention discloses a low-temperature antifouling and directional icing microarray structure surface and a preparation method thereof, a tile-covering-shaped arrangement structure with an asymmetric groove structure on the surface is prepared, and a substrate of the structure is a wavy base material. In a low-temperature environment, due to the existence of the tile-shaped arrangement structure, water molecules are more easily gathered and nucleated at the edge of the tile-shaped arrangement structure. When the ice core forms an ice bar, the airflow around the tile-shaped arrangement structure begins to flow to the ice core, and a higher atmospheric pressure gradient is generated locally, so that more water vapor flows to ice on the edge of the tile-shaped arrangement structure. And meanwhile, the asymmetric groove structure divides the air flow into smaller intervals, so that the air in the air flow is more easily pushed by the air pressure difference at the two ends of the groove to flow to the edge of the tile-shaped arrangement structure, and the directional icing function is achieved. The workpiece prepared on the basis of the characteristics can be prevented from being covered by ice crystals in a low-temperature environment, and the surface subjected to spraying treatment has relatively low surface energy and low adhesion, so that the surface has a good antifouling effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano structure functional surface preparation, and in particular, relates to a micro-array structure surface with low-temperature antifouling and directional icing and a preparation method thereof. Background Art

[0002] In cold water, a layer of ice that is closely connected to the surface will form on the surface of the equipment. The accumulation of ice will increase the burden on the equipment, change the surface morphology and affect the surface characteristics, which will affect the safety, reliability and work efficiency of the equipment operation. In recent years, the development of anti-icing surfaces includes: active anti-icing surfaces, which are designed with low ice adhesion or super-hydrophobic surfaces by constructing rough and low surface energy surfaces; passive anti-icing surfaces, which achieve anti-icing through mechanical, heating and chemical methods. However, active anti-icing technology cannot maintain good results as the temperature decreases and the number of de-icing cycles increases, while passive anti-icing technology requires the consumption of materials and energy. Therefore, the engineering field urgently needs a new anti-icing or de-icing method to solve this problem. Summary of the invention

[0003] The purpose of the present invention is to provide a micro-array structure surface with low-temperature anti-fouling and directional icing and a preparation method thereof, which is used to solve the technical problems of low durability and high energy consumption in existing micro-structure surface anti-icing or deicing methods.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0005] According to the first aspect of the present invention, a surface having a low-temperature antifouling and directional icing microarray structure is provided, wherein the surface having a low-temperature antifouling and directional icing microarray structure is a wavy structure surface, wherein the wavy structure surface is distributed with an imbricate arrangement structure, wherein the imbricate outer edge is annular, and an array of grooves is distributed on the imbricate arrangement structure, wherein the groove cross section is an asymmetric geometric shape. The surface having a low-temperature antifouling and directional icing microarray structure is sprayed with a hydrophobic photothermal coating, so that the entire surface of the groove array is covered with photothermal particles.

[0006] According to a specific embodiment of the present invention, the wavy structure changes periodically, the line connecting the highest point of the wave crest is defined as the ridge line, the line connecting the lowest point of the wave trough is defined as the valley line, the ridge line and the valley line are either parallel or intersecting, the intersection value is θ, θ ranges from 0° to 15°, and θ is defined as 0° when parallel. The distance from the crest to the trough of the wavy structure ranges from 280μm to 320μm, the contour lines of the crest and trough are minor arcs, the radius is close to the range of 200μm to 220μm, and the wave period length of the wavy structure is 790μm to 810μm.

[0007] According to a specific embodiment of the present invention, the wavy structure surface is distributed with an imbricate arrangement structure along the longitudinal direction, the imbricate arrangement structure is perpendicular to the wavy structure, the outer edge of the imbricate is annular, and its radius is 7mm to 10mm, the imbricate arrangement structure is perpendicular to the wavy structure, and the overall height of the imbricate arrangement structure gradually decreases along the longitudinal direction, that is, the center of the concave surface is higher than the outer edge of the outer curved surface, and the height difference between adjacent imbricate arrangement structures is 25μm to 45μm; the imbricate arrangement structures are parallel to each other and the span of the annular structure is 340μm to 360μm.

[0008] According to a specific embodiment of the present invention, the groove width is 3 μm to 7 μm, the depth is 4 μm to 6 μm, the spacing is 12 μm to 18 μm, and the groove cross-section is an asymmetric geometric shape of an inverted right-angled trapezoid or an inverted sawtooth.

[0009] According to a specific embodiment of the present invention, the photothermal particles covering the entire surface of the groove array are photothermal material silicon carbide particles, the particles are evenly distributed, and the particle diameter ranges from 0 to 2 μm.

