Anti-corrosion self-repairing super-amphiphobic coating film and preparation method thereof

Abstract

The invention discloses an anti-corrosion self-repairing super-amphiphobic coating film and a preparation method thereof, and belongs to the technical field of polymer coating materials. The coating film sequentially comprises a nano particle skeleton layer, a dynamic borate bond layer and a super-amphiphobic functional layer from inside to outside, and the three-layer gradient design synergistically realizes micro / nano structure stability, self-repairing and super-amphiphobic functions. The framework layer takes SiO2-TiO2 composite nanoparticles as a substrate and provides support; the dynamic boric acid ester bond layer forms a dynamic network through polycondensation of an organic boron compound, endows the self-repairing capability and enhances interface bonding; the super-amphiphobic functional layer is formed by grafting a fluorine-containing organosilicon compound and has hydrophobic and oleophobic properties. A multi-layer structure is constructed step by step, the reaction condition is mild, the operation is simple, the cost is low, the method is suitable for large-scale industrial preparation, the coating film has excellent super-amphiphobic performance and interface adhesion performance, the super-amphiphobic performance of the coating film can still be kept stable in long-term use or a complex environment, and the problem that an existing super-amphiphobic material is prone to damage is effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of polymer coating materials technology, specifically relating to an anti-corrosion self-healing superhydrophobic coating and its preparation method. Background Technology

[0002] Wettability is one of the core properties of a material surface, determining the spreading and adhesion of liquids on solid surfaces. Over the past three decades, with breakthroughs in nanotechnology and bionics, wettability control has rapidly progressed from basic theoretical research to functional applications, resulting in extreme wettability surface systems represented by superhydrophobic, superhydrophilic, and superamphophobic surfaces. Traditional superhydrophobic surfaces (contact angle > 150°) achieve efficient water repulsion through biomimetic micro / nanostructures and low surface energy surfaces, such as the surfaces of lotus leaves, butterfly wings, rose petals, water strider legs, and mussels. These superhydrophobic materials show great potential in areas such as self-cleaning, oil-water separation, anti-icing, droplet control, anti-fouling, corrosion prevention, anti-fouling, and drag reduction.

[0003] However, with industrial and technological development, single hydrophobic properties are no longer sufficient to meet the application requirements in complex environments. For example, in scenarios such as oily wastewater treatment, marine biofouling prevention, and metal corrosion protection, the material surface needs to resist the wetting and adhesion of both low surface energy liquids (such as oils and organic solvents) and high surface energy liquids (such as water), i.e., to achieve superhydrophobic / superoleophobic wettability (simultaneously hydrophobic and oleophobic, with contact angles both >150°). However, the promotion of superhydrophobic / superoleophobic materials in practical engineering applications still faces severe challenges. The main technical bottleneck stems from the poor structural stability of the material surface. When materials are exposed to complex environments, mechanical forces or chemical erosion directly affect the material surface, causing not only physical damage to the micro / nano structure but also irreversible changes in the surface chemical composition. This dual destructive effect leads to the gradual decay or even complete failure of the material's inherent superhydrophobic / superoleophobic properties, severely limiting the widespread application of superhydrophobic / superoleophobic materials in practical engineering.

[0004] Therefore, developing superhydrophobic and dihydrophobic materials that combine excellent environmental tolerance with self-healing capabilities has become a key technical challenge in this field. Summary of the Invention

[0005] In view of the fact that single hydrophobic properties are difficult to meet the requirements of complex environments, and that superhydrophobic / superoleophobic materials are damaged by mechanical external forces or chemical erosion when exposed to complex environments in practical engineering applications, resulting in the degradation and failure of superhydrophobic and superoleophobic properties, there is an urgent need to develop superhydrophobic and superoleophobic materials that have both excellent environmental tolerance and self-repair function. The purpose of this invention is to provide a corrosion-resistant and self-repairing superhydrophobic and superoleophobic coating and its preparation method.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a self-healing, anti-corrosion, superhydrophobic coating, which consists of a nanoparticle framework layer, a dynamic borate ester bond layer, and a superhydrophobic functional layer from the inside out. The nanoparticle framework layer is composed of SiO2-TiO2 composite nanoparticles. The dynamic borate ester bond layer is formed on the surface of the SiO2-TiO2 composite nanoparticles by a polycondensation reaction of an organoboron compound. The superhydrophobic functional layer is formed by grafting a fluorinated organosilicon compound onto the dynamic borate ester bond layer through silicon-oxygen bonds.

[0007] The organoboron compound is any one of 1,4-phenyldiboronic acid, 4,4-biphenyldiboronic acid, 1,3,5-phenyltriboronic acid, and 1,3-phenyldiboronic acid.

[0008] Preferably, the organoboron compound is 1,4-phenylenediboronic acid (BDBA).

[0009] The fluorinated organosilicon compound is any one of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrichlorosilane, and trichloro(1H,1H,2H,2H-perfluorooctyl)silane (CAS No. 78560-45-9).

[0010] Preferably, the fluorinated organosilicon compound is 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES).

[0011] The contact angle of the anti-corrosion self-healing superhydrophobic coating is greater than 150°.

[0012] This invention provides a method for preparing the above-mentioned anti-corrosion self-healing superhydrophobic coating, comprising: Step 1: Add organoboron compound and ammonia to the SiO2-TiO2 composite nanoparticle suspension to obtain emulsion 1; Step 2: Fluorine-containing organosilicon compound and ethanol are added sequentially to emulsion 1 to react and obtain emulsion 2; Step 3: Spray emulsion 2 onto the pretreated substrate and cure it to obtain a corrosion-resistant, self-healing, superhydrophobic coating.

[0013] In step 1, the mass ratio of the organoboron compound to the SiO2-TiO2 composite nanoparticles is 1:(2~3), the reaction temperature is 25 ℃~30 ℃, and the reaction time is 4 h~6 h.

