Bionic rigid-elastic coupling microstructure anti-drag coating and preparation method thereof

Abstract

The invention relates to the technical field of surface bionic micro-nano structures, in particular to a bionic rigid-elastic coupling microstructure anti-drag coating and a preparation method thereof. According to the preparation method of the bionic rigid-elastic coupling microstructure anti-drag coating, the hydrophobic property of polydimethylsiloxane (PDMS) and the inherent magnetic property of Fe3O4 or CIP are utilized, the bionic coating with the rigid-elastic coupling microstructure is prepared on a stainless steel substrate through a magnetic field induction method, and the bionic coating has good underwater self-adaptive anti-drag performance. When the surface of the coating is in a water flow environment, the surface is subjected to a certain water pressure, and the rigid-elastic coupling microstructure is subjected to self-adaptive deformation. Wherein elastic deformation can absorb a part of energy, the turbine effect of the microstructure can decompose a large turbine into small turbines, and the small turbines and the dynamic rigid-elastic coupling microstructure jointly act to cope with water flow changes and reduce resistance. And after the surface water pressure is reduced, the microstructure recovers to the original height, and meanwhile, a relatively low solid-liquid contact area is kept.

Description

Technical Field

[0001] This invention relates to the field of surface biomimetic micro / nano structure technology, specifically to a biomimetic rigid-elastic coupling microstructure drag-reducing coating and its preparation method. Background Technology

[0002] With the development of cross-medium navigation and underwater engineering in recent years, the propulsion efficiency of underwater vehicles and related equipment has become an important research hotspot. Currently, when underwater equipment operates in a fluid environment, approximately 60% of its propulsion power is consumed in overcoming surface frictional resistance, resulting in significant energy loss, which directly affects the equipment's energy efficiency and operational safety. Preparing a biomimetic rigid-elastic coupled microstructure coating on the substrate surface is a relatively simple method to reduce surface frictional resistance and save energy.

[0003] Currently common biomimetic surface drag reduction technologies, such as lotus leaf-inspired superhydrophobic surfaces and pitcher plant-inspired superslippery surfaces, can reduce frictional resistance to some extent. However, in dynamic fluid environments, these technologies often suffer from problems such as easily damaged air or oil films, insufficient surface adaptability, or coating peeling, resulting in short-lived drag reduction effects that cannot meet the requirements of high efficiency and long-term operation. Many natural organisms, such as pufferfish, have an outer layer of elastic dermis and dispersed rigid spines encasing it. These dispersed rigid spines can adjust their tilt angle and height according to water flow velocity and pressure. The elastic dermis and dispersed rigid spines form a rigid-elastic coupled microstructure with high adaptability and self-regulation capabilities, allowing it to adjust its shape in real time according to fluid conditions, significantly reducing water flow resistance.

[0004] Based on the above ideas, we propose a method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating, which has achieved adaptive drag reduction capability of the prepared coating. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a biomimetic rigid-elastic coupling microstructure drag-reducing coating and its preparation method. The prepared coating combines the advantages of rigid and elastic materials, and can maintain structural stability while having a certain elastic adjustment capability, so as to adapt to the ever-changing fluid environment.

[0006] The technical solution adopted is as follows: A method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating includes the following steps: (1) Polish the stainless steel substrate until smooth, ultrasonically clean it, and then dry it for later use. (2) Mix the base components and curing agent of polydimethylsiloxane (PDMS) evenly, add magnetic particles to the mixture, stir evenly, place in a vacuum drying oven to remove air bubbles, and obtain the elastic precursor solution. (3) After uniformly coating the elastic precursor solution containing magnetic particles onto the surface of the treated stainless steel substrate, magnetic field induction and ultraviolet light irradiation are applied simultaneously; under the action of magnetic field, the magnetic particles are oriented and arranged, and the elastic precursor is cured by ultraviolet light irradiation, and finally a drag-reducing coating with rigid-elastic coupling microstructure is formed on the surface of stainless steel substrate.

[0007] PDMS is most commonly supplied in the form of a two-component kit (component A and component B). The base component, component A, is mainly the prepolymer base material, while component B is the curing agent. The two need to be mixed before use. The peroxide in component B decomposes to generate free radicals, which react with the silicon groups in the prepolymer of component A to form Si-O-Si bonds, thereby connecting the linear PDMS chains into a three-dimensional network structure, realizing the curing from liquid to elastomer.

