A ridge structure grid-like super-hydrophobic surface for ice prevention and a method for preparing the same

Abstract

The present application relates to the technical field of anti-icing functional surface material, and particularly relates to a ridge structure grid-shaped super-hydrophobic surface for preventing ice and a preparation method thereof.A specific technical scheme is as follows: a ridge structure grid-shaped super-hydrophobic surface for preventing ice, comprising a substrate, the surface of the substrate is coated with a super-hydrophobic coating and is provided with protruding ridge structures, the ridge structures are arranged perpendicularly to each other on the upper surface of the substrate to form a grid shape, and the grid bottom surrounded by the ridge structures is a grid plane.The present application realizes the regulation of the dynamic behavior of the impacting liquid droplets by using the millimeter-level ridge structures which are perpendicular to each other, and this design can not only effectively shorten the contact time at any position on the surface, but also effectively inhibit the accumulation of liquid droplets on the surface at most positions, thereby fundamentally preventing and reducing the surface icing problem.

Description

Technical Field

[0001] This invention relates to the field of anti-icing functional surface materials technology, specifically to a ridge-structured mesh-like superhydrophobic surface for anti-icing and its preparation method. Background Technology

[0002] Surface icing is widespread in engineering facilities and natural environments in cold climates, causing numerous problems in many fields such as aerospace, power and communications, energy and power, and chemical engineering. Current anti-icing / de-icing technologies mainly include mechanical de-icing, thermal melting, and chemical anti-icing. However, these technologies suffer from high energy consumption, limited anti-icing time, and incomplete de-icing.

[0003] In recent years, using the bouncing properties of impacting droplets on superhydrophobic surfaces to suppress icing has become a research hotspot and is considered a promising new method for suppressing icing. Its core mechanism lies in using the rapid bouncing behavior of droplets after impact to shorten the solid-liquid contact time, allowing the droplets to detach from the surface before freezing, thus inhibiting ice nucleation from the source.

[0004] When a droplet impacts a superhydrophobic surface, there is a theoretical minimum contact time. Research has found that incorporating ridge structures on the superhydrophobic surface can overcome this theoretical limitation, reducing the solid-liquid contact time. Therefore, optimizing the design of the surface ridge structure to reduce the droplet-surface contact time is crucial for improving anti-icing performance.

[0005] Patent (CN106521465A) provides a three-level structured superhydrophobic surface for anti-icing. The superhydrophobic surface with multiple parallel ridges is prepared by a three-step method using machining, sandblasting and hydrothermal techniques. It achieves anti-icing by shortening the contact time. However, if an eccentric impact occurs, the contact time reduction effect will be significantly weakened. The contact time is significantly affected by the impact position. The three-step preparation process is complicated, costly and time-consuming.

[0006] Patent (CN116278198A) provides a mesh-like macro-micro composite surface, which is formed by multiple convex strips arranged in a cross pattern to form a mesh. The bottom of the mesh cavity formed by the convex strips is an inwardly recessed notch. This surface can effectively reduce the contact time at any position. However, under complex working conditions, droplets are prone to accumulate and freeze in the recessed area at the bottom of the mesh cavity. Furthermore, the bottom of the mesh cavity needs to be additionally processed into a curved surface, which increases the processing cost.

[0007] In summary, single-ridge structures or parallel array ridge structures have limitations in achieving a significant reduction in surface contact time. Furthermore, existing mesh-like superhydrophobic surfaces are prone to ice buildup in their recessed areas, and their fabrication costs and requirements are high. Therefore, designing an anti-icing surface that can comprehensively reduce droplet contact time, minimize impact droplet buildup, and is simple and inexpensive to prepare remains a critical problem that urgently needs to be solved. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a ridge-structured mesh-like superhydrophobic surface for anti-icing and its preparation method. The millimeter-scale ridge structure with mutually perpendicular intersections enables the control of the dynamic behavior of impacting droplets. This design can not only effectively shorten the contact time at any position on the surface, but also effectively suppress droplet accumulation on the surface at most positions, thereby fundamentally preventing and reducing the problem of surface icing.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] This invention discloses a ridge-structured mesh-like superhydrophobic surface for anti-icing, comprising a substrate, the surface of which is coated with a superhydrophobic coating and has protruding ridge structures. The ridge structures are arranged perpendicularly to each other on the upper surface of the substrate to form a mesh, and the bottom of the mesh formed by the ridge structures is a mesh plane.

