A superhydrophobic anti-icing surface based on a super-elliptical topological structure and a preparation method thereof

Abstract

The present invention discloses a superhydrophobic anti-icing surface based on a super-elliptical topological structure and a preparation method thereof. The superhydrophobic anti-icing surface includes a super-elliptical topological structure substrate and a superhydrophobic coating; the micro-structure of the super-elliptical topological structure substrate has a protection function, protecting the internal superhydrophobic coating from being damaged by impact or worn by friction and becoming ineffective; the superhydrophobic coating has a nanostructure with intrinsic superhydrophobicity, which can reduce the solid-liquid contact area and weaken the solid-liquid heat transfer, thereby delaying icing and reducing ice adhesion, and having anti-icing performance. The superhydrophobic anti-icing surface of the present invention has long-lasting and mechanically robust superhydrophobicity. By using the super-elliptical topological micro-structure to protect the superhydrophobic nanostructure, the problems of poor mechanical robustness and non-abrasion resistance of the superhydrophobic surface are solved, and the long-lasting property and durability of the superhydrophobic surface are enhanced, and it can be applied to fields such as aerospace, energy, and transportation.

Description

Technical Field

[0001] The present invention belongs to the field of superhydrophobic anti-icing, and relates to a superhydrophobic anti-icing surface based on a super-elliptical topological structure and a preparation method thereof. Background Art

[0002] In a low-temperature environment, the surface is prone to icing, which brings potential safety hazards and energy efficiency losses to fields such as aerospace, energy, and transportation. Traditional anti-icing methods have poor environmental friendliness and high energy consumption. Therefore, a method for preparing a green and low-energy-consumption anti-icing surface is needed to reduce ice formation and improve the anti-icing performance of the surface.

[0003] Learning from nature, biological surfaces such as lotus leaves, rice leaves, and butterfly wings have superhydrophobic phenomena. Their unique solid-gas-liquid contact interfaces guide the construction of new anti-icing surfaces. Bionic superhydrophobic surface anti-icing inspired by nature is a passive anti-icing technology. It mainly reduces the contact area and contact time of droplets hitting the solid surface by using interface materials to lower the surface energy or constructing micro-nano composite structures on the anti-icing area surface to inhibit surface icing, thereby greatly reducing the energy consumption required for anti-icing and having great engineering application prospects.

[0004] However, a large number of research results show that the low solid-liquid contact area of the superhydrophobic surface causes high local stress, resulting in poor mechanical stability and being easily damaged by natural climate (sunshine, sand and dust, wind and rain), external forces (impact, friction), icing-deicing cycles, etc. Eventually, the superhydrophobic surface fails and the anti-icing efficiency decreases, making mechanical stability a key bottleneck restricting the application of superhydrophobic surfaces in the field of anti-icing. Therefore, it is necessary to protect the mechanically fragile nano-hydrophobic structure by using a super-elliptical topological microstructure to improve the mechanical stability of the superhydrophobic surface and expand its anti-icing application in fields such as aerospace, energy, and transportation. Summary of the Invention

[0005] Aiming at the problems of poor mechanical strength and durability of the existing superhydrophobic anti-icing surface, the present invention prepares a superhydrophobic anti-icing surface based on a super-elliptical topological structure by adopting a strategy of protecting the nanostructure of the superhydrophobic coating with a substrate super-elliptical topological microstructure, regulating the composition and ratio of the organic-inorganic hybrid superhydrophobic coating, and filling it into the microstructure based on the super-ellipse. The present invention discloses the types, compositions, and component ratios of a series of organic-inorganic hybrid superhydrophobic coatings, and details different methods of filling the superhydrophobic coating into the super-elliptical microstructure.

[0006] The preparation technical solution of the present invention is as follows:

[0007] A superhydrophobic anti-icing surface based on a super-elliptical topological structure, the superhydrophobic anti-icing surface comprising a super-elliptical topological structure substrate (1) and a superhydrophobic coating (2), wherein the microstructure of the super-elliptical topological structure substrate (1) has a protection function to protect the internal superhydrophobic coating (2) from being damaged by impact or worn by friction and becoming ineffective; the superhydrophobic coating (2) has a nanostructure with superhydrophobicity, which can reduce the solid-liquid contact area and weaken the solid-liquid heat transfer, thereby delaying icing and reducing ice adhesion, and has anti-icing performance.

[0008] The superhydrophobic anti-icing surface meets the following performance requirements: the water contact angle is greater than 150°, and the rolling angle is less than 10°; after undergoing multiple friction and wear, its surface still has superhydrophobicity; compared with the original substrate surface, it can extend the icing time and reduce the ice adhesion force; after undergoing multiple friction and wear, its surface still has anti-icing property.