[0014] In step 1, tetraethyl orthosilicate, ammonia, and anhydrous ethanol are mixed and reacted using the sol-gel method to obtain a SiO2 emulsion; tetrabutyl titanate is added for ultrasonic-assisted reaction to obtain a SiO2-TiO2 emulsion, which is then dried to obtain SiO2-TiO2 composite nanoparticles; wherein the particle size of the SiO2-TiO2 composite nanoparticles is 20 nm to 100 nm.

[0015] Preferably, the volume ratio of tetraethyl orthosilicate, ammonia, and anhydrous ethanol is 1:(2~6):(4~8); the mixing reaction temperature is 20 ℃~30 ℃, and the time is 4 h~8 h; the volume ratio of tetrabutyl titanate to SiO2 emulsion is 1:(8~12); and the ultrasonic-assisted reaction temperature is 20 ℃~30 ℃, and the time is 8 h~12 h.

[0016] In step 2, the volume ratio of the fluorinated organosilicon compound, emulsion 1, and ethanol is 1:(4~6):(8~12); the reaction temperature is 65 ℃~75 ℃, and the reaction time is 5~7 h.

[0017] In step 3, the substrate pretreatment is as follows: the substrate is ultrasonically cleaned with acetone, anhydrous ethanol and deionized water in sequence and then dried with N2. After that, the substrate is chemically etched in a mixed solution of CuSO4 and NaCl and dried with N2, followed by hydrothermal activation, cleaning and drying.

[0018] The volume ratio of CuSO4 solution to NaCl solution in the CuSO4 and NaCl mixed solution is 1:(0.7~1); the hydrothermal activation temperature is 90 ℃~100 ℃, and the time is 3 min~8 min.

[0019] Preferably, the concentration of the CuSO4 solution is 0.2 mol / L and the concentration of the sodium chloride solution is 3 mol / L.

[0020] Preferably, the substrate is an aluminum sheet.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The anti-corrosion and self-healing superhydrophobic coating provided by this invention addresses the stability and self-healing issues of superhydrophobic materials through a multi-layered composite structure. The nanoparticle framework layer uses SiO2-TiO2 composite nanoparticles as a substrate, leveraging the high specific surface area of ​​SiO2 and the photocatalytic stability of TiO2 to form a support structure with both mechanical strength and chemical inertness, providing physical anchoring points for subsequent functional layers. The dynamic borate ester bond layer forms a dynamic covalent network through the condensation of organoboron compounds on the nanoparticle surface. The reversible breakage-recombination characteristics of its borate ester bonds endow the coating with the ability to self-heal through molecular chain rearrangement when damaged. Simultaneously, this layer serves as an intermediate transition layer, enhancing the interfacial bonding between the framework layer and the functional layers. The superhydrophobic functional layer is directionally grafted onto the surface of the dynamic layer using the silicon-oxygen bonds of fluorinated organosilicon compounds. The low surface energy of the perfluorinated long chains gives the coating both hydrophobic and oleophobic properties, while the chemical stability of the silicon-oxygen bonds ensures the durability of the functional layer in complex environments. The gradient design of the three-layer structure achieves the synergy of micro / nano structure stability, dynamic self-healing capability and superhydrophobic function. The dynamic bond layer is the core innovation, which not only repairs physical damage through reversible chemical bonds, but also maintains the integrity of the multilayer structure through interface enhancement.

[0022] Furthermore, the coating has a contact angle greater than 150° and exhibits extremely low adhesion to both water and oil. It can maintain its superhydrophobic and anti-repellent properties even after mechanical damage or chemical erosion, thus overcoming the technical bottleneck of contact angle attenuation caused by insufficient structural or chemical stability of traditional materials.

[0023] The method for preparing a self-healing superhydrophobic coating provided by this invention achieves synergistic optimization of material properties by constructing a multi-level functional structure in steps. The reaction conditions in each step are mild, the operation is simple, the cost is low, and it is suitable for large-scale industrial preparation. SiO2-TiO2 composite nanoparticles are used as the framework layer, whose high specific surface area and rigid structure provide mechanical support for subsequent functional layers. Dynamic borate ester bond layers are formed through the condensation reaction of organoboron compounds and nanoparticles. The reversible breaking and recombination characteristics of these dynamic chemical bonds endow the coating with self-healing capabilities. By introducing a synergistic reaction between fluorinated organosilicon compounds and ethanol, a superhydrophobic and oleophobic functional layer is formed on the surface of the dynamic bond layer through the directional grafting of silicon-oxygen bonds. The low surface energy of fluorine and the nanostructure work together to achieve superhydrophobic and oleophobic functions. By combining a spraying process with substrate pretreatment technology, the adhesion of the coating is enhanced by controlling surface roughness and chemical activity. The curing process promotes the formation of a stable cross-linked network among the functional layers. The entire preparation process, through the layer-by-layer assembly of nanoparticle framework, dynamic chemical bonds, and superhydrophobic and oleophobic molecules, achieves self-repair capability after coating damage while maintaining superhydrophobic and oleophobic properties. The synergistic effect of these three elements overcomes the technical bottleneck of traditional coatings that are difficult to balance structural stability and functional durability.

[0024] Furthermore, by controlling the mass ratio of organoboron compounds to nanoparticles at 1:(2~3), the grafting of boric acid groups onto the nanoparticle surface is ensured while avoiding side reactions caused by excessive boric acid monomers. A mild reaction temperature of 25-30℃ is selected to meet the activation energy requirements of the polycondensation reaction while avoiding the thermal decomposition of dynamic bonds caused by high temperatures. A reaction time of 4-6 hours is set to ensure the full formation of borate ester bonds while preventing nanoparticle aggregation caused by excessive time. This synergistic control solves the problem of uniform distribution and stable binding of dynamic bond layers at the molecular level, laying the foundation for the stable loading of subsequent superhydrophobic functional layers.

