Bionic three-dimensional magnetic control microstructure super-hydrophobic antifouling surface and preparation method thereof

Abstract

The invention discloses a bionic three-dimensional magnetic control microstructure super-hydrophobic antifouling surface and a preparation method thereof, and belongs to the technical field of structural bionic materials. Inspired by a self-cleaning surface which is swung, swept and driven by a coral tentacle, in order to overcome the limitation of a single anti-fouling strategy and overcome the defects of the prior art in long-term anti-fouling effect, a conical array is designed by taking the coral tentacle as a prototype; the conical array is made of silicone rubber mixed with magnetic particles, and is driven by an external magnetic field to realize directional continuous swinging of the array structure; a rough super-hydrophobic structure is formed on the surface of the conical array through laser etching, the super-hydrophobic structure on the surface achieves a self-cleaning function, adhesion of fouling organisms is effectively reduced through an active driving / passive desorption synergistic effect, intelligent regulation and control of viscosity reduction and desorption are achieved, and the service life of the device is prolonged. The method has the advantages of environmental friendliness, low preparation cost, wide application range, long service life and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of marine antifouling coatings, and specifically relates to a bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface and a preparation method thereof. Background Art

[0002] Marine engineering equipment is an important part of the country's development of high-end equipment manufacturing industry and an important support for the implementation of the strategy of building a strong maritime nation. Marine biofouling caused by the attachment and aggregation of marine microorganisms, animals and plants on the surface of marine engineering equipment affects its service safety, reliability and life. Marine biofouling will increase the roughness of the hull surface, increase the navigation resistance and increase fuel consumption. A 1μm thick biofilm increases the hull resistance by 80% and reduces the navigation speed by 15%. In severe cases, the increase in fuel consumption can reach 40% and the total navigation cost can reach 77%. In addition, the attachment of marine organisms will also lead to a decrease in the effective diameter of the inner wall of the pipeline, a decrease in heat exchange efficiency, accelerated corrosion of the surface of marine equipment, damage to equipment and facilities, increased maintenance costs and reduced safety performance. According to statistics, the overall economic losses caused by marine biofouling such as transportation delays and hull repairs exceed US$150 billion each year. Traditional toxic antifouling technologies are gradually being banned by countries around the world due to their negative impact on the environment. Therefore, it is urgent to develop green, stable and broad-spectrum antifouling coatings to deal with the problem of marine biofouling.

[0003] Antifouling coatings are considered one of the most effective means of fouling protection because of their high efficiency, economy and broad spectrum. Traditional toxic antifouling technologies are gradually being banned by countries around the world due to their negative impacts on the environment. With the rapid development of marine antifouling technology, efficient, environmentally friendly and broad-spectrum bionic marine antifouling strategies have received widespread attention in the industry. Although certain progress has been made in the research of these coatings, the bionic micro-nano antifouling coatings lack broad-spectrum antifouling properties and have defects such as low protection efficiency, making it difficult to prevent fouling organisms from adhering and eroding; low surface energy release coatings have poor static antifouling effects, poor adhesion to the substrate and poor mechanical stability, and cannot achieve long-term and stable protection; bionic dynamic surfaces rely on strong water flow scouring, and cannot adjust the surface state in time in the face of biological adhesion, and the durability of antifouling needs to be improved. Therefore, there is an urgent need to develop new antifouling surfaces that couple long-term, multiple antifouling strategies to address the negative effects of marine biofouling.

[0004] Chinese invention patent 202111481729.1 discloses a preparation method and new antifouling use of bionic hydrophilic magnetically controlled high aspect ratio cilia, which uses the hydrophilic antifouling polymer on the surface to form a hydration layer through charge action or hydrogen bond interaction, reducing the adhesion of bacteria and other microorganisms and organic matter, and performing passive antifouling; at the same time, the magnetically controlled swinging effect given by the magnetic particles enables the cilia themselves to achieve active antifouling. However, since its passive antifouling is achieved by grafting hydrophilic molecules to the surface, it may affect its long-term antifouling effect. Summary of the invention

[0005] Inspired by the self-cleaning surface of coral tentacles that sweep and drive away, in order to overcome the limitations of a single antifouling strategy and solve the shortcomings of existing technologies in long-term antifouling effects, a bionic three-dimensional magnetically controlled microstructured superhydrophobic antifouling surface and its preparation method are proposed.