[0009] The material of the super-elliptical topological structure substrate (1) is one of plastic, ceramic, metal, and composite material, and the topological structure unit is one of the super-elliptical shapes, which is obtained by laser processing. The shape curve of the super-ellipse is where the semi-diameters a and b of the super-ellipse have a value range of 60 - 500 μm, the exponential parameter n has a value range of 2 - 10. The value range of the distance between adjacent super-ellipses is 0 - 100 μm. The superhydrophobic coating (2) is an organic-inorganic hybrid material, the organic part is one of resin polymers, and the inorganic part is one of nanoparticles, and the two are blended by an organic solvent.

[0010] The super-elliptical topological structure substrate (1) and the superhydrophobic coating (2) are obtained by dip coating, knife coating, or spraying, and then heat-cured and formed.

[0011] The preparation method of the superhydrophobic anti-icing surface as described above in any one of the preceding claims comprises the following steps:

[0012] Step 1, the processing of the super-elliptical topological structure substrate (1) is to laser-process the substrate into a super-elliptical shape according to the design requirements;

[0013] Step 2, the preparation of the superhydrophobic coating (2) is to blend an organic resin and inorganic nanoparticles in an organic solvent and stir evenly;

[0014] Step 3, apply the superhydrophobic coating (2) into the microstructure of the super-elliptical topological structure substrate (1) by dip coating, knife coating, or spraying, and then perform heat curing;

[0015] Step 4, conduct a contact angle test on the prepared super-elliptical topological structure superhydrophobic anti-icing surface to evaluate its wettability. If the superhydrophobic requirements are not met, iterate the organic-inorganic hybrid ratio of the superhydrophobic coating (2) in Step 2 to increase the mass ratio of the nanoparticles.

[0016] Step 5, perform anti-icing performance testing on the prepared super-elliptical topological superhydrophobic anti-icing surface, that is, when the surface temperature is -20 °C, compare the ice nucleation delay time of 10 μl of supercooled droplets on it with that of the original bare substrate.

[0017] Step 6, perform friction testing on the prepared super-elliptical topological superhydrophobic anti-icing surface. After repeatedly rubbing the surface 50 times with sandpaper loaded with a 500 g weight, measure the surface contact angle to see if it still meets the superhydrophobic requirements; measure the surface ice nucleation delay time and compare it with that of the original bare substrate.

[0018] The beneficial effect of the superhydrophobic anti-icing surface based on the super-elliptical topological structure of the present invention is that it has long-lasting and mechanically robust superhydrophobicity and anti-icing performance. By using the super-elliptical topological micro-structure to protect the superhydrophobic nano-structure, the problems of poor mechanical robustness and non-wear resistance of the superhydrophobic surface are solved, and the long-lastingness and durability of the superhydrophobic surface are enhanced. Specifically, it still has the superhydrophobicity and anti-icing performance of the original surface after multiple rubbings, and can be applied to fields such as aerospace, energy, and transportation. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a superhydrophobic anti-icing surface based on the super-elliptical topological structure in Examples 1, 2, and 3;

[0020] Figure 2 is a surface topography diagram of a superhydrophobic anti-icing surface based on the super-elliptical topological structure in Example 1;

[0021] Figure 3 is an infiltration characterization diagram of a superhydrophobic anti-icing surface based on the super-elliptical topological structure in Example 1 after multiple rubbings.

[0022] Wherein: 1 - super-elliptical topological structure substrate; 2 - superhydrophobic coating. Detailed Embodiments

[0023] The present invention will be further described below with reference to the drawings and specific embodiments.

[0024] Example 1

[0025] A superhydrophobic anti-icing surface based on the super-elliptical topological structure, as Figure 1 shown, its structure includes: (1) a super-elliptical topological structure substrate 1, with a length and width of 30 mm × 30 mm and a material of organic glass acrylic, and its performance parameters are a density of 1.19 g / cm 3, with a Young's modulus of 3.6 GPa, a tensile strength of 60 MPa, a flexural strength of 110 MPa, a melting point of 130 °C, and a Poisson's ratio of 0.4; (2) Superhydrophobic coating 2, the organic part is the silicone polymer polydimethylsiloxane and a curing agent (Dow Corning, USA, Sylard 184), the inorganic part is silica nanoparticles (Degussa, R202), hydrophobic type, with an average particle size of 14 nm. Figure 1 Only the pattern design of four adjacent super-elliptical structures in the up, down, left, and right directions is schematically shown. In actual processing, according to the substrate size and the size of the super-elliptical structure, the topological pattern can be repeated. Superhydrophobic coating 2 is filled in the super-elliptical topological structure of the substrate. The surface morphology diagram of the actually prepared super-elliptical topological structure superhydrophobic and anti-icing surface is taken by an electron scanning microscope, and its structure is as Figure 2 shown.

