Intelligent response type self-repairing anti-corrosion super-hydrophobic composite coating and preparation method thereof

Abstract

The invention discloses an intelligent response type self-repairing anti-corrosion super-hydrophobic composite coating and a preparation method thereof, and belongs to the technical field of functional protective coatings, the coating comprises a polymer binder matrix, and super-hydrophobic functional particles and multifunctional microcapsules dispersed in the polymer binder matrix; the multifunctional microcapsule is provided with a capsule wall and a capsule core; and the capsule core simultaneously contains a repairing agent for repairing physical damage and a corrosion inhibitor for inhibiting corrosion of the substrate. When the coating is subjected to external mechanical damage, the microcapsules are broken, two active substances are synchronously released, healing of physical scratches and targeted corrosion inhibition of an exposed metal substrate are achieved, and a dual repair mechanism is formed. The super-hydrophobic passive shielding function and the intelligent response active protection function after damage are combined, a full-time-domain and multi-layer protection system is constructed, the reliability of the protection coating in a severe service environment is remarkably improved, and the service life of the protection coating in the severe service environment is remarkably prolonged. The method has important application value in the fields of aerospace, ocean engineering, transportation and the like.

Description

Technical Field

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

[0002] Corrosion of metallic materials in natural and industrial environments is a widespread and serious problem, causing enormous economic losses and safety hazards. Applying protective coatings is currently one of the most common and economical methods for metal corrosion protection. Among them, superhydrophobic coatings are considered an important development direction for next-generation high-performance anti-corrosion coatings because they can effectively isolate water and corrosive media from contact with the metal substrate, forming an "air cushion" of protection. However, existing superhydrophobic coatings are essentially still passive protection systems. They rely on the integrity of the coating's physical barrier. In actual use environments, coatings inevitably develop microcracks or scratches due to scratches, impacts, or abrasion. Once the coating is damaged, even with minor damage, the metal substrate will be directly exposed to the corrosive environment, leading to severe localized corrosion and potentially causing large-area peeling of the coating, rendering the entire protective system ineffective.

[0003] To address the failure problem following coating damage, researchers have proposed the concept of self-healing coatings. Among these, self-healing systems based on microencapsulation technology have attracted widespread attention. This technology involves encapsulating a repair agent within microcapsules; when the coating is damaged, the microcapsules rupture, releasing the repair agent to heal the damage. However, most existing self-healing coatings primarily focus on healing physical damage, neglecting the immediate corrosion risk faced by the exposed metal substrate during the "window period" between damage occurrence and repair completion. Simply repairing physical cracks cannot effectively inhibit existing localized corrosion.

[0004] Therefore, how to organically integrate the three functions of efficient passive shielding, timely physical damage repair, and immediate active corrosion inhibition into a coating system to construct an "intelligent" protective coating that can cope with complex damage environments is a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide an intelligent responsive self-healing anti-corrosion superhydrophobic composite coating and its preparation method, so as to solve the technical problem that existing protective coatings are prone to failure after damage.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a smart responsive self-healing anti-corrosion superhydrophobic composite coating, comprising: A polymer binder matrix, and superhydrophobic functional particles and multifunctional microcapsules dispersed in the polymer binder matrix; The multifunctional microcapsule comprises: a capsule wall and a core encapsulated by the capsule wall; the core contains both a repair agent for repairing physical damage and a corrosion inhibitor for inhibiting substrate corrosion.

[0007] Preferably, the repair agent is selected from at least one of epoxy resin, isocyanate, unsaturated polyester, drying oil, microcrystalline wax and organosiloxane prepolymer.

[0008] Preferably, the corrosion inhibitor is selected from at least one of benzotriazole, mercaptobenzothiazole, rare earth salts, phosphates and molybdates.

[0009] Preferably, the capsule wall is selected from polyurea-formaldehyde resin, melamine resin, gelatin, polyurethane, or polystyrene.

[0010] Preferably, the superhydrophobic functional particles are metal-organic framework particles with surfaces modified with low surface energy materials, silica particles with surfaces modified with low surface energy materials, titanium dioxide particles with surfaces modified with low surface energy materials, or zinc oxide particles with surfaces modified with low surface energy materials.

[0011] This invention also discloses a method for preparing the above-mentioned intelligent responsive self-healing anti-corrosion superhydrophobic composite coating, comprising the following steps: 1) By using microencapsulation technology, repair agents and corrosion inhibitors are mixed and coated into the capsule wall material for polymerization reaction to prepare multifunctional microcapsules; 2) The nanoparticles were dispersed in an organic solvent, and after the addition of a low surface energy substance to carry out a surface energy modification reaction, they were separated and dried to prepare superhydrophobic functional particles. 3) Mix and disperse the multifunctional microcapsules obtained in step 1), the superhydrophobic functional particles obtained in step 2), and the polymer binder, and prepare a coating slurry by mechanical stirring and ultrasonic dispersion; 4) Apply the coating slurry to the surface of the substrate and cure it to obtain a smart responsive self-healing anti-corrosion superhydrophobic composite coating.