[0006] The technical solution adopted by the present invention is specifically as follows:

[0007] A bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface, wherein the surface is based on coral tentacles and has a conical array with a bottom diameter of 0.8-1.2 mm, a top diameter of 0.5-0.7 mm, a height of 3-6 mm, and a spacing of 0.8-1.2 mm; the conical array is made of silicone rubber mixed with magnetic particles, and the mass ratio of the silicone rubber to the magnetic particles is 1:(0.5-1); a rough super-hydrophobic structure is formed on the surface of the conical array by laser etching.

[0008] The method for preparing the bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface of the present invention comprises the following specific steps:

[0009] 1) Preparation of bionic antifouling surface mold;

[0010] 2) Preparation of bionic antifouling surfaces;

[0011] 3) Preparation of microstructured superhydrophobic antifouling surfaces;

[0012] The specific method of step 1) is as follows:

[0013] Firstly, a bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface model was designed based on coral tentacles. The model is a conical array with a bottom diameter of 0.8-1.2 mm, a top diameter of 0.5-0.7 mm, a height of 3-6 mm, and a spacing of 0.8-1.2 mm.

[0014] According to the established biomimetic three-dimensional magnetically controlled microstructure super-hydrophobic antifouling surface model, a master plate is obtained by 3D printing technology;

[0015] Then, the obtained master is ultrasonically cleaned, sprayed with a release agent, and dried for later use; then melted paraffin is poured on the surface of the master and solidified at 4°C for 2 hours;

[0016] Finally, the paraffin wax is separated from the master plate vertically to obtain the paraffin wax mold, i.e., the bionic antifouling surface mold.

[0017] The specific method of step 2) is as follows:

[0018] Ethyl acetate is added to silicone rubber, and the mixture is mechanically stirred to obtain a silicone rubber dispersion; the magnetic particles are ultrasonically dispersed, cleaned, and dried for later use; the silicone rubber dispersion is mixed with the magnetic particles, a silicone rubber curing agent is added dropwise, and the mixture is mechanically stirred to obtain a mixed solution; a release agent is sprayed on the surface of a paraffin mold, and the mixture is left to air for later use; the mixed solution is then degassed and poured into a paraffin mold, a permanent magnet is placed under the paraffin mold, and vacuum cured to obtain a bionic antifouling surface; the mass ratio of silicone rubber to magnetic particles in the mixed solution is 1:(0.5-1);

[0019] The specific method of step 3) is as follows: the obtained bionic antifouling surface is cleaned by removing the residual paraffin on the surface, then ultrasonically cleaned, and dried for later use. Then, ultraviolet laser etching is performed, with a processing speed of 600 mm / s, a current of 10 A, and a frequency of 20 Hz, and laser etching is performed 3 times to obtain a microstructured superhydrophobic antifouling surface.

[0020] Preferably, the material of the master plate in step 1) is a high-toughness resin material, such as polyamide, polylactic acid, acrylonitrile-butadiene-styrene, polyetheretherketone, and epoxy resin;

[0021] Preferably, the release agent described in step 1) is a 741 silicone-type release agent.

[0022] Preferably, the silicone rubber model described in step 2) is 9120 type two-component room temperature vulcanized silicone rubber; and the silicone rubber curing agent is tetraethyl orthosilicate.

[0023] Preferably, the magnetic particles in step 2) are ferrosoferric oxide with a particle size of 10 μm.

[0024] Preferably, the permanent magnet in step 2) is a high-strength NdFeB circular permanent magnet with a surface magnetic flux of 0.3T.