[0010] According to a second aspect of the present invention, there is provided a method for preparing a surface having a low-temperature antifouling and directional icing microarray structure, comprising:

[0011] Step 1: Processing the aluminum alloy substrate to form a wavy structure;

[0012] The specific process of forming the wave-shaped structure is:

[0013] The drawing of the wavy structure is introduced into the electric spark cutting processing system, and the wavy structure is processed on the aluminum alloy substrate; either a one-time forming method or a material etching method is adopted.

[0014] Step 2: Fix the workpiece processed in step 1 (here the workpiece is the aluminum alloy substrate with a wavy structure processed on the surface) with a clamp on the fully automatic six-degree-of-freedom macro stage, import the shingle arrangement structure drawing into the laser electronic control equipment, start the laser marking machine, and the laser marking machine processes the shingle arrangement structure on the surface of the substrate according to the instructions of the imported drawing.

[0015] Step 3: Adjust the fully automatic six-degree-of-freedom macro stage to perform laser positioning. Process a groove array on the surface of the shingle-shaped arrangement structure;

[0016] Step 4: The surface of the workpiece processed by laser in step 2 is ultrasonically cleaned with deionized water for 10 minutes to remove surface impurities;

[0017] Step 5: Add 40 mg of silicon carbide powder with a diameter of 1 μm into 100 mL of ethanol and disperse it in a beaker by ultrasonication to form a suspension;

[0018] Step 6: Add 4 mL of tetraethoxysilane and 2 mL of an ethanol solution containing 1% heptadecafluorodecyltrimethoxysilane to the suspension obtained in step 5, and continue ultrasonic treatment for 30 min;

[0019] Step 7: Put the mixed liquid obtained after step 6 into the spray gun, and spray the mixed liquid evenly on the workpiece at a pressure of 3kg and a nozzle distance of 15cm;

[0020] Step 8: The workpiece sprayed in step 7 is naturally cured at room temperature, and the aluminum alloy substrate with a low-temperature antifouling and directional icing microarray structure surface is processed.

[0021] Through the above design scheme, the present invention can bring the following beneficial effects:

[0022] First, the present invention prepares a microarray structure surface with low-temperature antifouling and directional icing, which can allow ice nuclei to grow preferentially on the edge of the shingle-like arrangement structure;

[0023] Second, the present invention prepares a micro-array structure surface with low-temperature antifouling and directional ice formation. Due to the characteristics of directional ice formation, ice grows along the edge of the shingle-shaped arrangement structure, while there is almost no ice at the bottom of the groove, thereby reducing the contact area between the workpiece surface and ice and the low ice adhesion strength;

[0024] Third, the present invention prepares a surface with low-temperature antifouling and directional icing microarray structure, which has a photothermal effect and can remove ice under light;

[0025] Fourth, the present invention prepares a surface with low-temperature antifouling and directional icing microarray structure, which can be removed with a small external force;

[0026] Fifth, the present invention prepares a microarray structure surface with low-temperature antifouling and directional ice formation, which still has directional ice formation and low ice adhesion when underwater;

[0027] Sixth, the present invention prepares a microarray structure surface with low-temperature antifouling and directional icing, which removes ice by relying on the water flow speed when underwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present application. The exemplary embodiments of the present invention and their descriptions are used to understand the present invention and do not constitute improper limitations of the present invention. In the drawings:

[0029] Figure 1 Schematic diagram of the process of preparing a surface with low-temperature antifouling and directional icing microarray structure.

[0030] Figure 2 This is a schematic diagram of the structure after wire cutting in the method for preparing a microarray structure surface with low-temperature antifouling and directional icing.

[0031] Figure 3 Schematic diagram of the directional icing microarray structure surface designed for low-temperature anti-fouling and directional icing microarray structure surface.

[0032] Figure 4 It is a schematic front view of a directional icing microarray structure surface designed for low-temperature anti-fouling and directional icing microarray structure surface.

[0033] Figure 5 It is a cross-sectional schematic diagram of the shingle-like arrangement structure.

[0034] Figure 6 Schematic diagram of the cross section of an asymmetric groove array on a shingled arrangement structure.

[0035] Figure 7 Schematic diagram of photothermal particles on the grooves in the method for preparing a surface with a low-temperature anti-fouling and directional icing microarray structure.

[0036] Figure 8 This is a diagram showing the working principle of the surface of the microarray structure with low-temperature anti-fouling and directional icing.

[0037] In the figure: 1- shingle-like arrangement structure; 2- groove array. DETAILED DESCRIPTION

[0038] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical scheme of the present invention is clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the present invention is not limited to the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and actual conditions.