[0012] Preferably, in step 1), the microencapsulation technology is interfacial polymerization, in-situ polymerization, or complex coagulation; the conditions for the polymerization reaction include: adjusting the pH value to 3.0-3.5, the reaction temperature to 50-80℃, and the reaction time to 2-8h.

[0013] Preferably, in step 2), the nanoparticles are metal-organic framework particles, silica particles, titanium dioxide particles, or zinc oxide particles. The organic solvent is ethanol, n-hexane, or toluene; The low surface energy substance is at least one of long-chain alkylsilanes, fluoroalkylsilanes and long-chain fatty acids; The conditions for surface energy modification reactions include: reaction at 70-100℃ for 6-12 h.

[0014] Preferably, in step 3), the mass ratio of the polymer binder, superhydrophobic functional particles, and multifunctional microcapsules is 100:(5-20):(5-30) by mass parts. The mechanical stirring time is 10-60 min; the ultrasonic dispersion time is 10-60 min.

[0015] Preferably, in step 4), the application method includes: spraying, brushing, or scraping; The curing method is room temperature curing or heat curing; the curing time is 0.5-72 hours.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a smart, responsive, self-healing, anti-corrosion, and superhydrophobic composite coating, comprising: a polymer binder matrix, and superhydrophobic functional particles and multifunctional microcapsules dispersed in the polymer binder matrix; the multifunctional microcapsules include: a capsule wall and a core encapsulated by the capsule wall; the core simultaneously contains a repair agent for repairing physical damage and a corrosion inhibitor for inhibiting substrate corrosion; the multifunctional microcapsules with a core containing both repair agent and corrosion inhibitor are designed so that a single response behavior (microcapsule rupture) can trigger two different repair paths, thereby achieving smart response and dual repair, all-time protection, high compatibility, and design flexibility. When the coating is subjected to physical damage such as scratches or abrasion, the stress at the damage site causes the capsule wall of the multifunctional microcapsule to rupture, and the core material rapidly flows to the damaged area under capillary action. After the repair agent (such as epoxy resin) flows out, it reacts and cures with moisture and oxygen in the air or a curing agent in the coating matrix, or recrystallizes through solvent evaporation, thereby filling the scratches and restoring the physical integrity and barrier function of the coating. The corrosion inhibitor is released simultaneously and selectively adsorbed onto the fresh surface of the metal substrate exposed by damage, forming a dense monomolecular protective film. This film significantly inhibits anodic dissolution (metal ionization) or cathodic hydrogen evolution / oxygen reduction reactions, thereby actively and targetedly preventing the initiation and development of electrochemical corrosion. The repair agent heals the physical barrier, preventing further intrusion of corrosive media; the corrosion inhibitor provides chemical protection at metal interfaces that may not be fully covered or have been covered by the repair agent. Both work synergistically on the same damaged area to provide effective protection. Before damage, superhydrophobic functional particles construct a micro-nano rough structure on the coating surface and are modified with low surface energy materials, giving the coating superhydrophobicity (high water contact angle, low roll-off angle). This effectively repels water droplets and electrolytes, reducing their contact area and adhesion time with the coating surface, providing excellent passive physical shielding. When damage occurs, the multifunctional microcapsules rupture, initiating a dual repair process, switching the protection from shielding mode to active repair mode. After damage, the repair agent solidifies and rebuilds the physical barrier, while the corrosion inhibitor continues to provide chemical protection. This constitutes a complete protective chain encompassing prevention (superhydrophobicity), response (microcapsule rupture), and repair (a combination of physical and chemical methods). It integrates three functions: passive physical shielding, damage self-repair, and active corrosion inhibition. When the coating is damaged, it can simultaneously release a repair agent to heal the physical damage and a corrosion inhibitor to actively suppress substrate corrosion.

[0017] Furthermore, epoxy resins and isocyanates are low-viscosity liquids or prepolymers with good flowability, facilitating release from microcapsules and spreading to fill scratches. Most contain active groups, allowing them to polymerize and cure under moisture, heat, or latent curing agents, forming a robust repair that ensures strength and durability. Microcrystalline waxes and organosiloxanes, on the other hand, can form hydrophobic repair layers through phase transitions or crosslinking.

[0018] Furthermore, benzotriazole and mercaptobenzothiazole are highly efficient corrosion inhibitors for copper and copper alloys, forming coordinate bonds with the metal surface through heteroatoms (N, S) and adsorbing to form a film. Rare earth salts, phosphates, and molybdates are environmentally friendly anodic or mixed corrosion inhibitors suitable for steel, aluminum alloys, etc., promoting the formation or repair of passivation films on metal surfaces. They can be effectively encapsulated in microcapsules, are compatible with repair agents, and have high corrosion inhibition efficiency on the target metal, achieving active inhibition of substrate corrosion.

