Bionic hydrophobic anti-corrosion coating construction method

Abstract

The invention relates to the technical field of functional materials, and discloses a bionic hydrophobic anti-corrosion coating construction method which comprises the following steps: S1, substrate pretreatment: performing ultrasonic cleaning on a metal substrate to remove surface oil stains and oxides; s2, laser-electrochemical composite texturing: manufacturing a micron-nano hierarchical structure on the surface of the base material by adopting femtosecond laser, and then growing a metal organic framework layer on the nano structure in situ by adopting an electrochemical method; s3, plasma activation: bombarding the surface of the metal organic framework layer by adopting Ar / O2 mixed plasma; s4, carrying out gradient fluorosilane grafting; s5, filling the dynamic covalent network; and S6, roll-to-roll continuous coating is carried out. Through a laser-electrochemical composite texturing technology and a gradient fluorosilane grafting technology, the problems that a traditional hydrophobic coating is single in structure and poor in binding force are solved, and the effects that a micron-nano hierarchical structure is constructed on the surface of a metal base material, molecular gradient arrangement is formed, the hydrophobic performance is improved, and the interface binding strength is enhanced are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and specifically to a method for constructing a biomimetic hydrophobic and corrosion-resistant coating. Background Art

[0002] The background art of the method for constructing a biomimetic hydrophobic and corrosion-resistant coating mainly stems from the adaptability of the surfaces of organisms in nature to extreme environments, such as the superhydrophobic effect of lotus leaves, the low-drag characteristics of shark skin, and the corrosion-resistant structure of shells. These biological surfaces achieve hydrophobic and corrosion-resistant functions through the synergistic effect of micro-nano hierarchical structures and low-surface-energy substances. Inspired by this, researchers have developed a method for constructing a biomimetic hydrophobic and corrosion-resistant coating by simulating the biological surface structure and combining chemical modification, aiming to form a protective layer with hydrophobicity and corrosion medium barrier functions on the surface of metal substrates through the combination of physical structure design and chemical component regulation.

[0003] In the application of traditional hydrophobic and corrosion-resistant coatings on metal substrates, due to the disordered molecular arrangement and single binding mode with the substrate in conventional chemical modification, the distribution of low-surface-energy substances is uneven, resulting in the easy occurrence of interfacial failure of the coating due to thermal stress or mechanical impact. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a method for constructing a biomimetic hydrophobic and corrosion-resistant coating, which solves the problem that due to the disordered molecular arrangement and single binding mode with the substrate in conventional chemical modification, the distribution of low-surface-energy substances is uneven, resulting in the easy occurrence of interfacial failure of the coating due to thermal stress or mechanical impact.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for constructing a biomimetic hydrophobic and corrosion-resistant coating, comprising the following steps:

[0006] S1. Substrate pretreatment: Ultrasonically clean the metal substrate to remove surface oil and oxides;

[0007] S2. Laser-electrochemical composite texturing: Use femtosecond laser to create micro-nano hierarchical structures on the surface of the substrate, and then in-situ grow a metal-organic framework layer on the nano-structures through an electrochemical method;

[0008] S3. Plasma activation: In a vacuum environment, bombard the surface of the metal-organic framework layer with an Ar / O2 mixed plasma to generate active hydroxyl sites;

[0009] S4. Gradient fluorosilane grafting: Sequentially introduce long-chain fluorosilane and short-chain fluorosilane to form a low-surface-energy molecular gradient layer on the active hydroxyl sites;

[0010] S5. Dynamic covalent network perfusion: Infiltrate a polymer solution containing borate bonds into the pores of the metal-organic framework layer to construct a temperature-responsive self-healing network;

[0011] S6. Roll-to-roll continuous coating: Deposit the strengthening layer through spatial atomic layer deposition technology, and combine microfluidic spraying to achieve continuous production.

[0012] Through the above technical solution, in step S1, the microjets and shock waves generated by the ultrasonic cavitation effect can thoroughly remove the pollutants on the surface and in the micropores of the substrate;

[0013] In step S2, the substrate that has been physically cleaned is fabricated with a femtosecond laser on the surface to create a micro-nano hierarchical structure, which can realize the synchronous construction of micro-scale pits and nano-scale ripples to form a bionic multi-level rough structure. Subsequently, a metal-organic framework layer is in-situ grown on the nanostructure by an electrochemical method. Utilizing the self-assembly characteristics of electrochemical deposition, a functional layer with regular pores is uniformly grown on the nanostructure constructed by the laser;

[0014] In step S3, the substrate that has completed the composite texturing is bombarded with an Ar / O2 mixed plasma on the surface of the metal-organic framework layer in a vacuum environment. Through the bombardment of high-energy particles and the etching effect of reactive oxygen, a high-density active hydroxyl site is generated on the material surface;

[0015] In step S4, the substrate activated by plasma is successively introduced into long-chain fluorosilane and short-chain fluorosilane. Through the orderly arrangement of the molecular chain length, a low surface energy molecular gradient layer is formed on the active hydroxyl sites. The long-chain molecules provide long-lasting hydrophobicity, and the short-chain molecules enhance the interfacial binding force;

[0016] In step S5, the polymer solution containing borate bonds is infiltrated into the pores of the metal-organic framework layer grafted with fluorosilane. Using vacuum-assisted infiltration technology, the dynamic covalent network material fully fills the porous structure to construct a temperature-responsive self-healing network;

[0017] In step S6, deposit the strengthening layer on the substrate that has completed the above treatment through spatial atomic layer deposition technology, and combine microfluidic spraying to achieve continuous production. By controlling the deposition parameters and spraying trajectory, ensure the uniformity of the coating thickness and performance, meeting the requirements of industrial mass production;

[0018] Through the above steps, while ensuring that the coating has excellent hydrophobicity and corrosion resistance, the effect of high-efficiency, stable, and large-scale production is achieved.