[0039] like Figures 1 to 7As shown, a microarray structure surface with low temperature antifouling and directional icing is provided. The microarray structure surface with low temperature antifouling and directional icing is a wavy structure surface. The line connecting the highest part of the wave crest is defined as the ridge line, and the line connecting the lowest part of the wave trough is defined as the valley line. The ridge line and the valley line are either parallel or intersecting. The intersection value is θ, and the value range of θ is 0° to 15°. When parallel, θ is defined as 0°. The distance from the wave crest to the wave trough of the wavy structure is in the range of 280μm to 320μm. The contour lines of the wave crest and the wave trough are minor arcs, and the radius is close to the value range of 200μm to 220μm. The wave period length of the wavy structure is 790μm to 810μm. The wavy structure surface is distributed with a shingle-like arrangement structure along the longitudinal direction. The shingle-like arrangement structure is perpendicular to the wavy structure. The outer edge of the shingle is annular with a radius of 7mm to 10mm. The overall height of the shingle-like arrangement structure gradually decreases along the longitudinal direction, that is, the center of the concave surface is higher than the outer edge of the outer curved surface. The height difference between adjacent shingle-like arrangement structures is 25μm to 45μm; the shingle-like arrangement structures are parallel to each other and the span of the annular structure is 340μm to 360μm. A groove array is distributed on the surface of the shingle-like arrangement structure, with a groove width of 3μm to 7μm, a depth of 4μm to 6μm, and a spacing of 12μm to 18μm. The cross-sectional shape of the groove is an inverted right-angle trapezoid, but it is not limited to this, and can also be an asymmetric geometric shape such as an inverted sawtooth. Silicon carbide particles of photothermal material are distributed on the surface of the groove, and the particles are evenly distributed, and the particle diameter ranges from 0 to 2μm. Such a numerical selection is beneficial to the segmentation of the airflow, and there is no ice in the groove when the surface is frozen.

[0040] The present invention provides a method for preparing a surface having a low-temperature antifouling and directional icing microarray structure, comprising the following steps, and the following steps are performed in sequence:

[0041] Step 1: Import the drawing of the wavy structure into the EDM machining system to machine the wavy structure on the aluminum alloy substrate;

[0042] Step 2: Fix the workpiece processed in step 1 on the fully automatic six-degree-of-freedom macro stage with a fixture; import the imbricate arrangement structure drawing into the laser electronic control device, start the laser marking machine, and the laser marking machine processes the imbricate arrangement structure on the surface of the substrate according to the instructions of the imported drawing;

[0043] Step 3: Adjust the fully automatic six-degree-of-freedom macro stage to perform laser positioning; process a groove array on the surface of the shingle-shaped arrangement structure;

[0044] Step 4: The surface of the workpiece processed by laser in step 2 is ultrasonically cleaned with deionized water for 10 minutes to remove surface impurities;

[0045] Step 5: Add 40 mg of silicon carbide powder with a diameter of 1 μm into 100 mL of ethanol and disperse it in a beaker by ultrasonication to form a suspension;

[0046] Step 6: Add 4 mL of tetraethoxysilane and 2 mL of an ethanol solution containing 1% heptadecafluorodecyltrimethoxysilane to the suspension obtained in step 5, and continue ultrasonic treatment for 30 min;

[0047] Step 7: Put the mixed liquid obtained after step 6 into the spray gun, and spray the mixed liquid evenly on the workpiece at a pressure of 3kg and a nozzle distance of 15cm;

[0048] Step 8: The workpiece sprayed in step 7 is naturally cured at room temperature, and the surface processing with low-temperature antifouling and directional icing microarray structure is completed.

[0049] In step 1, the preparation method of the wavy structure is not limited to electrospark machining, and can be obtained by a one-step forming method or a material etching method.

[0050] like Figure 8 As shown, the working process of the surface of the microarray structure with low-temperature antifouling and directional icing prepared by the present invention is as follows:

[0051] In a low-temperature environment, due to the presence of the shingle-like arrangement structure, water molecules are more likely to gather and nucleate at the edge of the step. When these tiny ice nuclei form ice strips, the airflow around the shingle-like arrangement structure begins to flow toward the ice nuclei, causing a larger pressure gradient locally, so that more water vapor flows to the ice on the edge of the shingle-like arrangement structure. At the same time, the asymmetric groove divides the airflow into smaller intervals, which makes it easier for the gas therein to be pushed to the edge of the shingle-like arrangement structure by the pressure difference at both ends of the groove. Therefore, compared with the asymmetric groove structure, the ice on the edge of the shingle-like arrangement structure grows faster. In addition, even underwater, since the vapor pressure of ice is lower than that of water, the condensed water in the asymmetric groove will be redirected to the groove and the edge of the shingle-like arrangement structure. This process will result in a relatively free ice in the asymmetric groove to achieve the function of directional ice formation. The workpiece prepared based on such characteristics can ensure that it is not covered by ice crystals in a low-temperature environment, and the surface after spraying has low surface energy and low adhesion, which makes the surface have a good anti-fouling effect. The photothermal particles not only facilitate the removal of ice, but also improve the contact state between the droplets and the surface, thereby affecting the surface wettability. The wavy structure strengthens the surface mechanical properties and increases its durability.