[0019] Furthermore, materials such as polyurea-formaldehyde resin, melamine resin, and polyurethane possess moderate mechanical strength, ensuring that the microcapsules remain intact during coating processing and service, while also effectively rupturing under stress. The capsule wall thickness and permeability can be precisely controlled through methods such as interfacial polymerization and in-situ polymerization, thereby regulating the release behavior of the core material.

[0020] Furthermore, nano- or micro-sized particles such as metal-organic frameworks (MOFs), SiO2, TiO2, and ZnO can easily achieve low surface energy through surface modification (such as silanization and fluorination). The deposition of these particles in the coating can form stable micro / nano secondary rough structures, which is key to obtaining stable superhydrophobicity. TiO2 and ZnO themselves possess certain photocatalytic or antibacterial properties, which can additionally endow the coating with special functions.

[0021] This invention discloses a method for preparing the aforementioned intelligent responsive self-healing anti-corrosion superhydrophobic composite coating. Through microencapsulation technology, the repair agent and corrosion inhibitor are co-encapsulated within the same capsule wall. This achieves dual repair functionality, ensuring that the two active substances are co-encapsulated and stored in isolation, releasing simultaneously only upon damage. By modifying the surface energy of the nanoparticles and chemically grafting low surface energy substances, the surface energy of the particles is fundamentally reduced, thereby forming an effective hydrophobic rough structure in the coating. Mechanical stirring combined with ultrasonic dispersion is used to mix the microcapsules, superhydrophobic particles, and polymer binder. This prevents the aggregation of particles and microcapsules, ensuring uniform distribution within the coating, thus ensuring consistent and reliable protective and repair functions in any area. While achieving strong dispersion, controlling the process intensity and time maximizes the preservation of the integrity of the brittle microcapsules and the surface modification layer of the superhydrophobic particles, avoiding premature damage or failure of functional components during the preparation stage. Through application and curing, the polymer binder forms a continuous phase, anchoring the functional components within it. After curing, the polymer provides the coating with basic mechanical strength and adhesion. Microcapsules and superhydrophobic particles are securely embedded in the matrix, preventing them from easily detaching during service. Simultaneously, the capsule walls are exposed to stress transmission paths for timely damage response. The entire method is clearly defined, utilizing mature technologies in materials science and engineering, exhibiting good process compatibility and reproducibility.

[0022] Furthermore, the polymerization reaction conditions include: adjusting the pH to 3.0-3.5, a reaction temperature of 50-80℃, and a reaction time of 2-8 hours. Under these conditions, the prepolymer can crosslink at a suitable rate, forming a capsule wall with uniform wall thickness, dense structure, and moderate mechanical strength. The dense capsule wall effectively isolates and protects the internal repair agents and corrosion inhibitors, preventing slow leakage or premature reaction during storage or coating curing. The moderate wall thickness and strength allow the microcapsules to remain intact during conventional processing and to be effectively triggered by stress when the coating is damaged, achieving the ideal responsiveness of being stable when necessary and breaking when necessary.

[0023] Furthermore, the heating and sufficiently long reaction time provide the necessary activation energy and sufficient reaction time for the hydrolysis of low surface energy substances and the condensation dehydration of hydroxyl groups on the particle surface, promoting the formation of strong covalent bonds. The low surface energy molecular layer grafted through strong chemical bonding is very strong and is not easily detached due to friction or solvent action during subsequent dispersion, coating, or use, thus ensuring the long-lasting and stable hydrophobic barrier performance of the coating. Sufficient reaction ensures that the modifier molecules form a dense and uniform monolayer or polymer layer on the particle surface, minimizing surface energy and avoiding localized hydrophilic points caused by uneven modification.

[0024] Furthermore, the functionality and mechanical properties of the coating are balanced by controlling the mass ratio of functional components to binder. This ensures that the coating contains a sufficient number of microcapsules and superhydrophobic particles to provide comprehensive protection and repair capabilities, while guaranteeing that the polymer matrix can firmly encapsulate them, maintaining the coating's basic adhesion, flexibility, and strength. By controlling the mechanical stirring and ultrasonic dispersion time, uniform mixing is achieved while maximizing the protection against premature breakage of microcapsules and the peeling of the surface modification layer of superhydrophobic particles.

[0025] Furthermore, the variety of application methods broadens the application scenarios, enabling its use on a wide range of substrates, from large structures to precision components. Room temperature curing or optimized heat curing conditions can prevent excessively high temperatures from causing softening of the microcapsule walls, premature reaction or volatilization of the core material, and also prevent the decomposition of the superhydrophobic modified layer, thus protecting the integrity of functional components during the film formation stage. Sufficient curing time ensures that the polymer reaches the expected mechanical strength and chemical resistance, ensuring that the coating can withstand external stress and effectively transfer stress to the microcapsules to trigger repair. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0029] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0030] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0031] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0032] In this invention, unless otherwise specified, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply a shortened representation of these numerical combinations.