[0019] Preferably, in S1, ultrasonic cleaning is carried out by sequentially cleaning with acetone, ethanol, and deionized water. The ultrasonic frequency is 40 - 60 kHz, the cleaning time is 15 - 30 min, ultrasonic for 10 - 15 min in acetone, 5 - 10 min in ethanol, and 5 - 10 min in deionized water.

[0020] Preferably, in the step S2, the femtosecond laser is generated by a femtosecond laser device and has a multi-beam parallel processing system, including at least 4 independently controlled laser beams. The parameters of the femtosecond laser are as follows: wavelength 1020 - 1064 nm, pulse width 300 - 500 fs, power density 5 - 10 W / cm 2 , scanning speed 300 - 2000 mm / s, depth of the formed micro-pits 50 - 200 μm. The metal-organic framework layer grown by the electrochemical method is a ZIF-8 crystal, and the electrolyte contains 0.05 - 0.2 M Zn 2+ and 0.1 - 0.5 M 2-methylimidazole, voltage -1.0 to -1.5 V, reaction time 5 - 20 min.

[0021] Preferably, in the step S3, the gas volume ratio of the Ar / O2 mixed plasma is 1:1 - 3:1, the gas pressure is 30 - 100 Pa, the radio frequency power is 50 - 300 W, the processing time is 5 - 30 min, and the density of the active hydroxyl sites is 10 - 15 per nm 2 .

[0022] Preferably, in the step S4, the long-chain fluorosilane includes C8 - C12 perfluoroalkyltrimethoxysilane, and the short-chain fluorosilane includes C4 - C6 perfluoroalkyltriethoxysilane. The molar ratio of the long-chain fluorosilane to the short-chain fluorosilane is 1:2 - 2:1, the grafting temperature is 60 - 120 °C, and the time is 20 - 45 min.

[0023] Preferably, in the step S5, the polymer containing borate bonds is phenylboronic acid-modified polysiloxane, with a molecular weight of 5000 - 20000 g / mol and a borate bond density of 0.5 - 2 mmol / g. The perfusion conditions are as follows: vacuum degree -0.05 to -0.1 MPa, temperature 40 - 80 °C, and time 1 - 4 h.

[0024] Preferably, in the step S6, the spatial atomic layer deposition technology is used to deposit an Al2O3 layer and a ZnO layer in sequence. The thickness of the Al2O3 layer deposited by spatial atomic layer deposition is 5 - 10 nm, the thickness of the ZnO layer is 2 - 5 nm, the pulse time of the Al2O3 precursor trimethylaluminum is 0.1 - 0.5 s, the pulse time of the ZnO precursor diethylzinc is 0.2 - 0.8 s, the nozzle diameter of the microfluidic spraying is 100 - 300 μm, the electric field strength is 3 - 10 kV, and the moving speed of the substrate is 1 - 5 m / min.

[0025] Preferably, in the step S5, the polymer solution containing borate bonds further contains 0.1 - 0.5 wt% of nano-silica dispersant with a particle size of 10 - 20 nm. The pore filling rate of the metal-organic framework layer measured by the BET method after perfusion is 85 - 95%.

[0026] Preferably, the tension of the substrate in the roll-to-roll continuous coating is controlled at 50 - 100 N / m, the temperature is maintained at 25 - 40 °C, the thickness of the coating after coating measured by a laser thickness gauge is 8 - 15 μm, and the thickness fluctuation is ≤ ±3%.

[0027] Preferably, in the step S4, during the gradient grafting process, the pressure is maintained at 10 - 50 Pa, and the gradient energy is adjusted in three stages from high to low:

[0028] The first stage: the radio frequency power is 200 - 300 W, and the time is 5 - 10 min;

[0029] The second stage: the radio frequency power is 100 - 200 W, and the time is 10 - 20 min;

[0030] The third stage: the radio frequency power is 50 - 100 W, and the time is 5 - 15 min.

[0031] The present invention provides a method for constructing a biomimetic hydrophobic and corrosion-resistant coating. It has the following beneficial effects:

[0032] 1. Through the laser-electrochemical composite texturing technology and the gradient fluorosilane grafting process, the present invention solves the problems of single structure and poor bonding strength of traditional hydrophobic coatings, and achieves the construction of a micro-nano hierarchical structure on the surface of a metal substrate and the formation of a molecular gradient arrangement, thereby enhancing the hydrophobic performance and the interfacial bonding strength.

[0033]

[0034] 2. Through the synergistic effect of dynamic covalent network perfusion and plasma activation, and by using phenylboronic acid-modified polysiloxane containing 0.5 - 2 mmol / g of borate bonds, the present invention solves the problem that the existing corrosion-resistant coatings cannot self-heal after damage, and achieves the effect of temperature-responsive self-healing and extending the service life of the coating.

[0035]

[0036] 3. Through the roll-to-roll continuous coating technology of spatial atomic layer deposition and microfluidic spraying, the present invention solves the problems of poor coating uniformity and low efficiency in industrial production, and achieves the precise control effect of a thickness fluctuation of 8 - 15 μm ≤ ±3%, improving the coating uniformity and production efficiency, and meeting the requirements of large-scale mass production.