[0025] Furthermore, SiO2-TiO2 composite nanoparticles were constructed using the sol-gel method. Tetraethyl orthosilicate was used as a silicon source precursor, and a hydrolysis-condensation reaction was carried out under ammonia catalysis to form SiO2 nanoparticles. The hydrolysis reaction under this alkaline environment was conducive to the formation of a uniformly dispersed nanoscale SiO2 emulsion. Tetrabutyl titanate was introduced as a titanium source, and under the assistance of ultrasound, the titanate was uniformly dispersed and hydrolyzed to generate TiO2, which formed a heterogeneous composite structure with SiO2. Ultrasonic treatment not only accelerated the hydrolysis kinetics of tetrabutyl titanate, but also achieved uniform composite of SiO2 and TiO2 at the nanoscale through cavitation effect. Finally, composite nanoparticles with a particle size controlled in the range of 20-100 nm were obtained through a drying process. This particle size range can ensure the dense stacking of nanoparticles in the coating to form a stable framework, and also provide sufficient specific surface area for the subsequent construction of dynamic bonding layers. The synergistic effect of the sol-gel method and ultrasound assistance ensures the uniformity of the composite nanoparticles in terms of chemical composition and microstructure, providing a structural basis for the stable construction of the subsequent dynamic borate bond layer and superhydrophobic functional layer.

[0026] Furthermore, by controlling the ratio of fluorinated organosilicon compounds to emulsion 1 and ethanol, as well as specific temperature and time parameters, controllable grafting of the superhydrophobic functional layer is achieved. Under the premise of maintaining the integrity of the micro / nano composite structure, high-density grafting of low surface energy materials is realized, providing a stable basis for the superhydrophobic properties of the coating film. Attached Figure Description

[0027] Figure 1 The infrared spectra of SiO2-TiO2 and SiO2-TiO2-BDBA-PFDTES prepared in Example 1 of the present invention are shown, wherein (a) is the infrared spectrum of SiO2-TiO2 and (b) is the infrared spectrum of SiO2-TiO2-BDBA-PFDTES. Figure 2 The images show the SEM characterization of the surface microstructure of the SiO2-TiO2-BDBA-PFDTES coating in Example 1 of this invention at different magnifications, where a is 36571x and b is 11000x. Figure 3 This is an EDS image of the SiO2-TiO2-BDBA-PFDTES coating surface in Example 1 of the present invention; Figure 4 This is a schematic diagram of the contact angles of water and oil on the SiO2-TiO2-BDBA-PFDTES coating in Example 1 of the present invention, where a is water and b is diiodomethane; Figure 5 This is a schematic diagram of the adhesion between water and oil on the SiO2-TiO2-BDBA-PFDTES coating film in Example 1 of the present invention, where a is water and b is diiodomethane. Figure 6 This is a schematic diagram illustrating the anti-fouling properties of aluminum sheets placed in different solution environments before and after SiO2-TiO2-BDBA-PFDTES treatment in Example 1 of the present invention, where (a) is ink; (b) is milk; (c) is coffee; and (d) is black tea. Figure 7 This is a schematic diagram of the contact angle change curve of the superhydrophobic coating film in strong acid / alkaline solutions in Example 1 of the present invention, wherein (a) is an acidic solution with pH=1; and (b) is an alkaline solution with pH=14. Figure 8 This is a schematic diagram of the contact angle change curve of the SiO2-TiO2-BDBA-PFDTES coating in the self-healing cycle of Example 1 of the present invention; Figure 9 This is a self-healing photograph of the SiO2-TiO2-BDBA-PFDTES coating in Example 1 of the present invention under a fluorescence microscope. Detailed Implementation

[0028] To enable those skilled in the art to understand the features and effects of the present invention, the following descriptions and definitions are only general descriptions of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0029] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0030] Example 1 This embodiment provides a self-healing, anti-corrosion, superhydrophobic coating. The specific preparation method of this self-healing, superhydrophobic coating is as follows: (1) Substrate processing After polishing, the aluminum sheet was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen. The aluminum sheet was then chemically etched for 2 minutes in a mixed solution (5 mL of 0.2 mol / L CuSO4 solution and 5 mL of 3 mol / L NaCl solution), ultrasonically cleaned with deionized water, and dried with nitrogen. The etched aluminum sheet was then hydrothermally activated by heating in a 90 ℃ deionized water bath for 8 minutes to promote the regeneration of surface hydroxyl groups (-OH) and enhance the chemical bonding ability with the coating. After cleaning with anhydrous ethanol, the sheet was dried in a 100 ℃ oven for later use. (2) Synthesis of SiO2-TiO2 composite nanoparticles 12 mL of anhydrous ethanol and 8 mL of ammonia were added to a round-bottom flask, and 2 mL of tetraethyl orthosilicate (TEOS) was added dropwise with slow stirring. The mixture was magnetically stirred at 25 °C for 6 h, and a white SiO2 nanoparticle emulsion was obtained by sol-gel method. 10 mL of the SiO2 nanoparticle emulsion was taken, and 1 mL of tetrabutyl titanate (TBOT) was added. The mixture was ultrasonically dispersed for 10 min and magnetically stirred at 25 °C for 10 h to obtain a SiO2-TiO2 emulsion. TBOT hydrolyzed and condensed on the surface of the SiO2 nanoparticles to form a TiO2 shell. After centrifugation and drying in an oven at 100 °C, SiO2-TiO2 composite nanoparticles were obtained. (3) Synthesis of SiO2-TiO2-BDBA emulsion 0.2 g of SiO2-TiO2 composite nanoparticles and 20 mL of ethanol were added to a round-bottom flask. After ultrasonic stirring for 40 min, 80 mg of 1,4-phenyldiboronic acid (BDBA) and 0.2 mL of ammonia water were added at 27 °C. The mixture was then magnetically stirred for 5 h to obtain a SiO2-TiO2-BDBA emulsion. (4) Synthesis of SiO2-TiO2-BDBA-PFDTES emulsion 5 mL of SiO2-TiO2-BDBA emulsion was added to a round-bottom flask, followed by the addition of 10 mL of ethanol and 1 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES). The mixture was reacted at 70 °C for 6 h to obtain SiO2-TiO2-BDBA-PFDTES emulsion. (5) Coating spraying and curing At a pressure of 0.2 MPa, SiO2-TiO2-BDBA-PFDTES emulsion was sprayed onto an aluminum sheet using a spray gun with a nozzle diameter of 0.3 mm. The emulsion was then cured at 70 °C for 4 h in a drying oven to obtain a corrosion-resistant, self-healing, superhydrophobic (SiO2-TiO2-BDBA-PFDTES) coating. See appendix Figure 1The images show the infrared spectra of the SiO2-TiO2 composite nanoparticles and the SiO2-TiO2-BDBA-PFDTES coating in this embodiment. The infrared spectra are at 1085 cm⁻¹. -1 At 779 cm⁻¹, both samples showed absorption peaks, corresponding to the stretching vibration peak of Si-O-Ti. This indicates that SiO₂ and TiO₂ successfully underwent grafting reactions in both the SiO₂-TiO₂ composite nanoparticles and the SiO₂-TiO₂-BDBA-PFDTES coating, forming Si-O-Ti chemical bonds. -1 The region is Si-C, due to the presence of Si-C bonds in the introduced BDBA or PFDTES molecules. The change in this region compared to the SiO2-TiO2 spectrum indicates the introduction of new substances; at 1193 cm⁻¹... -1 The absorption peak at 1317-1441 cm⁻¹ corresponds to the stretching vibration of the CF bond. Since the PFDTES molecule contains CF bonds, the appearance of this peak indicates that PFDTES has been successfully introduced into the SiO₂-TiO₂ system; the absorption peak at 1317-1441 cm⁻¹ corresponds to the stretching vibration of the CF bond. -1 The appearance of a BO stretching vibration peak indicates that BDBA molecules have successfully participated in the reaction and been introduced into the SiO2-TiO2-BDBA-PFDTES coating system. The above infrared spectroscopy analysis confirms the successful synthesis of the SiO2-TiO2-BDBA-PFDTES coating and clarifies the presence of each chemical bond within it.