[0033] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0034] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0035] In this invention, unless otherwise stated, the various reaction or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0036] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0037] This invention provides an intelligent responsive self-healing anti-corrosion superhydrophobic composite coating, which is composed of a polymer binder matrix, superhydrophobic functional particles, and multifunctional microcapsules; Superhydrophobic functional particles are particles with micro-nano rough structures and whose surfaces are modified with low surface energy materials; Multifunctional microcapsules have a capsule wall-core structure, and the core contains both repair agents and corrosion inhibitors.

[0038] Furthermore, the repair agent is selected from substances that can break and flow out under external force and solidify to fill the damaged area, such as epoxy resin, isocyanate, unsaturated polyester, drying oil (such as linseed oil, tung oil), microcrystalline wax or organosiloxane prepolymer.

[0039] Furthermore, the corrosion inhibitor is selected from substances that can be released from the ruptured microcapsules and migrate to the exposed metal substrate surface to form a protective film, such as benzotriazole (BTA) and its derivatives, mercaptobenzothiazole (MBT), rare earth salts (such as cerium nitrate and cerium chloride), phosphates, molybdates, etc.

[0040] Furthermore, the capsule wall material of the multifunctional microcapsule is selected from one or more of polyurea-formaldehyde resin (PUF), melamine resin (MF), gelatin, polyurethane, and polystyrene.

[0041] Furthermore, the superhydrophobic functional particles are selected from one or more of the following: metal-organic framework (MOF) particles with micro-nano structures, silica particles, titanium dioxide particles, and zinc oxide particles.

[0042] Furthermore, the low surface energy material is selected from one or more of long-chain alkylsilanes, fluoroalkylsilanes, and long-chain fatty acids.

[0043] This invention also provides a method for preparing the above-mentioned intelligent responsive self-healing anti-corrosion superhydrophobic composite coating, comprising the following steps: 1) Preparation of multifunctional microcapsules: A mixture containing repair agents and corrosion inhibitors is used as the core through interfacial polymerization, in-situ polymerization or complex coagulation; the pH value is adjusted to 3.0-3.5, the reaction temperature is 50-80℃, and the reaction time is 2-8h; the polymerization reaction is carried out in a polymer monomer or prepolymer solution to form multifunctional microcapsules with the core encapsulated by the capsule wall; 2) Preparation of superhydrophobic functional particles: Nanoparticles with micro / nano structures are prepared and reacted with low surface energy substances to hydrophobize their surfaces; the nanoparticles are dispersed in an organic solvent, and a low surface energy substance is added to carry out a surface energy modification reaction. After separation and drying, superhydrophobic functional particles are prepared; the nanoparticles are metal-organic framework particles, silica particles, titanium dioxide particles, or zinc oxide particles; the organic solvent is ethanol, n-hexane, or toluene; the low surface energy substance is at least one of long-chain alkylsilanes, fluoroalkylsilanes, and long-chain fatty acids; the surface energy modification reaction conditions include: reaction at 70-100℃ for 6-12 h; 3) Preparation of coating slurry: The multifunctional microcapsules prepared in step 1), the superhydrophobic functional particles prepared in step 2), and the polymer binder are mixed in a solvent and dispersed by mechanical stirring and ultrasonication to obtain a uniform and stable coating slurry; the mass ratio of polymer binder, superhydrophobic functional particles and multifunctional microcapsules is 100:(5-20):(5-30); the mechanical stirring time is 10-60 min; the ultrasonic dispersion time is 10-60 min. 4) Coating application and curing: Apply the coating slurry from step 3) evenly to the substrate surface by spraying, brushing or scraping, and then cure it into a film; the curing method is room temperature curing or heat curing; the curing time is 0.5-72h.

[0044] The intelligent responsive self-healing anti-corrosion superhydrophobic composite coating disclosed in this invention has the following effects: (1) Intelligent response and dual repair: When the coating is damaged, the microcapsules rupture and release repair agents and corrosion inhibitors at the same time, achieving "healing" of physical damage and "inhibition" of electrochemical corrosion, providing dual and synergistic protection.

[0045] (2) All-time protection: Combining the excellent passive shielding capability of the superhydrophobic coating with the intelligent response and repair capability after damage, it constructs an all-time, multi-level protection system from "before damage" to "after damage", which greatly improves the reliability and service life of the coating in practical applications.

[0046] (3) High compatibility and design flexibility: The microcapsule system of the present invention is compatible with a variety of superhydrophobic systems and polymer binders. By selecting different repair agents, corrosion inhibitors and particles, flexible functional design can be carried out for different metal substrates and service environments.

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] Example 1 This embodiment provides a smart responsive self-healing anti-corrosion superhydrophobic composite coating based on polyurethane (PU) containing (epoxy resin + benzotriazole) microcapsules and ZIF-67 hydrophobic particles.