[0026] Its preparation method is as follows:

[0027] Step 1, process a super-elliptical shape on an acrylic substrate of plexiglass by laser. Among them, the semi-diameters a and b of the super-ellipse are taken as 250 μm, the exponent n is taken as 3, and the adjacent spacing d is taken as 25 μm;

[0028] Step 2, blend polydimethylsiloxane, a curing agent, and silica nanoparticles in a n-hexane solvent according to a mass ratio of 7:0.7:3, and stir evenly;

[0029] Step 3, apply the superhydrophobic coating by scraping into the microstructure of the super-elliptical topological structure substrate, and then place it in a vacuum chamber for 10 minutes. Repeat this 2 - 3 times until the superhydrophobic coating fills the super-elliptical topological microstructure, and then cure it at 80 °C for 2 hours;

[0030] Step 4, conduct a contact angle test on the prepared super-elliptical topological structure superhydrophobic surface. The water contact angle is 155°, and the rolling angle is 5°, meeting the superhydrophobic requirements.

[0031] Step 5, conduct an anti-icing performance test on the prepared super-elliptical topological structure superhydrophobic and anti-icing surface. That is, when the surface temperature is -20 °C, the icing time of 10 μl of supercooled liquid droplets on it is delayed by more than 20 times compared to the original bare acrylic surface.

[0032] Step 6, repeatedly rub the super-elliptical superhydrophobic surface with sandpaper loaded with a 500 g weight. The single friction distance is 2 cm. After rubbing 50 times, the water contact angle of the super-elliptical topological structure superhydrophobic surface is 151°, and the rolling angle is 8°. As Figure 3 shown, it still meets the superhydrophobic requirements. And the icing time is delayed by more than 15 times compared to the original bare acrylic surface.

[0033] Example 2

[0034] A superhydrophobic anti-icing surface based on a super-elliptical topological structure, as Figure 1 shown, its structure includes: (1) A super-elliptical topological structure substrate with a length and width of 30 mm × 30 mm and a material of plexiglass acrylic. Its performance parameters are a density of 1.19 g / cm 3 , a Young's modulus of 3.6 GPa, a tensile strength of 60 MPa, a flexural strength of 110 MPa, a melting point of 130 °C, and a Poisson's ratio of 0.4; (2) A superhydrophobic coating, with the organic part being the silicone polymer polydimethylsiloxane (Dow Corning, Sylard 184, USA), and the inorganic part being silicon dioxide nanoparticles (Degussa, R202), which is hydrophobic with an average particle size of 14 nm.

[0035] Its preparation method is as follows:

[0036] Step 1, a super-elliptical shape is processed on the plexiglass acrylic substrate by laser. Among them, the semi-diameters a and b of the super-ellipse are taken as 250 μm, the exponent n is taken as 3, and the adjacent spacing d is taken as 75 μm;

[0037] Step 2, the silicone polymer polydimethylsiloxane and silicon dioxide nanoparticles are blended in a mass ratio of 7:0.7:3 in a n-hexane solvent and stirred evenly;

[0038] Step 3, the superhydrophobic coating is sprayed into the microstructures of the super-elliptical topological structure substrate at a pressure of 0.1 MPa. The distance between the substrate and the nozzle during spraying is 20 cm, and it is sprayed 2 times, and then cured at 80 °C for 2 hours;

[0039] Step 4, the contact angle of the prepared super-elliptical topological structure superhydrophobic surface is tested. The water contact angle is 145°, which does not meet the superhydrophobic requirement. Iterate the organic-inorganic hybridization ratio of the superhydrophobic coating 2 in Step 2, increase the mass ratio of the nanoparticles to 7:0.7:3.5, and then conduct the contact angle test again. The water contact angle is 153° and the rolling angle is 5°, meeting the superhydrophobic requirement;

[0040] Step 5, the anti-icing performance of the prepared super-elliptical topological structure superhydrophobic anti-icing surface is tested. That is, when the surface temperature is -20 °C, the icing time of 10 μl of supercooled droplets on it is delayed by more than 16 times compared with the original bare acrylic surface;

[0041] Step 6, use sandpaper loaded with a 500 g weight to repeatedly rub the super-elliptical superhydrophobic surface. The single friction distance is 2 cm. After rubbing 50 times, the water contact angle of the super-elliptical topological structure superhydrophobic surface is 150° and the rolling angle is 10°, still meeting the superhydrophobic requirement; the icing time is delayed by more than 10 times compared with the original bare acrylic surface.