[0008] Preferably, when pre-treating the stainless steel substrate, it is polished sequentially with 240#, 400#, 800#, 1000# and 1500# wet sandpaper, and then ultrasonically cleaned in anhydrous ethanol for 10 to 20 minutes.

[0009] Preferably, the base component of polydimethylsiloxane (PDMS) and the curing agent are mixed in a weight ratio of 7 to 20:1, and the magnetic particles account for 5% to 20% of the mass of the mixture.

[0010] Preferably, the magnetic particles are magnetic Fe3O4 or CIP (carbonyl iron powder) particles.

[0011] Preferably, a vacuum is drawn in a vacuum drying oven at room temperature for 10–20 minutes to remove air bubbles.

[0012] Preferably, in step (3), the coated stainless steel substrate is placed stably on the magnet to ensure that the contact surface between the substrate and the magnet is intact and free of foreign matter, and a magnetic field is applied to induce it. The synergistic effect of the two lasts for 1.5 to 2.5 hours to promote the formation of microstructures.

[0013] Preferably, in step (3), the magnetic field strength of the permanent magnet used is 1.45 T to 1.5 T, and the wavelength of the ultraviolet lamp is 365 nm.

[0014] A biomimetic rigid-elastic coupling microstructure drag-reducing coating is prepared using any of the methods described above.

[0015] The biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared by this invention can be applied to the preparation of hydrophobic and / or drag-reducing materials or material coatings.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The preparation method of the biomimetic rigid-elastic coupling microstructure drag-reducing coating provided by the present invention utilizes the hydrophobicity of polydimethylsiloxane (PDMS) and the inherent magnetic properties of Fe3O4 or CIP (carbonyl iron powder) to prepare a biomimetic coating with rigid-elastic coupling microstructure on a stainless steel substrate by magnetic field induction, which has good underwater adaptive drag reduction performance.

[0017] (2) The biomimetic rigid-elastic coupled microstructure drag-reducing coating prepared by the method of the present invention exhibits adaptive deformation when its surface is subjected to a certain water pressure in a water flow environment. The elastic deformation absorbs some energy, and the turbine effect of the microstructure decomposes the large turbine into smaller turbines. This dynamic rigid-elastic coupled microstructure works together to cope with changes in water flow and reduce drag. After the surface water pressure decreases, the microstructure returns to its original height while maintaining a low solid-liquid contact area, demonstrating its adaptive characteristics.

[0018] (3) The preparation method of the biomimetic rigid-elastic coupling microstructure drag-reducing coating in this invention is simple, easy to implement, low in cost, and has a high success rate. It has no special requirements on the shape of the substrate sample and has good industrial application prospects. Attached Figure Description

[0019] Figure 1 This is a 650x SEM image of the biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared in Example 1 of this invention.

[0020] Figure 2 This is a 3500x SEM image of the biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared in Example 1 of this invention.

[0021] Figure 3 This is a contact angle diagram on the biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared in Example 1 of the present invention.

[0022] Figure 4 These are tensile curves of samples of the biomimetic rigid-elastic coupled microstructure drag-reducing coatings prepared in Examples 1-4 of this invention under different curing agent ratios.

[0023] Figure 5 This is a surface view of the biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared in Examples 5-7 of this invention.

[0024] Figure 6 The surface water flow velocity and drag reduction rate of the biomimetic rigid-elastic coupled microstructure drag-reducing coating prepared in Example 6 of this invention are shown. Detailed Implementation

[0025] The accompanying drawings are for illustrative purposes only and are intended to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0026] The polydimethylsiloxane (PDMS, Dow Corning DC184) used in this invention is available through conventional commercial channels.

[0027] The technical solutions of this application are described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0028] Example 1 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: (1) Pretreatment of stainless steel substrate: Polish the stainless steel sample with sandpaper. Specific steps: Polish the stainless steel substrate sample with 240#, 400#, 800#, 1000# and 1500# wet sandpaper, and put the polished sample into anhydrous ethanol for ultrasonic cleaning for 10 min to remove contaminants on the sample surface.