[0049] 1) Preparation of multifunctional microcapsules: In a beaker, 5 g of E-51 epoxy resin and 0.5 g of benzotriazole (BTA) were mixed evenly to form the oil phase (capsule core). In another beaker, 2.5 g of gum arabic was dissolved in 50 mL of deionized water to prepare a 2% dispersant solution. The oil phase was slowly added dropwise to the dispersant solution, and high-speed shear emulsification was performed for 1 h to form a stable O / W emulsion. Subsequently, 5 g of urea and 0.5 g of ammonium chloride were added, and the temperature was raised to 60 °C. 12.5 g of 37% formaldehyde aqueous solution was slowly added dropwise to adjust the pH to 3.0-3.5, and the reaction was carried out at this temperature for 4 h. After cooling to room temperature, the capsules were filtered, washed, and dried to obtain multifunctional microcapsules coated with polyurea-formaldehyde (PUF) capsule walls.

[0050] 2) Preparation of superhydrophobic ZIF-67 particles: 1.0 g of ZIF-67 nanoparticles were dispersed in 50 mL of ethanol, and 0.5 g of dodecyltrimethoxysilane (DTMS) was added. The mixture was refluxed at 70 °C for 6 h. After centrifugation, washing, and drying, hydrophobic superhydrophobic ZIF-67 particles were obtained.

[0051] 3) Preparation of coating slurry: 1.0 g of hydrophobic ZIF-67 particles and 1.5 g of multifunctional microcapsules were added to 10.0 g of two-component polyurethane varnish, and stirred at high speed with a mechanical stirrer for 30 min, followed by ultrasonic dispersion for 30 min to obtain a uniform slurry.

[0052] 4) Coating application: The slurry is evenly sprayed onto the sandblasted Q235 carbon steel plate and cured at room temperature for 48 hours to obtain the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating.

[0053] See Figure 1 This is a flowchart illustrating the preparation process of the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating of the present invention. As shown in the diagram, the preparation method of the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating of the present invention includes: firstly, preparing multifunctional microcapsules (containing repair agents and corrosion inhibitors) and superhydrophobic functional particles (after surface low-energy modification), these two being the core functional components of the coating. These are then mixed with a polymer binder to form the base slurry of the coating; this step is a crucial step in integrating the functional components with the substrate material. After the mixed slurry undergoes application and curing steps, the target product, the intelligent responsive self-healing anti-corrosion coating, is finally formed.

[0054] Example 2 This embodiment provides a smart responsive self-healing anti-corrosion superhydrophobic composite coating based on epoxy resin (EP) containing (linseed oil + cerium nitrate) microcapsules and SiO2 hydrophobic particles.

[0055] 1) Preparation of multifunctional microcapsules: 8 g of flaxseed oil and 0.8 g of cerium nitrate powder were mixed evenly to form the core. The capsule wall was prepared using the gelatin-gum arabic coagulation method. The core was emulsified in a gelatin aqueous solution, and after adjusting the pH value, a gum arabic solution was added to allow the complex to coagulate on the surface of the oil droplets. Finally, it was cross-linked and cured with glutaraldehyde to obtain multifunctional microcapsules.

[0056] 2) Preparation of superhydrophobic SiO2 particles: 1.0 g of fumed silica (particle size approximately 15 nm) was dispersed in 50 mL of n-hexane, and 0.8 g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS-13) was added. The mixture was refluxed at 80 °C for 8 h. After centrifugation, washing, and drying, superhydrophobic SiO2 particles were obtained.

[0057] 3) Preparation of coating slurry: 1.0 g of hydrophobic SiO2 particles and 2.0 g of multifunctional microcapsules were added to 12.0 g of two-component epoxy resin (the main agent and the curing agent amine were mixed in proportion) and stirred evenly to obtain a uniform slurry.

[0058] 4) Coating application: The slurry is applied to the aluminum alloy plate by brushing and cured at 80°C for 2 hours to obtain a smart responsive self-healing anti-corrosion superhydrophobic composite coating.

[0059] Example 3 This embodiment provides a coating based on acrylic resin containing (isocyanate + mercaptobenzothiazole) microcapsules and TiO2 hydrophobic particles.

[0060] 1) Preparation of multifunctional microcapsules: 6 g of isocyanate prepolymer (such as Desmodur N3300) was mixed with 0.6 g of mercaptobenzothiazole (MBT) as the core. Interfacial polymerization was used, with ethylenediamine as the aqueous reactant monomer, to form a polyurea capsule wall at the oil / water interface, which encapsulated the core, thus obtaining multifunctional microcapsules.

[0061] 2) Preparation of superhydrophobic TiO2 particles: 1.0 g of P25 type TiO2 nanoparticles and 0.5 g of lauric acid were refluxed in toluene at 100℃ for 12 h to obtain superhydrophobic TiO2 particles.

[0062] 3) Preparation of coating slurry: The above-mentioned hydrophobic particles and microcapsules are mixed and dispersed with thermoplastic acrylic resin in ethyl acetate solvent to obtain a uniform slurry.