[0011] Preferably, the cross-sectional shape of the ridge structure is one of a triangle, a semicircle, and an inverted semicircle, and the size is on the order of millimeters.

[0012] Preferably, the superhydrophobic coating is modified silica nanoparticles.

[0013] Preferably, based on the average diameter D of the impacting droplet, the ridge height H of a single ridge structure is (0.1~0.4)D, the ridge width W is 2H, and the grid plane width L is (0.8~1.5)D.

[0014] Accordingly, a method for preparing the ridge-structured mesh-like superhydrophobic surface for anti-icing includes the following steps:

[0015] (1) A ridge structure is formed on the substrate, and the surface is polished with sandpaper with a grit of 800 mesh and 1000 mesh, and then ultrasonically cleaned with deionized water.

[0016] (2) Spray the mixture of modified silica nanoparticles onto the surface of the substrate after step (1).

[0017] Preferably, the preparation process of the modified silica nanoparticles is as follows: SiO2 nanoparticles are ultrasonically dispersed in ethanol to form a uniform suspension; then 3-aminopropyltriethoxysilane is added and stirred for 0.5-1.5 h; then heptadecafluorodecyltrimethoxysilane is added and stirred for another 2-4 h.

[0018] Preferably, the mass-to-volume ratio of the SiO2 nanoparticles to 3-aminopropyltriethoxysilane is 2-5:1, and the mass-to-volume ratio of the SiO2 nanoparticles to heptadecafluorodecyltrimethoxysilane is 4-10:1.

[0019] Preferably, the ridge structure is processed on the substrate using 3D printing technology, CNC milling technology, or laser etching technology.

[0020] The present invention has the following beneficial effects:

[0021] 1. The anti-icing surface disclosed in this invention can effectively reduce contact time at any location, is suitable for various working conditions, and achieves anti-icing across the entire surface area.

[0022] 2. Compared with existing superhydrophobic surfaces, the ridge-structured mesh-like superhydrophobic surface not only reduces the solid-liquid contact time, but also further reduces and avoids the adhesion and accumulation of droplets on the surface in most locations, resulting in superior anti-icing performance.

[0023] 3. This invention prepares a superhydrophobic surface with a ridge structure using machining and spraying techniques. Compared with existing technologies, the ridge structure has millimeter-level dimensions, low precision requirements, no need for high-precision instruments and equipment, and the preparation method is simple and inexpensive. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the surface contact angle after spraying a superhydrophobic coating.

[0025] Figure 2 A schematic diagram of a ridge-structured, mesh-like superhydrophobic surface;

[0026] Figure 3 A schematic cross-sectional view of a ridge-structured mesh-like superhydrophobic surface;

[0027] Figure 4 For droplets at different Weber numbers We = 25.6 and 52.6 (… The graph shows a comparison of contact time at different impact positions when ρ is the droplet density, D0 is the initial diameter of the droplet, v0 is the impact velocity of the droplet, and σ is the surface tension of the droplet.

[0028] Figure 5 It is one type of ridge-structured mesh-like superhydrophobic surface;

[0029] Figure 6 It is another type of ridge-structured, mesh-like superhydrophobic surface;

[0030] In the figure, 1-substrate; 2-single ridge structure; 3-grid plane; 4-intersection of ridge structures. Detailed Implementation

[0031] 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 some embodiments of the present invention, and not all embodiments. 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.

[0032] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0033] The present invention discloses a ridge-structured mesh-like superhydrophobic surface for anti-icing, comprising a substrate 1, wherein the surface of the substrate 1 is coated with a superhydrophobic coating and has protruding ridge structures, the ridge structures are arranged perpendicularly to each other on the upper surface of the substrate to form a mesh, and the bottom of the mesh formed by the ridge structures is a mesh plane 3.

[0034] The cross-sectional shape of the ridge structure is one of a triangle, a semicircle, and an inverted semicircle, or a shape similar to a triangle, a semicircle, and an inverted semicircle, with a size on the order of millimeters.

[0035] The ridge-structured mesh-like superhydrophobic surface disclosed in this invention is as follows: Figure 5-6 As shown, where, Figure 5 The ridge structure has a semi-circular cross-sectional shape, and the bottom of the enclosed grid is a grid plane; Figure 6 The ridge structure has a sharp profile (similar to a triangle) in cross-section, and the bottom of the grid it forms is also a grid plane.