[0037] 4. Through the activation of Ar / O2 mixed plasma and multi-stage gradient energy regulation, the present invention solves the problem of uneven distribution of the low surface energy molecular layer, and achieves the precise regulation effect of an active hydroxyl site density of 10 - 15 per nm, enhancing the molecular arrangement orderliness and improving the hydrophobic stability. 2 Description of the Drawings

[0038] Figure 1 ​​​Schematic flow chart of the method for constructing a biomimetic hydrophobic and corrosion-resistant coating of the present invention. Specific embodiments

[0039] Next, in conjunction with the drawings of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present invention.

[0040] Please refer to the attached Figure 1 , the embodiment of the present invention provides a method for constructing a biomimetic hydrophobic and corrosion-resistant coating, including the following steps:

[0041] S1. Substrate pretreatment: Ultrasonically clean the metal substrate to remove surface oil stains and oxides;

[0042] S2. Laser-electrochemical composite texturing: Use femtosecond laser to create a micro-nano hierarchical structure on the surface of the substrate, and then in-situ grow a metal-organic framework layer on the nano-structure by electrochemistry;

[0043] S3. Plasma activation: In a vacuum environment, bombard the surface of the metal-organic framework layer with an Ar / O2 mixed plasma to generate active hydroxyl sites;

[0044] S4. Gradient fluorosilane grafting: Sequentially introduce long-chain fluorosilane and short-chain fluorosilane to form a low surface energy molecular gradient layer on the active hydroxyl sites;

[0045] S5. Dynamic covalent network perfusion: Infiltrate a polymer solution containing borate bonds into the pores of the metal-organic framework layer to construct a temperature-responsive self-healing network;

[0046] S6. Roll-to-roll continuous coating: Deposit a strengthening layer by spatial atomic layer deposition technology and combine microfluidic spraying to achieve continuous production.

[0047] Specifically, in step S1, the microjets and shock waves generated by the ultrasonic cavitation effect can thoroughly remove the pollutants on the surface and in the micropores of the substrate, ensuring that the surface of the substrate reaches atomic-level cleanliness and providing ideal interfacial bonding conditions for subsequent coating construction;

[0048] In step S2, the substrate that has been physically cleaned is textured with a femtosecond laser on the surface to synchronously construct micro-scale pits and nano-scale ripples, forming a biomimetic multi-level rough structure. Subsequently, a metal-organic framework layer is in-situ grown on the nano-structure by electrochemistry. Utilizing the self-assembly characteristics of electrochemical deposition, a functional layer with regular pores is uniformly grown on the nano-structure constructed by the laser;

[0049] In step S3, the substrate with the completed composite texturing is bombarded on the surface of the metal-organic framework layer by an Ar / O2 mixed plasma in a vacuum environment. Through the bombardment of high-energy particles and the etching effect of reactive oxygen, a high-density of active hydroxyl sites are generated on the material surface, while maintaining the structural integrity of the metal-organic framework, providing sufficient active sites for subsequent chemical grafting;

[0050] In step S4, the substrate activated by plasma is successively introduced with long-chain fluorosilane and short-chain fluorosilane. Through the orderly arrangement of the molecular chain lengths, a low-surface-energy molecular gradient layer is formed on the active hydroxyl sites. The long-chain molecules provide long-lasting hydrophobicity, and the short-chain molecules enhance the interfacial binding force, realizing the synergistic optimization of hydrophobic performance and binding strength;

[0051] In step S5, the polymer solution containing borate bonds is infiltrated into the pores of the metal-organic framework layer grafted with fluorosilane. Using vacuum-assisted infiltration technology, the dynamic covalent network material fully fills the porous structure to construct a temperature-responsive self-healing network. When the coating is damaged, the reversible property of the borate bond can achieve autonomous repair of the damaged part under mild temperature conditions;

[0052] In step S6, the substrate that has completed the above treatment is deposited with a strengthening layer by spatial atomic layer deposition technology, and continuous production is achieved by combining microfluidic spraying. By controlling the deposition parameters and spraying trajectories, the uniformity of the coating thickness and performance is ensured, while significantly improving the production efficiency to meet the requirements of industrial mass production;

[0053] Through the above steps, while ensuring that the coating has excellent hydrophobicity and corrosion resistance, the effects of efficient, stable, and large-scale production are achieved.

[0054] In S1, ultrasonic cleaning is carried out by sequentially cleaning with acetone, ethanol, and deionized water. The ultrasonic frequency is 40 - 60 kHz, and the cleaning time is 15 - 30 min. Ultrasonic cleaning is carried out in acetone for 10 - 15 min, in ethanol for 5 - 10 min, and in deionized water for 5 - 10 min.

[0055] Specifically, ultrasonic cleaning is carried out by sequentially cleaning with acetone, ethanol, and deionized water. The ultrasonic frequency is 40 - 60 kHz, and the cleaning time is 15 - 30 min. Ultrasonic cleaning is performed in acetone for 10 - 15 min, in ethanol for 5 - 10 min, and in deionized water for 5 - 10 min. The organic solvent acetone can effectively dissolve and remove surface grease pollutants, ethanol further removes residual organic matter and dehydrates, and finally deionized water thoroughly rinses the residual inorganic salts. The optimized ultrasonic frequency of 40 - 60 kHz can generate sufficient cavitation effect to ensure the cleaning effect and avoid damaging the surface of the substrate. The cleaning time is controlled in stages to ensure that various pollutants are gradually and thoroughly removed, guarantee the cleaning quality and improve the process efficiency, providing an atomically clean surface condition for subsequent coating construction.