[0063] 4) Coating application: The copper sheet is immersed in the slurry using the dip coating method, and then dried in the air to form a film, thus obtaining the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating.

[0064] Example 4 This embodiment illustrates the preparation of a microcapsule coating containing only a repair agent. The preparation process is essentially the same as in Example 1, except that in step (1), the core consists only of 5 g of E-51 epoxy resin, without any added corrosion inhibitors. Subsequent steps are identical.

[0065] Example 5 This embodiment illustrates the preparation of a microcapsule coating containing only a corrosion inhibitor. The preparation process is essentially the same as in Example 1, except that in step (1), the core is composed of an inert carrier oil (such as paraffin oil) and 0.5 g of benzotriazole, without the addition of any curable repair agent. Subsequent steps are identical.

[0066] Example 6 This embodiment provides a polyurethane (PU) based coating containing microcapsules (microcrystalline wax + sodium molybdate) and ZIF-8 hydrophobic particles.

[0067] 1) Preparation of multifunctional microcapsules: 5g of microcrystalline wax was melted by heating and mixed evenly with 0.5g of sodium molybdate to form the core. The core was emulsified by high-speed shearing in an aqueous solution containing gum arabic using an in-situ polymerization method. Then, 5g of urea and 0.5g of ammonium chloride were added, and the system temperature was controlled at 50℃. 12.5g of formaldehyde aqueous solution was slowly added dropwise to adjust the pH to 3.0, and the reaction was carried out at this temperature for 8 hours. After cooling, the mixture was filtered, washed, and dried to obtain multifunctional microcapsules.

[0068] 2) Preparation of superhydrophobic ZIF-8 particles: 1.0 g of ZIF-8 nanoparticles were dispersed in 50 mL of toluene, and 0.5 g of octadecyltrichlorosilane was added. The mixture was refluxed at 70 °C for 12 h. After centrifugation, washing, and drying, hydrophobic superhydrophobic ZIF-8 particles were obtained.

[0069] 3) Preparation of coating slurry: Based on 100g of two-component polyurethane varnish, add 5g of hydrophobic ZIF-8 particles and 5g of multifunctional microcapsules. Stir at low speed with a mechanical stirrer for 10 min, and then disperse with low-power ultrasonication for 10 min to obtain a uniform slurry.

[0070] 4) Coating application: Apply the slurry evenly to the polished 304 stainless steel plate and cure at room temperature for 72 hours to obtain the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating.

[0071] Example 7 This embodiment provides a coating based on epoxy resin (EP) containing (isocyanate + rare earth cerium chloride) microcapsules and silica hydrophobic particles.

[0072] 1) Preparation of multifunctional microcapsules: 10g of isocyanate prepolymer and 3g of cerium chloride powder were mixed evenly to form the core. Interfacial polymerization was used, with ethylenediamine as the aqueous reactant. The core was emulsified in water, heated to 80℃, and an aqueous ethylenediamine solution was added to adjust the pH to 3.5. The reaction was carried out rapidly at this temperature for 2 hours. After cooling, the mixture was filtered, washed, and dried to obtain multifunctional microcapsules.

[0073] 2) Preparation of superhydrophobic SiO2 particles: 1.0 g of fumed silica was dispersed in 50 mL of n-hexane, and 1.0 g of fluoroalkylsilane was added. The mixture was refluxed at 100 °C for 6 h. After centrifugation, washing, and drying, hydrophobic superhydrophobic SiO2 particles were obtained.

[0074] 3) Preparation of coating slurry: Based on 100g of two-component epoxy resin, add 20g of hydrophobic SiO2 particles and 30g of multifunctional microcapsules. Stir at high speed with a mechanical stirrer for 60 min, and then disperse with high-power ultrasonication for 60 min to obtain a uniform slurry.

[0075] 4) Coating application: Spray the slurry evenly onto the aviation aluminum alloy plate, place it in an oven and heat it rapidly at 120℃ for 0.5h (30 minutes) to obtain the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating.

[0076] Example 8 This embodiment provides a smart responsive self-healing anti-corrosion superhydrophobic composite coating based on epoxy resin (EP), containing microcapsules of (unsaturated polyester + zinc dihydrogen phosphate) and hydrophobic zinc oxide particles.

[0077] 1) Preparation of multifunctional microcapsules: In a beaker, 7 g of unsaturated polyester and 0.7 g of zinc dihydrogen phosphate (phosphate) were mixed evenly to form the oil phase (capsule core). In another beaker, 2.5 g of gum arabic was dissolved in 50 mL of deionized water to prepare a 2% dispersant solution. The oil phase was slowly added dropwise to the dispersant solution, and high-speed shear emulsification was performed for 1 h to form a stable O / W emulsion. Subsequently, 5 g of urea and 0.5 g of ammonium chloride were added, and the temperature was raised to 65 °C. 12.5 g of 37% formaldehyde aqueous solution was slowly added dropwise to adjust the pH to 3.2, and the reaction was carried out at this temperature for 5 h. After cooling to room temperature, the capsules were filtered, washed, and dried to obtain multifunctional microcapsules coated with polyurea-formaldehyde (PUF) capsule walls.