[0036] Millimeter-scale ridge structures alter the spreading and retraction process of impacting droplets: impacting droplets preferentially spread and retract along the ridge direction, while spreading and retraction perpendicular to the ridge direction are restricted, resulting in an asymmetry in spreading and retraction. Under the combined action of retraction force and inertial force, the retraction of the liquid film on the ridge is accelerated, leading to droplet splitting, reducing the retraction distance and time, and thus reducing the contact time between the impacting droplet and the surface.

[0037] Impact at a grid plane can also shorten contact time: when a droplet impacts a grid plane, the spreading and retraction process is restricted by the surrounding ridge structure, and the spreading and retraction process of the droplet cannot be fully carried out, which reduces the contact time.

[0038] Furthermore, based on the average diameter D of the impacting droplets under different working conditions, the ridge height H of a single ridge structure 2 is (0.1~0.4)D, the ridge width W is 2H, and the grid plane width L is (0.8~1.5)D.

[0039] Furthermore, the superhydrophobic coating is modified silica nanoparticles. The preparation process of the modified silica nanoparticles is as follows: SiO2 nanoparticles are ultrasonically dispersed in ethanol to form a uniform suspension; then 3-aminopropyltriethoxysilane is added and stirred for 0.5-1.5 h; then heptadecafluorodecyltrimethoxysilane (FAS-17) is added and stirring is continued for 2-4 h.

[0040] The mass-to-volume ratio of SiO2 nanoparticles to 3-aminopropyltriethoxysilane is 2-5:1, and the mass-to-volume ratio of SiO2 nanoparticles to FAS-17 is 4-10:1.

[0041] Compared to the super-sparse horizontal plane, when the impact location is a grid plane, even with the weakest effect on reducing contact time, it can still shorten the contact time by at least 18%. When the impact location is the intersection of the ridge structure, the effect on reducing contact time is the most significant, and can reduce the contact time by up to 50%.

[0042] At impact locations other than the grid plane, the impacting droplets bounce on the ridge surface and deflect or even break apart, moving away from the initial impact location and reducing the accumulation of impacting droplets.

[0043] This invention also discloses a method for preparing a ridge-structured mesh-like superhydrophobic surface for anti-icing, comprising the following steps:

[0044] (1) A ridge structure is formed on the substrate, and the surface is polished successively with sandpaper of 800 grit and 1000 grit to remove the oxide layer and make the surface smooth. The polished surface is then ultrasonically cleaned with deionized water for 10 minutes to remove surface impurities. The substrate can be an aluminum alloy substrate, model 6061. The ridge structure is processed on the substrate using 3D printing technology, CNC milling technology, or laser etching technology.

[0045] (2) Spray the mixture of modified silica nanoparticles onto the substrate surface treated in step (1) to ensure uniform coating coverage. Then, allow it to air dry at room temperature for 30 minutes to complete the preparation of the ridge-structured mesh-like superhydrophobic surface for anti-icing.

[0046] The present invention will be further described below with reference to specific embodiments.

[0047] Example 1

[0048] A method for preparing a ridge-structured mesh-like superhydrophobic surface for anti-icing includes the following steps:

[0049] (1) Process the aluminum alloy substrate to form a triangular ridge structure.

[0050] The specific process of forming a triangular ridge structure is as follows:

[0051] The ridge structure can be fabricated on the surface of an aluminum alloy substrate using 3D printing technology according to the design requirements, or using CNC milling technology, or using laser etching technology.

[0052] like Figure 2-3 As shown, under different working conditions, the average diameter of the impacting droplet is D = 2.5 mm, the ridge height of a single ridge structure is H = 0.5 mm, the ridge width is W = 1.0 mm, the grid plane width is L = 2.5 mm, and the grid plane width is equal to the average diameter of the droplet.

[0053] (2) The surface processed in step (1) is pretreated by grinding and cleaning;

[0054] The surface grinding and cleaning pretreatment refers to grinding the surface with sandpaper of 800 and 1000 grits to remove the oxide layer and make the surface smooth. The ground surface is then ultrasonically cleaned with deionized water for 10 minutes to remove surface impurities.