[0031] See appendix Figure 2 The image shown is a SEM image of the SiO2-TiO2-BDBA-PFDTES coating prepared in this embodiment. Figure 2 As can be seen, the particles on the coating surface are densely and continuously distributed, forming a rough surface with micro / nano structures. This indicates that during the preparation of the coating, the particles interact well, forming a uniform micro / nano structure. This micro / nano structure can trap air in its gaps. Due to the presence of air, the actual contact area between water / oil and the coating surface is greatly reduced, making the contact between water / oil droplets and the coating surface a Cassie-Baxter wetting state. In the Cassie-Baxter state, the contact angle between the liquid and the solid surface will increase significantly, thereby improving the superhydrophobicity of the coating, that is, the coating has a high contact angle with both water and oil, exhibiting good repulsion. See appendix Figure 3The image shows an EDS scan of the SiO2-TiO2-BDBA-PFDTES coating surface prepared in this embodiment. It can be seen that C, O, Si, Ti, B, and F elements are uniformly distributed on the coating surface. This indicates that during the coating formation process, the components achieved good mixing and dispersion at the molecular level, without significant element aggregation or segregation. Uniform element distribution helps ensure the consistency and stability of the coating performance. O, Si, and Ti elements are mainly provided by SiO2-TiO2 and form the basic framework structure of the coating. B element comes from BDBA, and C and F elements mainly come from PFDTES. Therefore, because PFDTES successfully participates in the reaction and uniformly distributes C and F elements on the coating surface, the surface energy of the coating surface is reduced. A low surface energy surface has the characteristic of repelling liquids (such as water and oil). Combined with the previous analysis of the coating microstructure (micro / nanostructure), this low surface energy characteristic, along with the micro / nanostructure, results in a super-amphiphobic coating surface, meaning it has extremely high contact angles with both water and oil, making it difficult for liquids to wet the coating surface. See attached Figure 4 The contact angles measured by a contact angle meter when water and diiodomethane were dropped onto the SiO2-TiO2-BDBA-PFDTES coating prepared in this embodiment were 168.62° and 155.38°, respectively. Generally, a contact angle greater than 150° is considered to indicate that the material surface possesses superhydrophobic or superoleophobic properties. The experimental results show that the SiO2-TiO2-BDBA-PFDTES coating of this invention exhibits extremely strong water repulsion; water droplets are difficult to spread on the coating surface and exhibit an approximately spherical shape, indicating that the coating has superhydrophobic properties. It also shows good repulsion to diiodomethane, meaning the coating has superoleophobic properties. Combined with the previous analysis of the coating's microstructure (micro / nanostructure) and elemental composition (containing elements such as fluorine that reduce surface energy), this superhydrophobic and superoleophobic property is the result of the combined effect of the coating's microstructure and chemical composition. The micro / nano structure can trap air and reduce the actual contact area between the liquid and the coating surface; while the fluorine element introduced by PFDTES reduces the surface energy of the coating. The synergistic effect of the two makes the coating exhibit good repellency to both water and oil, verifying that the SiO2-TiO2-BDBA-PFDTES coating has good superhydrophobic properties.

[0032] See attached Figure 5The dynamic contact process of water and diiodomethane on the SiO2-TiO2-BDBA-PFDTES coating was observed. When water and diiodomethane came into contact with the coating surface and were pulled upwards, it was found that the water and diiodomethane did not drip onto the SiO2-TiO2-BDBA-PFDTES coating, but rather detached from the coating surface as the syringe was pulled up. This directly indicates that the adhesion between water and diiodomethane and the coating is relatively weak. This further verifies that the SiO2-TiO2-BDBA-PFDTES coating of this invention possesses excellent superhydrophobic and amphoteric properties and low adhesion characteristics.