[0078] 2) Preparation of superhydrophobic zinc oxide particles: 1.0 g of zinc oxide nanoparticles were dispersed in 50 mL of n-hexane, and 0.6 g of dodecyltriethoxysilane (DTES, long-chain alkylsilane) was added. The mixture was refluxed at 85 °C for 9 h. After centrifugation, washing, and drying, hydrophobic superhydrophobic zinc oxide particles were obtained.

[0079] 3) Preparation of coating slurry: 1.2 g of hydrophobic zinc oxide particles and 1.8 g of multifunctional microcapsules were added to 10.0 g of two-component epoxy resin, stirred at high speed with a mechanical stirrer for 40 min, and then ultrasonically dispersed for 40 min to obtain a uniform slurry.

[0080] 4) Coating application: Apply the slurry evenly to the polished Q235 carbon steel plate and heat it at 60℃ for 4 hours to obtain the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating.

[0081] Example 9 This embodiment provides a smart responsive self-healing anti-corrosion superhydrophobic composite coating based on thermoplastic acrylic resin (PA), containing microcapsules of (organosiloxane prepolymer + disodium hydrogen phosphate) and hydrophobic silica particles.

[0082] 1) Preparation of multifunctional microcapsules: In a beaker, 9 g of organosiloxane prepolymer and 0.9 g of disodium hydrogen phosphate (phosphate) were mixed evenly to form the oil phase (capsule core). In another beaker, 2.5 g of dispersant was dissolved in 50 mL of deionized water to prepare a 2% dispersant solution. The oil phase was slowly added dropwise to the dispersant solution, and high-speed shear emulsification was performed for 1 h to form a stable O / W type emulsion. Subsequently, melamine resin prepolymer was added, the temperature was raised to 70℃, the pH was adjusted to 3.3, and the reaction was carried out at this temperature for 6 h. After cooling to room temperature, the microcapsules were filtered, washed, and dried to obtain multifunctional microcapsules coated with melamine resin capsule walls.

[0083] 2) Preparation of superhydrophobic silica particles: 1.0 g of fumed silica was dispersed in 50 mL of toluene, and 0.7 g of fluoroalkylsilane was added. The mixture was refluxed at 90 °C for 10 h. After centrifugation, washing, and drying, hydrophobic superhydrophobic silica particles were obtained.

[0084] 3) Preparation of coating slurry: 1.5 g of hydrophobic silica particles and 2.2 g of multifunctional microcapsules were added to 10.0 g of thermoplastic acrylic resin, stirred at high speed with a mechanical stirrer for 35 min, and then ultrasonically dispersed for 35 min to obtain a uniform slurry.

[0085] 4) Coating application: Apply the slurry evenly to the polished aluminum alloy plate and cure at room temperature for 24 hours to obtain the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating.

[0086] Example 10 This embodiment provides a smart responsive self-healing anti-corrosion superhydrophobic composite coating based on polyurethane (PU), containing microcapsules of (E-51 epoxy resin + benzotriazole) and hydrophobic ZIF-67 particles (containing two parallel groups: polyurethane capsule wall and polystyrene capsule wall).

[0087] 1) Preparation of multifunctional microcapsules: In a beaker, 6 g of E-51 epoxy resin and 0.6 g of benzotriazole (BTA) were mixed evenly as the oil phase (capsule core).

[0088] Group 1 (Polyurethane Capsule Wall): In another beaker, 2.5 g of dispersant was dissolved in 50 mL of deionized water to prepare a 2% dispersant solution, which served as the aqueous phase (containing ethylenediamine monomer). The oil phase was slowly added dropwise to the aqueous phase solution, and high-speed shear emulsification was performed for 1 h to form a stable O / W emulsion. Subsequently, polyurethane prepolymer was added, and polymerization occurred at the oil / water interface, with the reaction being carried out at a constant temperature for 4 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain multifunctional microcapsules coated with polyurethane capsule walls.

[0089] Group 2 (Polystyrene Capsule Wall): In another beaker, 2.5 g of gum arabic was dissolved in 50 mL of deionized water to prepare a 2% dispersant solution, and 0.1 g of initiator was added. The oil phase was slowly added dropwise to the dispersant solution, and high-speed shear emulsification was performed for 1 h to form a stable O / W emulsion. Subsequently, styrene monomer was added, and the temperature was raised to 70 °C, where the reaction was carried out for 6 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain multifunctional microcapsules coated with polystyrene capsule walls.

[0090] 2) Preparation of superhydrophobic ZIF-67 particles: Same as in Example 1, hydrophobic superhydrophobic ZIF-67 particles were obtained.