[0029] (2) Preparation of elastic precursor solution: At room temperature, 2.73 g of polydimethylsiloxane (PDMS) base component and 0.27 g of curing agent were mixed uniformly (at a weight ratio of 10:1), and 0.3 g of magnetic Fe3O4 particles were added to the mixture. After stirring evenly, the mixture was placed in a vacuum drying oven for 15 min to remove air bubbles.

[0030] (3) Preparation of biomimetic rigid-elastic coupling microstructure drag-reducing coating: The elastic precursor solution prepared above was taken out and uniformly coated on the cleaned stainless steel substrate. Then, magnetic field induction and ultraviolet light irradiation were applied to it at the same time. The magnetic field strength was 1.45T and the ultraviolet light wavelength was 365 nm. After curing for 2 h, the biomimetic rigid-elastic coupling microstructure drag-reducing coating was obtained.

[0031] Figure 1 , 2 The images show SEM images of the biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared in this embodiment at 650x magnification and at a specially selected location at 3500x magnification. The images show that the surface of the prepared coating has obvious protrusions due to the action of magnetic particles, and the magnetic particles are evenly distributed, which is at the micrometer scale.

[0032] The contact angle of the water droplet on the biomimetic rigid-elastic coupling microstructure drag-reducing coating prepared in this embodiment is as follows: Figure 3 As shown in the figure, the contact angle of the prepared coating is greater than 110°.

[0033] Example 2 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: At room temperature, 2.67 g of the base component, polydimethylsiloxane (PDMS), was uniformly mixed with 0.33 g of curing agent (at a weight ratio of 8:1), and 0.3 g of magnetic Fe3O4 particles were added to the mixture. After thorough mixing, the mixture was placed in a vacuum drying oven for 10 min to remove air bubbles.

[0034] Other areas not mentioned are the same as in Example 1.

[0035] Example 3 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: At room temperature, 2.7 g of polydimethylsiloxane (PDMS) base component and 0.3 g of curing agent were uniformly mixed (at a weight ratio of 9:1), and 0.3 g of magnetic Fe3O4 particles were added to the mixture. After stirring evenly, the mixture was placed in a vacuum drying oven for 10 min to remove air bubbles.

[0036] Other areas not mentioned are the same as in Example 1.

[0037] Example 4 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: At room temperature, 2.75 g of the base component of polydimethylsiloxane (PDMS) was uniformly mixed with 0.25 g of curing agent (at a weight ratio of 11:1), and 0.3 g of magnetic Fe3O4 particles were added to the mixture. After stirring thoroughly, the mixture was placed in a vacuum drying oven for 10 min to remove air bubbles.

[0038] Other areas not mentioned are the same as in Example 1.

[0039] like Figure 4 As shown, the tensile curves of the biomimetic rigid-elastic coupled microstructure drag-reducing coatings prepared in Examples 1-4 were compared. It can be seen from the figure that the samples under different ratios all have good mechanical properties.

[0040] Example 5 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: (1) Pretreatment of stainless steel substrate: Polish the stainless steel sample with sandpaper. Specific steps: Polish the stainless steel substrate sample with 240#, 400#, 800#, 1000# and 1500# wet sandpaper, and put the polished sample into anhydrous ethanol for ultrasonic cleaning for 20 min to remove contaminants on the sample surface.

[0041] (2) Preparation of elastic precursor solution: At room temperature, 2.73 g of polydimethylsiloxane (PDMS) base component was uniformly mixed with 0.27 g of curing agent, and 0.3 g of carbonyl iron powder (CIP) magnetic particles (at a mass ratio of 10%) were added to the mixture. After stirring evenly, the mixture was placed in a vacuum drying oven for 20 min to remove air bubbles.

[0042] (3) Preparation of biomimetic rigid-elastic coupling microstructure drag-reducing coating: The elastic precursor solution prepared above was taken out and uniformly coated on the cleaned stainless steel substrate. Then, magnetic field induction and ultraviolet light irradiation were applied to it simultaneously, and the substrate was cured for 2.5 h to obtain biomimetic rigid-elastic coupling microstructure drag-reducing coating.