[0033] See appendix Figure 6 Two aluminum sheets were prepared. One sheet was coated with a SiO2-TiO2-BDBA-PFDTES film, and the other was a pure aluminum sheet as a control sample. The coated and pure aluminum sheets were carefully immersed in different liquids—ink, milk, coffee, and black tea—using tweezers and other tools. During immersion, the immersion speed and angle were kept as consistent as possible to ensure identical experimental conditions. After immersion for a period of time, the aluminum sheets were removed from the liquids, and the degree of contamination on their surfaces was observed and recorded. (See attached...) Figure 6 The results showed that pure aluminum sheets were stained with ink, milk, coffee, and black tea (which produced color), exhibiting corresponding colors and stains; while aluminum sheets coated with SiO2-TiO2-BDBA-PFDTES remained clean (colorless) and were not stained by liquids, indicating that the coating on the aluminum sheets has good anti-fouling properties. See appendix Figure 7 The figures show the changes in the contact angles of water and diiodomethane on the SiO2-TiO2-BDBA-PFDTES coating prepared in this embodiment after immersion in acidic solutions (pH = 1) and alkaline solutions (pH = 14) for different times (0-140 h). As can be seen from the figures, after 140 h of acid and alkali treatment, the contact angles of water and diiodomethane on the coating remained at a high level (greater than 150°), indicating that this embodiment still exhibits superhydrophobic and amphoteric properties in acidic and alkaline environments, demonstrating the good tolerance of the coating to these conditions. This demonstrates the stability and reliability of the SiO2-TiO2-BDBA-PFDTES coating in complex chemical environments. In practical applications, in industrial environments or outdoor settings where contact with acidic or alkaline substances is possible, this coating can maintain its superhydrophobic and amphoteric properties for a long time, effectively preventing liquid contamination and corrosion, and has high practical value. See appendix Figure 8The SiO2-TiO2-BDBA-PFDTES coating prepared in this embodiment was immersed in a solution at pH 14 for 140 h and then subjected to different numbers of 2-h heating repair processes at 30 °C. The changes in the contact angles of water and diiodomethane on the coating were observed. It can be seen that with the increase in the number of repair cycles, the contact angles of water and diiodomethane generally showed some fluctuations, but remained at a relatively high level. This indicates that the heating repair process played a positive role in restoring the superhydrophobic and amphoteric properties of the coating. Heating accelerated the reformation of borate ester bonds, promoting the migration of long fluorocarbon chains from the inside of the coating to the coating surface. These long fluorocarbon chains have low surface energy, replenishing the missing low-surface-energy segments on the coating surface, repairing the damaged surface structure, and thus improving the surface properties of the coating, contributing to the restoration of its superhydrophobic and amphoteric properties. After multiple heating repairs, the coating was able to restore its superhydrophobic and amphoteric properties, indicating that the coating has a certain self-healing ability. This characteristic allows the coating to recover its properties through simple heat treatment after being damaged by the external environment, extending the service life of the coating and increasing its reliability and practicality in practical applications, such as in industrial scenarios where it is susceptible to chemical corrosion or mechanical damage.

[0034] See appendix Figure 9 The coating surface of this embodiment was lightly scratched with a scalpel, and then the coating was heated in an oven at 30°C. The self-healing photograph of the coating under a fluorescence microscope is shown in the attached image. Figure 9 The results showed that the scratches on the coating surface basically disappeared after 2 hours of self-healing. This indicates that the SiO2-TiO2-BDBA-PFDTES coating in this embodiment exhibits good self-healing performance in a heated environment, effectively repairing mechanical damage to the surface. This is mainly because heating promotes the reformation of broken borate ester bonds. Borate ester bonds have a certain degree of dynamic reversibility; under suitable temperature conditions, broken borate ester bonds can be reconnected, thereby repairing the damaged chemical bond structure in the coating. This is an important chemical basis for coating self-healing. Heating enhances the fluidity of the polymer. At higher temperatures, the mobility of polymer molecular chains increases, allowing molecules to move and rearrange more easily, which helps fill damaged areas such as scratches and promotes the self-healing process. The rapid migration of long fluorocarbon chains promotes the formation of molecular chains. Long fluorocarbon chains have lower surface energy and better mobility; under heating conditions, they can migrate to the damaged area more quickly, participate in the reconstruction of molecular chains, and further improve the self-healing efficiency of the coating.

[0035] In summary, the SiO2-TiO2-BDBA-PFDTES coating obtained in Example 1 of this invention has excellent self-healing properties, which gives it greater advantages in practical applications. In situations where it is susceptible to mechanical wear or scratches, the coating can achieve self-repair through simple heat treatment, extending the service life of the coating, reducing maintenance and replacement costs, and broadening its application prospects in fields such as industrial protection and electronic device surface coatings.