[0091] 3) Preparation of coating slurry: Take 10.0 g of two-component polyurethane varnish as the matrix, add 1.1 g of hydrophobic ZIF-67 particles and 1.6 g of the corresponding group of multifunctional microcapsules to each, stir at high speed with a mechanical stirrer for 25 min, and then ultrasonically disperse for 25 min to obtain two groups of uniform slurries.

[0092] 4) Coating construction: The two sets of slurries are evenly sprayed onto the sandblasted 304 stainless steel plate and cured at room temperature for 36 hours to obtain the two intelligent responsive self-healing anti-corrosion superhydrophobic composite coatings corresponding to the two capsule walls.

[0093] In summary, this invention discloses a smart, responsive, self-healing, anti-corrosion, superhydrophobic composite coating and its preparation method. The coating consists of a polymer binder, superhydrophobic functional particles, and multifunctional microcapsules. Its core innovation lies in the designed multifunctional microcapsules, whose core simultaneously encapsulates a repair agent for physical damage repair and a corrosion inhibitor for actively suppressing electrochemical corrosion. When the coating is subjected to external mechanical damage, the microcapsules rupture, simultaneously releasing the two active substances, achieving "healing" of physical scratches and "targeted corrosion inhibition" of exposed metal substrates, forming a dual repair mechanism. This invention combines the passive shielding function of superhydrophobicity with the intelligent responsive active protection function after damage, constructing a full-time, multi-layered protection system, significantly improving the reliability and service life of the protective coating in harsh service environments. The coating preparation method is simple and has significant application value in aerospace, marine engineering, transportation, and other fields.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A smart responsive self-healing anti-corrosion superhydrophobic composite coating, characterized in that, include: A polymer binder matrix, and superhydrophobic functional particles and multifunctional microcapsules dispersed in the polymer binder matrix; The multifunctional microcapsule includes: a capsule wall and a capsule core covered by the capsule wall; The core contains both a repair agent for repairing physical damage and a corrosion inhibitor for suppressing substrate corrosion.

2. The intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 1, characterized in that, The repair agent is selected from at least one of epoxy resin, isocyanate, unsaturated polyester, drying oil, microcrystalline wax and organosiloxane prepolymer.

3. The intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 1, characterized in that, The corrosion inhibitor is selected from at least one of benzotriazole, mercaptobenzothiazole, rare earth salts, phosphates and molybdates.

4. The intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 1, characterized in that, The capsule wall is selected from polyurea-formaldehyde resin, melamine resin, gelatin, polyurethane, or polystyrene.

5. The intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 1, characterized in that, The superhydrophobic functional particles are metal-organic framework particles with surfaces modified with low surface energy materials, silica particles with surfaces modified with low surface energy materials, titanium dioxide particles with surfaces modified with low surface energy materials, or zinc oxide particles with surfaces modified with low surface energy materials.

6. The method for preparing the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to any one of claims 1-5, characterized in that, Includes the following steps: 1) By using microencapsulation technology, repair agents and corrosion inhibitors are mixed and coated into the capsule wall material for polymerization reaction to prepare multifunctional microcapsules; 2) The nanoparticles were dispersed in an organic solvent, and after the addition of a low surface energy substance to carry out a surface energy modification reaction, they were separated and dried to prepare superhydrophobic functional particles. 3) Mix and disperse the multifunctional microcapsules obtained in step 1), the superhydrophobic functional particles obtained in step 2), and the polymer binder, and prepare a coating slurry by mechanical stirring and ultrasonic dispersion; 4) Apply the coating slurry to the surface of the substrate and cure it to obtain a smart responsive self-healing anti-corrosion superhydrophobic composite coating.

7. The method for preparing the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 6, characterized in that, In step 1), the microencapsulation technology is interfacial polymerization, in-situ polymerization, or complex coagulation; the conditions for the polymerization reaction include: adjusting the pH value to 3.0-3.5, the reaction temperature to 50-80℃, and the reaction time to 2-8h.

8. The method for preparing the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 6, characterized in that, In step 2), the nanoparticles are metal-organic framework particles, silica particles, titanium dioxide particles, or zinc oxide particles. The organic solvent is ethanol, n-hexane, or toluene; The low surface energy material is at least one of long-chain alkylsilane, fluoroalkylsilane and long-chain fatty acid; The surface energy modification reaction conditions include: reaction at 70-100℃ for 6-12 h.

9. The method for preparing the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 6, characterized in that, In step 3), the mass ratio of the polymer binder, superhydrophobic functional particles, and multifunctional microcapsules is 100:(5-20):(5-30) by mass parts. The mechanical stirring time is 10-60 min; the ultrasonic dispersion time is 10-60 min.

10. The method for preparing the intelligent responsive self-healing anti-corrosion superhydrophobic composite coating according to claim 7, characterized in that, In step 4), the coating method includes: spraying, brushing, or scraping. The curing method is room temperature curing or heat curing; the curing time is 0.5-72 hours.

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