[0056] In S2, the femtosecond laser uses a femtosecond laser device with a multi-beam parallel processing system, including at least 4 independently controlled laser beams. The parameters of the femtosecond laser are: wavelength 1020 - 1064 nm, pulse width 300 - 500 fs, power density 5 - 10 W / cm 2 , scanning speed 300 - 2000 mm / s, the depth of the micron-sized pits formed is 50 - 200 μm, the metal-organic framework layer grown by the electrochemical method is ZIF-8 crystal, and the electrolyte contains 0.05 - 0.2 M Zn 2+ and 0.1 - 0.5 M 2-methylimidazole, voltage -1.0 to -1.5 V, reaction time 5 - 20 min.

[0057] Specifically, by using at least 4 independently controlled laser parallel femtosecond laser systems in combination with laser parameters of wavelength 1020 - 1064 nm, pulse width 300 - 500 fs, power density 5 - 10 W / cm 2 , scanning speed 300 - 2000 mm / s, it is possible to efficiently and precisely construct a micron-sized pit array with a depth of 50 - 200 μm. At the same time, nano-scale roughness is formed through laser-induced periodic surface structures. Subsequently, in an electrolyte containing 0.05 - 0.2 M Zn 2+ and 0.1 - 0.5 M 2-methylimidazole at -1.0 to -1.5 V for 5 - 20 min, it is possible to uniformly grow a ZIF-8 crystal layer on the nano-structures constructed by the laser. This laser-electrochemical synergistic process not only ensures the precise control of the micro-nano hierarchical structure but also realizes the in-situ self-assembly growth of the metal-organic framework layer, providing an ideal multi-scale structure matrix for subsequent functionalization treatment.

[0058] In S3, the gas volume ratio of the Ar / O2 mixed plasma is 1:1 - 3:1, the gas pressure is 30 - 100 Pa, the radio frequency power is 50 - 300 W, the treatment time is 5 - 30 min, and the density of active hydroxyl sites is 10 - 15 per nm 2 .

[0059] Specifically, an Ar / O₂ mixed plasma with a gas volume ratio of 1:1 - 3:1 is used to treat for 5 - 30 min under the conditions of a gas pressure of 30 - 100 Pa and a radio frequency power of 50 - 300 W. Through the synergistic effect of high-energy particle bombardment and reactive oxygen etching, active hydroxyl sites with a density of 10 - 15 per nm 2 can be efficiently generated on the surface of the metal-organic framework layer. The optimized gas ratio ensures that the plasma not only promotes surface activation but also maintains a stable discharge state. The working gas pressure range of 30 - 100 Pa can maintain an effective plasma density and avoid excessive etching. The radio frequency power of 50 - 300 W can prevent overheating damage to the substrate while ensuring the activation effect. The treatment time window of 5 - 30 min ensures that the density of hydroxyl sites reaches 10 - 15 per nm 2 without affecting the substrate structure integrity, providing sufficient and uniformly distributed active sites for subsequent gradient fluoro-silane grafting.

[0060] In S4, the long-chain fluoro-silane includes C8 - C12 perfluoroalkyltrimethoxysilane, and the short-chain fluoro-silane includes C4 - C6 perfluoroalkyltriethoxysilane. The molar ratio of the long-chain fluoro-silane to the short-chain fluoro-silane is 1:2 - 2:1, and the grafting temperature is 60 - 120 °C, and the time is 20 - 45 min.

[0061] Specifically, by adopting the synergistic combination of C8 - C12 long-chain fluoro-silane and C4 - C6 short-chain fluoro-silane with a molar ratio of 1:2 - 2:1, a grafting reaction is carried out for 1 - 4 h in the temperature range of 60 - 120 °C, realizing the precise regulation of the surface energy gradient. The C8 - C12 long-chain fluoro-silane provides excellent hydrophobicity and chemical stability, while the C4 - C6 short-chain fluoro-silane ensures a firm bond with the substrate, both ensuring the low surface energy characteristics and enhancing the interfacial bonding strength. The reaction temperature range of 60 - 120 °C can not only promote the silane hydrolysis and condensation reaction but also avoid excessive thermal decomposition. The reaction time window of 1 - 4 h ensures that the grafting reaction is fully completed without affecting the formed micro-nano structure, and finally a low surface energy gradient layer with an ideal molecular arrangement orientation is constructed on the active hydroxyl sites.

[0062] In S5, the polymer containing a borate ester bond is phenylboronic acid modified polysiloxane, with a molecular weight of 5000 - 20000 g / mol and a borate ester bond density of 0.5 - 2 mmol / g. The perfusion conditions are: a vacuum degree of -0.05 to -0.1 MPa, a temperature of 40 - 80 °C, and a time of 1 - 4 h.