[0055] (3) Disperse 3.6g of SiO2 nanoparticles in 40mL of ethanol by ultrasonication for 20min to form a uniform suspension; add 1mL of 3-aminopropyltriethoxysilane to the suspension and stir with a magnetic stirrer for 1h; then add 500μL of FAS-17 and continue to stir with a magnetic stirrer for 3h to obtain a modified silica nanoparticle mixture.

[0056] (4) Transfer the mixture obtained in step (3) to a spray gun and spray the mixture evenly onto the surface treated in step (2) to ensure uniform coating coverage; then let it dry naturally at room temperature for 30 minutes. The ridge structure mesh superhydrophobic surface for anti-icing is now ready.

[0057] The contact angle of the prepared surface is measured, such as... Figure 1 As shown, the droplet contact angle on the surface is greater than or equal to 150°, and the surface exhibits superhydrophobic properties.

[0058] Figure 4 The graph shows a comparison of contact times at different droplet impact locations. As can be seen, at lower We numbers (We = 25.6), compared to a superhydrophobic horizontal surface (contact time 12 ms), droplet impact on a ridge-structured mesh-like superhydrophobic surface can reduce the contact time by 18-50%, especially at impact location 3 on mesh plane. Figure 2The contact time is 9.8 ms, reducing the contact time by 18%, showing the weakest reduction effect. At impact location 4, the contact time is 6.2 ms, reducing the contact time by 50%, showing the most significant reduction effect. At higher We numbers (We = 52.6), droplet impact on the ridge-structured mesh-like superhydrophobic surface can reduce the contact time by 42-50%, with the smallest reduction effect at impact location 3 (mesh plane), resulting in a contact time of 6.9 ms. The most significant reduction effect is at impact location 4 (ridge intersection), with a contact time of 6.0 ms. Furthermore, the contact time is also 6.0 ms at impact location 2 (a single ridge). Therefore, the ridge-structured mesh-like superhydrophobic surface can reduce contact time at any location.

[0059] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A ridge-structured mesh-like superhydrophobic surface for anti-icing, comprising a substrate, characterized in that: The substrate surface is coated with a superhydrophobic coating and has protruding ridge structures. The ridge structures are arranged perpendicularly to each other on the upper surface of the substrate to form a grid, and the bottom of the grid formed by the ridge structures is a grid plane. The cross-sectional shape of the ridge structure is one of triangle, semicircle, and inverted semicircle, and the size is on the order of millimeters; based on the average diameter D of the impacting droplet, the ridge height H of a single ridge structure is (0.1~0.4)D, the ridge width W is 2H, and the grid plane width L is (0.8~1.5)D; The superhydrophobic coating is modified silica nanoparticles. The preparation process of the modified silica nanoparticles is as follows: SiO2 nanoparticles are ultrasonically dispersed in ethanol to form a uniform suspension; then 3-aminopropyltriethoxysilane is added and stirred for 0.5-1.5 h; then heptadecafluorodecyltrimethoxysilane is added and stirred for another 2-4 h; the mass-to-volume ratio of SiO2 nanoparticles to 3-aminopropyltriethoxysilane is 2-5:1, and the mass-to-volume ratio of SiO2 nanoparticles to heptadecafluorodecyltrimethoxysilane is 4-10:

1.

2. A method for preparing the ridge-structured mesh-like superhydrophobic surface for anti-icing as described in claim 1, characterized in that: Includes the following steps: (1) A ridge structure is formed on the substrate, and the surface is polished with sandpaper with a grit of 800 mesh and 1000 mesh, and then ultrasonically cleaned with deionized water. (2) Spray the mixture of modified silica nanoparticles onto the surface of the substrate after step (1) treatment; The preparation process of the modified silica nanoparticles is as follows: SiO2 nanoparticles are ultrasonically dispersed in ethanol to form a uniform suspension; then 3-aminopropyltriethoxysilane is added and stirred for 0.5-1.5 h; then heptadecafluorodecyltrimethoxysilane is added and stirred for another 2-4 h; the mass-volume ratio of SiO2 nanoparticles to 3-aminopropyltriethoxysilane is 2-5:1, and the mass-volume ratio of SiO2 nanoparticles to heptadecafluorodecyltrimethoxysilane is 4-10:

1.

3. The preparation method according to claim 2, characterized in that: The ridge structure is fabricated on the substrate using 3D printing technology, CNC milling technology, or laser etching technology.

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