Claims

1. A microarray structure surface with low-temperature antifouling and directional icing, characterized in that: The surface of the microarray structure with low-temperature antifouling and directional icing is a wavy structure surface, and the wavy structure surface is distributed with a shingle-like arrangement structure, the outer edge of the shingle is annular, and a groove array is distributed on the shingle-like arrangement structure. The groove cross-section is an asymmetric geometric shape. The surface of the microarray structure with low-temperature antifouling and directional icing is sprayed with a hydrophobic photothermal coating, so that the entire surface of the groove array is covered with photothermal particles.

2. The low-temperature antifouling and directional icing microarray structure surface according to claim 1, characterized in that: The wave structure changes periodically. The line connecting the highest point of the wave crest is defined as the ridge line, and the line connecting the lowest point of the wave trough is defined as the valley line. The ridge line is parallel to the valley line, or the ridge line crosses the valley line. The intersection value is θ, and the value range of θ is 0° to 15°.

3. The low-temperature antifouling and directional icing microarray structure surface according to claim 1, characterized in that: The vertical distance from the crest to the trough of the wavy structure is 280μm to 320μm, the contour lines of the crest and trough are minor arcs with similar radii ranging from 200μm to 220μm, and the wave period length of the wavy structure is 790μm to 810μm.

4. The low-temperature antifouling and directional icing microarray structure surface according to claim 1, characterized in that: The wavy structure surface is distributed with an imbricate structure along the longitudinal direction. The outer edge of the imbricate structure is annular with a radius of 7 mm to 10 mm. The imbricate structure is perpendicular to the wavy structure. The overall height of the imbricate structure gradually decreases along the longitudinal direction, that is, the center of the concave surface is higher than the outer edge of the outer curved surface. The height difference between adjacent imbricate structures is 25 μm to 45 μm. The imbricate structures are parallel to each other and the span of the annular structure is 340 μm to 360 μm.

5. The low-temperature antifouling and directional icing microarray structure surface according to claim 1, characterized in that: The groove cross section is an inverted right-angle trapezoid, the groove width is 3μm to 7μm, the depth is 4μm to 6μm, and the spacing is 12μm to 18μm.

6. The low-temperature antifouling and directional icing microarray structure surface according to claim 1, characterized in that: The cross section of the groove is inverted sawtooth shape.

7. The low-temperature antifouling and directional icing microarray structure surface according to claim 1, characterized in that: The entire surface of the groove array is covered with photothermal particles, which are photothermal material silicon carbide particles. The particles are evenly distributed and the particle diameter ranges from 0 to 2 μm.

8. A method for preparing a surface having a low-temperature antifouling and directional icing microarray structure as claimed in any one of claims 1 to 7, characterized in that: The process includes the following steps, which are performed in sequence: Step 1: Processing the aluminum alloy substrate into a wave-shaped structure; Step 2: Fix the workpiece processed in step 1 on the fully automatic six-degree-of-freedom macro stage with a fixture, import the imbricate arrangement structure drawing into the laser electronic control device, start the laser marking machine, and the laser marking machine processes the imbricate arrangement structure on the surface of the substrate according to the instructions of the imported drawing; Step 3: Adjust the fully automatic six-degree-of-freedom macro stage, perform laser positioning, and process a groove array on the surface of the shingle-shaped arrangement structure; Step 4: The surface of the workpiece processed by laser in step 2 is ultrasonically cleaned with deionized water for 10 minutes to remove surface impurities; Step 5: Add 40 mg of silicon carbide powder with a diameter of 1 μm into 100 mL of ethanol and disperse it in a beaker by ultrasonication to form a suspension; Step 6: Add 4 mL of tetraethoxysilane and 2 mL of an ethanol solution containing 1% heptadecafluorodecyltrimethoxysilane to the suspension obtained in step 5, and continue ultrasonic treatment for 30 min; Step 7: Put the mixed liquid obtained after step 6 into the spray gun, and spray the mixed liquid evenly on the workpiece at a pressure of 3kg and a nozzle distance of 15cm; Step 8: The workpiece sprayed in step 7 is naturally cured at room temperature, and the surface processing with low-temperature antifouling and directional icing microarray structure is completed.

9. The method for preparing a surface having a low-temperature antifouling and directional icing microarray structure according to claim 8, characterized in that: The wavy structure formed by the aluminum alloy matrix is ​​formed by electric spark wire cutting, or by one-time molding with a mold, or by a material etching method.

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