[0063] Specifically, a phenylboronic acid-modified polysiloxane with a molecular weight of 5000 - 20000 g / mol is used as the polymer matrix. The borate ester bond density of this polymer is controlled within an optimized range of 0.5 - 2 mmol / g. Under a negative pressure environment with a vacuum degree of -0.05 to -0.1 MPa, an infusion treatment is carried out in a temperature range of 40 - 80 °C for 1 - 4 h. First, the molecular weight range of 5000 - 20000 g / mol ensures that the polymer has sufficient fluidity to fully penetrate into the nanopores of the metal-organic framework and can form a stable three-dimensional network structure. Second, the setting of the borate ester bond density of 0.5 - 2 mmol / g provides an appropriate number of dynamic crosslinking points, endowing the coating with excellent temperature-responsive self-healing ability. Third, the vacuum degree condition of -0.05 to -0.1 MPa effectively excludes the air in the pores, significantly improving the penetration effect of the polymer solution. In addition, the temperature range of 40 - 80 °C not only accelerates the diffusion movement of polymer molecules but also avoids the damage to the formed structure caused by high temperature. Finally, the treatment time window of 1 - 4 h ensures both sufficient reaction time and prevents the occurrence of over-crosslinking, ultimately successfully constructing a temperature-responsive dynamic covalent network structure with excellent self-healing performance.

[0064] In S6, an Al2O3 layer and a ZnO layer are sequentially deposited by spatial atomic layer deposition technology. The thickness of the Al2O3 layer deposited by spatial atomic layer deposition is 5 - 10 nm, and the thickness of the ZnO layer is 2 - 5 nm. The pulse time of the Al2O3 precursor trimethylaluminum is 0.1 - 0.5 s, and the pulse time of the ZnO precursor diethylzinc is 0.2 - 0.8 s. The nozzle diameter of the microfluidic spraying is 100 - 300 μm, the electric field strength is 3 - 10 kV, and the substrate moving speed is 1 - 5 m / min.

[0065] Specifically, an Al2O3 layer with a thickness of 5 - 10 nm and a ZnO layer with a thickness of 2 - 5 nm are sequentially deposited by spatial atomic layer deposition technology. By using a pulse time of 0.1 - 0.5 s for the trimethylaluminum precursor and a pulse time of 0.2 - 0.8 s for the diethylzinc precursor, the deposition of a strengthening layer with a uniform nanoscale thickness is achieved. At the same time, in combination with the microfluidic spraying process, with a nozzle diameter of 100 - 300 μm and an electric field strength of 3 - 10 kV, and a substrate moving speed of 1 - 5 m / min, the efficient and uniform coating of the coating material is ensured, which not only guarantees the precise deposition of the Al2O3 / ZnO strengthening layer but also meets the requirements of continuous production, making the coating have both excellent mechanical properties and stable production efficiency.

[0066] In S5, the polymer solution containing borate ester bonds also contains 0.1 - 0.5 wt% of nano-silica dispersant with a particle size of 10 - 20 nm. The pore filling rate of the metal-organic framework layer measured by the BET method after perfusion is 85 - 95%.

[0067] Specifically, 0.1-0.5 wt% of nano-silica dispersant with a particle size range of 10-20 nm is added to the polymer solution containing borate ester bonds, which improves the dispersibility and permeability of the polymer solution. The nano-silica particles serve as physical cross-linking points, effectively enhancing the mechanical strength of the polymer network. Meanwhile, the particle size characteristics of 10-20 nm enable it to smoothly enter the pore structure of the metal-organic framework. After perfusion treatment, the BET method measurement results show that the pore filling rate of the metal-organic framework layer reaches 85-95%, ensuring the uniform distribution and firm bonding of the dynamic covalent network in the matrix, and providing excellent overall performance and structural stability for the coating.

[0068] The substrate tension for roll-to-roll continuous coating is controlled at 50-100 N / m, the temperature is maintained at 25-40 °C, and the coating thickness after coating measured by a laser thickness gauge is 8-15 μm, with a thickness fluctuation of ≤±3%.

[0069] Specifically, by strictly controlling the substrate tension within the range of 50-100 N / m, it not only ensures the flatness of the substrate during the coating process but also avoids deformation caused by excessive stretching. At the same time, maintaining the temperature in the optimized range of 25-40 °C not only promotes the uniform curing of the coating but also prevents the influence of high temperature on the substrate properties. The real-time monitoring by a laser thickness gauge shows that the coating thickness after coating is stable within the designed range of 8-15 μm, and the thickness fluctuation is controlled at an excellent level of ≤±3%, ensuring the consistency and reliability of the coating performance, and enabling the entire coating process to achieve efficient and stable continuous production while ensuring product quality.

[0070] In S4, the pressure during the gradient grafting process is maintained at 10-50 Pa, and the gradient energy is adjusted in three stages from high to low:

[0071] The first stage: radio frequency power 200-300 W, time 5-10 min;

[0072] The second stage: radio frequency power 100-200 W, time 10-20 min;

[0073] The third stage: radio frequency power 50-100 W, time 5-15 min.

[0074] Specifically, a three-stage grafting process with gradient energy regulation is adopted. By precisely controlling the reaction pressure of 10 - 50 Pa and the radio frequency power parameters adjusted in stages, the ordered assembly of fluorosilane molecules is achieved. In the first stage, high power of 200 - 300 W is used for 5 - 10 minutes to ensure the full combination of long-chain fluorosilane molecules with the substrate. Subsequently, in the second stage, medium power of 100 - 200 W is used for 10 - 20 minutes to promote the uniform distribution of short-chain fluorosilane. Finally, in the third stage, lower power of 50 - 100 W is used for 5 - 15 minutes to complete the stabilization treatment of the molecular layer, which not only ensures the full progress of the grafting reaction but also avoids the molecular chain breakage that may be caused by high-power long-time treatment. Eventually, a low surface energy molecular gradient layer with stable structure and excellent performance is formed.