[0036] Example 2 This embodiment provides a self-healing, anti-corrosion, superhydrophobic coating. The specific preparation method of this self-healing, superhydrophobic coating is as follows: (1) Substrate processing After polishing, the aluminum sheet was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen. The aluminum sheet was then chemically etched for 2 minutes in a mixed solution (5 mL of 0.2 mol / L CuSO4 solution and 5 mL of 3 mol / L NaCl solution), ultrasonically cleaned with deionized water, and then dried with nitrogen. The aluminum sheet was then hydrothermally activated by heating in a 96 ℃ deionized water bath for 4 minutes, cleaned with anhydrous ethanol, and dried in an oven at 100 ℃. (2) Synthesis of SiO2-TiO2 composite nanoparticles 10 mL of anhydrous ethanol and 6 mL of ammonia were added to a round-bottom flask. 2 mL of tetraethyl orthosilicate (TEOS) was added dropwise with slow stirring. The mixture was magnetically stirred at 30 °C for 4 h, and a white SiO2 emulsion was obtained via sol-gel method. 8 mL of the SiO2 emulsion was taken and added to 1 mL of tetrabutyl titanate (TBOT). The mixture was ultrasonically dispersed for 10 min, and then hydrolyzed and condensed with the -OH groups on the surface of the SiO2 particles. The mixture was magnetically stirred at 20 °C for 11 h to obtain a SiO2-TiO2 emulsion. The emulsion was centrifuged and dried in an oven at 100 °C to obtain SiO2-TiO2 composite nanoparticles. (3) Synthesis of SiO2-TiO2-BDBA emulsion 0.2 g of SiO2-TiO2 composite nanoparticles and 20 mL of ethanol were added to a round-bottom flask and ultrasonically stirred for 40 min. 75 mg of 1,4-phenylenediboric acid (BDBA) and 0.2 mL of ammonia were added at 25 °C and magnetically stirred for 6 h to obtain a SiO2-TiO2-BDBA emulsion. (4) Synthesis of SiO2-TiO2-BDBA-PFDTES emulsion 6 mL of SiO2-TiO2-BDBA emulsion was added to a round-bottom flask, followed by the addition of 12 mL of ethanol and 1 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES). The mixture was reacted at 72 °C for 6 h to obtain the SiO2-TiO2-BDBA-PFDTES emulsion. (5) Coating spraying and curing At a pressure of 0.2 MPa, the SiO2-TiO2-BDBA-PFDTES emulsion was sprayed onto an aluminum sheet using a spray gun with a nozzle diameter of 0.3 mm. The emulsion was then cured at 65 °C for 5 h in a drying oven to obtain a SiO2-TiO2-BDBA-PFDTES coating. In this example, TiO2 particles were generated on the surface of SiO2 particles using a sol-gel method, synthesizing SiO2-TiO2 particles. These SiO2-TiO2 particles reacted with BDBA to form dynamic borate ester bonds. PFDTES was then added to modify the surface of the SiO2-TiO2-BDBA particles, preparing a SiO2-TiO2-BDBA-PFDTES coating. The coating surface exhibited a dense and continuous particle distribution, with contact angles of 167.32° and 154.36° for water and diiodomethane, respectively. Adhesion tests showed that neither water nor diiodomethane dripped onto the coating surface when pulled upwards, indicating relatively low adhesion between water and the coating. After immersion in an acidic solution (pH = 1) for 140 hours, the contact angles between the coating and water and diiodomethane were 161.56° and 151.43°, respectively. After immersion in an alkaline solution (pH = 14) for 140 hours, the contact angles between the coating and water and diiodomethane were 159.57° and 151.68°, respectively. The coating achieved self-healing after heating at 30°C for 2 hours.

[0037] Example 3 This embodiment provides a self-healing, anti-corrosion, superhydrophobic coating. The specific preparation method of this self-healing, superhydrophobic coating is as follows: (1) Substrate processing After polishing, the aluminum sheet was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen. The aluminum sheet was then chemically etched for 2 minutes in a mixed solution (5 mL of 0.2 mol / L CuSO4 solution and 5 mL of 3 mol / L NaCl solution), ultrasonically cleaned with deionized water, and then dried with nitrogen. The aluminum sheet was then hydrothermally activated by heating in a 96 ℃ deionized water bath for 3 minutes, cleaned with anhydrous ethanol, and dried in a 100 ℃ oven. (2) Synthesis of SiO2-TiO2 composite nanoparticles 13 mL of anhydrous ethanol and 9 mL of ammonia were added to a round-bottom flask, and 2 mL of tetraethyl orthosilicate (TEOS) was added dropwise with slow stirring. The mixture was magnetically stirred at 26 °C for 6 h, and a white SiO2 emulsion was obtained by sol-gel method. 8 mL of the SiO2 emulsion was taken and added to 1 mL of tetrabutyl titanate (TBOT). The mixture was ultrasonically dispersed for 10 min, and then hydrolyzed and condensed with the -OH groups on the surface of the SiO2 particles. The mixture was magnetically stirred at 22 °C for 10 h to obtain a SiO2-TiO2 emulsion. After centrifugation and drying in an oven at 100 °C, SiO2-TiO2 composite nanoparticles were obtained. (3) Synthesis of SiO2-TiO2-BDBA emulsion 0.2 g of SiO2-TiO2 composite nanoparticles and 20 mL of ethanol were added to a round-bottom flask and ultrasonically stirred for 40 min. 85 mg of 1,4-phenylenediboric acid (BDBA) and 0.2 mL of ammonia were added at 26 °C and magnetically stirred for 6 h to obtain a SiO2-TiO2-BDBA emulsion. (4) Synthesis of SiO2-TiO2-BDBA-PFDTES emulsion 5 mL of SiO2-TiO2-BDBA emulsion was added to a round-bottom flask, followed by the addition of 10 mL of ethanol and 1 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES). The mixture was reacted at 73 °C for 6 h to obtain the SiO2-TiO2-BDBA-PFDTES emulsion. (5) Coating spraying and curing At a pressure of 0.2 MPa, the SiO2-TiO2-BDBA-PFDTES emulsion was sprayed onto an aluminum sheet using a spray gun with a nozzle diameter of 0.3 mm. The emulsion was then cured at 73 °C for 5 h in a drying oven to obtain a SiO2-TiO2-BDBA-PFDTES coating. In this example, TiO2 particles were generated on the surface of SiO2 particles using a sol-gel method, synthesizing SiO2-TiO2 particles. These SiO2-TiO2 particles reacted with BDBA to form dynamic borate ester bonds. PFDTES was then added to modify the surface of the SiO2-TiO2-BDBA particles, preparing a SiO2-TiO2-BDBA-PFDTES coating. The coating surface exhibited a dense and continuous particle distribution, with contact angles of 168.47° and 155.69° for water and diiodomethane, respectively. Adhesion tests showed that neither water nor diiodomethane dripped onto the coating surface when pulled upwards, indicating relatively low adhesion between water and the coating. After immersion in an acidic solution (pH = 1) for 140 hours, the contact angles of the coating with water and diiodomethane were 163.52° and 152.46°, respectively. After immersion in an alkaline solution (pH = 14) for 140 hours, the contact angles of the coating with water and diiodomethane were 161.73° and 151.12°, respectively. The coating achieved self-healing after heating at 30°C for 2 hours.