[0025] Preferably, the method for removing the paraffin surface residue in step 3) is to use Wujie powder for cleaning.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The antifouling surface described in the present invention utilizes an external magnetic field to drive the bionic antifouling surface array structure to intelligently regulate the swing response, breaking the traditional antifouling method and using a physical antifouling strategy to effectively get rid of the attachment of fouling organisms. In addition, laser etching is used to increase the surface roughness, so that the surface obtains super-hydrophobic and low-adhesion wetting characteristics, effectively realizing surface self-cleaning. The present invention uses non-toxic and environmentally friendly materials, is environmentally friendly, has a low preparation cost, a wide range of applications, a long service life, and multiple antifouling strategies, effectively enhancing the antifouling regulation and application performance of the underwater solid wall surface of marine engineering equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the preparation process

[0029] Figure 2 (a) Schematic diagram of bionic antifouling surface mold structure; (b, c) top view and side view under ultra-depth-of-field microscope; (e, f) top view and side view under scanning electron microscope; (g) droplet transport process

[0030] Figure 3 Wettability of bionic antifouling surfaces before and after laser etching

[0031] Figure 4 The results of coating plates with different attachment times of P. pantotrophus and B. subtilis

[0032] Figure 5 The spectrophotometer measures the optical density of Paracoccus pantrophus and Bacillus subtilis attached to the surface at different times. 600 ;

[0033] Figure 6 Schematic diagram of antifouling mechanism; DETAILED DESCRIPTION

[0034] The technical solution adopted by the present invention is further explained and illustrated in the form of specific embodiments in combination with the accompanying drawings. The silicone rubber in the following embodiments is 9120 type two-component room temperature vulcanized silicone rubber, and the magnetic particles are ferrosoferric oxide with a particle size of 10 μm.

[0035] Example 1

[0036] 1) Preparation of bionic antifouling surface mold

[0037] NXUG software was used to design the structure of the bionic antifouling surface mold and establish a model. The design size of the bionic antifouling surface mold was 50mm×50mm×2mm. The mold was evenly distributed with a conical array structure with a bottom diameter of 1mm, a top diameter of 0.6mm, a height of 5mm, and a spacing of 1mm. The master was obtained by 3D printing SUNLU three-green high-toughness photosensitive resin, such as Figure 2 As shown in a.

[0038] The obtained master was ultrasonically cleaned with anhydrous ethanol for 30 minutes, and then immersed in a mixed solution of detergent and deionized water with a mass ratio of 1:1 for 24 hours, and then dried at room temperature for 12 hours. Spray 741 silicone release agent on the surface of the master, and set it aside after drying. Heat the paraffin at 80°C until it melts, pour it on the surface of the master, heat it at 50°C until the master and the paraffin are completely combined, and place it in a 4°C refrigerator to solidify for 2 hours. Separate the paraffin from the master vertically to obtain a paraffin mold, i.e., a bionic antifouling surface mold.

[0039] 2) Preparation of biomimetic antifouling surfaces

[0040] Spray 741 silicone release agent on the surface of the paraffin mold and let it stand for 15 minutes. Add 2mL of ethyl acetate to 10g of silicone rubber and stir mechanically for 20 minutes to obtain a silicone rubber dispersion; place 10g of ferroferric oxide in 50mL of acetone solution for ultrasonic dispersion for 30 minutes, then wash with deionized water and ethanol, dry in a 50℃ drying oven for 24 hours for standby use. Mix the silicone rubber dispersion with 3g of ferroferric oxide, add 0.1mL of ethyl orthosilicate (silicone rubber curing agent) dropwise, and stir mechanically for 10 minutes. Place the mixed solution in a vacuum drying oven for degassing until no bubbles overflow, take out the solution and pour it into the paraffin mold, compact it with smooth acrylic on the top, and place a permanent magnet (surface magnetic flux is about 0.3T) under the paraffin mold; move the paraffin mold and the permanent magnet to a 50℃ vacuum drying oven for curing for 24 hours to obtain a bionic antifouling surface.