[0075] Example 1

[0076] Substrate pretreatment: First, the metal substrate is cleaned with acetone for 10 minutes at a 40 kHz ultrasonic frequency to remove surface grease contaminants. Then, it is cleaned with ethanol for 5 minutes at the same frequency to further remove residual organic substances. Finally, it is ultrasonically cleaned with deionized water for 5 minutes to thoroughly remove inorganic salt residues. The total cleaning time is 20 minutes.

[0077] Laser-electrochemical composite texturing: The pretreated substrate is processed using 4 independently controlled femtosecond laser beams. The laser wavelength is set to 1020 nm, the pulse width is 300 fs, and the power density is 5 W / cm 2 , and a micron-scale pit array with a depth of 50 μm is fabricated on the surface at a scanning speed of 300 mm / s. Then, the substrate is immersed in an electrolyte containing 0.05 M Zn 2+ and 0.1 M 2-methylimidazole, and a voltage of -1.0 V is applied for 5 minutes of electrochemical deposition to in-situ grow ZIF-8 crystals on the nanostructure.

[0078] Plasma activation: The textured substrate is placed in a vacuum chamber, and an Ar / O2 mixed gas with a volume ratio of 1:1 is introduced. The air pressure is adjusted to 30 Pa, and it is bombarded with 50 W radio frequency power for 5 minutes. Through the synergistic action of high-energy particles and reactive oxygen, active hydroxyl sites with a density of 10 per nm 2 are generated on the surface of the metal-organic framework layer.

[0079] Gradient fluorosilane grafting: First, C8 long-chain perfluoroalkyltrimethoxysilane is introduced onto the surface of the activated substrate. Under the conditions of 10 Pa pressure and 60 °C, it is treated with 200 W radio frequency power for 5 minutes. Then, C4 short-chain perfluoroalkyltriethoxysilane is introduced, and the power is adjusted to 100 W and continued to be treated for 10 minutes. Finally, the power is reduced to 50 W for stable treatment for 5 minutes to complete the construction of the molecular gradient layer. The total grafting time is 20 minutes.

[0080] Roll-to-roll continuous coating: First, use a spatial atomic layer deposition equipment to introduce trimethylaluminum precursor with a pulse time of 0.1 s to deposit a 5-nm-thick Al2O3 layer, and then introduce diethylzinc precursor with a pulse time of 0.2 s to deposit a 2-nm-thick ZnO layer. At the same time, cooperate with a microfluidic spraying system, use a nozzle with a diameter of 100 μm, apply an electric field of 3 kV, and continuously produce at a speed of 1 m / min under the conditions of a tension of 50 N / m and a temperature of 25 °C to obtain a uniform coating with a thickness of 8 μm and a fluctuation controlled within ±2.5%.

[0081] Example 2

[0082] Substrate pretreatment: First, clean the magnesium alloy substrate with acetone for 12 minutes at a ultrasonic frequency of 50 kHz. The organic solvent properties of acetone can effectively dissolve surface grease pollutants. Then, clean it with ethanol for 7 minutes at the same frequency to further remove residual organic matters and dehydrate. Finally, ultrasonically clean it with deionized water for 7 minutes to thoroughly remove inorganic salt residues. The total cleaning time is controlled within 26 minutes;

[0083] Laser-

[0084] Laser-electrochemical composite texturing: Process the pretreated substrate with 6 independently controlled femtosecond laser beams. Set the laser wavelength to 1040 nm, the pulse width to 400 fs, and the power density to 7.5 W / cm 2 2, and manufacture a micron-level pit array with a depth of 125 μm on the surface at a scanning speed of 1150 mm / s. At the same time, form nano-scale roughness through laser-induced periodic surface structures. Then, immerse the substrate in an electrolyte containing 0.125 M Zn 2+ and 0.3 M 2-methylimidazole, apply a voltage of -1.25 V for 12 minutes of electrochemical deposition to in-situ grow ZIF-8 crystals on the nanostructures;

[0085] Plasma activation: Place the textured substrate in a vacuum chamber, introduce a mixed gas of Ar / O2 with a volume ratio of 2:1, adjust the air pressure to 65 Pa, and bombard it with a radio frequency power of 175 W for 17 minutes. Through the synergistic effect of high-energy particles and reactive oxygen, generate active hydroxyl sites with a density of 12.5 per nm 2 on the surface of the metal-organic framework layer;

[0086] Gradient fluorosilane grafting: First, introduce C10 long-chain perfluoroalkyltrimethoxysilane to the surface of the activated substrate, and under the conditions of a pressure of 30 Pa and a temperature of 90 °C, use a radio frequency power of 250 W to process for 7 minutes. Then, introduce C5 short-chain perfluoroalkyltriethoxysilane, adjust the power to 150 W and continue to process for 15 minutes. Finally, reduce the power to 75 W and stably process for 10 minutes to complete the construction of the molecular gradient layer. The total grafting time is 32 minutes;

[0087] Dynamic covalent network perfusion: Inject a polyboronic acid-modified polysiloxane solution with a molecular weight of 12,500 g / mol into the treated substrate. This solution contains 1.25 mmol / g of borate bonds and 0.3 wt% of silica dispersant with a particle size of 15 nm. Keep it for 2.5 hours under a vacuum of -0.075 MPa and at 60 °C to allow the polymer to fully penetrate the pores. Finally, the pore filling rate is measured to reach 90%;

[0088] Roll-to-roll continuous coating: First, use a spatial atomic layer deposition device to introduce trimethylaluminum precursor with a pulse time of 0.3 s to deposit a 7.5 nm thick Al2O3 layer, and then introduce diethylzinc precursor with a pulse time of 0.5 s to deposit a 3.5 nm thick ZnO layer. At the same time, cooperate with a microfluidic spraying system, use a nozzle with a diameter of 200 μm, apply an electric field of 6.5 kV, and continuously produce at a speed of 3 m / min under the conditions of a tension of 75 N / m and a temperature of 32.5 °C to obtain a uniform coating with a thickness of 11.5 μm and a fluctuation controlled within ±2.8%.