[0038] Example 4 This embodiment provides a self-healing, anti-corrosion, superhydrophobic coating. The specific preparation method of this self-healing, superhydrophobic coating is as follows: (1) Substrate processing After polishing, the aluminum sheet was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen. The aluminum sheet was then chemically etched for 2 minutes in a mixed solution (5 mL of 0.2 mol / L CuSO4 solution and 5 mL of 3 mol / L NaCl solution), ultrasonically cleaned with deionized water, and then dried with nitrogen. The aluminum sheet was then hydrothermally activated by heating in a 95 ℃ deionized water bath for 4 minutes, cleaned with anhydrous ethanol, and dried in a 100 ℃ oven. (2) Synthesis of SiO2-TiO2 composite nanoparticles 12 mL of anhydrous ethanol and 8 mL of ammonia were added to a round-bottom flask, and 2 mL of tetraethyl orthosilicate (TEOS) was added dropwise with slow stirring. The mixture was magnetically stirred at 24 °C for 6 h, and a white SiO2 emulsion was obtained by sol-gel method. 9 mL of the SiO2 emulsion was taken and added to 1 mL of tetrabutyl titanate (TBOT). The mixture was ultrasonically dispersed for 10 min, and then hydrolyzed and polycondensed with the -OH groups on the surface of the SiO2 particles. The mixture was magnetically stirred at 26 °C for 10 h to obtain a SiO2-TiO2 emulsion. After centrifugation and drying in an oven at 100 °C, SiO2-TiO2 composite nanoparticles were obtained. (3) Synthesis of SiO2-TiO2-BDBA emulsion 0.2 g of SiO2-TiO2 composite nanoparticles and 20 mL of ethanol were added to a round-bottom flask and ultrasonically stirred for 40 min. 78 mg of 1,4-phenylenediboric acid (BDBA) and 0.2 mL of ammonia were added at 26 °C and magnetically stirred for 5 h to obtain a SiO2-TiO2-BDBA emulsion. (4) Synthesis of SiO2-TiO2-BDBA-PFDTES emulsion 5 mL of SiO2-TiO2-BDBA emulsion was added to a round-bottom flask, followed by the addition of 10 mL of ethanol and 1 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES). The mixture was reacted at 70 °C for 6 h to obtain the SiO2-TiO2-BDBA-PFDTES emulsion. (5) Coating spraying and curing At a pressure of 0.2 MPa, the SiO2-TiO2-BDBA-PFDTES emulsion was sprayed onto an aluminum sheet using a spray gun with a nozzle diameter of 0.3 mm. The emulsion was then cured at 70 °C for 4 h in a drying oven to obtain a SiO2-TiO2-BDBA-PFDTES coating. In this example, TiO2 particles were generated on the surface of SiO2 particles using a sol-gel method, synthesizing SiO2-TiO2 particles. These SiO2-TiO2 particles reacted with BDBA to form dynamic borate ester bonds. PFDTES was then added to modify the surface of the SiO2-TiO2-BDBA particles, preparing a SiO2-TiO2-BDBA-PFDTES coating. The coating surface exhibited a dense and continuous particle distribution, with contact angles of 159.68° and 151.08° for water and diiodomethane, respectively. Adhesion tests showed that neither water nor diiodomethane dripped onto the coating surface when pulled upwards, indicating relatively low adhesion between water and the coating. After immersion in an acidic solution (pH = 1) for 140 hours, the contact angles between the coating and water and diiodomethane were 158.45° and 150.76°, respectively. After immersion in an alkaline solution (pH = 14) for 140 hours, the contact angles between the coating and water and diiodomethane were 157.96° and 150.42°, respectively. The coating achieved self-healing after heating at 30°C for 2 hours.

[0039] Example 5 This embodiment provides a self-healing, anti-corrosion, superhydrophobic coating. The specific preparation method of this self-healing, superhydrophobic coating is as follows: (1) Substrate processing After polishing, the aluminum sheet was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen. The aluminum sheet was then chemically etched for 2 minutes in a mixed solution (5 mL of 0.2 mol / L CuSO4 solution and 5 mL of 3 mol / L NaCl solution), ultrasonically cleaned with deionized water, and then dried with nitrogen. The aluminum sheet was then hydrothermally activated by heating in a 96 ℃ deionized water bath for 5 minutes, cleaned with anhydrous ethanol, and dried in an oven at 100 ℃. (2) Synthesis of SiO2-TiO2 composite nanoparticles 12 mL of anhydrous ethanol and 8 mL of ammonia were added to a round-bottom flask, and 2 mL of tetraethyl orthosilicate (TEOS) was added dropwise with slow stirring. The mixture was magnetically stirred at 25 °C for 6 h, and a white SiO2 emulsion was obtained by sol-gel method. 10 mL of the SiO2 emulsion was taken and added to 1 mL of tetrabutyl titanate (TBOT). The mixture was ultrasonically dispersed for 10 min, and then hydrolyzed and polycondensed with the -OH groups on the surface of SiO2 particles. The mixture was magnetically stirred at 25 °C for 11 h to obtain a SiO2-TiO2 emulsion. After centrifugation and drying in an oven at 100 °C, SiO2-TiO2 composite nanoparticles were obtained. (3) Synthesis of SiO2-TiO2-BDBA emulsion 0.22 g of SiO2-TiO2 composite nanoparticles and 20 mL of ethanol were added to a round-bottom flask and ultrasonically stirred for 40 min. 80 mg of 1,4-phenylenediboric acid (BDBA) and 0.2 mL of ammonia were added at 26 °C and magnetically stirred for 5 h to obtain a SiO2-TiO2-BDBA emulsion. (4) Synthesis of SiO2-TiO2-BDBA-PFDTES emulsion 6 mL of SiO2-TiO2-BDBA emulsion was added to a round-bottom flask, followed by the addition of 12 mL of ethanol and 1 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES). The mixture was reacted at 75 °C for 6 h to obtain the SiO2-TiO2-BDBA-PFDTES emulsion. (5) Coating spraying and curing At a pressure of 0.2 MPa, SiO2-TiO2-BDBA-PFDTES emulsion was sprayed onto an aluminum sheet using a spray gun with a nozzle diameter of 0.3 mm. The emulsion was then cured at 70 °C for 4 h in a drying oven to obtain a corrosion-resistant, self-healing, superhydrophobic SiO2-TiO2-BDBA-PFDTES coating.