[0041] 3) Preparation of microstructured super-hydrophobic antifouling surface

[0042] The obtained bionic antifouling surface was cleaned with decontamination powder to remove the paraffin residue on the surface, and then ultrasonically cleaned with ethanol for 30 minutes, dried and set aside. Then, the surface was processed by laser etching using an ultraviolet laser marking machine, with the processing speed set to 600 mm / s, the current to 10 A, the frequency to 20 Hz, and laser etching for 3 times to obtain a microstructured superhydrophobic antifouling surface.

[0043] Effect verification

[0044] 1) Surface morphology characterization

[0045] Laser confocal microscopy (LCSM) observation ( Figure 2 (b) and (c) show that the array structure is evenly and regularly distributed on the surface in an upright state. Figure 2 (e), (f)) After laser etching, a rough structure is generated on the top surface of the array structure. This rough structure is conducive to capturing air, reducing the contact area of ​​the liquid-solid interface, and changing the wettability of the surface.

[0046] 2) Surface wettability

[0047] Wettability is the key to determine the antifouling performance of the coating, and its wettability can be evaluated by measuring the water contact angle. Figure 3) is in a hydrophobic high adhesion state, with a surface contact angle of 130° (10μL) and 134° (20μL), making it difficult to achieve surface self-cleaning. The surface state of the droplets after laser etching is in a super-hydrophobic low adhesion state, with a surface contact angle of 157° (10μL) and 161° (20μL), which has a self-cleaning function. The surface microstructure morphology is changed by laser etching of the bionic antifouling surface, the surface roughness is increased, the surface wettability is changed from the Wenzel state to the Cassie-Baxter state, and the wettability of the droplets on the surface is reduced.

[0048] 3) Antifouling performance test

[0049] Bacteria multiply, differentiate and secrete polysaccharide matrix and other substances on the surface of objects, firmly fix on the target surface and continuously form biofilm. Biofilm can provide rich material transportation and effective information transmission for the attachment of small fouling organisms, accelerating the fouling process. Therefore, the Gram-negative bacteria, Paracoccus pantrophus (10 6 cfu / mL), Gram-positive bacteria, Bacillus subtilis (10 6 cfu / mL) was used as a representative of typical fouling organisms to evaluate the antifouling performance of the bionic antifouling surface. The bionic antifouling surface of the present invention was placed in a bacterial solution and the permanent magnet was controlled to swing left and right to achieve the movement of the bionic antifouling surface array structure for 120 hours. The test results are as follows Figure 4 , Figure 5 . Based on the results of the plate spread and OD 600 It can be seen from the values ​​that in the 120h dynamic antifouling performance test, the number of bacteria adhering to the surface of the bionic antifouling coating of the present invention is small and the OD 600 The value is low, showing excellent antifouling performance. The bionic antifouling surface of the present invention can achieve directional swing with the movement of the permanent magnet ( Figure 2 g), and the droplets are in a super-hydrophobic and low-adhesion state on the surface, which effectively reduces the contact area between the bacterial liquid and the surface, laying a solid foundation for anti-fouling adhesion.

[0050] 4) Anti-fouling mechanism

[0051] The array structure of the bionic antifouling surface undergoes directional continuous swinging under the drive of the permanent magnet ( Figure 6 ), effectively repelling and sweeping away fouling organisms approaching the target surface. At the same time, the bionic antifouling surface has super-hydrophobic and low-adhesion wetting properties, which makes the array structure self-cleaning, effectively reducing the contact area between the fouling organisms and the surface, and achieving green and long-term fouling protection.

Claims

1. A bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface, characterized in that: The surface is based on coral tentacles, with a conical array with a bottom diameter of 0.8 to 1.2 mm, a top diameter of 0.5 to 0.7 mm, a height of 3 to 6 mm, and a spacing of 0.8 to 1.2 mm; the conical array is made of silicone rubber mixed with magnetic particles, and the mass ratio of silicone rubber to magnetic particles is 1:(0.5 to 1); a rough superhydrophobic structure is formed on the surface of the conical array by laser etching.