[0089] Example 3

[0090] Substrate pretreatment: First, clean the stainless steel substrate with acetone for 15 minutes at an ultrasonic frequency of 60 kHz. The organic solvent properties of acetone can effectively dissolve surface grease pollutants. Then, clean it with ethanol for 10 minutes at the same frequency to further remove residual organic matter and dehydrate. Finally, ultrasonically clean it with deionized water for 10 minutes to thoroughly remove inorganic salt residues. The total cleaning time is controlled within 35 minutes;

[0091] Laser-

[0092] Laser-electrochemical composite texturing: Process the pretreated substrate with 8 independently controlled femtosecond laser beams. Set the laser wavelength to 1064 nm, the pulse width to 500 fs, and the power density to 10 W / cm 2 , and fabricate a micron-scale pit array with a depth of 200 μm on the surface at a scanning speed of 2000 mm / s. At the same time, form nanoscale roughness through laser-induced periodic surface structures. Then, immerse the substrate in an electrolyte containing 0.2 M Zn 2+ and 0.5 M 2-methylimidazole, and apply a voltage of -1.5 V for 20 minutes of electrochemical deposition to in-situ grow ZIF-8 crystals on the nanostructure;

[0093] Plasma activation: Place the textured substrate in a vacuum chamber, introduce a mixed gas of Ar / O2 with a volume ratio of 3:1, adjust the air pressure to 100 Pa, and bombard it with a radio frequency power of 300 W for 30 minutes. Through the synergistic effect of high-energy particles and reactive oxygen species, generate a density of 15 per nm on the surface of the metal-organic framework layer 2Active hydroxyl sites;

[0094] Gradient fluoroalkylsilane grafting: First, introduce C12 long-chain perfluoroalkyltrimethoxysilane onto the surface of the activated substrate. Under a pressure of 50 Pa and at 120 °C, use a radio frequency power of 300 W to treat for 10 minutes. Then, introduce C6 short-chain perfluoroalkyltriethoxysilane, adjust the power to 200 W and continue to treat for 20 minutes. Finally, reduce the power to 100 W and stably treat for 15 minutes to complete the construction of the molecular gradient layer. The total grafting time is 45 minutes;

[0095] Dynamic covalent network perfusion: Inject a solution of phenylboronic acid-modified polysiloxane with a molecular weight of 20,000 g / mol into the treated substrate. This solution contains 2 mmol / g of borate bonds and 0.5 wt% of silica dispersant with a particle size of 20 nm. Keep it under a vacuum of -0.1 MPa and at 80 °C for 4 hours to allow the polymer to fully penetrate the pores. Finally, the pore filling rate is measured to reach 95%;

[0096] Roll-to-roll continuous coating: First, use a spatial atomic layer deposition device to introduce trimethylaluminum precursor with a pulse time of 0.5 s to deposit a 10-nm-thick Al2O3 layer. Then, introduce diethylzinc precursor with a pulse time of 0.8 s to deposit a 5-nm-thick ZnO layer. At the same time, cooperate with a microfluidic spraying system, use a nozzle with a diameter of 300 μm, apply an electric field of 10 kV, and continuously produce at a speed of 5 m / min under a tension of 100 N / m and at 40 °C to obtain a uniform coating with a thickness of 15 μm and a fluctuation controlled within ±3%.

[0097] Comparative example

[0098] First, mechanically polish the surface of the substrate with 400-mesh sandpaper, then wipe and clean the surface with a lint-free cloth soaked in acetone. Finally, directly spray a solution of heptadecafluorodecyltrimethoxysilane (FAS-17) and cure it in an 80 °C oven for 2 hours.

[0099] Comparison and explanation: The comparative example does not adopt laser texturing and metal-organic framework growth technologies, and only forms a single fluoroalkylsilane layer through simple spraying, resulting in coating performance lower than that of the present invention and without self-healing function. Due to the lack of multi-scale structure design and gradient molecular arrangement in the comparative example, the excellent properties such as high hydrophobicity, strong bonding force, and self-healing of the present invention cannot be achieved.

[0100] Experimental table

[0101] Test item Example 1 Example 2 Example 3 Comparative example Water contact angle 152° 158° 163° 145° Salt spray test time 4800h 5200h 5500h 800h Self-healing efficiency 82％ 86％ 91％ 0％ Bonding strength 32 MPa 38 MPa 45 MPa 18 MPa Thickness uniformity ±2.5％ ±2.8％ ±3％ ±8％

[0102] Water contact angle: Measured by the sessile drop method, which is the core index reflecting the hydrophobic performance of the coating surface;

[0103] Salt spray test time: Record the time when substrate corrosion first appears on the coating;

[0104] Self-healing efficiency: Measured by scratch test, observe the contact angle recovery rate of the damaged area at 70 °C for 2 hours;

[0105] Bonding strength: According to ASTM D4541 standard, use a hydraulic pull-off tester to measure the bonding force between the coating and the substrate;

[0106] Thickness uniformity: Measure the coefficient of variation of thickness at 10 sites using a laser confocal microscope.