[0043] Example 6 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: At room temperature, 2.73 g of polydimethylsiloxane (PDMS) base component was uniformly mixed with 0.27 g of curing agent, and 0.45 g of carbonyl iron powder (CIP) magnetic particles (15% by mass) were added to the mixture. After stirring evenly, the mixture was placed in a vacuum drying oven for 20 min to remove air bubbles.

[0044] Other areas not mentioned are the same as in Example 5.

[0045] Example 7 A method for preparing a biomimetic rigid-elastic coupling microstructure drag-reducing coating includes the following steps: At room temperature, 2.73 g of polydimethylsiloxane (PDMS) base component was uniformly mixed with 0.27 g of curing agent, and 0.6 g of carbonyl iron powder (CIP) magnetic particles (20% by mass) were added to the mixture. After stirring evenly, the mixture was placed in a vacuum drying oven for 20 min to remove air bubbles.

[0046] Other areas not mentioned are the same as in Example 5.

[0047] Figure 5 The images show the surface of the biomimetic rigid-elastic coupling microstructure drag-reducing coatings prepared in Examples 5-7. As can be seen from the images, protrusions are formed on the surface under the action of magnetic particles, and the rigid-elastic coupling microstructure coatings are successfully prepared. In particular, the surface protrusion effect is the best when the mass fraction of magnetic particles is 15%.

[0048] Figure 6 The surface flow velocity and drag reduction rate curves of the biomimetic rigid-elastic coupled microstructure drag-reducing coating prepared in Example 6 show that, compared with the bare stainless steel substrate, the water flow velocity on the surface of the biomimetic rigid-elastic coupled microstructure coating prepared in this example is faster, and the drag reduction effect is better.

[0049] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating, characterized in that, Includes the following steps: (1) Polish the stainless steel substrate until smooth, ultrasonically clean it, and then dry it for later use. (2) Mix the base components of polydimethylsiloxane and the curing agent evenly; add magnetic particles to the mixture, stir evenly, place in a vacuum drying oven to remove air bubbles, and obtain the elastic precursor solution; (3) After uniformly coating the elastic precursor solution containing magnetic particles onto the surface of the treated stainless steel substrate, magnetic field induction and ultraviolet light irradiation are applied simultaneously; under the action of magnetic field, the magnetic particles are oriented and arranged, and the elastic precursor is cured by ultraviolet light irradiation, and finally a drag-reducing coating with rigid-elastic coupling microstructure is formed on the surface of stainless steel substrate.

2. The method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating according to claim 1, characterized in that, When pre-treating the stainless steel substrate, it is polished with 240#, 400#, 800#, 1000# and 1500# wet sandpaper in sequence, and then ultrasonically cleaned in anhydrous ethanol for 10 to 20 minutes.

3. The method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating according to claim 1, characterized in that, The base component of polydimethylsiloxane and the curing agent are mixed in a weight ratio of 7 to 20:1; the magnetic particles account for 5% to 20% of the mass of the mixture.

4. The method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating according to claim 1, characterized in that, The magnetic particles are made of magnetic Fe3O4 or CIP particles.

5. The method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating according to claim 1, characterized in that, Vacuum the oven at room temperature for 10–20 minutes to remove air bubbles.

6. The method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating according to claim 1, characterized in that, In step (3), the coated stainless steel substrate is placed stably on the magnet to ensure that the contact surface between the substrate and the magnet is intact and free of foreign matter. At the same time, a magnetic field is applied to induce it. The synergistic effect of the two lasts for 1.5 to 2.5 hours to promote the formation of microstructures.

7. The method for preparing a biomimetic rigid-elastic coupled microstructure drag-reducing coating according to claim 1, characterized in that, In step (3), the magnetic field strength of the permanent magnet used is 1.45 T to 1.5 T, and the wavelength of the ultraviolet lamp is 365 nm.

8. A biomimetic rigid-elastic coupling microstructure drag-reducing coating, characterized in that, The coating was prepared using the method described in any one of claims 1-7 for a biomimetic rigid-elastic coupling microstructure drag-reducing coating.

9. The application of the biomimetic rigid-elastic coupling microstructure drag-reducing coating as described in claim 8 in the preparation of hydrophobic and / or drag-reducing materials or material coatings.

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