2. The bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface according to claim 1, characterized in that: The magnetic particles are ferroferric oxide with a particle size of 10 μm.

3. The bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface according to claim 1, characterized in that: The silicone rubber is 9120 type two-component room temperature vulcanized silicone rubber.

4. A method for preparing a bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface as claimed in claim 1, characterized in that: The specific steps of this method are as follows: 1) Preparation of bionic antifouling surface mold; 2) Preparation of bionic antifouling surfaces; 3) Preparation of microstructured superhydrophobic antifouling surfaces; Wherein, the specific method of step 1) is as follows: Firstly, a bionic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface model was designed based on coral tentacles. The model is a conical array with a bottom diameter of 0.8-1.2 mm, a top diameter of 0.5-0.7 mm, a height of 3-6 mm, and a spacing of 0.8-1.2 mm. According to the established biomimetic three-dimensional magnetically controlled microstructure super-hydrophobic antifouling surface model, a master plate is obtained by 3D printing technology; Then, the obtained master is ultrasonically cleaned, sprayed with a release agent, and dried for later use; then melted paraffin is poured on the surface of the master and solidified at 4°C for 2 hours; Finally, the paraffin wax is separated from the master plate vertically to obtain the paraffin wax mold, i.e., the bionic antifouling surface mold; The specific method of step 2) is as follows: Ethyl acetate is added to silicone rubber, and the mixture is mechanically stirred to obtain a silicone rubber dispersion; the magnetic particles are ultrasonically dispersed, cleaned, and dried for later use; the silicone rubber dispersion is mixed with the magnetic particles, a silicone rubber curing agent is added dropwise, and the mixture is mechanically stirred to obtain a mixed solution; a release agent is sprayed on the surface of a paraffin mold, and the mixture is left to air for later use; the mixed solution is then degassed and poured into a paraffin mold, a permanent magnet is placed under the paraffin mold, and vacuum cured to obtain a bionic antifouling surface; the mass ratio of silicone rubber to magnetic particles in the mixed solution is 1:(0.5-1); The specific method of step 3) is as follows: The obtained bionic antifouling surface was cleaned by ultrasonic cleaning to remove the residual paraffin on the surface, and then dried for use. Then, ultraviolet laser etching was used, with the processing speed set at 600 mm / s, current 10 A, frequency 20 Hz, and laser etching was performed 3 times to obtain a microstructured superhydrophobic antifouling surface.

5. The method for preparing the bionic three-dimensional magnetically controlled microstructure super-hydrophobic antifouling surface according to claim 4, characterized in that: The material of the master plate described in step 1) is a high-toughness resin material.

6. The method for preparing the bionic three-dimensional magnetically controlled microstructure super-hydrophobic antifouling surface according to claim 5, characterized in that: The high-toughness resin material is one of polyamide, polylactic acid, acrylonitrile-butadiene-styrene, polyetheretherketone, and epoxy resin.

7. The method for preparing a biomimetic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface according to claim 4, characterized in that: The release agent described in step 1) is a 741 silicone-type release agent.

8. The method for preparing the bionic three-dimensional magnetically controlled microstructure super-hydrophobic antifouling surface according to claim 4, characterized in that: The silicone rubber model described in step 2) is 9120 type two-component room temperature vulcanized silicone rubber; the silicone rubber curing agent is tetraethyl orthosilicate.

9. The method for preparing a biomimetic three-dimensional magnetically controlled microstructured super-hydrophobic antifouling surface according to claim 4, characterized in that: The magnetic particles described in step 2) are ferroferric oxide with a particle size of 10 μm.

10. The method for preparing the bionic three-dimensional magnetically controlled microstructure super-hydrophobic antifouling surface according to claim 4, characterized in that: The permanent magnet in step 2) is a high-strength NdFeB circular permanent magnet with a surface magnetic flux of 0.3T.

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