[0042] Example 3

[0043] A superhydrophobic anti-icing surface based on a super-elliptical topological structure, as Figure 1 shown. Its structure includes: (1) A super-elliptical topological structure substrate with a length and width of 300 mm × 300 mm and a material of metal aluminum alloy. Its performance parameters are: density 2.81 g / cm 3 , Young's modulus 71.7 GPa, tensile strength 572 MPa, flexural strength 385 MPa, and Poisson's ratio 0.33; (2) A superhydrophobic coating. The organic part is epoxy resin E-51 and curing agent T-31 (Hangzhou Wuhuigang Adhesive Co., Ltd.), and the inorganic part is carbon nanoparticles with an average particle size of 20 nm.

[0044] Its preparation method is as follows:

[0045] Step 1: Use a laser to machine a super-elliptical shape on an aluminum alloy substrate. Among them, the semi-diameters a and b of the super-ellipse are taken as 250 μm, the exponent n is taken as 8, and the adjacent spacing d is taken as 25 μm;

[0046] Step 2: Blend epoxy resin E-51, curing agent T-31, and carbon nanoparticles in an acetone solvent according to a ratio of 7:3.5:3 and stir evenly;

[0047] Step 3: Spray the superhydrophobic coating into the microstructures of the super-elliptical topological structure substrate. The pressure is 0.1 MPa, the distance between the substrate and the nozzle during spraying is 20 cm, spray 2 times, and then cure at 60 °C for 2 hours;

[0048] Step 4: Conduct a contact angle test on the prepared super-elliptical topological structure superhydrophobic surface. The water contact angle is 156°, and the rolling angle is 2°, meeting the superhydrophobic requirements.

[0049] Step 5: Conduct an anti-icing performance test on the prepared super-elliptical topological structure superhydrophobic anti-icing surface. That is, when the surface temperature is -20 °C, the icing time of 10 μl of supercooled liquid droplets on it is delayed by more than 22 times compared with the original bare acrylic surface.

[0050] Step 6: Repeatedly rub the super-elliptical superhydrophobic surface with sandpaper loaded with a 500 g weight. The single friction distance is 2 cm. After 50 frictions, the water contact angle of the super-elliptical topological structure superhydrophobic surface is 152°, and the rolling angle is 7°, still meeting the superhydrophobic requirements; the icing time is delayed by more than 15 times compared with the original bare acrylic surface.

[0051] It should be noted that, according to the above embodiments of the present invention, those skilled in the art can fully implement the entire scope of the independent claims and dependent claims of the present invention, and the implementation process and method are the same as those of the above embodiments; moreover, the parts not elaborated in detail in the present invention belong to the well-known technology in the art. The above are only some specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those familiar with the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A superhydrophobic anti-icing surface based on a superellipse topological structure, characterized in that, The superhydrophobic anti-icing surface includes a super-elliptical topological structure substrate (1) and a superhydrophobic coating (2). The microstructure of the super-elliptical topological structure substrate (1) has a protective function to protect the internal superhydrophobic coating (2) from failure due to impact damage or frictional wear. The superhydrophobic coating (2) has a nanostructure with intrinsic superhydrophobicity, which can reduce the solid-liquid contact area and weaken the solid-liquid heat transfer, thereby delaying ice formation and reducing ice adhesion, and has anti-icing performance. The shape curve of the super-ellipse is , where the semi-diameters a and b of the super-ellipse range from 60 to 500 μm, and the exponential parameter n ranges from 3 to 10. The range of the spacing between adjacent super-ellipses is 0 to 75 μm. The superhydrophobic anti-icing surface meets the following superhydrophobic performance requirements: the water contact angle is greater than 150°, and the rolling angle is less than 10°. The material of the super-elliptical topological structure substrate (1) is one of plastic, ceramic, metal, and composite materials, and the topological structure unit is one of the super-elliptical shapes, which is obtained by laser processing. The superhydrophobic coating (2) is an organic-inorganic hybrid material. The organic part is one of resin polymers, and the inorganic part is one of nano-particles, and the two are obtained by blending with an organic solvent. The resin polymer is polydimethylsiloxane or epoxy resin. The nano-particle is nano-silica or carbon nano-particle. The particle size of the nano-particle is 1 to 30 nm.

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