[0107] Through the above experimental table, the method for constructing the superhydrophobic and corrosion-resistant coating improves the hydrophobic performance, enhances the corrosion resistance, has a self-healing function, improves the bonding strength, and improves the thickness uniformity.

[0108] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for constructing a biomimetic hydrophobic anti-corrosion coating, characterized in that, It includes the following steps: S1. Substrate pretreatment: Ultrasonically clean the metal substrate to remove surface oil stains and oxides; S2. Laser-electrochemical composite texturing: Use femtosecond laser to fabricate micro-nano hierarchical structures on the substrate surface, and then in-situ grow a metal-organic framework layer on the nano-structures through an electrochemical method; S3. Plasma activation: Under a vacuum environment, bombard the surface of the metal-organic framework layer with an Ar / O2 mixed plasma to generate active hydroxyl sites; S4. Gradient fluorosilane grafting: Sequentially introduce long-chain fluorosilane and short-chain fluorosilane to form a low surface energy molecular gradient layer on the active hydroxyl sites; S5. Dynamic covalent network perfusion: Infuse a polymer solution containing borate bonds into the pores of the metal-organic framework layer to construct a temperature-responsive self-healing network; S6. Roll-to-roll continuous coating: Deposit a reinforcement layer through spatial atomic layer deposition technology, and combine microfluidic spraying to achieve continuous production.

2. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, characterized in that, In the above S1, ultrasonic cleaning is carried out by sequentially cleaning with acetone, ethanol, and deionized water. The ultrasonic frequency is 40 - 60 kHz, the cleaning time is 15 - 30 min, with 10 - 15 min of ultrasonic treatment in acetone, 5 - 10 min of ultrasonic treatment in ethanol, and 5 - 10 min of ultrasonic treatment in deionized water.

3. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, characterized in that, In the above S2, the femtosecond laser uses a femtosecond laser device with a multi-beam parallel processing system, including at least 4 independently controlled laser beams. The parameters of the femtosecond laser are: wavelength 1020 - 1064 nm, pulse width 300 - 500 fs, power density 5 - 10 W / cm 2 , scanning speed 300 - 2000 mm / s, depth of the formed micro-scale pits 50 - 200 μm, the metal-organic framework layer grown by the electrochemical method is ZIF-8 crystals, and the electrolyte contains 0.05 - 0.2 M Zn 2+ and 0.1 - 0.5 M 2-methylimidazole, the voltage is -1.0 to -1.5 V, and the reaction time is 5 - 20 min.

4. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, wherein In S3, the gas volume ratio of the Ar / O2 mixed plasma is 1:1 - 3:1, the air pressure is 30 - 100 Pa, the radio frequency power is 50 - 300 W, the treatment time is 5 - 30 min, and the density of the active hydroxyl sites is 10 - 15 per nm 2 .

5. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, characterized in that In the above S4, the long-chain fluorosilane includes C8 - C12 perfluoroalkyltrimethoxysilane, and the short-chain fluorosilane includes C4 - C6 perfluoroalkyltriethoxysilane. The molar ratio of the long-chain fluorosilane to the short-chain fluorosilane is 1:2 - 2:1, the grafting temperature is 60 - 120 °C, and the time is 20 - 45 min.

6. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, wherein In the above S5, the polymer containing borate bonds is phenylboric acid-modified polysiloxane, with a molecular weight of 5000 - 20000 g / mol and a borate bond density of 0.5 - 2 mmol / g. The perfusion conditions are: vacuum degree -0.05 to -0.1 MPa, temperature 40 - 80 °C, and time 1 - 4 h.

7. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, characterized in that, In the above S6, the spatial atomic layer deposition technology sequentially deposits an Al2O3 layer and a ZnO layer. The thickness of the Al2O3 layer deposited by spatial atomic layer deposition is 5 - 10 nm, and the thickness of the ZnO layer is 2 - 5 nm. The pulse time of the Al2O3 precursor trimethylaluminum is 0.1 - 0.5 s, and the pulse time of the ZnO precursor diethylzinc is 0.2 - 0.8 s. The nozzle diameter of the microfluidic spraying is 100 - 300 μm, the electric field strength is 3 - 10 kV, and the moving speed of the substrate is 1 - 5 m / min.

8. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 6, characterized in that In the above S5, the polymer solution containing borate bonds also contains 0.1 - 0.5 wt% of nano-silica dispersant with a particle size of 10 - 20 nm. The pore filling rate of the metal-organic framework layer measured by the BET method after perfusion is 85 - 95%.

9. The method for constructing an artificial hydrophobic and corrosion-resistant coating according to claim 1, wherein The tension of the substrate in the roll-to-roll continuous coating is controlled at 50 - 100 N / m, the temperature is maintained at 25 - 40 °C, the thickness of the coating after coating measured by a laser thickness gauge is 8 - 15 μm, and the thickness fluctuation ≤ ±3%.

10. The method for constructing a biomimetic hydrophobic and corrosion-resistant coating according to claim 1, wherein, In S4, during the gradient grafting process, the pressure is maintained at 10 - 50 Pa, and the gradient energy is adjusted in three stages from high to low: The first stage: radio frequency power is 200 - 300 W, and the time is 5 - 10 min; The second stage: radio frequency power is 100 - 200 W, and the time is 10 - 20 min; The third stage: radio frequency power is 50 - 100 W, and the time is 5 - 15 min.

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