[0040] In this example, TiO2 particles were generated on the surface of SiO2 particles using a sol-gel method, synthesizing SiO2-TiO2 particles. These SiO2-TiO2 particles reacted with BDBA to form dynamic borate ester bonds. PFDTES was then added to modify the surface of the SiO2-TiO2-BDBA particles, preparing a SiO2-TiO2-BDBA-PFDTES coating. The coating surface exhibited a dense and continuous particle distribution, with contact angles of 161.08° and 153.57° for water and diiodomethane, respectively. Adhesion tests showed that neither water nor diiodomethane dripped onto the coating surface when pulled upwards, indicating relatively low adhesion between water and the coating. After immersion in an acidic solution (pH = 1) for 140 hours, the contact angles of the coating with water and diiodomethane were 159.28° and 151.46°, respectively. After immersion in an alkaline solution (pH = 14) for 140 hours, the contact angles of the coating with water and diiodomethane were 158.32° and 151.48°, respectively. The coating achieved self-healing after heating at 30°C for 2 hours.

[0041] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A corrosion-resistant, self-healing, superhydrophobic coating, characterized in that, The anti-corrosion, self-healing, superhydrophobic coating consists of a nanoparticle framework layer, a dynamic borate ester bond layer, and a superhydrophobic functional layer, from the inside out. The nanoparticle framework layer is composed of SiO2-TiO2 composite nanoparticles. The dynamic borate ester bond layer is formed on the surface of the SiO2-TiO2 composite nanoparticles by a polycondensation reaction of an organoboron compound. The superhydrophobic functional layer is formed by grafting a fluorinated organosilicon compound onto the dynamic borate ester bond layer through silicon-oxygen bonds.

2. The anti-corrosion self-healing superhydrophobic coating according to claim 1, characterized in that, The organoboron compound is any one of 1,4-phenyldiboronic acid, 4,4-biphenyldiboronic acid, 1,3,5-phenyltriboronic acid, and 1,3-phenyldiboronic acid.

3. The anti-corrosion self-healing superhydrophobic coating according to claim 1, characterized in that, The fluorinated organosilicon compound is any one of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrichlorosilane, and trichloro(1H,1H,2H,2H-perfluorooctyl)silane.

4. The anti-corrosion self-healing superhydrophobic coating according to claim 1, characterized in that, The contact angle of the anti-corrosion self-healing superhydrophobic coating is greater than 150°.

5. A method for preparing a self-healing, anti-corrosion, superhydrophobic coating according to any one of claims 1 to 4, characterized in that, include: Step 1: Add organoboron compound and ammonia to SiO2-TiO2 composite nanoparticle suspension to react and obtain emulsion 1; Step 2: Fluorine-containing organosilicon compound and ethanol are added sequentially to emulsion 1 to react and obtain emulsion 2; Step 3: Spray emulsion 2 onto the pretreated substrate and cure it to obtain a corrosion-resistant, self-healing, superhydrophobic coating.

6. The method for preparing a self-healing, anti-corrosion, superhydrophobic coating according to claim 5, characterized in that, In step 1, the mass ratio of the organoboron compound to the SiO2-TiO2 composite nanoparticles is 1:(2~3), the reaction temperature is 25℃~30℃, and the reaction time is 4 h~6 h.

7. The method for preparing a self-healing, anti-corrosion, superhydrophobic coating according to claim 5, characterized in that, In step 1, the specific preparation steps of the SiO2-TiO2 composite nanoparticles are as follows: tetraethyl orthosilicate, ammonia, and anhydrous ethanol are mixed and reacted using the sol-gel method to obtain a SiO2 emulsion; tetrabutyl titanate is added for ultrasonic-assisted reaction to obtain a SiO2-TiO2 emulsion, which is then dried to obtain SiO2-TiO2 composite nanoparticles; wherein, the particle size of the SiO2-TiO2 composite nanoparticles is 20 nm to 100 nm.

8. The method for preparing a self-healing, anti-corrosion, superhydrophobic coating according to claim 5, characterized in that, In step 2, the volume ratio of the fluorinated organosilicon compound, emulsion 1, and ethanol is 1:(4~6):(8~12); the reaction temperature is 65℃~75℃, and the reaction time is 5 h~7 h.

9. The method for preparing a self-healing, anti-corrosion, superhydrophobic coating according to claim 5, characterized in that, In step 3, the substrate pretreatment is as follows: the substrate is ultrasonically cleaned with acetone, anhydrous ethanol and deionized water in sequence and then dried with N2. After that, the substrate is chemically etched in a mixed solution of CuSO4 and NaCl and dried with N2, followed by hydrothermal activation, cleaning and drying.

10. The method for preparing a self-healing, anti-corrosion superhydrophobic coating according to claim 9, characterized in that, The volume ratio of CuSO4 solution to NaCl solution in the CuSO4 and NaCl mixed solution is 1:(0.7~1); the hydrothermal activation temperature is 90~100℃ and the time is 3~8min.

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